Provided is a received power conversion device for a resonant wireless charging system, including a wireless power receiver for receiving wireless power from a wireless power transmission device, a rectifier for rectifying power in an Alternating Current (AC) form received in the wireless power receiver into a Direct Current (DC), a free-wheeling switching unit for switching according to a switching control signal to form a path for free-wheeling the power in the AC form, a feedback circuit fed back with an output signal of a corresponding power conversion device to detect a level of the output signal, and a controller for controlling switching of the free-wheeling switching unit according to the output level detected by the feedback circuit.