3-Phase BLDC Motor Sensorless Control Using MC56F8013

Motor Related ParametersFor a detailed explanation, see 7.5.3.3 COEF_RUN_CMT_PRECOMP_FRAC.7.5.2.6 COEF_START_CMT_PRECOMP_LSHFTCoefficient for calculating the commutation preset period.This coefficient is used with COEF_START_CMT_PRECOMP_FRAC to buildCOEF_START_CMT_PRECOMP. See 7.5.2.5 COEF_START_CMT_PRECOMP_FRACThis constant has the same function as COEF_RUN_CMT_PRECOMP_LSHFT, where one is for the runcommutation stage and one is for the start commutation state.For a detailed explanation, see 7.5.3.3 COEF_RUN_CMT_PRECOMP_FRAC.7.5.2.7 COEF_START_HLFCMTCoefficient for calculating the commutation period, after zero crossing is detected.This constant has the same function as COEF_RUN_HLFCMT, where one is for the run commutationstate and one is for the start commutation state.For a detailed explanation, see 7.5.3.5 COEF_RUN_HLFCMT.7.5.2.8 COEF_START_TOFFCoefficient for calculating the period Toff (where back-EMF zero crossing is not detected during start).This constant has the same function as COEF_RUN_TOFF, where one is for the run commutation stateand one is for the start commutation state.For a detailed explanation, see 7.5.3.6 COEF_RUN_TOFF.7.5.2.9 MIN_ZCROSOK_STARTMinimum number of zero crossing OK commutation to finish the BLDC starting phase.After this number of zero crossings is detected, the start commutation state ends and the run commutationstate begins.7.5.3 Run Parameters7.5.3.1 Parameter SummaryParameters for run are listed and explained in Table 7-6.3-Phase BLDC Motor Sensorless Control using MC56F8013, Rev. 0Freescale Semiconductor 81