Dual-Space Vector Control of Open-End Winding Permanent Magnet Synchronous Motor Drive Fed by Dual Inverter

This paper proposes a dual-space vector control scheme for the open-end winding permanent magnet synchronous motor (OEW-PMSM) drive fed by the dual inverter with a single dc supply. Potential zero-sequence current in the open-end winding drive system has to be considered since it causes circulating current in the winding and leads to high current stress of power semiconductor devices and high losses. Zero-sequence current in open-end winding ac motor drives is usually caused by the zero-sequence voltage, and therefore switching combinations which do not produce zero-sequence voltage are used to synthesize the reference voltage in existing methods. But even so, the zero-sequence voltage can also be produced by the dead time of the inverter. In order to suppress zero-sequence current in the OEW-PMSM drive, a dual-space vector control scheme is proposed and a novel dual-inverter space vector pulse width modulation (PWM) with the zero-sequence voltage reference is employed to regulate system zero-sequence voltage in this paper. Compared with existing dual inverter PWM strategies, the novel algorithm build a regulation mechanism for the zero-sequence voltage. The proposed method is compared with the conventional vector control by simulations and experiments, and the results shown that the proposed scheme can suppress zero-sequence current effectively.

I. Introduction

Permanent magnet synchronous motor (PMSM) drives are increasingly used in electric vehicles, aerospace, and military applications due to their excellent performance such as high power density, high efficiency, and good controllability. However, conventional three-phase star-connected winding motor drives have poor fault-tolerant capabilities. In this case, open-end winding ac motor drives fed by dual inverters have been interested in [1]–[7]. The dual inverter composed of double two-level inverters can produce space vector locations identical to that of a three-level inverter. So, an increase of dc-link voltage utilization in the open-end winding topology is achieved comparing with the two-level inverter fed star-connected winding topology. Further, additional diodes and capacitors like in the diode clamped and flying capacitor inverters are not required, and consequently capacitor voltage balancing can be avoided. Additionally, fault tolerance is improved, since the current in each phase of open-end winding motors can be controlled separately. Therefore, open-end winding ac motor drives are widely used in electric vehicles [8]–[10], high-power electric propulsion [11], [12] , aircraft starter-generator [13], and wind generation systems [14]–[16].