弱电网下提升并网逆变器无源性的网侧有源阻尼策略  

The Grid-Side Active Damping Strategy for Enhancing the Passivity of the Grid-Connected Inverter in Weak Grid

作　　者：李志军[1] 杨金荣 刘洪佶 徐博[1] LI Zhijun;YANG Jinrong;LIU Hongji;XU Bo(State Key Laboratory for Reliability and Intelligence of Electrical Equipment Co-Built by the Provincial and Central Governments,Hebei University of Technology,Tianjin 300130,China)

机构地区：[1]河北工业大学省部共建电工装备可靠性与智能化国家重点实验室,天津300130

出　　处：《电网与清洁能源》2024年第6期145-154,共10页Power System and Clean Energy

基　　金：河北省重点研发计划资助项目(20312102D)。

摘　　要：为抑制“双高”背景下新型电力系统中日趋复杂的电网背景谐波,并网系统通常需要在已有控制方案基础上附加PCC节点电压前馈策略。而现有研究表明,在弱电网下由于并网逆变器与电网阻抗之间的相互作用,该策略会降低并网逆变器等效输出阻抗在中低频段内的无源性,易引发并网系统产生宽频谐振问题。针对这一问题,通过建立弱电网下并网逆变器系统等效输出阻抗模型剖析了传统PCC节点电压前馈策略在抑制电网背景谐波方面的优点及固有缺陷;并在此基础上基于无源性理论提出了一种新型网侧有源阻尼策略,该策略通过在电容支路增加有源补偿装置与主逆变器附加控制相结合,不仅实现了并网逆变器系统等效输出阻抗在宽频段范围内的充分无源,且能有效抑制电网背景谐波,提高并网系统在弱电网下的稳定性与适应性。通过搭建系统仿真模型对所提控制策略在并网逆变器接入弱电网时的有效性进行了验证。To suppress the increasingly complex grid background harmonics in the new power system under the“Dual High”background,the grid-connected system usually needs to add the PCC node voltage feedforward control strategy on top of the existing control scheme.However,existing studies have shown that due to the interplay between the inverter and the grid impedance under weak grid this strategy would reduce the passivity of the equivalent output impedance of the grid-connected inverter in the middle and low frequency band,which is easy to cause the broadband resonance of the grid-connected system.To address this issue,firstly,the advantages and inherent defects of the traditional PCC node voltage feedforward strategy in suppressing grid background harmonics are analyzed by establishing the equivalent output impedance model of the grid-connected inverter system under weak grid,and on this basis,a new network-side active damping strategy is proposed based on the theory of passivity,which not only realizes the full passive equivalent output impedance of the grid-connected inverter system in a wide frequency range by adding active compensation device in the capacitor branch and the additional control strategy of the main inverter,but also effectively represses the grid harmonics disturbance and greatly enhances the adaptability of the system under weak grid.Finally,the validity of the control strategy is proved by building the system emulation model when the grid-connected inverter is connected to a weak grid.

关 键 词：弱电网 并网逆变器 无源性 谐振抑制 有源阻尼 

分 类 号：TM464[电气工程—电器]