逆变型分布式电源模型的多时间尺度降阶分析及稳定一致性证明

Multi-time Scale Model Order Reduction and Stability Consistency of IIDG System

微网中逆变型分布式电源（inverter interfaced distributed generator,IIDG）包含频率控制、测量延时和电磁暂态等多个时间尺度,是一个复杂的非线性系统。该文以微网中基于下垂控制的IIDG为研究对象,建立包含功率下垂控制器、电压电流双环控制器以及滤波器和线路的IIDG完整模型。根据奇异摄动理论,对IIDG完整模型进行多时间尺度特征划分,并对模型进行忽略快动态降阶处理。通过IIDG小信号模型的特征提取,对IIDG模型降阶前后的静态稳定一致性进行证明。利用系统稳定域边界二次近似方法,对IIDG模型降阶前后的暂态稳定一致性进行证明。通过单机系统及三机微网示范工程系统的时域仿真结果证明所提的IIDG时间尺度划分方法和降阶方法的有效性,能为微网中IIDG动态特性分析提供降阶简化模型。

Inverter interfaced distributed generator（IIDG） is a nonlinear complex system with multiple time scales including frequency control, time delay measurement and electromagnetic transient. The droop control based IIDG of microgrid was taken as research object and its detailed model consist of power droop controller, voltage-loop and current-loop controllers, filter and line were established. Based on the singular perturbation theory, the multi-time scale characteristics of the IIDG detailed model were divided, and the model order was reduced by neglecting fast dynamics. The static and transient stability consistency of IIDG original and reduced systems were demonstrated by feature extraction of IIDG small signal model and the quadratic approximation method of the stability region boundary respectively. Time-domain simulation results demonstrate the proposed model reduction method and multi-time scale division method are effective and applicable to provide simplified model for dynamic characteristic analysis of the IIDG system in microgrid.