南方电网技术2025，Vol.19Issue(5)：1-15,15.DOI:10.13648/j.cnki.issn1674-0629.2025.05.001
不对称工况下并网换流器小信号精准建模及其稳定性量化分析
Accurate Modeling and Stability Quantitative Analysis of Small Signal for Grid-Connected Converter Under Asymmetric Operating Conditions
摘要
Abstract
The impedance analysis method is common for understanding the small signal stability of new energy grid-connected systems.In impedance modeling works,the three-phase symmetry of the grid side AC system is assumed,and the port impedance characteristics of the converter can be described using a second-order matrix.However,under asymmetric conditions,the converter exhibits more complex frequency coupling characteristics,and the model is no longer applicable.This paper firstly considers the sideband effect of a pulse width modulation(PWM)modulation and the frequency aliasing effect of sampling link,phase-locked loop dynamics,DC voltage control,positive and negative sequence current inner loop control,and other influencing factors,and establishes a small signal model of grid-connected converter suitable for three-phase asymmetric conditions.Then,a method for equivalenting a multi-input-multi-output(MIMO)system to a single-input-single-output(SISO)system under asymmetric operating conditions is proposed,and the correctness of the theoretical analysis is verified through PSCAD/EMTDC.Furthermore,the asymmetry of the grid-connected converter system is defined and the influence of control parameters on the system asymmetry is analyzed.Finally,the stability of grid-tied systems under asymmetry operation condition is analyzed based on the maximum peak Nyquist criterion.关键词
并网换流器/脉冲宽度调制(PWM)/不对称工况/单输入单输出等效/最大峰值准则Key words
grid-connected converter/pulse width modulation(PWM)/asymmetric operation condition/SISO equivalence/maximum peak criteria分类
动力与电气工程引用本文复制引用
叶柏贤,王学梅,冯俊杰,汪娟娟,王泽昊,李芷晴..不对称工况下并网换流器小信号精准建模及其稳定性量化分析[J].南方电网技术,2025,19(5):1-15,15.基金项目
国家自然科学基金资助项目(52277102).Supported by the National Natural Science Foundation of China(52277102). （52277102）
