Abstract:

The brushless dc motor control system with the hall sensor increases the size of the whole system,limiting its application in some special fields.A method of position sensor-less is proposed by detecting the location of the counter electromotive force,which determines the rotor position to obtain the same signal of rotor position.The system model is built in the Matlab/Simulink.The PI control regulation is applied to speed loop while hysteresis control regulation is applied to current loop,and the rotor position signal of counter electromotive force is delivered to the current loop.The simulation results show that the method proposed has good dynamic and static characteristics with the electromagnetic torque closely following the given signal,which verifies its effectiveness.

Key words: BLDCM;position sensor-less method;back EMF;system simulation