并网逆变器电网阻抗检测技术综述

Review of Grid Impedance Estimation for Gird-Connected Inverter

分布式发电系统中,并网逆变器的性能同电网阻抗密切相关,而电网阻抗随着时间和电网运行状态的变化而变化,因此精确的电网阻抗测量是实现并网逆变器在弱电网场合下高性能自适应控制的关键技术。已有文献研究了电网阻抗测量技术并提出了一些可行的方法,但已有研究未明晰各方法的优缺点。为此,分类整理了已有的电网阻抗测量方法,将其分为主动测量方式,被动测量方式和准被动测量方式3大类,并且评述了各方法的特性、优缺点和适用场合。最后指出了目前还待解决的一些问题。

The performance of grid-connected inverter is closely related to the grid impedance in distributed power generation systems. However, the grid impedance usually varies with the change of the grid operation condition. Therefore, accurate grid impedance estimation is one of the key technologies to achieve the high performance adaptive control of the inverter which connects to a weak grid. Recently, many literatures proposed and studied the methods for grid impedance measurements. However, the merits and demerits of different methods have not been discussed deeply. For this reason, this paper presents a review of the various methods for grid impedance measurement. The existing methods are classified into three main categories： active methods, passive methods and quasi-passive methods. Moreover, the characteristics of these methods are investigated, and the merits and demerits and suitable application of each method are also discussed. At last, some issues to be solved are pointed out.