Motor controller with hall sensor output misalignment compensation using delayed or shifted commutation

Abstract

In a normal operating mode, a motor controller provides motor drive current to windings of a motor based on sensor signals to drive the windings in a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition in a given commutation state, then in a first driving step, the windings are momentarily driven according to an advanced commutation state, and during the first driving step, a reverse transition of the sensor signals to a state corresponding to a preceding commutation state is detected. Upon completion of the first driving step when such a reverse transition of the sensor signals is detected, then in a second driving step the windings are driven according to the preceding commutation state until a forward transition of the sensor signals is detected, and in a third driving step the windings are momentarily continued to be driven according to the same commutation state notwithstanding the forward transition of the sensor signals before normal operation is resumed.