A Reference Voltage Self-Correction Method for Capacitor Voltage Offset Suppression of Three-Phase Four-Switch Inverter-Fed PMSM Drives

Abstract

This paper proposes a capacitor voltage offset suppression method based on reference voltage self-correction for a three-phase four-switch (TPFS) inverter-fed permanent magnet synchronous motor (PMSM) drive system to improve the motor control performance. Firstly, the αβ-axis reference voltage deviation caused by capacitor voltage offset is analyzed, and the relationship between the voltage to be compensated and the offset is obtained. Then, the capacitor voltage offset is calculated according to the motor speed, rotor position, current vector amplitude, and capacitance on the capacitor bridge arm of the TPFS inverter. Finally, the reference voltage is corrected according to the voltage to be compensated and the capacitor voltage offset. This method is simple and easy to implement, and there is no need to add voltage sensors or filters in the system to extract the capacitor voltage offset, and there is no complex parameter adjustment. The effectiveness of the proposed method is verified by experiments on a 20 kW interior permanent magnet synchronous motor.

Keywords

• three-phase four-switch inverter
• permanent magnet synchronous motor (PMSM)
• capacitor voltage offset suppression
• reference voltage self-correction