Robust nonlinear speed control of PM synchronous motor using boundary layer integral sliding control with sliding load torque observer

An improved nonlinear speed control of a permanent magnet synchronous motor (PMSM) is presented. A quasi-linearized and decoupled model including the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode (BLISM) controller to improve the robustness and performance of the nonlinear speed control of a PMSM if designed and compared with the conventional controller. A sliding load torque observer to improve the performance of the control is designed and its performance is compared with the asymptotic load torque observer in the conventional control scheme. By employing the proposed control scheme, both the transient and steady state responses are greatly improved under the parameter variations and speed measurement error.