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

Abstract

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.

Description

technical field [0001] The invention mainly relates to the power supply field of electric traction technology, in particular to a dual-current traction power supply system based on a modularized multilevel converter. Background technique [0002] my country's electric traction is being more widely used in the field of railway and urban rail transit because of its high efficiency, fast and energy-saving characteristics. Utilize new technologies to transform traditional industries, speed up the process of electrification of railways, and take into account the construction of subways. Consideration must be made into networks and blocks, so as to give full play to the potential of electric traction to pull more and run faster, and greatly improve the utilization rate of state-owned resources. It has become the focus of today's industry. [0003] The electric energy used by my country's electrified railway and urban rail transit is supplied by the power plant of the national pow...

AI Technical Summary

Problems solved by technology

Among them, the main junction of single-phase V / V junction transformer is relatively simple, with less equipment and less investment, but when one traction transformer fails, the other must supply power across phases, that is, both the left and right power supply arms Traction network, a switching process is required at this time, and the negative sequence impact on the power system will increase accordingly

The three-phase Yn / d11 double-winding transformer has been used in my country for a long time, and its manufacture is relatively simple and cheap. However, the capacity of the traction transformer cannot be fully utilized, the main wiring is relatively complicated, and the project investment is also large.

However, the existence of the rectifier unit increases the complexity of the traction substation, and the output characteristics of the device affect the reliability of the DC traction power supply system

In addition, the rated voltage of the DC traction motor cannot be too high due to the commutation conditions, that is, the voltage of the traction network is difficult to further increase, which requires the traction network to transmit a large amount of current to supply urban rail vehicles, which will be limited by the capacity of the backup power supply

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