High-Voltage Cryo-Power Inverter

The new concept of Cryogenic Power Conversion (CPC) using low temperature operated semiconductor devices and components promises higher efficiencies, drastic size, weight and cost reductions for certain suitable military and commercial applications. ThisSBIR proposes to expand the CPC-concept to the high-voltage (3-9 kV) and megawatt domain with the design and demonstration of a high-voltage cryo-cooled inverter for incorporation into DE weapon systems on missiles and tactical aircraft. It will beimplemented using new commercially available high-power devices (HV-IGBTs, IGCTs, MTOs, or IEGTs). As part of this project new circuits as well as other necessary components (inductors, transformers, capacitors) will be developed and evaluated atcryogenic temperatures (77K-200K). In Phase I a multi-kilovolt prototype inverter will be designed, assembled and tested. It is expected that higher output levels, reduced switching losses, higher power density, better thermal management, longerlifetimes, and improved reliability can be demonstrated through operation at the temperature of liquid nitrogen (77 K) or higher. Based on the Phase I prototypes and results higher voltage inverters will be developed in Phase II to address specificneeds of BMDO. Cryo-cooled coaxial or transmission line transformers using ferrite toroids provide the required higher voltages (>10 kV). Possible commercial applications of the Cryo-Inverters employing IGBTs, MTOs and/or IGCTs include solid-statetransformers, motor drives, up/down converters, adjustable speed drives (ASD), multi-phase inverters, etc., in the multi-megawatt range, especially for use in vehicles (ships, missiles, airplanes, buses, locomotives,etc.) where small size and weight areimportant.