Phase-to-phase current sharing of illc resonant converter and the method of prolonging power-down maintenance time

Abstract

Provided is an iLLC resonant converter, comprising two LLC resonant converters, a digital controller and two switch control inductors. Power transformers of the two LLC resonant converters are respectively provided with an auxiliary winding, the two switch control inductors are respectively connected in parallel to the auxiliary windings, the parameters and structures of the two LLC resonant converters are the same, input ends of the two LLC resonant converters are connected in parallel, and output ends thereof are also connected in parallel, and the parameters and structures of the two switch control inductors are the same. According to the resonant converter provided in the present invention, the respective output currents and common input voltage of two LLC resonant converters are sampled by means of a digital controller, the phase angle of switch control inductors is adjusted through operation to realize current sharing of a resonant cavity, and the direct-current voltage gain of the resonant cavity can be adjusted according to the voltage of a direct-current bus during input power-down, thereby prolonging the power-down hold-up time of the converter.

Description

technical field [0001] The invention relates to the field of power electronics technology and its application, in particular to an iLLC resonant converter and a method for sharing current between phases and prolonging power-off maintenance time. Background technique [0002] The output voltage of switching power supply such as server group power supply and communication power supply is low, and the output current is relatively large, and the power supply is required to maintain a normal constant voltage output of more than ten milliseconds after the power grid is powered off, so that the uninterruptible power supply (UPS) can operate during this period Provide backup energy for these power sources. This period of ten milliseconds is called the hold-up time. The LLC resonant converter is an inductance-inductor-capacitor series resonant DC-DC converter with a narrow frequency range and a wide voltage regulation range. It can realize zero-voltage soft switching in the full loa...

AI Technical Summary

Problems solved by technology

The invention patent "A Current Sharing Regulation Method for Interleaved Parallel LLC Resonant Circuits" (201810195443.9) adopts the detection of the current or voltage error of each LLC branch, and adjusts the duty ratio of each LLC branch according to the error to adjust the gain of each LLC branch to realize Current sharing, which is a control method to adjust the pulse width, can solve the current sharing problem, but it does not help to prolong the power-off maintenance time

However, this method can no longer integrate the resonant inductor into the transformer, which increases the size of the converter

[0007] None of the methods given in the above documents and patents can simultaneously meet the needs of phase-staggered resonant cavity current balance adjustment and extended power-off maintenance time.

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