Analysis and Implementation of Brushless DC Motor Control System without Position Sensor

With the development of the economy and the improvement of people's awareness of energy conservation, high-performance and high-efficiency motors have great development prospects. Brushless DC motors are gradually occupying the market due to their high efficiency, low noise, small size and long life. The brushless DC motor replaces the traditional mechanical commutation with electronic commutation, which greatly improves the operating efficiency. This paper analyzes the operating principle of brushless DC motor and the principle of position sensorless control. With STM32 controller as the core, the speed-regulating control system is designed, the square wave drive control technology is adopted, and the anti-electromotive force zero-crossing detection method is used for phase conversion, so as to realize the position sensorless control. The system adopts PI closed-loop control to ensure stable operation of the system. Taking the three-phase brushless DC motor as an example, the signal output test shows that the system can control the stable operation of the motor well and the motor speed response is fast.