An electric power converter includes a chopper circuit, a DC-DC converter coupled to an output of the chopper circuit, a first transformer including a first primary coil and a first secondary coil, a second transformer including a second primary coil and a second secondary coil, a first capacitor coupled between an output of the DC-DC converter and the first primary coil, a second capacitor coupled between the output of the DC-DC converter and the second primary coil, a first rectifier circuit coupled to the first secondary coil, and a second rectifier circuit coupled to the second secondary coil. A first output voltage of the first rectifier circuit is adjusted by adjusting an output voltage of the chopper circuit, and a second output voltage of the second rectifier circuit is adjusted by adjusting a powering time during one switching period of the DC-DC converter.