scholarly journals Efficiency investigation of SS and SP compensation topologies for wireless power transfer

Author(s):  
Masood Rehman ◽  
Perumal Nallagownden ◽  
Zuhairi Baharudin

<span>Wireless power transfer (WPT) using inductive and resonant coupling has been widely explored in recent years for ease and safety over conventional cable charging systems. The efficiency of WPT systems is reducing drastically due to an increase in air-gaps and misalignment between transmitter (Tx) and receiver (Rx). Many circuit topologies have been analyzed to improve the efficiency of WPT system based on symmetrical coils. However, the circuit topologies have not been studied widely for unsymmetrical coils. This paper presents the investigation of two fundamental topologies i.e. Series-Series (SS) and Series-Parallel (SP) for unsymmetrical coils as well as symmetrical coils. Theoretical analysis of both the compensation topologies have been accomplished, then modeling of both the topologies have been done using two different combination of circular coils. In first case, two similar size coils have been designed and in second case transmitter coil of higher dimensions than receiver coil is designed. The efficiency of the system has been analyzed at multiple distances in both cases by integrating coil structure with the circuit. The overall result show that when Tx is bigger than Rx, the SP topology gives better efficiency than SS counterpart.</span>

2020 ◽  
Vol 20 (4) ◽  
pp. 270-276
Author(s):  
Nam Ha-Van ◽  
Hoang Le-Huu ◽  
Minh Thuy Le ◽  
Kwangsuk Park ◽  
Chulhun Seo

The free-positioning wireless power transfer (WPT) system has drawn attention in recent years. Traditionally, a WPT system can transfer energy in one or two directions on the same plane, but it leads the restrictions of angle and axis misalignment between a transmitter and a receiver coil. In this paper, we propose a free-positioning WPT system using a three-dimensional cubic-shaped transmitting coil for portable device charging. A small receiving coil is placed inside the transmitter to achieve the transferred energy through the magnetic resonant coupling. In addition, the equivalent circuit and the mutual inductance between the Tx and Rx coils are analyzed. Finally, a practical experiment is implemented to verify the transfer performance, which can reach up to about 50% power transfer efficiency. The proposed system can charge in spatial freedom.


A typical magnetic resonance based wireless power transfer (WPT) system comprises a transmitter coil and an embedded receiver coil used for wireless charging of the electrical and electronics devices. It has been investigated that the coil structure influence the power transfer efficiency of the wireless charging system .The investigations have been carried out in order to determine a suitable coil type and geometry so as to achieve higher efficiency of a wireless power transfer system. The present investigation will afford the design strategy for an efficient wireless charging system .


2019 ◽  
Vol 12 (9) ◽  
pp. 2338-2344
Author(s):  
Kazuhiro Umetani ◽  
Toru Honjo ◽  
Takahiro Koyama ◽  
Masataka Ishihara ◽  
Eiji Hiraki

A Wireless Power Transfer system consists of a transmitter coil which is inductively coupled with secondary coil and is popular for wireless charging of future office communication system. Wireless power transfer is used in different applications ranging from mobile chargers to charging stations. In this paper simulation of Wireless Power Transfer for future office communication systems has been conducted over Maxwell 3d of Ansys electromagnetic suite. The input frequency of primary coil is varied from 1kHz -120kHz with respect to the change in resonant capacitance and observed that input frequency between 20kHz-30 kHz, the output power in secondary coil appears to be maximum at variable distances between transmitter coil and receiver coil. There is an improvement of 72% seen in the output power of secondary coil for 25kHz input frequency of primary coil as compared with 40kHz input frequency. This model can be helpful to design future Office Communication systems for charging the mobile phones, Laptops and to turn on the printer wirelessly.


Author(s):  
A. H. Butar-Butar ◽  
J. H. Leong ◽  
M. Irwanto

A solenoid supplied by alternating current (AC) voltage generates electromagnetic which has a field area depends on the level of supplied voltage and current flows through the solenoid. The electromagnetic filed can be captured by the other solenoid in the field area. This concept can be applied in a wireless power transfer (WPT) as presented in this paper. The WPT has transmitter coil and receiver coil which each has form of solenoid. The transmitter coil is connected a half bridge circuit to generate AC voltage on the transmitter coil which transferred to the receiver coil. In the experimental set up, the receiver coil is supplied by DC voltage source and it is changed to observe its effect on the voltage and current on the transmitter and receiver coil of the WPT system.


2021 ◽  
Vol 58 (1) ◽  
pp. 3477-3488
Author(s):  
Samuel Afoakwa, Kyei Anim, Young-Bae Jung

Wireless power transfer technology via magnetic resonance coupling now has significant interest in industry and research with many applications. This paper proposes a linear multiple transmitter coil array (5 coils) for wireless power transfer for added gain and hence higher transfer efficiency in comparison to a single transmitter coil. The frequency splitting effect as a result of the coupling between the resonant transmitter coils due to their close proximity is shown to reduce the transfer efficiency to a receiver. The effect of the array spacing on splitting effect suppression is verified. It is shown that the splitting effect is sup-pressed as the distance between the coils is increased leading to a higher received signal and hence higher efficiency. Proposed horizontal displacement of the middle transmitter coils (2nd and 4th coils) in the coil array is shown to suppress frequency splitting. To further suppress the splitting effect due to the magnetic coupling between the transmitter coils, a multiple transmitter array is proposed with different coil turns. Thus it is shown that designing the multiple coil array with mixed number of coil turns (the 2nd and 4th coils are designed to have different number of turns as compared to the other three coils) causes uniform coupling among the coils reducing and eventually eliminating the splitting effect. Also to increase the efficiency at the receiver coil, displaced stacked coils are introduced on top of the coil array. The pro-posed stacked coil array is demonstrated to improve the transfer efficiency. Using the techniques, the proposed linear array structure achieves a transfer efficiency of 36.9% for a receiver coil at the boresight of the array at a transfer distance of 40 cm.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 332
Author(s):  
Young Jin Hwang ◽  
Jae Young Jang

Electric vehicle (EVs), which use an electric motor, are expected to replace internal combustion engine vehicles. However, to date EVs are not highly attractive to consumers due to their unsatisfactory battery charging characteristics and high cost. In particular, the existing conductive charging method makes it more difficult to spread EVs due to the inconvenience of charging and the risk of electric shock. The wireless power transfer (WPT) system can eliminate all of the charging troubles of EVs. However, the WPT systems in existing EVs have large air gaps between the transmitter coil and the receiver coil, posing a hurdle that prevents success. The large air gap cause issues such as a loose coupling, low efficiency, and troublesome electromagnetic compatibility (EMC). An in-wheel WPT system can serve as a solution to address the issues arising due to the large air gap. In this paper, we propose a magnetic coupler structure of an in-wheel WPT system for EV applications. A design of two coils is introduced, in which the transmitter coil and receiver coil are designed based on a design method. Moreover, the pad structure according to the ferromagnetic core geometry is designed and discussed. The aim of this research is to find a suitable configuration of the magnetic coupler for an in-wheel WPT system. The values of the coupling coefficients according the magnetic coupler structure are determined. This paper is expected to provide a good reference for further research, including work on the manufacturing of a prototype.


2019 ◽  
Vol 6 (2) ◽  
pp. 85-96
Author(s):  
Minxin Wu ◽  
Wenxing Zhong ◽  
Siew Chong Tan ◽  
S. Y. R. Hui

AbstractThis paper presents a comparative study on three types of slim coil structures used as a three-dimensional (3-D) receiver in a wireless power transfer system with a planar transmitter coil. The mutual coupling values and their variations between the receiver structures and the transmitter coil are compared under different distances and angular orientations with respect to the transmitter coil. The merits of performance are related to the consistency of the mutual coupling values under different orientations in a range of distances from the transmitter coil. The practical results show that slim 3-D receiver coil structures can be compatible with a planar transmitter coil with reasonably high-mutual coupling.


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