scholarly journals Wireless Power Transfer Systems Optimization Using Multiple Magnetic Couplings

Electronics ◽  
2021 ◽  
Vol 10 (20) ◽  
pp. 2463
Author(s):  
Dragoș Marin Niculae ◽  
Marilena Stanculescu ◽  
Sorin Deleanu ◽  
Mihai Iordache ◽  
Lavinia Bobaru

Multiple magnetic couplings used to increase the link distance in wireless power transfer systems (WPTSs) are not new. An efficient power transfer in conditions of an extended link distance requires a series connection of the intermediate coils. However, all four connections of the emitter and receiver coils are equally possible. This present paper conducts an extensive analysis of WPTSs utilizing three magnetic couplings. The type of connection of the emitter and receiver coils represented the criterion utilized for the WPTS optimization assessment. The first step requires the determination of the schematic of the sinusoidal equivalent circuit. Then, one synthesizes the functions describing the system performances (e.g., the amount of delivered active power or efficiency) by applying the entirely symbolic and or the hybrid symbolic-numerical formalism. The output of such functions consists of appropriate representation in the frequency domain, based upon Laplace state variable equations (SVE) or complex or Laplace modified nodal equations (MNE). The dependency of the WPTS performance on the number of magnetic couplings and their parameters included a study on resistive loss minimization. The minimization applies to the intermediate coils, whereas the outcomes are the active delivered power and the power transfer efficiency—the first study case aimed at a comparison between two distinct WPTSs: three magnetic couplings versus two. The second case of the study compared the WPTSs having a series connection of three magnetic couplings with those built with the emitter-receiver resonators in parallel. One determined the normalized sensitivities as frequency functions, which depend on circuit resistances, load resistance and the coupling factor between the second and the third coil. The optimization algorithms are suitable for computing optimal parameters of the given circuit to ensure maximum and minimum values of the performance value. Good simulation examples followed the proposed optimization techniques.

2015 ◽  
Vol 7 (3-4) ◽  
pp. 349-359 ◽  
Author(s):  
Alessandra Costanzo ◽  
Marco Dionigi ◽  
Franco Mastri ◽  
Mauro Mongiardo ◽  
Johannes A. Russer ◽  
...  

A novel approach for the rigorous design of magnetic resonant wireless power transfer links is introduced. We show how, starting from two coupled inductors and making use of general network theory, it is possible to derive analytic rules for designing the source and load terminations which provide the maximum power transfer efficiency or maximize the received power. We also show that, by adding suitable matching networks to two coupled inductors we can realize a wireless link acting as a 1:n transformer and having the all required tunable reactive elements on the primary side. The proposed topology greatly simplifies the design, since only an inductive coil and a fixed capacitance are required on the secondary side; in addition, when tuning is required due to coils misalignment or to link distance variation, it can be attained by acting on the transmitter side without the need for a feedback communication through the link. Moreover, when the load resistance is designed for maximum output power, its value is fixed and does not depend on the coupling. A numerical and experimental verification of the proposed approach is also presented.


Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7277
Author(s):  
SangWook Park ◽  
Seungyoung Ahn

This study presents an equivalent circuit model for the analysis of wireless power transfer (WPT) through both electric and magnetic couplings using merely a resonant coupler. Moreover, the frequency split phenomenon, which occurs when transmitting couplers are near receiving couplers, is explained. This phenomenon was analyzed using simple circuit models derived via a mode decomposition technique. To verify the proposed method, a resonant coupler using mixed coupling was designed and its efficiency was compared with the result obtained using a commercial electromagnetic solver. The results of this study are expected to aid in designing various WPT couplers or sensor antennas by selecting electric, magnetic, or mixed couplings. Furthermore, the results of this study are expected to be applied to technologies that sense objects, or simultaneously transmit and receive information and power wirelessly.


2013 ◽  
Vol 846-847 ◽  
pp. 893-897
Author(s):  
Hua Xi Wen ◽  
Xian Gu ◽  
Dong Fang ◽  
De Dong Ding ◽  
Qiang Yu ◽  
...  

The inductive wireless power transfer efficiency is determined by the coupling factor and coil quality factors. This paper studies the coupling factor of an inductive power link (IPL) for wireless power transfer in advanced brain-machine interface applications. By comparison to the experimental results, the various design tools including Maxwell simulation and two analytical models are evaluated for prediction of the coupling factor. The coupling factors of IPLs with different design parameters are also analyzed. The results show that for specific wireless power transfer distances, the coupling factor of an IPL is mainly related to the size and fill ratio of the coils, while is almost independent of the coil track pitch, coil width/pitch ratio, and track thickness.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4975
Author(s):  
Jacek Maciej Stankiewicz ◽  
Agnieszka Choroszucho

In the article, a wireless charging system with the use of periodically arranged planar coils is presented. The efficiency of two wireless power transfer (WPT) systems with different types of inductors, i.e., circular and square planar coils is compared, and two models are proposed: analytical and numerical. With the appropriate selection of a load resistance, it is possible to obtain either the maximum efficiency or the maximum power of a receiver. Therefore, the system is analyzed at two optimum modes of operation: with the maximum possible efficiency and with the highest power transmitted to the load. The analysis of many variants of the proposed wireless power transfer solution was performed. The aim was to check the influence of the geometry of the coils and their type (circular or square) on the efficiency of the system. Changes in the number of turns, the distance between the coils (transmit and receive) as well as frequency are also taken into account. The results obtained from analytical and numerical analysis were consistent; thus, the correctness of the adopted circuit and numerical model (with periodic boundary conditions) was confirmed. The proposed circuit model and the presented numerical approach allow for a quick estimate of the electrical parameters of the wireless power transmission system. The proposed system can be used to charge many receivers, e.g., electrical cars on a parking or several electronic devices. Based on the results, it was found that the square coils provide lower load power and efficiency than compared to circular coils in the entire frequency range and regardless of the analyzed geometry variants. The results and discussion of the multivariate analysis allow for a better understanding of the influence of the coil geometry on the charging effectiveness. They can also be valuable knowledge when designing this type of system.


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

<p>Wireless power transfer (WPT) system has got significant attention in recent years due to its applications in consumer electronics, medical implants and electric vehicles etc. WPT is a promising choice in situations, where the physical connectors can be unreliable and susceptible to failure. The efficiency of WPT system decreasing rapidly with increasing air-gap. Many circuit topologies have been employed to enhance the efficiency of the WPT system. This paper presents the modelling and performance analysis of resonant wireless power transfer (RWPT) system using series-parallel-mixed topology. The power transfer efficiency analysis of the model is investigated via circuit theory. S-parameters have been used for measuring power transfer efficiency. Transient analysis is performed to realize the behavior of voltage and current waveforms using advanced design system (ADS) software. The proposed model is tested with two amplitudes i.e. 100 V peak-to-peak and 110 V peak-to-peak at the same frequency of 365.1 kHz. The overall result shows that the series-parallel-mixed topology model has higher efficiency at low coupling factor (K) for both voltage amplitudes.</p>


Author(s):  
Quandi Wang ◽  
Yingcong Wang ◽  
Jianwei Kang ◽  
Wanlu Li

Purpose The purpose of this paper is to present a monitoring method for a three-coil wireless power transfer (WPT) system, which consists of a transmitting coil (Tx), a relay coil and a movable receiving coil (Rx). Both an ideal resistance and a rectifier bridge load are taken into account. Design/methodology/approach From the perspective of fundamental component, the equivalent impedance of a rectifier bridge load is well analyzed. On the basis of the circuit model of a three-coil WPT, estimation equations of the variable mutual inductances and load condition are deduced. Multi-frequency input impedance obtained by frequency scans combined with the Newton-Raphson method are used to obtain solutions. Findings Experimental results indicate that the estimated parameter values are close to each other when different sets of source frequencies are applied. When compared with simulation results, these estimated parameters including both mutual inductances and load resistances are found to be accurate. Originality/value Using only the information of input side, the proposed algorithm can estimate the mutual inductances and load resistance regardless of the Rx positions. Estimation is feasible for the system with a rectifier bridge load. The estimated analysis will serve as a key step in load power stabilization for WPT systems.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Longzhao Sun ◽  
Mingui Sun ◽  
Dianguang Ma ◽  
Houjun Tang

In wireless power transfer (WPT) system, the variations in load resistance and mutual inductance influence the output voltage and output current, making the system deviate from its desirable operating condition; hence, it is essential to monitor load resistance and mutual inductance. Using input-side measurement to detect load resistance and mutual inductance has great advantages, because it does not need any direct measurements on the receiving side. Therefore, it can remove sensors on the receiving side and eliminate communication system feeding back the load measurements. This paper investigates load resistance and mutual inductance detection method in series-parallel compensated WPT system. By measuring input current and input voltage, the equation for calculating load resistance is deduced; when the operating frequency is lower than or equal to the receiving-side resonant frequency, the rigorous mathematical derivations prove that load resistance can be uniquely determined by using only one measurement of input current and input voltage. Furthermore, the analytical expressions for identifying load resistance and mutual inductance are deduced. Experiments are conducted to verify the proposed method.


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