A Modified High-Efficiency LLC Converter With Two Transformers for Wide Input-Voltage Range Applications

    Authors

    H. B. Hu; X. Fang; F. Chen; Z. J. Shen;I. Batarseh

    Comments

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    Abbreviated Journal Title

    IEEE Trans. Power Electron.

    Keywords

    DC Gain; LLC converter; microinverter; optimization; SERIES RESONANT CONVERTER; STEADY-STATE ANALYSIS; FREQUENCY; INVERTERS; DESIGN; Engineering, Electrical & Electronic

    Abstract

    This paper proposed a modified LLC converter with two transformers in series, which has four operation configurations, covering the range of four times the minimum input voltage. To optimize the proposed LLC converter in an attempt to achieve good efficiency, a numerical method is developed based on the LLC converter's steady-state equations. In order to minimize the magnetizing current and thus minimize the conduction and core losses, an optimal objective is proposed to find the maximum magnetizing inductance. An optimization procedure and a design example are given. A 250-W 210-V output prototype with input voltage ranging from 25 to 100V is built to verify the developed numerical model and optimal design method. The dc gain obtained from experimental data agrees pretty well with that from the developed numerical model. Two conventional LLC converters are designed using fundamental harmonic approximation and the proposed optimal design, respectively, to make comparison with the proposed LLC converter and validate the proposed optimal design. Experimental results show that the proposed converter with proposed optimal design can achieve the peak efficiency up to 98%, while maintaining a very wide input voltage range.

    Journal Title

    Ieee Transactions on Power Electronics

    Volume

    28

    Issue/Number

    4

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    1946

    Last Page

    1960

    WOS Identifier

    WOS:000314698300042

    ISSN

    0885-8993

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