基于谐波传递函数矩阵的单相并网系统建模研究  

Research on the Modeling of Single-phase Grid-connected System Based on the Harmonic Transfer Function Matrix

作　　者：钱强 张犁 谢少军[2] 许津铭[2] QIAN Qiang;ZHANG Li;XIE Shaojun;XU Jinming(College of Energy and Electrical Engineering,Hohai University,Nanjing 211106,Jiangsu Province,China;College of Automation,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,Jiangsu Province,China)

机构地区：[1]河海大学能源与电气学院,江苏省南京市211106 [2]南京航空航天大学自动化学院,江苏省南京市211106

出　　处：《中国电机工程学报》2021年第12期4132-4143,共12页Proceedings of the CSEE

基　　金：江苏省青年基金项目(BK20200510);国家自然科学基金项目(51877104);中央高校基本科研业务费(B200201022)。

摘　　要：弱电网下,电压源型并网逆变器锁相控制环节引入的频率耦合作用会恶化并网系统稳定性,传统基于阻抗的数学模型尚不能准确反映弱电网下级联系统在低频段的谐振特性及稳定性。文中针对单相并网系统无穷、链式的频率耦合特点,建立考虑偶次频率耦合的多输入多输出谐波传递函数矩阵数学模型,据此提出具有明确物理意义的单输入单输出阻抗模型,讨论该阻抗模型的简化降阶方法及其在基波频率处阻抗特性,指出仅考虑正负两倍基波频率搬移的频率耦合作用已较好地保证了模型的准确度。进一步,基于所提阻抗模型研究电网阻抗及几种常见正交信号发生器对单相并网系统稳定性的影响,表明电网阻抗会影响逆变器输出阻抗,锁相环环路中等效滤波环节会改善弱电网下系统的稳定性。仿真和实验测量验证了所提单相并网系统阻抗模型正确性及其应用于弱电网下并网系统谐波稳定性分析的有效性。In weak grid, the frequency coupling effect(FCE) introduced by the phase-locked loop(PLL) of the voltage-source grid-connected inverter will jeopardize the system stability. However, the traditional impedance model is inaccurate to identify the low-frequency harmonic resonance and stability of the inverter-grid cascaded system. To capture the infinite and the chained FCE of single-phase system, this paper established the multi-input-multi-output harmonictransfer-function-based matrix model with the consideration of the even-frequency couplings, which is further developed as the proposed single-input-single-output impedance model with clear physical meaning. Based on the discussion of the impedance behavior around the fundamental frequency and the method of the model simplification, the model accuracy is ensured with only taking FCE induced by the positive and the negative twice-fundamental-frequency-shift into account. Moreover, the influence of the grid impedance Zg and several orthogonal signal generators on the system stability was studied, which indicates that the inverter output impedance is influenced by Zg, and the equivalent filter block of PLL enhances the stability. The simulation and experiment verified the correctness of the elaborated model and the effectiveness of its application in analyzing the harmonic stability of the grid-connected system in weak grid.

关 键 词：单相逆变器 谐波传递函数 锁相环 广义奈氏稳定判据 频率耦合效应 

分 类 号：TM46[电气工程—电器]