LCL型逆变器接入弱电网下的谐振分析及抑制方法研究  

Analysis of resonant characteristics and resonance suppression strategy of weak grid with LCL-type inverter

作　　者：王振浩[1] 李丹[1] 贺微 王恺笛 WANG Zhen-hao;LI Dan;HE Wei;WANG Kai-di(School of Electrical Engineering,Northeast Electric Power University,Jilin 132012,China;State Grid Jilin Power Supply Company,Jilin 132001,China;State Grid Dandong Power Supply Company,Dandong 118000,China)

机构地区：[1]东北电力大学电气工程学院,吉林省吉林市132012 [2]国网吉林供电公司,吉林省吉林市132001 [3]国网丹东供电公司,辽宁丹东118000

出　　处：《电工电能新技术》2018年第6期34-42,共9页Advanced Technology of Electrical Engineering and Energy

基　　金：国家自然科学基金项目(51377016)

摘　　要：光伏逆变器并联接入弱电网时,会与时变的电网阻抗产生交互耦合,影响系统稳定性,甚至引发谐波谐振问题。针对此问题,首先,本文建立了LCL型光伏逆变器并联系统的等效电路模型,利用阻抗分析法对弱电网条件下光伏逆变器并网系统的稳定性条件进行了分析,得出逆变器输出阻抗与电网阻抗在谐振频率处具有一定的相角裕度才能使系统稳定运行的结论;其次,提出一种电网电压前馈附加相位超前补偿的控制策略,该策略能够适应不同电网阻抗的接入条件,使系统在谐振频率处具有一定的相角裕度,避免谐振的发生;最后,通过仿真和实验验证了所提出的谐振抑制策略的有效性。When the PV inverter is connected to the weak grid, it will couple with the time-varying grid impedance to affect the stability of the system and even lead to harmonic resonance problem. Firstly, the equivalent circuit model of LCL-type PV inverter parallel system is established. The stability condition of the grid-connected PV in- verier system under weak grid condition is analyzed by impedance analysis method. It is concluded that the output impedance of the inverter and the grid impedance have a certain phase margin at the crossover frequency to make the system operation stable. Secondly, this paper presents a power supply voltage proportional feed-forward additional phase advance compensation control strategy, which can adapt to dirt）rent grid impedance access conditions, so that the system at the resonant frequency with a certain phase angle margin can avoid the occurrence of reso- nance. Finally, the effectiveness of the proposed resonance suppression strategy is verified by simulation and experiment.

关 键 词：并网逆变器 电网电压前馈 相位超前补偿 电网阻抗 

分 类 号：TM46[电气工程—电器]