Fact Sheet Dual Sensorless PMSM FOC with PFC Reference Design Target Applications Overview • Refrigeration systems Advancements in motor control require new techniques for increased efficiency and increased integration to reduce costs. This reference design provides a three-in-one solution with advanced motor algorithms, running both a compressor motor and a fan motor with power factor correction (PFC)—all in a single MCU. • Air conditioning Dual SensorlessPMSM PMSM FOC with Reference Design Dual Sensorless FOC With PFCPFC Reference Design M2 PWM Vin Motor 2 DC bus voltage M2 currents Ambient, hot-side, cold-side temperatures Condenser Evaporator M1 PWM Input voltage PFC current Warm Air PFC PWM Compressor Touch Graphic LCD DC bus voltage UART 16-bit ADC PWMA SM 3 PWMA SM 0, 1, 2 PWMB SM 0, 1, 2 12-bit ADC Driver Driver Driver Driver Driver Driver Input Voltage Tx Communication State Machine Compressor speed PFC Current PFC State Machine Status, recorder Application State Machine Freescale Technology PFC switch, voltage command PWM PWM PWM Motor 1 State Machine Capillary Motor 2 State Machine M1 phase currents PFC status M1 switch, speed command M1 status M2 switch, speed command M2 status Water Refrigerant RS232-isolated Switch Capillary Tube M1 currents Motor 1 Rx Moist Air Fan M2 phase currents DC bus voltage Features Dual Sensorless Motor Control • Vector control of sensorless PMSM Freescale’s digital signal controllers Freescale Embedded Software and Motor Control Libraries (specifically MC56F84789) provide enough Most dedicated algorithms such as timing channels and ADCs to operate • Rotation in one direction (possible for both) transformations, PI controllers and space two 3-phase motors simultaneously while vector modulation are implemented using • Start from any motor position with rotor executing a back EMF algorithm that is Freescale Embedded Software Libraries tailored to both the compressor and the fan, (FSLESL). These libraries provide a jump- enabling sensorless control. This removes the start for designers implementing their control need for a position sensor and an additional architecture. • Vector control with speed-closed-loop alignment • Four-quadrant operation • Sensorless position and speed estimation • Three-shunt current sensing MCU and reduces the overall cost of the solution. Touch Graphic LCD The reference design has added an HMI • Wide speed range Power Factor Correction (PFC) • Interleaved PFC control Typically PFC is a function handled by an with full capacitive touch and an integrated additional external IC, however this reference LCD controller, providing the framework design has integrated the function into the for the consumer’s next-generation, cost- digital signal controller due to its outstanding effective, high-efficiency, low-noise, variable- performance capabilities. The PFC profiles the power advanced refrigeration system. • Serial inter-board communication • Touch graphic LCD control interface • Application monitoring speed, voltage, current, temperature and three-phase current scope interface using Freescale’s Kinetis K70 MCU consumed current to be sinusoidal in phase with the power line voltage. Field-Oriented Control (FOC) Software Tools FreeMASTER is a free debugging tool used to evaluate variables while the motors Vector control (also called field-oriented operate and also supports the Motor Control control) is an elegant method to control a Application Tuning (MCAT) tool that enables PMSM, where field-oriented theory is used the control parameters of the application to to control space vectors of magnetic flux, be set up easily. Using this tool, the user can current and voltage. It is possible to set up the modify the parameters of control loops which system coordinates to decompose the vectors change the properties of the control process. into a magnetic field-generating part and a The control reaction for these parameter torque-generating part. The structure of the changes can be triggered and visualized using motor controller is then almost the same as a the FreeMASTER recorder functionality. separately excited DC motor, which simplifies the control of a PMSM. This technique, used with a properly designed motor, provides improved efficiency and quieter operation than traditional implementations. Permanent Magnet Synchronous Motors (PMSM) PMSMs are desirable due to their higher efficiency and better power density compared to traditional motors. There is no excitation needed because the motor magnetic flux is generated by permanent magnets placed on the rotor. For current information about Freescale motor control products and documentation, please visit freescale.com/motorcontrol Freescale, the Freescale logo and Kinetis are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. All other product or service names are the property of their respective owners. © 2013 Freescale Semiconductor, Inc. Document Number: DSPMSMFOCPFCFS REV 0