Self-Calibration of Phase Current Sensors with Sampling Errors by Multipoint Sampling of Current Values in a Single PWM Cycle

The accuracy of current sensors is most crucial for the performance of an interior permanent magnet synchronous motor (IPMSM) drive. However, it may have sampling errors that are unavoidable for an actual drive. Therefore, to cope with this problem, in this article, a self-calibration strategy for phase-current sensors is proposed by utilizing the proposed topology and the correlation among the multiple current values obtained by current sampling values during one single pulsewidth modulation cycle, making minor changes for the cablings of the conventional current sensors in the premise of not affecting the normal operation of the drive, and abandoning complex observers or filters for easing the computational burden. Besides, its effectiveness was verified by the experimental results on a 5-kW IPMSM motor prototype, which showed that such sampling errors could be well estimated and eliminated.