Design and implementation of a nonlinear speed controller with adaptive backstepping sliding mode technique for an IPMSM drive system

This paper proposes a nonlinear speed controller for an interior permanent magnet synchronous motor (IPMSM) drive system. First, the input-output feedback linearization control is used to derive a linearized model including load torque variations and lumped parameter uncertainties. In order to reduce the influence of load torque disturbances on the linearized model, an external load torque estimator is employed for the load torque estimation. To overcome the lumped parameter uncertainties, an adaptive backstepping approach with adaptation mechanisms is derived. After that, combining with a sliding mode control technique is used to improve the robustness of the speed control system. By using Lyapunov stability theory and Barbalat´s lemma, the proposed control scheme is shown to be globally asymptotically stable. A digital signal processor, TMS320LF2407, is used to implement the proposed control scheme. The experimental results show that the proposed system has fast transient responses, good load disturbance rejection responses, and good tracking responses.