Improving Efficiency of Beyond-10 MHz LLC Resonant DC–DC Converters Using Spiral Transformers With Magnetic Flux Path Control Technology
Improving Efficiency of Beyond-10 MHz LLC Resonant DC–DC Converters Using Spiral Transformers With Magnetic Flux Path Control Technology
复制标题
使用具有磁通路径控制技术的螺旋变压器提高超过 10 MHz LLC 谐振 DC-DC 转换器的效率
DOI：
10.1109/tmag.2021.3113998
复制
发表时间：
2021
影响因子：
2.1
通讯作者：
T. Mizuno
中科院分区：
文献类型：
--
作者：
K. Shimura;S. Kobayashi;Mitsuhide Sato;T. Mizuno
开关电源中使用的变压器可以通过提高频率来减小尺寸。然而，变压器中的损耗在较高的驱动频率下增加，这阻碍了较高的效率。变压器已经从绕组堆叠在顶部的平面型转变为绕组以螺旋形状缠绕的螺旋型，作为更紧凑的结构。因此，本文提出了磁通路径控制（MPC）技术来降低螺旋Transformer的损耗。通过磁场模拟和实际测量，我们发现将MPC应用到螺旋Transformer中可以降低交流电阻。通过将MPC应用于螺旋Transformer，在15 MHz处的交流电阻从656下降到478 $\text{m}\Omega $，对于阻抗分析仪的实际测量，下降了27%。此外，电源的效率改善效果的建议Transformer已被证明在一个超过10 MHz的48 V/6 V 18 W LLC谐振DC-DC转换器原型与氮化镓（GaN）器件。通过将所提出的Transformer应用于原型，满载效率提高了4.0%，从65.2%提高到69.2%。这些结果表明，MPC的应用可以降低螺旋Transformer的交流电阻，提高LLC谐振DC-DC变换器的效率。
Transformers used in switching power supplies can be reduced in size by increasing the frequency. However, the loss in transformers increases at higher drive frequency, which hinders higher efficiency. Transformers have transitioned from a planar type in which windings are stacked on top to a spiral type in which windings are wound in a spiral shape as a more compact structure. Therefore, herein, the authors proposed the magnetic flux path control (MPC) technology to reduce the loss of the spiral transformer. We revealed by magnetic field simulation and actual measurement that the ac resistance can be reduced by applying MPC to the spiral transformer. By applying MPC to the spiral transformer, the ac resistance at 15 MHz was reduced by 27% from 656 to 478 $\text{m}\Omega $ for the actual measurement by the impedance analyzer. Also, the efficiency improvement effect of power supplies by the proposed transformer has been demonstrated in a beyond-10 MHz 48 V/6 V 18 W LLC resonant dc–dc converter prototype with gallium nitride (GaN) devices. By applying the proposed transformer to the prototype, the full-load efficiency improved by 4.0%, from 65.2% to 69.2%. These results show that the application of MPC can reduce the ac resistance of the spiral transformer and increase the efficiency of the LLC resonant dc–dc converter.