Unified Theory of Electromagnetic Induction and Magnetic Resonant Coupling

This paper proposes an optimal coil layout of wireless power transfer (WPT) systems for underwater vehicles (UVs). The power supply station adopts a multicoil arrangement with a double layer, and the UV also uses two receiving coils. The proposed WPT system for UVs has a reasonable advantage, where it does not request to adjust the relative position of coils. This paper experimentally discusses an optimal coil layout based on measurement results of a coupling coefficient. As a result, the proposed coil arrangement with the geometry rule realizes a certain power transfer under any positions and directions of UVs.

Section: Coupling Coefficient Map and Evaluation Methodsmentioning

confidence: 98%

A coil layout of wireless power transfer systems based on multicoil arrangement for underwater vehicles

Sato

Kifune

Komeda

2019

“…Here the same solenoid coils are used on both sides so that magnetic paths #12 and #34 occur in upper and lower parts, respectively, of the transfer coils as shown in Figure 6C. 7 With all windings separated, magnetic paths #1, #2, #3, #4 occur so that the share of paths #12 and #34 is reduced, and k c decreases. However, as windings #1 and #4, #2 and #3 grow apart, main flux declines, and k DAB decreases as well as k c .…”

Section: Implementation Of Proposed Methodsmentioning

confidence: 99%

“…2,3 However, inductive wireless power transfer (IPT) systems that can supply power without electric contact are extensively studied in terms of convenience and protection against electric shock from the charger's housing. [4][5][6][7][8][9] With nonresonant IPT, transmitted power and power factor in AC link heavily depend on the strength of magnetic coupling between primary and secondary windings. 7 In case of weak magnetic coupling, high voltage must be induced in the secondary winding in order to deliver power to a load, which means higher excitation current.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7][8][9] With nonresonant IPT, transmitted power and power factor in AC link heavily depend on the strength of magnetic coupling between primary and secondary windings. 7 In case of weak magnetic coupling, high voltage must be induced in the secondary winding in order to deliver power to a load, which means higher excitation current. Increase in excitation current not contributing to power transmission adds to converter's conduction loss and copper loss in sending and receiving coils, thus impairing system's efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Improvement of equivalent magnetic coupling coefficient of wireless power transfer system with multiwinding transmission coil

Furukawa

Kusaka

Itoh

2019

This article proposes a novel method of improving the overall coupling coefficient of a wireless power transfer system by using a four‐winding transformer of which two pairs of windings each are connected in parallel in the primary side and secondary side. By weakening the coupling coefficients kc between the parallel windings, the overall magnetic coupling between the primary side and secondary side of the transformer is improved. In order to confirm the validity of the proposed method, a conventional high‐kc four‐winding transmission coil and the proposed low‐kc four‐winding transmission coil are experimentally assessed. Then, the coils are introduced into a nonresonant inductive power transfer system utilizing a dual active bridge converter in order to confirm the correction of the input power factor. As a result, the overall magnetic coupling of the proposed four‐winding coils was found to be improved by 17% compared with the overall magnetic coupling of the conventional coil. Moreover, the input power factor for the entire load is corrected with the proposed four‐winding coil. Therefore, a low kc is effective in improving the overall magnetic coupling.

“…Equation (18) includes the capacitor C 2 of the secondary coil. C 2 should be determined so as to maximize efficiency [17]. In other words, when Eq.…”

Section: Transformer Efficiency Optimal Loadmentioning

confidence: 99%

Circuit Analysis and Characterization of Contactless Power Transfer System with Variable Impedance

Yamada

Tsuda

Kobayashi

et al. 2018

SUMMARY A contactless power transfer system using a repeater coil (repeater Coil topology) has been proposed as a method of suppressing overcurrent without power control during misalignment or no‐load. By installing a repeater coil between the primary and secondary coils, it is possible to increase the input impedance in the case of misalignment of the secondary coil or no‐load condition. In addition, another contactless power transfer system using primary parallel and secondary series resonance capacitors (PS capacitor topology) has been proposed. In the PS capacitor topology, the input impedance can be increased during misalignment of the secondary coil or no‐load condition similar to the repeater coil topology. In this paper, we evaluated the characteristics of both these topologies. First, we conducted a circuit analysis of the repeater coil topology and proposed a design method. In addition, we theoretically clarified the characteristic difference of the two topologies and experimentally evaluated the characteristics.