Simulation And Research Of Lighting Protection On Power Supply System For Flight Test Of C919 Airplane

Reliable power supply system for flight test is the key to ensure the success of flight test.According to the airworthiness requirement,power supply system for flight test should follow electromagnetic and lightning interference requirements.By laboratory test,it is confirmed that shielding and installing traps can solve the electromagnetic interference problem effectively,but the lightning interference test is difficult to carry out due to limited conditions,thus the lightning protection and its related technologies are studied in this paper.Firstly,according to airworthiness requirement,the external and internal lightning environment of the aircraft and the simulation waveform of the lightning environment are introduced,thus the lightning protection compliance verification process and the test waveform which suitable for lightning environment are determined.Secondly,C919 aircraft model and the power supply system and its cable model are built using the electromagnetic simulation software CST platform.Based on the theory of transmission line matrix,the surface current distribution,magnetic field intensity and coupling condition of the flight test power supply system are simulated under different pulse injection paths.According to the cable coupling condition,the lightning test level and the protection design level are determined.The impact current generator for the indirect lighting test of airborne equipment is designed and simulated in MATLAB software.The rationality of circuit design and parameter calculation is verified.Finally,the lightning impulse response of the rectifier circuit in the power supply system is simulated and analyzed by using the lightning impulse generated by the impact current generator.At the same time,a comparative analysis of the lightning characteristics of gas discharge tube,mental oxide varistor and transient voltage suppression diodes is conducted,and the MOV and TVS are selected for lightning protection design and simulation.Through the electromagnetic simulation and circuit simulation,the lightning environment of the power supply system is determined,the lightning impulse response of the system circuit is analyzed,and the lightning protection measures are designed and the effectiveness is verified.