POWER CONVERSION SYSTEM

A DC/DC converter (1) includes a power conversion unit (3) for converting input voltage to required voltage, a first control unit (4) for driving the power conversion unit (3), a power supply device (5) which supplies power to the first control unit (4) and uses an output of the DC/DC converter (1) or a battery (100) as a power supply source, and a power supply function (6) for controlling supply of power to the power supply device (5). The power supply function (6) is controlled with respect to supply of power, by a second control unit (10) of a power conversion device (2), during a standby state of the DC/DC converter (1) .