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Emerging power electronics in a broad range of military, aerospace, hybrid vehicle, renewable energy and drilling applications rely on advances in dielectric materials for capacitors. Compact capacitors possessing low dielectric loss and high operating temperature capability are needed for power conditioning in advanced converter and inverter designs for these applications. Wound film capacitors represent the preferred capacitor technology but are limited by low operating temperature capabilities, < 150°C, and low volumetric efficiency, capacitance per unit volume less than 1.0 μF/cc. TPL is developing processes and manufacturing techniques for fabrication of advanced capacitor films comprised of high temperature polymers modified with ceramic nanoparticles. The selected polymers enable high temperature operation and the ceramic nanoparticles enhance volumetric efficiency by increasing the dielectric constant. The fabricated films are adaptable to conventional wound film capacitor construction methodologies. This paper provides an overview of TPL's experience to-date with a film dielectric material system comprised of fluorenone polyester polymer and titanate nanoparticle filler. The fluorenone polyester polymer was selected to provide a stable operating temperature of at least 200°C, while the addition of the titanate powder increases the dielectric constant and, in turn, the volumetric efficiency of wound film capacitors constructed with this film system. Status and ongoing capacitor development issues are provided relative to the intended high temperature power conditioning applications.

Film capacitors that perform well at temperatures exceeding 150°C and have energy densities in excess of 1 J/cm3 are an enabling technology for many applications in automotive, geophysical exploration, aerospace, and the military. To address this need Faradox Energy Storage, Inc. has produced and is testing high temperature film capacitors fabricated using amorphous oxides (OxFilm™) as the dielectric material. The capacitors are made by depositing thin films of an oxide dielectric on both sides of a double metalized polyimide substrate to form dielectric-coated electrodes. Currently Faradox is producing 2″ long, 1/4″ diameter 2 uF, 100 VDC capacitors using silicon dioxide as the dielectric material. In this paper we present test data demonstrating that OxFilm capacitors have relatively stable properties over a wide temperature range. Measurements include capacitor testing at different 3rd Party test facilities and internal testing using a variety of test conditions including:Life testing at 200 and 250°C for over 1000 hours with measurements of capacitance, leakage, dF and ESR.Capacitance versus voltage, temperature and frequencyImpedance, ESR, and dF versus frequency and temperature and voltageData will also be presented that show these capacitors can be cycled between 0°C and 200°C without degrading their performance. Work is ongoing to obtain additional test data with more statistically significant numbers of capacitors.