Rapid estimation and compensation method of commutation error caused by Hall sensor installation error for BLDC motors

Abstract

Hall sensors provide significant commutation signals for brushless DC (BLDC) motors. However, installation errors of Hall sensors are almost inevitable for BLDC motors, which can lead to commutation errors, further current ripples and torque ripples. Meanwhile, abnormal diode conducting in inactive phase can be aroused by large commutation errors at high speed. Therefore, the commutation errors make a negative influence on motor efficiency and degrade the performance of BLDC motors. Here, a simple and fast method to estimate the commutation error is proposed. Based on the analysis of the commutation process under commutation error, only the turn-off phase current at the commutation instant is required for the estimation of delayed commutation error, while only the time interval of the turn-off phase current decreasing to zero after commutation instant is needed when advanced commutation occurs. In order not to affect the dynamic performance of a BLDC motor, this study utilises a straightforward compensating method of commutation error. The experimental results represent that the proposed method is effective at different speeds, load torques, and under load-variation with good transient performance.