DC-DC converter suitable for medium voltage distribution network

Abstract

The invention discloses a DC-DC converter suitable for a medium voltage distribution network, and belongs to the field of medium voltage DC distribution networks. The converter shown comprises: a module chain bridge arm, a resonance module, an isolation transformer, and a rectifier module; the module chain bridge arm is connected with a power supply on a medium voltage distribution network side for improving the voltage of the power supply on the medium voltage distribution network side; a first connecting end of the resonance module is connected with a midpoint of the module chain bridge arm,a second connecting end of the resonance module is connected with the midpoint of the power supply on the medium voltage distribution network side, and a third connecting end of the resonance moduleis connected with a primary side of the isolation transformer; and a secondary side of the isolation transformer is connected with the rectifier module. The DC-DC converter disclosed by the inventionutilizes the modular multilevel technology to improve the voltage level on the input side of the converter, so that the new topology is suitable for medium voltage and even high voltage occasions, andmeanwhile, a transformer with a high transformation ratio is used to distribute power to users, so that the cost is reduced; and the DC-DC converter disclosed by the invention can achieve zero voltage turn-on of all switches and zero current turn-off of diodes within a full load range, thereby greatly reducing the switching loss and improving the efficiency of the entire converter.

Description

technical field [0001] The invention belongs to the field of medium-voltage direct current distribution network, and more specifically relates to a DC-DC converter suitable for medium-voltage distribution network. Background technique [0002] With the large-scale application of renewable energy, my country's coal-based energy structure has undergone major changes, and society's demand for fossil energy has been greatly reduced. However, the access to high-throughput renewable energy has changed the power structure of the traditional power grid and caused many technical problems. Therefore, it poses severe challenges to the reliable operation of the current power system. In order to deal with the problems brought by the access of new energy sources, the economic and technical advantages of the DC grid over the traditional AC grid have attracted widespread attention from scholars at home and abroad. The DC power grid does not require reactive power compensation and power syn...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide a DC-DC converter suitable for medium-voltage distribution network, aiming to solve the problems caused by the use of DC solid-state transformer and low transformation ratio in the existing DC distribution network distribution method. A bipolar structure combined with a DC converter, but there are problems of low power distribution efficiency and high cost

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