基于虚拟同步发电机的微网运行模式无缝切换控制策略

Seamless Switching Control Strategy for Microgrid Operation Modes Based on Virtual Synchronous Generator

对于采用对等控制策略的微网系统,如何实现孤岛/并网运行模式间的无缝切换是一项亟待克服的技术难点。文中首先介绍微网系统的基本结构与工作模式,针对微网孤岛与并网运行模式的特点,提出一种满足微网孤岛/并网切换的虚拟同步发电机(VSG)控制策略。其次,为了适应微网的并网运行特性,提出一种基于控制器状态跟随的并行切换方法,即PQ控制的电流源模式和VSG控制的电压源模式的相位和电流指令都实时跟踪,为PQ/VSG控制模式间的无缝切换奠定基础。最后,建立微网系统的仿真模型和实验平台,共同验证了所提控制策略和并行切换方法的有效性。

For the microgrid system with peer-peer control strategies,seamless switching between islanded and grid-connected operation modes remains a technical barrier need to be solved urgently.This paper introduces the basic structure and the operating mode of a microgrid.According to the characteristics of the islanded and the grid-connected operation modes,a virtual synchronous generator（VSG）control strategy is proposed to switch the operation modes.Besides,aparalleled switching method based on the controller state following is proposed to meet grid-connected operation characteristics of the microgrid.Both phase and current instructions of the current-source mode based on PQ control and the voltage-source mode based on VSG control are tracked in real time,and it can lay a foundation for seamless switching between the two modes.Finally,both simulation and experimental platforms are established.They verify the effectiveness of the proposed strategies.