scholarly journals A 3D wireless charging cube with externally enhanced magnetic field for extended range of wireless power transfer

2019 ◽  
Vol 6 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Qi Zhu ◽  
Hua Han ◽  
Mei Su ◽  
Aiguo Patrick Hu

More mobile devices such as mobile phones and robots are wirelessly charged for convenience, simplicity, and safety, and it would be desirable to achieve three-dimensional (3D) wireless charging with high spatial freedom and long range. This paper proposes a 3D wireless charging cube with three orthogonal coils and supporting magnetic cores to enhance the magnetic flux outside the cube. The proposed system is simulated by Ansoft Maxwell and implemented by a downsized prototype. Both simulation and experimental results show that the magnetic cores can strengthen the magnitude of B-field outside the cube. The final prototype demonstrates that the power transfer distance outside the cube for getting the same induced electromotive force in the receiver coil is extended approximately by 50 mm using magnetic cores with a permeability of 2800. It is found that the magnitude of B-field outside the cube can be increased by increasing the width and the permeability of the magnetic cores. The measured results show that when the permeability of the magnetic cores is fixed, the induced electromotive force in the receiver coil at a point 300 mm away from the center of the cube is increased by about 2V when the width of the magnetic cores is increased from 50 to 100 mm. The increase in the induced electromotive force at an extended point implies a greater potential of wireless power transfer capability to the power pickup.

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 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.


2016 ◽  
Vol 3 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Qingfeng Xia ◽  
Longyang Yan

Battery-powered wireless sensor networks have been extensively deployed in condition monitoring and structural health monitoring systems, but the performance of wireless sensors are limited by battery capacity and difficulty of application in rotating machines. In this paper, a variety of commercial wireless charging solutions and coil-shaft configurations for magnetic coupling are compared, having in mind of the application of continuously charging wireless sensors on rotating machines. For the co-axial configuration of the transmitter coil and the receiver coil, a Qi standard compliant wireless charging kit and a custom charging circuit are successfully applied to charge wireless sensors on small rotating test rigs. In order to harvest and store intermittent energy input from the wireless power source, a prototype receiver circuit using a supercapacitor and low-dropout regulator is designed and validated. Based on the prototype circuit, the radial configuration of single transmitter coil and multiple receiver coils is demonstrated for wireless power transfer to the sensor nodes on the drivetrain of a small wind turbine test rig.


2021 ◽  
Vol 214 (4) ◽  
Author(s):  
Osamu Shimizu ◽  
Takashi Utsu ◽  
Hiroshi Fujimoto ◽  
Daisuke Gunji ◽  
Isao Kuwayama

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2209 ◽  
Author(s):  
Jie Wu ◽  
Lizhong Bie ◽  
Nan Jin ◽  
Leilei Guo ◽  
Jitao Zhang ◽  
...  

In wireless charging devices, a transmitter that applies a single inverter to output dual-frequency can effectively solve the charging incompatibility problem caused by different wireless charging standards and reduce the equipment volume. However, it is very difficult to solve the switching angle of the modulated dual-frequency waveform, which involves non-linear high-dimensional multi-objective optimization with multiple constraints. In this paper, an improved differential evolution (DE) algorithm is proposed to solve the transcendental equations of switching angle trains of dual-frequency programmed harmonic modulation (PHM) waveform. The proposed algorithm maintains diversity while preserving the elites and improves the convergence speed of the solution. The advantage of the proposed algorithm was verified by comparing with non-dominated sorting genetic algorithm II (NSGA II) and multi-objective particle swarm optimization (MOPSO). The simulation and experimental results validate that the proposed method can output dual-frequency with a single inverter for wireless power transfer (WPT).


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