Sensorless Control of Permanent Magnet Synchronous Motor Based on Adaptive Sliding Mode Observer

Abstract

In view of the serious high frequency chattering of the traditional sliding mode observer (SMO) and the insufficient accuracy of rotor position and motor speed estimation, an improved adaptive sliding mode observer is proposed to improve the observation accuracy of rotor position and motor speed and suppress the chattering of the system. By designing an appropriate adaptive law, the high frequency harmonics in the back electromotive force are eliminated. Using sigmoid function instead of symbol function as switch function, which improves the approach speed of sliding mode and weakens the high frequency chattering of the traditional SMO. At the same time, the position of the rotor is estimated by the phase-locked loop (PLL), which eliminates the influence of rotor speed. The compensation link of the rotor position angle is omitted, and the rotor position observation accuracy is improved. The simulation results show that the estimation method based on adaptive sliding mode observer improves the observation accuracy of motor speed and rotor position and has good control performance.