Research on permanent magnet synchronous motor control based on an improved high-order sliding mode observer

Abstract This paper proposes an improved high-order sliding mode observer (HOSMO) based on an extended back-EMF model for PMSM control systems, effectively addressing the inherent chattering issues of conventional SMO and overcoming their switching-related performance limitations. By replacing the conventional sign function with a soft-sign function, the proposed observer synergistically integrates the advantages of both high-order sliding mode techniques and the modified sign function. This innovation not only eliminates the need for a low-pass filter but also circumvents the phase compensation step, enabling smooth estimation of the EMF. Extensive simulations conducted on the MATLAB/Simulink platform validate the effectiveness and superiority of the proposed method.