High Temperature Capacitors with Minimal Derating of Operating Voltage for DC-Link Applications

Abstract:
New high temperature capacitors made with recently introduced high-heat polymer film, ELCRES(TM) HTV150, are shown to operate at higher temperatures reaching 150deg C with little derating of applied voltage. At 105deg C the operating voltage is 210V/µm; at 150deg C, the voltage is 180V/µm, or 14% derating over a broad temperature range. By comparison, the rated voltage for typical polymer film capacitors, e.g., capacitors made with polypropylene (PP) or ethylene propylene norbornene (EPN), is reduced byas much as 50% when the temperature reaches 125deg C for PP, or 135deg C for EPN. Such reduction, orvoltage derating, must be compensated for by increasing the thickness of the polymer film used in thecapacitor to maintain the voltage withstanding ability over the operating temperature range. Capacitors made with HTV150 film pass 2000-hour reliability life testing at the elevated temperaturesand rated voltage with stable capacitance, dielectric losses, and insulation resistance. Such capacitorsare well positioned for use in the AC-DC inverters in DC-link modules operating at high voltages andtemperatures reaching 150deg C for efficient operation in electric vehicle applications.