关键词: 永磁同步电机, 滑模观测器, 流频比启动, 正弦饱和函数

Abstract: The inherent chattering characteristics of sliding mode observer leads to certain errors in the observation of angle and speed, and the observer cannot converge effectively at zero and low speeds. To further optimize the performance of the observer and achieve stationary startup, this thesis replaces the sign function with a sine saturation function, reducing chattering ar zero crossings; and introduces a phase-locked loop replacing differential operations to observe speed, improving observation accuracy; during the starting period, a new closed-loop switching method was designed using a slip frequency ratio strategy, only the angle needs to be processed, reducing the complexity of the switching process. Based on the AIP32F7532, this thesis builds an experimental platform for permanent magnet synchronous motors. Experimental results show that the improved control strategy reduces speed error by 60% and angle error by 56% at medium and high speeds; it starts reliably under loaded conditions, and the switching process is smooth and stable.

Key words: permanent magnet synchronous motor, sliding mode observer,  frequency ratio start, sine saturation function