稀土永磁同步电动机最佳效率调速

考虑到稀土永磁同步电动机电枢电阻及电机的凸极效应，根据电机矢量图推出了其基本方程，通过控制特性分析，提出了最小电流法并采用Ｕ／ｆ，曲线自学习实现了恒转矩控制时任意频率下的最佳效率调速，给出了实际电路以及该方法的优越性。

On Optimal Efficiency in REPMSM Speed Control

In China, the open-loop variable-frequency adjusting speed technique has been successfully used to control REPMSM (rare earth permanent magnetic synchronous motor),but in this system there are still two weaknesses: (1) the motor efficiency is not the haghest possible ; (2) the voltage-frequency control curve is not quite satisfactory. With a view to reducing these two weaknesses, we consider the influences of the armature resistance and the salient pole effect which were tenored in the past.First we derive REPMSM fundamental equations (eqs. 4 through 12) from the vector diagram (Fig. lb); then draw its V-shaped control characteristic curve in Fig. 2. Analysis shows that REPMSM current is not minimum at cos=1. Therefore, from the viewpoint of reducing the copper loss and the demagnetizing effect of the armature reaction, we conclude that the control of REPMSM should adopt minimum current control to obtain optimal efficiency. The single-chip microcomputer is used to seek the minimum current in a certain steady frequency; it can also, through self-learning, satisfy the fine coordination of the controller and REPMSM, thus making the voltage-frequency curve a little moresatisfactory.