Sensorless control of PMSM based on IF start and sliding mode observer

Abstract This paper proposes a sensorless control method for permanent magnet synchronous motors (PMSMs) that combines an I/F (current-frequency) startup strategy with a sliding mode observer (SMO). The method achieves stable motor startup using I/F control and provides effective torque through a power angle self-adaptive mechanism. A sliding mode observer is employed for precise estimation of rotor position and speed, eliminating the need for mechanical position sensors. Based on the mathematical modeling of PMSMs, a sliding mode controller and state observer are designed, and the proposed method is verified through simulations in Simulink. Simulation results demonstrate that this strategy delivers good dynamic response and system robustness during startup, load disturbance, and sudden speed changes, showcasing strong potential for practical engineering applications.