Operation And Control Research Of Wind/PV Hybrid Micro-grid

With the global energy and environmental issues become increasingly prominent, a variety of distributed generation technologies become the focus of world attention. However, large grid with a lot of distributed powers has many adverse effects. The emergence of the micro-grid technology is able to solve this contradiction. Flexible operation of the micro-grid and high-quality power supply services as well as green and efficient economic performance, making it a national research focus. Micro-grid system consists of a variety of distributed energy, including the main wind turbine, photovoltaic cells, fuel cells, energy storage battery. Among them, the development of wind turbines and photovoltaic cells is the most rapid and mature. The trend of wind and solar has a natural complementarity, wind/PV hybrid micro-grid has a higher supply reliability. On the operation and control of its research has the important practical significance.The goal of this paper is to establish the micro-network operation control simulation platform using PSCAD/EMTDC. The practical engineering models of wind farms and photovoltaic cells in the micro-grid is discussed. The operation and control strategy of micro-grid in the grid-connected and the islanding modes is on detailed studied. And verify the correctness of the model and the feasibility of control strategy by simulation. This paper can be summarized from the following three aspects:First, it detailed the mathematical model of the main part of the photovoltaic cells and the direct-driven wind turbine. According to the structure and parameters of the designed circuit, we built a practicality and versatility engineering model in PSCAD/EMTDC. A photovoltaic cell’s maximum power point tracking algorithm is proposed based on the perturbation and observation method. And also the wind energy capture technology is discussed in this capter. Each model has a good dynamic performance, and a better ability to adapt to changes in the external environment. Secondly, the grid connected control of the permanent magnet direct-driven wind turbine and two-level photovoltaic cells is discussed. Starting from the basic inverter structure, the basic principles and main structure of the two kinds of micro power inverter, and different grid control mode of the inverter strategy, especially PQ control and V/f control are studied. And use PSCAD/EMTDC to simulate and analyze.Finally, in order to create micro-grid operation control simulation platform, it erected a wind/PV hybrid micro-grid based on the permanent magnet direct-driven wind turbine, two-level photovoltaic systems and energy storage battery. Two typical micro-grid control mode:the master-slave control and peer-to-peer control are analysised and compared. Micro-network with the proposed micro-grid control strategy is simulated and analyzed. Then, the operation variations of the microgrid are respectively analyzed when it runs from grid-connected mode to islanding mode or vice versa, when it runs with load changes in islanding mode, etc. The system has a good dynamic performance.