scholarly journals Enhancing the Stability of Medium Range and Misalignment Wireless Power Transfer System by Negative Magnetic Metamaterials

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5695
Author(s):  
Songcen Wang ◽  
Cheng Jiang ◽  
Xiong Tao ◽  
Feng Chen ◽  
Cancan Rong ◽  
...  
Keyword(s):  
Sharp Decrease ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Lateral Migration ◽  
Wireless Power ◽  
Angle Variation ◽  
Electromagnetic Simulations ◽  
The Stability ◽  
Electromagnetic Metamaterials

The misalignment of the resonant coils in wireless power transfer (WPT) systems causes a sharp decrease in transfer efficiency. This paper presents a method which improves the misalignment tolerance of WPT systems. Based on electromagnetic simulations, the structural unit parameters of the electromagnetic material were extracted, and an experimental prototype of a four-coil WPT system was built. The influence of electromagnetic metamaterials on the WPT system under the conditions of lateral misalignment and angular offset was investigated. Experiments showed that the transfer efficiency of the system could be maintained above 45% when the transfer distance of the WPT system with electromagnetic metamaterials was 1 m and the resonant coils were shifted laterally within one coil diameter. Furthermore, the system transfer efficiency could be stabilized by more than 40% within an angle variation range of 70 degrees. Under the same conditions, the transfer efficiency of a system without electromagnetic metamaterials was as low as 30% when lateral migration occurred, and less than 25% when the angle changed. This comparison shows that the stability of the WPT system loaded with electromagnetic metamaterials was significantly enhanced.

scholarly journals Maximizing Transfer Efficiency with an Adaptive Wireless Power Transfer System for Variable Load Applications

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1417
Author(s):  
Jung-Hoon Cho ◽  
Byoung-Hee Lee ◽  
Young-Joon Kim
Keyword(s):  
Loading Condition ◽  
Wireless Power Transfer ◽  
Input Voltage ◽  
Transfer Efficiency ◽  
Maximum Efficiency ◽  
Variable Load ◽  
Power Transfer ◽  
Wireless Power ◽  
Variable Loading ◽  
Power Transfer Efficiency

Electronic devices usually operate in a variable loading condition and the power transfer efficiency of the accompanying wireless power transfer (WPT) method should be optimizable to a variable load. In this paper, a reconfigurable WPT technique is introduced to maximize power transfer efficiency in a weakly coupled, variable load wireless power transfer application. A series-series two-coil wireless power network with resonators at a frequency of 150 kHz is presented and, under a variable loading condition, a shunt capacitor element is added to compensate for a maximum efficiency state. The series capacitance element of the secondary resonator is tuned to form a resonance at 150 kHz for maximum power transfer. All the capacitive elements for the secondary resonators are equipped with reconfigurability. Regardless of the load resistance, this proposed approach is able to achieve maximum efficiency with constant power delivery and the power present at the load is only dependent on the input voltage at a fixed operating frequency. A comprehensive circuit model, calculation and experiment is presented to show that optimized power transfer efficiency can be met. A 50 W WPT demonstration is established to verify the effectiveness of this proposed approach.

Wireless Power Transfer Systems via Strong Coupled Magnetic Resonances — Design, PCB Implementation and Tests

2011 ◽  
Vol 383-390 ◽  
pp. 5984-5989
Author(s):  
Yan Ping Yao ◽  
Hong Yan Zhang ◽  
Zheng Geng
Keyword(s):  
Printed Circuit Board ◽  
Experimental System ◽  
Wireless Power Transfer ◽  
Circuit Board ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Power Transfer Efficiency ◽  
Coil Winding ◽  
Magnetic Resonances

In this paper, we present theoretical analysis and detailed design of a class of wireless power transfer (WPT) systems based on strong coupled magnetic resonances. We established the strong coupled resonance conditions for practically implementable WPT systems. We investigated the effects of non-ideal conditions presented in most practical systems on power transfer efficiency and proposed solutions to deal with these problems. We carried out a design of WPT system by using PCB (Printed Circuit Board) antenna pair, which showed strong coupled magnetic resonances. The innovations of our design include: (1) a new coil winding pattern for resonant coils that achieves a compact space volume, (2) fabrication of resonant coils on PCBs, and (3) integration of the entire system on a pair of PCBs. Extensive experiments were performed and experimental results showed that our WPT system setup achieved a guaranteed power transfer efficiency 14% over a distance of two times characteristic length(44cm). The wireless power transfer efficiency in this PCB based experimental system was sufficiently high to lighten up a LED with a signal generator.

scholarly journals A Modified Wireless Power Transfer System for Medical Implants

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1890 ◽  
Author(s):  
Yosra Ben Fadhel ◽  
Sana Ktata ◽  
Khaled Sedraoui ◽  
Salem Rahmani ◽  
Kamal Al-Haddad
Keyword(s):  
Form Factor ◽  
Wireless Power Transfer ◽  
The Body ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Medical Implants ◽  
Wireless Power ◽  
Small Form ◽  
Power Transfer Efficiency ◽  
Small Form Factor

Wireless Power Transfer (WPT) is a promising technique, yet still an experimental solution, to replace batteries in existing implants and overcome the related health complications. However, not all techniques are adequate to meet the safety requirements of medical implants for patients. Ensuring a compromise between a small form factor and a high Power Transfer Efficiency (PTE) for transcutaneous applications still remains a challenge. In this work, we have used a resonant inductive coupling for WPT and a coil geometry optimization approach to address constraints related to maintaining a small form factor and the efficiency of power transfer. Thus, we propose a WPT system for medical implants operating at 13.56 MHz using high-efficiency Complementary Metal Oxide-Semiconductor (CMOS) components and an optimized Printed Circuit Coil (PCC). It is divided into two main circuits, a transmitter circuit located outside the human body and a receiver circuit implanted inside the body. The transmitter circuit was designed with an oscillator, driver and a Class-E power amplifier. Experimental results acquired in the air medium show that the proposed system reaches a power transfer efficiency of 75.1% for 0.5 cm and reaches 5 cm as a maximum transfer distance for 10.67% of the efficiency, all of which holds promise for implementing WPT for medical implants that don’t require further medical intervention, and without taking up a lot of space.

scholarly journals Circuit Model and Analysis of Multi-Load Wireless Power Transfer System Based on Parity-Time Symmetry

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3260 ◽  
Author(s):  
Chengxin Luo ◽  
Dongyuan Qiu ◽  
Manhao Lin ◽  
Bo Zhang
Keyword(s):  
Output Power ◽  
Coupling Coefficient ◽  
Power Distribution ◽  
Wireless Power Transfer ◽  
Circuit Model ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Time Symmetry ◽  
Constant Output

In the multi-load wireless power transfer (WPT) system, the output power and transfer efficiency will drop significantly with the change of distance between transmitter and receiver. Power distribution among multiple loads is also a major challenge. In order to solve these problems, a novel multi-load WPT system based on parity–time symmetry (PT-WPT) is proposed in this paper. Firstly, the multi-load PT-WPT system is modeled based on the circuit model. Then, the transmission characteristics of the multi-load PT-WPT system are analyzed. It is found that constant output power with constant transfer efficiency can be maintained against the variation of coupling coefficient, and the power distribution relationship among loads is only related to the coupling coefficient. Further, power distribution under different coupling situations is analyzed in detail to meet different power demands. Finally, taking a dual-load PT-WPT system as an example, the system parameters are designed and the circuit simulation is carried out. The simulation results are consistent with the theoretical analysis, which shows that PT symmetry can be applied to the multi-load WPT system to achieve constant output power, constant transfer efficiency, and power distribution simultaneously.

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