基于ESO和终端滑模控制的虚拟同步发电机研究

微电网是由分布式电源、储能装置和负荷等组成的统一整体,其在孤网模式下运行时,主控微源对电压和频率的控制能力对于微电网的稳定至关重要。受电力电子器件固有特点的影响,微网孤网运行的稳定性较差。为实现主控微源对交流微网的调节作用,提高交流微电网孤网运行稳定性,在DIg SILENT中搭建了光储系统作为主电源的交流微电网。然后依据虚拟同步发电控制技术和非线性鲁棒控制技术对逆变器设计了虚拟同步发电控制器,在功频控制器中引入扩张状态观测器和终端滑模控制来改善控制性能。通过仿真分析,虚拟同步发电控制在负荷波动和光伏出力波动时能有效调节微网的电压和频率。通过与一般的控制器仿真结果进行对比,基于ESO和终端滑模控制的虚拟同步发电控制不仅能实现微网调频调压功能,还能有效提高暂态频率稳定性,增大交流微网惯性。

Research of VSG based on ESO and terminal sliding mode control

Microgrid is a unified whole which is composed of distributed power sources, energy storage device and load. Main source control ability of voltage and frequency is crucial to stability of microgrid when it is isolated network running. Due to inherent characteristics of power electronic devices, the stability of mircogrid isolated running is poor. In order to realize regulating function of frequency and voltage of the main control source in AC mircogrid and improve frequency stability of the AC microgrid operation, a mircogrid with solar and storage system as main power supply is built under DigSILENT. Then a VSG controller based on virtual synchronous generation control technology and nonlinear robust control technology is designed to inverter. The Expansion State Observer (ESO) and Terminal Sliding Mode Control (TMSC) are introduced into the power-frequency controller to improve the control performance. Through simulation analysis, VSG controller can effectively regulate the frequency and voltage of microgrid when load or photovaltaic power changes. By comparing with the general controller simulation, the VSG control based on ESO and TMSC can not only realize frequency and voltage regulation of microgrid, but also improve the transient frequency stability more significantly and increase the inertia of AC microgrid. This work is supported by National Natural Science Foundation of China (No. 60971077).