New airborne and mobile military systems will require megawatts of very high-voltage, electrical power delivered from very lightweight power sources. Traditional airborne power system equipment will simply not be able to produce megawatts of electrical power delivered at voltages up to 90,000 volts DC. Novel lightweight, high frequency, high-voltage transformers with integral, high-voltage, power conditioning will be required for the success for these new missions. In this Phase II program, we will build and test a lightweight, four-megawatt, high-voltage transformer, with integral power conditioning that will be specifically designed as a proof-of-principle power system demonstrator for several airborne and mobile power systems. This 22 month program will deliver a fully functional, high-voltage transformer/power conditioning module (using either conventional or novel cryogenic technology) that is designed to interface with both a cryogenic generator being built in a companion, Phase II SBIR and also a high-voltage load being developed for the HEX system. These two carefully coordinated programs will combine to produce a complete multi-megawatt, high-voltage power system specifically designed for a wide range of airborne applications and will offer a 2:1 weight reduction over conventional technology