Zero-Sequence Current Ripple Reduction Control in Open-End Winding Interior Permanent-Magnet Synchronous Motor Using Negative-Point-Connected Dual Inverter with Variable Voltage Capacitor

This paper presents a new inverter control method for reducing zero-sequence current ripples caused by pulse-width modulation (PWM) in a negative-point-connected dual inverter with a variable voltage capacitor. In this inverter, the DC-link voltage of the secondary inverter is controlled by charging and discharging the DC-link capacitor. When the DC-link voltage of the primary inverter is not equal to that of the secondary inverter, the zero-sequence current ripple caused by PWM increases. The proposed method reduces the zero-sequence current ripple using a PWM pattern that minimizes zero-sequence voltage fluctuations. The effectiveness of the proposed method is confirmed through numerical simulations.