Adaptive switching gain sliding mode control for speed regulation in PMSMs

Abstract

To suppress uncertainties caused by parametric variations or disturbances, an adaptive switching gain (ASG)is proposed for integral sliding mode control (ISMC) to regulate speed in permanent magnet synchronous motors(PMSMs). According to system uncertainties, the ASG is designed to adjust the switching gain to suppress the chattering.The adaptive law is a positive value resulting in an increment of the switching gain when the tracking trajectory is outsidethe boundary layer. Conversely, it is negative with a decrement of the gain. Further, it improves a convergent rate bythe function of the reciprocal of the tracking error when the trajectory enters the sliding phase. ISMC with the ASG isapplied to a PMSM experiment with the result that this method can effectively suppress high frequency chattering andshows excellent steady state performance of the current loop and speed in a servo system.