| Microgrid can be divided into DC microgrid, AC microgrid and hybrid microgrid. Their investment and operating costs are not the same because of different structure and property. DC microgrid has higher reliability and less loss in the case of short distance transmission than the AC microgrid. AC microgrid is more efficient in the case of long distance transmission than the DC microgrid. Hybrid microgrid comprises DC microgrids and AC microgrids interconnected by power electronic interfaces. If DC microgrids are configurated in the place of gathering photovoltaic, fuel cell, storage link, DC load and AC load based on inverter and AC microgrids are configurated in the place where the microsoures and loads are relatively dispersive, then forming a hybrid microgrid interconnected by power electronic interfaces. On the one hand the hybrid microgrid can give full play to the respective advantages of AC microgrid and DC microgrid; on the other hand it can improve the efficiency, ameliorate power quality and enhance the robustness.Although hybrid microgrid has a greater degree of freedom theoretically in optimizing the configuration and running, the implementation is depended on the reasonable control design. So this paper carry out research on the control strategy of hybrid microgrid and the main works of this thesis are divided into the following areas:(1) Based on the proposing structure of the hybrid microgrid, establish the mathematical model of important elements;(2) Propose the control strategy of DC microgrid and AC microgrid respectively. Based on the proposing control strategy, the elements of DC microgrid and AC microgrid will take the appropriate mode of operation according to the state to ensure efficient, economic and reliable operation;(3) Futher put forward the control strategy of interlinking converters. It can not only make full use of coordinating of AC microgrid and DC microgrid, but also avoid the meaningless energy transmission loss;(4)The simulation research is carried out in the MATLAB/simulink platform about the proposing control strategy of hybrid microgrid to Validate the feasibility and validity of the control strategy. |
