Detrimental effect elimination of current sensor accuracy uncertainty for high-precision position sensorless control of interior permanent magnet synchronous motor drives

The precision of position estimation is highly dependent on the accuracy of multiple current sensors, whereas the conventional error calibration strategies for current sensor accuracy uncertainty (SAU) problem have limitations regarding the position sensorless controlled drives. In order to solve this thorny problem, this article proposes a mutual calibration strategy for the multiple current sensors in an interior permanent magnet synchronous motor (IPMSM) drive. The proposed current sensor error calibration strategy takes full advantage of the correlation among the multiple current sensors themselves without using any complicated observers. Moreover, the traditional seven-segment space vector pulsewidth modulation technology is applied without modification. The only change is reflected in several sets of the artificially added current sampling points. The effectiveness of the proposed strategy is verified by experimental results on a 5-kW IPMSM motor prototype, which shows that the calibrated current sensors exhibit improved accuracy, and the position estimation accuracy is also guaranteed.