Optimal design method of LLC resonant converter

Abstract

The invention discloses an optima design method of an LLC resonant converter. The method comprises the following steps: determining transformer ratio of transformation according to a design index of an LLC resonant converter; determining the primary side turns, the secondary side turns, a winding structure and a magnetic core shape of the transformer according to the ratio of transformation of thetransformer, and initially designing a transformer; measuring a parasitic capacitance of the transformer; deducing the relation formula of switch-on loss and dead time to obtain the optimal dead timewhen the switch-on loss is minimum; determining the optimal magnetic inductance according to the optimal dead time; selecting the inductance ratio and quality factor capable of satisfying a gain condition; and obtaining a resonance inductance value and a resonance capacitance value according to the optimal magnetic inductance, the inductance ratio and the resonance frequency; and changing the airgap of the transformer to enable the magnetic inductance to be equal to the optimal magnetic inductance. Through the method disclosed by the invention, the problem that the traditional LLC resonant converter design method depends too much on the experience and is inaccurate is solved, the design result is more accurate, and can be popularized to various application occasions.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an optimal design method of an LLC resonant converter. Background technique [0002] Since its birth, LLC resonant converter has received more and more attention because of its outstanding advantages. The LLC resonant converter can realize the soft turn-on of the primary side switching tube in the whole working range, even if the switching frequency is high, it can still achieve high efficiency. The increase of the switching frequency is beneficial to reduce the size of the transformer and the filter, and the resonant inductance and the excitation inductance can be integrated into the transformer, so a very high power density can be achieved. [0003] Because the LLC resonant converter has the above-mentioned advantages, how to utilize the advantages of the LLC resonant converter through precise design has become a hot issue that researchers in related fields pay attention t...

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Problems solved by technology

[0005] In order to solve the above-mentioned defects existing in the prior art, the object of the present invention is to provide a method for optimizing the design of LLC resonant converter with the goal of improving efficiency, taking into account the parasitic capacitance of the transformer, and solving the problem of traditional LLC resonant converter design. The problem that the method is too dependent on experience and not accurate enough can be extended to various applications

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