Research On Energy Storage Technology Of DC Power Distribution System For More Electric Aircraft

The electrification of airborne equipment in more electric aircraft can effectively reduce carbon emissions during the flight of the aircraft.At the same time,a large number of electrical loads are connected to the airborne DC distribution network,which impacts the power grid voltage.Connecting energy storage technology to the grid is of great significance for its stable operation.In order to meet the modular development trend of airborne equipment,an electric accumulator unit(EAU)that can be retrofitted to the airborne 270 V DC distribution network is designed,and it is modeled and simulated from component to system.First,the power supply method of the more electric aircraft is analyzed,the internal energy storage scheme of the EAU is determined,and the internal and external circuit topology of the EAU applied to the airborne DC distribution network is designed.In order to meet the requirements of high efficiency and high power two-way transmission,the CLLLC type DC converter was applied to the airborne energy storage module EAU,the dynamic working process of the converter was analyzed,and its steady-state operating characteristics were discussed in detail.A PFM + soft-start double-layer control strategy for the converter circuit is proposed which is compared and verified by simulation and experiment.In addition,in order to optimize the matching scheme of the internal energy storage components of the EAU,load power distribution is performed first.According to the topology of the EAU access system,a mathematical model of the battery and the super capacitor is established,and their combined power supply characteristics are analyzed.At the same time,the multi-objective optimization mathematical model is established with initial installation cost,system weight and maintenance and replacement cost of the battery and supercapacitor,and the matching schemes of the battery and supercapacitor are selected by using improved ECSA algorithm with elite strategy so as to obtain the optimal configuration scheme that satisfies system constraints and verify the effectiveness of the algorithm in scheme selection.Finally,the modeling of each component inside the EAU is completed and a virtual simulation experiment platform is established according to the system circuit topology.The comparison simulation with or without EAU of the system proves that the proposed energy storage technology can keep the voltage of the onboard DC distribution network stable.