Ground simulation of a hybrid power strategy using fuel cells and solar cells for high-endurance unmanned aerial vehicles

• Published in: Energy (Oxford) 2017-12, Vol.141, p.1547-1554
• Main Authors: Gang, Byeong Gyu, Kim, Hyuntak, Kwon, Sejin
• Format: Article
• Language: English
• Subjects: Batteries; Converters; Electric power; Electric power systems; Electric relays; Fatigue tests; Fuel cells; Fuel technology; Hybrid systems; Hybrid vehicles; Hydrogen generator; Hydrogen storage; Liquid fuels; Liquid sodium; Micro-processed controller; Photovoltaic cells; Power sources; Proton exchange membrane fuel cell system; Proton exchange membrane fuel cells; Simulation; Sodium; Sodium borohydride; Solar cell system; Solar cells; Solar power; Solid state physics; Solid-state relay; Unmanned aerial vehicles; Voltage converters (DC to DC)
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2017.11.104

A hybrid electric power system for high-endurance unmanned aerial vehicles is tested on the ground, alternating between fuel and solar cell power. A fuel cell system is constructed using a micro-processed controller, micro-pump, hydrogen generator using 20 wt% liquid sodium borohydride (NaBH4) solution, and proton exchange membrane fuel cell stack connected with a battery in parallel. The solar cell system consisted of a DC-DC converter, a battery, and solar modules. These two power sources are integrated via a power switching strategy using two solid-state relays connected to the controller, which turn on the fuel cell system to provide the power necessary to satisfy the load while the solar power system is on standby, charging the solar cell battery, or vice versa. In this way, not only is the operational period increased with high reliability by making one power source be on standby while the other is in use, but also the control logic of the system is simplified. Moreover, the fuel cell power could be adjusted by flowing different amounts of NaBH4 solutions using a controller to save liquid fuel, thereby extending the operational time. •A hybrid power system integrating fuel and solar cells was evaluated.•A power management method using solid-state relays was validated.•A solar module with a supportive battery proved effective as an independent power source.