基于定子电流和转子磁链点乘的异步电机转子时间常数在线辨识算法稳定性分析

Stability Analysis of a Dot Product of Stator Currents and Rotor Flux Based Online Rotor Time Constant Updating Algorithm in Induction Motor Drives

在异步电机间接矢量控制系统中,电机定子电流和转子磁链的点乘值可以作为设定物理量来构成一个模型参考自适应系统,实现转子时间常数的在线辨识。但是模型参考自适应系统中比例积分调节器参数的选取缺乏理论依据,同时该方案的稳定性也需要深入分析。为此,该文首先建立该点乘值的稳态误差方程,揭示该方案的物理本质;然后借助李雅普诺夫线性化理论,建立该方案的小信号模型,并指出当转子磁链估计准确时,点乘方案是电机全运行区间内稳定的;同时分析比例积分调节器参数对转子时间常数辨识动态性能的影响,这为调节器参数的优化选取提供理论依据。仿真和实验结果证明该文理论分析的正确性。

The dot product of stator currents and rotor flux can be chosen to form a model reference adaptive system （MRAS） to achieve online estimation of the rotor time constant in an induction motor drive with indirect field oriented control （IFOC）. However, the selection of the adaptation proportional- integral （PI） gains in the MRAS lacks theoretical basis and the stability of such a system is still not clarified. Therefore, the steady-state error of the dot product of stator currents and rotor flux was established in this paper, revealing its physical meaning. Then a small-signal model Of the estimation system was developed with Lyapunov linearization theory. It was revealed that the MRAS utilizing the dot product of stator currents and rotor flux was stable over the whole operating range if rotor flux was obtained accurately. Moreover, the effect of the PI gains in the MRAS on the dynamic estimation performance was analyzed, supplying the theoretical basis for further optimization of the adaptation gains. Simulation and experimental results have confirmed the validity of the proposed analysis.