Simulation Research Of Battery Energy Storage Systems Based On Different Models

Recently, people have laid more and more strong dependence on energy. With the continuous development, utilization and consumption of traditional energy, people will be faced with new energy shortage crisis. What’s more, with the growing concern on environmental issues, all the countries in the world began to pay more attention to the developing and utilization of new energy. Owing to the development of new energy power generation and increasing construction of distributed grid, new energy generation has well adapted to the requirement of environmental protection and sustainable development. Occupying an important position in the future energy structure, new energy have characteristic of natural resources. The output power has obvious fluctuation and intermittence, and its change may be random. It is easy to impact on the grid, which may cause gird accident, which promotes the combination of new energy generation technology and energy storage technology. Wind storage、solar storage、wind and solar storage and other new energy storage technology have played an important role on stabilizing the power fluctuation of distributed system. Stabilizing the power fluctuation mainly depends on the energy storage system performance. Therefore, understanding the operation principles and performance of battery energy storage system and doing research of battery energy storage system under different models will provide better practical value and vital significance. Firstly, review the topology structures of battery energy storage system and the current research of control strategies, and analyze each one’s merits and demerits. Based on the research and analysis of solar storage project of Sacramento Municipal Utility District(SMUD), power transfer system is composed of bidirectional BUCK/BOOST converter and three-phase full bridge converter, which are the research objects in this paper. And review the converter’s working principle and control strategies. Based on practical application, dissertation points the necessity of constant power charging/discharging in battery energy storage system. Analyze the control objects based on the goals of stabilizing the power fluctuation, select the DC bus voltage as one of the control objects and select constant power control strategy to control the charging/discharging process of battery energy storage system under the stable operation and operation principle of BESS, therefore accomplish the control of BESS.Point out the mathematic and detailed circuit models based on the analysis of operation principle of BESS. As for mathematic model, construct sliding control equation to control the DC bus link voltage through controlling the bidirectional BUCK/BOOST converter based on the theory of sliding mode control, adopt voltage oriented control combined with constant power control strategy to construct VOC control equations, and conduct mathematic model simulation to verify the feasibility of constant power control strategy. For detailed circuit model, based on the small signal model of bidirectional BUCK/BOOST converter, design two-loop control system based on two-loop average current control to realize the control of DC link voltage, and adopt constant power control strategy combined with voltage oriented control to accomplish charging/discharging for BESS under constant power to verify the feasibility of constant power control strategy. Through analysis of simulation results under the two models, get the conclusion: the battery can be charged or discharged effectively, stabilize power fluctuation and protect the battery under constant power control strategy.Finally, simulate the system under voltage jumping and power change based on the two models in MATLAB/SIMULINK. The results verified validity of the control strategy and the battery energy storage system, which provides the actual projects with some theoretical guidance for BESS.