Abstract: A series circuit of a first main transistor 4 and a first main diode 6 is connected across a DC input voltage source 1, and a filter capacitor 13 and a series circuit of a second main diode 12 and a second main transistor 8 are connected in parallel with the output load side. A filter reactor 7 is connected between the juncture of the first main transistor 4 and the first main diode 6 in the series circuit and the juncture between the second main diode 12 and the second main transistor 8 in the series circuit. Resonant capacitors 5 and 9 in effect are connected across the collector-emitter path of the first and second main transistors 4 and 8, respectively. In operations other than that with small load current, when the first and second main transistors 4 and 8 are turned off, the collector currents therefrom are caused to flow to the resonant capacitors 5 and 9, respectively, thus obtaining soft switching.

Abstract: A series circuit of a first main transistor 4 and a first main diode 6 is connected across a DC input voltage source 1, and a filter capacitor 13 and a series circuit of a second main diode 12 and a second main transistor 8 are connected in parallel with the output load side. A filter reactor 7 is connected between the juncture of the first main transistor 4 and the first main diode 6 in the series circuit and the juncture between the second main diode 12 and the second main transistor 8 in the series circuit. Resonant capacitors 5 and 9 in effect are connected across the collector-emitter path of the first and second main transistors 4 and 8, respectively. In operations other than that with small load current, when the first and second main transistors 4 and 8 are turned off, the collector currents therefrom are caused to flow to the resonant capacitors 5 and 9, respectively, thus obtaining soft switching.

Abstract: In a replenishing power supply system, a plurality of DC/DC converters (5, 6 and 7) are connected in parallel, and the number of DC/DC converters (5, 6 and 7) to be started is changed based on the amounts of electric power used by auxiliary loads (11 and 12). Moreover, the DC/DC converters (5, 6 and 7) are started in order based on a predetermined sequence.

Abstract: In a replenishing power supply system, a plurality of DC/DC converters (5, 6 and 7) are connected in parallel, and the number of DC/DC converters (5, 6 and 7) to be started is changed based on the amounts of electric power used by auxiliary loads (11 and 12). Moreover, the DC/DC converters (5, 6 and 7) are started in order based on a predetermined sequence.

Abstract: A fuel cell power plant (1) and a rechargeable battery (2) are connected in parallel to an electric motor (3) of a fuel cell powered vehicle, and the output voltage of the fuel cell power plant (1) is regulated by a converter (4). A temperature sensor (5) detects the temperature of the electric motor (3), and a controller (6) controlling the output voltage of the converter (4) to a predetermined high voltage value when the temperature of the electric motor (3) is greater than a predetermined temperature, thereby preventing the excessive rise of the temperature of the electric motor (3).

Abstract: A fuel cell power plant (1) and a rechargeable battery (2) are connected in parallel to an electric motor (3) of a fuel cell powered vehicle, and the output voltage of the fuel cell power plant (1) is regulated by a converter (4). A temperature sensor (5) detects the temperature of the electric motor (3), and a controller (6) controlling the output voltage of the converter (4) to a predetermined high voltage value when the temperature of the electric motor (3) is greater than a predetermined temperature, thereby preventing the excessive rise of the temperature of the electric motor (3).