Zero-Sequence Current Suppression Strategy for Five-Phase OW-PMSM With Reduced Common-Mode Voltage and Inverter Losses

Abstract

Zero-sequence current exists in five-phase open-winding permanent magnet synchronous motors (FPOW-PMSMs) with a common DC bus, resulting in harmonic current and system losses. Besides, the use of the dual-inverter increases inverter losses and induces a high-frequency common-mode voltage, damaging the bearing. This paper proposes a novel zero-sequence current suppression method for the FPOW-PMSM, which can reduce the inverter losses while decreasing the common-mode voltage. First, the average zero-sequence voltage equal to zero is considered a restriction to calculate the duration time of basis vectors. Five active vectors are selected to synthesize the reference voltage vector in each sector. Then, benefiting from abundant switching states redundancy, a novel switching states combination with minimum switching actions is proposed to reduce the common-mode voltage and inverter losses. Furthermore, the modulation range of the proposed modulation method is analyzed, indicating that the proposed method achieves considerable DC bus voltage utilization. Finally, the experimental results verify the effectiveness of the proposed method.