Capacity Optimization Of Hybrid Energy Storage On PSO Algorithm

In order to improve the stability and reliability of the power system, and to achieve electricity supply day and night, established wind-solar power generation systems in the region with abundant solar and wind resources. However, owing to intermittent and instability of wind, solar power output and the high cost of the system, the energy storage devices should be allocated to flatten the power fluctuations. The ultracapacitor energy storage has the advantages of high power density, fast speed of charging and discharging, long life servicing, and battery energy storage has the advantages of mature battery energy storage technology and cheap price etc, but it has big volume and weight, low power density, and short service life. Using the complementary characteristics of battery and ultracapacitor, ultracapacitor and battery as energy storage devices of wind-solar hybrid power system, was mixed.Firstly, the characteristics of solar cell, wind turbine, battery and ultracapacitor was analyzed, and three hybrid energy storage models, named the direct parallel connection, parallel connection through the inductors, through the power converters respectively are established. Theoretical analysis and simulation results demonstrated that the hybrid energy storage system can improve the capacity of system power output, reduce the output current of the storage battery, extend the working time and reduce the internal loss. Secondly, it establishes the capacity optimization model for independent wind generation system, which considers the lowest life cycle cost of hybrid energy storing device as the optimization objective, and considers the indices such as the loss of power supply probability as constrain conditions. The advantages and disadvantages of traditional battery energy storage, improved battery energy storage, the traditional hybrid energy storage and improved hybrid energy storage are compared. Thirdly, A hybrid energy storage capacity optimization model was constructed, which considers battery and ultracapacitor as a hybrid energy storage device, considers the lowest annual life cycle cost of hybrid energy storing device as the optimization objective, and considers the indices such as the power distribution reliability as constrain conditions. Then solves the problem with standard PSO algorithm, weight improved PSO and asymmetric acceleration coefficient improved PSO algorithm. Finally, by simulating the model of hybrid energy storage capacity optimization for independent wind generation system and capacity optimization of hybrid energy storage for wind-solar generation system in MATLAB software. The results shown that the improved hybrid energy storage system has a lower life cycle cost, and the acceleration factor improved PSO algorithm can get better optimization results, not only can accelerate the convergence speed, but also reduce life cycle cost.