A power conversion device is disclosed herein. The power conversion device includes an AC-DC conversion unit, a switching unit and a bypass circuit. The AC-DC conversion unit is configured to receive an AC input voltage via a power input terminal, and output a DC output voltage to a power output terminal according to the AC input voltage. The switching unit is configured to be switched off according to the AC input voltage received from the power input terminal, and to be switched on according to a DC input voltage received from the power input terminal. The bypass circuit is configured to receive the DC input voltage via the switching unit, and output the DC output voltage to the power output terminal according to the DC input voltage.