具有复数滤波器结构锁相环的并网逆变器对弱电网的适应性研究  

Research on Adaptability of Grid-Connected Inverter with Complex Coefficient-Filter Structure Phase Locked Loop to Weak Grid

作　　者：涂春鸣[1] 高家元 李庆 姜飞[2] 郭祺[1] Tu Chunming;Gao Jiayuan;Li Qing;Jiang Fei;Guo Qi(National Electric Power Conversion and Control Engineering Technology Research Center Hunan University,Changsha 410082 China;School of Electrical and Information Engineering Changsha University of Science and Technology,Changsha 410004 China)

机构地区：[1]国家电能变换与控制工程技术研究中心(湖南大学),长沙410082 [2]长沙理工大学电气与信息工程学院,长沙410004

出　　处：《电工技术学报》2020年第12期2632-2642,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51577055);国家自然科学基金青年基金(51707014);湖南省自然科学基金青年基金(2018JJ3534)资助项目。

摘　　要：针对传统的同步旋转坐标系锁相环结构的逆变器并网系统,结合复数滤波器基波正序电压提取特性,构建具有复数滤波器结构锁相环的逆变器并网系统(CFPLL-GIS)。在此基础上充分考虑锁相环影响,建立CFPLL-GIS的阻抗模型,并通过基于阻抗的稳定性判据分析,说明复数滤波器结构的引入可以提高逆变器并网系统等效输出阻抗在中频段内的相角,能够显著改善逆变器并网系统对弱电网的适应能力;同时结合CFPLL-GIS的结构特点并以逆变器并网系统的环路增益为设计指导,提出一种逆变器并网系统等效输出阻抗重塑控制策略,改善系统的阻抗特性,保证逆变器并网系统具有充足的稳定裕度,进一步拓宽CFPLL-GIS对电网阻抗的适应范围。最后,通过仿真和实验验证了本文理论分析的正确性以及所提控制策略的有效性。According to the traditional synchronous rotating frame PLL(SRF-PLL)gridconnected inverter system,combined with the fundamental positive sequence voltage extraction characteristics of complex coefficient-filter,an grid-connected inverter system with complex coefficient-filter-based PLL(CFPLL-GIS)is constructed.On this basis,considering the influence of PLL,the impedance model of CFPLL-GIS is established.The impedance-based stability criterion analysis shows that the introduction of complex coefficient-filter structure can improve the phase angle of equivalent output impedance of grid-connected inverter system in the middle frequency band,and can significantly improve the adaptability of grid-connected inverter system to weak grid.Meanwhile,taking the loop-gain of the grid-connected inverter system as the design guide,a remodeling control strategy of equivalent output impedance of the grid-connected inverter system is proposed to improve the impedance characteristics of the system,ensuring sufficient stability margin of the grid-connected inverter system and further broadening the adaptive range of the CFPLL-GIS to the grid impedance.Simulation and experimental measurements verify the proposed strategy.

关 键 词：弱电网 复数滤波器 锁相环 并网逆变器 阻抗判据 阻抗重塑 稳定裕度 

分 类 号：TM464[电气工程—电器]