基于改进全阶滑模观测器变频空调电动机转速辨识研究

Research on motor speed identification of air conditioning systems based on improved full-order sliding-mode observer

为了提高空调电动机转速辨识精度,基于全阶滑模观测器(SMO)展开研究。通过增加反电动势方程,构建了全阶滑模观测器状态方程,去除了传统观测器中的低通滤波器,避免了滤波器带来的相位误差问题,进而提高了系统的鲁棒性和动态观测性。优化了滑模面切换函数,以削弱系统抖振现象。采用三阶正交锁相环,对观测器输出的反电动势进行相位追踪。通过实验完成了空载启动、转速突变及低速实验,验证了所采用算法的准确性和鲁棒性。频率误差控制在0.2 Hz以内,有效提高了观测器的估算精度和抗干扰能力,保证了空调系统的高效、恒温及除湿性能。

To improve the accuracy of motor speed identification for the air conditioning system,represents researches based on the improved full-order sliding-mode observer(SMO).Establishes a state equation for the full-order sliding-mode observer based on the back-electromotive force equation.Removes the low-pass filter in the traditional observer to avoid the phase error caused by the filter,and thus improves the robustness and dynamic observability of the system.Optimizes the switching function of the sliding-mode surface to reduce buffeting.Uses the third order orthogonal phase-locked loop to track the back-electromotive force output by the observer.The accuracy and robustness of the algorithm is verified by conducting the no-load start,sudden speed change and low speed experiments.By keeping the frequency error within 0.2 Hz,it can effectively improve the estimation accuracy and anti-interference ability of the observer,and consequently ensure the high efficiency,temperature constancy and excellent dehumidification performance of the air conditioning system.