Research On Optimal Configuration Of Hybrid Energy Storage Capacity With Renewable Energy

With the continuous development and large-scale utilization of renewable energy,the flexibility challenges of the power system considering high proportion of renewable energy is faced.Energy storage technology can not only smooth the volatility and randomness of renewable energy generation power,but al so effectively solve the problem of insufficient peak cutting and valley filling capacity of the power system.There are many types of energy storage with different characteristics.They have complementary advantages of energy storage technology in capacity scale,response time,cost minimization,and technological maturity.The hybridization of two or more types of energy storage technologies can effectively improve the grid-connected capacity of renewable energy,and continuous stable operation capacity of power system.Therefore,how to configure capacity and distribute power for hybrid energy storage systems has become an important research direction for domestic and foreign scholars.This paper studies the capacity configuration and power distribution of hybrid energy storage system,including the characteristic analysis and modeling of renewable energy generation system,the strategy of optimal capacity configuration and power distribution control of hybrid energy storage system.The specific work covers the following:1.Based on power demand of users and renewable energy generation,a largescale hybrid energy storage system consisting of gravity energy storage,battery and supercapacitor is constructed.For different characteristics,a strategy of optimal capacity configuration of hybrid energy storage based on adaptive variational mode decomposition is proposed,with the goal of minimizing the annual cost of th e energy storage system.Setting the maximum decomposition scale of VMD,iterating the number of low,medium and high frequency modes,the initial powers of the energy storage system are determined,and its rated power,rated capacity and annual cost are calculated.Finally,the capacity configuration scheme of the economic optimal system is determined.Under the circumstances of different decomposition scale K and the frequency demarcation points,the capacity configuration of hybrid energy storage system is simulated and analyzed.The results show the strategy can effectively improve the economy and technical rationality of large-scale renewable energy power generation system.2.Based on the operating life of the battery and the investment cost of the supercapacitor,the charge and discharge power of the energy storage system is controlled.According to the reference power signal of energy storage system,a fuzzy optimization control strategy of SOC based on variational modal decomposition is proposed.On the basis of obtaining the initial power distribution of the hybrid energy storage system,combined with the SOC of supercapacitor/ battery and its changing trend,the power of HESS could be adaptively adjust ed by the fuzzy control method.The results of simulation show that the strategy can effectively smooth the fluctuation of renewable energy power generation,and ensure the efficient and stable operation of the hybrid energy storage system.