Multivariable sliding-mode extremum seeking PI tuning for current control of a PMSM

Abstract

High-performance current control is critical for obtaining smooth output torque in permanent-magnet synchronous motors (PMSMs). To this end, a new proportional-integral (PI) tuning method based on multivariable sliding-mode extremum seeking is proposed in this study and applied for current control of a PMSM. In the proposed method, a sliding-mode extremum seeking optimiser varies the PI gains by minimising a cost function based on the feedback error term. The resulting PI controller can achieve fast and accurate tracking response, high disturbance rejection, and low sensitivity to PMSM parameter variations. The stability of the proposed control strategy is investigated through a Lyapunov analysis and its performance is evaluated through experimental studies. The results indicate that the proposed controller can offer improved performance in terms of accuracy, parametric variations, and load torque disturbances when compared with a conventional PI and a recently proposed PI controller using the gradient-based extremum seeking tuning method.