考虑全前馈的重复控制逆变器稳定性提升策略  

Stability Improvement Strategy of Inverters With Grid Voltage Full Feedforward and Repetitive Control Under Weak Grid

作　　者：竺明哲 刘佳庆 吕昊 葛乐[1] ZHU Ming-zhe;LIU Jia-qing;LV Hao;GE Le(Nanjing Institute of Technology,School of Electrical Engineering,Nanjing 211167,China)

机构地区：[1]南京工程学院电力工程学院,江苏南京211167

出　　处：《电力电子技术》2025年第2期8-12,共5页Power Electronics

基　　金：江苏省高等学校基础科学(自然科学)研究面上项目(22KJB470013);江苏省配电网智能技术与装备协同创新中心开放基金项目(XTCX202205)。

摘　　要：电网电压全前馈可以提高重复控制并网逆变器的动态性能,同时抑制电网电压背景谐波对并网电流的影响。然而全前馈环节的引入会使重复控制并网逆变器在弱电网下的稳定性变差。本文研究了采用电网电压全前馈的重复控制并网逆变器在弱电网下稳定性提升策略,首先建立了包含电网阻抗和电网电压前馈的等效数字控制对象,通过小增益定理稳定性分析方法可知,降低系统无重复控制时的闭环传递函数增益有利于系统稳定。对此,本文提出了在全前馈环节中加入一阶低通滤波器,提高了系统的稳定性。谐波抑制效果分析表明,改进全前馈为系统提供了良好的谐波抑制能力。搭建了一台20kW逆变器样机并进行实验,结果表明该策略可以有效提高系统稳定性。The grid voltage full feedforward can improve the dynamic performance of the inverter using repetitive con-trol and suppress the influence of background harmonics of grid voltage on the grid-tied current,however,the stability of the inverter will deteriorate under weak grid.The stability improvement strategy of the grid-tied inverter with repeti-tive control and grid voltage full feedforward under weak grid is investigated.Firstly,the equivalent digital control plant containing grid impedance and grid voltage feedforward is established,the small gain theorem stability analysis method shows that reducing the closed-loop transfer function gain of the system without repetitive control is beneficial to the system stability.In this regard,the addition of a first-order low-pass filter in the full feedforward to improve the stability of the system is proposed.The analysis of the harmonic suppression effect shows that the improved full feed-forward provides good harmonic suppression capability for the system.A 20 kW inverter is built and experimented,and the results show that this strategy can effectively improve the system stability.

关 键 词：逆变器 电网电压全前馈 重复控制 弱电网 

分 类 号：TM464[电气工程—电器]