Position Sensorless Control of Brushless DC Motor

According to the chattering problem in the traditional sliding mode observer of the position sensorless control of brushless DC motor, a novel quasi sliding mode observer for rotor position estimation was proposed, which took the error between the actual and estimated currents as sliding surface and tracked the actual rotor position according to the mathematical relationship of back EMF and speed of the motor. Then the sensorless control system of the brushless DC motor based on the novel sliding mode observer was designed. Simulation results showed that the novel sliding mode control method could improve the rotor position estimation accuracy and effectively suppress the chattering problem to enhance the robustness of system.