Abstract: A power control device comprising: a step-down converter configured to step down DC power supplied from a DC power source; a temperature sensor configured to detect a temperature of the step-down converter or a temperature correlated therewith; and a control device configured to control an operation of the step-down converter based on a target value for an output voltage of the step-down converter. The control device is configured to change the target value between at least two values in response to the temperature detected by the temperature sensor.

Abstract: A power conversion device is configured to reduce the number of temperature sensors that are to be mounted to the power conversion device. The power conversion device has a plurality of reactors and a cooling flow path in which the plurality of reactors are placed sequentially. The power conversion device is configured to convert electric power from a power storage device. The power conversion device further includes a temperature sensor that is mounted to only part of reactors including a reactor having a highest thermal resistance out of the plurality of reactors. A reactor having the higher thermal resistance has a larger degree of a variation in temperature than the degree of a variation in temperature of a reactor having the lower thermal resistance. Accordingly, the configuration of detecting the temperature of the reactor having the higher thermal resistance increases the sensitivity of control and implements the more appropriate control.