AC and DC output fuel cell hybrid system: Design, building and testing

This paper develops, builds and tests a hybrid system made up of a fuel cell stack and a battery bank. The hybrid system has been built to supply DC and AC outputs. Voltage levels established on electrical interconnection points are achieved with several power conditioning stages controlled by pulse width modulation (PWM) and gain scheduling techniques. This work means a contribution to few works related to renewable energy distributed generation systems which integrate gain scheduling control techniques. Applications of the developed hybrid system can be extended from auxiliary power units (APU) in cars, buses or locomotives to uninterruptible power systems (UPS) in hospitals, nursing-homes, hotels, office buildings or schools.