Patent ID: 7301247

Claim:
A power supply device incorporated in a vehicle driven by an internal combustion engine comprising: a first power supply system that uses a first generation coil provided in a generator driven by said internal combustion engine as a power source to supply DC power to a power supply line that provides a power supply voltage to an electrical load or electrical loads provided in the vehicle; a second power supply system having a DC power supply unit that uses a second generation coil provided in said generator as a power source to generate a DC output, and an inverter that converts the output of said DC power supply unit into an AC output at a commercial frequency; a transfer switch that switches a supply target of an output of said second power supply system, so as to supply the output of said second power supply system across output terminals to which an external load is connected when the external load is driven, and supply power from said second power supply system to said power supply line when said external load is not driven; and inverter control means for assistance for controlling switch elements that constitute said inverter, so as to operate said inverter as a DC-DC converter when said transfer switch is switched so as to supply the power from said second power supply system to said power supply line, and so as to supply a DC output having a voltage value equal to or close to a rated value of an output voltage of said first power supply system from said second power supply system to said power supply line in order to assist the first power supply system.