Thermal stability evaluation and optimal design of polymer film capacitors for power pulse systems

Abstract

Polymer film capacitors are highly favored in pulse power systems due to their high-power densities and excellent fatigue resistance. However, thermal runaway under extreme operation conditions can severely affect the stability of dielectric capacitors, which is less well understood and managed. Here, we establish a pulse circuit model to analyze the energy dissipation of the metallized film capacitor during charging and discharging. It is found that the thermal effects of the capacitor are affected by four aspects of material property, device structure, load resistance, and operating condition. Heat generation in the pulse power capacitor is the result of the combined effects of voltage and current, with the Joule heat loss in the electrodes being the primary source. A mapping diagram is established to illustrate the relationship between peak current density, frequency, and maximum temperature. Additionally, the “Dangers Area” under extreme pulse conditions is identified and optimized. This work not only offers a general approach for studying the thermal effects in metallized film polymer capacitors, but also provides theoretical insights for the thermal management and design of pulse power capacitors in practical applications.