Effects of Post-γ Irradiation on Voltage Maintaining Performance of High Energy Density Capacitors

With the rapid development of the aerospace industry and nuclear technology, metallized film capacitor (MFC), as energy storage unit for pulsed power sources, begin to operate in various high-energy radiation environments. In order to ensure the working reliability of MFC, it is of great significance to study its voltage maintaining performance (VMP) and aging law after irradiation. In this paper, metallized polypropylene (PP) film capacitors (MPPFC) are used as the research object to analyze the irradiation reaction mechanism of polypropylene, and the effect of irradiation dose on the capacitance, dielectric loss and VMP of MPPFC under aerobic conditions is studied. The results show that there is a critical value of 100 kGy for the effect of irradiation dose on MPPFC. When the irradiation dose is less than 100 kGy, the capacitance and dielectric loss of MPPFC remain almost unchanged, and the voltage drop increases with the dose as a power function. When the irradiation dose reached 500 kGy, the macromolecules in PP film were completely cleaved, and the voltage drop of the MPPFC increased from 1.62% to 2.96% without irradiation within 10 s. In order to ensure the energy output efficiency of the power supply, the irradiation dose of MPPFC should be controlled not to exceed 5 kGy. At this time, the voltage drop of the MPPFC within 10 s is 2.30%, and the output efficiency is 95.41%. This paper serves to provide a certain basis for the application of MPPFC in irradiation environment.