Modular multi-level high-power alternating-current/alternating-current converter based on high-frequency transformer

Abstract

The invention discloses a modular multilevel high-power alternating-current / alternating-current converter based on a high-frequency transformer. The converter comprises a first bridge arm, a second bridge arm and a third bridge arm, and each of the first bridge arm, the second bridge arm and the third bridge arm is formed by cascading n sub-modules, wherein each sub-module includes two H-bridge converters, a high-frequency transformer and a cycle converter which are connected in sequence. The converter has a modular design, is easy to expand, and has good output voltage waveform quality, no loop current, high power density and low cost, and has advantages of few bridge arms, a small IGBT total capacity, a small capacitor number and a high direct current voltage minimum harmonic component frequency.

Description

technical field [0001] The invention belongs to the field of structural design of high-power power conversion devices, and relates to a modular multi-level high-power AC-AC converter based on high-frequency transformers. Background technique [0002] High-power high-voltage AC-AC converters are widely used in practical engineering, and play an irreplaceable role in asynchronous networking, offshore wind power, long-distance frequency division power transmission, subsea oil and gas exploration, and future subsea power transmission and distribution system construction. In addition, high-power AC / AC inverters are also indispensable in large-scale industrial equipment such as motor drives, ore crushers, and rolling mills required in rail transit, mining, smelting, and steel rolling industries. [0003] The modular multilevel matrix converter (modular multilevel matrix converter, M3C) was proposed by R.W.Erickson and O.A.Al-Naseem of the University of Colorado in 2001. M3C retai...

AI Technical Summary

Problems solved by technology

Compared with MMC and M3C, Hexverter only uses 6 bridge arms to realize the connection of two three-phase AC systems with different frequencies and amplitudes, which reduces the equipment volume and production cost, but the topology of Hexverter determines its internal circulation There is only one channel, so that the system must meet strict reactive power constraints during normal operation, which greatly limits the application of this new AC converter in practical engineering

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