Research on Energy Management and Its Control Strategies of Microgrid

Abstract

In this paper, the microgrid which is composed of photovoltaic cells, microturbine, storage device and load is researched. On the basis of analysis of the typical structure of microgrid and the operation modes of every microsource, the program of energy management is presented and designed, and its control strategies are researched under the condition of both grid-connected mode and islanding mode. Several algorithmic examples have been studied through simulation, and the simulation results verify the correctness of the energy management's control strategies. The research results indicate that it can ensure the high efficiency and stability operation of microgrid through the coordinated control of energy management. In recent years, with the increasing emergence of worldwide energy pressure and various disadvantages of extra- large scale power system, Technology of Distributed generation which is represented by solar energy power generation system and wind energy generation system has got more and more recognition. However, some bottleneck problems exist such as high cost of single machine being connected into power grid, difficulties in controlling; a great impact on the network exists in the development. An effective solution to these problems is to develop microgrid technology. Microgrid is a system which is composed with load and microsource and expressed as a single controlled unit to network and a customizable source to user. Microsource is the core unit of microgrid, the electric energy switching, grid- connection and necessary energy control of which is accomplished by power electronic equipment. In insuring the normal running of microgrid under the condition of both grid- connected mode and islanding mode, it is a key problem in research of microgrid technology that how to manage these individual sources reasonably in order that microgrid can meet the demands of users in power quality and achieve ideal economic efficiency effects. It is an effective way in researching and developing energy management of microgrid in order to ensure flexible running mode and high-quality power supply service, solving all problems such as voltage control, load flow control, load distribution when system is disconnected, stability and operation. In this paper, according to the analysis of the typical structure of microgrid and the operation modes of every microsource, the program of energy management is presented and designed, and its control strategies are researched under the condition of both grid-connected mode and islanding mode. Several algorithmic examples have been studied through simulation, and the simulation results verify the correctness of the energy management's control strategies.