Research On DC-DC Of Aeronautical Static Inverter Based On Wide-input And High-power

Based on the requirements of a project,it is necessary to develop a wide input and high power aeronautical static inverter.Referring to a large number of literature and according to the requirements of project design indicators,this paper focuses on several aspects,such as wide range input,high power and high efficiency.According to the requirements of wide input and high power,after the thorough understanding of the DC-DC circuit,the push-pull forward is chosen as the main circuit of this research.In the aspect of improving efficiency,the topology is optimized to realize soft switching technology.Multi-module parallel connection is used to solve the problem of high power.The working mode of the main circuit in hard switching state is studied in depth.After analyzing the existing problems in this state,soft switching technology is introduced,and the working mode of the main circuit in soft switching state is studied in depth,and the parameters actually needed are calculated.We use simulation software to simulate and test the main circuit in two different switching states when the input is wide.The result of the analysis is that the switching loss is reduced under the soft switching mode,but the higher the input voltage,the lower the efficiency.Based on the single power supply,the requirement of high power is realized by using single parallel connection.In order to make each phase in the best state,the digital current sharing algorithm is adopted to control the output current of each module.In order to better design the controller of the current sharing link,the small signal modeling of the circuit structure is carried out,and the PI controller is selected according to the requirements of the whole machine.The simulation results are used to calculate the current sharing accuracy of each group under the condition of wide input,and the design of the current sharing control is reasonable.Finally,the hardware circuit is built for experimental testing.Firstly,the single module is tested,and the main circuit is tested with hard switch and soft switch under wide input voltage.It is concluded that the switching loss can be reduced under soft switch condition.The test of efficiency under wide input voltage shows that the hard switching state has not reached the design target.Under the condition of soft switching,the design can meet the design requirements.The efficiency decreases with the increase of voltage and the same as that of simulation analysis.The parallel test of three single power sources is carried out,and the current sharing accuracy is achieved by designing the current sharing regulation under wide input voltage.At the same time,the efficiency of the whole machine is tested by wide input,and its efficiency reaches the design target.According to the overall structure of the project and the subsequent DC-AC part,the shell of the hardware part is designed and the placement method is reasonably designed to meet the requirements of later dismantling and replacement.This paper designs according to the index of a scientific research project,and finally the DC-DC part is completed smoothly.The experimental results meet the requirements of wide input,high power and high efficiency.The soft-switching technology and digital current sharing technology used in the experiment process will have reference value for the design of aeronautical static inverter.