| Photovoltaic and wind power generation has the inherent characteristics of volatility and randomness.When large-scale renewable energy is incorporated into the power grid,it will seriously affect the power quality,safety and stability of power system.The phenomenon of "abandoning wind and abandoning light" in China has affected the utilization and development of renewable energy.Large-scale energy storage technology is a bottleneck technology to achieve the popularization and application of renewable energy.Among many energy storage devices,Vanadium Redox Flow Battery(VRB)has the characteristics of long life,large capacity,flexible design,fast response,environmental friendliness,and good charging and discharging performance,so it is highly concerned by the industry at home and abroad.In order to meet the urgent need of large-scale energy storage for the market,it is urgent to solve the key technologies of group design,integration and intelligent control in energy storage system.The multi DC/DC coordinated control strategy of Vanadium Redox Flow Battery energy storage system was studied in this dissertation.The Vanadium Redox Flow Battery is used to suppress photovoltaic fluctuations,and the control strategy is based on first order low pass filter and moving average principle.A mathematical model of Vanadium Redox Flow Battery was established to verify that the vanadium battery could suppress the fluctuation under different time scales,and the indexes of evaluating the photovoltaic power fluctuation suppression efficiency were constructed.The power output of photovoltaic energy storage system is smooth under different filtering time constants,and different capacity allocation schemes were analyzed and obtained.A multi-DC/DC parallel operation coordination of Vanadium Redox Flow Battery energy storage system was studied,and a multi-DC/DC coordinated control based on the priority principle of the most economical DC bus layer Vanadium Redox Flow Battery energy storage system was proposed.The objective function and constraint conditions of VRB capacity attenuation and the energy efficiency of energy storage system were constructed,the goal is to minimize the total operating cost of energy storage power stations and a genetic algorithm was used to optimize the power allocation for parallel operation of multiple energy storage systems.To ensure positive response of energy storage power station by double loop charging and discharging control.In the 1MW photovoltaic energy storage power station,the coordinated operation of the energy storage system with different power requirements and different states of charge in each period was simulated,and the comparison between the strategy of this dissertation and the traditional control strategy is performed.The results show that the strategy of this dissertation can better optimize the power allocation of the VRB energy storage system,and ensure that the battery pack works in the safe operation area,optimizes the running state of the energy storage power station,reduces the running cost of the energy storage system.Finally,the software and hardware of photovoltaic energy storage integrated parking station for Vanadium Redox Flow Battery energy storage system were designed,and the physical objects were built. |
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