High-gain insulation-type three-level-type multi-path output DC-AC converter without lost duty ratio

Abstract

The invention discloses a high-gain insulation-type three-level-type multi-path output DC-AC converter without a lost duty ratio. The front stage of the converter is a BOOST converter, the middle stage is an LLC resonant converter, the original edges of the LLC resonant converter are in parallel connection, the two paths of auxiliary edges of the LLC resonant converter conduct independent output,and the back stage of the converter is an H-bridge converter; the converter comprises two high-frequency insulation transformers, the original edges of the two high-frequency insulation transformers are in parallel connection and are connected to an LLC resonant network, the other end of the LLC resonant network is connected with a bridge-type circuit and a BOOST circuit in sequence, and the auxiliary edges of the two high-frequency insulation transformers are connected with a rectifying circuit and an H-bridge inverter in sequence respectively and conduct independent output. According to theconverter, the high-gain no-load voltage ratio is achieved through a three-level-type structure, electrical insulation of the original edges and auxiliary edges is achieved through a middle-stage LLCcircuit, and the safety is high; the duty ratio of the LLC circuit is not lost, the LLC circuit is easy to control, through independent output of the two paths of the auxiliary edges, the number of converters is reduced, and the cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a high-gain isolated three-stage multi-output DC-AC converter without loss of duty cycle. Background technique [0002] With the continuous development of science and technology, the development of DC-AC converters with wide input range, high gain, isolation, and multiple outputs has become a hot trend. Through the multi-stage structure to adjust the gain together, so as to achieve wide input range and high gain; through the use of interleaved parallel structure in the front stage, so as to reduce the output current ripple of the front stage and reduce the output filter volume of the front stage; the middle stage adopts The isolated converter realizes electrical isolation to ensure the safety of the converter, and adopts soft switching technology to reduce the loss of the switching process of the switching tube, suppress the voltage peak during the switching...

AI Technical Summary

Problems solved by technology

[0003] In order to realize the soft switching of the switching tube, it is usually necessary to sacrifice part of the electrical performance of the converter. For example, the phase-shifted full-bridge soft switching technology realizes the soft switching of the switching tube through the leakage inductance, but the more energy stored in the leakage inductance, the more the duty cycle is lost. The larger the frequency conversion LLC converter, although it can realize the soft switching of the switching tube, it will lead to the increase of the EMI radiation of the circuit, which will increase the design difficulty of the secondary side synchronous rectification and filter

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