Abstract: This paper introduces a sensorless control method for surface-mounted permanent magnet synchronous motors (PMSMs) based on pulsating high-frequency voltage signal injection. Utilizing the magnetic saturation effect of the PMSM, a pulsating high-frequency voltage signal is injected into a coordinate system rotating at the same speed as the rotor. The extracted current is then subjected to coordinate transformation and demodulation to obtain rotor position information, thus realizing a sensorless control strategy. Simulation results demonstrate the correctness of the proposed method . Keywords: Pulsating high-frequency voltage signal injection; Surface-mounted permanent magnet synchronous motor; Magnetic saturation effect; Sensorless control. Permanent magnet synchronous motors (PMSMs) are widely used in scientific and educational instruments, medical devices, and robotics due to their compact structure, good stability, and high power density. To obtain superior dynamic and static speed regulation performance, both vector control and direct torque control require mechanical sensors on the motor shaft to obtain real-time rotor speed and position information. However, these sensors increase the manufacturing cost of the motor, alter its structure, introduce electromagnetic noise, and reduce its reliability. Furthermore, in certain harsh environments, it is impossible to install sensors. Therefore, how to achieve sensorless control of PMSMs has become a hot topic in the field of electric drives. Currently, commonly used methods for speed and position estimation in sensorless control technology include direct calculation, model reference adaptive method, Kalman filter method, sliding mode observer method, etc. However, these methods all have some insurmountable drawbacks, such as over-reliance on motor parameters, inability to determine the initial rotor position, large estimation errors at low speeds, excessive computational load, and slow dynamic response. For details, please click: Permanent Magnet Synchronous Motor Control Method Based on Signal Injection