2004 Microchip Technology Inc.
DS00908A-page 29
AN908
// Rotor time constant in sec
MotorParm.fRotorTmConst = dfRotorTmConst;
// Basic loop period (in sec). (PWM interrupt period)
MotorParm.fLoopPeriod = dLoopInTcy * dTcy; //Loop period in cycles * sec/cycle
// Encoder velocity interrupt period (in sec).
MotorParm.fVelIrpPeriod = MotorParm.fLoopPeriod;
// Number of vel interrupts per velocity calculation.
MotorParm.iIrpPerCalc = diIrpPerCalc; // In loops
// Scale mechanical speed of motor (in rev/sec)
MotorParm.fScaleMechRPS = MotorParm.iScaleMechRPM/60.0;
// Scaled flux speed of motor (in rev/sec)
// All dimensionless flux velocities scaled by this value.
MotorParm.fScaleFluxRPS = MotorParm.iPoles*MotorParm.fScaleMechRPS;
// Minimum period of one revolution of flux vector (in sec)
MotorParm.fScaleFluxPeriod = 1.0/MotorParm.fScaleFluxRPS;
// Fraction of revolution per LoopTime at maximum flux velocity
MotorParm.fScaleFracRevPerLoop = MotorParm.fLoopPeriod * MotorParm.fScaleFluxRPS;
// Scaled flux speed of motor (in radians/sec)
// All dimensionless velocities in radians/sec scaled by this value.
MotorParm.fScaleFluxSpeed = 6.283 * MotorParm.fScaleFluxRPS;
// Encoder count rate at iScaleMechRPM
MotorParm.lScaleCntRate = MotorParm.iCntsPerRev * (MotorParm.iScaleMechRPM/60.0);
// ============= Open Loop ======================
OpenLoopParm.qKdelta = 32768.0 * 2 * MotorParm.iPoles * MotorParm.fLoopPeriod *
MotorParm.fScaleMechRPS;
OpenLoopParm.qVelMech = dqOL_VelMech;
CtrlParm.qVelRef = OpenLoopParm.qVelMech;
InitOpenLoop();
// ============= Encoder ===============
if( InitEncoderScaling() )
// Error
return True;
// ============= ADC - Measure Current & Pot ======================
// Scaling constants: Determined by calibration or hardware design.
ReadADCParm.qK = dqK;
MeasCurrParm.qKa = dqKa;
MeasCurrParm.qKb = dqKb;
// Inital offsets
InitMeasCompCurr( 450, 730 );
// ============= Current Model ===============
if(InitCurModelScaling())
// Error
return True;
