In LLC resonant converters, litz-wire high-frequency gapped transformer (HFGT) is one of the most critical components, responsible for efficient operation. However, it is also a major contributor to overall weight and volume. Therefore, designers perform multi-objective optimisation for minimising its losses and size, which is itself complex and cumbersome. This usually requires many iterations because the losses vary non-linearly with the decrease in size. The selection of initial-setup parameter (ISP) values, plays a vital role in overall performance improvement of the optimisation. The closer the ISPs to optimal values, the smaller are the iterations required for convergence. Therefore, this study proposes an optimal peak flux density model (OPFDM), considering the voltage excitation waveform, duty cycle, core material parameters, and the response of litz-wire to high-frequency. The aim is to obtain an optimised HFGT design through a non-iterative approach by directly estimating optimal values of ISPs through OPFDM. The designed HFGT results in minimised losses and size, while keeping the thermal constraints within limits. Moreover, the impact of frequency and duty cycle on OPFDM is also presented. The proposed model is implemented to design HFGT for 380 VDC/12 VDC LLC converter. Comparison-based analytical, finite-elements method and experimental results validate the model.

中文翻译：

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用于LLC谐振转换器中高频间隙变压器（HFGT）的非迭代设计的最佳峰值磁通密度模型（OPFDM）

在LLC谐振转换器中，利兹线高频隙变压器（HFGT）是最关键的组件之一，负责高效运行。但是，它还是总体重量和体积的主要贡献者。因此，设计人员执行多目标优化以最小化其损失和尺寸，这本身就是复杂且麻烦的事情。这通常需要进行多次迭代，因为损耗随尺寸的减小呈非线性变化。初始设置参数（ISP）值的选择在优化整体性能方面起着至关重要的作用。ISP越接近最佳值，收敛所需的迭代越小。因此，本研究提出了一种最佳的峰值磁通密度模型（OPFDM），其中考虑了电压激励波形，占空比，芯材参数，以及绞合线对高频的响应。目的是通过OPFDM直接估算ISP的最佳值，通过非迭代方法获得优化的HFGT设计。设计的HFGT可将损耗和尺寸降至最低，同时将热约束保持在极限范围内。此外，还介绍了频率和占空比对OPFDM的影响。所提出的模型用于设计380 VDC / 12 VDC LLC转换器的HFGT。基于比较的分析，有限元方法和实验结果验证了该模型。还介绍了频率和占空比对OPFDM的影响。所提出的模型用于设计380 VDC / 12 VDC LLC转换器的HFGT。基于比较的分析，有限元方法和实验结果验证了该模型。还介绍了频率和占空比对OPFDM的影响。所提出的模型用于设计380 VDC / 12 VDC LLC转换器的HFGT。基于比较的分析，有限元方法和实验结果验证了该模型。