A specially designed EV PM motor drive

Abstract

A specially designed electric vehicle (EV) PM motor drive is developed. The new PM phase decoupling brushless DC motor possesses the advantages of high power density, high efficiency, simple mathematical model and good torque performance. Meanwhile, a high speed efficiency-optimising control scheme is proposed for the motor. The high speed constant power operation is achieved in such a way that the transformer EMF is used to counteract the enlarged rotational EMF when the motor operates above the base speed. To obtain the efficiency optimising control, the advanced conduction angle is adaptively adjusted to minimise the system losses for a given operating point in the high speed region. Both simulation and experimental results are given in the paper.