Research Of Independent Micro-grid Energy Storage System

Recently, micro-grid has been paid intensive attention because of the low investment, flexible networking ways and good environmental protection benefit. As a essential part of the micro grid, the energy storage system plays a crucial role in improving the power quality of micro grid and the performance of micro source, etc. Up to now, the study of micro grid energy storage system has still been in its primary stage and various kinds of energy storage techniques have still been immature. Therefore, it is of very important practical significance to explore an energy storage system with superior performance for improving the operation characteristics of micro grid, especially the independent micro grid.A new architecture for the energy storage system of independent micro-grid is proposed and studied deeply, which takes the improvement of the dynamical characteristics as the main.target. The main research work is as follows:1. The architecture of a new kind of energy storage system with multi-sources is put forward, which combines battery with super capacitor. Each module in the architecture is modeled, according to which, the control strategies of those module are deeply analyzed, which include an improved MPPT control method of photovoltaic battery and the charging and discharging control strategies of battery and super capacitor, then those strategies are tested and verified by simulation.2. According to the control principles of system, the overall control strategy is proposed, and patterns analysis is made. Each individual models and switching process are tested and verified by simulation in Matlab. 3. The design of hardware and software of the system are completed. The design of system hardware mainly include main circuit、main control circuit and peripheral circuit. Main circuit mainly consists of battery, super capacitor, PVB, BBDC and CBDC; The main control circuit and peripheral circuit mainly consist of the main control chip、sampling circuit、drive circuit and patterns choose circuit. The design of system software mainly includes the programming of the main program, the ADC sampling program and the PWM generator program.4. A100kW and1kW simulation system and a1kW experimental system are constructed, where comparative study on the experiment and simulation is finished.The research results show that the energy storage system can not only improve the dynamical performance of independent micro-grid, but also keep busbar voltage stable and make the load operate normally under different external conditions.