AC-AC three level AC-AC converter based on positive converter

Abstract

This invention discloses an AC-AC three-level converter based on normal converter, in which, the circuit of the converter is composed of an input high voltage AC supply, an input filter, a multi-level converter, a HF transformer, a cycle converter, an output filter and output AC load, in which, the multi-level converter is composed of one or many basic units to convert the input voltage to multiple output levels, said basic unit is made up of two four quadrant power switches and one four-quadrant clamp power switch and the circuit topology group based on the AC-AC three-level converter of a normal converter includes normal, push-and-pull, semi-bridge and full bridge topologies, which reduces voltage stress of power switch, series of power conversion and increases power factors of input side, conversion efficiency and power density.

Description

technical field [0001] The invention belongs to power electronic conversion technology, in particular to an AC-AC three-level AC-AC converter based on a forward 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-electrically isolated, low-frequency and high-frequency electrically isolated; 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 limited to non-isolate...

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 newAC / AC multilevel converter family", IEEE Transactions on Industrial Electronics, 2005, Vol.52, No. .3, pp.662~669.), its circuit structure consists of a 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 application in high-voltage AC-AC conversion, etc., but 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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