基于Brauer定理的多变流器并网系统小干扰稳定性分析

Analysis of the Small-signal Stability for Multiple Grid-connected-converter System Based on Brauer Theorem

高比例新能源和高比例电力电子设备(简称“双高”)并网会引起电力系统的宽频振荡问题。采用传统阻抗分析法研究多变流器并网系统(multiple grid-connected-converter system,MGCCS)小干扰稳定性问题存在一定局限。该文将多变流器并网系统建模为负反馈模型,并基于Brauer定理提出一种充分稳定性判据。最后,通过一个包含7个变流器群的并网系统验证所提判据的有效性。理论分析与时域仿真证明该判据计算复杂度较低,具有分析高阶系统小干扰稳定性问题的潜力,且其作为充分判据的保守性较低,有利于指导并网系统的参数设计。

High proportion of new energy and high proportion of power electronic equipment(referred to as“double high”)connected to the grid will cause the problem of wide band oscillation in the power system.The traditional impedance analysis method to study the small disturbance stability of multi-converter grid-connected system has some limitations.In this paper,the multi-converter grid-connected system was modeled as a negative feedback model,and a sufficient stability criterion based on Brauer theorem was proposed.The validity of the criterion was verified by a grid-connected system containing a 7-converter group.Theoretical analysis and time domain simulation show that this criterion with a low computational complexity has the potential to analyze the high-order system small disturbance stability problems,and its low conservatism as a sufficient criterion provides guidance for the parameter design of grid-connected systems.