Motorola M68HC08 manual

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

Brushless DC Motor Control Theory

Figure 3-10. Distributed Back-EMF by Unbalanced

Capacity Coupling

Channel 1 in Figure 3-11shows the disturbed “branch” voltage, while the other phase (channel 2) is not affected because it faces balanced mutual capacitance. The unbalance was purposely made by adding a small capacitor on the motor terminals, in order to better demonstrate the effect. After the unbalance was removed the “branch” voltage is clean, without any spikes.

DRM028 — Rev 0		Designer Reference Manual

MOTOROLA	BLDC Motor Control	35
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Motorola M68HC08 manual Distributed Back-EMF by Unbalanced Capacity Coupling

Contents

Freescale Semiconductor, Inc M68HC08 For More Information On This Product Designer Reference Manual Rev Sensorless Bldc Motor Control Using MC68HC908MR32 Revision history List of Sections List of Sections Table of Contents Table of Contents Title List of Figures List of Figures List of Tables List of Tables Application Functionality ContentsBenefits of the Solution Introduction Introduction System Concept System Description System Description System Specification Software Specifications Software SpecificationSoftware written in C language specifications are listed Software parameter tuning to a customer motor High-Voltage Hardware Set Specification Hardware and Drive Specifications Motor -Brake Set High Voltage Hardware Set Specifications Low-Voltage Hardware Set Specification Low-Voltage Evaluation Hardware Set SpecificationLow Voltage Evaluation Hardware Set Specifications Low Voltage Hardware Set Specifications Bldc Motor Targeted by This Application Bldc Motor ControlBrushless DC Motor Control Theory Semiconductor, Inc Bldc Motor Control Brushless DC Motor Control Theory Bldc Motor Back EMF and Magnetic Flux Why Sensorless Control? 2 3-Phase Bldc Power Stage Power Stage Motor Topology Indirect Back EMF Sensing Stator Winding Equations Same expressions can also be found for phase a and B Effect of Mutual Inductance Phase Voltage Waveform Mutual Inductance Effect Detail of Mutual Inductance Effect Effect of Mutual Phase Capacitance Mutual Capacitance Model 10. Distributed Back-EMF by Unbalanced Capacity Coupling 11. Balanced Capacity Coupling Back-EMF Sensing Circuit Inc Alignment Starting Back-EMF Acquisition Running Used Control TechniqueSensorless Commutation Control Alignment 14. Commutation Control Stages Running 15. Alignment Freescale Semiconductor, Inc Commutation time calculation is shown in Figure Running Commutation Time Calculation 17. Bldc Commutation Time with Zero Crossing Sensing Service of received back-EMF zero crossing Where Starting Back-EMF Acquisition Freescale Semiconductor, Inc 18. Vectors of Magnetic Fields 19. Back-EMF at Start Up Computation coefficients are different Starting Commutation Time CalculationRunning Commutation Time Calculation, but the following PC Master Software Application ControlSpeed Control PC Master Software Communication Commands Communication with PC Master Software Specifications Name Type Representing Description Range PC Master Software API Variables BIT6 Reserved MotorStatusDef, FailureDef BIT2 Reserved SpeedRangeMaxRPM*PerSpeedMAXRange/PerZCrosFltT2 PerSpeedMAXRange and zero crossing period PerZCrosFltT2 Freescale Semiconductor, Inc For High-Voltage Hardware Set cofiguration System Configuration and DocumentationHardware Design MC68HC908MR32 Control Board Components will describe the individual boards For Low-Voltage Evaluation Motor Hardware Set configurationEVM Motor Board Phase Low Voltage EVM Bldc Motor Low-Voltage Hardware Set configuration High-Voltage Hardware System Configuration High-Voltage Hardware Set Configuration See References Described in MC68HC908MR32 Control Board User’sManual Motorola document order number Low-Voltage Evaluation Motor Hardware System Configuration Low-Voltage Evaluation Motor Hardware Set Configuration System configuration for low-voltage hardware set is shown Low-Voltage Hardware Set Configuration Low-Voltage Hardware System Configuration 1 MC68HC908MR32 Control Board All HW Sets ComponentsReferences Electrical characteristics in -1apply to operation at 25C 4shows a block diagram of the board’s circuitry High-Voltage Hardware Set Components Electrical Characteristics of Control Board1 3-Phase AC/BLDC High Voltage Power Stage Phase AC High Voltage Power Stage Optoisolation Board Electrical Characteristics of Power Stage Electrical Characteristics Electrical Characteristics of the Optoisolation Board EVM Motor Board 3 3-phase Bldc High Voltage Motor with Motor BrakeLow-Voltage Evaluation Motor Hardware Set Components Characteristics of the Bldc motor Electrical Characteristics of the EVM Motor BoardElectrical Characteristics of the EVM Motor Board 2 3-phase Low Voltage EVM Bldc Motor Low-Voltage Hardware Set Components 1 3-Ph AC/BLDC Low Voltage Power Stage Block Diagram Section 2 3-phase Bldc Low Voltage Motor with Motor Brake Data Flow Data Flow Main Software Flowchart State DiagramSoftware Design Introduction Software Variables Software Variables and Defined ConstantsImportant system variables are listed in Table Process Measurement Start/Stop Switch Reading and Start/Stop DecisionSys3Def Process Back, EMF Zero Crossing Sensing Main Data Flow Part1 Process Fault Control Fault Stop Freescale Semiconductor, Inc Main Data Flow Part 2 Alignment, Starting Closed Loop Control System Process Desired Speed Setting Process Alignment Control Processes Commutation and Zero Crossing Preset and SetBldc Speed Control and Calculation Bldc Commutation and Zero Crossing Selection Main Software Flowchart Main Software Flowchart Freescale Semiconductor, Inc Main Software Flowchart Main Software Loop Freescale Semiconductor, Inc Freescale Semiconductor, Inc Software Flowchart Interrupts State Diagram Application State Transitions Stand-By State diagram for this software is shown in FigureInitialize MCU Initialize Application Freescale Semiconductor, Inc Stand-by State Align State Starting Commutation Time Calculation Freescale Semiconductor, Inc 10. Back-EMF Acquisition Commutation Time Calculation Service of CommutationSet Explained in 5.5.5 Back-EMF Acquisition State Service of Received Back-EMF Zero CrossingRunning State Over Current 11. Running State Stop State 12. Stop State Fault State Software files and structure are described in section Implementation NotesSee Figure Software Files Set Bldc Commutation and Bemf Zero Crossing Selection Preset Bldc Commutation and Bemf Zero Crossing SelectionBldc Commutation and Zero Crossing Selection PWMValMax = DUTYPWMMAX*MCPWMMODULUS Bldc Speed Control and CalculationDesired Speed Calculation PWM Duty Cycle Timer Timers Function TIMACh3Int Designer Reference Manual DRM028 Rev 108 Software Design Motor’s nominal speed User GuideApplication Suitability Guide Minimal Application Speed Motor Suitability Maximal Application SpeedVoltage Closed Loop Mutual Inductance Designer Reference Manual DRM028 Rev 112 User Guide Hardware setups are shown in -1, -2, Application Hardware and Software ConfigurationHardware Configuration Low-Voltage Evaluation Motor Hardware Set Configuration High-Voltage Hardware Set Configuration Low-Voltage Hardware Set Configuration Controller Board Settings Software Setup EVM Board SettingsEVM board settings are the same for all hardware platforms Application HC08 Software Files \bldczerocros08MR32\sources\bldc08.c, main program Application PC Master Software Control Files Execute from Evaluation Board Software ExecutionBuild Application Control When the software is built, the S-record fileExecute from Pre-programmed MCU Bldczerocros08mr32MMDS.sx is generated PC Master Software Remote Operating Mode Manual 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 Start the PC master software parameters tuning application To have PC master software installed on your PC computer 11. PC Master Software Parameters Tuning Control Window Software Parameters Setting Follow-up Labels in the File const.h Example of Software Customizing to Hardware Software Customizing to Power StageParameters File Selection \bldczerocros08MR32\sources\constcustlv.h, definitions for Range 0,infinity Voltage Setting Hardware CustomizingCurrent Setting Hardware Customizing Modified maximal measurable voltage is 55 V, so set Example of Software Customizing to Hardware Range 0,VOLTRANGEMAX Software Customizing to Motor Voltage and Current SettingsMaximal and Minimal Voltage Limits Setting Detailed description starts here Range 0,CURRENTRANGEMAXA Maximal and Minimal Current Limits Setting Range 0,8 Alignment Current and Current Regulator SettingCurrent during alignment state before motor starts Α From Evaluation Board Parameters Tuning with PC Master Software Project FileSet constcustx.h 12. PC Master Software Current Parameters Tuning Window Designer Reference Manual DRM028 Rev 142 User Guide MUSTCHANGEEXPERnn in file constcustx.h Commutation time period to discharge coil current ∝s Commutation Parameters Start-up Constants and Maximal Commutation Period Range -128,127 Start-up PeriodMaximal commutation period limit ∝s Ensure Percmtstartus =PERCMTMAXUS /2 Alignment Current and Current Regulator Setting 6.5.4.3Constcustx.h Constcustx.h Set #define Percmtstartus in constcustx.h Constcustx.h file #define Speedpiregigain 13. PC Master Software Start Parameters Tuning Window Range 0,255 Software Customizing to Motor Speed Control SettingNumber of commutations per motor revolution Range 0,SPEEDRANGEMAXRPM Maximal speed range rpmMinimal speed of the drive rpm Speedminrpm = 0.07 to 0.5SPEEDMAXRPM User Guide 153 Execute from Evaluation Board Start motor see Application Control and PC Master Software Set PC master software control mode and start motor seeRemote Operating Mode PWM Frequency PWM Frequency and Current Sampling Period SettingFor the PWM frequency setting, follow the label PWM frequency setting is provided by Current Sampling Period PWM Frequency SettingPWM period = Periodpwmus = SETPERPWM*2 EQ Current Sampling Instant Conclusion Software Parameters Setting and TuningCANCHANGEPERCURSAMPn in const.h file PERCST1US = Periodpwmus * Setpercs ∝s User Guide 159 Designer Reference Manual DRM028 Rev 160 User Guide Appendix A. References AN1627, Motorola Motor using MC68HC705MC4 document order number SG40N Appendix B. Glossary 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