Design of Self-Resonant Spiral Coils for Mid-Range, High-frequency Wireless Power Transfer Systems
Design of Self-Resonant Spiral Coils for Mid-Range, High-frequency Wireless Power Transfer Systems
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用于中程高频无线电力传输系统的自谐振螺旋线圈设计
DOI：
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Jungwon Choi
中科院分区：
文献类型：
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作者：
Minki Kim;Jungwon Choi
本文提出了一种用于中程高频 (HF) 无线功率传输 (WPT) 系统的自谐振线圈的设计。在 HF、WPT 系统中，两个谐振器之间的临界耦合系数决定了电力传输距离。然而，由于临界耦合系数与耦合线圈的电感值成反比，WPT系统中较长的传输距离需要较高的电感值，这会带来两个主要挑战：（1）固定频率下补偿网络中的小电容（Cs），以及（2）由于每个耦合线圈中的寄生电容（Cp）导致的低寄生谐振频率。为了克服这些问题，我们首先设计并制造了优化的自谐振线圈，以在 10 MHz 频率下无需任何外部电容器即可实现更长的传输距离。自谐振线圈由两个相同的螺旋线圈组成，它们之间的距离产生串联电容$(C_{s})$，无需任何额外元件。所提出的自谐振线圈设计解决了电容器击穿问题，并使我们能够轻松地调整线圈。 Cs 值是使用线圈的等效模型（例如 $R、L$ 和 Cp）来选择的，用于 WPT 条件下的谐振。此外，所提出的自谐振线圈设计提供了另一种设计，通过调整 Cs 值来维持特定过耦合条件下的零相位角 (ZPA)。我们在160 cm直径和13.56 MHz下设计了三种具有不同临界耦合系数的自谐振线圈。在 180 W AC-to-AC WPT 条件下，这些系统中三种类型线圈的转换效率约为 96%。通过考虑Cp值调整Cs值并在保持高电感值的同时增加传输距离，设计的自谐振线圈在没有任何额外电容器的情况下成功运行。
This paper presents a design of self-resonant coils for mid-range, high-frequency (HF) wireless power transfer (WPT) systems. In HF, WPT systems, a critical coupling coefficient between two resonators determines the power transmission distance. However, because the critical coupling coefficient is inversely proportional to the inductance value of the coupling coils, the longer transmission distance in the WPT systems requires a high inductance value, which causes two major challenges: (1) the small capacitance (Cs) in the compensation network at the fixed frequency, and (2) the low parasitic-resonant frequency due to the parasitic capacitance (Cp) in each coupling coil. To overcome these issues, first, we designed and fabricated the optimized self-resonant coils to achieve a longer transmission distance without any external capacitors at 10’s of MHz frequencies. The self-resonant coil consists of two identical spiral coils, and the distance between them creates the series capacitance $(C_{s})$ without any additional components. The proposed self-resonance coil design addresses the capacitor breakdown issue and allows us to tune the coil easily. The Cs value was selected using the coil’s equivalent model such $R, L$, and Cp for the resonance in the WPT condition. In addition, the proposed self-resonant coil design provides the alternative design to maintain the zero-phase angle (ZPA) for the specific over-coupled condition by adjusting the Cs value. We designed the three types of self-resonant coils with different critical coupling coefficients in 160 cm diameter and 13.56 MHz. The conversion efficiencies of the three types of coils were around 96% in these systems under the 180 W AC-to-AC WPT condition. The designed self-resonant coil successfully operated without any additional capacitor by tuning the Cs value considering Cp value and increasing the transmission distance while keeping the inductance value high.