Four-Quadrant GaN-Based Battery Isolator Unit

Military ground vehicles currently use two battery banks, one for powering loads and one for engine starting, connected together through battery-isolating diodes, which are heavy, inefficient, and failure prone. A more intelligent approach to battery isolation is accomplished by adopting smart power electronics and digital controls. With these goals in mind, during Phase I Mainstream designed, built, and tested (up to 125% die current loading) a Gallium Nitride (GaN)-based battery isolator unit (BIU), achieving a Technology Readiness Level (TRL) of 4. The full 500 Apk BIU is modular, scalable, and at worst case loading, has an efficiency of 96%, occupies a volume of 756 in3 and weighs 28 lbs, or about 2/3 the size and 1/3 the weight of a 12 V vehicle battery. Building on the highly successful Phase I Base, during Phase II we will perform two rounds of BIU builds for experimental testing. Conformance to applicable military EMI, power quality, and environmental requirements will be verified. At the completion of Phase II the GaN BIU will achieve a TRL of 6, with a system prototype validated in a relevant environment. We anticipate rapidly transitioning the proposed technology to a production-ready unit early in Phase III.