抑制电网背景谐波影响的并网逆变器控制策略  

Control Strategy for Grid-connected Inverter to Suppress Current Distortion Effected by Background Harmonics in Grid Voltage

作　　者：王学华[1] 阮新波[1] 刘尚伟[1] 

机构地区：[1]华中科技大学电气与电子工程学院,湖北省武汉市430074

出　　处：《中国电机工程学报》2011年第6期7-14,共8页Proceedings of the CSEE

基　　金：国家自然科学基金项目(50837003;51007027);国家重点基础研究发展计划项目(973项目)(2009CB219706)~~

摘　　要：LCL型并网逆变器对高频谐波的衰减效果显著,但对电网背景谐波的抑制能力有限。提高系统环路增益可减小背景谐波的影响,但环路增益受系统稳定性影响,不可能无限增大。为有效抑制背景谐波的影响,推导LCL型并网逆变器所需要前馈电网电压的函数,并将其加入到原控制系统中,经过适当变换,提出一种基于网侧电感电压微分量和并网电流反馈的双闭环控制策略,其内环采用网侧电感电压微分量取代电容电流以阻尼谐振。该控制策略可有效抑制背景谐波对并网电流的影响,并且不需要检测电容电流。最后设计一台6 kW的原理样机,验证所提出的控制策略的正确性。The grid-connected inverter with LCL filter has the ability of easily attenuating the high frequency current harmonics.However,the effect on the current of the background harmonics in grid voltage is difficult to be suppressed.Increasing the loop gain can improve the suppression ability,but it is limited by the system stability requirement.In order to suppress the current distortion effected by the background harmonics in grid voltage,this paper calculated the feed-forward function for grid-connected inverter with an LCL filter.After simplifying the block diagram,a novel dual-loop control strategy was proposed.Instead of capacitor current,the inner loop adopts feedback of the differential voltage of filter inductor at the grid side to damp the resonance.The proposed strategy can effectively suppress the effect from background harmonics in grid voltage,and the capacitor current sensor is removed.A 6？kW prototype is built to validate the effectiveness of the proposed control strategy.

关 键 词：LCL滤波器 阻尼谐振 双闭环控制 背景谐波 并网逆变器 总谐波含量 

分 类 号：TM46[电气工程—电器]