一种弱磁扩速下的异步电机磁链观测和速度辨识

针对异步电机在高速弱磁下的运行特点,提出了一种基于弱磁下的高性能的磁链观测方法。该方法在基于转子磁链定向电流模型下,设计了一个可以补偿磁链观测误差的补偿器,解决了弱磁条件下励磁磁场变化而导致磁链观测不准的问题。在改进磁链观测的基础上,运用了易于在定点芯片上实现的转速辨识算法,估算出电机转速。最后将结合改进磁链观测的速度估计器应用到无速度传感器矢量控制系统中,仿真结果表明,这种方法实现方便,能够在弱磁高速下准确的辨识磁链和转速估计,提高控制系统的动态性能。

A Flux Observer and Speed Identification of AC under Field Weakening

According to the character of induction motor under the high speed field weakening operation, a new method of good-performance flux observer is proposed based on the improved voltage model. Based on the current model in the rotor flux orientation, a flux observer compensator is designed. It solves the problem of the inaccurate flux observer because of the variable excitation field. According to the flux, the rotor speed is estimated using the simple and easy identification algorithm on Fixed-chip. Finally, the method combined with the flux observer and speed estimator is applied in the speed senseless vector control system. The simulation results show that the method is easy to implement, and can improve the accuracy of the observer speed and improve the performance of the control system.