基于改进型二阶广义积分器的同步信号检测

为了满足三相电压在不对称、直流分量及谐波畸变等情况下并网变换器的控制需求,需要准确地检测出电压信号的正序分量、幅值和基波频率。基于双二阶广义积分器锁频环的方法可实现电压在不对称和畸变下同步信号的提取。但当电压信号含有直流分量和多次谐波时,基本的SOGI结构滤波效果不理想,追踪的波形波动比较大,并降低了追踪速度。文中介绍一种改进的SOGI结构,该结构在SOGI的基础上增加求差节点和自适应滤波器,并保留SOGI-FLL的优势。电压的幅值和基波频率能准确快速被检测出来,很好的减小频率跳变后的波动、滤除谐波和消除直流分量。MATLAB仿真结果表明,其改进方法在电压信号不对称、直流分量及多次谐波存在条件下准确地检测出正序分量和基波频率。

Synchronous signal detection based on improved second-order generalized integrator

In order to meet the control requirements of the grid connected converter under the condition of asymmetry,DC component and harmonic. the positive sequence component,amplitude and fundamental frequency of the voltage signal should be detected accurately. The method based on dual second order generalized integrator FLL can extract synchronous signal under the voltage asymmetry and distortion. However,when the voltage signal contains DC component and multiple harmonics,the filtering effect of basic SOGI structure is not ideal,the waveform tracking is relatively large,and the tracking speed is reduced. In this paper,improved SOGI structure is proposed,which increase the differential node and the adaptive filter based on SOGI,and retain the advantages of SOGI-FLL. The amplitude and frequency of the voltage can be detected accurately and quickly,while it can well reduce frequency hopping fluctuation,harmonic filter and eliminate the DC component. MATLAB simulation results show that the improved method can accurately detect the positive sequence component and frequency of the fundamental wave under the condition of voltage signal asymmetry,DC component and multiple harmonics.