Abstract: In order to reduce the size of an isolation transformer, the present invention provides a power conversion device including: a first inverter unit for obtaining a DC input and giving a high frequency output; an LLC transformer for converting the voltage of the high frequency output of the first inverter unit; a rectifier unit for DC-converting the voltage of the output of the LLC transformer; a second inverter unit for converting the DC output of the rectifier unit into AC; and a control circuit for obtaining the gate power of a semiconductor device configuring the second inverter unit through a power supply transformer for the control circuit that is connected in parallel to the secondary circuit of the LLC transformer.