一种分数阶滑模观测器的永磁同步电机无传感器控制策略

Sensorless Control Strategy of PMSM Based on Fractional-Order Sliding Mode Observer

滑模观测器法广泛应用于永磁同步电机无传感器控制中,其具有算法简单、易实现等优点。但是,由于传统滑模观测器中趋近率的开关特性,将会带来系统抖振较大,控制精度低等问题。针对这一系列问题,设计了分数阶滑模观测器,在观测器中,将分数阶微积分理论引入滑模控制律中,设计分数阶趋近率。同时,设计了边界层可变的分段型指数函数,将其代替传统趋近率中的饱和函数,以获得更好的转速和转子位置辨识精度,最终基于Matlab/Simulink环境下进行该控制系统仿真,由仿真结果可知,设计的分数阶滑模观测器能有效降低系统抖振,增加系统控制精度,验证了该方案的可行性和有效性。

The sliding mode observer method is widely used in sensorless control of PMSM.It has the advantages of simple algorithm and easy implementation.However,due to the switching characteristics of the approach rate in the traditional sliding mode observer,it will bring about the large system chattering,low control accuracy and other issues.Aiming at these problems,a fractional-order sliding mode observer is designed.In the observer,the theory of the fractional-order calculus is introduced into the sliding mode control law,and the fractionalorder approach rate is designed.At the same time,a segmented exponential function with a variable boundary layer was designed to replace the saturation function in the traditional approach rate and obtain better speed and rotor position identification accuracy.Finally,the simulation of control system was implemented based on Matlab/Simulink environment.According to the simulation results,the designed fractional sliding mode observer can effectively reduce the system chattering and increase the system control accuracy,which verifies the feasibility and effectiveness of the scheme.