Micro Power Grid Hybrid Energy Storage System Optimization Control Strategy Research

The installed capacity of solar and other renewable energy is continuously rising,and for photovoltaic power plant,it is planned to reach 150 GW by our nation at the end of the "13th Five-Year plan".The installed capacity of distributed power plants is expected to reach 70 GW which will occupy nearly half of the whole,and that of the centralized ground plants is 80 GW.However,the power output of renewable energy such as solar energy has characteristics of randomness and timeliness,thereby it is difficult to make the load of the micro grid operate steadily.Frequent fluctuations in a short period of time in the power generation is also a severe challenge of the power quality of the micro grid.The hybrid energy storage system,as an adjustable resource,can compensate for the defect of renewable energy.Through corresponding control strategy,it can smooth the power fluctuation of renewable energy and improve the power quality.At the same time,the capacity ratio of the hybrid energy storage system is considered,and the operating cost of the hybrid energy storage system can be reduced.The main work of this paper is as follows:Firstly,an overview of the background is presented,the current research situation of micro grid and hybrid energy storage system is analyzed.Wind energy is set as an example to study the current problems of scheduling and storage of renewable energy.The problems to be solved in this paper are proposed.Secondly,the properties of the different storage units(super capacitor and battery)in hybrid energy storage system are analyzed.According to the properties,the topological structure of the hybrid energy storage system is designed,and the working principles of DC/DC converter is introduced.A dual filter is designed and optimized.The first filter adaptively adjusts the parameters according to the current state of renewable energy,optimizes the output power of it,and stabilizes the output power fluctuation.The second filter adjusts filter parameters according to the state of hybrid energy storage system and allocates power of the two kinds of energy storage mediums,then suppresses the output power fluctuations of renewable energy with the power used by implementing agencies when assigning different storage units.Thirdly,the control strategy of the connection of hybrid energy storage system,renewable resources and micro grid is established.The multi objective function is put forward to stabilize the fluctuations of the renewable resources and meet the current power demand distribution.It is of lowest cost for hybrid energy storage configuration.According to the operation condition of the hybrid energy storage,the limiting conditions are set up to ensure the stable and reliable operation of the micro grid.Then,according to the importance of each objective function in different scheduling period,the multi-objective function is proposed as a fitting method.Fourthly,particle swarm optimization algorithm is used to solve multi-objective function.The traditional particle swarm optimization algorithm is improved firstly by adding inertia weight adaptive strategy and worst particle elimination strategy in order to solve the shortcomings of the traditional particle swarm optimization algorithm which is easy to fall into premature.Finally,the improved particle swarm optimization algorithm is used to solve the objective function.Fifthly,software and hardware experimental platform is built.The overall design of the software and hardware platform of the control strategy is done.By comparing and analyzing the power fluctuation of storage battery and super capacitor in the hybrid energy storage system,the power distribution is directly reflected.By comparing the power fluctuations of battery and super capacitor,the power distribution is reflected.Comparing with the traditional hybrid control strategy of hybrid energy storage,it is proved that the optimized hybrid energy storage control strategy can save 4.3% of the cost and the performance to stabilize the power fluctuation of renewable energy has also been significantly improved.It can be proved that the energy management strategy proposed in this paper has some theoretical significances and practical application value.