Flux-weakening control of permanent magnet synchronous motor used in electric vehicles

Described the surface-mount permaent magnet synchronous motor used in electric vehicles operation principle, introduce the current limit trajectory and the voltage limit trajectory based on its mathematical model, Flux-weakening control extends the speed range of the machine effectively. Conventional flux-weakening speed control above the rate speed, the q-axis current and d-axis current coupling deeply, difficult to control. This paper presents a novel control strategy, by combining closed-loop control using the motor torque and speed with the pre-calculated tables, coming q-axis voltage for a given value, and through the given speed and feedback speed could calculate the d-axis voltage value. Through the MATLAB/simulink realization of the kind of control method, and in engineering practice has been verified.