A high-frequency isolated AC/DC conversion circuit and a control method thereof

Abstract

The invention discloses a high-frequency isolated AC-DC conversion circuit and a control method thereof. The circuit comprises an input filter, an input transformer, an AC rectifier unit, an energy storage filter unit, a resonant conversion unit, an isolation transformer, a DC side rectifier unit and an output energy storage unit. The conversion circuit of the invention can work in three modes ofrectification, inverter or standby. By using the input transformer, the common-mode current on the AC side and the AC anti-deviation function can be effectively rejected while the energy storage function is realized, and the common-mode interference of the AC rectifier unit to the ground can be effectively reduced. In addition, the resonant conversion unit can realize the bi-directional conversionof soft switch, which reduces the on and off stress of each component and reduces the switching loss. Finally, multi-state conversion can be realized in the bi-directional conversion of DC voltage ina wide range by using the combination of resonant conversion unit and DC side rectifier unit to turn on the timing control.

Description

technical field [0001] The invention relates to a switching power supply, in particular to a high-frequency isolated AC-DC conversion circuit and a control method thereof. Background technique [0002] In applications that require AC-DC bidirectional conversion (that is, with rectification and inverter modes), such as inverters for energy storage systems, hybrid power grid-connected inverters, lithium battery factory composition capacity, aging detection, etc. , the traditional two sets of circuits of rectification and inverter, or the scheme of low-frequency isolation transformer plus high-frequency inverter, so the volume is large, and the cost performance is poor in the field of small power; the main reason is that the high-frequency isolation two-way Transformation technology is difficult to implement. The low-frequency transformer isolation technology is relatively mature and stable. Therefore, compared with the high-frequency isolation technology, the combination of t...

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Problems solved by technology

[0004] The main purpose of the present invention is to propose a high-frequency isolated AC-DC conversion circuit and its control method that can be switched to work in standby mode, rectification mode and inverter mode, so as to solve the problem that the existing AC-DC bidirectional conversion circuit is complicated and difficult to design. The technical problem of realizing high-frequency isolation and low work efficiency

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