Compensation method of DC-link Current Integral Deviation for Sensorless Control of Three-phase BLDC Motor

Aiming at the problem of sensorless commutation deviation of brushless DC motors with three-phase non-ideal back EMF, a new sensorless control method based on DC-link current is proposed to achieve optimal commutation and reduce the system Power consumption. Detection errors and calculation errors caused by non-ideal conditions and parameter changes will seriously affect motor commutation, which will increase motor losses and reduce motor efficiency. The relationship between the commutation point displacement and the DC-link current is analyzed, and the DC-link current deviation integral method is proposed. The initial commutation error can be calculated in a conduction interval, and then online commutation correction can be used to compensate the remaining error in the subsequent conduction interval. Experimental results show that this method can achieve high-precision deviation correction and optimal commutation at each commutation point when the three-phase reverse electromotive force is not ideal.