Application Report SPRA588 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 Erwan Simon Digital Control Systems Abstract This application report presents a solution to control a 3-phase Permanent Magnet Synchronous motor using the Texas Instruments (TI) TMS320F240 digital signal processor (DSP). This processor is part of a new family of DSPs that enable cost-effective design of intelligent controllers for brushless motors. The use of this DSP yields enhanced operations, fewer system components, lower system cost and increased efficiency. The control method presented is field oriented control (FOC). The sinusoidal voltage waveforms are generated by the DSP using the space vector modulation technique. A practical solution is described and results are given in this application report. Contents Introduction ......................................................................................................................................................3 PMSM Model....................................................................................................................................................3 Speed and Position Definition ..............................................................................................................3 Electrical Equations ..............................................................................................................................4 Mechanical Equations ..........................................................................................................................6 FOC Control for PMSM ....................................................................................................................................6 Expression of the Stator Current Vector ...............................................................................................6 The Clarke and Park Transformations..................................................................................................7 PMSM Control Structure.....................................................................................................................10 Application Description ..................................................................................................................................11 Motor Characteristics..........................................................................................................................11 DSP Development Board ...................................................................................................................11 Power Electronics Board ....................................................................................................................12 Software Organization....................................................................................................................................12 Initialization Module Description .........................................................................................................13 Interrupt Module Description ..............................................................................................................13 Fixed-Point Arithmetic....................................................................................................................................18 Representation of Numbers................................................................................................................18 PU Model and Base Values................................................................................................................20 Core Modules.................................................................................................................................................21 Co-ordinate Transformations..............................................................................................................21 Generation of Sine and Cosine ..........................................................................................................23 Space Vector Modulation ...................................................................................................................24 PI Regulators......................................................................................................................................34 Interface Modules ..........................................................................................................................................35 Current Sensing Module.....................................................................................................................35 Current Scaling Module ......................................................................................................................39 Digital Signal Processing Solutions September 1999 Application Report SPRA588 Mechanical Position Sensing and Scaling Module .............................................................................41 Electrical Position Scaling Module......................................................................................................45 Mechanical Speed Scaling Module ....................................................................................................46 Experimental Results .....................................................................................................................................49 User Interface ................................................................................................................................................52 Software Modularity .......................................................................................................................................53 Conclusion .....................................................................................................................................................54 Software Variables.........................................................................................................................................56 Appendix A. TMS320F240 FOC Software .....................................................................................................57 Appendix B. Qbasic Graphic User’s Interface................................................................................................80 Appendix C. Linker Command File ................................................................................................................84 Figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. Figure 27. Figure 28. Three-phase Motor with 4 Magnet Poles (2 Pole Pair) ...............................................................4 Stator Current Vector..................................................................................................................7 (a,b,c)->(α,β ) Projection (ClarkeTransformation) ......................................................................7 (α,β )->(d,q) Projection (Park Transformation) ...........................................................................8 PMSM Control Structure...........................................................................................................10 Top View of the TMS320F240 Evaluation Module....................................................................12 Software Flowchart and Timing ................................................................................................14 Rotor Flux Position at Standstill................................................................................................15 Stalled Rotor.............................................................................................................................15 +90° Electrical Shift..................................................................................................................16 Interrupt Module Flowchart .......................................................................................................17 Sinθe, Cosθe Calculation using the Sine Look-up Table ..........................................................24 3-Phase Equilibrate System .....................................................................................................25 Power Bridge ............................................................................................................................26 Voltage Vectors ........................................................................................................................28 Projection of the Reference Voltage Vector .............................................................................29 Table Assigning the Right Duty Cycle to the Right Motor Phase..............................................32 Sector 3 PWM Patterns and Duty Cycles.................................................................................32 Current Sensing Hardware .......................................................................................................35 Current Sensing Scale Translation...........................................................................................36 Scaling Factor Representation .................................................................................................39 Incremental Optical Encoder ....................................................................................................42 Sensing Scale...........................................................................................................................43 Electrical Position Scaling ........................................................................................................45 Mechanical Speed Scale ..........................................................................................................47 Transient Stator Phase A Current ............................................................................................49 Transient Currents isd, isq at Start ...........................................................................................50 Speed Transient from 0 to 1000 rpm........................................................................................51 Table 1. Table 2. Table 3. Table 4. Table 5. Power Bridge Output Voltages (VAO, VBO, VCO) ........................................................................26 Power Bridge Output Voltages (VAN, VBN, VCN).........................................................................27 Stator Voltages .........................................................................................................................28 Motor at 500 rpm ......................................................................................................................51 Motor at 1500 rpm ....................................................................................................................51 Tables Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 2 Application Report SPRA588 Introduction A brushless Permanent Magnet Synchronous motor (PMSM) has a wound stator, a permanent magnet rotor assembly and internal or external devices to sense rotor position. The sensing devices provide logic signals for electronically switching the stator windings in the proper sequence to maintain rotation of the magnet assembly. The combination of an inner permanent magnet rotor and outer windings offers the advantages of low rotor inertia, efficient heat dissipation, and reduction of the motor size. Moreover, the elimination of brushes reduces noise, EMI generation and suppresses the need of brushes maintenance. Two configurations of permanent magnet brushless motor are usually considered: the trapezoidal type and the sinusoidal type. Depending on how the stator is wounded, the back-electromagnetic force will have a different shape (the BEMF is induced in the stator by the motion of the rotor). To obtain the maximum performance from each type of PMSM, an appropriate control strategy has to be implemented. The trapezoidal BEMF motor called DC brushless motor (BLDC) uses a "two phases on" strategy, whereas the sinusoidal BEMF motor offers its best performances when driven by sinusoidal currents (three phases on strategy). This application report presents the implementation of a control for sinusoidal PMSM motor. The sinusoidal voltage waveform applied to this motor is created by using the Space Vector modulation technique. The Field Oriented Control algorithm will enable real-time control of torque and rotation speed. As this control is accurate in every mode of operation (steady state and transient), no oversize of the power transistors is necessary. The transient currents are constantly controlled in amplitude. Moreover, no torque ripple appears when driving this sinusoidal BEMF motor with sinusoidal currents. PMSM Model The operation of a brushless PM motor relies on the conversion of electrical energy to magnetic energy and then from magnetic energy to mechanical energy. It is possible to generate a magnetic rotating field by applying sinusoidal voltages to the 3 stator phases of a 3 phase motor. A resulting sinusoidal current flows in the coils and generates the rotating stator flux. The rotation of the rotor shaft is then created by attraction of the permanent rotor flux with the stator flux. Speed and Position Definition In electric motors, two measures of position and speed are usually defined: mechanical and electrical. The mechanical position is related to the rotation of the rotor shaft. When the rotor shaft has accomplished 360 mechanical degrees, the rotor is back in the same position where it started. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 3 Application Report SPRA588 The electrical position of the rotor is related to the rotation of the rotor magnetic field. In Figure 1, the rotor needs only to move 180 mechanical degrees to obtain an identical magnetic configuration as when it started. The electrical position of the rotor is then related to the number of magnetic pole pairs on it. Figure 1. Three-phase Motor with 4 Magnet Poles (2 Pole Pair) S S The electrical position of the rotor is linked to the mechanical position of the rotor by the relationship θ e = θ m* p ( p is the number of pole pair). As the speed is related to the position by ω = dθ/dt , a similar relationship also exists towards electrical speed and mechanical speed. ω e = ω m* p The notions of electrical position of the rotor and mechanical speed are extensively used in this report. Electrical Equations va = V cos(ωe * t ) 2π ) 3 4π vc = V cos(ωe * t − ) 3 vb = V cos(ωe * t − To create the rotating stator flux, the commonly applied phase voltages present a phase shift of 120 electrical degrees from one to another that takes into account the mechanical 120 degrees angle between coils. A one phase electrical equation can be written like : Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 4 Application Report SPRA588 v = Z * i = Ri + dΨ d = Ri + ( Li + Ψm (θ )) dt dt where ψm corresponds to the amplitude of the natural magnetic flux of the permanent d Ψm(θ ) corresponds to the back-emf (induced voltage) and can dt dΨm(θ ) also be written like * ωe , where ωe corresponds to the electrical speed. dθ magnets. The term Supposing that the machine is sinusoidal, the induced voltage has the following form: sin(θe) Ea (θ ) 2π E = Eb (θ ) = −ωe * Ψm sin(θe − ) = ωe * Ψm * [K (θe)] 3 Ec (θ ) 4π sin(θe − ) 3 From the electrical power delivered to the motor, a part of it is transformed in Joule losses, another part is going to the energy stored in the magnetic field and the last part is transformed in mechanical energy (torque production). In the PMSM case, the torque is expressed by: Te = p * [Is ] * Ψ m * [K (θe )] , where p is the number of pole pairs. t It can be proven that the best solution to produce a constant torque is to drive a sinusoidal motor by sinusoidal currents. Te = pΨm ( Ia * Ka (θ ) + Ib * Kb(θ ) + Ic * Kc (θ )) Knowing that : Ia = Is sin(ωe * t ) 2π ) 3 4π Ic = Is sin(ωe * t − ) 3 Ib = Is sin(ωe * t − We obtain Te = p * Ψm * Is (sin 2 (ωt ) + sin 2 (ωt − 2π 4π 3 ) + sin 2 (ωt − )) = p * Ψm * Is . It will be 3 3 2 further shown that the FOC enables a continuous control of the torque demand without ripples. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 5 Application Report SPRA588 Mechanical Equations The torque created by the energy conversion process is then used to drive mechanical loads. Its expression is related to mechanical parameters via the fundamental law of the dynamics as follows: ∑T = J Giving: dw dt J : rotor inertia Kd: viscosity coefficient Tl: load torque ω m: mechanical speed J dωm + kdωm + Tl = Te dt As the torque is composed of time and electrical position dependent parameters, its efficient and accurate control is not easy with standard methods. The proposed solution is to overcome this issue is based on the real time implementation of the Field Orientated Control algorithm with a TMS320F240 DSP. FOC Control for PMSM The goal of the Field Oriented Control [BPRA073] is to perform real-time control of torque variations demand, to control the rotor mechanical speed and to regulate phase currents in order to avoid current spikes during transient phases. To perform these controls, the electrical equations are projected from a 3 phase nonrotating frame into a two co-ordinate rotating frame. This mathematical projection (Clarke & Park) greatly simplifies the expression of the electrical equations and remove their time and position dependencies. Expression of the Stator Current Vector As phase current values are used in the general expression of the torque, the expression of their values in the new rotating frame are needed afterwards. The three sinusoidal currents created by the 120° (electrical) phase shifted voltages applied to the stator are also 120° (electrical) phase shifted one from another. The stator current vector (Figure 2) is represented in the 3 phase nonrotating frame j2π/3 j4π/3 (a,b,c) and defined by is = ia + e ib +e ic Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 6 Application Report SPRA588 Figure 2. Stator Current Vector b αib iS α2ic ia a c The Clarke and Park Transformations The idea of the Clarke transformation is that the rotating stator current vector that is the sum of the 3 phase currents can also be generated by a bi-phased system placed on the fixed axis α and β as shown in Figure 3. Figure 3. (a,b,c)->(α,β) Projection (ClarkeTransformation) b β iSβ iS iSα α=a c Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 7 Application Report SPRA588 The projection of the stator current vector in this fixed frame gives: isα = ia isβ = 1 2 ⋅ ia + ib 3 3 ia + ib + ic = 0 In this new frame, the expression of the torque is still dependent on the position of the rotor flux, preventing any easy solution of the electrical differential equation. To remove this dependency, the electrical equations are projected in a 2-phase (d,q) system (Figure 4) that rotates at the speed of the electrical speed of the rotor and where the d axis is aligned with the electrical position of the rotor flux. In this frame, the electrical expression of the torque becomes independent from θe. Figure 4. (α,β)->(d,q) Projection (Park Transformation) β q i Sβ i Sq iS ΨR d θe i Sd i Sα α= a The equations corresponding to this transformation are given by: isd = isα ⋅ cos(θe) + isβ ⋅ sin(θe) isq = −isα ⋅ sin(θe) + isβ ⋅ cos(θe ) In this new system, the expression of the electrical equations are greatly simplified: d ϕrd − ωe *ϕrq dt d Vsq = Rs * iq + ϕrq + ωe *ϕrd dt Vsd = Rs * id + Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 8 Application Report SPRA588 For a multiple pole synchronous motor, the expression of the torque in (d,q) is: T e = 3 p (ψ 2 rd * i sq − i sd * ψ rq ) Where p is the number of pole pairs. In the specific case of a permanent magnet synchronous motor without salient poles, most of the natural magnetic flux is on the d axis (ψrd >> ψrq). Moreover, the stator current vector value is is = isd2 +isq2 In order to optimize the torque production for a given is value, the appropriate strategy is to set isdref to 0. The action of the current regulators is then to shift the current vector Is onto the q axis. The torque is now given by Te ∝ ψrd * isq The relationship between mechanical speed and torque is given by the mechanical differential equation. To overcome the nominal speed limitation, a field-weakening algorithm can be implemented with a non-zero isdref.. Setting isdref to a non-zero value will increase the speed range but the applicable torque must be reduced to ensure that the relationship i s = i sd2 +i sq2 ≤ i s max is respected. Moreover, it is not recommended to create a magnetic flux opposed to the natural flux of the permanent magnets over long periods of time. This could lead to demagnetization of the rotor magnets reducing the torque production, as well as excessive heat generation. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 9 Application Report SPRA588 PMSM Control Structure The control scheme proposed for the Speed FOC PMSM drive is shown in Figure 5. Figure 5. PMSM Control Structure nref PI iSqref PI vSqref Park -1 t. d,q iSdref PI vSdref α,β VDC vSαref vSβref SV PWM 3-phase Inverter va vb vc iSq n iSd θe position and speed sensing d,q α,β iSα α,β ia iSβ ib Park t. Sensor informations a,b,c Clarke t. PMSM motor Figure 5 shows the software modules with the hardware of the solution. A detailed description of both aspects will be given in dedicated paragraphs. ia and ib are measured with a current sensor. The Clarke transform is applied to them to determine the stator current projection in a two co-ordinate non-rotating frame. The Park co-ordinate transformation is then applied in order to obtain this projection in the (d,q) rotating frame. The (d,q) projections of the stator phase currents are then compared to their reference values Isqref and Isdref (set to 0) and corrected by mean of PI current controllers. The outputs of the current controllers are passed through the inverse Park transform and a new stator voltage vector is impressed to the motor using the Space Vector Modulation technique. In order to control the mechanical speed of the motor (speed FOC), an outer loop is driving the reference current Isqref. The mechanical speed reference is denoted “nref“ and the mechanical speed “n” for notations compliance with previous FOC application notes. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 10 Application Report SPRA588 Application Description This chapter covers each component put in place to implement the solution of the PMSM drive. The different elements of the application are: r 6-pole PMSM motor r DSP development board r Power board Motor Characteristics The PMSM motor used for the application is a 6-pole three phase Y-connected motor. The characteristics of this motor are as follow: Stator phase line to line inductance: line to line resistance Pole pairs Nominal Torque Tn Nominal speed Motor nominal power Pn Mechanical time constant Electrical time constant Torque constant Voltage constant 4.8mH 2.1Ω 3 2.2Nm 3000rpm 690W 1.5ms 2.3ms 0.76Nm/A rms 65Vpk/krpm An embedded incremental encoder with a resolution of 1024 lines/revolution provides feedback for speed control. DSP Development Board Several TMS320F240 development platforms are available on the market either from TI or from one of its third parties. The TMS320F240 Evaluation Module (Figure 6) introduced by TI has been used in this application. The on-board DACs are used to output the values of several variables (currents, voltages, speed, and position) chosen from the Graphical User Interface presented at the end of this report. This feature is particularly useful in development stage. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 11 Application Report SPRA588 Figure 6. Top View of the TMS320F240 Evaluation Module The PLL unit is set for CPUCLK = 20MHz and SYSCLK = 10Mhz. To disable the Watchdog unit, set Vccp pin voltage to 5V (JP5 position 2-3) Power Electronics Board The power hardware used to implement and test this PMSM drive is based on six power IGBT (IRGPC40F) driven by the DSP Controller via the integrated driver IR2130 This power inverter supports a rectified DC bus voltage of 310V and a maximum current of 10A. The DSP PWM (pulse width modulation) outputs are isolated from the power board by opto-couplers. The phases current sensing is performed via two current voltage transducers (LEM type) supplied with +/-15V. Their maximum input current is +/-10A, which is converted into a 2.5V output voltage. Software Organization The program FOCPMSM.ASM is based on two modules: the initialization module and the interrupt module. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 12 Application Report SPRA588 Initialization Module Description After a processor reset, the initialization module performs the following tasks: r DSP setup : core, watchdog, clocks, ADC, SCI, general purpose IO, event manager r Variables initializations : default values r Interrupt source selection and enable r Waiting loop The waiting loop implemented corresponds to an interruptible communication between the DSP and a Graphical User Interface. The DSP communicates via its asynchronous serial port to the COM port of a PC. The user can send commands via this RS232 link and update variables and flags from the computer. Interrupt Module Description The interrupt module handles the whole FOC algorithm. It is periodically computed according to a fixed PWM (pulse width modulation) period value. The choice of the PWM frequency depends on the motor electrical constant L/R. If the PWM frequency is too low, audible noise can be heard from the motor. Usually, PWM frequencies are in the range of 20 kHz. In this report, a PWM frequency of 16kHz has been chosen. In Figure 7, the sampling period T of 60 µs (16 kHz) is established by setting the timer period T1PER to 600 (PWMPRD=600). This timer is set in up-down count mode and generates a periodical interrupt on T1 underflow event. The goal of the interrupt module is to update the stator voltage reference and to ensure the regulation of stator currents and rotor mechanical speed. After the initialization module has completed, the rotation does not start immediately. As the program is interactive, the DSP waits for the user to select the Init/run menu option that set the internal flag “initphase”. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 13 Application Report SPRA588 Figure 7. Software Flowchart and Timing Start Hardware Initialization SW Variables Initialization Waiting Loop PWM ISR PWM Underflow Interrupt Sampling Period T=60µσ =2*PWMPRD T1CNT PWMPRD=600*50ns=30 Initialization µs τ algorithm Waiting Time τ algorithm Software Start Depending on the status of this flag, either a magnetic stall or the complete speed FOC algorithm is performed. If initphase = 0, the magnetic stall places the rotor in a known position at start. It is necessary for two reasons: r The embedded encoder does not give an absolute information on the rotor position. Only a relative position can be computed from a known position. r The rotor electrical position needs to be reset for the FOC. This stall is performed by applying a constant voltage vector to the stator phase: the constant phase currents flowing in the coils create a fixed stator flux. As a consequence, the rotor flux aligns itself naturally onto this stator flux (the rotor is stalled in this position). The component Iq of the stator current vector is set to the value Iqrinit (=Inominal), Id is set to 0. The arbitrary angular position of this vector is called θe. ° If initphase = 1, the electrical angle θe is shifted by 90 . As a consequence, the (d,q) axis ° are rotated from 90 apart. The d axis corresponds now to the real rotor flux position and the stator current vector Is is moved to the new q axis. As a consequence, the rotor flux tends to align itself with the new stator flux vector position. As soon as the rotor starts to rotate, relative displacement information is sent to the DSP by the encoder. A new stator vector is computed every interrupt in order to maintain the 90 electrical degrees between the two fluxes. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 14 Application Report SPRA588 These two steps are graphically explained below. Start of the Motion After reset, the rotor flux is in an unknown position (Figure 8). Figure 8. Rotor Flux Position at Standstill β b ψ r α= a c Step 1: Initphase = 0 A fixed stator current vector Isref is applied to the motor. The components of this vector are: Isdref=0, Isqref=Iqrinit (=Inominal), θe Figure 9. Stalled Rotor β q Ψr d i sβ Isref θe i sα α=a The rotor flux aligns itself to the axis q. For the time being, the (d,q) axis is not yet rotating. The rotor flux is in a known position but this position is not yet aligned with the d axis. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 15 Application Report SPRA588 Step 2: Initphase = 1 90 electrical degrees is added to the value of θe, this action is equivalent to a frame rotation. Figure 10. +90° Electrical Shift β d Ψr θe is q Isβ α=a Isref o Instantaneously, the stator current reference vector is moved 90 apart from its first position. (The rotor is physically at the same position as previously). The d axis now corresponds exactly to the position of the rotor flux. o As there is this 90 angular difference between the rotor flux and the stator flux, the interaction of the two fluxes produces torque and the rotor starts to rotate in order to align itself with Isref. The incremental encoder sends rotor position information to the DSP. This information is stored in a software counter called “encoder”. Every PWM interrupt, the stator voltage vector is updated to maintain the 90° between the two magnetic fluxes. This update is done according to the number of increments stored in the variable encoder. o For convenience , initial value θe of has been chosen in this report to be equal to -90 . o This makes the d axis correspond to the 0 electrical position at start. In fact, the electrical position is now computed with the formula θe = K*encoder. As the number of increments in the variable encoder are null after reset, it was convenient to choose the o value -90 as first value for θe. The flowchart of the interrupt module is given in Figure 11. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 16 Application Report SPRA588 Figure 11. Interrupt Module Flowchart start control routine _c_int2 Ia,Ib current sampling Init Init / Run? Run calculate rotor flux displacement θelec = K * encoder speedstep = 0 ? YES calculate speed n = Kspeed*speedtmp NO speed regulator n_ref - n --> iqr update speed counter speedtmp += encincr sampled current scaling i = Kcurrent*ADC value Stall the rotor θelec = -90deg Iqref= # Iqrinit Idref = 0 encoder = 0 (a,b,c)->(α,β) C larke Transformation ( α,β)->(d,q) Park Transform q-current regulator d-current regulator (d,q)->(α,β) Inv Park Transformation SVPW M End Control Routine Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 17 Application Report SPRA588 On the interrupt module flowchart, several software blocks appear. The shadowed blocks correspond to interface modules, whereas the nonshadowed blocks correspond to the core modules. The interface modules are low level routines that convert real wold data into their suitable numerical counterparts. The core modules use these formatted data to execute the several tasks of the FOC. In order to be able to understand how the software modules have been implemented on the TMS320F240, an overview on the fixed-point arithmetic is needed. The Per-Unit model will also be discussed in the following section. Fixed-Point Arithmetic Representation of Numbers In binary format, a number can be represented in signed magnitude, where the left-most bit represents the sign and the remaining bits represent the magnitude: 3 2 1 0 +6 (decimal) is represented as 101102 (binary) = 1*(0*2 +1*2 +1*2 +0*2 ) 3 2 1 0 -6 (decimal) is represented as 101102 (binary) = -1*(0*2 +1*2 +1*2 +0*2 ) Two’s complement is an alternative form of representation used in most processors, including the TMS320. The representation of a positive number is the same in two’s complement and in signed magnitude. However, the representation of a negative number is different. 4 3 2 1 0 +6 (decimal) is represented as 00110 (2s-comp) = 0*2 +0*2 +1*2 +1*2 +0*2 2 4 3 2 1 0 -6 (decimal) is represented as 11010 (2s-comp) = -1*2 +1*2 +0*2 +1*2 +0*2 2 The above words are represented on 5 bits only. The TMS320F240 is part of the TMS320C2xx 16bit fixed-point DSP family of TI. The native length of a word is 16bit on this family. To represent real numbers on this fixed-point architecture, a Qk format has to be chosen by the user. Qk numbers can be represented by the following general formula: Z = -b 15-k 14-k -1 -2 -k *2 +b *2 +…b +b *2 + b *2 +…+ b *2 15-k 14-k 0 -1 -2 -k An implied dot separates the integer part from the fractional part of the Qk number where k represents the quantity of fractional bit. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 18 Application Report SPRA588 For instance the real number π (3.14159) can be represented in Q13 with finite precision as follow : 2 1 0 -1 -2 -3 -4 -5 011.0 0100 1000 0111 = 0*2 + 1*2 + 1*2 + 0*2 + 0*2 + 1*2 + 0*2 + 0*2 + 2 -6 -7 -8 -9 -10 -11 -12 -13 1*2 + 0*2 + 0*2 + 0*2 + 0*2 + 1*2 + 1*2 + 1*2 The number of bits dedicated to the fractional part affects the accuracy of the result while the integer part affects the dynamic range of values that can be represented. The Q15 format offers the best precision but only real numbers comprised between –1 and +1 can be represented. The Qk format offers a compromise between dynamic range and precision. The Q12 numeric format is used in the major part of this report : 4 bits are dedicated to the integer -12 part and 12 bits are dedicated to the fractional part. The precision of this format is 2 (0.00024414). The represented numbers are in the range of [-8;8] to ensure that values can handle each drive control quantity, not only during steady state operation but also during transient operation. Arithmetic operations Multiplication The following example shows how two real numbers (X and Y) coded in Q12 are multiplied X = -1.125 is represented as 1110. 1110 0000 0000 in Q12 10 2 Y = +1.375 is represented as 0001. 0110 0000 0000 in Q12 10 2 * 0001 011(0 0000 0000) (+1.375) 1110 111(0 0000 0000) (-1.125) 0001 011 0 0010 11 . 00 0101 1 . . 000 0000 . . . 0001 011 . . . . 1 1101 01 . . . . . (2-scompl.) SUM1= 00100001+(zeroes) SUM2=001001101+(zeroes) SUM3=0001001101+(zeroes) SUM4=00011111101+(zeroes) z = 1 1111 0.011 101(00…00) (-1.546875) 18 zeroes Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 19 Application Report SPRA588 k p k+p The multiplication of a Qk (2 ) number by a Qp (2 ) number results in a Qk+p (2 ) 3 5 8 number (the same rule also exists in base 10. ex : 10 *10 = 10 ). In the case of a Q12 by Q12 multiplication, the virtual dot is shifted and the 24 least significant bits of the 32-bit accumulator represents the fractional part of the result (Q12 *Q12= Q24 ). As the result of the multiplication gives a 30bit number, the SXM bit (sign extension mode) is set to propagate the sign to the two most significant bits of the accumulator. Z will be stored back in Q12 format. To do so, the content of the accumulator is left shifted four times and the upper word of the accumulator is stored in Z. Z is stored as 1110. 0011 1010 0000 in Q12 = -1.546875 (decimal) 2 Addition The following example shows how two real numbers (X and Y) coded in Q12 are added. X = +1.125 is represented as 0001. 0010 0000 0000 in Q12 10 2 Y = +1.375 is represented as 0001. 0110 0000 0000 in Q12 10 2 Z is stored as 0010. 1000 0000 0000 in Q12 = 2.5 (decimal) 2 PU Model and Base Values The Per Unit model (PU) is associated with reduced value notion. As the TMS320F240 is a fixed-point DSP, it has been shown that the greatest precision is obtained in Q15 format but the dynamic range of this format is small: it is comprised between –1 and +1 only. Using a fixed-point DSP, it is necessary to reduce the amplitude of the variables in order to get a fractional part with a maximum precision. The notion of Per Unit model is introduced to use this fixed-point feature. It is usually associated with the nominal values of the motor. The per-unit current is usually defined as ipu = I / Inominal The above equation shows that ipu = 1 when the current reaches its nominal value. Instead of using the nominal value as reference, a base value is preferred. For currents and voltages, the reason to choose a base different from the nominal values is that nominal values usually given by the motor manufacturer are RMS (root mean square). Then, the preferred Per Unit model for the current is given by: i = I / Ibase where I base = Inominal * 2 and the PU model for the voltage is given by: v = V / Vbase where Vbase = Vnominal * 2 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 20 Application Report SPRA588 For this application, the other PU model defined is: n= mechanical rotor speed ω base In this application report, the base value of the mechanical speed corresponds to its nominal value. I base = 2 I n = 2 ⋅ 2.9 = 4.1A Vbase = 2Vn = 2 ⋅ 127 ≅ 180V ω base = 2πf n = 2π ⋅ 50 = 314.15 Ψbase = rad sec Vbase 180 = = 0.571Wb ω base 314.15 As mentioned earlier, transient currents (for instance) might reach higher values than their nominal values. Furthermore, the motor speed range might be extended above the nominal speed (field weakening), then every per unit value might be greater than one. This remark forces the implementation to handle these situations and thus the suited numerical format chosen was Q12 for the PU models. The Q12 representation of 1 is 1000h. The PU value is equal to 1 when the value is equal to its base. Core Modules The core modules use formatted data to execute the different tasks of the FOC. The core modules described are: r Co-ordinate transformations : Clarke, Park, Park -1 r Generation of sinθ, cosθ with a lookup table. r Variable stator voltage vector generation : Space Vector Modulation algorithm r Speed regulation, current regulation Co-ordinate Transformations As first approach for the application of the fixed-point representation concept, the implementation of the Clarke geometrical transformation is explained below. The other -1 modules (Park, Park ) are also implemented in the program FOCPMSM.ASM. These transformations are also explained in Clarke & Park Transforms on the TMS320C2xx (BPRA048). Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 21 Application Report SPRA588 As mentioned previously, the stator phase current vector is projected from a 3-phase (a,b,c) system in a (α,β) non-rotating frame by the Clarke transformation. The mathematical equations are: iα = ia iβ = 1 2 ib ⋅ ia + 3 3 ia + ib + ic = 0 The following assembly function handles this mathematical transformation: ********************************************* * (a,b,c) -> (alfa,beta) axis transformation * iSalfa = ia * iSbeta = (2 * ib + ia) / sqrt(3) ********************************************* * Input variables : ia,ib Q12 format * Output variables : iSalfa, iSbeta Q12 format * Local variables modified : tmp Q12 format lacc ia sacl iSalfa lacc ib,1 add ia sacl tmp lt tmp mpy SQRT3inv ;iSbeta = (2 * ib + ia) / sqrt(3) ;SQRT3inv = (1 / sqrt(3)) = 093dh ;4.12 format = 0.577350269 pac sach iSbeta,4 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 22 Application Report SPRA588 This routine gives a practical example of multiplication of Q12 numbers.To easily find the -1 correspondence between the fractional format of SQRT (3) and its Q12 equivalent, a 12 simple multiplication by 2 (= 4096) has to be done: 0. 577350269 * 4096 ≈ 2365 à 093Dh The Clarke (a,b,c)->(α,β) projection requires 9 words of ROM, 5 words of RAM. A complete table of each function requirements is given in the conclusion. -1 The Park and Park are also implemented in FOCPMSM.ASM. Generation of Sine and Cosine -1 The Park and Park use the value of the rotor electrical position in order to handle the stator current vector projection in a rotating frame. The electrical position is not directly used in this transforms but the sine and cosine values of this electrical position. To obtain both sine and cosine from the electrical angle, a sine look-up table has been implemented. The table contains 256 words to represent sine values of electrical angles in the range [0;360°]. As a result, the resolution on θe is limited to 360/256 =1.40625°. θe = electrical angle / 360° (with θe in the range [0;FFFh]) θe varies from 0 to 4095 (see position sensing module). As only 256 words are available to represent this range, θe is divided by 16 and stored into the variable index that will be used to address the lookup table. The content of the table raw pointed by the index is fetched in indirect addressing mode via AR5 auxiliary register. This content coded in Q12 is stored in the variable sin that will be used in the Park transforms. Note that to get the cosine value of the electrical angle, 90° are added to θe This operation corresponds to add 64 (256/4) to the value of index. The result is stored in the variable cos. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 23 Application Report SPRA588 Figure 12. Sinθe, Cosθe Calculation using the Sine Look-up Table sine table address θe index 0 101 201 0 + >>4 4091 4095 4096 4095 4091 π/2 201 101 0 65435 65335 π 61445 61441 61440 61441 61445 3π/2 65335 65435 2π Space Vector Modulation The Space Vector Modulation is used to generate the voltages applied to the stator phases. It uses a special scheme to switch the power transistors to generate pseudo sinusoidal currents in the stator phases. This switching scheme comes from the translation of the (α,β) voltage reference vector into an amount of time of commutation (on/off) for each power transistors. In order to understand some of the assumptions made in the case of the rectified voltage, a brief description of three phase systems is described in the following section. . Expression of the 3 Phase Voltages (Phase to Neutral) Previously, the method used to generate a rotating magnetic field was to use three independent voltage sources that were dephased from 120 degrees from one another. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 24 Application Report SPRA588 Figure 13. 3-Phase Equilibrate System Voa . A I1 Z Vob O B . I2 . I3 Z .N Z Voc C PMSM In this standard tri-phased system, 3 sinusoidal voltages are applied to each of the motor phases to generate the sinusoidal currents. These voltages can be expressed as follows: Voa = V 2 cos(ωe * t ) 2π ) 3 4π Voc = V 2 cos(ωe * t − ) 3 Vob = V 2 cos(ωe * t − In order to calculate the phase to neutral voltages (respectively Van, Vbn, Vcn) from the applied source voltages (respectively Voa, Vob, Voc), the assumption is made that the system is equilibrated is made. This leads to the following equations: Von = Voa +Z*I1 Von = Vob +Z*I2 Von = Voc +Z*I3 then 3*Von= Voa+Vob+Voc+Z(I1+ I2 +I3) where (I1+ I2 +I3) = 0 As Von is now expressed by a combination of the source voltages, the phase to neutral voltage for phase A can be calculated as: Van = Von-Voa = (1/3)(Voa+Vob +Voc)-Voa = -2/3Voa +1/3Vob +1/3Voc Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 25 Application Report SPRA588 The same calculation is made for the three phases leading to : Van = (1/3)(2*Vao-Vbo-Vco) Vbn = (1/3)(2*Vbo-Vao-Vco) Vcn = (1/3)(2*Vco-Vao-Vbo) Application to the Static Power Bridge In the case of a static power bridge, sinusoidal voltage sources are not used. They are replaced by 6 power transistors that act as on/off switches to the rectified DC bus voltage. The goal is to recreate a sinusoidal current in the coils to generate the rotating field. Owing to the inductive nature of the phases, a pseudo sinusoidal current is created by modulating the duty cycle of the power switches. In Figure 14, the power transistors are activated by the signals (a,b,c) and their complemented values. Figure 14. Power Bridge Only eight combinations of the switches are possible with this configuration (Table 1). The applied voltages are referenced to the virtual middle point of rectified voltage. Table 1. Power Bridge Output Voltages (VAO, VBO, VCO) A B C VAO VBO VCO 0 0 0 -VDC/2 - VDC/2 - VDC/2 0 0 1 - VDC/2 - VDC/2 + VDC/2 0 1 0 -VDC/2 +VDC/2 - VDC/2 0 1 1 -VDC/2 +VDC/2 + VDC/2 1 0 0 +VDC/2 -VDC/2 - VDC/2 1 0 1 +VDC/2 -VDC/2 + VDC/2 1 1 0 +VDC/2 +VDC/2 - VDC/2 1 1 1 +VDC/2 +VDC/2 + VDC/2 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 26 Application Report SPRA588 Because of the equations : Van = (1/3)(2*Vao-Vbo-Vco) Vbn = (1/3)(2*Vbo-Vao-Vco) Vcn = (1/3)(2*Vco-Vao-Vbo) It is possible to express each phase to neutral voltages, for every combination of the power transistors as listed in Table 2. Table 2. Power Bridge Output Voltages (VAN, VBN, VCN) A B C VAN VBN VCN 0 0 0 0 0 0 0 0 1 - VDC/3 - VDC/3 2VDC/3 0 1 0 - VDC/3 2VDC/3 - VDC/3 0 1 1 -2VDC/3 VDC/3 VDC/3 1 0 0 2VDC/3 - VDC/3 - VDC/3 1 0 1 VDC/3 -2VDC/3 VDC/3 1 1 0 VDC/3 VDC/3 -2VDC/3 1 1 1 0 0 0 Expression of the Stator Voltages in the (α α,β β) Frame In the FOC algorithm, the control variables are expressed in a rotating frame. It has been mentioned that the current vector Isref that directly controls the torque is transformed in a -1 voltage reference vector by the Park transform. This voltage reference is expressed in the (α,β) frame. To make the relationship between the 3 phase voltages (VAN, VBN and VCN) and the voltage reference vector, the 3 phase voltages are also projected in the (α, β) frame. The expression of the 3 phase voltages in the (α,β) frame are given by the general Clarke transform equation: 1 1 − Vsα 2 2 Vsβ = 3 3 0 2 1 VAN 2 VBN 3 − VCN 2 − Since only 8 combinations are possible for the power switches, Vsα and Vsβ can also take only a finite number of values in the (α,β) frame according to the status of the transistor command signals (a,b,c). Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 27 Application Report SPRA588 Table 3. Stator Voltages A B C Vα Vβ 0 0 0 0 0 0 0 1 − VDC 3 0 1 0 − VDC 3 0 1 1 1 0 0 1 0 1 VDC 3 1 1 0 VDC 3 VDC 3 1 1 1 0 0 − VDC 3 VDC 3 2 − VDC 3 2 VDC 3 − r V0 r V1 r V2 0 r V3 0 r V4 VDC 3 r V5 r V6 r V7 The eight voltage vectors defined by the combination of the switches are represented in Figure 15. Figure 15. Voltage Vectors V2 (010 ) β V6 (110 ) 1º 3º 5º V7 (111) V3 (011 ) V4 (011) V0 (000 ) α 2º 4º 6º V1 (001 ) V5 (101) -1 Now, given a reference voltage (coming from the Park transform), the following step is to use the 8 above defined vectors to approximate this reference voltage. Projection of the Stator Reference Voltage Vs The method used to approximate the desired stator reference voltage with only eight possible states of switches is to combine adjacent vectors of the reference voltage and to modulate the time of application of each adjacent vector. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 28 Application Report SPRA588 Figure 16. Projection of the Reference Voltage Vector β V6 (110) Vsβref Vsref T6 V T 6 θ 60° V4 (100) x T4 V T 4 α Vsαref In Figure 16, the reference voltage Vsref is in the third sector and the application time of each adjacent vector is given by: T = T4 + T6 + T0 r T4 r T6 r V = sref T V4 + T V6 The determination of the amount of times T4 and T6 is given by simple projections: T6 r sβref = V V 6 cos(30°) T T4 r V4 + x Vsαref = T Vsβref x = tg (60°) Finally, with the (α,β) components values of the vectors given in the previous table, the amount of times of application of each adjacent vector is: T (3Vsαref − 3Vsβref ) 2VDC T T6 = 3 Vsβref VDC T4 = Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 29 Application Report SPRA588 The rest of the period is spent in applying the null vector. The variable T/VDC is named VDCinvT. T is the period of the PWM interrupt and VDC is the rectified DC voltage. To keep proportions in the software implementation, the variables VDC and VDCinvT are expressed in P.U and in Q12 as follow: v DC = VDC 310 = = 1.722 ⇔ 1B8 Eh 4.12 f Vbase 180 where VDC is the DC bus voltage and vDC its correspondent PU value. v DCinvT = T PWMPRD 600 ⇔ = = 348 ⇔ 15Ch 2v DC v DC 1.722 For every sector, a commutation duration is calculated. The amount of times of vector application can all be related to the following variables: X = 3v DCinvT v Sβref Y= 3 3 v DCinvT v Sβref + v DCinvT v Saref 2 2 Z= 3 3 v DCinvT v Sβref − v DCinvT v Saref 2 2 In the previous example for sector 3, T4 = -Z and T6 = X. In order to know which of the above variable apply, the knowledge of the sector in which the reference voltage vector is, is needed. To determine this sector, a simple approach is to calculate the projections Va, Vb and Vc of the reference voltage vector in the (a,b,c) plane. These projections are then compared to 0. -1 The projections Va, Vb and Vc are given by the Clarke transform as follow: va = v Sβref 1 ( 3v Sαref − v Sβref ) 2 1 vc = (− 3v Sαref − v Sβref ) 2 vb = The complete algorithm performed by the Space Vector Module is given in the next section. Space Vector Algorithm Now that the meaning of the variables has been given, the order in which the steps are processed during the PWM interrupt is given. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 30 Application Report SPRA588 The first step is to determine in which sector the voltage vector defined by vSαref, vSβref is found. The following few code lines give the sector as output: sector determination IF v a > 0 THEN A : =1, IF vb > 0 THEN B : =1, IF vc > 0 THEN C : =1, sec tor := A+2 B+4C ELSE A : =0 ELSE B : =0 ELSE C : =0 The second step is to calculate and saturate the duration of the two sector boundary vectors application as shown below: CASE sector OF t2 = Y 1 t1 = Z 2 t1 = Y t2 = − X 3 t1 = − Z t2 = X 4 t1 = − X t2 = Z 5 t1 = X t 2 = −Y 6 t1 = −Y t 2 = −Z end times calculation Saturations IF (t1 + t 2 ) > PWMPRD THEN t1SAT = t1 t 2 SAT = t 2 PWMPRD t1 + t 2 PWMPRD t1 + t 2 The third step is to compute the three necessary duty cycles. This is shown below: PWMPRD − t1 − t 2 t = aon 2 t bon = t aon + t1 t = t + t con bon 2 The last step is to assign the right duty cycle (txon) to the right motor phase (in other words, to the right CMPRx) according to the sector. The table below depicts this determination. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 31 Application Report SPRA588 Figure 17. Table Assigning the Right Duty Cycle to the Right Motor Phase Sector Phase 1 2 3 4 5 6 CMPR1 tbon tbaon CMPR2 taon tcon taon tcon tcon tbon tbon tbon taon tcon CMPR3 tcon tbon tcon taon tbon taon Figure 18 shows an example of one vector that would be in sector 3. Figure 18. Sector 3 PWM Patterns and Duty Cycles CMPR3 tcon CMPR2 tbon taon CMPR1 t PWM1 t PWM3 t PWM5 T0/4 T6/2 T6/2 T0/4 T0/4 T6/4 T4/4 T0/4 V0 V6 V4 V7 V7 V6 V4 V0 t T Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 32 Application Report SPRA588 Event Manager Configuration This section describes how to program the TMS320F240 peripherals in order to handle the space vector module. TIMER1 is the time base of the PWM interrupts generation. It is configured in up-down counting mode to generate the symmetrical PWM patterns. Its frequency is set at 16kHz. PWMPRD .set 258h splk #PWMPRD,T1PER splk #0,T1CNT splk #0A800h,T1CON ;PWM Period T=2*600*50ns=60us ;Set PWM interrupt period ;Ignore Emulation suspend ;Up/Down count mode ;x/1 prescalar ;Use own TENABLE ;Disable Timer ;Internal Clock Source ;Reload Compare Register when T1CNT=0 ;Disable Timer Compare operation The Timer 1 control register T1CON is programmed in order to get a 50ns resolution : the prescalar clock of the timer is set to 1 giving the highest possible resolution. The individual T1 General Purpose Compare register is reloaded every PWM cycle but not used in this application. For this reason, the General Purpose Control Register (GPTCON) is left to its default value. In fact, the only Compare registers used are the 3 Full Compare registers associated to TIMER1. These 3 Full Compare registers are controlled by the Compare Control register (COMCON). This register is programmed as follow: splk #0207h,COMCON ;Reload Full Compare when T1CNT=0 ;Disable Space Vector ;Reload Full Compare Action when T1CNT=0 ;Enable Full Compare Outputs ;Disable Simple Compare Outputs ;Select GP timer1 as time base ;Full Compare Units in PWM Mode splk #8207h,COMCON ;enable compare operation The Full Compare registers are updated at the end of the PWM interrupt routine with the calculated values taon, tbon, tcon . The output of the Compare operation are not directly sent to the Output Logic but are previously passed through the PWM Deadband on-chip circuit. Depending on the power bridge pre-driver used, the control register DBTCON has to be programmed. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 33 Application Report SPRA588 In this application, an IR2130 from International Rectifier has been used and no deadband time has been programmed because this chosen pre-driver has already an internal deadband time. splk #0000h,DBTCON ;no dead band Once the deadband unit has been passed, the signals are sent to the Output Logic (see TMS320C24x Vol2 User’s Guide page 2-46) that activates the DSP PWM pins. The polarity of the PWM pins is chosen in the Full Compare Action Control Register (ACTR) as follow: ldp #DP_EV splk #0666h,ACTR ;Bits 15-12 not used, no space vector ;PWM compare actions ;PWM5/PWM6 - Active Low/Active High ;PWM3/PWM4 - Active Low/Active High ;PWM1/PWM2 - Active Low/Active High The PWM pins are paired to control the high side and the low side of the pre-driver. PI Regulators The PI (Proportional-Integral) regulators are implemented with output saturation and with integral component correction. The constants Ki, Kpi, Kcor (proportional, integral and integral correction components) have been experimentally determined using the Graphic User’s interface (option 5 and 6). Their theoretical determination (root locus and pole placement) is beyond the scope of this report. For this application, the current regulator parameters are: Ki . Kpi Kcor . 0.03ó07Ah 0.60ó999h 0.05ó0cch The speed regulators parameters are: Kispeed 0.03ó7ah Kpispeed 6.5ó06800h Kcorspeed 0.0046ó12h All constants are in Q12 format and the integral correction component is calculated by using the formula Kcor = Ki/Kpi. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 34 Application Report SPRA588 Interface Modules The interface modules are low level routines that convert real wold data into their suitable numerical counterparts. The interface modules described are: r Current sensing and scaling r Mechanical position sensing and scaling r Electrical position and mechanical speed scaling The Sensing modules handle directly the hardware interface and dialog via the integrated TMS320F240 peripherals. The Scaling modules transform the information into a fixed-point representation related to a Per Unit model Current Sensing Module This module handles the conversion of the 3 stator phase currents into their basic binary representation. Two LEMs (current-voltage transducer) sense the phase currents. They convert the current information into voltage information. These voltages are sampled and converted by the TMS320F240 Analog to Digital Converter and stored in the variable ia and ib. Hardware Solution Figure 19 represents the hardware interface put in place to realize the described function. Figure 19. Current Sensing Hardware -2.5V Ia +15V 10K 10K 100R -15V +15V Z lem 10K ADCIN0 Vlem -15V Vadc Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 35 Application Report SPRA588 The selected ADC inputs pins are ADCIN0 for phase a and ADCIN8 for phase b. As those pins are shared (multiplexed) with general purpose IO pins, the Output Control Register A (OCRA) will be set up to select the ADC input functionality. The LEM converts the current information from phase a and b into a voltage information (Vlem) Ia and Ib are in the range +/-10A A second translation is performed in two steps in order to adapt Vlem to the TMS320F240 ADC input voltage specification: First, a gain is applied to Vlem in order to get an intermediate voltage in the range [-2.5v , +2.5V]. Then, a voltage shift of 2.5V is applied to meet the [0,5V] input range of the ADC. The voltages Vadcin0 and Vadcin8 are sample and converted by the dual 10 bit ADC. The result of the conversion is stored in binary format in the variables ia and ib. Sensing Scale Translation Figure 20 represents the correspondence between the stator phase currents and their binary representations: Figure 20. Current Sensing Scale Translation phase current binary representation ia, ib +10A 0A -10A Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 1024 512 0 36 Application Report SPRA588 Associated Low-Level Software Initialization Module As the TMS320F240 A-to-D converter is made of commuted capacitors, the ADC clock has to be defined according to the global clock (CPUCLK) and divided by a factor of prescaler. All the internal clocks are derivated form CPUCLK and the oscillator used on the Evaluation Module is a 10MHz one. CPUCLK of 20 MHz (50ns) is created by this oscillator associated to the internal PLL as follows. ***************************************** * Initialization of the TMS320F240 Clocks ***************************************** splk #00000010b,CKCR0;PLL disabled ;LowPowerMode0 ;ACLK enabled ;SYSCLK 5MHz splk #10110001b,CKCR1;10MHz CLKIN ;Do not divide PLL ;PLL ratio x2 (CPUCLK=20MHz) splk #10000011b,CKCR0;PLL enabled ;LPM0 ;ACLK enabled ;SYSCLK 10MHz The system clock (SYSCLK) had been set to 10Mhz. Setting the prescaler to 10 gives an ADC clock of 1 MHz. The 2-level deep FIFOs are emptied. **************************************************************** * A/D initialization **************************************************************** ldp #DP_PF1 splk #0003h,ADC_CNTL2;prescaler set for a 10MHz oscillator lacc ADC_FIFO1 lacc ADC_FIFO1 lacc ADC_FIFO2 lacc ADC_FIFO2 ;empty FIFO Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 37 Application Report SPRA588 To select the pins ADCIN0 and ADCIN8, the internal pin multiplexer controlled by the Output Control Register A (OCRA) is programmed as follows. **************************************************************** * Configure function of IO/MUXed shared pins **************************************************************** ldp #DP_PF2 splk #0009h,OPCRA ;ADCIN0 and ADCIN8 selected, all other are GPIO Interrupt Module Once that the AtoD Converter is correctly set, it will be used during every PWM interrupt to sample and convert the stator phase currents. A conversion is done as follows. **************************************************************** * Current sampling - AD conversions * only the 10 Least Significant bits are relevant **************************************************************** ldp #DP_PF1 splk #1801h,ADC_CNTL1 ;ia and ib conversion start ;ADCIN0 selected for ia A/D1 ;ADCIN8 selected for ib A/D2 conversion bit ADC_CNTL1,8 bcnd conversion,tc lacc ADC_FIFO1,10 ldp #ia sach ia ldp #DP_PF1 lacc ADC_FIFO2,10 ldp #ib sach ib ;wait end of Conversion The TMS320F240 integrated ADC converts simultaneously ia and ib. The result of this conversion lays in the 10 upper bits of the ADC FIFOs. Therefore a left shift of 10 bit is performed to obtain the result of the conversion in the upper word of the accumulator. Care must be taken when the sign extension mode is on (SXM = 1), the FIFO values greater than 512 (bit b15 of FIFO equal to 1) will propagate a negative sign to the upper accumulator bits. Therefore, in the Current Scaling module, the upper bits of the accumulator are masked to keep the binary representation of the variables as follows. ldp #ia lacc ia and #3ffh ;mask upper bits Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 38 Application Report SPRA588 Adaptation to Specific Cases In this particular application, a LEM was used to measure the phase current. A lower cost solution would consist in a simple shunt resistor as current sensor. This possibility has been studied in the application report [7]. Current Scaling Module The problem is to find a scaling factor K that makes the correspondence between the binary representation of the currents and their Q12 representation associated to the PU model of the currents. Scale Change Figure 21 depicts the scale changes needed to translate the binary representation of a current into its Per Unit Q12 representation. Figure 21. Scaling Factor Representation binary representation ia, ib phase current p.u current +10A 512 4.1A (Ibase) 0 p.u current in Q12 2.439 1 2706h 1000h 0 0A 0 *K ? i binary -512 Current Sensing -10A ÷ Ibase ipuQ12 -2.439 *2 12 D8FAh Current Scaling First, the binary representation of the current is modified in this module. An offset of 512 has been subtracted to contradict the analog offset of 2.5V that was previously introduced. +10A is now represented in binary by +512 and –10A by -512. The problem here is the opposite of the one from the Sensing module. Now, given a binary representation of a current, the goal is to find a real number corresponding to the Per Unit value of the current. In other words, the aim of the translation is to find a factor K such as : ipuQ12 = ibinary * K For ibinary = 512, ipuQ12 = (Imax/Ibase) * 212 = 2.439*4096 = 9990 Then : K= ipuQ12 / ibinary = 9990/512 = 19.51 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 39 Application Report SPRA588 K has been determined by knowing the maximal value (10A corresponds to 512). It can also be determined from base values as follow: Ibase= 4.1A corresponds to the binary representation 210 (D2h) For ibinary = 210, ipuQ12 = (Ibase/Ibase) * 212 = 4096 Then K = 4096/210 ≅ 19.51 This method will be preferred to calculate translation factors knowing the base values. Note that K is outside the Q12 dynamic range. The most appropriate format to accommodate this constant is the Q8 format. In the application software, the constant K is called Kcurrent and its representation in Q8 is given by: Kcurrent = 19.51 ó1383h (Q8). Translation Routine The following routine performs the translation from the binary representation of the currents into their Per Unit Q12 format. ********************************************* * Sampled current scaling * ********************************************* ldp #ia lacc ia and #3ffh ;mask upper bits sub #512 ;subtract the offset (2.5V) to have ;positive and negative values of the current sacl tmp spm 3 lt tmp mpy Kcurrent pac sfr sfr sacl ia ;current ia, f 4.12 in PU As previously mentioned, an offset of 512 is subtracted to the representation coming from the sensing. The result of this subtraction is stored in a temporary variable called tmp. One of the most important point is to correctly tune this subtracted offset. In the FOCPMSM.ASM program, a SUB #440 is done instead of the SUB #512 instruction. The next step is to multiply to multiply tmp by the scaling factor Kcurrent. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 40 Application Report SPRA588 The multiplication performed here is not as obvious as in base 10 representation of numbers. The problem is that the DSP is not able to perform directly the multiplication of a binary by a real number (19.51) as it is a fixed-point device. The real operation performed is to multiply tmp by the Q8 fixed-point representation of Kcurrent. For example, when the binary number tmp is 210 (corresponding to the nominal current), the multiplication in base 10 would be: 210 * 19.51 ≈ 4097 (0x1001h) represents 1 in Q12 format As it is not possible to multiply directly by 19.51, the real multiplication performed is: 210* (19.51*28) = 210 * 4994 The last operation is to retrieve the value of ipuQ12 from this multiplication. To do so, the result of the multiplication is right shifted eight times which corresponds to a division by 28 (the instruction ”spm 3” performs 6 right shifts and two sfr complete the 2 right shifts). Adaptation to Specific Cases According to your specific motor characteristics (Nominal phase current) or the specific precision wanted (Qk format), it might be necessary to adapt the K scaling factor. current For example, if the nominal phase current of the machine is 3.6A, the base value is 5.1A (and 261 its binary representation) then Kcurrent = 4096 / 261 = 15.69 ó 0FB1h (Q8). If the Q12 precision doesn’t fit the user’s specific application (transient currents not greater than two times the nominal currents), a more precise format can be chosen. For example in the case of a 10bit ADC with a 3.6A of nominal current and a Q13 representation, Kcurrent would be: Kcurrent = 8192 / 210 = 39.00. The other important point already mentioned is to tune the offset of the current measurement. You must adjust this offset to obtain sinusoidal stator currents. If the stator currents are wrongly interpreted in the software, the performance of the drive will be poor. Mechanical Position Sensing and Scaling Module This module converts the number of pulses sent by the incremental encoder into an absolute mechanical position of the rotor shaft. The absolute mechanical position will be stored in the variable θm. It is possible to obtain an absolute mechanical position with the incremental encoder by physically locking the rotor in a known position. This stall is done in the start-up procedure. A zero is written in the encoder counter register thereby referencing the mechanical position to the locked position. The number of encoder pulses detected between two PWM period is stored in the variable called “encincr”. These variables will be used afterwards to determine the electrical position of the rotor and the mechanical speed of the rotor in dedicated scaling modules. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 41 Application Report SPRA588 Hardware Solution The photo sensors of the encoder (Figure 22) are activated by the light of an internal LED. When the light is hidden, the sensor sends a logical “0”. When the light passes through one of the 1024 slots of the encoder, a logical “1” is sent. Two photo sendlogical information on Channel A and Channel B. The TMS320F240 on-chip QEP (Quadrature Encoder Pulse) detects the rising and falling edges of both channels. The count of the edges detected by the QEP is stored in the counter T3CNT. This counter is in fact related to the timer T3 that is automatically clocked by the QEP pulses when the QEP mode is selected. Figure 22. Incremental Optical Encoder sensor slots 2 led A B The embedded encoder of this application generates 1024 pulses per mechanical revolution. Every slot generates 4 edges : 1 rising and 1 falling edge for both channels A and B. These edges are detected by the QEP, meaning that 4096 edges are detected per mechanical revolution. The QEP detects also the sense of rotation of the rotor shaft depending on the leading sequence (if Channel A signal are in advance or delayed compared to Channel B). The number of edges is stored in T3CNT. Depending on the sense of revolution, T3CNT is incremented or decremented. Once that the QEP mode is selected, the Timer T3 wraps automatically around a period of FFFFh. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 42 Application Report SPRA588 Sensing Scale Translation The relative mechanical angular displacement calculated between two sampling period is equal to ∆θm = T3CNT(t) - T3CNT(t - ∆t ) * 360° , where Encpulses is here equal to EncPulses 4096. Accordingly, the absolute mechanical position is computed every sampling period as follow: θm(t)=θm(t-∆t)+∆θm It has been chosen here to represent 360° mechanical by 1000h (EncPulses). The above equation is then simplified: θm(t)=θmold+encincr with encincr = T3CNT(t)-encoderold and encoderold=T3CNT(t-∆t). A software rollover is also foreseen in case that the calculated angle exceeds 360°. This sensing scale translation can be represented by the following diagram: Figure 23. Sensing Scale PWM interrupt time mechanical angular position of the rotor (1)000h 0FFFh 360°mechanical 1h 0FFEh t3: T3CNT=1132h θm(t2) 292°mechanical θm(t1) 200°mechanical θm(t3) θm(t0) 27°mechanical 2h 3h t2: T3CNT=0CFFh t1: T3CNT=08ECh t0: T3CNT=0 0°mechanical QEP pulses detected Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 43 Application Report SPRA588 Associated low-level software routines Initialization module Both Timer3 Control register (T3CON) and Capture Unit Control register (CAPCON) are configured to enable the QEP functionality: **************************************************************** * QEP initialization **************************************************************** ldp #DP_EV splk #0000h,T3CNT ;reset counter register splk #0ffffh,T3PER ;configure period register splk #9870h,T3CON ;configure for QEP and enable Timer T3 splk #0E2F0h,CAPCON ;T3 is selected as Time base for QEP As the QEP pins are also shared with capture pins, it is necessary to set up the output control register (OCRB) to enable the QEP pins: splk #0038h,OPCRB ;QEP pins selected and IOPC3 Interrupt Module The following variables are used in the interrupt module: r encincr : increment of T3CNT between two PWM interrupts r θm : absolute mechanical position r encoderold : last T3CNT value r Encpulses : This constant is equal to four times the number of encoder pulses/mechanical rotation. *** Encoder ldp lacc ; neg ldp sacl subs sacl add sacl sub bcnd sacl encminmax lacc sacl pulses reading #DP_EV T3CNT ;read the encoder pulses ; if the encoder channels are plugged in the ; negative counting direction; #ia tmp encoderold ;increment T3CNT(k)-T3CNT(k-1) encincr teta_m ;old mechanical position teta_m ;new one #Encpulses ;soft rollover encminmax,LT ; teta_m tmp encoderold ;for next PWM ISR Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 44 Application Report SPRA588 In the above code, a software rollover is performed when the new position is greater than Encpulses to keep the value of θm in the range [0;1000h]. Notice that no software detection of the sense of rotation has been implemented. Depending on how the user wraps his two wires to the QEP inputs, a NEG instruction has to be added in order to get a positive increment in T3CNT. Adaptation to Specific Cases In this particular application, a 1024 incremental encoder was used to measure position and speed of the rotor. In the case of an encoder with a different resolution, the modifications are: change the value of the variable Encpulses and adapt the representation of 360 mechanical degrees. As previously mentioned, the user will have to add the NEG instruction, depending on how the channel A and B wires are connected to the QEP input pins. Electrical Position Scaling Module This module makes the correspondence between the relative mechanical position and the relative electrical position of the rotor. Scale Change Figure 24. Electrical Position Scaling mechanical angular position of the rotor electrical angular position of the rotor 360°mechanical 360°electrical 240°mechanical 360°electrical θm θe 120°mechanical 360°electrical 0°mechanical 0°electrical The aim of the translation is to find a scaling factor K such as K*θm = θe Given the relationship θ e = θ m* p ( p is the number of pole pair), we obtain K=3 for a three pole pairs motor. In this application, K is called Kencoder. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 45 Application Report SPRA588 Translation Routine The following routine performs the translation from the mechanical position to the electrical. ******************* * Teta calculation ******************* lt teta_m mpyu Kencoder ;multiply mechanical pos by Kencoder pac and #0fffh sacl teta_e The result of the multiplication is masked in order to have a software rollover of the electrical position when this position completed 360 electrical degrees. Adaptation to Specific Cases According to the Number of pole pairs of the motor, it might be necessary to adapt the K coefficient as follow : K =p where p is the number of pole pairs. encoder encoder Mechanical Speed Scaling Module This section presents how to relate the increment of QEP pulses that appear between two speed sampling period to the Q12 representation of the mechanical speed associated its PU model. The mechanical speed is computed periodically to provide a feedback to the PI speed regulator. The update of the speed information is not as critical as the update of the currents. The reason is that the mechanical response time constant of the system is very slow compared to the electrical one. Therefore, the mechanical speed is updated on a lower time base than the electrical quantities (updated every PWM interrupt). A software counter called speedstep is incremented by one every PWM interrupt. Once it has reached its period value SPEEDSTEP, the calculation of the mechanical speed is done, taking into account the number of QEP pulses received from the last speed computation. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 46 Application Report SPRA588 Scale Change Figure 25. Mechanical Speed Scale time PWM interrupt number of pulses counted (3000 rpm) t27 .. . mechanical speed of the rotor NpuQ12 t3 encincr2 t2 speedtmp 1000h npuQ12 encincr1 t1 encincr0 0 t0 0 rpm 0h QEP pulses The aim of the translation is to find K such as K*speedtmp = npuQ12 With: speedtmp = k = SPEEDSTEP ∑ encincr k k =0 When the software counter reaches its period called SPEEDSTEP (SPEEDSTEP=28), the time elapsed is 1.68 ms (28*60us). Base speed nbase is 3000rpm ó50 mechanical revolutions per second At base speed, the number of pulses counted by the QEP per second is 50 * 4096 = -3 204800 pulses. It means that speedtmp =204800*1.68*10 = 344 pulses Then: K= 4096/344 = 11.9069 ó BE7h in 8.8f In this application the coefficient K is called Kspeed. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 47 Application Report SPRA588 Translation Routine ******************************************************* * Calculate speed and update reference speed variables ******************************************************* lacc speedstep ;are we in speed control loop ? sub #1 ; sacl speedstep ; bcnd nocalc,GT ;if we aren't, skip speed calculation *** Speed calculation from encoder pulses lt speedtmp ;multiply encoder pulses by Kspeed ;(8.8 format constant) to have the value ;of speed mpy #Kspeed pac rpt ; ; #7 sfr ; ; sacl n ; n in PU Q12 lacc #0 ;zero speedtmp for next calculation sacl speedtmp ; lacc #SPEEDSTEP ;restore speedstep to the value ;SPEEDSTEP sacl speedstep ;for next speed control loop The result is stored in Q12 and is related to the PU model value of 3000rpm. Adaptation to Specific Cases According to your specific motor characteristics (Nominal Speed) and the specific speed sensing hardware (Encoder resolution), it might be necessary to adapt the K speed coefficient. For instance, in the case of a motor with a nominal speed of 1000 rpm, we would obtain the following K : speed K = 4096 / (16,66*4096*1.68*10-3) = 35.61 speed If the encoder resolution is 1000 pulses per revolution, we would obtain a new K speed -3 such as: K = 4096 / (50*4000**10 ) = 12.19 speed Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 48 Application Report SPRA588 Experimental Results The motor has been mounted on a test bench with adjustable resistive torque in order to test the behavior of the drive in different configurations. The DACs of the EVM are 12bit Digital to Analog converters. They have been used to output the evolution of the variables chosen by the user via the Graphic Interface. The DACs output are updated at the end of every PWM interrupt. A written value of 0FFFh (4095) represents the maximal output voltage of +5V. The value 0800h is added in the assembly code to the outputted variables to provide a virtual ground at +2.5V in order to visualize positive and negative values. Figure 26 shows the current in the stator phase A at start of rotation of the rotor. The left side of the figure is given without resistive torque applied whereas the right side of the figure is given with a resistive torque of 1Nm. Figure 26. Transient Stator Phase A Current Ch4: stator phase current ia In Figure 26, it can be seen that the rotor has been first stalled by applying a constant stator reference current vector. The electrical angle chosen for this reference vector is –90 electrical degrees which corresponds physically to apply all the current to the stator phase a. The two other phases are the return paths for this current. In this stalled mode, it can be seen that the current is correctly regulated to the nominal value, meaning that the fed current is controlled in amplitude. This control of the phase currents prevent the motor from heating. Once the motion is started, the current fed to the phases depends on the resistive torque load applied to the rotor. In the case of no resistive torque, the steady-state currents are quasi null. In the case of the maximal resistive torque applied (2.2 Nm), the steady-state currents in the phases are equal to the nominal current (4.1A). Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 49 Application Report SPRA588 Figure 27. Transient Currents isd, isq at Start Ch1: isq : current vector q projection (torque control) Ch2: isd : current vector d projection (rotor flux control) Ch4: ic : real stator phase c current Figure 27 shows the behavior of the calculated current projections at start. The reference speed is set to 500 rpm and no resistive torque is applied. The isd and isq projections are outputted on the DAC and their values are updated every PWM interrupt. Current spikes appear in the picture. These spikes are due to the +90 electrical degrees shift of the stator current vector. The currents in the coils do not disappear instantaneously due to the electrical time constant of the motor. A certain amount of time is necessary to apply a new stator current vector that is +90° apart from the initial one. The isd and isq current regulators act to reduce the error between the projections and the reference currents. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 50 Application Report SPRA588 Figure 28. Speed Transient from 0 to 1000 rpm Figure 28 shows the behavior of the stator currents at start with a resistive torque load of 1 Nm. Ch1 : n : mechanical speed Ch1 : isq : torque control component Ch2 : ib stator phase current Ch2 : ib stator phase current Ch4 : ia stator phase current Ch4 : ia stator phase current It can be seen that when the motion starts, the torque control component isq is equal to the maximal authorized value. This maximal value is controlled by the isq PI current regulator and is equal to 1.1 of the PU model (10% more than the current base value is authorized). The amplitude of the stator phase currents are by the way always under control. Table 4 relates the behavior of the motor under different loads at 500rpm and Table 5 at 1500rpm. Table 4. Motor at 500 rpm Torque Nm 0.1 0.5 1 1.5 2 2.2 2.3 Power W 5 25 50 76 102 113 119 The progression of the ratio power/torque is linear until the nominal torque. With a torque exceeding the nominal torque, the motor stalls. Table 5. Motor at 1500 rpm Torque Nm 0.1 0.5 1 1.5 2 2.2 2.3 Power W 15 78 157 234 311 344 358 The progression of the ratio power/torque is also linear until the nominal torque. At nominal speed (3000rpm) the maximal power reached was 640W under nominal torque (2.2Nm). Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 51 Application Report SPRA588 User Interface This section presents the screen picture that has been used as user interface. The corresponding Quick Basic program and the assembly communication software are given in Appendix. Below is a copy of the screen picture. The top part of the Interface is dedicated to the six possible user commands. r Selection of the mechanical speed reference <1> r Selection of the outputted variables on the four DACS <2> r Start the motion <3> r Select the DC bus voltage (not used) r Adjust the PI current controllers experimentally r Adjust the PI speed controllers experimentally The bottom part of the Interface corresponds to the choice of the variables to be outputted by the on-board 4 DACs. The DACs will output the real-time values of the variables every PWM interrupts. This feature is very useful during debugging or benchmarking phases. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 52 Application Report SPRA588 Software Modularity In this report, the software modules have been divided into blocks of codes that can be tuned individually. In order to ease the debug phase and individual module benchmarks, software switches have been added into the FOC algorithm. These switches consist of conditionnal assembly statements and thus induce no overhead in the execution time of the program. The list of the individual module switches is given below: *** Software switches *** interrupt_module .set 1 current_sensing .set 1 current_scaling .set 1 clarke .set 1 park .set 1 inv_park .set 1 isq_regulator .set 1 isd_regulator .set 1 speed_regulator .set 1 svpwm .set 1 sine_table .set 1 position_sensing .set 1 position_scaling .set 1 speed_scaling .set 1 virtual_menu .set 1 You can then select specific parts of the code to be assembled for test. When the switch is set to 0, the assembler doesn’t take into account the block of code comprised between the .if switch and .endif statements. Therefore, the ADC conversion can be tested or the Space Vector Modulation without having to test the rest of the algorithm. A special switch has been defined in order to allow the user to run the program without having to use the Graphical User Interface. This switch is called “virtual_menu”. When virtual_menu is set to 0, a magnetic stall is performed until a software counter is decremented to 0 (stall_timer1, stall_timer2), then the motor is started with its nominal speed reference (3000 rpm). Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 53 Application Report SPRA588 Conclusion The FOC control routine takes an average of 27.5 us for execution. The amount of program memory used for the whole program is lower than 1Kword. More details are given in the following tables: The amount of memory used by this application is given in the following table: Program Memory Used Data Memory Used Flash : 988 words (of the 16K) B0 : 69 words (of the 256 available) B1 : 256 words (of 256) B2 : 25 words (of 32) The timing benchmarks for the modules are given below: Software Module CPU cycles Time Current sensing Current scaling Park transform Clarke transform -1 Clarke transform Motion sensing Sine, Cosine calculation Regulators (d,q, speed) Space Vector PWM 151 31 9 14 14 19 32 34 * 3 166 7.55 us 1.55 us 0.45 us 0.7 us 0.7 us 0.95 us 1.6 us 5.1 us 8.3 us TOTAL 538 26.9 us The conversion time of the TMS320F240 is about 6.6 us (ia and ib are converted simultaneously). The new family of DSPs (TMS320F241, F243) have faster ADCs with 850ns conversion time for each current phase (1.7us to convert ia and ib). It has been shown that the Field Oriented Control is a powerful algorithm that enables a real time control of the torque without ripples and stator phase currents amplitudes are always under control. The space vector algorithm is especially suited to generate the voltage references in co-ordination with the FOC. Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 54 Application Report SPRA588 References 1. Texas Instruments, Field Orientated Control of Three phase AC-motors, (BPRA073), December 1997. 2. Texas Instruments, DSP Solution for Permanent Magnet Synchronous Motor, (BPRA044), Nov. 1996. 3. Texas Instruments, Clarke & Park Transforms on the TMS320C2xx, (BPRA048), Nov. 1996. 4. T.J.E. Miller, Brushless Permanent-Magnet and Reluctance Motor Drives, Oxford Science Publications, ISBN 0-19-859369-4. 5. Riccardo Di Gabriele, Controllo vettoriale di velocità di un motore asincrono mediante il Filtro di Kalman Esteso, Tesi di Laurea, Università degli Studi di L’Aquila, Anno Accademico 1996-97 6. Roberto Petrella, Progettazione e sviluppo di un sistema digitale basato su DSP e PLD per applicazione negli azionamenti elettrici, Tesi di Laurea, Università degli Studi di L’Aquila, Anno Accademico 1995-96 7. Texas Instruments, 3-phase Current Measurements using a Single Line Resistor on the TMS320F240 DSP, (BPRA077), May 1998. 8. Guy Grellet, Guy Clerc, Actionneurs electriques, Eyrolles, Nov 1996. 9. Jean Bonal, Entrainements electriques a vitesse variable, Lavoisier, Jan 1997. 10. Philippe Barret, Regimes transitoires des machines tournantes electriques, Eyrolles, Fev. 1987 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 55 Application Report SPRA588 Software Variables The following list shows the different variables used in this control software and in the equations and schemes presented here. ia, ib, ic stator phase currents isα, isβ stator current (α,β) components isd, isq stator current flux & torque components isdref, isqref flux and torque command θe rotor flux electrical position θm rotor flux mechanical position Vsdref, Vsqref (d,q) components of the reference stator voltage Vsαref, Vsβref (α,β) components of the stator reference voltage VDC DC bus voltage VDCinvT constant using in the SVPWM Va, Vb, Vc (a,b,c,) components of the stator reference voltage sector sector variable used in SVPWM t1, t2 time vector application in SVPWM taon, tbon, tcon PWM commutation instant X, Y, Z SVPWM variables n, nref speed and speed reference isqrefmin, isqrefmax speed regulator output limitation Vmin, Vmax d,q current regulator output limitation Ki, Kpi, Kcor current regulator parameters Kispeed, Kpispeed, Kcorspeed speed regulator parameters xid, xiq, xispeed regulator integral components epid, epiq, epispeed d,q-axis, speed regulator errors Kspeed 4.12 speed formatting constant Kcurrent 4.12 current formatting constant Kencoder 4.12 encoder formatting constant SPEEDSTEP speed loop period speedstep speed loop counter encincr encoder pulses storing variable speedtmp occurred pulses in SPEEDSTEP sin, cos sine and cosine of the rotor flux position Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 56 Application Report SPRA588 Appendix A. TMS320F240 FOC Software **************************************************************** * TEXAS INSTRUMENTS * * Implementation of a Speed Field Orientated Control* * of 3phase PMSM motor using the TMS320F240 * * * **************************************************************** * File Name: focpmsm.asm * * Originator: Erwan SIMON * * Description: PMSM Speed field oriented control * * DSP development platform : TI TMS320F240 Evaluation Module * * Power board : IR2130 demo board * * Motor : Digiplan MD3450 * * * * Last modified: 28/07/1999 * **************************************************************** * Auxiliary Register used * * ar4 pointer for context save stack * * ar5 used as general purpose table pointer * **************************************************************** .include ".\c240app.h" **************************************************************** * Interrupt vector table * **************************************************************** .global _c_int0 _c_int1 stack dac_val sintab .sect "vectors" b _c_int0 ;reset vector b _c_int1 b _c_int2 ; PWM interrupt handler .usect "blockb2",15 ;space for ISR indirect context save .usect "blockb2",5 ;space for dac values in Page 0 .sect "table" .include sine.tab ;sine wave look-up table for sine and cosine waves generation ;4.12 format **************************************************************** * Variables and constants initializations **************************************************************** .data *** current sampling constants Kcurrent .word 01383h ;8.8 format (*19.5) sampled currents normalization constant ;ADCIN0 (ia current sampling) ;ADCIN8 (ib current sampling) *** axis transformation constants SQRT3inv .word 093dh ;1/SQRT(3) 4.12 format SQRT32 .word 0ddbh ;SQRT(3)/2 4.12 format *** PWM modulation constants .bss _v_meas,1 PWMPRD .set 258h ;PWM Period=2*600 -> Tc=2*600*50ns=60us (50ns ; resolution) Tonmax .set 0 ;minimum PWM duty cycle MAXDUTY .set PWMPRD-2*Tonmax ;maximum utilization of the inverter Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 57 Application Report SPRA588 *** PI current regulators parameters Ki .word 07Ah ;4.12 Kpi .word 999h ;4.12 Kcor .word 0cch ;4.12 ;Kcor *** PI speed regulators parameters Kispeed .word 7ah ;4.12 Kpispeed .word 06800h ;4.12 Kcorspeed .word 12h ;4.12 *** Vqr and Vdr limitations Vbase .set 01000h Vmin .set 0ec00h Vmax .set 01400h *** Is and Idr limitations ismax .word 01199h iSdrefmin .set 0ee67h iSdrefmax .set 00000h zero .word 0h *** Initialization phase Iqr iSqrefinit .set 01000h format = 0.03 format = 0.60 (include period) format = 0.05 = Ki/Kpi format = 0.03 format = 6.5 format = 0.0046 ;BEMF at base speed ;4.12 format = -1.25 pu ;4.12 format = 1.25 pu ;4.12 format = 4.51A Inominal+10%, ;4.12 format = -4.51A (1000h = Ibase) ;4.12 format = 0A (1000h = Ibase) ;4.12 format = 4.1A (1000h = Ibase) *** Encoder variables and constants Kencoder .word 3 ;this constant is used to convert encoder pulses ;[0;4095] to an electric angle [0;360]=[0000h;1000h] Encpulses .set 4096 ;number of encoder pulses per mechanical ;revolution *** Speed and estimated speed calculation constants Nbase .set 1000h ;Base speed Kspeed .set 0be7h ;used to convert encoder pulses to a speed value ;8.8 format = 11.9 (see manual for details about ;this constant calculation) ;base speed 3000rpm, PWMPR 258h SPEEDSTEP set 28 ;speed sampling period = current sampling period * 40 *** Speed and estimated speed calculation constants .bss tmp,1 ;temporary variable (to use in ISR only !!!) .bss option,1 ;virtual menu option number .bss daout,1 ;address of the variable to send to the DACs .bss daouttmp,1 ;value to send to the DACs *** DAC displaying table starts here .bss ia,1 ;phase current ia .bss ib,1 ;phase current ib .bss ic,1 ;phase current ic .bss Ua,1 ; (not used) .bss Ub,1 ; (not used) .bss Uc,1 ; (not used) .bss sin,1 ;generated sine wave value .bss t1,1 ;SVPWM T1 (see SV PWM references for details) .bss t2,1 ;SVPWM T2 (see SV PWM references for details) .bss cos,1 ;generated cosine wave value .bss Va,1 ;Phase 1 voltage for sector calculation .bss Vb,1 ;Phase 2 voltage for sector calculation .bss Vc,1 ;Phase 3 voltage for sector calculation .bss VDC,1 ;DC Bus Voltage .bss taon,1 ;PWM commutation instant phase 1 .bss tbon,1 ;PWM commutation instant phase 2 .bss tcon,1 ;PWM commutation instant phase 3 .bss teta_e,1 ;rotor electrical position in the range [0;1000h] ;4.12 format = [0;360] degrees Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 58 Application Report SPRA588 .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss *** END DAC iSalfa,1 ;alfa-axis current iSbeta,1 ;beta-axis current vSal_ref,1 ;alfa-axis reference voltage vSbe_ref,1 ;beta-axis reference voltage iSdref,1 ;d-axis reference current iSqref,1 ;q-axis reference current iSd,1 ;d-axis current iSq,1 ;q-axis current vSdref,1 ;d-axis reference voltage vSqref,1 ;q-axis reference voltage epiq,1 ;q-axis current regulator error epid,1 ;d-axis current regulator error xiq,1 ;q-axis current regulator integral component xid,1 ;d-axis current regulator integral component n,1 ;speed n_ref,1 ;speed reference epispeed,1 ;speed error (used in speed regulator) xispeed,1 ;speed regulator integral component X,1 ;SVPWM variable Y,1 ;SVPWM variable Z,1 ;SVPWM variable sectordisp,1 ;SVPWM sector for display initphase,1 ;flag for initialization phase teta_m,1 Vr,1 ;(not used) iSqrefmin,1 ;iSq min limitation iSqrefmax,1 ;iSq max limitation displaying table .bss .bss .bss .bss .bss .bss .bss .bss .bss .bss sector,1 serialtmp,1 da1,1 da2,1 da3,1 da4,1 VDCinvT,1 index,1 upi,1 elpi,1 ;SVPWM sector ;serial communication temporary variable ;DAC displaying table offset for DAC1 ;DAC displaying table offset for DAC2 ;DAC displaying table offset for DAC3 ;DAC displaying table offset for DAC4 ;used in SVPWM ;pointer used to access sine look-up table ;PI regulators (current and speed) output ;PI regulators (current and speed) limitation error .bss .bss .bss tmp1,1 accb,2 acc_tmp,2 ;tmp word ;2 words buffer ;2 words to allow swapping of ACC .bss encoderold,1 ;encoder pulses value stored in the previous ;sampling period .bss encincr,1 ;encoder pulses increment between two ;consecutive sampling periods .bss speedtmp,1 ;used to accumulate encoder pulses increments ;(to calculate the speed each speed sampling period) .bss speedstep,1 ;sampling periods down counter used to ;define speed ;sampling period *** END Variables and constants initializations *** Software switches interrupt_module current_sensing current_scaling clarke park inv_park isq_regulator isd_regulator *** .set 1 .set 1 .set 1 .set 1 .set 1 .set 1 .set 1 .set 1 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 59 Application Report SPRA588 speed_regulator svpwm sine_table position_sensing position_scaling speed_scaling .set 1 .set 1 .set 1 .set 1 .set 1 .set 1 virtual_menu .set 1 .bss stall_timer1,1 .bss stall_timer2,1 .text **************************************************************** * Initialisation Module * **************************************************************** _c_int0: **************************** * C2xx core general settings **************************** clrc CNF ;set Block B0 as Data RAM (default) setc OVM ;saturate when overflow spm 0 ;no accumulator shift after multiplication setc sxm ;sign extension mode on **************************************************************** * Initialize ar4 as the stack for context save * space reserved: DARAM B2 60h-80h (page 0) **************************************************************** lar ar4,#79h lar ar5,#60h **************************************************************** * Disable the watchdog timer * **************************************************************** ldp #DP_PF1 splk #006Fh, WD_CNTL splk #05555h, WD_KEY splk #0AAAAh, WD_KEY splk #006Fh, WD_CNTL ***************************************** * Initialization of the TMS320F240 Clocks ***************************************** splk #00000010b,CKCR0;PLL disabled ;LowPowerMode0 ;ACLK enabled ;SYSCLK 5MHz splk #10110001b,CKCR1;10MHz CLKIN ;Do not divide PLL ;PLL ratio x2 (CPUCLK=20MHz) splk #10000011b,CKCR0;PLL enabled ;LPM0 ;ACLK enabled ;SYSCLK 10MHz splk #40C0h,SYSCR ;Set up CLKOUT to be SYSCLK ***************************************** * F240 specific control register settings ***************************************** ; reset system control register lacc SYSSR and #69FFh sacl SYSSR **************************************************************** * A/D initialization **************************************************************** splk #0003h,ADC_CNTL2;prescaler set for a 10MHz oscillator lacc ADC_FIFO1 ;empty FIFO Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 60 Application Report SPRA588 lacc ADC_FIFO1 lacc ADC_FIFO2 lacc ADC_FIFO2 **************************************************************** * Serial communication initialization **************************************************************** splk #00010111b,SCICCR ;one stop bit, no parity, 8bits splk #0013h,SCICTL1 ;enable RX, TX, clk splk #0000h,SCICTL2 ;disable SCI interrupts splk #0000h,SCIHBAUD ;MSB | splk #0082h,SCILBAUD ;LSB |9600 Baud for sysclk 10MHz splk #0022h,SCIPC2 ;I/O setting splk #0033h,SCICTL1 ;end initialization **************************************************************** * PWM Channel enable * 74HC541 chip enable connected to IOPC3 of Digital input/output **************************************************************** ; Configure IO\function MUXing of pins ldp #DP_PF2 ;Enable Power Security Function splk #0009h,OPCRA ;Ports A/B all IO except ADCs splk #0038h,OPCRB ;Port C as non IO function except IOPC0&3 splk #0FF08h,PCDATDIR;bit IOPC3 **************************************************************** * Incremental encoder initialization **************************************************************** ldp #DP_EV splk #0000h,T3CNT ;configure counter register splk #0ffffh,T3PER ;configure period register splk #9870h,T3CON ;configure for QEP and enable Timer T3 splk #0E2F0h,CAPCON ;T3 is selected as Time base for QEP ******************************************** * Wait state generator init ******************************************** ldp #ia splk #04h,tmp out tmp,WSGR *************************************************************** * Variables initialization **************************************************************** ldp #ia lacc ismax sacl iSqrefmax neg sacl iSqrefmin zac sacl iSqref sacl iSdref sacl n_ref sacl iSdref sacl index sacl xid sacl xiq sacl xispeed sacl upi sacl elpi sacl Va sacl Vb sacl Vc sacl initphase sacl da1 lacc #1 sacl da2 lacc #2 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 61 Application Report SPRA588 sacl lacc sacl splk da3 #3 da4 #015Ch,VDCinvT splk #07FFFh,stall_timer1 splk #07FFFh,stall_timer2 ***************************************** * Event manager settings ***************************************** ldp #DP_EV splk #0666h,ACTR ;Bits 15-12 not used, no space vector ;PWM compare actions ;PWM5/PWM6 - Active Low/Active High ;PWM3/PWM4 - Active Low/Active High ;PWM1/PWM2 - Active Low/Active High splk #300,CMPR1 ;no current sent to the motor splk #300,CMPR2 splk #300,CMPR3 splk #0000h,DBTCON ;no dead band splk #0207h,COMCON ;Reload Full Compare when T1CNT=0 ;Disable Space Vector ;Reload Full Compare Action when T1CNT=0 ;Enable Full Compare Outputs ;Disable Simple Compare Outputs ;Select GP timer1 as time base ;Full Compare Units in PWM Mode splk #8207h,COMCON ;enable compare operation splk splk splk #PWMPRD,T1PER #0,T1CNT #0A800h,T1CON ;Set PWM interrupt period ;Ignore Emulation suspend ;Up/Down count mode ;x/1 prescalar ;Use own TENABLE ;Disable Timer ;Internal Clock Source ;Reload Compare Register when T1CNT=0 ;Disable Timer Compare operation ; Enable Timer 1 operation lacc T1CON or #40h sacl T1CON **************************************************************** * Enable PWM control Interrupt **************************************************************** ; Clear EV IFR and IMR regs splk #07FFh,IFRA splk #00FFh,IFRB splk #000Fh,IFRC ; Enable T1 Underflow Int splk #0200h,IMRA splk #0000h,IMRB splk #0000h,IMRC ;Set IMR for INT2 ldp #0h lacc #0FFh sacl IFR lacc #0000010b sacl IMR clrc INTM ;clear interrupt flags ;enable all interrupts Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 62 Application Report SPRA588 b menu ;branch to menu loop ******************************************************* * _c_int2 Interrupt Service Routine * synchronization of the control algorithm with the PWM * underflow interrupt ******************************************************* _c_int2: ************************ * Context Saving ************************ mar *,ar4 ;AR4 active auxiliary reg (stack pointer) mar *sst #1,*;save status register 1 sst #0,*;save status register 0 sach *;save MS word of accu sacl *;save LS word of accu * END Context Saving * mar *,ar5 ;AR5 active auxiliary reg ldp #DP_EV ;DP points to Event Manager control reg page lacc IVRA ;read the interrupt vector .if interrupt_module ControlRoutine .if current_sensing **************************************************************** * Current sampling - AD conversions * N.B. we will have to take only 10 bit (LSB) **************************************************************** ldp #DP_PF1 splk #1801h,ADC_CNTL1;ia and ib conversion start ;ADCIN0 selected for ia A/D1 ;ADCIN8 selected for ib A/D2 conversion bit ADC_CNTL1,8 bcnd conversion,tc ;wait approximatly 6us lacc ADC_FIFO1,10 ldp #ia sach ia ldp #DP_PF1 lacc ADC_FIFO2,10 ldp #ib sach ib .endif *** Initialization phase lacl initphase bcnd Run,NEQ lacc #0fc00h sacl lacc teta_e #iSqrefinit sacl lacc sacl sacl sacl sacl sacl lacc iSqref #0 iSdref teta_m encoderold n speedtmp #SPEEDSTEP ;are we in initialization phase ? ;if yes, set teta = 0fc00h 4.12 format = -90 ; degrees ;(align rotor with phase 1 flux) ; ;q-axis reference current = initialization ;q-axis reference current ; ;zero some variables and flags ; ; ; ; ; ;restore speedstep to the value SPEEDSTEP Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 63 Application Report SPRA588 sacl ldp splk speedstep #DP_EV #0,T3CNT ldp b #initphase Init Run .if ; for next speed ;control loop ; ;zero Incremental Encoder value if ;initialization step ;there is no need to do position and ;calculation ;in initialization phase (the rotor is locked) position_sensing *** Encoder ldp lacc neg ldp sacl sub sacl add bcnd add encmagzero sacl pulses reading #DP_EV T3CNT ;we read the encoder pulses and ... ;encoder plug in the opposite direction ? #ia tmp encoderold ;subtract the previous sampling period value ;to have the increment that we'll ;accumulate in encoder encincr ; teta_m ; encmagzero,GT,EQ;here we start to normalize teta_m ; value to the range [0;Encpulses-1] #Encpulses ;the value of teta_m could be negative ;it depends on the rotating direction ;(depends on motor windings ;to PWM Channels connections) teta_m sub #Encpulses bcnd sacl encminmax,LT teta_m encminmax lacc tmp sacl .endif encoderold ;now teta_m value is positive but could be ;greater than Encpulses-1 ;we subtract Encpulses and we check whether ;the difference is negative. If it is we ;already have the right value in teta_m ; ;otherwise the value of teta_m is greater ;than Encpulses and so we have to store the ;right value ok, now teta_m contains the ; right value in the range ;[0,Encpulses-1] ;the actual value will be the old one during ; the next sampling period .if position_scaling ******************* * Teta calculation ******************* lt teta_m ;multiply teta_m pulses by Kencoder (4.12 ;format constant) to have the rotor ;electrical position mpyu Kencoder ;encoder pulses = 0 -> teta = 0fffh = 0 degrees pac ;encoder pulses = 1600 -> teta = 1fffh = 1*360 ;encoder pulses = 3200 -> teta = 2fffh = 2*360 and #0fffh sacl teta_e .endif .if speed_scaling ******************************************************* Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 64 Application Report SPRA588 * Calculate speed and update reference speed variables ******************************************************* lacc speedstep ;are we in speed control loop ? (SPEEDSTEP ;times current control loop) sub #1 ; sacl speedstep ; bcnd nocalc,GT ;if we aren't, skip speed calculation *** Speed calculation from encoder pulses lt speedtmp ;multiply encoder pulses by Kspeed (8.8 ; format constant) ;to have the value of speed mpy #Kspeed ; pac ; rpt #7 ; sfr ; sacl n lacc #0 ;zero speedtmp for next calculation sacl speedtmp ; lacc #SPEEDSTEP ;restore speedstep to the value SPEEDSTEP sacl speedstep ;for next speed control loop .endif .if speed_regulator ***************************************************** * Speed regulator with integral component correction ***************************************************** lacc n_ref sub n sacl epispeed lacc xispeed,12 lt epispeed mpy Kpispeed apac sach upi,4 ;here start to saturate bit upi,0 bcnd upimagzeros,NTC ;If value +ve branch lacc iSqrefmin sub upi bcnd neg_sat,GT ;if upi<iqrmin then branch to saturate lacc upi ;value of upi is valid b limiters neg_sat lacc iSqrefmin ;set acc to -ve saturated value b limiters upimagzeros lacc sub bcnd lacc b pos_sat lacc limiters sacl sub sacl lt mpy pac lt mpy ;Value is positive iSqrefmax upi pos_sat,LT upi limiters ; ;if upi>iqrmax then branch to saturate ;value of upi valid iSqrefmax ;set acc to +ve saturated value iSqref upi elpi elpi Kcorspeed ;Store the acc as reference value epispeed Kispeed Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 65 Application Report SPRA588 apac add sach .endif xispeed,12 xispeed,4 .if speed_scaling **************************************************** * Encoder update **************************************************** nocalc ;branch here if we don't have to calculate ; the speed lacc speedtmp ;use the actual encoder increment to update ;the increments accumulator used to ; calculate the speed add encincr ; sacl speedtmp ; .endif Init .if current_scaling ********************************************* * Sampled current scaling * to nominal current 1000h <-> I_nominal ********************************************* ldp #ia lacc ia and #3ffh sub #440 ;then we have to subtract the offset (2.5V) to ; have positive and negative values of the ; sampled current sacl tmp spm 3 lt tmp mpy Kcurrent pac sfr sfr sacl ia ;sampled current ia, f 4.12 lacc ib and #3ffh sub #440 sacl tmp lt tmp mpy Kcurrent pac sfr sfr sacl ib add ia neg sacl ic ;ic = -(ib+ia) spm 0 .endif .if clarke ********************************************* * (a,b,c) -> (alfa,beta) axis transformation * iSalfa = ia * iSbeta = (2 * ib + ia) / sqrt(3) ********************************************* lacc ia sacl iSalfa Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 66 Application Report SPRA588 lacc add sacl lt mpy ib,1 ia tmp tmp SQRT3inv pac sach .endif iSbeta,4 ;iSbeta = (2 * ib + ia) / sqrt(3) ;SQRT3inv = (1 / sqrt(3)) = 093dh ;4.12 format = 0.577350269 .if sine_table ********************************************* * Sine and cosine wave calculation from * teta values using sine look-up table ********************************************* lacc teta_e ;teta range is [0;1000h] 4.12 ;so we have a pointer (in the ;to the sine look-up table in ;third nibble rpt #3 sfr and #0ffh ;now ACC contains the pointer sacl index add #sintab sacl tmp lar ar5,tmp nop ; prevent pipeline conflict nop mar *,ar5 lacl * nop sacl sin ;now we have sine value lacl index add and sacl add sacl lar lacc sacl .endif #040h #0ffh index #sintab tmp ar5,tmp * cos format = [0;360] range [0;0ffh]) the second and to access the table ;the same thing for cosine ... cos(teta) ;sin(teta+90°) ;90 degrees = 40h elements of the table ;we use the same pointer (we don't care) ;now we have cosine value .if park ********************************************* * d-axis and q-axis current calculation * (alfa,beta) -> (d,q) axis transformation * iSd = iSalfa * cos(teta_e) + iSbeta * sin(teta_e) * iSq =-iSalfa * sin(teta_e) + iSbeta * cos(teta_e) ********************************************* lacc #0 lt iSbeta ;TREG0=iSbeta mpy sin ;PREG=iSbeta*sin(teta_e) lta iSalfa ;ACC+=PREG ; TREG0=iSalfa mpy cos ;PREG=iSalfa*cos(teta_e) mpya sin ;ACC+=PREG ; PREG=iSalfa*sin(teta_e) sach iSd,4 lacc #0 ;ACC=0 lt iSbeta ;TREG0=ibeta mpys cos ;ACC-=(PREG=iSalfa*sin(teta_e)) Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 67 Application Report SPRA588 apac sach .endif ;ACC+=PREG iSq,4 .if isq_regulator ************************************************************** * q-axis current regulator with integral component correction * (iSq,iSqref)->(vSqref) ************************************************************** iq_reg: lacc iSqref sub iSq sacl epiq lacc xiq,12 lt epiq mpy Kpi apac sach upi,4 bit bcnd lacc sub bcnd lacc b neg_satq lacc b upi,0 upimagzeroq,NTC #Vmin upi neg_satq,GT ;if upi<Vmin branch to saturate upi ;value of upi is valid limiterq #Vmin limiterq upimagzeroq lacc #Vmax sub upi bcnd pos_satq,LT lacc upi b limiterq pos_satq lacc #Vmax limiterq sacl sub sacl lt mpy pac lt mpy apac add sach .endif vSqref upi elpi elpi Kcor ;set ACC to neg saturation ;Value was positive ; ;if upi>Vmax branch to saturate ;value of upi is valid ;set ACC to pos saturation ;Save ACC as reference value epiq Ki xiq,12 xiq,4 .if isd_regulator ************************************************************** * d-axis current regulator with integral component correction * (iSd,iSdref)->(vSdref) ************************************************************** lacc iSdref sub iSd sacl epid lacc xid,12 lt epid Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 68 Application Report SPRA588 mpy apac sach bit bcnd lacc sub bcnd lacc b neg_satd lacc b upimagzerod lacc sub bcnd lacc b pos_satd lacc limiterd sacl sub sacl lt mpy pac lt mpy apac add sach .endif Kpi upi,4 upi,0 upimagzerod,NTC #Vmin upi neg_satd,GT ;if upi<Vmin branch to saturate upi ;value of upi is valid limiterd #Vmin limiterd ;set ACC to neg saturation ;Value was positive #Vmax upi pos_satd,LT upi limiterd ; ;if upi>Vmax branch to saturate ;value of upi is valid #Vmax ;set ACC to pos saturation vSdref upi elpi elpi Kcor ;Save ACC as reference value epid Ki xid,12 xid,4 .if inv_park *********************************************** * alfa-axis and beta-axis voltages calculation * (d,q) -> (alfa,beta) axis transformation * vSbe_ref = vSqref * cos(teta_e) + vSdref * sin(teta_e) * vSal_ref =-vSqref * sin(teta_e) + vSdref * cos(teta_e) *********************************************** lacc #0 lt vSdref ;TREG0=vSdref mpy sin ;PREG=vSdref*sin(teta_e) lta vSqref ;ACC+=PREG ; TREG0=vSqref mpy cos ;PREG=vSqref*cos(teta_e) mpya sin ;ACC+=PREG ; PREG=vSqref*sin(teta_e) sach vSbe_ref,4 lacc #0 ;ACC=0 lt vSdref ;TREG0=vSdref mpys cos ;ACC-=(PREG=vSqref*sin(teta_e)) apac ;ACC+=PREG sach vSal_ref,4 .endif .if svpwm ********************************************** * Phase 1(=a) 2(=b) 3(=c) Voltage calculation * (alfa,beta) -> (a,b,c) axis transformation * modified exchanging alfa axis with beta axis * for a correct sector calculation in SVPWM * Va = vSbe_ref Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 69 Application Report SPRA588 * Vb = (-vSbe_ref + sqrt(3) * vSal_ref) / 2 * Vc = (-vSbe_ref - sqrt(3) * vSal_ref) / 2 *********************************************** lt vSal_ref ;TREG0=vSal_ref mpy SQRT32 ;PREG=vSal_ref*(SQRT(3)/2) pac ;ACC=PREG sub vSbe_ref,11 ;ACC-=vSbe_ref*2^11 sach Vb,4 pac ;ACC=PREG neg ;ACC=-ACC sub vSbe_ref,11 ;ACC-=vSbe_ref*2^11 sach Vc,4 lacl vSbe_ref ;ACC=vSbe_ref sacl Va ;Va=ACCL ************************************** * SPACE VECTOR Pulse Width Modulation * (see SVPWM references) ************************************** lt VDCinvT mpy SQRT32 pac sach tmp,4 lt tmp mpy vSbe_ref pac sach X,4 lacc X ;ACC = vSbe_ref*K1 sach accb sacl accb+1 ;ACCB = vSbe_ref*K1 sacl X,1 ;X=2*vSbe_ref*K1 lt VDCinvT splk #1800h,tmp mpy tmp ;implement mpy #01800h pac sach tmp,4 lt tmp mpy vSal_ref pac sach tmp,4 lacc tmp ;reload ACC with vSal_ref*K2 add accb+1 add accb,16 sacl Y ;Y = K1 * vSbe_ref + K2 * vSal_ref sub tmp,1 sacl Z ;Z = K1 * vSbe_ref - K2 * vSal_ref *** 60 degrees sector determination lacl #0 sacl sector lacc Va bcnd Va_neg,LEQ ;If Va<0 do not set bit 1 of sector lacc sector or #1 sacl sector ;implement opl #1,sector Va_neg lacc Vb bcnd Vb_neg,LEQ ;If Vb<0 do not set bit 2 of sector lacc sector or #2 sacl sector ;implement opl #2,sector Vb_neg lacc Vc bcnd Vc_neg,LEQ ;If Vc<0 do not set bit 3 of sector lacc sector or #4 sacl sector ;implement opl #4,sector Vc_neg Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 70 Application Report SPRA588 *** END 60 degrees sector determination *** T1 and T2 (= t1 and t2) calculation depending on the sector number lacl sector ;(see SPACE VECTOR Modulation references for ;details) sub #1 bcnd no1,NEQ lacc Z sacl t1 lacc Y sacl t2 b t1t2out no1 lacl sector sub #2 bcnd no2,NEQ lacc Y sacl t1 lacc X neg sacl t2 b t1t2out no2 lacl sector sub #3 bcnd no3,NEQ lacc Z neg sacl t1 lacc X sacl t2 b t1t2out no3 lacl sector sub #4 bcnd no4,NEQ lacc X neg sacl t1 lacc Z sacl t2 b t1t2out no4 lacl sector sub #5 bcnd no5,NEQ lacc X sacl t1 lacc Y neg sacl t2 b t1t2out no5 lacc Y neg sacl t1 lacc Z neg sacl t2 t1t2out lacc t1 ;t1 and t2 minumum values must be Tonmax sub #Tonmax bcnd t1_ok,GEQ ;if t1>Tonmax then t1_ok lacl #Tonmax sacl t1 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 71 Application Report SPRA588 t1_ok lacc t2 sub #Tonmax bcnd t2_ok,GEQ ;if t2>Tonmax then t2_ok lacl #Tonmax sacl t2 t2_ok *** END t1 and t2 calculation lacc add sacl sub bcnd t1 ;if t1+t2>2*Tonmax we have to saturate t1 and t2 t2 ; tmp ; #MAXDUTY ; nosaturation,LT,EQ *** t1 and t2 saturation lacc #MAXDUTY,15 ;divide MAXDUTY by (t1+t2) rpt #15 ; subc tmp ; sacl tmp ; lt tmp ;calculate saturate values of t1 and t2 mpy t1 ;t1 (saturated)=t1*(MAXDUTY/(t1+t2)) pac ; sach t1,1 ; mpy t2 ;t2 (saturated)=t2*(MAXDUTY/(t1+t2)) pac ; sach t2,1 ; *** END t1 and t2 saturation nosaturation *** taon,tbon and tcon calculation lacc #PWMPRD ;calculate the commutation instants taon, ;tbon and tcon sub t1 ;of the 3 PWM channels sub t2 ;taon=(PWMPRD-t1-t2)/2 sfr ; sacl taon ; add t1 ;tbon=taon+t1 sacl tbon ; add t2 ;tcon=tbon+t2 sacl tcon ; *** END taon,tbon and tcon calculation *** sector switching lacl sector sub #1 bcnd nosect1,NEQ bldd bldd bldd b nosect1 lacl sub bcnd bldd bldd bldd b nosect2 lacl sub bcnd tbon,#CMPR1 taon,#CMPR2 tcon,#CMPR3 dacout sector #2 nosect2,NEQ taon,#CMPR1 tcon,#CMPR2 tbon,#CMPR3 dacout ;depending on the sector number we have ;to switch the calculated taon, tbon and tcon ;to the correct PWM channel ;(see SPACE VECTOR Modulation references for ; details) ;sector 1 ;sector 2 ; ; sector #3 nosect3,NEQ Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 72 Application Report SPRA588 bldd taon,#CMPR1 ;sector 3 bldd tbon,#CMPR2 ; bldd tcon,#CMPR3 ; b dacout nosect3 lacl sector sub #4 bcnd nosect4,NEQ bldd tcon,#CMPR1 ;sector 4 bldd tbon,#CMPR2 ; bldd taon,#CMPR3 ; b dacout nosect4 lacl sector sub #5 bcnd nosect5,NEQ bldd tcon,#CMPR1 ;sector 5 bldd taon,#CMPR2 ; bldd tbon,#CMPR3 ; b dacout nosect5 bldd tbon,#CMPR1 ;sector 6 bldd tcon,#CMPR2 ; bldd taon,#CMPR3 ; *** END sector switching *** END * SPACE VECTOR Pulse Width Modulation .endif dacout **************************************************************** * DAC output of channels 'da1', 'da2', 'da3' and 'da4' * * Output on 12 bit Digital analog Converter * * 5V equivalent to FFFh * **************************************************************** ldp #sector lacc sector,7 ;scale sector by 2^7 to have good displaying sacl sectordisp ;only for display purposes *** DAC out channel 'da1' lacc #ia add da1 sacl daout lar ar5,daout lacc * sfr sfr add sacl out ;get the address of the first elements ;add the selected output variable offset ; 'da1' sent by the terminal ;now daout contains the address of the ; variable to send to DAC1 ;store it in AR5 ;indirect addressing, load the value to send out ;the following 3 instructions are required to ;adapt the numeric format to the DAC resolution ;on a 12 bit DAC, +/- 2000h = [0,5] Volt ;-2000h is 0 Volt #800h ;0 is 2.5 Volt. daouttmp ;to prepare the triggering of DAC1 buffer daouttmp,DAC0_VAL *** DAC out channel 'da2' lacc #ia add da2 sacl daout lar ar5,daout lacc * ;get the address of the first elements ;add the selected output variable offset ;'da1' sent by the terminal ;now daout contains the address of the ; variable to send to DAC1 ;store it in AR5 ;indirect addressing, load the value to send out ;the following 3 instructions are required to Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 73 Application Report SPRA588 ;adapt the numeric format to the DAC resolution ;we have 10 bit DAC, we want to have the ;number 2000h = 5 Volt sfr sfr add sacl out #800h ; daouttmp ;to prepare the triggering of DAC1 buffer daouttmp,DAC1_VAL *** DAC out channel 'da3' lacc #ia add da3 sacl daout lar ar5,daout lacc * sfr sfr add sacl out lar ar5,daout lacc * sfr OUT ;indirect addressing, load the value to send out ;the following 3 instructions are required to ;adapt the numeric format to the DAC resolution ;we have 10 bit DAC, we want to have the number ;2000h = 5 Volt #800h daouttmp ;to prepare the triggering of DAC1 buffer daouttmp,DAC2_VAL *** DAC out channel 'da4' lacc #ia add da4 ;sent by the terminal sacl daout sfr add sacl out *** END DAC ;get the address of the first elements ;add the selected output variable offset 'da1' ;sent by the terminal ;now daout contains the address of the variable ;to send to DAC1 ;store it in AR5 ;get the address of the first elements ;add the selected output variable offset 'da1' ;now daout contains the address of the ;variable to send to DAC1 ;store it in AR5 ;indirect addressing, load the value to send out ;the following 3 instructions are required ;to adapt the numeric format to the DAC resolution ;we have 10 bit DAC, we want to have the ;number 2000h = 5 Volt #800h daouttmp ;to prepare the triggering of DAC1 buffer daouttmp,DAC3_VAL out tmp,DAC_VAL ;start D to A convertion *** END: PWM enable b ContextRestoreReturn *END ControlRoutine .endif ContextRestoreReturn ************************************** * Context restore and Return ************************************** larp ar4 mar *+ lacl *+ ;Accu. restored for context restore add *+,16 lst #0,*+ Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 74 Application Report SPRA588 lst #1,*+ clrc INTM ret * END Context Restore and Return * *************** * Virtual Menu *************** menu .if virtual_menu ldp bit bcnd lacc and ldp sacl #DP_PF1 SCIRXST,BIT6 menu,ntc SCIRXBUF #0ffh #option option sub bcnd #031h notone,neq ;is there any character available ? ;if not repeat the cycle (polling) ;only 8 bits !!! ;if yes, get it and store it in option ;now in option we have the option number ;of the virtual menu ;is it option 1 ? ;if not branch to notone ***************************** * Option 1): Speed reference ***************************** navail11 ldp #DP_PF1 bit SCIRXST,BIT6 ;is there any character available (8 LSB)? bcnd navail11,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF and #0FFh ;take the 8 LSB ldp #serialtmp sacl serialtmp ;if yes, get it and store it in serialtmp navail12 ldp #DP_PF1 bit SCIRXST,BIT6 ;8 MSB available ? bcnd navail12,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF,8 ;load ACC the upper byte ldp #serialtmp add serialtmp ;add ACC with lower byte sacl n_ref ;store it b menu ;return to the main polling cycle *** END Option 1): speed reference notone lacc sub bcnd option #032h nottwo,neq ***************************** * Option 2): DAC update ***************************** navail21 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail21,ntc lacc SCIRXBUF and #0FFh ldp #da1 sacl da1 navail22 ldp #DP_PF1 ;is it option 2 ? ;if not branch to nottwo ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in da1 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 75 Application Report SPRA588 bit SCIRXST,BIT6 bcnd navail22,ntc lacc SCIRXBUF and #0FFh ldp #da1 sacl da2 navail23 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail23,ntc lacc SCIRXBUF and #0FFh ldp #da1 sacl da3 navail24 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail24,ntc lacc SCIRXBUF and #0FFh ldp #da1 sacl da4 b menu *** END Option 2): DAC update nottwo lacc sub bcnd option #033h notthree,neq ***************************** * Option 3): initphase ***************************** navail31 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail31,ntc lacc SCIRXBUF and #0FFh ldp #serialtmp sacl serialtmp navail32 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail32,ntc lacc SCIRXBUF,8 ldp #serialtmp add serialtmp sacl initphase b menu *** END Option 3): initphase notthree lacc sub bcnd option #034h notfour,neq ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in da2 ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in da3 ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in da4 ;return to the main polling cycle ;is it option 3 ? ;if not branch to notthree ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in serialtmp ;8 MSB available ? ;if not repeat the cycle (polling) ;load ACC the upper byte ;add ACC with lower byte ;store it ;return to the main polling cycle ;is it option 4 ? ;if not branch to notfour ***************************** * Option 4): vDCinvTc ***************************** navail41 ldp #DP_PF1 bit SCIRXST,BIT6 ;is there any character available (8 LSB)? bcnd navail41,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 76 Application Report SPRA588 and #0FFh ldp #serialtmp sacl serialtmp navail42 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail42,ntc lacc SCIRXBUF,8 ldp #serialtmp add serialtmp sacl VDCinvT b menu *** END Option 4): vDCinvTc notfour lacc sub bcnd option #035h notfive,neq ***************************** * Option 5): Kpi, Ki, Kcor ***************************** navail51 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail51,ntc lacc SCIRXBUF and #0FFh ldp #serialtmp sacl serialtmp navail52 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail52,ntc lacc SCIRXBUF,8 ldp #serialtmp add serialtmp sacl Kpi navail53 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail53,ntc lacc SCIRXBUF and #0FFh ldp #serialtmp sacl serialtmp navail54 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail54,ntc lacc SCIRXBUF,8 ldp #serialtmp add serialtmp sacl Ki navail55 ldp #DP_PF1 bit SCIRXST,BIT6 bcnd navail55,ntc lacc SCIRXBUF and #0FFh ldp #serialtmp sacl serialtmp navail56 ldp #DP_PF1 bit SCIRXST,BIT6 ;take the 8 LSB ;if yes, get it and store it in serialtmp ;8 MSB available ? ;if not repeat the cycle (polling) ;load ACC the upper byte ;add ACC with lower byte ;store it ;return to the main polling cycle ;is it option 5 ? ;if not branch to notfive ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in serialtmp ;8 MSB available ? ;if not repeat the cycle (polling) ;load ACC the upper byte ;add ACC with lower byte ;store it ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in serialtmp ;8 MSB available ? ;if not repeat the cycle (polling) ;load ACC the upper byte ;add ACC with lower byte ;store it ;is there any character available (8 LSB)? ;if not repeat the cycle (polling) ;take the 8 LSB ;if yes, get it and store it in serialtmp ;8 MSB available ? Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 77 Application Report SPRA588 bcnd navail56,ntc lacc SCIRXBUF,8 ldp #serialtmp add serialtmp sacl Kcor b menu *** END Option notfive lacc sub bcnd option #036h notsix,neq ;if not repeat the cycle (polling) ;load ACC the upper byte ;add ACC with lower byte ;store it ;return to the main polling cycle ;is it option 6 ? ;if not branch to notsix ***************************** * Option 6): Kpispeed , Kispeed , Kcorspeed ***************************** navail61 ldp #DP_PF1 bit SCIRXST,BIT6 ;is there any character available (8 LSB)? bcnd navail61,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF and #0FFh ;take the 8 LSB ldp #serialtmp sacl serialtmp ;if yes, get it and store it in serialtmp navail62 ldp #DP_PF1 bit SCIRXST,BIT6 ;8 MSB available ? bcnd navail62,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF,8 ;load ACC the upper byte ldp #serialtmp add serialtmp ;add ACC with lower byte sacl Kpispeed ;store it navail63 ldp #DP_PF1 bit SCIRXST,BIT6 ;is there any character available (8 LSB)? bcnd navail63,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF and #0FFh ;take the 8 LSB ldp #serialtmp sacl serialtmp ;if yes, get it and store it in serialtmp navail64 ldp #DP_PF1 bit SCIRXST,BIT6 ;8 MSB available ? bcnd navail64,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF,8 ;load ACC the upper byte ldp #serialtmp add serialtmp ;add ACC with lower byte sacl Kispeed ;store it navail65 ldp #DP_PF1 bit SCIRXST,BIT6 ;is there any character available (8 LSB)? bcnd navail65,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF and #0FFh ;take the 8 LSB ldp #serialtmp sacl serialtmp ;if yes, get it and store it in serialtmp navail66 ldp #DP_PF1 bit SCIRXST,BIT6 ;8 MSB available ? bcnd navail66,ntc ;if not repeat the cycle (polling) lacc SCIRXBUF,8 ;load ACC the upper byte ldp #serialtmp add serialtmp ;add ACC with lower byte sacl Kcorspeed ;store it b menu ;return to the main polling cycle Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 78 Application Report SPRA588 *** END Option notsix b menu .else ldp splk #n_ref #1000h,n_ref lacc stall_timer1 sub sacl bcnd #1 stall_timer1 norun,GT lacc sub sacl bcnd stall_timer2 #1 stall_timer2 norun,GT splk splk splk #01000h,initphase #0,stall_timer1 #0,stall_timer2 ;cascaded timers to ensure correct stall ;at start ;when no Graphic User's Interface is available b menu norun splk #0,initphase b menu .endif Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 79 Application Report SPRA588 Appendix B. Qbasic Graphic User’s Interface REM File name : FOC_PMSM.BAS OPEN "COM1: 9600,N,8,1,CD0,CS0,DS0,OP0,RS,TB1,RB1" FOR OUTPUT AS #1 PRINT #1, "1"; CHR$(0); CHR$(0); : REM speed reference initialization to 0 PRINT #1, "2"; CHR$(23); CHR$(25); CHR$(41); CHR$(3); : REM dac initialization PRINT #1, "3"; CHR$(0); CHR$(0); : REM initialization phase to 0 est = 0 speedref = 0 init = 0 VDC = 311 da1 = 33: da2 = 32 da3 = 24: da4 = 25 Ki = .03 Kpi = .6 Kcor = .05 Kispeed = .03 Kpispeed = 6.5 Kcorspeed = .0046 initphase$(0) = "Init" initphase$(1) = "Run" Tc = 896: REM PWM period in us speedpu = 3000: REM base speed ibase = 2: REM base current Vbase = 120 DIM daout$(200) daout$(0) = "ia" daout$(1) = "ib" daout$(2) = "ic" daout$(3) = "Ua" daout$(4) = "Ub" daout$(5) = "Uc" daout$(6) = "seno1" daout$(7) = "t1" daout$(8) = "t2" daout$(9) = "coseno" daout$(10) = "Va" daout$(11) = "Vb" daout$(12) = "Vc" daout$(13) = "VDC" daout$(14) = "taon" daout$(15) = "tbon" daout$(16) = "tcon" daout$(17) = "teta" daout$(18) = "ialfa" daout$(19) = "ibeta" daout$(20) = "Valfar" daout$(21) = "Vbetar" daout$(22) = "idr" daout$(23) = "iqr" daout$(24) = "idS" daout$(25) = "iqS" daout$(26) = "Vdr" daout$(27) = "Vqr" daout$(28) = "epiq" daout$(29) = "epid" daout$(30) = "xiq" Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 80 Application Report SPRA588 daout$(31) = "xid" daout$(32) = "n" daout$(33) = "n_ref" daout$(34) = "epispeed" daout$(35) = "xispeed" daout$(36) = "X" daout$(37) = "Y" daout$(38) = "Z" daout$(39) = "sector" daout$(40) = "initphase" REM daout$(41) = "Vr" REM daout$(42) = "idrref" daout$(43) = "" daout$(44) = "" daout$(45) = "" nDA = 10 1 CLS FOR i = 0 TO nDA COLOR 11 LOCATE (12 + i), 2: PRINT "("; : PRINT USING "##"; i; : PRINT ") "; daout$(i) LOCATE (12 + i), 22: PRINT "("; : PRINT USING "##"; i + nDA + 1; : PRINT ") "; daout$(i + nDA + 1) LOCATE (12 + i), 42: PRINT "("; : PRINT USING "##"; i + 2 * nDA + 2; : PRINT ") "; daout$(i + 2 * nDA + 2) LOCATE (12 + i), 62: PRINT "("; : PRINT USING "##"; i + 3 * nDA + 3; : PRINT ") "; daout$(i + 3 * nDA + 3) NEXT i LOCATE 1, 15 COLOR 12: PRINT " Digital Control of a Permanent Magnet Motor" PRINT COLOR 10: PRINT "<1>"; : COLOR 2: PRINT " Speed_reference ("; speedref; "rpm )" COLOR 10: PRINT "<2>"; : COLOR 2: PRINT " DAC_Outputs DAC1: ("; daout$(da1); ")" LOCATE 4, 35: PRINT "DAC2: ("; daout$(da2); ")" PRINT " DAC3: ("; daout$(da3); ")" LOCATE 5, 35: PRINT "DAC4: ("; daout$(da4); ")" COLOR 10: PRINT "<3>"; : COLOR 2: PRINT " Init_phase (0=Init) ("; initphase$(init); ")" COLOR 10: PRINT "<4>"; : COLOR 2: PRINT " Vbase ("; Vbase; "Volts )" COLOR 10: LOCATE 3, 50: PRINT " <5>"; : COLOR 2: PRINT " Kpi ("; Kpi; "pu)" COLOR 10: LOCATE 4, 50: PRINT " "; : COLOR 2: PRINT " Ki ("; Ki; "pu)" COLOR 10: LOCATE 5, 50: PRINT " "; : COLOR 2: PRINT " Kcor ("; Kcor; "pu)" COLOR 10: LOCATE 6, 50: PRINT " <6>"; : COLOR 2: PRINT " Kpispeed ("; Kpispeed; "pu)" COLOR 10: LOCATE 7, 50: PRINT " "; : COLOR 2: PRINT " Kispeed ("; Kispeed; "pu)" COLOR 10: LOCATE 8, 50: PRINT " "; : COLOR 2: PRINT " Kcorspeed ("; Kcorspeed; "pu)" COLOR 10: LOCATE 10, 14: PRINT "Choice : "; DO a$ = INKEY$ LOOP UNTIL ((a$ <= "6") AND (a$ >= "1")) OR (a$ = "r") OR (a$ = "R") SELECT CASE a$ CASE "1" REM 4.12 format PRINT a$; ") "; PRINT "Speed_Reference ("; speedref; "rpm ) : "; INPUT speedref$ IF speedref$ = "" THEN 1 speedrpu = VAL(speedref$) / speedpu IF (speedrpu >= 7.999755859#) THEN speedrpu = 7.999755859# IF (speedrpu <= -8) THEN speedrpu = -8 speedrefpu = CLNG(speedrpu * 4096) IF (speedref < 0) THEN speedrefpu = 65536 + speedrefpu Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 81 Application Report SPRA588 PRINT #1, "1"; CHR$(speedrefpu AND 255); CHR$((speedrefpu AND 65280) / 256) speedref = speedrpu * speedpu GOTO 1 CASE "2" REM standard decimal format PRINT a$; ") "; PRINT "DAC1, DAC2, DAC3 or DAC4 ? "; 2 dach$ = INKEY$ IF dach$ = "" THEN 2 IF dach$ = CHR$(13) THEN 1 IF dach$ = "1" THEN PRINT "DAC1 Output ("; da1; ") : "; INPUT da$ IF da$ = "" THEN 1 da1 = VAL(da$) END IF IF dach$ = "2" THEN PRINT "DAC2 Output ("; da2; ") : "; INPUT da$ IF da$ = "" THEN 1 da2 = VAL(da$) END IF IF dach$ = "3" THEN PRINT "DAC3 Output ("; da3; ") : "; INPUT da$ IF da$ = "" THEN 1 da3 = VAL(da$) END IF IF dach$ = "4" THEN PRINT "DAC4 Output ("; da4; ") : "; INPUT da$ IF da$ = "" THEN 1 da4 = VAL(da$) END IF PRINT #1, "2"; CHR$(da1 AND 255); CHR$(da2 AND 255); CHR$(da3 AND 255); CHR$(da4 AND 255) GOTO 1 CASE "3" REM 8.8 format est = 0 IF init = 1 THEN init = 0 ELSE init = 1 IF (init >= 255.9960938#) THEN init = 255.9960938# IF (init < 0) THEN init = 0 init88 = CLNG(init * 256) PRINT #1, "3"; CHR$(init88 AND 255); CHR$((init88 AND 65280) / 256) GOTO 1 CASE "4" REM 4.12 format PRINT a$; ") "; PRINT "Vbase ("; Vbase; "Volts ) : "; INPUT Vbase$ IF Vbase$ = "" THEN 1 IF (Vbase <= 0) THEN 1 VDCpu = VDC / VAL(Vbase$) IF (VDCpu >= 7.999755859#) THEN VDCpu = 7.999755859# IF (VDCpu <= -8) THEN VDCpu = -8 VDCinvTc = Tc / VDCpu PRINT #1, "4"; CHR$(VDCinvTc AND 255); CHR$((VDCinvTc AND 65280) / 256) Vbase = VDC / VDCpu GOTO 1 CASE "5" REM 4.12 format PRINT a$; ") "; Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 82 Application Report SPRA588 PRINT "Kpi ("; Kpi; " ) : "; INPUT Kpi$ IF Kpi$ = "" THEN 51 Kpi = VAL(Kpi$) IF (Kpi >= 1) THEN Kpi = 1 IF (Kpi <= -1) THEN Kpi = -1 51 PRINT " INPUT Ki$ IF Ki$ = "" THEN 52 Ki = VAL(Ki$) IF (Ki >= 1) THEN Ki = 1 IF (Ki <= -1) THEN Ki = -1 Ki ("; Ki; " ) : "; 52 Kpipu = 4096 * Kpi Kipu = 4096 * Ki Kcor = (Ki / Kpi) Kcorpu = 4096 * Kcor PRINT #1, "5"; CHR$(Kpipu AND 255); CHR$((Kpipu AND 65280) / 256); CHR$(Kipu AND 255); CHR$((Kipu AND 65280) / 256); CHR$(Kcorpu AND 255); CHR$((Kcorpu AND 65280) / 256) GOTO 1 CASE "6" REM 4.12 format PRINT a$; ") "; PRINT "Kpispeed ("; Kpispeed; " ) : "; INPUT Kpispeed$ IF Kpispeed$ = "" THEN 61 Kpispeed = VAL(Kpispeed$) IF (Kpispeed >= 7.9) THEN Kpispeed = 7.9 IF (Kpispeed <= 0) THEN Kpispeed = 0 61 PRINT " Kispeed ("; Kispeed; " ) : "; INPUT Kispeed$ IF Kispeed$ = "" THEN 62 Kispeed = VAL(Kispeed$) IF (Kispeed >= 1) THEN Kispeed = 1 IF (Kispeed <= 0) THEN Kispeed = 0 62 Kpispeedpu = 4096 * Kpispeed Kispeedpu = 4096 * Kispeed Kcorspeed = (Kispeed / Kpispeed) Kcorspeedpu = 4096 * Kcorspeed REM Send "Option" - "LSB" - "MSB" PRINT #1, "6"; CHR$(Kpispeedpu AND 255); CHR$((Kpispeedpu AND 65280) / 256); CHR$(Kispeedpu AND 255); CHR$((Kispeedpu AND 65280) / 256); CHR$(Kcorspeedpu AND 255); CHR$((Kcorspeedpu AND 65280) / 256) GOTO 1 CASE ELSE PRINT #1, "1"; CHR$(speedrefpu AND 255); CHR$((speedrefpu AND 65280) / 256) PRINT #1, "2"; CHR$(da1 AND 255); CHR$(da2 AND 255); CHR$(da3 AND 255); CHR$(da4 AND 255) REM PRINT #1, "3"; CHR$(init88 AND 255); CHR$((init88 AND 65280) / 256) REM PRINT #1, "4"; CHR$(VDCinvTc AND 255); CHR$((VDCinvTc AND 65280) / 256) REM PRINT #1, "5"; CHR$(Kpipu AND 255); CHR$((Kpipu AND 65280) / 256); CHR$(Kipu AND 255); CHR$((Kipu AND 65280) / 256); CHR$(Kcorpu AND 255); CHR$((Kcorpu AND 65280) / 256) REM PRINT #1, "6"; CHR$(Kpispeedpu AND 255); CHR$((Kpispeedpu AND 65280) / 256); CHR$(Kispeedpu AND 255); CHR$((Kispeedpu AND 65280) / 256); CHR$(Kcorspeedpu AND 255); CHR$((Kcorspeedpu AND 65280) / 256) GOTO 1 END SELECT CLOSE #1 Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 83 Application Report SPRA588 Appendix C. Linker Command File foc_pmsm.obj -m foc_pmsm.map -o foc_pmsm.out MEMORY { PAGE 0: FLASH_VEC FLASH PAGE 1: REGS BLK_B22 BLK_B0 BLK_B1 EXT_DATA : origin = : origin = : : : : : origin origin origin origin origin = = = = = 0h, length = 040h, length = 0h, 60h, 200h, 300h, 8000h, length length length length length = = = = = 40h 00FC0h 60h 20h 100h 100h 1000h } /*---------------------------------------------------------------------*/ /* SECTIONS ALLOCATION */ /*---------------------------------------------------------------------*/ SECTIONS { vectors : { } > FLASH_VEC PAGE 0 /* INTERRUPT VECTOR TABLE */ .text : { } > FLASH PAGE 0 /* CODE */ .stack : { } > BLK_B22 PAGE 1 /* Data storage on DP 0 */ .dacval : { } > BLK_B22 PAGE 1 .data : { } > BLK_B0 PAGE 1 .bss : { } > BLK_B0 PAGE 1 /* GLOBAL VARS, STACK, HEAP*/ table : { } > BLK_B1 PAGE 1 } Implementation of a Speed Field Oriented Control of 3-phase PMSM Motor using TMS320F240 84 TI Contact Numbers INTERNET TI Semiconductor Home Page www.ti.com/sc TI Distributors www.ti.com/sc/docs/distmenu.htm PRODUCT INFORMATION CENTERS Americas Phone +1(972) 644-5580 Fax +1(972) 480-7800 Email [email protected] Europe, Middle East, and Africa Phone Deutsch +49-(0) 8161 80 3311 English +44-(0) 1604 66 3399 Español +34-(0) 90 23 54 0 28 Francais +33-(0) 1-30 70 11 64 Italiano +33-(0) 1-30 70 11 67 Fax +44-(0) 1604 66 33 34 Email [email protected] Japan Phone International +81-3-3344-5311 Domestic 0120-81-0026 Fax International +81-3-3344-5317 Domestic 0120-81-0036 Email [email protected] Asia Phone International +886-2-23786800 Domestic Australia 1-800-881-011 TI Number -800-800-1450 China 10810 TI Number -800-800-1450 Hong Kong 800-96-1111 TI Number -800-800-1450 India 000-117 TI Number -800-800-1450 Indonesia 001-801-10 TI Number -800-800-1450 Korea 080-551-2804 Malaysia 1-800-800-011 TI Number -800-800-1450 New Zealand 000-911 TI Number -800-800-1450 Philippines 105-11 TI Number -800-800-1450 Singapore 800-0111-111 TI Number -800-800-1450 Taiwan 080-006800 Thailand 0019-991-1111 TI Number -800-800-1450 Fax 886-2-2378-6808 Email [email protected] TI is a trademark of Texas Instruments Incorporated. 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