scholarly journals Wireless Power Transfer between Two Self-Resonant Coils over Medium Distance Supporting Optimal Impedance Matching Using Ferrite Core Transformers

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8540
Author(s):  
Jinwook Kim ◽  
Do-Hyeon Kim ◽  
Jieun Kim ◽  
Young-Jin Park
Keyword(s):  
Equivalent Circuit ◽  
Impedance Matching ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Q Factor ◽  
Power Transfer ◽  
Wireless Power ◽  
Ferrite Core ◽  
Matching Conditions ◽  
Power Transfer Efficiency

An efficient wireless power transfer (WPT) system is proposed using two self-resonant coils with a high-quality factor (Q-factor) over medium distance via an adaptive impedance matching network using ferrite core transformers. An equivalent circuit of the proposed WPT system is presented, and the system is analyzed based on circuit theory. The design and characterization methods for the transformer are also provided. Using the equivalent circuit, the appropriate relation between turn ratio and optimal impedance matching conditions for maximum power transfer efficiency is derived. The optimal impedance matching conditions for maximum power transfer efficiency according to distance are satisfied simply by changing the turn ratio of the transformers. The proposed WPT system maintains effective power transfer efficiency with little Q-factor degradation because of the ferrite core transformer. The proposed system is verified through experiments at 257 kHz. Two WPT systems with coupling efficiencies higher than 50% at 1 m are made. One uses transformers at both Tx and Rx; the other uses a transformer at Tx only while a low-loss coupling coil is applied at Rx. Using the system with transformers at both Tx and Rx, a wireless power transfer of 100 watts (100-watt light bulb) is achieved.

scholarly journals Study on impedance matching and maximum wireless power transfer efficiency of circuits with resonant coupling based on simplified S-matrix

2019 ◽  
Vol 16 (11) ◽  
pp. 20190156-20190156 ◽  
Author(s):  
Hiroya Andoh ◽  
Keita Tsuzuki ◽  
Dai Oikawa ◽  
Toko Sugiura ◽  
Takehiko Tsukamoto ◽  
...  
Keyword(s):  
Impedance Matching ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Resonant Coupling ◽  
Power Transfer Efficiency

scholarly journals Analysis of Fundamental Differences between Capacitive and Inductive Impedance Matching for Inductive Wireless Power Transfer

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 476 ◽  
Author(s):  
Yelzhas Zhaksylyk ◽  
Einar Halvorsen ◽  
Ulrik Hanke ◽  
Mehdi Azadmehr
Keyword(s):  
Magnetic Resonance ◽  
Impedance Matching ◽  
Perfect Match ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Power Transfer Efficiency ◽  
Parameter Ranges ◽  
Smith Chart

Inductive and capacitive impedance matching are two different techniques optimizing power transfer in magnetic resonance inductive wireless power transfer. Under ideal conditions, i.e., unrestricted parameter ranges and no loss, both approaches can provide the perfect match. Comparing these two techniques under non-ideal conditions, to explore fundamental differences in their performance, is a challenging task as the two techniques are fundamentally different in operation. In this paper, we accomplish such a comparison by determining matchable impedances achievable by these networks and visualizing them as regions of a Smith chart. The analysis is performed over realistic constraints on parameters of three different application cases both with and without loss accounted for. While the analysis confirms that it is possible to achieve unit power transfer efficiency with both approaches in the lossless case, we find that the impedance regions where this is possible, as visualized in the Smith chart, differ between the two approaches and between the applications. Furthermore, an analysis of the lossy case shows that the degradation of the power transfer efficiencies upon introduction of parasitic losses is similar for the two methods.

scholarly journals Optimization of Multiresonant Wireless Power Transfer Network Based on Generalized Coupled Matrix

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Zhao ◽  
Anna Wang
Keyword(s):  
Optimization Algorithm ◽  
High Efficiency ◽  
Impedance Matching ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Transfer Efficiency ◽  
Transfer Model ◽  
Power Transfer ◽  
Wireless Power ◽  
Power Transfer Efficiency

Magnetic coupling resonant wireless power transfer network (MCRWPTN) system can realize wireless power transfer for some electrical equipment real-time and high efficiency in a certain spatial scale, which resolves the contradiction between power transfer efficiency and the power transfer distance of the wireless power transfer. A fully coupled resonant energy transfer model for multirelay coils and ports is established. A dynamic adaptive impedance matching control based on fully coupling matrix and particle swarm optimization algorithm based on annealing is developed for the MCRWPTN. Furthermore, as an example, the network which has twenty nodes is analyzed, and the best transmission coefficient which has the highest power transfer efficiency is found using the optimization algorithm, and the coupling constraints are considered simultaneously. Finally, the effectiveness of the proposed method is proved by the simulation results.

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.

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