The rotor position detection of BLDCM without position sensor is studied. The problem of back EMF cannot be detected under low speed and no speed. The three-stage start method is used for starting.Through the analysis of the structure and operating principle of the BLDCM, the mathematical model of the BLDCM is established.The simulation model is built by Matlab/Simulink. The hardware composition and software design scheme and control strategy of the control system are briefly described. The control system is analyzed. The system can simplify the hardware structure and make the motor control efficient and stable.The Matlab simulation module was built for the modular method.The feasibility of the above control method is verified by experiments, and the sensorless starting of BLDCM in full speed range is realized.

BLDCM, no position sensor, back electromotive force method.