A novel reaching law sliding mode speed controller design for PMSM

In the vector control system of a permanent magnet synchronous motor (PMSM), a speed controller based on sliding mode control (SMC) is designed for the problems of large d-q axis current ripple and unstable system performance due to the sampling time delay of the speed and current loops caused by the carrier period. Meanwhile, a novel reaching law is also proposed based on the power reaching law, and the speed controller designed according to the reaching law can better reduce the current ripple and chattering, and improve the system performance. The d-q axis current and motor speed waveforms in the motor experiments are analyzed from a microscopic perspective by plotting the phase diagram. Numerical simulations and experiments have demonstrated that the speed stability and response of the system can be improved by this control method compared with the conventional SMC controller.