Research on the Influence of Safety Film on the Thermal Field Distribution of Metallized Film Capacitors

Metallized film capacitors are widely applied in power electronics devices due to their large capacitance and high power density, such as support capacitors for flexible DC converter valves. In this paper, thermal resistance of the T-shaped safety film and the diamond-shaped safety film are simulated and calculated, and the power density of the film is calculated according to the equivalent resistance. The overall temperature rise of the capacitor is simulated and analyzed. Simulation results show that the ordinary metallized film has the lowest thermal resistance; the thermal resistance and equivalent resistance of the safety film mainly depend on the effective cross-sectional area of fuse. When the effective cross-sectional area is increased, the thermal resistance will become smaller, improving the heat dissipation capacity of the capacitor. The temperature rise of T-type safety film capacitors is the most serious, which is 15 K higher than that of ordinary metallized films.