电网不平衡工况下高频链矩阵变换器非线性反步控制策略

高频链矩阵变换器(high-frequency linkmatrix converter,HFLMC)因具有高效率、高功率密度、高可靠性等优势，在V2G、储能、微电网等应用中受到广泛关注。但在三相电网电压不平衡工况下，HFLMC不仅在网侧产生电流畸变，降低电能质量，而且在直流侧产生二倍频波动，降低负载和系统可靠性。为此，文中提出一种兼顾电网平衡和不平衡工况的HFLMC非线性反步控制策略(onlinear backstepping control strategy under unbalanced grid conditions,UBG-BSC)。首先，建立HFLMC数学模型，分析不平衡工况下HFLMC的瞬时功率，推导出两相静止坐标系下的输入电流参考值；然后，基于HFLMC数学模型分别设计α轴和β轴反步控制器，实现对输入电流参考值的快速跟踪控制，并根据李雅普诺夫稳定性理论证明HFLMC闭环系统的稳定性；最后搭建2kW实验样机，结果表明，相比于传统控制策略，采用所提UBG-BSC策略的HFLMC网侧THD降低了1.7%，直流侧二倍频波动减小了76%，输出电流响应速度提升了85%。

Nonlinear Backstepping Control Strategy for High-frequency Link Matrix Converter Under Unbalanced Grid Conditions

High-frequency link matrix converter(HFLMC)is getting much concern due to its high efficiency,compact volume and high reliability in the applications,such as vehicle to grid(V2G),energy storage and microgrid.However,under unbalanced grid voltage conditions,HFLMC not only induces current distortion on the grid side which reduces power quality,but also induces double grid-frequency ripples on the dc side,which reduces load and system reliability.To solve the above problems,this paper proposed a nonlinear backstepping control strategy for HFLMC under unbalanced and balanced grid conditions(UBG-BSC).Firstly,the mathematical model of HFLMC was established,and the instantaneous power under unbalanced conditions was analyzed to derive the current reference value in two-phase stationary frame.Then theαbackstepping controller andβbackstepping controller were designed to track the current reference based on HFLMC mathematical mode.And the stability of HFLMC closed-loop system was proved according to the Lyapunov stability theory.Finally,a 2kW experimental prototype was built.The experimental results show that compared with the traditional PR control strategies,the grid side THD of the proposed UBG-BSC strategy in this paper is reduced by 1.7%,and the ripples on the dc side is reduced by 76%,and the output current response rate is improved by 85%.