并网LCL滤波的PWM整流器输入阻抗分析  

Input Impedance Analysis of LCL-Filter PWM Rectifier Connected to Grid

作　　者：李芬[1] 邹旭东[1] 邹云屏[1] 石晶[1] 吴振兴[1] 王成智[1] 唐健[1] 

机构地区：[1]华中科技大学电气与电子工程学院,武汉430074

出　　处：《电工技术学报》2010年第1期97-103,共7页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(50977036)

摘　　要：对并网LCL滤波的PWM整流器进行了深入研究,在电流环中通过引入滤波电容电流反馈控制来改变系统极点分布,抑制LCL滤波器自身的谐振和增加系统稳定性,以代替阻尼电阻的作用。将控制器参数和物理模型结合建立了LCL滤波整流器的闭环高频输入阻抗模型,详细地分析了整流模式、有源逆变模式下阻抗特性,并研究了两种模式下公共耦合端(PCC)电压前馈的影响,为LCL滤波整流器的并网控制提供理论指导。仿真和实验结果表明,LCL滤波整流器并网时可以有效减少注入电网中高次谐波含量,而引入滤波电容反馈控制策略是一种简单、可行抑制LCL谐振的方法,带PCC电压前馈有利于并网整流器小功率能量回馈的正常运行。Due to better attenuating current harmonics around switching frequency injected to the grid,L-filter is substituted by LCL-filter in grid connection of PWM rectifier.However,because of the resonance phenomenon of LCL-filter,it may bring stability problems in the current loop.In order to overcome them,a control strategy applying the filter-capacitor current feedback in the current loop is proposed to achieve the function of damping resistor.Then,the input impedance integrated the controller with the LCL-filter parameters in high frequency region is modeled and analyzed by the frequency responses of the transfer functions models,including the consumer mode and the power feedback mode.Also,the influence of the disturbance of point of common coupling（PCC） voltage is studied.Finally,the simulation and experiment tests show that LCL-filter is effective to reduce the switching frequency pollution emitted in the grid,the proposed control strategy is feasible to solve the resonance problem of the LCL-filter,and it＇s easy to achieve power feedback operation under small power with PCC voltage feed forward.

关 键 词：PWM整流器 并网 LCL滤波器 滤波电容电流反馈 PCC电压前馈 

分 类 号：TM461[电气工程—电器]