Power supply circuit for outputting low-voltage large current based on LLC resonant conversion

Abstract

The invention discloses a power supply circuit for outputting low-voltage large current based on LLC resonant conversion, the power supply circuit comprises six primary side input circuits and twelvesecondary side output circuits, the primary side is an LLC resonant circuit with two high-frequency star connection modes, and one primary side input circuit corresponds to two secondary side output circuits; each primary side input circuit comprises two switches, an inductor, a resonant capacitor and a primary side of a transformer; each secondary side output circuit comprises a transformer secondary side and an output diode or MOS tube. Input voltage is added to the six primary side input circuits and then output through twelve secondary sides of the six transformers. Six paths of primary side interleaving LLC resonant conversion and twelve paths of secondary side interleaving are adopted, so that the output current pulsation is greatly reduced, the capacitor size is greatly reduced, thecost is greatly reduced, the low-voltage high-current power supply device with relatively low cost, high efficiency, high power degree and high reliability is realized, and batch productization is facilitated.

Description

[technical field] [0001] The invention relates to the technical field of switching power supplies, in particular to a power supply circuit that outputs low voltage and high current based on LLC resonance conversion. [Background technique] [0002] At present, in the power supply outputting low voltage and high current, such as 20VDC / 1000A, the DCDC conversion technology of the power supply is mostly phase-shifted full-bridge technology. This technology has relatively low conversion efficiency, large volume, and low power density; if a single Full-bridge LLC resonant DCDC conversion, using MOSFET full load range zero-voltage switching (ZVS) in the LLC full-bridge resonant circuit, when the switching frequency is less than or equal to the resonant frequency, the shutdown current is greatly reduced by increasing the excitation inductance, and the secondary rectifier diode is almost Without reverse recovery, these features can improve the conversion efficiency, but there is too ...

AI Technical Summary

Problems solved by technology

However, the current pulsation at the output end of this solution is too large, and too many capacitors are needed to filter out the output current pulsation. The circuit with too many capacitors is basically only theoretically feasible. First, it requires a large space and volume, and the cost is high. The bottleneck is due to the space limitation of layout and wiring in engineering, which will cause the electrolytic capacitor closest to the secondary side rectifier to overheat, and there is a great potential reliability hazard

Images