Patent ID: 7407025

Claim:
An automobile power unit comprising: an engine; a motor that transmits a dynamic force to the engine and starts the engine, and that receives a dynamic force of the engine during rotation of the engine and generates a power; a power conversion circuit that has at least two DC voltage input/output terminals and transmits a power to the motor; a battery that is connected to the power conversion circuit; an energy storage source that is connected in series to the battery and stores energy; and a DC/DC converter that is composed of at least two switching elements, that charges the energy storage source by boosting a voltage of the energy storage source, and that recovers energy in the energy storage source to the battery by lowering a voltage of the energy storage source, wherein the switching elements of the DC/DC converter connect a high-voltage-side of the DC voltage input/output terminal of the power conversion circuit to a high-voltage-side terminal of the battery; wherein when the motor receives a dynamic force of the engine, generates a power, and charges the battery through the power conversion circuit and the DC/DC converter, the switching elements provided in the DC/DC converter are constantly turned on; and wherein after the engine has been started by the motor and before the power generation is carried out, the DC/DC converter operates the energy storage source in a voltage-lowerihg manner and recovers energy stored in the energy storage source to the battery.