Power conversion system

A power conversion system comprising:

• a transformer configured to step down power from an overhead wire;
• an alternating current to direct current conversion circuit configured to convert alternating current power supplied via a secondary winding of the transformer into direct current power;
• a step-down chopper circuit connected to the alternating current to direct current conversion circuit, the step-down chopper circuit being configured to step down a voltage of the direct current power produced through conversion by the alternating current to direct current conversion circuit;
• a first power conversion unit for alternating current loads, the first power conversion unit being connected to the step-down chopper circuit, the first power conversion unit configured to convert the direct current power stepped down by the step-down chopper circuit into alternating current power for driving an alternating current load mounted in an electric vehicle and to supply the alternating current power to the alternating current load;
• a voltage detector connected between the step-down chopper circuit and the alternating current to direct current conversion circuit, the voltage detector configured to detect a voltage of a direct current link between the step-down chopper circuit first power conversion unit for alternating current loads;
• a second power conversion unit for direct current loads, the second power conversion unit being connected to the step-down chopper circuit, the second power conversion unit being configured to convert the direct current power stepped down by the step-down chopper circuit into direct current power for driving a direct current load mounted in the electric vehicle and to supply the direct current power to the direct current load;
• and
• a control unit connected to the alternating current to direct current conversion circuit and connected to the step-down chopper circuit ,the control unit being configured to control the alternating current to direct current conversion circuit and the step-down chopper circuit such that the voltage of the direct current link detected by the voltage detector approaches a reference voltage.