Research And Implementation Of Islanded Micro-grid Control Technology

With the rapid development of economy and society, people’s demand for energy is increasing. The traditional structure of energy consumption can not meet people’s need for energy. Electrical energy has been widely used because of its green performance. However, there are some drawbacks in the operation of traditional main power grid, and it is difficult to meet people’s requirements for the power supply in the remote areas of isolated islands. The micro-grid came into being with its flexible and reliable performance. Therefore developing new energy and micro-grid technology is an inevitable choice to solve the problems between energy shortages and environmental pollutions. This paper focuses on the situation that it is difficult to use the electricity for some people in remote areas such as islands to meet people’s demand for electricity by researching technology of islanded micro-grid.Firstly, the paper introduces the compositions of islanded micro-grid system, and analyzes the principles and output characteristics of distributed powers, and thus the performance parameters and working conditions of the battery are studied. The architecture of islanded micro-grid is based on DC bus with a comparative analysis. Finally, The study introduces the control technology of micro-grid operation, and selects the hierarchical control method with main control unit of a central controller to realize system control. The central controller is responsible for the control of entire system and local controllers complete the control of distributed powers.The article completes the study of energy management strategy during the design of central controller, and uses the correcting hard-charging method to increase the life of the battery and improve the economics of system. Then the paper accomplishes the design of hardware circuit with high performance MSP430as the main chip, and completes debugging and testing of the hardware circuit.The local controller is mainly designed for the photovoltaic in the design of local system. The three-stage charging method including maximum power point tracking (MPPT) charging, constant voltage charging and float charging, is selected by researching the operating characteristics of the battery and photovoltaic cells. The MPPT charging is completed by the perturbation and observation method. The article completes the hardware and software design of the local controller with experimental testing.Finally, the paper builds a testing platform for islanded micro-grid system to verify the performance of the control system by experimental testing. The article has an important reference significance for the practical application of islanded micro-grid.