关键词: 永磁同步电机, 滑模观测器, 二阶广义积分器, 前馈锁相环

Abstract: In traditional sensorless control systems for permanent magnet synchronous motor ( PMSM) based on sliding mode observers and phase-locked loop ( PLL) ,phase delay and position tracking error occur in the PLL during acceleration and deceleration, which are the main sources of position estimation errors. This paper proposes a sensorless position estimation method based on a second-order generalized integrator ( SOGI) and a feedforward PLL. The mathematical model of the PMSM was established, and a sliding mode observer was designed. The SOGI was introduced to process the back electromotive force signals. Its characteristics ensure that the amplitude and phase of the fundamental component remain
unaffected,while effectively suppressing harmonics and DC components. The speed feedforward was incorporated into the PLL structure,which increases the system order and improves the dynamic response, thereby further reducing estimation errors during acceleration and deceleration. The experimental results show that the proposed method does not require phase compensation and can effectively reduce the position tracking error during dynamic processes.

Key words: permanent magnet synchronous motor, sliding mode observer, second-order generalized integrator, feedforward plase-locked loop