Research On Hybrid Energy Storage System Based On Virtual Synchronous Generator

As the energy and environmental problem become more and more serious, it has achieved a high degree of consensus to develop the distributed energy generation and accelerate in the adjustment of energy structure in the world. As a method of distributed energy generation connecting to large power system, Microgrid has attracted much attention. Because of the volatility and intermittent of renewable energy sources, configuration of energy storage system in the Microgrid are needed to improve the stability and reliability of power supply of renewable energy and ensure the stable operation of microgrid systems.According to the characteristics of composite energy storage system, this paper not only have built models of two energy storage element, that is, the lead-acid battery and super capacitor, but also analysed the characteristics of them. It determines the topology structure of the composite energy storage system, and then researches the control strategy of DC/DC converter and DC/AC converter of the composite storage system. A control strategy named Virtual Synchronous Generator(VSG) is used in inverter control of the energy storage system. Finally it simulats and verifies the main performance of the whole system.In terms of composite energy storage, this paper first selects lead-acid battery and super capacitor as the energy storage element for it through the analysis of main storage technology, then it simulats and models the lead-acid battery and the super capacitor. After that, it determine the topology of composite energy storage system through analysis and comparison. Finally it studies and compares DC side and AC side control strategy of composite energy storage.In terms of VSG research, this paper first model the VSG through analysis and comparison with the model and related equations of synchronous generator. Secondly, through the study of VSG control method combined with the characteristic of composite energy storage system, according to different working cond itions, it designs VSG control method. Finally, it elaborates the main points of VSG design realization.Finally, based on the analysis of composite energy storage system and the converter control strategy, this paper expounds the hardware design principle and the design ideas of the composite energy storage system. Then it narrates the general idea of VSG software and other related design. Through modeling composite energy storage system, it has verified the characteristics of designed composite energy storage system on off grid, grid connected operation conditions. It has also compared the differences in characteristic of the system between traditional control strategy and new control strategy. It has shown the better performance and vast development prospect of VSG, compared with the traditional method.