Wide-input-voltage single-stage LLC isolation voltage stabilizing circuit

Abstract

A wide input voltage single-stage LLC isolation voltage stabilizing circuit disclosed by the present invention comprises an LLC resonant circuit, a pre-voltage-stabilization control circuit and a phase-locked chopper voltage stabilizing circuit, the input end of the pre-voltage-stabilization control circuit and the input end of the LLC resonant circuit are both connected with a voltage input end, the output end of the pre-voltage-stabilization control circuit is connected with the control end of the LLC resonant circuit, and the phase-locked chopper voltage stabilizing circuit is connected with the output end of the LLC resonant circuit. The output end of the LLC resonant circuit is connected with the input end of the phase-locked chopper voltage stabilizing circuit, the signal acquisition end of the phase-locked chopper voltage stabilizing circuit is connected with the control end of the LLC resonant circuit, and the output end of the phase-locked chopper voltage stabilizing circuit is connected with the voltage output end. According to the invention, single-stage LLC wide voltage input and stable voltage output are realized through the improvement of the topological structure.

Description

Technical field [0001] The present invention relates to a wide input voltage single stage LLC isolation regulator circuit. Background technique [0002] At present, the DC-DC power converter used by the new energy vehicle is mainly implemented in the following manner: First, use the Boost plus LLC topology, through the two-stage circuit to achieve wide voltage input, regulator output, input voltage range 200V-750V; Second, use the transparent full bridge topology to achieve a single-stage wide voltage input, the input voltage range is generally 350V-700V, the voltage range is narrow, and the existence of the full bridge has a problem of hard switch, light The load noise is large; third, the single-stage wide voltage input is realized using a positive and inverting circuit, and the input voltage ranges from 200V to 750V, but the topology is a hard switch, and the transformer is large, and it is not suitable for light weight. [0003] LLC generally uses the modulated mode to achiev...

AI Technical Summary

Problems solved by technology

[0002] At present, the wide voltage input performance of DC-DC power converters used in new energy vehicles is mainly achieved through the following methods: First, use BOOST plus LLC topology to realize wide voltage input and regulated output through two-stage circuits. The input voltage range is 200V-750V; Second, use the phase-shifted full-bridge topology to achieve single-stage wide voltage input, the input voltage range is generally 350V-700V, the voltage range is narrow, and the phase-shifted full-bridge has the problem of light load working on hard switches, light The load noise is large; thirdly, the forward and flyback circuit is used to realize single-stage wide voltage input, and the input voltage range is 200V-750V, but this topology is hard switching, and the transformer is large in size, which is not suitable for lightweight

[0003] LLC generally adopts frequency modulation to achieve output voltage regulation. A wide input voltage range will cause the following problems: the primary excitation current of the LLC is very large when the input voltage is low, and the heat is severe under light load, and even cannot work normally; the operating frequency of the LLC when the input voltage is high Extremely high, the switching tube cannot meet the frequency requirements

To sum up, due to the topology limitation of LLC, the existing single-stage LLC cannot achieve wide voltage input while guaranteeing a regulated output

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