并网逆变器LCL接口直接输出电流控制建模及稳定性分析  

Modelling and Stability Analysis of Direct Output Current Control for LCL Interfaced Grid-Connected Inverters

作　　者：郭小强[1] 邬伟扬[1] 顾和荣[1] 王立乔[1] 赵清林[1] 

机构地区：[1]燕山大学电气工程学院电力电子节能与传动控制河北省重点实验室,秦皇岛066004

出　　处：《电工技术学报》2010年第3期102-109,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学重点基金(50837003);国家自然科学基金(50977081);河北省自然科学基金(E2008000801);燕山大学优秀博士生基金资助项目

摘　　要：并网逆变器LCL接口直接输出电流控制存在不稳定的现象。为了揭示其本质,建立了系统线性控制模型,推导出系统特征方程,根据Routh-Hurwitz稳定判据得出重要结论:并网逆变器LCL接口直接输出电流无论采用P、PI还是PID控制,系统均不稳定。该问题简单直接的解决方案是在LCL上串联电阻,以增大相角裕度,提高系统稳定性。本文在系统线性模型的基础上,针对电阻三种可能的串联位置,深入分析了电阻大小、调节器参数以及稳定裕度之间的内在联系并得出精确量化的结论,最后探讨了系统非线性因素如开关动作和过调制饱和等对结论有效性的影响。Instability phenomenon exists in practical applications of the direct output current control for LCL interfaced grid-connected inverters. In order to clarify its nature, the system control linear model is developed, and the characteristic equations are deduced. Based on the Routh-Hurwitz stability criterion, a significant conclusion is reached that instability is unavoidable whatever P, PI or PID control is used. A straightforward solution is to put resistors in series with the LCL filter so as to increase the phase margin and improve the system stability. The relationship between resistances, control parameters and stability margins is analyzed and quantified precisely. Finally, the influence of nonlinear factors such as the switching and over modulation saturation on the validity of conclusions is discussed.

关 键 词：并网逆变器 LCL 接口 直接输出电流控制 稳定性分析 

分 类 号：TM46[电气工程—电器]