Positioning-free magnetically resonant wireless power transmission board with staggered repeater coil array (SRCA)

The signal fading in wireless underground sensor networks (WUSNs), which is caused by lossy media such as soil and sand, can be reduced by applying technology of magnetoinductive (MI) propagation. This technology can effectively establish a communication at very low frequency (VLF). In contrast to the previous studies in the literature, which mostly focus on the propagation of plane waves, we propose a new approach based on the plane wave expansion (PWE) to model the near field MI waves. The proposed approach is based on excitation of a point source, which is a common case in a practical WUSN. The frequent usage of square lattice MI structure is investigated. To verify the mathematical derivation, the simulation of time domain based on the fourth-order Runge-Kutta (RK) method is carried out. Simulation results show that the new model can provide a precise prediction to the MI wave's propagation, with the computation load being one-tenth of that of the time domain simulation. The characteristics of the propagation of the MI waves are presented and discussed. Finally, the reflection on the edge of the MI structure is reduced by analysing the terminal matching conditions and calculating a method for matching impedances.

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“…where left to center is the power flow in direction and is marked with and the down to center is marked with ; thus (20) can be rewritten as…”

Section: Discussionmentioning

confidence: 99%

Propagation Modeling of Point Source Excited Magnetoinductive Waves Based on a New Plane Wave Expansion Approach

Liu

Zhang

Zhu

et al. 2015

Mathematical Problems in Engineering

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“…Depending on the coil arrangement, planar pads are divided into two categories: single-layer and multi-layer pads. In singlelayer pads, most predominantly the source or transmitter coil(s) cover the entire surface of the horizontal field-extenders, actively energizing the whole area [10][11][12][13]. The traditional single-layer planar pad has been improved by introducing multilayer pads.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, multi-layer pads can provide higher magnetic fields. Multi-layer pads can be designed using single layer coils or by interconnecting multi-layered coils [9][10][11][12][13][14], which is a versatile and desirable feature. Multi-layer coils have been reported in [5,[15][16] and a novel approach based on a twolayer system is presented in [9] where the first layer coil can act as an active transmitter and the second layer as a staggered repeater coil system.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, the work around planar pad design focuses on developing a robust planar pad by taking into account the general guidelines developed by researchers throughout the decades about coil design (e.g., indications such as: implementing a hollow approach [18], varying turn-widths for both single and multilayer coils [19], uneven pitches [20] etc.). Existing research focuses more on circular, rectangular and hexagonal coil designs for the development of planar pads [5][6][7][8][9][10][11][12][13][14][15][16][17]. In studies comparing these three coil designs, hexagonal coils exhibit a higher tolerance to misalignment than square coils [21] and circular coils can maintain a higher coupling for the same air-gap than rectangular coils of similar dimensions [22].…”

Section: Introductionmentioning

confidence: 99%

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Extending the horizontal transmission range of an inductive wireless power transfer system using passive elliptical resonators

Alexandru

Zhu

2021

IET Power Electronics

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This paper investigates the development of a passive elliptical planar coil for extending the horizontal transmission distance in an inductive transmitter-receiver wireless-power transfer system (WPT). The passive base coil partially overlaps the transmitter coil and extends the horizontal wireless link between the transmitter and receiver. The base coil models investigated are divided into three categories based on their length. Moreover, for each length category, the optimum number of turns is determined. All proposed models are analysed through the electromagnetic simulation (EMF) software Ansys-Maxwell and Simplorer as well as validated experimentally. For the entire analysis, the maximum efficiency principle is followed in this system. Therefore, impedance matching networks are used across all three terminals in order to tune the system to the operating frequency of 200 kHz to achieve maximum efficiency. The maximum achievable efficiency is determined for each coil prototype (in both simulation and experiment) and the results are compared. The extent to which the EMF software is a valuable tool in developing a planar passive base for an inductive WPT system is discussed. Overall, the proposed concept behind the passive base coil is proved to be successful in extending the horizontal distance between the transmitter and receiver.

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“…In the newly developed magnetically resonant WPTS on a printed circuit board (PCB), however, wireless power transmission efficiency degradation due to a misalignment of the RX coil is still large even if the magnetic resonance is used. In order to Manuscript keep a high efficiency regardless of the misalignment, a staggered repeater coil array (SRCA) is proposed in this letter [6]. By using a WPTS with an SRCA, a positioning of the RX coil is not required, thereby enabling the ubiquitous charging.…”

Section: Introductionmentioning

confidence: 99%

Positioning-Free Resonant Wireless Power Transmission Sheet With Staggered Repeater Coil Array (SRCA)

Mori

Lim

Iguchi

et al. 2012

Antennas Wirel. Propag. Lett.

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A magnetically resonant wireless power transmission sheet (WPTS) on a printed circuit board is developed. WPTS wirelessly supplies the power to electronic devices including the wearable wireless healthcare devices anywhere on the sheet with high efficiency. In order to increase a power transmission efficiency degraded by a misalignment of a receiver coil, a transmitter coil array and a proposed staggered repeater coil array (SRCA) are stacked in WPTS. One transmitter coil closest to the receiver coil and the surrounding four repeater coils are selectively activated based on the result of a position detection of the receiver coil. By adding SRCA to the transmitter coil array, the measured power transmission efficiency at the worst-case misalignment increases from 4.8% to 64% at a distance of 15 mm between the transmitter and receiver coils with a diameter of 40 mm. The measured results are verified by electromagnetic simulations.

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Positioning-free magnetically resonant wireless power transmission board with staggered repeater coil array (SRCA)

Cited by 9 publications

References 5 publications

Propagation Modeling of Point Source Excited Magnetoinductive Waves Based on a New Plane Wave Expansion Approach

Propagation Modeling of Point Source Excited Magnetoinductive Waves Based on a New Plane Wave Expansion Approach

Extending the horizontal transmission range of an inductive wireless power transfer system using passive elliptical resonators

Positioning-Free Resonant Wireless Power Transmission Sheet With Staggered Repeater Coil Array (SRCA)

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