This paper suggests a DC/DC converter with coreless transformer for electric vehicle chargers. Since the coreless transformer has low coupling coefficient, the converter uses resonance but its power is controlled by PWM. Appropriate design of resonant capacitor improves its switching conditions of ZVS operation of all switching devices and near ZCS of bottom switches and output rectifier. Using Wheeler approximation, coreless transformer design is suggested and converter design procedure is derived under a predetermined leakage inductance of coreless transformer. The feasibility of the proposed charger is verified with a 2kW prototype designed based on the procedure.

中文翻译：

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一种用于轻型电动汽车车载充电器的带无芯变压器的谐振 PWM DC/DC 转换器

本文提出了一种用于电动汽车充电器的带有无芯变压器的 DC/DC 转换器。由于无铁芯变压器耦合系数低，转换器采用谐振，但其功率由PWM控制。谐振电容的适当设计改善了其所有开关器件的 ZVS 操作以及底部开关和输出整流器的 ZCS 附近的开关条件。使用惠勒近似，建议无芯变压器设计，并在预定的无芯变压器漏电感下推导出转换器设计程序。所提出的充电器的可行性通过基于该程序设计的 2kW 原型进行验证。