Modular multi-electric-level current converter and converter valve module unit thereof

Abstract

The invention discloses a converter valve module unit. The converter valve module unit comprises at least one direct-current supporting capacitor, an equalizing resistor, four power semiconductor switch modules, a bypass switch and a secondary control protective unit, wherein the equalizing resistor is connected in parallel with all the direct-current supporting capacitors; the first and second power semiconductor switch modules are sequentially connected in series with each other and then are connected in parallel with the direct-current supporting capacitors; the third and fourth power semiconductor switch modules are sequentially connected in series with each other and then are connected in parallel with the direct-current supporting capacitors; the bypass switch is connected in parallel with the second power semiconductor switch module; the converter valve module unit also comprises a power diode; the anode of the power diode is connected with the negative end of the second power semiconductor switch module; the cathode of the power diode is connected with the negative end of the first power semiconductor switch module. The structure can solve the problems that in existing flexible power transmission, the transmission power is limited by elements, equipment is relatively low in efficiency and the protection reliability is poor when equipment has faults. The invention also discloses a modular multi-electric-level current converter.

Description

technical field [0001] The invention belongs to the field of flexible direct current transmission, and in particular relates to a converter valve module unit and a modular multilevel converter composed of the same. Background technique [0002] The core of the flexible DC transmission system is the voltage source converter based on fully controlled devices. Multi-level technology is the optimal solution for realizing high-voltage and large-capacity voltage source converters. Compared with the two-level converter, the multi-level converter can use low-voltage devices to achieve high-voltage level output without direct series connection of switching devices. In recent years, the emergence of Modular Multilevel Converter (MMC) has enabled the successful application of MMC in the field of flexible DC transmission. [0003] The converter valve of the modular multilevel converter adopts a modular design, which is composed of several basic unit sub-modules with the same structure...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a converter valve module unit, which can solve the problems of current flexible power transmission that the transmission power is restricted by devices, the equipment efficiency is low, and the protection reliability is poor in case of failure.

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