三相Z源逆变器的最优滑模预见重复控制

Optimal sliding mode preview repetitive control of three-phase Z-source inverter

针对微网逆变器带不平衡和非线性负载时三相逆变器输出电压电流谐波大的问题,提出一种最优滑模预见重复控制的方法,实现对不平衡负载和非线性负载等非正常工况的快速响应和参考电压的高精度跟踪。首先,在前馈补偿环节引入预见控制器,并利用差分算子,设计包含目标值信号和滞后环节反馈的扩大状态误差系统,将逆变器的控制问题转化为线性离散系统的调节问题;进一步,利用Lyapunov方法和线性矩阵不等式及最优控制器的设计方法,得到包含滑模控制、状态反馈、重复控制、和预见补偿的最优滑模预见重复控制器。实验结果表明,最优滑模预见重复控制带线性负载时电压波形畸变率从3.12%减少到0.78%,响应时间从10 ms减小为5 ms;其带非线性负载时电压波形畸变率从6.72%减少到0.92%,验证了所提方法的有效性。

To solve the problem of large harmonics of output voltage and current of three-phase inverters with unbalanced and non-linear loads,an optimal sliding mode preview repetitive control strategy is proposed to achieve fast response to abnormal conditions such as unbalanced loads and non-linear loads and high precision tracking of reference voltage.Firstly,a preview controller is introduced in the feed-forward compensation link,and an extended state error system including target signal and feedback from lagging link is designed by using difference operator,which converts the control problem of the inverter into the regulation problem of linear discrete system.Furthermore,by using Lyapunov method,linear matrix inequality and design method of optimal controller,an optimal sliding mode preview repetitive controller including sliding mode control,state feedback,repetitive control and preview compensation is obtained.The experimental results show that the distortion rate of voltage waveform decreases from 3.12%to 0.78%and the response time decreases from 10 ms to 5 ms when the optimal sliding mode preview repetitive control with linear load.The distortion rate of voltage waveform with non-linear load is reduced from 6.72%to 0.92%,which verifies the effectiveness of the proposed method.