DIRECT TO PHASE II- Electrical Capacitors for High-Temperature Power Conversion

RT&L FOCUS AREA(S): General Warfighting Requirements (GWR) TECHNOLOGY AREA(S): Electronics OBJECTIVE: Identify and demonstrate that advances in polymeric (or other film materials) dielectrics can be exploited in high temperature (150 C 200 C), compact, long life, highly reliable, electrical power capacitors in aircraft. DESCRIPTION: Electrification of naval aerospace platforms continues. Aircraft designers are being challenged to supply more power to new classes of nonlinear and constant power loads. In response to these new loads, the electrical power generation/distribution system, as well as the electrical loads themselves, are being required to minimize losses, while rejecting heat at high temperatures and maintaining conversion equipment reliability. A well-established design practice indicates component reliability of their insulation systems can be increased by 2 times for every 100 C the operating temperature is lowered below the design maximum temperature. While new classes of power semiconductor switching devices based on wide-bandgap materials (i.e., SiC and GaN) are maturing with advertised operating junction temperatures up to 200 C, the development of high-temperature, reliable capacitors have not followed suit. To achieve reliability, today's power conversion capacitors are operated at temperatures of ~150 C thus limiting converter/inverter fluid-in temperatures at/or below 75 C. Capacitors with operating temperatures in the range of -40 C to 150 C, with a maximum temperature of 200 C is the program's primary goal. There are additional characteristics which are important for aircraft including: operation at altitude (up to 70,000 ft (21,336 m)), weight and volume comparable to state-of-the-art aerospace capacitors, equivalent series resistance (< 2 MO goal), and low inductance (< 50 nH goal). In addition, the capacitors are needed for both DC link applications as well as for AC filters. Capacitors with operating capabilities in the temperatures stated above will enable converter/inverter fluid-in cooling temperatures of 100 C or higher. The Navy requires representative high-temperature capacitors for aircraft electrical DC link and filter applications with the following characteristics that are important for aircraft including, but not limited to: DC Voltage Rating (Nominal): 600 Vdc (Target), 500 Vdc Capacitance: 300 uF 5.0% (1 kHz 40 kHz & @ 150 C) Operation Temperature: -55 C (Start-up) -40 C +150 C Maximum Storage Temperature: 175 C ESR: < 1 MO (1 kHz 40 kHz at 150 C) ESL: < 1 nH per mm of lead spacing Dissipation Factor (DF): 65,000 ft (19,812 m) Insulation Resistance: 10 MO between positive terminal or negative terminal and case Dimension (Target):