感应电动机间接磁场定向控制系统振荡的功率谱分析

ANALYSIS OSCILLATIONS IN INDIRECT FIELD ORIENTED CONTROL OF INDUCTION MOTOR VIA POWER SPECTRA

在感应电动机间接磁场定向控制(IFOC)系统中,若转子电阻不能正确估计并且PI速度调节器的参数设置不当,可能因出现Hopf分岔而导致系统振荡,由转子时间常数估计误差和阻尼比、无阻尼自振频率的关系导出了发生Hopf分岔的参数条件,对IFOC系统发生振荡时的时间响应进行了功率谱分析。结果表明,IFOC系统蕴涵丰富的动力学特性,在不同参数条件下,可以是稳定的,也可以产生周期振荡或混沌振荡,这一方面为避免振荡,设计一个常规的稳定电动机传动系统提供了理论依据;另一方面,对感应电动机这一工程中广泛应用的驱动源的不规则运动和混沌运动特性的研究,将为利用其振荡特性提高感应电动机动态响应和运行效率打下基础。

In indirect field oriented control (IFOC) of induction motor, with poor PI speed controller setting, oscillations may occur due to the existence of Hopf bifurcation provided the motor rotor resistance can not be exactly estimated. Conditions for the happening of Hopf bifurcation are deduced from the relationships among rotor time constant estimating error, natural undamped frequency and damping ratio of the system. The characteristic of oscillations is described by power spectra oftime series. Research results show that there are abundant dynamics in IFOC drive. In different parameter cases the system exhibit stability, periodic or even chaos. The study lays the foundation for either avoiding oscillations to design a stable conventional induction motor drive, or using oscillations to improve dynamic performance and efficiency of drive.