Energy Management System Control Strategy And Software Development For AC Microgrid

The technology of distributed generation and microgrid has been taken more attention to for the tense energy relation between supply and demand these years. Renewable energy sources connected to the microgrid by the way of distributed generation increase the utilization efficiency of resource. The output power of distributed generation is fluctuant and random, so energy storage device plays an important role in microgrid. With the research of microgrid technology, increasingly equipment is connected to microgrid, and the structure of microgrid is more complex. So it is high time that an energy management system for microgrid should be laid down to coordinate the generating device, energy storage device and load by appropriate control strategy and guarantee microgrid stable operation.First, this paper introduces the research status of microgrid and its energy management system, summarizes their characteristic and research direction. The operation theory and control mode of distributed generation and energy storage device are expounded and the connection type of hybrid energy storage is analyzed. According to the feature of microgrid, a type with flexible control and easy to expand is put forward.Secondly, aiming to the trait of AC microgrid at different operating state, the corresponding control strategy is proposed. When microgrid is connected to the grid, all devices operating cost should be considered. Microgrid should run by the way of multiple constraints hierarchical optimized control strategy at this time. When microgrid is islanding, it should guarantee cooperation stability, and microgrid should use proposed multi-mode control strategy. In consideration of the difference between the two state and the feature of energy storage device, a switch control strategy is provided. The simulation result in Matlab proves that all above control strategies are effective.Thirdly, according to the structure and figure of existing microgrid in laboratory, develop a microgrid energy management system software. Microgrid monitoring system is integrated and communication system is designed. A microgrid energy management system software in upper computer is programmed to realize that all devices can be controlled and supervised and microgrid can work at several states. The software has some UI to show the situation of microgrid device and make microgrid running steadily.Finally, run software of the microgrid energy management system in upper computer. The result indicates that the energy management system conforms with the control strategy. The real microgrid can operate at different states and the response speed of energy management system is fast. The experiment proves that the energy management system software is feasible and practicable.