Titles:

• Development of a 1 kW, 200° C Mapham Inverter Utilizing High Temperature Components  October 1997
   
• Operational Characteristics of a 200° C LC Parallel Resonant Circuit  October 1995
   
• Effects of Thermal and Electrical Stressing on the Breakdown Behavior of Space Wiring  June 1995
   
• High Temperature Polymer Film and Ceramic Capacitors

Hammoud, A., Gerber, S., Baumann, E., Overton, E., Myers, I., and Bercaw, R., "Development of a 1 kW, 200° C Mapham Inverter Utilizing High Temperature Components", prepared for the Conference on Electrical Insulation and Dielectric Phenomena sponsored by the IEEE Dielectrics and Electrical Insulation Society, Minneapolis, Minnesota, October 19-22, 1997, NASA TM-107537.

Electronic systems and components are often exposed to high temperature environment in space-based applications, nuclear power, and geothermal energy extraction fields. A key requirement for these systems is, therefore, to withstand the high temperature exposure while maintaining efficient and reliable operation. Efforts were taken to design and develop a high temperature power inverter capable of 200° C operation. In this work, a 1 kW, 20 mHz Mapham inverter was designed and built utilizing components developed for high temperature operation. These components, which included capacitors, inductors, transformers, were developed at 200° C. The inverter system, excluding its input, control, and logic circuitries, was characterized at temperatures from ambient to 200° C at 0%, 50%, and 100% resistive loading. With an applied input voltage of 75 VDC, the inverter produced an output of 250 VAC. The results obtained, which have indicated good operational characteristics of the inverter up to 200° C, are presented and discussed.

Baumann, E. D. and Hammoud, A. N., "Operational Characteristics of a 200° C LC Parallel Resonant Circuit", prepared for the 1995 Conference on Electrical Insulation and Dielectric Phenomena sponsored by the IEEE Dielectrics and Electrical Insulation Society, Virginia Beach, Virginia, October 22-25, 1995, NASA TM-106983.

Research efforts are currently underway at the NASA Glenn Research Center to design and demonstrate an inverter capable of operating with a baseplate temperature of 200° C. In support of this project, various electrical components including capacitors, inductors, transformers, cables, and semiconductor switches are being developed or evaluated for integration into the inverter. In this work, a parallel LC resonant circuit was constructed and evaluated under simultaneous electrical and thermal stressing. The tests were performed in the temperature range of 25° C to 200° C with an applied voltage of up to 90V, 20 kHz. The individual components were comprised of high temperature film capacitors and powder core inductors developed in-house. The circuit was characterized in terms of the component currents and case temperatures as well as frequency of resonance as a function of applied bias and temperature. The results obtained, which have indicated good functional stability up to 200° C, are presented and discussed.

Several failures in the electrical wiring systems of many aircraft and space vehicles have been attributed to arc tracking and damaged insulation. In some instances, these failures proved to be very costly as they have led to the loss of many aircraft and imperilment of space missions. Efforts are currently underway to develop lightweight, reliable, and arc track resistant wiring for aerospace applications. In this work, six wiring constructions were evaluated in terms of their breakdown behavior as a function of temperature. These hybrid constructions employed insulation consisting of Kapton, Teflon, and cross-linked Tefzel. The properties investigated included the 400 Hz AC dielectric strength at ambient and 200° C, and the lifetime at high temperature with an applied bias of 40, 60, and 80% of breakdown voltage level. The results obtained are discussed, and conclusions are made concerning the suitability of the wiring constructions investigated for aerospace applications.

Mandelcorn, L., Gurkovich, S. R., Radford, K. C., Hammoud, A., Overton, E., and Bauman, E., "High Temperature Polymer Film and Ceramic Capacitors".

This is an update on high temperature power electronics capacitor developments at Northrop Grumman and NASA Glenn for operation at 200° C Hz and 20 kHz voltage stresses at 225° C. Ceramic capacitors, AVX-NPO1COG, sustained aging at 200° C, with and without 500 Vdc, without impairing their electrical properties. A proprietary Northrop Grumman ceramic sowed promise for capacitor dielectric operation at 400° C.
 

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Last Updated: 04/07/2008