High frequency isolated AC-AC mode three-level AC-AC converter based on flyback converter

Abstract

The present invention discloses a high frequency isolated AC-AC mode three-level AC-AC converter based on a flyback converter. The circuit typology of the converter consists of a high voltage AC power supply, an input filter, a high frequency isolated flyback three-level converting unit, a cycloconverter and an output AC load which are successively linked together, wherein the high frequency isolated flyback three-level converting unit, being composed of two bidirectional power switches, a bidirectional clamp power switch and a high frequency isolated flyback three-circuit transformer, can convert the input voltage to a plurality of output levels. The invention reduces voltage stress of the power switches and series of power conversion, and increases power factors of input side, conversion efficiency, and power density. The high frequency isolated AC-AC mode three-level AC-AC converter is applicable to high frequency electrically-isolated high voltage AC-AC electric energy converting occasions, and greatly widens the application field of the three-level AC-AC converter.

Description

technical field [0001] The invention belongs to power electronic conversion technology, in particular to a high-frequency isolated AC-AC three-level AC-AC converter based on a flyback converter. Background technique [0002] AC-AC conversion technology is a conversion technology that uses power semiconductor devices to convert AC power of a certain frequency and amplitude into AC power of the same or another frequency and amplitude. It is widely used in National defense, industrial and mining enterprises, scientific research institutes, university laboratories and daily life. [0003] So far, research on AC-AC converters by power electronics researchers at home and abroad has mainly focused on two-level AC-AC converters such as non-electrical isolation, low-frequency and high-frequency electrical isolation; for multi-level converters Research mainly focuses on multilevel DC-DC, DC-AC and AC-DC converters, while research on multilevel AC-AC converters is very small, and is l...

AI Technical Summary

Problems solved by technology

Although the AC-DC-AC multi-level AC-AC converter and the Buck non-isolated AC-AC three-level AC-AC converter have their own advantages, the former has complex circuit topology, many power conversion stages, The input side has defects such as low power factor, low conversion efficiency, and low power density; while the latter has defects such as single topology, only step-down conversion, and no electrical isolation.

[0004] M.Glinka et al proposed an intermediate frequency isolated AC-DC-AC multilevel AC-AC converter ("A new AC / AC multilevel converter family", IEEE Transactions on Industrial Electronics, 2005, Vol.52, No.3, pp.662~669.), its circuit structure consists of modular multilevel AC-AC converter (M 2 LC), intermediate frequency transformer, rectifier, inverter and filter, etc. It has the advantages of electrical isolation, controllable output voltage, modularization, and is suitable for high-voltage AC-AC conversion, etc., but it has complex topology and many power conversion stages ( Low frequency AC LFAC-DC DC-medium frequency AC MFAC-DC DC-low frequency AC LFAC), low input side power factor, low conversion efficiency and power density, large volume and weight, complex control and other defects

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