适应并离网模式切换的DFIG电磁暂态仿真建模

Electromagnetic Transient Simulation Modeling Method of DFIG Adapted to Grid-Connected/Island Mode Transfer

目前,常用的商业仿真软件中的双馈式感应发电机(double-fed Induction Generator,DFIG)模型通常不支持离网运行模式,难以实现风力发电系统由离网到并网的全过程电磁暂态仿真,对电力系统仿真分析工作带来极大不便。研究适应并离网模式切换的DFIG电磁暂态仿真建模方法。基于模块化思想分别对风力机、异步电机、变流器以及断路器进行建模,在系统组装形成DFIG风力发电系统电磁暂态仿真模型。提出了适应并离网模式切换的DFIG受控源等效电路模型和离散时间域实现方法,通过设计状态变量矩阵元素的截取和扩充算法实现了模型在并离网模式下的无缝衔接。在MATLAB/Simulink中搭建DFIG发电系统模型对所提方法和模型进行验证,仿真结果表明,所提建模方法能够很好地支持DFIG离网运行模式,实现DFIG由离网到并网的全过程电磁暂态仿真。

Since the double-fed induction generator(DFIG)model in common commercial simulation software usually does not support island operation mode,it is difficult to realize electromagnetic transient simulation of wind power generation system during the whole process from the off-grid mode to the grid-connected mode.This paper proposes a feasible electromagnetic transient simulation modeling method for the DFIG.Firstly,based on the modular method,wind turbines,DFIG,converters,and circuit breakers are modeled separately,and assembled into an electromagnetic transient simulation model for the DFIG wind power generation system.Secondly a controlled source based equivalent circuit model of DFIG and the discrete-time implementation method adapted to grid-connected/island mode transfer are proposed and the seamless connection of the model in the off-grid and grid-connected mode is realized by designing an algorithm for intercepting and expanding the elements of the state variable matrix.Finally,an electromagnetic transient simulation model of DFIG in MATLAB/Simulink is built to validate the effectiveness of the proposed modeling method.