Closed-loop start-up method of resonant converter

Abstract

The invention discloses a closed loop starting method for a resonant converter. The resonant converter comprises a bridge circuit, a resonant circuit, a transformer, a rectifier circuit, a filter circuit, an input detection circuit, a driving circuit, a peak detection circuit, an output detection circuit and a digital processor, wherein the bridge circuit, the resonant circuit, the transformer, the rectifier circuit and the filter circuit are sequentially connected in series. The input detection circuit is connected to the input end of a resonant transformation device to detect the input voltage and send the input voltage to the digital processor. The driving circuit is connected to the digital processor and converts a PWM signal into the driving level so as to drive the bridge circuit. The peak detection circuit is connected with the resonant circuit, detects the resonant current peak and sends the resonant current peak to the digital processor. The output detection circuit detects the output voltage and the output current and sends the output voltage and the output current to the digital processor. According to the closed loop starting method for the resonant converter, due to the fact that the peak detection circuit detects the resonant current peak, implementation is easy. Closed loop control is conducted on the resonant current peak in the starting process, control is easy, it is ensured that the overcurrent of the resonant converter cannot occur in the starting process, and the starting time is made optimal.

Description

technical field [0001] The invention belongs to the technical field of DC / DC converters, and more specifically, relates to a closed-loop starting method of a resonant converter. Background technique [0002] High efficiency, high power density, and high reliability have always been the development trend of switching converters. At present, resonant soft switching technology has been widely used in switching converters to improve converter efficiency and power density. The LLC resonant converter works above the resonant frequency, which can realize the zero-voltage conduction of the input bridge switch tube, and can also realize the zero-current shutdown of the output rectifier diode within a certain load range, so it has high efficiency, small size, electromagnetic Good compatibility and other advantages have attracted widespread attention in recent years. [0003] Different from general converters, LLC resonant converters use pulse frequency modulation (Pulse Frequency Mod...

AI Technical Summary

Problems solved by technology

[0009] Aiming at the defects of the prior art, the purpose of the present invention is to provide a closed-loop start-up method for the resonant converter, aiming at solving the technical problem that the start-up time of the LLC resonant converter is relatively long in the prior art

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