Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. FIG. 1 illustrates a configuration, view of an electrical system of a vehicle, including an electric power conversion system 10 according to the present embodiment. The alternate long and short dashed lines in FIG. 1 represent signal lines. In FIG. 1, for the sake of easy understanding, part of components not associated with electric power conversion are not shown in the drawing.

Overall Configuration

The electric power conversion system 10 includes a first battery B1, a second battery B2, an electric power converter 11 (converter) and a CNV controller 13 that controls the electric power converter 11. The electric power conversion system 10 is mounted on a vehicle, such as a hybrid vehicle and an electric vehicle. Other than the electric power conversion system 10, an inverter 18, a rotary electric machine 20 and a controller 22 are mounted on the vehicle.

As shown in FIG. 1, each of the first battery B1 and the second battery B2 is separately connected to the electric power converter 11. The electric power converter 11 steps up direct-current voltages VB1, VB2 from the first battery B1 and the second battery B2, and outputs the stepped-up direct-current voltages VB1, VB2 to the inverter 18.