Half-bridge LLC resonant converter staggered parallel circuit and current sharing control method thereof

Abstract

The invention provides a half-bridge LLC resonant converter staggered parallel circuit and a current sharing control method thereof. Two phase half-bridge LLC resonant converters are staggered and connected in parallel. Two capacitors connected in series are on the direct current input side of each phase half-bridge LLC resonant converter, and a resonant cavity is connected through a T-switch network. The secondary side of a transformer is connected with a rectifier circuit, an output capacitor and a load. According to the invention, the insertion of the Vin / 2 state in the input voltage of theresonant cavity is realized by adding an auxiliary path and MOS tubes, so as to reduce the effective value of the fundamental wave of the input voltage of the resonant cavity; the gain of the LLC resonant converters can be reduced while the switching frequency remains unchanged; in the case of parallel interleaving at the same frequency, the resonance current of each phase can be compared with the average value of the resonance current of a parallel system; the gain of each phase LLC resonant converter is adjusted to achieve current sharing control; and all MOS tubes on the primary side can achieve zero voltage turn-on.

Description

technical field [0001] The invention relates to the field of power electronic converters, in particular to an interleaved parallel current sharing circuit and a control method thereof. Background technique [0002] The LLC resonant converter has the advantages of high efficiency and high power density, and has been widely used. The LLC resonant converter adopts frequency modulation control (PFM) to control the gain of the converter by controlling the switching frequency. The interleaved parallel connection of multi-phase LLC resonant converters can improve the system power level and reduce the output ripple, which is beneficial to reduce the output capacitance. Interleaved parallel multi-phase LLC resonant converters need to work at the same switching frequency, so as to maintain a fixed phase difference. However, the inevitable parameter deviation of circuit components will cause the gain deviation of each phase LLC resonant converter, resulting in uneven current of each ...

AI Technical Summary

Problems solved by technology

However, the inevitable parameter deviation of circuit components will cause the gain deviation of each phase LLC resonant converter, resulting in uneven current of each phase, threatening the reliable operation of the system

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