DC-DC Converter for Regenerative Fuel Cell / Battery Hybrid Systems

Satellite platforms, high altitude long endurance (HALE) aircraft, and remote terrestrial telecommunications stations require highly reliable energy production and storage systems to maximize payload power and performance. The regenerative fuel cell (RFC) system, in hybrid configuration with a battery pack or ultracapacitor bank, can provide a 25:1 peak to base load power delivery ratio. However, this hybrid system requires a DC-DC converter from the energy source (solar array) to the RFC electrolyzer and payload, and a specialized bi-directional DC-DC converter to protect the fuel cell, control the flow of power to and from the battery or ultracapacitor, and stabilize the DC bus. The proposed Phase II effort will develop a combination multi-directional DC-DC converter that will satisfy these complex requirements. The DC-DC converter must have a high conversion efficiency, low weight, low volume and sophisticated control scheme to regulate the system under many circumstances. AeroVironment has developed the high altitude RFC system for NASA’s ERAST program and conducted many other fuel cell integration projects. We have also developed many specialized DC-DC converters. By demonstrating feasibility, we will assist the Air Force to develop efficient energy production and storage systems for satellites and HALEs for station-keeping and powering large payloads.