Design and analysis of a direct borohydride fuel cell DC-DC converter for portable applications

Due to high power density and reactivity compared with gaseous hydrogen as the fuel, the direct borohydride fuel cell (DBFC) is becoming an emerging type of fuel cell. Electrochemistry of DBFC is described in this thesis. V–I characteristics and the equivalent circuit of DBFC are tested and analyzed. A dc-dc boost converter is designed due to the low output voltage level of DBFC. Simulation results show that the controller of the boost converter has a good stability and regulates the voltage output as desired. The compatibility between the DBFC and the boost converter is discussed. The stability of the DBFC power conditioning system including models of the DBFC and converter is verified through time domain and frequency domain tests. It is shown that the dc-dc boost converter can work under stable conditions with the DBFC acting as the power source. Transient load tests and transient response tests have been done to show the desired system performance is achieved.