Double-current system traction power supply system based on modularized multi-level current converter

A double-current system traction power supply system based on a modularized multi-level current converter comprises a step-down transformer, a high-voltage MMC rectification circuit, an inverter circuit and a step-down chopper circuit, wherein the input end of the step-down transformer is connected with a three-phase alternating current, the output end of the step-down transformer is connected with the high-voltage MMC rectification circuit, and the output end of the high-voltage MMC rectification circuit is connected with a direct current transmission cable. The input end of the step-down chopper circuit is connected with the direct current transmission cable through a second switch block, and the output end of the step-down chopper circuit is connected with a traction system through a fourth switch block. The input end of the inverter circuit is connected with the direct current transmission cable through a third switch block, and the output end of the inverter circuit is connected with the traction system through a fifth switch block. The fourth switch block is in an interlock relation with the third switch block and the fifth switch block. The double-current system traction power supply system based on the modularized multi-level current converter has the advantages of being high in function integration degree, wide in application range, good in safety, good in power supply reliability and the like.