Revisiting Two-Port Network Analysis for Wireless Power Transfer (WPT) Systems

In conventional inductive wireless power devices, the energy is transferred via only reactive near fields, which is equivalent to nonradiative Förster energy transfer in optics. Radiation from transmitting and receiving coils is usually considered as a parasitic effect that reduces the power-transfer efficiency. As long as the distance between the two antennas is small compared to the antenna size, conventional wireless power-transfer devices offer rather high power-transfer efficiency, of the order of 80%-90%. However, for larger distances, the transfer efficiency dramatically drops, making such devices impractical. In this paper, we develop a dynamic theory of wireless power transfer between two small loop antennas, clarify the role of far-field radiation, and find a possibility to realize efficient wireless power transfer at large distances utilizing the regime of radiation suppression due to optimized mutual dynamic interactions between the transmitting and receiving antennas. The analytical results are validated by simulations and measurements, and they open a possibility to greatly expand the range of distances of compact wireless power-transfer devices. The developed theory can also be applied to coupling between antennas of different types and to energy transfer between nano-objects.

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“…This result generalizes expressions in Ref. [26], taking into account dynamic interactions between TX and RX antennas. Substituting Eqs.…”

Section: ∂Pte ∂Xsupporting

confidence: 86%

Effective Midrange Wireless Power Transfer with Compensated Radiation Loss

et al. 2023

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“…Equation ( 2), derived from [56], is valid when the coupling is low, i.e., when the mutual impedance is much lower than the real parts of both input impedances, and is, therefore, valid for low values of the PTE. Due to the large separation of 200 mm between Tx and Rx, this approximation is justified.…”

Section: Pte In a Two-port Networkmentioning

confidence: 99%

Optimal Frequency and Wireless Power Budget for Miniature Receivers in Obese People

Van de Steene,

Tanghe,

Martens

et al. 2023

Sensors

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This study investigates wireless power transfer for deep in-body receivers, determining the optimal frequency, power budget, and design for the transmitter and receiver. In particular, the focus is on small, in-body receivers at large depths up to 20 cm for obese patients. This enables long-term monitoring of the gastrointestinal tract for all body types. Numerical simulations are used to investigate power transfer and losses as a function of frequency and to find the optimal design at the selected frequency for an obese body model. From all ISM-frequencies in the investigated range (1 kHz–10 GHz), the value of 13.56 MHz yields the best performance. This optimum corresponds to the transition from dominant copper losses in conductors to dominant losses in conductive tissue. At this frequency, a transmitting and receiving coil are designed consisting of 12 and 23 windings, respectively. With a power transfer efficiency of 2.70×10−5, 18 µW can be received for an input power of 0.68 W while still satisfying exposure guidelines. The power transfer is validated by measurements. For the first time, efficiency values and the power budget are reported for WPT through 20 cm of tissue to mm sized receivers. Compared to WPT at higher frequencies, as commonly used for small receivers, the proposed system is more suitable for WPT to large depths in-body and comes with the advantage that no focusing is required, which can accommodate multiple receivers and uncertainty about receiver location more easily. The received power allows long-term sensing in the gastrointestinal tract by, e.g., temperature, pressure, and pH sensors, motility sensing, or even gastric stimulation.

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“…The high-frequency inverter is suitable for powering multi-MHz WPT systems. Class-E and Class-D amplifier topologies that work at MHz frequencies have been discussed in the literature [11][12][13][14][15] . In Class-D amplifier design, the input voltage is square which does not consider the off time, further very important to high frequencies applications.…”

Section: Introductionmentioning

confidence: 99%

Modeling High Frequency 13.56 MHz Full Bridge Inverter Based on GaN MOSFET for EV Wireless Charging System

Meiyanto Eko Sulistyo,

Gustav Lukman Adhi Pradhityo,

Muharam

et al. 2023

Evergreen

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This paper presents a modelling of a high-frequency full bridge inverter for wireless power transmission (WPT) in Electric Vehicle (EV) charging applications. The inverter is designated at an operating frequency as high as 13.56 MHz in line with regulations for the industrial, scientific, and medical radio band (ISM band). Since the power is transferred wirelessly from the source to the EV, a coupling capacitive was used as a transmitter and receiver of the system. In this paper, the inverter model was simulated and analysed using LTSpice software. Different load changes and power are injected into the system. Furthermore, in order to obtain a robust system, the switching frequency of 13.56 MHz is used with some Dead Time (DT). The system already uses GaN MOSFETs for reliability and performance at high frequencies, in addition to LC impedance matching. The result is that by operating at a resonant frequency of 13.56 MHz with a resistive load of 50, it is obtained with a power of 2.3 kW that has been successfully transmitted with an efficiency of 89%.

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Revisiting Two-Port Network Analysis for Wireless Power Transfer (WPT) Systems

Cited by 14 publications

References 9 publications

Effective Midrange Wireless Power Transfer with Compensated Radiation Loss

Effective Midrange Wireless Power Transfer with Compensated Radiation Loss

Optimal Frequency and Wireless Power Budget for Miniature Receivers in Obese People

Modeling High Frequency 13.56 MHz Full Bridge Inverter Based on GaN MOSFET for EV Wireless Charging System

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