一种无位置传感器无刷直流电机制动换相方法OA

When the brushless DC motor is braking,the back EMF waveform of the motor will be affected because of the change of rotor speed.In the non-position sensor brushless DC motor control,the conventional commutation method of back EMF zero-crossing delay angle of 30 °can not accurately obtain the commutation point,thus affecting the performance of the motor.In this paper,a commutation method of non-position sensor brushless DC motor in braking process based on back EMF slope is proposed.through the analysis of non-conducting phase back EMF slope,the position signal function based on back EMF slope is constructed.and the corresponding control strategy is proposed.The commutation method does not rely on the back EMF zero crossing detection,and can accurately find the commutation point under the condition of large deceleration of the motor,and control the motor to brake well.The experimental results verify the correctness and feasibility of the method proposed in this paper.