A control strategy for high-quality electric energy supply system equipped with fuel cells and ultracapacitors

The paper focuses on experimental and numerical results of a research program addressed to study the possibility of coupling fuel cell source with ultracapacitor storage device. The paper, starting from the experimental tests done on a fuel cell source, useful to set up subsystem analytical models, examines the energy flow among the electrical sources. It is defined a control strategy suitable to manage the power flow for load variations. In particular, are considered the possibilities that: i) the fuel cell is able to furnish power to the load and the ultracapacitor device acts as active filter for stabilizing dc bus voltage; ii) the fuel cell is not able to feed the whole power demand and the ultracapacitor device compensates the difference between maximum fuel cell power and load required power.