BLDC Estimator UG0608 User Guide Table of Contents Introduction ....................................................................................................................3 Hardware Implementation .............................................................................................4 BLDC Estimator Implementation ................................................................................................................... 4 Inputs and Outputs ........................................................................................................................................ 5 Configuration Parameters .............................................................................................................................. 6 Timing Diagram ............................................................................................................................................. 6 Resource Utilization ....................................................................................................................................... 6 List of Changes ..............................................................................................................7 Product Support.............................................................................................................8 Customer Service .......................................................................................................................................... 8 Customer Technical Support Center ............................................................................................................. 8 Technical Support .......................................................................................................................................... 8 Website .......................................................................................................................................................... 8 Contacting the Customer Technical Support Center ..................................................................................... 8 ITAR Technical Support ................................................................................................................................ 9 2 UG0608: BLDC Estimator User Guide Introduction The BLDC (Position and Speed) Estimator computes the rotor position based on motor parameters, voltages, and currents. The algorithm is based on back-emf estimation and filtering. The motor parameters Rs, Ls, and sampling time Ts are used to build motor model. The voltages that are fed to the actual motor are fed to the motor model along with motor currents and are used to compute back-emf. A PLL structure is used to find the angle of filtered back emf which is aligned to rotor electrical position. Position Vαβ Iαβ Rs Ls/Ts Eα Back EMF computation Eβ Filter Ref Phase error computation Act PI controller Speed Filter Filtered Speed Filter Tuning parameters Figure 1 · Block Diagram of BLDC Estimator The motor can accelerate or decelerate rapidly, in this case the rate of change of rotor position has to be dynamically and accurately tracked by the PLL. This is achieved by proper tuning of the PI controller that is part of the PLL. UG0608: BLDC Estimator User Guide 3 Hardware Implementation This section describes the implementation details of the BLDC Estimator. BLDC Estimator Implementation The system-level block diagram of the BLDC Estimator is as shown in Figure 2. reset_i sys_clk_i angle_pi_en_i start_i v_alpha_i done_o v_beta_i theta_o i_alpha_i ealpha_o i_beta_i ls_by_Ts_pu_i rs_pu_i ealpha_filter_factor_i ebeta_filter_factor_i BLDC Estimator ebeta_o ealpha_filtered_o ebeta_filtered_o pll_pi_out_o speed_filtered_o pll_theta_factor_i angle_pi_ki_i angle_pi_kp_i omega_filter_factor_i Figure 2 · System-Level Block Diagram of BLDC Estimator 4 UG0608: BLDC Estimator User Guide Hardware Implementation Inputs and Outputs Table 1 shows the input and output ports of the BLDC Estimator. Table 1 · Input and Output Ports of the BLDC Estimator Signal Name Type Description reset_i Input Active low synchronous reset signal sys_clk_i Input System clock start_i Input Start signal to start module computation - should be high for one system clock cycle angle_pi_en_i Input Enable signal for PLL PI controller v_alpha_i Input Alpha axis voltage input for angle estimation v_beta_i Input Beta axis voltage input for angle estimation i_alpha_i Input Alpha axis current input for angle estimation i_beta_i Input Beta axis current input for angle estimation Ls_by_Ts_pu_i Input Motor Inductance L (in per unit) / sampling time Rs_pu_i Input Motor Resistance R (in per unit) ealpha_filter_factor_i Input Represents the Ealpha filter time constant – input as an exponent of 2 ebeta_filter_factor_i Input Represents the Ebeta filter time constant – input as an exponent of 2 pll_theta_factor_i Input Theta factor value angle_pi_kp_i Input Proportional constant for Angle PI angle_pi_ki_i Input Integral constant for Angle PI omega_filter_factor_i Input Represents the speed filter time constant – input as an exponent of 2 2^(omega_filter_factor_i) * sampling time done_o Output Indicates completion of speed computation. High for one clock cycle. theta_o Output Estimated angle (theta) output ealpha_o Output Back-emf on alpha axis ebeta_o Output Back-emf on beta axis ealpha_filtered_o Output Filtered back-emf on alpha axis ebeta_filtered_o Output Filtered back-emf on beta axis pll_pi_out_o Output Speed output from PLL speed_filtered_o Output Filtered speed output UG0608: BLDC Estimator User Guide 5 Configuration Parameters Configuration Parameters Table 2 shows the configuration parameters used in the hardware implementation of the BLDC Estimator. These parameters are generic and can be varied based on the application requirement. Table 2 · Configuration Parameters of the BLDC Estimator Name Description g_STD_IO_WIDTH Defines the width of the input and output signals. g_NO_MCYCLE_PATH Defines the number of clock delays required before asserting the multiplier done signal. Timing Diagram Figure 3 shows the timing diagram of the BLDC Estimator. CLOCK FLUX_ESIMATOR_ START FLUX_ESIMATOR_ DONE EALPHA_FILTER _START EALPHA_FILTER_ DONE EBETA_FILTER _START EBETA_FILTER_ DONE PLL_THETA _START PLL_THETA_ DONE OMEGA_PI_ START OMEGA_PI_ DONE OMEGA_FILTER_ START OMEGA_FILTER_ DONE Figure 3 · Timing Diagram of the BLDC Estimator Resource Utilization ® BLDC Estimator is implemented on the SmartFusion 2 system-on-chip (SoC) field programmable gate array (FPGA) ® and IGLOO 2 devices. Table 3 shows the resource utilization report after synthesis with g_STD_IO_WIDTH value equal to 18. Table 3 · Resource Utilization of the BLDC Estimator Cell Usage 6 Description Sequential Elements 1077 Combinational Logic 1473 MACC 3 RAM1kx18 0 RAM64x18 0 UG0608: BLDC Estimator User Guide List of Changes The following table shows important changes made in this document for each revision. Date and Revision Revision 2 Change Page Updated SAR (71202). NA Initial release. NA (October 2015) Revision 1 (February 2015) UG0608: BLDC Estimator User Guide 7 Product Support Microsemi SoC Products Group backs its products with various support services, including Customer Service, Customer Technical Support Center, a website, electronic mail, and worldwide sales offices. This appendix contains information about contacting Microsemi SoC Products Group and using these support services. Customer Service Contact Customer Service for non-technical product support, such as product pricing, product upgrades, update information, order status, and authorization. From North America, call 800.262.1060 From the rest of the world, call 650.318.4460 Fax, from anywhere in the world 650. 318.8044 Customer Technical Support Center Microsemi SoC Products Group staffs its Customer Technical Support Center with highly skilled engineers who can help answer your hardware, software, and design questions about Microsemi SoC Products. The Customer Technical Support Center spends a great deal of time creating application notes, answers to common design cycle questions, documentation of known issues and various FAQs. So, before you contact us, please visit our online resources. It is very likely we have already answered your questions. Technical Support For Microsemi SoC Products Support, visit http://www.microsemi.com/products/fpga-soc/design-support/fpga-socsupport. Website You can browse a variety of technical and non-technical information on the Microsemi SoC Products Group home page, at http://www.microsemi.com/products/fpga-soc/fpga-and-soc. Contacting the Customer Technical Support Center Highly skilled engineers staff the Technical Support Center. The Technical Support Center can be contacted by email or through the Microsemi SoC Products Group website. Email You can communicate your technical questions to our email address and receive answers back by email, fax, or phone. Also, if you have design problems, you can email your design files to receive assistance. We constantly monitor the email account throughout the day. When sending your request to us, please be sure to include your full name, company name, and your contact information for efficient processing of your request. The technical support email address is [email protected]. My Cases Microsemi SoC Products Group customers may submit and track technical cases online by going to My Cases. UG0608: BLDC Estimator User Guide 8 Product Support Outside the U.S. Customers needing assistance outside the US time zones can either contact technical support via email ([email protected]) or contact a local sales office. Visit About Us for sales office listings and corporate contacts. ITAR Technical Support For technical support on RH and RT FPGAs that are regulated by International Traffic in Arms Regulations (ITAR), contact us via [email protected]. Alternatively, within My Cases, select Yes in the ITAR drop-down list. For a complete list of ITAR-regulated Microsemi FPGAs, visit the ITAR web page. UG0608: BLDC Estimator User Guide 9 Microsemi Corporation (Nasdaq: MSCC) offers a comprehensive portfolio of semiconductor and system solutions for communications, defense & security, aerospace and industrial markets. Products include high-performance and radiation-hardened analog mixed-signal integrated circuits, FPGAs, SoCs and ASICs; power management products; timing and synchronization devices and precise time solutions, setting the world’s standard for time; voice processing devices; RF solutions; discrete components; security technologies and scalable anti-tamper products; Ethernet solutions; Power-over-Ethernet ICs and midspans; as well as custom design capabilities and services. Microsemi is headquartered in Aliso Viejo, Calif., and has approximately 3,600 employees globally. Learn more at www.microsemi.com. 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