Study On Micro Grid Oriented Coordinated Control Strategy And Optimal Allocation Of Energy Storage Capacity Of Micro PV-storage Device

With the rapid development of economy,energy crisis and environmental problems have become increasingly serious,renewable energy is arousing more and more attention from many countries,especially the PV system.Due to the randomness and volatility of PV,the load in the stand-alone PV system cannot obtain the sustained and reliable electricity energy.In order to improve the power supply reliability and guarantee electricity quality of the stand-alone PV system,it is necessary to configure a certain amount of energy storage equipment in the system and control the storage equipment reasonably to ensure the stability of the system.In this paper,the capacity optimization and control strategy of the energy storage system in the PV micro-grid system are studied.The main contents are as follows: In this paper,a stand-alone micro-grid based on PV-storage device is proposed,which still consists of battery-ultracapacitor hybrid energy storage system,control system and load.Firstly,this paper conduct research on the control strategy of micro PV-storage system,introduce the operational principle of the system and put forward a power weight control method to control the system.The battery in the system is mainly used to adjust the power weight,so that each micro PV-storage system is able to work in its maximum power point respectively,and then obtain the maximum output power of the whole system.At last,the method is verified by simulation,the results show that the method can improve the output power of the system.Secondly,this paper builds models of different parts of the micro PV-storage system.Besides,the energy storage capacity optimization model of the system is established,the objective function is the minimum cost of whole life-cycle operation of energy storage system,which mainly considers the power weight change.By using the improved particle swarm algorithm to solve and analyse the given example,the correctness of the energy storage capacity optimization model that is based on the micro PV-storage is demonstrated.By using this model,maximum power output of the system is realized and the economic performance of the energy storage system is ensured.In addition,this paper presents a battery-supercapacitor hybrid energy storage capacity optimization model,the objective function is the minimum cost of whole life cycle of hybrid energy storage system.The capacity of hybrid energy storage system can be determined from two aspects: the energy supply and the power supply capability.By using the improved particle swarm algorithm to solve and analyse the given example,the correctness of the hybrid energy storage capacity optimization model is demonstrated,and the investment cost of the energy storage equipment is saved.