Virtual Viable Sampling Timing via CPWM-DPWM Switching for Current Measurement Errors Calibration in PMSM Drive

To solve the performance degradation caused by current measurement error (CME) of 2LVSI-permanent magnet synchronous motor drive system, additional current sampling points, auxiliary equipment, or more computing resources are often required in existing CME calibration methods. To cope with these challenges, a calibration strategy with virtual viable sampling timing via continuous pulse width modulation (CPWM)-DPWM modulation mode switching is proposed. Additional current sampling points and sampling point movement are not required by flexibly switching modulation mode to discontinuous pulse width modulation (DPWM). Only current closed-loop feedback values at routine sampling point are required for the CME estimation without the reference current, complex observers, and filters. Therefore, the proposed method can be used as a solution for CME with low hardware dependency and low computing complexity. Meanwhile, the effectiveness and practicability of the proposed method are verified by the experiments, which shows that the CME can be well estimated and eliminated.