Analysis of the stator flux linkage in permanent magnet synchronous motor direct torque control for EV

This paper discusses the relationship between the amplitude of stator flux linkage and the torque of interior permanent magnet synchronous motor (IPMSM). In order to change the load angle and the torque accordingly, the amplitude of stator flux linkage should be kept in restricted range. It also explains how to control the amplitude of stator flux linkage to get maximum torque by using direct torque control (DTC) under base speed, which improves the efficiency of the whole system. Simulation results have been presented and good performance has been achieved.

I. Introduction

THE key of high-performance operation of AC motor is the control of dynamic torque. After Depenbrock ^[1] brought forward direct torque control (DTC) method for induction motor, it has aroused wide attention of technique and industry. For the different operation principle between induction motor and synchronous motor, DTC has not been applied to synchronous motor say nothing of permanent magnet synchronous motor (PMSM) until Zhong. L^[2] put forward the theory of DTC of PMSM and primarily realized the scheme after ten years. Luukko. J^[3], J. Faiz^[4] and Chun Tian [5] did some further research on stator flux linkage, maximum torque/flux control and zero vector of DTC of PMSM, subsequently.