Position Sensorless Control of Brushless Direct Current Motor Based on Improved Sliding Mode Observer

Aiming at the problems of chattering and insufficient accuracy of the rotor position in the traditional sliding mode observer, a sliding mode observer based on the double power reaching law is proposed. By designing a new piecewise function to replace the switching function of the traditional sliding mode observer, By combining the double-power approaching law with the switching function of the new sliding mode observer, the approaching speed of the sliding mode is improved, the chattering problem of the traditional sliding mode observer is weakened, and the observation accuracy of the rotor position is improved. The simulation results show that compared with the traditional method, the designed sliding mode observer can suppress system chattering better, and has better speed estimation accuracy.