Modularized multi-level full-bridge resonant power electronic transformer topology

Abstract

The invention belongs to the technical field of power electrons and particularly relates to a modularized multi-level full-bridge resonant power electronic transformer topology. The topology specifically comprises high-voltage side three phases which are of three-phase star connection structures, each phase is of the same structure, and each phase comprises Nt subunits and Nt low-voltage side full-bridge modules; each subunit comprises a resonance LC and a high-frequency transformer, and a high-voltage side MMC full-bridge module of each phase is shown in the description; in every two adjacent subunits, each MMC module generates a part of the base frequency phase voltage output and produces a high-frequency square wave with equal production amplitude and opposite phases at the same time, the high-frequency square wave is filtered and passes through bridge arm resonance LC, and after being separated and reduced voltage by the high-frequency transformer, the high-frequency square wave is rectified by a low-voltage side H bridge module to a low-voltage direct current bus. Compared with the high-voltage side and intermediate topology of a traditional power electronic transformer, the high-frequency transformer number, module number, capacitance number and switch number can be saved, and the topology has a good output waveform at the same time.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a modular multilevel full-bridge resonant power electronics transformer topology. Background technique [0002] A power electronic transformer is a power electronic device with functions such as voltage conversion, reactive power compensation, unbalance control, and power quality management. There are many types of power electronic transformer topologies, the common ones are AC / AC type, AC / DC / DC type and AC / DC / DC / AC type. The AC / AC topology belongs to the matrix structure, and the coupling degree between the bridge arms is high, which affects the quality of the output waveform; the AC / DC / DC type has capacitors for decoupling, and the output waveform quality is better. At the same time, this topology can Provide high-voltage and low-voltage DC busbars to facilitate grid interconnection; AC / DC / DC / AC type adds a low-voltage DC side inverter link on the basis o...

AI Technical Summary

Problems solved by technology

[0003] Compared with traditional transformers, power electronic transformers have complex structures, many types and quantities of components, low power density, and high overall cost

The AC / AC type with a lower number of stages in the above-mentioned power electronic transformer structure is difficult to ensure a good waveform, and the AC / DC / DC / AC type with a larger number of stages has a complex structure

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