In this study, a novel ‘ ’ dual-control modulation is proposed for the MHz-level CLLC converters in battery charging applications. Phase shift between the primary and secondary switches is utilised as an additional control variable to effectively reduce the power losses, especially in light- and medium-load conditions. Compared to other state of the art, a more generalised theoretical model is developed to characterise the converter with higher accuracy based on extended harmonic approximation. Furthermore, a numerical algorithm is utilised to thoroughly examine the converter performance under various operating conditions and systematically search for the optimised design parameters under the proposed modulation scheme. The modelling and optimisation are verified by simulation on a 3.3 kW onboard charger design for electric vehicles, which shows an estimated efficiency enhancement between 1 and 4%. Finally, a laboratory prototype has been developed using gallium nitride semiconductor devices, at the resonant frequency of 1 MHz. The converter measured efficiencies are 96.4, 96.2 and 94% for the selected heavy, medium- and light-load conditions, respectively. This system would allow insights into the practical implementation and evaluation of utilising wide bandgap semiconductors to achieve both high power density and enhanced efficiency for emerging power electronic systems.

中文翻译：

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在电池充电应用中将功耗降至最低的双控制MHz级CLLC转换器的建模和优化

在这项研究中，一本小说 对于电池充电应用中的MHz级CLLC转换器，提出了双控制调制。主开关和副开关之间的相移被用作附加控制变量，以有效减少功率损耗，尤其是在轻负载和中等负载条件下。与其他现有技术相比，基于扩展的谐波逼近，开发了一种更通用的理论模型来以更高的精度表征转换器。此外，利用数值算法来彻底检查各种工作条件下的转换器性能，并在提出的调制方案下系统地搜索优化的设计参数。建模和优化通过仿真验证，用于电动汽车的3.3 kW车载充电器设计，估计效率提高了1-4％。最后，使用氮化镓半导体器件开发了实验室原型，谐振频率为1 MHz。对于选定的重载，中载和轻载条件，转换器测得的效率分别为96.4％，96.2和94％。该系统将有助于深入了解利用宽带隙半导体实现新兴电力电子系统的高功率密度和更高效率的实际实现和评估。