Error Correction Strategy for Phase Current Reconstruction in Permanent Magnet Synchronous Motors With Single DC-Link Current Sensing

Permanent magnet synchronous motors(PMSM) can reduce volume and cost by using a single DC-link current sensor, and eliminate current sampling errors caused by multiple sensors. However, due to inconsistent current sampling moments and the inability to sample during zero-vector voltage, there will be errors in the reconstructed current. This paper analyzes the sources of reconstructed current errors in each sector under SVPWM control and summarizes the distribution patterns, finding that severe current jump phenomena occur during the switching of certain sectors. In response, a sampling error compensation method based on the prediction of periodic current final values is proposed. By calculating the slope of the current ripple, the sampling current is compensated to the end of the PWM cycle to eliminate sampling errors. Experimental results show that when the motor is at 200r/min, after the reconstructed current error is corrected, the average and maximum errors within a current cycle are reduced from 0.406 A to 0.288 A and from 1.593 A to 1.182 A, respectively, and the reconstructed current jump phenomenon is significantly alleviated.