基于滤波反步法的光伏并网系统设计与仿真

Photovoltaic grid connected system design and simulation based on filtering backstepping

光伏并网系统采用LCL型滤波时,系统的数学模型阶数较高,采用常规反步法设计会面临着对多个虚拟控制量逐步求导的问题,这样不仅会使计算过程繁琐,而且求导会加大测量噪声的影响,导致电流误差和输出电流的谐波增大。为解决上述问题,文章设计了一种基于滤波反步法的光伏并网系统,该方法结合李雅普诺夫稳定性理论并通过滤波器实现求导过程,显著减小了测量噪声的影响。理论分析和仿真结果表明:该方法的电流误差和输出电流的总谐波失真度(THD)小,实现了较好的并网同步效果,有较好的实用价值。

When the LCL filter is used in the photovoltaic （PV） grid-connected system, the mathematical model of the system has a high order, and the design of the conventional backstepping method will bring about the problem of the multiple virtual control volumes＇ gradual derivation, which will not only result in complicated calculation, but also increase the influence of the measurement noise on the gradual derivation and lead to the increase in the current error and harmonies of the output current. In order to solve these problems, the paper designed a photovoltaic grid-connect- ed system based on the filtering backstepping method. This method, which was combined with the Lyapunov stability theory and implemented the derivation process through a filter, considerably reduced the influence of the measurement noise. The theoretical analysis and simulation results showed that the current error and the total harmonic distortion （THD） of the output current of the method were small, and this method could achieve good grid synchronization per-formance and had good practical values.