基于离散复变量自适应滤波器的三相电网同步算法

摘要

电网同步算法是并网变换器控制算法的重要组成部分,其对于并网变流器控制性能的提高较为重要.文中针对电网同步算法,首先从离散Luenberger观测器设计的角度,设计了一种离散复变量滤波器,用于提取序分量,并针对谐波应用,建立了基于多重复变量滤波器结构的谐波序分量观测器.其次,分析了输入电压频率与所提序分量观测器频率参数不一致时频率误差的传递过程,进而设计了输入电压频率观测方程,从而使得所提序分量观测器能够自适应于电网频率的变化.建立了线性化的频率误差近似动态模型,以便于频率观测增益的选取.最后,采用仿真与实验来验证所提电网同步算法的正确性与有效性,结果表明该算法能够改善电网频率观测动态性能,缩短了频率观测时间,应用实施简单有效,计算量小.%As an important issue of the control algorithm for grid-connected inverters,the grid synchronization algorithm is critical to improve the control performance of grid-connected inverters.According to the design of the discrete Luenberger observer,a discrete complex-variable filter is designed to extract the sequence component.Moreover,regarding to the application of harmonics,a harmonic sequence component observer based on the structure of a multiple complex-variable filter is developed.The transfer process of the frequency error is analyzed when the input voltage frequency is different from the frequency parameter of the sequence component observer.Then the observation equation of input voltage frequency is designed,which enables the proposed sequence component observer to adapt to the change of grid frequency.In addition,an approximately linearized dynamic model is developed to facilitate the gain design of the frequency observation.Finally,simulations and experiments are carried out to verify the correctness and effectiveness of the proposed grid synchronization algorithm The results show that the proposed algorithm is able to improve the dynamic performance of grid frequency observation while reducing the frequency observation time,and the application implementation is simple and effective with a small amount of calculation.