High Robustness Current Measurement Error Compensation of SPMSM Drives Based on Discrete Fourier Transform

Accurate measurement of current feedback is an important prerequisite for high performance permanent magnet synchronous motor (PMSM) drive systems. For the actual control system, due to the thermal drift, aging, nonlinearity and some other factors of the current sensors and the corresponding conditioning circuits, current measurement error will occur and correspondingly will result in torque and speed ripples. To overcome this issue, an online current measurement error compensation (CMEC) method for PMSM drive system is proposed in this paper. Firstly, the influence of different kinds of current measurement errors, the offset error and scaling error, is analyzed from the perspective of open loop control. Secondly, a Discrete Fourier Transform (DFT) based CMEC method is proposed. Finally, the effectiveness of the proposed method is validated on a 1kW commercialized servo motor test rig, results show that the proposed method can reduce 80% of the current ripple.