Electrical Characteristic Study of a Hybrid PEMFC and Ultracapacitor System

This paper presents the characteristic study of a clean hybrid power supply system combining proton exchange membrane fuel cell (PEMFC) as the main power source and ultracapacitor (UC) as the energy storage unit. Unlike the conventional fuel-cell hybrid system with power conditioning unit, the study investigated the electrical characteristic of the PEMFC and UC hybrid system without dc/dc converter. As a platform to evaluate the proposed system, the fuel-cell-based electric bicycle is implemented. The platform consists of PEMFC stack, metal hydride, thermal balance system, UC, dc motor, system control and data logging unit, as well as user interface. The test results showed that the proposed architecture is functional and leads to good results. By road testing, it was verified that the PEMFC can provide the rated power to the load and that the UC can deliver the power at system startup and the peak power if needed. The road testing results showed that the design objectives are fulfilled.