| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress switching loss as much as possible in a voltage step-up converter such as a DC-DC converter for stepping up output voltage from a DC power supply unit such as a fuel cell. <P>SOLUTION: The fuel cell system is provided with: a voltage step-up section including a main voltage step-up section for causing a main switch means to perform a switching operation for a main coil connected to a terminal of a high potential side of the fuel cell so that an output voltage of the fuel cell is stepped up, and an auxiliary voltage step-up section having a snubber capacitor connected in parallel to the main switch means and capable of adjusting a voltage applied to the main switch means, and adjusting an applied voltage of the snubber capacitor in response to the voltage step-up operation by the main voltage step-up section; a voltage step-up control means for stepping up the output voltage of the fuel cell via the voltage step-up section and applying the stepped-up voltage to a load; and a voltage step-up ratio adjusting means for adjusting the exit voltage of the voltage-step up section so that a ratio of the exit voltage of the voltage step-up section to the output voltage of the fuel cell can exceed a predetermined voltage step-up ratio when applying the stepped-up voltage to the load. <P>COPYRIGHT: (C)2009,JPO&INPIT |
