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

Abstract

As a new type of microgrid structure, hybrid AC/DC microgrid can efficiently consume photovoltaic-based distributed renewable energy, fitting for the circumstances where electric vehicles work as the main load. Unlike the voltage of AC bus, the DC bus voltage of the hybrid AC/DC microgrid has typical low inertia guaranteed by the power electronic equipment connected to it. Thus, how to enhance the DC bus inertia of hybrid AC/DC microgrid system and improve the stability of DC bus voltage become particularly important. To solve these two problems, this paper presents a flexible method of coordinated control of microgrid bus voltages. The P/U droop characteristics of DC ports of power electronic equipment, such as energy storage and charging and discharging equipment for electric vehicles are taken into account, meanwhile the power reserve rate and energy reserve rate of various distributed renewable energy are comprehensively considered. Under the use of curve translation and other adjustment methods flexibly, DC bus voltage stability is maximized in different working conditions and stable operation of the hybrid AC/DC microgrid system is guaranteed. The validity of the proposed method is also verified by establishing a matlab/simulink simulation system.