Rotor position detection of permanent magnet synchronous motor using pulsating high-frequency voltage injection method

Modern industrial automation systems are increasingly incorporating PMSMs, which drives the demand for improved control performance. Traditional control methods relying on position sensors can no longer meet requirements in terms of cost and reliability, making sensorless control a critical research focus. This paper addresses the challenge of weak back electromotive force (EMF) in PMSMs under zero-and low-speed conditions, which renders traditional methods such as sliding mode observers ineffective. The study thoroughly investigates the principles and applications of the pulsating high-frequency voltage injection method. Furthermore, a complete sensorless field-oriented control system diagram for PMSM was developed on the MATLAB/Simulink platform to analyze the effectiveness of the pulsating high-frequency voltage injection method in obtaining rotor position under various starting speed conditions. Simulation verification confirms the proposed approach achieves superior rotor position estimation accuracy in PMSM FOC systems operating at low speeds.