Flatness based control of an isolated three-port bidirectional DC-DC converter for a fuel cell hybrid source

A flatness based controller for a hybrid source system, which is a fuel cell (FC) and supercapacitor (SC), is presented. The FC is used as a main power source. The SC is employed as auxiliary source to deal with the slow transient response of FC. An isolated three-port bidirectional full-bridge dc-dc converter is utilized to transfer energy bidirectionally between the load and the auxiliary source. The FC current-changing rate limitation is taken into account. The hybrid source including the proposed controller is validated through simulation and experimental results.