Parameter design method of full-bridge LLC resonant converter

Abstract

The invention provides a parameter design method of a full-bridge LLC resonant converter. According to the method, the values of a primary and secondary turn ratio, magnetizing inductance, resonant inductance and resonant capacitance of the transformer are determined according to preset target parameters, and when the four parameters are determined, the magnitudes of a dead time, the switching current of a switch tube and the equivalent junction capacitance of the actual switch, the turn-off current of the switch tube and the equivalent junction capacitance of an actually selected switch tubeare fully considered. While a converter gain is satisfied, the ZVS of a primary switch tube during the actual operation of the converter, primary and secondary RMS current and the switch tube turn-offcurrent are reduced at the same time, and the loss of a switching device is reduced. In addition, the operating frequency of the converter can be strictly defined in a preset range, and the design ofan input side filter and the design of the transformer are facilitated.

Description

technical field [0001] The invention relates to a parameter design method of an LLC resonant converter, in particular to a parameter design method of a full-bridge LLC resonant converter. Background technique [0002] The LLC resonant converter can realize the soft switching technology of zero voltage switch (ZVS) of the primary switch tube and zero current switch (ZCS) of the secondary rectifier diode, which can achieve higher switching frequency at high switching frequency. High system efficiency has been widely used in notebook computer adapters, LED drivers, battery chargers, and photovoltaic power generation. The key to realize efficient operation of LLC resonant converter lies in reasonable circuit parameters. How to ensure the normal operation of the system through reasonable and effective parameter design and how to give full play to the advantages of LLC has become an important topic for researchers in this field. [0003] At present, among the existing parameter ...

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Problems solved by technology

[0003] At present, among the existing parameter design methods, the patent 201510355688.X proposes an optimal design method of LLC resonant converter based on power factor angle evaluation, which reduces the reactive circulating current of the resonant tank, but does not take into account the secondary rectifier diode loss of

Patent 201410785483.0 proposes a design method for an output intrinsically safe LLC resonant converter, which not only improves the electromagnetic compatibility performance of the power supply, but also ensures the intrinsic safety performance of the converter, but the actual operating frequency range of the converter cannot be determined during the design process , which brings inconvenience to the design of the input side filter and the design of the transformer

In addition, Deng Xiang, Li Dawei, and Yang Shanshui proposed the design of resonant components in LLC converters (Power Electronics Technology, 2013, 47(2): 7-9+14) by analyzing the relationship between the excitation inductance and the resonant inductance of the primary side of the transformer. The effect of the ratio K and quality factor Q on the performance of the converter gives a simple and fast design process for the resonant element. However, in the design process, although the resonant cavity is inductive, the dead time and the equivalent structure of the switching tube used are not considered. The size of the capacitor, and the actual ZVS of the primary side switch tube may be lost and the value of K is based on the empirical method, which brings some inconvenience to the designer in the actual design process

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