Current decoupling control of linear synchronous motor based on improved extended state observer

Abstract

Linear synchronous motors, with advantages such as high thrust density, fast speed, and strong dynamic response capabilities, are widely used in industrial automation, aerospace, military, transportation, and other fields. The use of vector control in linear synchronous motors can achieve static decoupling of current, but the dynamic coupling relationship still exists. As the speed increases, the impact of dynamic coupling becomes increasingly severe, leading to a decrease in the dynamic performance of the system. Traditional current decoupling control methods, such as current feedback decoupling control and current deviation decoupling control, are sensitive to motor parameters and cannot solve the current decoupling problem caused by changes in inductance parameters during motor operation. Therefore, this paper proposes a current decoupling control strategy based on an improved extended state observer (ESO). By observing the coupling term using the improved ESO and combining it with feedforward control for corresponding compensation, current decoupling control is achieved without relying on accurate inductance parameters, thereby reducing the sensitivity of the strategy to parameters. Furthermore, the stability of the improved ESO was demonstrated using Lyapunov stability theory in the paper. Simulation and experiments have verified that the current decoupling control strategy based on the improved ESO can effectively reduce the dynamic coupling in vector control, enhance the control performance, and significantly improve the system’s robustness.