A Novel Torque Quality Improvement of an Asymmetric Windings Permanent-Magnet Synchronous Motor

This paper introduces a new control approach to improve the output torque quality of a surface-mounted permanent-magnet synchronous motor with asymmetric windings. The impact of the asymmetry is reflected in the newly developed mathematical model of the motor based on dq0 voltages, flux linkages, and torque. Using this model, a control strategy based on vector control technique is proposed. This algorithm aims to eliminate the zero-sequence current, thereby improving the motor performance. The capability of the proposed algorithm has been demonstrated via simulation and experimental results.

I. Introduction

Permanent magnet (PM) synchronous motors have been used in wide range of industrial applications after the developments in power electronics, microcontrollers, and drive systems. The introduction of the high-strength Neodymium Iron Boron (NdFeB) PMs [1]–[3] enabled the PM motors to become a competitive candidate for various applications due to their high torque–current ratio, high power density, and high efficiency. However, one of the inherited characteristics of the PM motors is torque ripple. This ripple is parasitic, and can lead to mechanical vibration, acoustic noise, and problems in drive systems. Minimizing this ripple is of great importance in the design of PMSMs. Different techniques for torque ripple minimization have been proposed in the literature, which can be classified into two broad areas. First one is mainly from design based and the second group includes the drive and control concepts.