A synchronizing signal detection technique for grid voltage based on new CDSOGI-PLL

一种新型级联CDSOGI-PLL的电网电压同步信号检测技术

School of Automation, Northwestern Polytechnical University, Xi'an 710072, China

Received: 13 October 2022

Abstract

When the grid voltage contains many harmonics, the filtering effect of the phase-locked loop based on dual second-order generalized integrator (DSOGI-PLL) is not ideal, and the frequency of synchronous signal extracted through the DSOGI-PLL fluctuates. A novel phase-locked loop structure based on cascade second order generalized integrator (CDSOGI-PLL) is proposed. The structure utilizes the cascaded SOGI module to simultaneously weaken the harmonics and inter-harmonics that exist in the grid voltage, thus reducing the influence of harmonics on the PLL and accurately extracting the grid voltage's synchronous signal. Matlab simulation and experimental results show that the signal detection technique proposed in the paper can effectively extract the fundamental positive sequence component, frequency and phase when the grid voltage is unbalanced and has many harmonics.

摘要

基于双二阶广义积分器的锁相环DSOGI-PLL在电网电压含有大量低次谐波时, 其滤波效果不理想, 锁相环提取的同步信号频率出现波动。在DSOGI-PLL的基础上, 提出一种新型的级联锁相环结构CDSOGI-PLL(cascade second-order generalized integrator PLL)。该结构利用级联的SOGI模块同时削弱电网电压中的各次谐波和间谐波, 从而减少谐波对锁相环的影响, 准确地提取电网电压同步信号。Matlab仿真和实验结果均表明, 文中提出的新型CDSOGI-PLL在电网电压不对称和含有大量低次谐波时能有效、准确地提取基波的正序分量、频率和相位。