Power electronics in harsh environments

The environmental temperature in many NASA missions, such as deep space probes and outer planetary exploration, is significantly below the range for which conventional commercial-off-the-shelf electronics is designed. Presently, spacecraft operating in the cold environment of such deep space missions carry a large number of radioisotope or other heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 /spl deg/C. Electronic devices and circuits capable of operation at cryogenic temperatures -does not only tolerate the harsh environment of deep space but also reduces system size and weight by eliminating or reducing the heating units and their associate structures; thereby reducing system development cost as well as launch costs . This improvement results from better behavior in the electrical and thermal properties of some semiconductor and dielectric materials at low temperatures. An on-going research and development program on low temperature electronics at the NASA Glenn Research Center focuses on the development of efficient electrical systems and circuits capable of surviving and exploiting the advantages of low temperature environments. In this paper, the performance of some power electronic components and circuits was investigated under low temperature. These include semiconductor switches, inductors, capacitors, pulse-width-modulation (PWM) controllers, and advanced commercial DC/DC converter modules. Different properties were determined as a function of temperature in the range of 20 /spl deg/C to -196 /spl deg/C, at various current and voltages levels. The experimental procedures along with the experimental results are presented and discussed.