Brushless DC motors (BLDCM) are widely used in aerospace and other control fields due to their advantages of long life, high power density, small size, and large output torque. However, the traditional method of using the sensor to obtain the rotor position signal has the disadvantages of difficulty in manufacturing, susceptibility to interference, and difficulty in working in high and low temperature environments, which greatly limits its wider application. Sensorless control technology can overcome these shortcomings.