基于扩展卡尔曼滤波的直线感应电机速度观测

Speed observation of linear induction motor based on extended Kalman filter

为解决在直线感应电机(linear induction motor,LIM)高性能闭环控制系统取消速度传感器后,速度闭环中缺少速度反馈信息问题,在考虑LIM边端效应前提下,实现了一种基于扩展卡尔曼滤波算法的速度观测器。首先,基于考虑边端效应的三相LIM数学模型,推导出具有合适增益和协方差更新矩阵的扩展卡尔曼滤波观测器,并基于LIM的矢量控制系统,将观测器辨识的速度参数反馈到速度闭环系统中。然后,在Simulink中搭建带有速度观测器的LIM矢量控制系统模型,对观测器的辨识速度和电机实际速度进行对比。结果表明,利用辨识速度进行闭环控制可以保证系统稳定运行。在3种负载情况下,观测器的预测速度和实际速度之间的误差在0.51%~2.34%之间。对系统多种动态性能进行分析可知,基于扩展卡尔曼滤波观测器的LIM矢量控制系统,随着负载增大,预测速度的误差增大,推力误差减小,磁链幅值误差略微增大。因此,在考虑边端效应情况下,基于扩展卡尔曼滤波的观测器可以代替速度传感器实现空载和带载时的三相LIM控制。

In order to solve the problem of lacking velocity feedback information in the velocity closed-loop control system for linear induction motors(LIM) after cancelling the velocity sensor,a velocity observer based on the extended Kalman filtering algorithm has been implemented,considering the end edge effect of LIM.Firstly,based on the mathematical model of three-phase linear induction motor considering edge effect,an extended Kalman filter observer with appropriate gain and covariance update matrix is derived.Based on the vector control system of LIM,the speed parameters identified by the observer are fed back to the speed closed-loop system.Then,the vector control system model of linear induction motor with speed observer is built in Simulink,and the identification speed of observer is compared with the actual speed of motor.Finally,the results show that the closed-loop control using the identification speed can ensure the stable operation of the system.Under three kinds of loads,the error between the predicted speed and the actual speed of the observer is form 0.51% to 2.34%.The various dynamic performance of the system reveals that the LIM vector control system based on the extended Kalman filter observer increases prediction velocity error and decreases thrust error with increasing load.However,the magnetic flux amplitude error slightly increases.Therefore,considering the end-edge effect,the observer based on the extended Kalman filter can replace the velocity sensor to achieve three-phase LIM control under both unloaded and loaded conditions.