Electric characteristics of capacitors using a conductive transparent film for an application to wireless power transfer

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1305-1313
Author(s):  
Tomoki Watanabe ◽  
Ryota Kato ◽  
Koki Murata ◽  
Shogo Kiryu
Keyword(s):  
Window Glass ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Initial Study ◽  
Power Transfer ◽  
Wireless Power ◽  
Transparent Conductive Film ◽  
Field Coupling ◽  
Conductive Film ◽  
Loss Resistance

Wireless power transfer technologies have been developing in various fields. One method of the wireless power transfer is one using electric field coupling. Capacitors are used in the method. If transparent conductive film as the electrodes are used, electric power can be transfer through a window glass. In this report, as an initial study for a wireless power feeding through a window glass, the electric characteristics of capacitors using a transparent conductive film were investigated. At first, the capacitances and the electric losses were measured. Next, a new capacitor structure was proposed in order to reduce the electric losses. The transparent conductive film was divided and connected in parallel. The total loss resistance was reduced from 22.4 Ω to 5.30 Ω by using the structure. The transmission efficiencies were measured of 53.7% for the load resistance was 9.74 Ω, 85.9% for 45.9 Ω, and 97.1% for 97.9 Ω.

scholarly journals Comparison of the Efficiency and Load Power in Periodic Wireless Power Transfer Systems with Circular and Square Planar Coils

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4975
Author(s):  
Jacek Maciej Stankiewicz ◽  
Agnieszka Choroszucho
Keyword(s):  
Power Transmission ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Numerical Approach ◽  
Maximum Efficiency ◽  
Power Transfer ◽  
Wireless Power ◽  
Load Power ◽  
Coil Geometry ◽  
Square Planar

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.

Parameter identification of wireless power transfer with a movable receiver

2017 ◽  
Vol 36 (6) ◽  
pp. 1580-1593 ◽  
Author(s):  
Quandi Wang ◽  
Yingcong Wang ◽  
Jianwei Kang ◽  
Wanlu Li
Keyword(s):  
Load Condition ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Power Transfer ◽  
Wireless Power ◽  
Monitoring Method ◽  
Content Type ◽  
Equivalent Impedance ◽  
Input Side ◽  
Parameter Values

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.

scholarly journals Detecting Load Resistance and Mutual Inductance in Series-Parallel Compensated Wireless Power Transfer System Based on Input-Side Measurement

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Longzhao Sun ◽  
Mingui Sun ◽  
Dianguang Ma ◽  
Houjun Tang
Keyword(s):  
Wireless Power Transfer ◽  
Input Voltage ◽  
Load Resistance ◽  
Mutual Inductance ◽  
Input Current ◽  
Power Transfer ◽  
Wireless Power ◽  
Direct Measurements ◽  
Input Side ◽  
In Series

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.

scholarly journals A Method of Estimating Mutual Inductance and Load Resistance Using Harmonic Components in Wireless Power Transfer System

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2728 ◽  
Author(s):  
Dongsheng Yang ◽  
Sokhui Won ◽  
Jiangwei Tian ◽  
Zixin Cheng ◽  
Jongho Kim
Keyword(s):  
Wireless Communication ◽  
Wireless Power Transfer ◽  
Mathematic Model ◽  
Load Resistance ◽  
Mutual Inductance ◽  
Transfer System ◽  
Power Transfer ◽  
Wireless Power ◽  
Wireless Power Transfer System ◽  
Harmonic Components

In general, for the WPT (Wireless Power Transfer) system, as the mutual inductance and load resistance are calculated according to the measured data of both the transmitter and receiver, the wireless communication modules are needed to share data. A method for estimating mutual inductance and load resistance without wireless communication is proposed, based on the fundamental and third harmonic components. The circuit is decomposed with respect to the frequencies, by which the mathematic model is established. The fundamental and harmonic components of the output voltage and current of a high-frequency inverter are found by FFT (Fast Fourier Transform). The experimental WPT system with a SiC power MOSFET is designed, and the effectiveness of the proposed method is verified by the simulation and experiment results. Additional hardware and frequency scanning operation are not needed because of the use of the harmonic components.

Design of magnetic-resonant wireless power transfer links realized with two coils: comparison of solutions

2015 ◽  
Vol 7 (3-4) ◽  
pp. 349-359 ◽  
Author(s):  
Alessandra Costanzo ◽  
Marco Dionigi ◽  
Franco Mastri ◽  
Mauro Mongiardo ◽  
Johannes A. Russer ◽  
...  
Keyword(s):  
Maximum Output Power ◽  
Wireless Power Transfer ◽  
Load Resistance ◽  
Maximum Output ◽  
Power Transfer ◽  
Wireless Power ◽  
Coupled Inductors ◽  
Link Distance ◽  
Novel Approach ◽  
General Network

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.

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
Keyword(s):  
Wireless Power Transfer ◽  
Load Resistance ◽  
Coupling Factor ◽  
Optimization Techniques ◽  
Power Transfer ◽  
Wireless Power ◽  
Or Efficiency ◽  
Series Connection ◽  
Link Distance ◽  
Magnetic Couplings

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.

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