弱电网下基于前置低通滤波器的电网电压加权前馈控制策略  

Grid Voltage Weighted Feedforward Control Strategy Based on Pre-Low Pass Filter Under Weak Grid

作　　者：王瑞斌 刘佳庆 王庆园 竺明哲 WANG Ruibin;LIU Jiaqing;WANG Qingyuan;ZHU Mingzhe(School of Electric Power Engineering,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]南京工程学院电力工程学院,南京211167

出　　处：《电力系统及其自动化学报》2025年第3期93-99,共7页Proceedings of the CSU-EPSA

基　　金：南京工程学院引进人才科研启动基金,并网逆变器谐波的重复控制抑制策略研究(YKJ202207)。

摘　　要：针对采用电网电压全前馈控制策略提升并网电能质量的LCL型逆变器运行在弱电网下存在失稳风险的问题,本文提出一种基于前置低通滤波器的电网电压加权前馈控制策略。首先,根据稳定性判据求解出在系统临界稳定时所需设计前馈环节的传递函数;然后,根据传递函数的变化趋势在电网电压前馈路径中加入二阶低通滤波器环节,并利用伯德图及数学关系合理设计低通滤波器截止频率及阻尼系数,解决了逆变器在弱电网下失稳的问题;最后,通过在6 k W的逆变器样机上进行实验,验证所提策略的有效性。Aimed at the instability risk of LCL inverters under the weak grid which widely adopt a grid voltage full feed-forward control strategy to improve the grid-connected power quality,a grid voltage weighted feedforward control strate-gy based on pre-low pass filter(LPF)is proposed in this paper.First,according to the stability criterion,the transfer function of the feedforward required to ensure the critical stability of the system is solved.Then,a second-order LPF is added to the feedforward path of grid voltage according to the changing trend of the transfer function.In addition,the cut-off frequency and damping coefficient of the LPF are reasonably designed by using the Bode plots and the mathematical relation,which solves the problem of instability of the inverter under the weak grid.Finally,experiments on a 6kW inverter prototype were carried out to verify the effectiveness of the proposed strategy.

关 键 词：电网电压全前馈 弱电网 数字延时 低通滤波器 

分 类 号：TM464[电气工程—电器]