Motorola M68HC08 manual PerSpeedMAXRange and zero crossing period PerZCrosFltT2

Page 55

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

Application Control

The Sp_Input variable is used for speed control. In PC master software mode, it can be modified from PC master software (otherwise, it is set according to speed potentiometer value).

Desired speed [rpm] =

Sp_Input/255*(Speed_Max_RPM-Speed_Min_RPM) + Speed_Min_RPM

So, the required motor commutation period is determined by the Speed_Max_RPM and Speed_Min_RPM variables. These are chosen according to which optional board and motor set by the BLDC control MCU software.

The variable Speed_Range_Max_RPM determines scaling of the speed variables.

The actual speed of the motor can be calculated from

Per_Speed_MAX_Range and zero crossing period Per_ZCrosFlt_T2:

Actual speed [rpm] =

Speed_Range_Max_RPM*Per_Speed_MAX_Range/Per_ZCrosFlt_T2

The variable Commut_Rev can be used for calculation of the BLDC motor commutation period:

Commutation Period [s] = 60 / Actual Speed [rpm] / Commut_Rev

The variable Curr_Range_Max_cA determines scaling of the current variables. So, the actual dc-bus current is:

dc-bus current [A] = Curr / 256*Curr_Range_Max_cA / 100

DRM028 — Rev 0		Designer Reference Manual

MOTOROLA	BLDC Motor Control	55
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Contents Freescale Semiconductor, Inc M68HC08For More Information On This Product Designer Reference Manual Rev Sensorless Bldc Motor Control Using MC68HC908MR32Revision history List of Sections List of Sections Table of Contents Table of Contents Title List of FiguresList of Figures List of Tables List of Tables Application Functionality ContentsBenefits of the Solution IntroductionIntroduction System Concept System DescriptionSystem Description System Specification Software Specifications Software SpecificationSoftware written in C language specifications are listed Software parameter tuning to a customer motorHigh-Voltage Hardware Set Specification Hardware and Drive SpecificationsMotor -Brake Set High Voltage Hardware Set SpecificationsLow 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 Why Sensorless Control? 2 3-Phase Bldc Power StagePower Stage Motor Topology Indirect Back EMF Sensing Stator Winding EquationsSame expressions can also be found for phase a and B Effect of Mutual Inductance Phase Voltage WaveformMutual Inductance Effect Detail of Mutual Inductance Effect Effect of Mutual Phase CapacitanceMutual 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 Alignment 14. Commutation Control StagesRunning 15. AlignmentFreescale Semiconductor, Inc Commutation time calculation is shown in Figure Running Commutation Time Calculation17. Bldc Commutation Time with Zero Crossing Sensing Service of received back-EMF zero crossingWhere 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 PC Master Software Communication Commands Communication with PC Master Software SpecificationsName Type Representing Description Range PC Master Software API VariablesBIT6 Reserved MotorStatusDef, FailureDefBIT2 Reserved SpeedRangeMaxRPM*PerSpeedMAXRange/PerZCrosFltT2 PerSpeedMAXRange and zero crossing period PerZCrosFltT2Freescale Semiconductor, Inc For High-Voltage Hardware Set cofiguration System Configuration and DocumentationHardware Design MC68HC908MR32 Control BoardComponents 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 configurationHigh-Voltage Hardware System Configuration High-Voltage Hardware Set ConfigurationManual Motorola document order number Described in MC68HC908MR32 Control Board User’sSee References Low-Voltage Evaluation Motor Hardware System Configuration Low-Voltage Evaluation Motor Hardware Set ConfigurationSystem configuration for low-voltage hardware set is shown Low-Voltage Hardware Set ConfigurationLow-Voltage Hardware System Configuration References All HW Sets Components1 MC68HC908MR32 Control Board Electrical characteristics in -1apply to operation at 25C 4shows a block diagram of the board’s circuitry1 3-Phase AC/BLDC High Voltage Power Stage Electrical Characteristics of Control BoardHigh-Voltage Hardware Set Components Phase AC High Voltage Power Stage Optoisolation Board Electrical Characteristics of Power StageElectrical Characteristics Electrical Characteristics of the Optoisolation BoardLow-Voltage Evaluation Motor Hardware Set Components 3 3-phase Bldc High Voltage Motor with Motor BrakeEVM Motor Board 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 MotorLow-Voltage Hardware Set Components 1 3-Ph AC/BLDC Low Voltage Power StageBlock Diagram Section 2 3-phase Bldc Low Voltage Motor with Motor BrakeData Flow Data Flow Main Software Flowchart State DiagramSoftware Design IntroductionImportant system variables are listed in Table Software Variables and Defined ConstantsSoftware Variables Sys3Def Start/Stop Switch Reading and Start/Stop DecisionProcess Measurement Process Back, EMF Zero Crossing Sensing Main Data Flow Part1 Process Fault Control Fault StopFreescale Semiconductor, Inc Main Data Flow Part 2 Alignment, Starting Closed Loop Control System Process Desired Speed SettingBldc Speed Control and Calculation Processes Commutation and Zero Crossing Preset and SetProcess Alignment Control Bldc Commutation and Zero Crossing Selection Main Software FlowchartMain Software Flowchart Freescale Semiconductor, Inc Main Software Flowchart Main Software Loop Freescale Semiconductor, Inc Freescale Semiconductor, Inc Software Flowchart Interrupts State DiagramApplication State Transitions Stand-By State diagram for this software is shown in FigureInitialize MCU Initialize ApplicationFreescale 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 Stop State 12. Stop State Fault StateSoftware files and structure are described in section Implementation NotesSee Figure Software FilesBldc Commutation and Zero Crossing Selection Preset Bldc Commutation and Bemf Zero Crossing SelectionSet Bldc Commutation and Bemf Zero Crossing Selection PWMValMax = DUTYPWMMAX*MCPWMMODULUS Bldc Speed Control and CalculationDesired Speed Calculation PWM Duty CycleTimer TimersFunction TIMACh3Int Designer Reference Manual DRM028 Rev 108 Software Design Motor’s nominal speed User GuideApplication Suitability Guide Minimal Application SpeedVoltage 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, Low-Voltage Evaluation Motor Hardware Set Configuration High-Voltage Hardware Set ConfigurationLow-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 Application Control When the software is built, the S-record fileExecute from Pre-programmed MCU Bldczerocros08mr32MMDS.sx is generatedPC Master Software Remote Operating Mode Manual Operating ModePC 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 computer11. 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 forCurrent Setting Hardware Customizing Voltage Setting Hardware CustomizingRange 0,infinity Modified maximal measurable voltage is 55 V, so set Example of Software Customizing to HardwareRange 0,VOLTRANGEMAX Software Customizing to Motor Voltage and Current SettingsMaximal and Minimal Voltage Limits Setting Detailed description starts hereRange 0,CURRENTRANGEMAXA Maximal and Minimal Current Limits SettingCurrent 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 time period to discharge coil current ∝s Commutation ParametersStart-up Constants and Maximal Commutation Period Maximal commutation period limit ∝s Start-up PeriodRange -128,127 Ensure Percmtstartus =PERCMTMAXUS /2 Alignment Current and Current Regulator Setting 6.5.4.3Constcustx.h Constcustx.h Set #define Percmtstartus in constcustx.hConstcustx.h file #define Speedpiregigain13. 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 PWM Frequency and Current Sampling Period SettingFor the PWM frequency setting, follow the label PWM frequency setting is provided byPWM period = Periodpwmus = SETPERPWM*2 EQ PWM Frequency SettingCurrent Sampling Period Current Sampling Instant Conclusion Software Parameters Setting and TuningCANCHANGEPERCURSAMPn in const.h file PERCST1US = Periodpwmus * Setpercs ∝sUser Guide 159 Designer Reference Manual DRM028 Rev 160 User Guide Appendix A. References AN1627, Motorola Motor using MC68HC705MC4 document order numberSG40N Appendix B. GlossaryGlossary 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