Freescale Semiconductor, Inc | Motorola M68HC08 instruction

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

during several commutations, while producing the required torque. Until the back-EMF feedback is locked, the commutation process (explained in Running) assures that commutations are done in advance, so that successive back-EMF zero crossing events are not missed.

After several successive back-EMF zero crossings:

•Exact commutation time can be calculated

•Commutation process is adjusted

•Control flow continues to the Running state

The BLDC motor is then running with regular feedback and the speed controller can be used to control the motor speed by changing the PWM duty cycle value.

Designer Reference Manual		DRM028 — Rev 0

46	BLDC Motor Control	MOTOROLA
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Motorola M68HC08 manual Freescale Semiconductor, Inc

Contents

M68HC08 Freescale Semiconductor, Inc For More Information On This Product Sensorless Bldc Motor Control Using MC68HC908MR32 Designer Reference Manual Rev Revision history List of Sections List of Sections Table of Contents Table of Contents List of Figures Title List of Figures List of Tables List of Tables Introduction ContentsBenefits of the Solution Application Functionality Introduction System Description System Concept System Description System Specification Software parameter tuning to a customer motor Software SpecificationSoftware written in C language specifications are listed Software Specifications Hardware and Drive Specifications High-Voltage Hardware Set Specification High Voltage Hardware Set Specifications Motor -Brake Set Low Voltage Evaluation Hardware Set Specifications Low-Voltage Evaluation Hardware Set SpecificationLow-Voltage Hardware Set Specification Low Voltage Hardware Set Specifications Brushless DC Motor Control Theory Bldc Motor ControlBldc Motor Targeted by This Application Semiconductor, Inc Bldc Motor Control Brushless DC Motor Control Theory Bldc Motor Back EMF and Magnetic Flux 2 3-Phase Bldc Power Stage Why Sensorless Control? Power Stage Motor Topology Stator Winding Equations Indirect Back EMF Sensing Same expressions can also be found for phase a and B Phase Voltage Waveform Effect of Mutual Inductance Mutual Inductance Effect Effect of Mutual Phase Capacitance Detail of Mutual Inductance Effect Mutual Capacitance Model 10. Distributed Back-EMF by Unbalanced Capacity Coupling 11. Balanced Capacity Coupling Back-EMF Sensing Circuit Inc Sensorless Commutation Control Used Control TechniqueAlignment Starting Back-EMF Acquisition Running 14. Commutation Control Stages Alignment 15. Alignment Running Freescale Semiconductor, Inc Running Commutation Time Calculation Commutation time calculation is shown in Figure Service of received back-EMF zero crossing 17. Bldc Commutation Time with Zero Crossing Sensing Where Starting Back-EMF Acquisition Freescale Semiconductor, Inc 18. Vectors of Magnetic Fields 19. Back-EMF at Start Up Running Commutation Time Calculation, but the following Starting Commutation Time CalculationComputation coefficients are different Speed Control Application ControlPC Master Software Communication with PC Master Software Specifications PC Master Software Communication Commands PC Master Software API Variables Name Type Representing Description Range MotorStatusDef, FailureDef BIT6 Reserved BIT2 Reserved PerSpeedMAXRange and zero crossing period PerZCrosFltT2 SpeedRangeMaxRPM*PerSpeedMAXRange/PerZCrosFltT2 Freescale Semiconductor, Inc MC68HC908MR32 Control Board System Configuration and DocumentationHardware Design For High-Voltage Hardware Set cofiguration Low-Voltage Hardware Set configuration For Low-Voltage Evaluation Motor Hardware Set configurationEVM Motor Board Phase Low Voltage EVM Bldc Motor Components will describe the individual boards High-Voltage Hardware Set Configuration High-Voltage Hardware System Configuration Manual Motorola document order number Described in MC68HC908MR32 Control Board User’sSee References Low-Voltage Evaluation Motor Hardware Set Configuration Low-Voltage Evaluation Motor Hardware System Configuration Low-Voltage Hardware Set Configuration System configuration for low-voltage hardware set is shown Low-Voltage Hardware System Configuration References All HW Sets Components1 MC68HC908MR32 Control Board 4shows a block diagram of the board’s circuitry Electrical characteristics in -1apply to operation at 25C 1 3-Phase AC/BLDC High Voltage Power Stage Electrical Characteristics of Control BoardHigh-Voltage Hardware Set Components Phase AC High Voltage Power Stage Electrical Characteristics of Power Stage Optoisolation Board Electrical Characteristics of the Optoisolation Board Electrical Characteristics Low-Voltage Evaluation Motor Hardware Set Components 3 3-phase Bldc High Voltage Motor with Motor BrakeEVM Motor Board 2 3-phase Low Voltage EVM Bldc Motor Electrical Characteristics of the EVM Motor BoardElectrical Characteristics of the EVM Motor Board Characteristics of the Bldc motor 1 3-Ph AC/BLDC Low Voltage Power Stage Low-Voltage Hardware Set Components Block Diagram 2 3-phase Bldc Low Voltage Motor with Motor Brake Section Introduction Data Flow Main Software Flowchart State DiagramSoftware Design Data Flow Important system variables are listed in Table Software Variables and Defined ConstantsSoftware Variables Sys3Def Start/Stop Switch Reading and Start/Stop DecisionProcess Measurement Main Data Flow Part1 Process Fault Control Fault Stop Process Back, EMF Zero Crossing Sensing Freescale Semiconductor, Inc Main Data Flow Part 2 Alignment, Starting Process Desired Speed Setting Closed Loop Control System Bldc Speed Control and Calculation Processes Commutation and Zero Crossing Preset and SetProcess Alignment Control Main Software Flowchart Bldc Commutation and Zero Crossing Selection Main Software Flowchart Freescale Semiconductor, Inc Main Software Flowchart Main Software Loop Freescale Semiconductor, Inc Freescale Semiconductor, Inc State Diagram Software Flowchart Interrupts Application State Transitions Initialize Application State diagram for this software is shown in FigureInitialize MCU Stand-By Freescale Semiconductor, Inc Stand-by State Align State Starting Commutation Time Calculation Freescale Semiconductor, Inc 10. Back-EMF Acquisition Set Service of CommutationCommutation Time Calculation Running State Service of Received Back-EMF Zero CrossingExplained in 5.5.5 Back-EMF Acquisition State Over Current 11. Running State 12. Stop State Fault State Stop State Software Files Implementation NotesSee Figure Software files and structure are described in section Bldc Commutation and Zero Crossing Selection Preset Bldc Commutation and Bemf Zero Crossing SelectionSet Bldc Commutation and Bemf Zero Crossing Selection PWM Duty Cycle Bldc Speed Control and CalculationDesired Speed Calculation PWMValMax = DUTYPWMMAX*MCPWMMODULUS Timers Timer Function TIMACh3Int Designer Reference Manual DRM028 Rev 108 Software Design Minimal Application Speed User GuideApplication Suitability Guide Motor’s nominal speed Voltage Closed Loop Maximal Application SpeedMotor Suitability Mutual Inductance Designer Reference Manual DRM028 Rev 112 User Guide Hardware Configuration Application Hardware and Software ConfigurationHardware setups are shown in -1, -2, High-Voltage Hardware Set Configuration Low-Voltage Evaluation Motor Hardware Set Configuration Low-Voltage Hardware Set Configuration Controller Board Settings EVM board settings are the same for all hardware platforms EVM Board SettingsSoftware Setup Application HC08 Software Files \bldczerocros08MR32\sources\bldc08.c, main program Application PC Master Software Control Files Build Software ExecutionExecute from Evaluation Board Bldczerocros08mr32MMDS.sx is generated When the software is built, the S-record fileExecute from Pre-programmed MCU Application Control Manual Operating Mode PC Master Software Remote Operating Mode PC Master Software Control Window For More Information On This Product Tuning for Customer Motor User Guide Tuning for Customer Motor Follow-up for Software Customizing to Customer Motor Follow-up for Advanced Software Customizing To have PC master software installed on your PC computer Start the PC master software parameters tuning application 11. PC Master Software Parameters Tuning Control Window Software Parameters Setting Follow-up Labels in the File const.h \bldczerocros08MR32\sources\constcustlv.h, definitions for Software Customizing to Power StageParameters File Selection Example of Software Customizing to Hardware Current Setting Hardware Customizing Voltage Setting Hardware CustomizingRange 0,infinity Example of Software Customizing to Hardware Modified maximal measurable voltage is 55 V, so set Detailed description starts here Software Customizing to Motor Voltage and Current SettingsMaximal and Minimal Voltage Limits Setting Range 0,VOLTRANGEMAX Maximal and Minimal Current Limits Setting Range 0,CURRENTRANGEMAXA Current during alignment state before motor starts Α Alignment Current and Current Regulator SettingRange 0,8 Set constcustx.h Parameters Tuning with PC Master Software Project FileFrom Evaluation Board 12. PC Master Software Current Parameters Tuning Window Designer Reference Manual DRM028 Rev 142 User Guide MUSTCHANGEEXPERnn in file constcustx.h Commutation Parameters Commutation time period to discharge coil current ∝s Start-up Constants and Maximal Commutation Period Maximal commutation period limit ∝s Start-up PeriodRange -128,127 Constcustx.h Set #define Percmtstartus in constcustx.h Alignment Current and Current Regulator Setting 6.5.4.3Constcustx.h Ensure Percmtstartus =PERCMTMAXUS /2 #define Speedpiregigain Constcustx.h file 13. PC Master Software Start Parameters Tuning Window Number of commutations per motor revolution Software Customizing to Motor Speed Control SettingRange 0,255 Minimal speed of the drive rpm Maximal speed range rpmRange 0,SPEEDRANGEMAXRPM Speedminrpm = 0.07 to 0.5SPEEDMAXRPM User Guide 153 Execute from Evaluation Board Remote Operating Mode Set PC master software control mode and start motor seeStart motor see Application Control and PC Master Software PWM frequency setting is provided by PWM Frequency and Current Sampling Period SettingFor the PWM frequency setting, follow the label PWM Frequency PWM period = Periodpwmus = SETPERPWM*2 EQ PWM Frequency SettingCurrent Sampling Period PERCST1US = Periodpwmus * Setpercs ∝s Conclusion Software Parameters Setting and TuningCANCHANGEPERCURSAMPn in const.h file Current Sampling Instant User Guide 159 Designer Reference Manual DRM028 Rev 160 User Guide Appendix A. References Motor using MC68HC705MC4 document order number AN1627, Motorola Appendix B. Glossary SG40N Glossary Serial communications interface module SCI a module that Designer Reference Manual DRM028 Rev 166 Glossary Freescale Semiconductor, Inc HOW to Reach US USA/EUROPE/LOCATIONS not Listed