Robust current control insensitive to gain deviation and offset of inverter DC-link current sensor for SPMSM

An AC servomotor is operated by current sensors. Owing to cost implications, it is often operated by an inverter system based on single DC-link current sensor. However, a current sensor sometimes has offset and gain variation caused by secular and thermal variation. When surface permanent magnet synchronous motor (SPMSM) drive system has the offset and the gain variation of current sensor, SPMSM has the current ripples and torque ripples. This paper proposes a new robust current control system insensitive to deviation and offset of current sensor for SPMSM. The proposed system tunes the current measurement gain deviation and realizes robust current control system. The proposed method suppresses q axis current errors by tuning the current measurement gains. Simulation results and experimental results confirm that the proposed method well suppresses the current sensor offset and the current sensor gain variation. Hence, the robust current control for SPMSM is always completed.