弱电网下基于一阶复矢量滤波器的锁相环补偿控制策略及鲁棒性分析  

Compensation control strategy and robustness analysis of PLL based on first order complex vector filter in weak grid

作　　者：杨明[1] 胡梦圆 刘晋宏 杨杰 赵月圆 YANG Ming;HU Mengyuan;LIU Jinhong;YANG Jie;ZHAO Yueyuan(School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454003,China;School of Automation,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]河南理工大学电气工程与自动化学院,河南焦作454003 [2]南京理工大学自动化学院,江苏南京210094

出　　处：《电机与控制学报》2023年第10期160-170,共11页Electric Machines and Control

基　　金：国家自然科学基金(U1804143);河南理工大学骨干教师资助计划(2020XQG-18)。

摘　　要：LCL型并网逆变器的跟网型控制中,一般采用锁相环获取公共耦合点电压相位信息。在弱电网条件下,并网逆变器控制系统存在电网阻抗与传统同步旋转坐标系锁相环的交互作用,导致其出现鲁棒性较差甚至难以稳定运行的问题。首先利用阻抗模型分析并网逆变器在弱电网下失稳机理,揭示了锁相环和电压前馈将在输出阻抗中引入一个附加项,并得出该附加项将对系统鲁棒性造成影响,进而提出一种在锁相环和电网电压前馈通道前串联新型一阶复矢量滤波器的补偿控制策略。分析表明:该控制策略减小了电网阻抗、锁相环带宽等扰动量对逆变器等效输出阻抗的影响,在电网阻抗宽范围变化时仍可使系统具有足够的稳定裕度,提高了并网逆变器的鲁棒性。最后,通过仿真分析和实验验证了所提控制策略可有效提高系统对弱电网的适应性,且具有良好的动静态性能。In grid-following control of LCL-type inverters,a phase-locked loop is generally adopted to acquire phase information of the voltage at the point of common coupling.Addressing the interaction between grid impedance and the conventional synchronous rotating coordinate system phase-locked loop under weak grid,which leads to poorer robustness and even unstable operation of the grid-connected inverter control system,this study firstly utilizes an impedance model to analyze the instability mechanism of grid-connected inverters under weak grid conditions.It reveals that the phase-locked loop and voltage feedforward will introduce an additional term in the output impedance,concluding that this additional term will impact the system’s robustness.Subsequently,a compensatory control strategy is proposed,involving the series connection of a new first-order complex vector filter in the phase-locked loop and grid voltage feedforward channels.Analyses indicate that this control strategy mitigates the influence of disturbances such as grid impedance and phase-locked loop bandwidth on the equivalent output impedance of the inverter,maintaining sufficient stability margin for the system under a wide range of grid impedance variations and enhancing the robustness of the grid-connected inverter.Finally,simulation analyses and experiments validate that the proposed control strategy effectively improves the system’s adaptability to weak grids and possesses excellent dynamic and static performance.

关 键 词：并网逆变器 锁相环 弱电网 等效阻抗模型 新型一阶复矢量滤波器 

分 类 号：TM464[电气工程—电器]