Alternative Power Sources

This project will develop fully functional prototypes of a battery-free portable power source that can be deployed in remote, unattended locations. The power source will provide up to five watt-hours per day under extreme weather conditions for a minimum of four years without maintenance. The design relies on solar energy, and uses ultracapacitors for energy storage. A modular interconnection permits scale-up to 10 W-hr/day, 25 W-hr/day, or more by direct interconnection of multiple units. The design applies power electronic circuits and nonlinear controls to draw maximum solar power, interact with energy storage, regulate the output voltage, and manage fault conditions. Ultracapacitors will be tested to ensure that lifetime improvements from voltage derating will offset lifetime reductions from extreme temperatures. The project plan involves construction and test of initial prototypes to complete and validate the design. Following this, and the completion of package designs, a second prototype version will be constructed for initial in situ field tests. Initial field test results will be used to adjust designs for complete, field-ready prototypes. An approximate size of 12" x 12" x 3" is anticipated for final units, based on silicon solar cells. Smaller sizes are supported by advanced triple-junction compound solar cells.