弱电网下基于比例权重的控制环参数自适应调整并网逆变器稳定性提升方法  

Stability Improvement Method of Grid-Connected Inverter Based on Proportional Weight Control Loop Parameters Adaptive Adjustment under Weak Grid

作　　者：高家元 黄帅[1] 姜飞[1] 涂春鸣[2] 肖凡[2] Gao Jiayuan;Huang Shuai;Jiang Fei;Tu Chunming;Xiao Fan(School of Electrical and Information Engineering Changsha University of Science and Technology,Changsha 410004,China;National Electric Power Conversion and Control Engineering Technology Research Center Hunan University,Changsha 410082,China)

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

出　　处：《电工技术学报》2024年第24期7846-7859,共14页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点基金项目(52130704);国家自然科学基金面上项目(52077072)资助。

摘　　要：针对弱电网下并网逆变器(GCI)与电网阻抗交互易失稳的问题,以dq域下控制的GCI为例,构建考虑等效电流源稳定性的GCI的单输入单输出(SISO)阻抗模型,该模型将等效电流源中控制器参数变换到GCI的等效输出阻抗模型中,并将锁相环(PLL)引发的阻抗回路折算到电网侧,实现等效电流源与控制器参数解耦,为控制环参数自适应调整控制策略下GCI的稳定性分析奠定了模型基础。在此基础上,提出一种基于比例权重的控制环参数自适应调整控制方法,并基于所构建阻抗模型实现比例权重系数的分析与设计,该自适应控制方法能够保证GCI在弱电网范围内具有30°以上的充足稳定裕度,促使GCI具有良好的稳态与动态性能。最后,通过仿真和实验验证了该文理论分析的正确性以及所提控制策略的有效性。The interaction between grid-connected inverter(GCI)and grid impedance under a weak grid easily induces system instability,threatening the safe and reliable operation of new energy power generation.At present,the method for optimizing and adjusting the parameters of the control loop is widely used to improve the stability of the GCI under a weak grid because of its simple operation and non-auxiliary control loop.The equivalent current source is defaulted to stable when using the impedance model.However,the actual situation is likely to induce instability in the equivalent current source,which leads to the failure of the impedance analysis method and restricts wide applications.Therefore,the multiple-input multiple-output impedance model of GCI controlled in the dq domain is converted into the impedance form of single-input single-output by equivalent transformation.Then,through impedance transfer and remodeling,the controller parameters in the equivalent current source are transformed into the equivalent output impedance model of GCI,and the impedance loop caused by the phase-locked loop(PLL)is converted to the grid side to characterize the negative impact of the PLL.The impedance modeling method realizes the decoupling between the equivalent current source and the control loop parameters.Under the control loop parameter adjustment,the stability of the equivalent current source can be ensured,and the problem for the stability analysis of GCI is solved.A stability improvement method of control-loop parameter adaptive adjustment based on proportional weight is proposed.The proportional weight coefficient is analyzed and designed,which ensures that the GCI has a sufficient stability margin of more than 30°in the weak grid range.Meanwhile,the stability analysis and simulation verification are carried out with a short circuit ratio of 2 and 20%detection error.The results show that the adaptive control method can promote the GCI to maintain good steady-state and dynamic performance despite grid impedance detection err

关 键 词：弱电网 并网逆变器 控制器参数解耦 自适应控制 稳定裕度 

分 类 号：TM464[电气工程—电器]