无速度传感器异步电动机极低转速下的矢量控制

Vector control of a speed sensor-less induction motor at very low speed

在较低转速下,对异步电机转子磁通位置的观测比较困难,因此在定子边注入与电机控制量无关的高频信号,是提取转子磁通位置信息的有效方法之一。为此,该文分析了异步电机高频脉振信号注入下的电机模型,得到了异步电机同步参考坐标系下的阻抗不对称的特点,提出了磁通跟踪的方法,通过检测高频脉振信号注入时的响应电流,来观测转子的磁通位置,并以此为基础实现了无速度传感器异步电机极低转速下的矢量控制。实验结果表明,该方法在异步电机极低转速(包括零速)下能准确地观测出转子磁通位置,对电机的参数和负载变化具有鲁棒性,并且能够在零速时输出额定转矩。

The rotor flux angle of an induction machine at very low speed cannot easily estimated; therefore, an independent highfrequency signal was injected in to the terminal of an induction motor to estimate the flux angle. This paper presents an analysis of an induction motor model with a highfrequency fluctuating signal injection. When the highfrequency fluctuating signal is injected into the terminal of the induction motor, the difference between the impedance of the d and qaxis of the synchronous rotating reference frame can be measured. The rotor flux angle is then tracked by tuning the space vector of the highfrequency signal for vector control of induction motors at very low speed. Experimental results verify that the algorithm is robust against parameter variations and load changes and that the rated torque can be put out at very low speed including zero. 