Sliding mode speed control for interior permanent magnet synchronous machine based on variable exponential reaching law

In order to solve such problem as sensitivity to the load torque variations of PI speed controller for interior permanent magnet synchronous machine (IPMSM), and to reduce the overshoot of system speed, a sliding mode controller (SMC) for IPMSM speed control system is proposed in this paper. And the chattering problem of SMC is eliminated by applying the variable exponential reaching law and saturation function. The experimental results demonstrate that the control algorithm makes system speed less overshoot, shows robustness to load torque disturbance, and effectively improves dynamic and static operation performance as well as system reliability.