3-Phase BLDC Motor Sensorless Control Using MC56F8013

TuningTable 7-3. Alignment Parameter SummaryName Description Unit Range DefaultFreeMasterLocationPER_ALIGNMENT_SDuration of the alignmentcommutation state.s(seconds)0.1–12.0 0.5Control >AlignmentCUR_ALIGN_DESIRED_A Alignment current. A 0.1–3.0 1.5Control >AlignmentALIGNMENT_STEP_CMP_ABCPWM pattern applied to themotor during alignment, whenthe desired speed is positive.N/A0 [A+ B-]–5 [A+ C-]5 [A+ C-]Control >AlignmentALIGNMENT_STEP_CMP_ACBPWM pattern applied to themotor during alignment, whenthe desired speed is negative.N/A0 [A+ B-]–5 [A+ C-]4 [B+ C-]Control >Alignment7.5.1.2 PER_ALIGNMENT_SThe duration of the alignment state of commutation, in seconds.The duration of alignment must be long enough to stabilize the motor, before it starts.For tuning, it is recommended to keep the duration of the alignment state sufficiently long to ensure thatalignment is achieved. When it has been seen that the motor is aligned properly, this duration can beshortened, as long as it enables proper alignment.7.5.1.3 CUR_ALIGN_DESIRED_AValue of the alignment current.The alignment current PI controller tries to keep the DC-bus current at this value, during the alignmentcommutation state.The alignment current can be as high as the nominal current of the motor.7.5.1.4 ALIGNMENT_STEP_CMP_ABCThe PWM pattern applied to the motor during the alignment state, when the desired speed is positive.This parameter can be a value from 0 to 5, where every value corresponds to a PWM pattern, as follows.0: A top, B bottom1: B bottom, C top2: C top, A bottom3: A bottom, B top4: B top, C bottom5: C bottom, A topThese patterns are defined by the BldcZC_Cmt_StepTable array in bldcdrv.c.7.5.1.5 ALIGNMENT_STEP_CMP_ACBThe PWM pattern applied to the motor in the alignment state, when the desired speed is negative.This parameter can be a value from 0 to 5, where every value corresponds to a PWM pattern, as follows.3-Phase BLDC Motor Sensorless Control using MC56F8013, Rev. 078 Freescale Semiconductor