Parallel inverter control for power sharing i...

Parallel inverter control for power sharing in islanded operation of AC micro-grid

Author Name : Guo-Jie Li, Suleman Haider

Abstract: The key issues related to Micro-grids (MG) have concentration to massive struggle to expand their penetration in power systems especially when system works parallel in the islanded mode. The distributed generators (DGs) in the islanding operation of the micro-grid are commonly coupled via inverters to an AC distributed system.The aim of this study is to investigate the feasibility of power sharing among parallel distributed generators (DGs). In this paper modeling and control of parallel inverters are presented. The frequency and voltage variation caused by connecting two inverters in parallel is an issue in droop control strategy. To address these issues, the DG units are interfaced with two parallel inverters in an islanded mode. The enhanced droop control implemented for frequency restoration and voltage control among the distributed generators with predefined droop characteristics. The PQ control is investigated for controlling output real and reactive power of the distributed generator by assigning their references. The study proposes islanded operation in the AC Micro-grid without communication link under enhanced droop control. The inverter has been implemented using the MATLAB/SIMULINK environment. The results show validity and power sharing performance of the system while maintaining stable operation when the DGs work in the islanding mode.1