Current Decoupling Control of Linear Synchronous Motor Based on an Improved Sliding Mode Observer

Abstract

This paper proposes an improved sliding mode observer (ISMO) for the current decoupling control of the linear synchronous motor (LSM) to improve the dynamic performance of the LSM system. The proposed ISMO is based on variable power and exponential terms. By comparing the convergence time of the proposed ISMO and the conventional sliding mode observer (CSMO), we find that the ISMO can achieve a high convergence rate than the CSMO with the appropriate parameter options. Because the ISMO is established based on the extended state equation of the lumped disturbances, which includes the current coupling interferences and parameter variation disturbances, the ISMO-based decoupling control (ISMO-DC) can suppress these two types of disturbances simultaneously. The stability analysis based on the Lyapunov stability theory guarantees the convergence of the proposed ISMO. The experimental results verify the effectiveness of the proposed method in achieving a better decoupling control performance for the LSM system.INDEX TERMS Decoupling control, linear synchronous motor, robustness, sliding mode observer.