The Study On The Friendly Modular Microgrid Based On The Active-Parallel Hybrid Energy Storage Technique

The microgrid plays an important role in the efficient use of distributed power and renewable energy. Firstly, this paper discussed the energy storage properties of battery and supercapacitor. Then, an active-parallel hybrid energy storage system was proposed. In that hybrid energy storage system, the battery was combined with the supercapacitor by the bidirectional chopper, and therefore, the energy storage merits of battery and supercapacitor can be fully developed. At the same time, the simulation on that hybrid energy storage system was carried out to demonstrate that that hybrid energy storage topology can word effectively. In order to realize the modular design and friendly operation for the microgrid, this paper proposed a new modular topology for the ac-dc mixed microgrid which was encapsulated by the back-to-back converter. By inserting the battery-supercapacitor hybrid system into the dc/ac microgrid unit reasonably, the hybrid energy storage system could supply the rapid power and energy support for the microgrid system under different operation modes. Also, the mathematical model of that modular microgrid topology was studied. In order to realize the steady operation under different operation modes, the coordinative control methods for different converters and the control algorithms for all kinds of distributed generation, hybrid energy storage system and power load were devised optimized. It can be indicated by the simulation analysis that the modular topology of microgrid and the control strategy are feasible, and therefore the seamless switching between the grid-connected mode and the isolated mode becomes the natural property for the modular microgrid. Furthermore, we can conclude by that simulation that the active and reactive power of the modular microgrid can be dispatched precisely. As a result, the microgrid can be considered as a power/load module with multiple characteristics to realize the friendly power interaction with the power grid. Finally, this paper discussed the power quality control technology for the microgrid. By the research findings from this paper, the microgrid can be of the ability of fast networking, plug and play, seamless switching and precisely dispatched. Therefore, the characteristics of self-government, stabilization, compatibility and agility for microgrid can be fully developed.