Adaptive backstepping PI sliding-mode control for interior permanent magnet synchronous motor drive systems

An adaptive backstepping PI sliding-mode control is proposed for speed control of the drive of an interior permanent magnet synchronous motor (IPMSM) subjected to load disturbances. First, a nonlinear model with uncertainties is derived for the IPMSM, and then an adaptive backstepping sliding-mode controller incorporating a linear load torque estimator is designed. Next, the parametric uncertainties of the model are handled with adaptive laws in the design of the controller. To attenuate the chattering problem without sacrificing the feature of the sliding-mode control, an adaptive Pi-saturation function is used to approximate the signum function within the boundary layer. Asymptotic stability of the proposed control method is proven by Lyapunov stability theory and Barbalat's lemma. A digital signal processor, TMS320LF2407, is adopted to implement the proposed control scheme. The experimental results show that the proposed system can effectively reduce the chattering phenomenon and has fast transient response, good load disturbance rejection response, and good tracking response.