Research on Sliding Mode Observer of Permanent Magnet Synchronous Motor Based on Novel Phase-Locked Loop

针对传统滑模观测器(SMO)在电机转子位置估计中存在高频抖动、稳态误差大、动态性能差等问题，文章提出了一种改进型滑模观测器(改进SMO)。该方法采用饱和正弦函数代替传统符号函数，有效抑制了高频抖动；同时引入改进的锁相环结构，替代传统锁相环，实现了电机转速从正转到反转的有效观测，并显著提高了转速与转子位置的跟踪精度。仿真结果表明，与传统方法相比，改进SMO的位置估计稳态误差降低超过80%。在给定转速由1000 r/min突变至1500 r/min及负载突加至5 N的动态工况下，改进SMO表现出更快的响应速度，位置估计误差始终控制在±0.02 rad以内，显著优于传统方法的±0.1 rad。此外，改进SMO具备更强的鲁棒性和抗扰能力，更适用于实际电机驱动系统的转子位置估计，具有广泛的工程应用前景。This paper proposes an improved sliding mode observer (SMO) to combat high-frequency chattering, large steady-state errors, and poor dynamic performance in traditional SMOs for rotor position estimation in electric motors. This method replaces the sign function with a saturated sine function, thereby effectively suppressing high-frequency chattering. Additionally, an improved phase-locked loop (PLL) structure is introduced to replace the conventional PLL, enabling accurate observation of motor speed transitions from forward to reverse rotation and significantly enhancing the speed and rotor position tracking accuracy. Simulation results show that, compared with traditional methods, the improved SMO reduces the steady-state error of position estimation by more than 80%. Under dynamic conditions, where the given speed changes from 1,000 r/min to 1,500 r/min and a sudden load of 5 N is applied, the improved SMO exhibits a faster response speed, with position estimation errors consistently maintained within ±0.02 rad, significantly outperforming the ±0.1 rad error of traditional methods. Moreover, the improved SMO demonstrates superior robustness and disturbance rejection, making it more suitable for rotor position estimation in practical motor drive systems with broad engineering application prospects.