Cuk-converter-based high-frequency isolated three-level alternating current (AC)-AC converter

Abstract

The invention discloses a Cuk-converter-based high-frequency isolated three-level AC-AC converter. In the converter, two coupling capacitors in a non-isolated Cuk three-level topology are both divided into two parts between which a serial isolated transformer is inserted; the middle connecting points of the primary sides of the two transformers are connected with the middle points of two bidirectional power switch tubes on the left side and the middle points of the two bidirectional power switch tubes on the right side respectively; and a power supply end and an output end form a circuit topological structure capable of converting an unstable high-voltage current into a stable or adjustable common-frequency sinusoidal alternating current by combining an input filter and an output filter respectively. In the invention, the power conversion stage number is small, fewer power switch elements are used, a bidirectional power current can be realized, the converter has an electrical isolation property, the spectral characteristic of the front end voltage of the output filter is desirable, the conversion efficiency and power density are improved, a voltage regulation range is wide, voltage boosting and reducing regulation can be realized, and the volume and weight of the output filter can be realized.

Description

technical field [0001] The invention belongs to power electronic conversion technology, in particular to a high-frequency isolated three-level AC-AC converter based on a Cuk 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 multi-level DC-DC, DC-AC and AC-DC converters, while research on multi-level AC-AC converters is very small, and is limited t...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the shortcomings of excessive voltage stress of power switching tubes in high-power power supplies, AC-AC converters generally have many conversion stages, complex circuits and no electrical isolation function, the present invention provides a high-frequency isolated three-phase converter based on Cuk converters. Level AC-AC converter, which has the advantages of single-stage power conversion, bidirectional power flow, good spectral characteristics of output filter front-end voltage, buck-boost conversion, reduced voltage stress of switching devices, and effective electrical isolation.

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