  In this manuscript, the performance of an ultracapacitor fuel cell in grid
connected mode is investigated. Voltage regulation to the ultracapacitor was
achieved with a three level bidirectional DC-DC converter while also achieving
power flow from the grid to the ultra-capacitor via the bidirectional
converter. The choice of a bidirectional three level converter for voltage
regulation is based on its inherently high efficiency, low harmonic profile and
compact size. Using the model equations of the converter and grid connected
inverter derived using the switching function approach, the grid's direct and
quadrature axes modulation indices, Md and Mq, respectively were simulated in
Matlab for both lagging and leading power factors. Moreover, the values of Md
and Mq were exploited in a PLECS based simulation of the proposed model to
determine the effect of power factor correction on the current and power
injection to grid
