DAB type single-stage bidirectional AC/DC converter with low voltage stress and wide output range

Abstract

A DAB (dual active bridge) type single-stage bidirectional AC / DC converter with low voltage stress and wide output range is formed by cascading an AC filter, a cycloconverter, n high-frequency transformers with primary sides connected in series, n full-bridge circuits, a DC filter and a variable structure switch group in sequence, wherein the secondary side of each transformer is connected with the full-bridge circuit through a leakage inductor, the output ends of the n full-bridge circuits are connected in series or in parallel through the variable structure switch group, and n groups of dual-active bridge structures are formed by the cycloconverter, the n high-frequency transformers and the n full-bridge circuits. The converter adopts a current outer-loop power inner-loop control strategy, can work in a rectification and inversion mode, and realizes the bidirectional AC / DC conversion and th eAC side power factor control. The converter adopts a DAB structure to reduce the switching voltage stress of the cycloconverter, belongs to the single-stage power conversion, does not have a direct current link, and improves the reliability of the converter; the n groups of dual-active bridge structures and the variable structure switch group improve the capacity of the converter, and the converter is suitable for high-power occasions.

Description

Technical field: [0001] The invention relates to a DAB type single-stage bidirectional AC / DC converter with low voltage stress and wide output range, which belongs to the field of electric energy conversion. Background technique: [0002] With the rapid development of the economy and the improvement of living standards, automobiles have become an indispensable means of transportation. Using new energy to gradually replace traditional fossil fuels to drive automobiles is an inevitable trend in the future development of the automobile industry. With the support of new infrastructure, the construction of charging equipment has also developed rapidly with the increase in the number of electric vehicles, and has a broad space for development. [0003] A large number of electric vehicles are connected to the grid, which also makes the rational use of the interaction between vehicles and the grid to achieve optimal charging become a research hotspot. If these vehicles are allowed ...

AI Technical Summary

Problems solved by technology

[0004] Bidirectional AC / DC converter is an important link between electric vehicles and power grids. Existing research mainly focuses on two-stage structures. This type of structure has two-stage power conversion, low power density, unsatisfactory conversion efficiency, and long life of DC bus electrolytic capacitors. low level problem

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