| Microgrid is a small grid which is composed of microsources, load, energy storage device and control device. Under the pressures of environmental problems, security of grid, and shortage of resources, the concept of microgrid has been highly valued by many countries in the world and become a hot issue. And to achieve advantages of microgrid, control system is very important to microgrid. Therefore, the control of microgrid becomes the key problem in the research of microgrid. At the same time, with the development of microgrid, how to reflect the economy of the microgrid and realize the optimal operation of microgrid has become an urgent problem to be solved.This paper is based on the establishment of microgrid simulation model, according to the dynamic load has great influence on the microgrid(especially isolated island microgrid), and proposed an adaptive transient droop control method; the economy and environmental protection of microgrid are analyzed, based on the stable operation of microgrid. Through the optimization calculation of the microgrid economic mathematical model, the optimal operation of microgrid is realized. The specific work of this paper is as follows:First, this paper established a dynamic simulation model of the photovoltaic power generation, wind power generation, micro turbine, fuel cell and battery. The simulation experiment was carried out by using PSCAD/EMTDC software, and simulation results verified the correctness of the simulation model established in this paper, lay the foundation for the follow-up work;Secondly, according to the dynamic load has great influence on microgrid(especially isolated island microgrid), this paper proposed an adaptive transient droop control method. A function of transient component, power and droop coefficient was introduced to improve dynamic performance of droop control and achieve reasonable power allocation between microsources. Coordinated control strategy of microgrid is based on adaptive transient droop control and PQ control. The simulation was realized by using PSCAD/EMTDC, and results verified the correctness and effectiveness of the proposed control strategy.Then, this paper analyzed the control strategy of optimal operation for microgrid, established the mathematical model of microgrid economic operation. The combination of the microsource, the cost of the microgrid and the economic benefits are unified into an optimization problem to be solved. The optimization results of the unit output power and the operating cost of the microgrid are obtained, and verified the correctness of the mathematical model established and the effectiveness of the control strategy.Finally, according to the actual engineering requirements of the microgrid central controller, the hardware composition of the central controller, the selection of the main components and the main architecture of the software system are preliminary designed. |
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