Flexible Control Strategy of DC Bus for AC-DC Hybrid Microgrid with Electric Vehicle

Abstract: As a new type of microgrid structure, AC-DC hybrid microgrid can efficiently consume new energy distributed generator based on photovoltaics, which is very suitable for microgrid systems with electric vehicles as the main load. Unlike the AC microgrid, the DC bus of the AC-DC hybrid microgrid is a low-inertia system. How to improve the DC bus inertia of the AC-DC hybrid microgrid system and the stability of the DC bus voltage become particularly important. Based on this, this paper presents a method for flexible control strategy of microgrid bus voltage based on multi-node droop. By considering the P / U droop characteristics of DC ports of power electronic equipment such as energy storage and electric vehicle charging-discharging equipment, different types of distributed generator are comprehensively considered. The power reserve rate and energy reserve rate, through curve shift and other adjustment methods, improve the DC bus inertia, which effectively guarantees the stability of the microgrid system voltage. The validity of the proposed method is verified by building a matlab / simulik simulation system.