滑模观测器在获得较强鲁棒性的同时也具有高频抖振的内在不足,且其抖振会随着滑模增益的增大而加剧。低通滤波器在消除高频抖振的同时,也造成基频观测信号的延迟,进而影响到转子位置观测精度。为此,通常需要对低通滤波器的延迟角度进行补偿,而常规直接计算补偿方案需要用到转速信号,且对转速观测精度较为敏感。此处设计了一种基于双低通滤波器的等效控制反馈滑模观测器方案,一方面通过等效控制信号的反馈降低了所需滑模增益,另一方面通过双低通滤波器对等效控制信号的延迟进行了角度补偿,从而获得了较为准确的转子位置观测。实验结果验证了所设计的无速度传感器系统具有较好的稳态和动态性能。
Along with the high robustness of sliding mode observer,high frequency chatting is one of its inherit drawbacks,and the chatting is more drastic with higher sliding gain.To eliminate the chatting and get the equivalent control used for position calculation,low-pass filter is usually adopted.However,the inevitable delay caused by low-pass filter will hinder the observing accuracy.So,compensation is usually needed.The effect of the usually adopted straight compensation is sensible to the accuracy of speed observation,since speed appears in the compensation calculation.A dual low-pass filters based equivalent control feedback sliding mode observer is designed.In the design,the needed sliding-mode gain is reduced by the proper feedback gain,and the delay is compensated by the designed dual lowpass filters.Therefore,the accuracy of the rotor position is improved.The stable and dynamic performance of the designed speed sensorless control strategy is validated with experiments.