A Systems Approach for a Stand-Alone Residential Fuel Cell Power Inverter Design

Analysis of an experimentally measured daily load profile reveals that the residential power demand has a high percentage of low power duration over a day. In a stand-alone residential fuel cell power system, the power inverter designed for the peak power requirement will be operating at light loads, where its efficiency is lower, most of the time. Thus, improving the light-load efficiency will provide considerable hydrogen (energy) savings for the stand-alone residential power system. A solution to improve the power inverter efficiency at light loads is proposed. Both simulation and experimental results are given. Results show that the light-load efficiency can be improved by employing and uniquely controlling a parallel IGBT-MOSFET switch combination in a half-bridge inverter topology. It is also shown that substantial savings on hydrogen usage can be realized through the use of new inverter design in stand-alone operations.