IAP RESEARCH INC DAYTON OH, Johnson, Donald E., Barber, John P., Laquer, Henry L., Portnoy, William M., IAP RESEARCH INC DAYTON OH, Johnson, Donald E., Barber, John P., Laquer, Henry L., and Portnoy, William M.
Cryogenically cooling power conditioning systems in space-based multi-megawatt power systems will reduce system mass, volume, and complexity. Cryogenically cooled generators and power transmission systems for space are already under development. These generators and transmission busses are considerably lighter and more compact than comparable room temperature components. Most of the mass and volume savings results from the greatly increased electrical conductivity of metals cooled to cryogenic temperatures. Power conditioning components do include metal conductors but also use insulators, semiconductors, and resistors. The behavior of these materials, and thus power conditioning components, is more complex at low temperatures than metals. There is presently no technical data base we can use to predict the behavior of power conditioning systems. It is difficult to predict the mass savings or penalty we must incur if we choose to operate the power conditioning system at cryogenic temperatures. This report describes a 230 manhour study we undertook to answer those three questions. We reviewed the state of the art in cryogenically cooling typical converter components and materials. We reviewed the properties and hazards of cooling with supercritical hydrogen. Finally, we assessed the ability of WRDC to use small quantities of hydrogen for component development tests. We concluded that almost all power conditioning components can be operated at cryogenic temperatures. We expect cryogenic operation to cause a significant mass and volume reduction for many of the key components. Finally, considerable development work is required before we are ready to build a complete power conditioning system.