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1

Research on a novel hybrid shielding structure of magnetic coupler for inductive power transfer system

Liu Yun Rui, Wang Chunfang, Xia Dongwei, Yue Rui

Archives of Electrical Engineering

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2021

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Vol. 70, nr 1

129--143

EN

With the development of wireless power transfer technology, more and more attention has been paid to its electromagnetic safety. In this paper, a novel hybrid shielding structure composed of the innermost fan-shaped ferrite, the interlayer nanocrystalline stripand the outermost aluminum foil is proposed to shield the electromagnetic field of the inductive power transfer system. Eight structure parameters of the proposed shielding areoptimized by finite element simulation, in order to reduce the magnetic leakage of the system and improve the utilization rate of shielding materials. In addition, the proposed structure is compared with two types of typical double-layer hybrid shielding from the perspectives of the weight, the coupling coefficient and the magnetic flux leakage. Both simulation and experiment results show that the cost and weight of the proposed shield are about 60% lower than the traditional disk shield. More over, the shielding layer proposed in this paper can not only effectively reduce the magnetic flux leakage of the system, but also maintain a high coupling coefficient.

2

Nanocrystallines as core materials for contactless power transfer (CPT)

Ghosh P. C., Sadhu P. K., Ghosh A., Pal N.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

20--29

EN

Efficient contactless power transfer (CPT) is an emerging technology which is attracting great scientific interest because it can mitigate some of the problems commonly associated with conventional wired power transfer systems. CPT systems suffer from very low efficiency because of the poor coupling coefficient, which is due to the large air gap between the transmitter and receiver coils. Therefore, CPT transformers are mostly operated at high frequencies to improve the quality factor of transmitter and receiver coils and thus counterbalance the effect of the low coupling coefficient. On the other hand, informed selection and design of core materials for CPT transformers can improve the coupling coefficient and thereby boost the overall power transfer efficiency of the system. However, at high power and high frequency CPT applications, core losses become very high and play an important role in determining the efficiency of the system. This paper reports on a detailed investigation into the suitability of nanocrystallines as core materials for high power and high frequency CPT systems.

3

Investigation and Study of Mode Splitting in Near Field Inductive Communication Systems

Thanh H. D., Agbinya J. I.

International Journal of Electronics and Telecommunications

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2013

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Vol. 59, No. 2

185-194

EN

Frequency splitting is a near field inductive communication phenomenon where the resonant frequency divides into many separate frequencies or to different modes. In this paper, we show that this phenomenon depends on the coupling coefficients or the natural response of the circuit by using the circuit theory to derive these splitting frequencies. Also, the rules for the general matrix that is used to solve for splitting frequencies are also demonstrated clearly. Mode splitting is observed for peer-to-peer, three coils and four coil systems due to the existence of the nearest and second neighbour interactions. In particular, two, three and four modes have been analysed for two, three, and four coil systems respectively. However, the number of modes for these systems can be changed according to the degree of coupling. The differences in the resultant splitting frequencies with and without the second neighbour interaction are shown in the simulation results. Furthermore, we assess the system performances regarding to power efficiency through the inductive transfer functions. Besides, either coupling coefficients at resonance or the simplified transfer functions in some specific scenarios can be obtained by having an insight into these transfer functions. Finally, we recognise and propose that splitting frequency phenomenon can be deployed to transmit signals at many frequencies concurrently.

4

Simplified coupling power model for fibers fusion

Saktioto J., Ali J., Fadhali M.

Opto-Electronics Review

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2009

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Vol. 17, No. 3

193-199

EN

Fiber coupler fabrication used for an optical waveguide requires lossless power for an optimal application. The previous research coupled fibers were successfully fabricated by injecting hydrogen flow at 1 bar and fused slightly by unstable torch flame in the range of 800-1350°C. Optical parameters may vary significantly over wide range physical properties. Coupling coefficient and refractive index are estimated from the experimental result of the coupling ratio distribution from 1% to 75%. The change of geometrical fiber affects the normalized frequency V even for single mode fibers. V is derived and some parametric variations are performed on the left and right hand side of the coupling region. A partial power is modelled and derived using V, normalized lateral phase constant u, and normalized lateral attenuation constant, w through the second kind of modified Bessel function of the l order, which obeys the normal mode and normalized propagation constant b. Total power is maintained constant in order to comply with the energy conservation law. The power is integrated through V, u, and w over the pulling length of 7500 µm for 1-D. The core radius of a fiber significantly affects V and power partially at coupling region rather than wavelength and refractive index of core and cladding. This model has power phenomena in transmission and reflection for an optical switch and tunable filter.

5

Electromagnetic modelling of 3D periodic structure containing magnetized or polarized ellipsoids

Koledintseva M. Y.

Opto-Electronics Review

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2006

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Vol. 14, No. 3

253-262

EN

Coupling matrix and coupling coefficient concepts are applied to the interaction of an incident plane wave with a regular array of small magnetized or polarized ellipsoids, placed in a homogeneous surrounding medium. In general case, the angle of incidence and polarization of the plane wave upon an array of ellipsoids can be arbitrary. In this model, it is assumed that all the ellipsoids are the same, and the direction of their magnetization is also the same. The direction of magnetization is arbitrary with respect to the direction of the propagation of the incident wave and to the boundary plane between the first medium, where the incident wave comes from, and the array material under study. Any magnetized or polarized ellipsoid is represented as a system of three orthogonal elementary magnetic radiators (EMR) and/or three orthogonal elementary electric radiators (EER). Mutual interactions of individual radiators in the array through the incident plane wave and corresponding scattered electromagnetic fields are taken into account. The electrodynamic characteristics - reflection from the surface of the semi-infinite array (in particular, containing uniaxial hexagonal ferrite resonators), transmission through the array, and absorption are analyzed.