逆变器电源短路输出电流的等效机理模型

Equivalent Mechanism Model for Short-circuit Output Current of Inverter Power Supply

逆变型分布式电源IIDG(inverter interfaced distributed generation)的短路输出特性与常规电动机电源差异很大,使得电网的短路分析计算变得更加困难。针对逆变型分布式电源短路电流特性复杂而产生的问题,本文提出了一种基于多时间尺度的IIDG短路电流等效机理模型。参照常规电机的短路电流输出特性对IIDG进行时间尺度划分,并将时间尺度分为直流电压控制时间尺度和交流电流控制时间尺度来保证模型响应的解耦性。根据并网点不同的电压跌落程度及其对应的直流/交流时间尺度,对IIDG输出的短路电流进行分时段建模和模型参数辨识。最后,通过仿真对比验证了该模型的准确性和有效性。

The short-circuit output characteristics of inverter interfaced distributed generation(IIDG)are quite different from those of the conventional motor power supply,which makes the short-circuit analysis and calculation of power grid more difficult.To solve the problem resulting from the complex short-circuit current characteristics of IIDG,an equivalent mechanism model of IIDG short-circuit current based on multiple time scales is proposed.By referring to the short-circuit current output characteristics of the conventional motor,the time scale of IIDG is divided into DC voltage control time scale and AC current control time scale to ensure the decoupling of model response.According to different voltage sags at the point of common coupling and the corresponding DC/AC time scales,the output short-circuit current of IIDG is modeled at different time intervals,and the model parameters are identified.Finally,the accuracy and effectiveness of the proposed model are compared and verified by simulations.