receiver coil
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Author(s):  
Jun Xu ◽  
Eugeni L. Doubrovski ◽  
Jo Geraedts ◽  
Yu Song

Abstract The geometric shapes and the relative position of coils influence the performance of a three-dimensional (3D) inductive power transfer system. In this paper, we propose a coil design method for specifying the positions and the shapes of a pair of coils to transmit the desired power in 3D. Given region of interests (ROIs) for designing the transmitter and the receiver coils on two surfaces, the transmitter coil is generated around the center of its ROI first. The center of the receiver coil is estimated as a random seed position in the corresponding 3D surface. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the set of coils. In each step, the shape of the extension, i.e. a new turn of the receiver coil, is found as a spiral curve based on the convex hulls of adjacent turns in the 2D projection plane along their normal direction. Then, the optimal position of the receiver coil is found by maximizing the efficiency of the system. In the next step, the position and the shape of the transmitter coil are optimized based on the fixed receiver coil using the same method. This zig-zag optimization process iterates until an optimum is reached. Simulations and experiments with digitally fabricated prototypes were conducted and the effectiveness of the proposed 3D coil design method was verified. Possible future research directions are highlighted well.


Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2928
Author(s):  
Joungha Lee ◽  
Seung Beop Lee

Most of the coil designs for wireless power transfer (WPT) systems have been developed based on the “single transmitter to a single receiver (S-S)” WPT systems by the empirical design approaches, partial domain searches, and shape optimization methods. Recently, the layout optimizations of the receiver coil for S-S WPT systems have been developed using gradient-based optimization, fixed-grid (FG) representation, and smooth boundary (SB) representation. In this paper, the new design optimization of the transmitter module for the “single transmitter to multiple receivers (S-M)” WPT system with the resonance optimization for the S-M WPT system is proposed to extremize the total power transfer efficiency while satisfying the load voltage (i.e., rated power) required by each receiver and the total mass used for the transmitter coil. The proposed method was applied to an application model (e.g., S-M WPT systems with two receiver modules). Using the sensitivity of design variables with respect to the objective function (i.e., total power transfer efficiency) and constraint functions (i.e., load voltage of each receiver module and transmitter coil mass) at each iteration of the optimization process, the proposed method determines the optimal transmitter module that can maximize the total power transfer efficiency while several constraints are satisfied. Finally, the optimized transmitter module for the S-M WPT system was demonstrated through comparison with experiments under the same conditions as the simulation environment.


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

2021 ◽  
Vol 2071 (1) ◽  
pp. 012027
Author(s):  
S F Abdul Halim ◽  
M H Zakaria ◽  
Z Zakaria ◽  
A N Norali ◽  
A Mohd Noor ◽  
...  

Abstract Monitoring of fetal condition during labor could save hundred lives in a single year. During labor, fetus is at critical condition as acidosis may occur suddenly without any early symptoms. Invasive method such as Fetal Blood Sampling (FBS) has been used to detect the decline in pH level of fetus. However, fetal loss rate after FBS may range from 1.4% up to 25%. In this paper, magnetic field induction spectroscopy was implemented to determine fetal acidosis by using primary magnetic field cancellation technique. Magnetic Induction Spectroscopy (MIS) probe was design where transmitter coil (TX) is perpendicular to receiver coil (RX). The result shows that the secondary magnetic field produced have been successfully measured without any interruption from primary magnetic field. By using transmitter input 1A, it shows that voltage is inversely proportional to the blood pH due to the conductivity properties of blood.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6144
Author(s):  
Bohdan Pakhaliuk ◽  
Viktor Shevchenko ◽  
Jan Mućko ◽  
Oleksandr Husev ◽  
Mykola Lukianov ◽  
...  

This study proposed an approach to dynamic wireless charging that uses a rotating receiver coil. Our simulation study focused on the verification of a novel way of increasing the coupling coefficient and power transfer stability by following the flux of the transmitting coils. To obtain the highest possible coupling by means of the FEM analysis, we studied the optimization of the trajectory of the angular velocity of the rotating receiver. The coupling coefficient trajectories that were obtained were simulated by means of the state space model with three transmitters. Our comprehensive analysis showed that the proposed approach of wireless power transmission enabled a 40% increase in the usage of track space.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kiyokadzu Ebata ◽  
Sakon Noriki ◽  
Kunihiro Inai ◽  
Hirohiko Kimura

Abstract Background Postmortem magnetic resonance imaging (MRI) has been used to investigate the cause of death, but due to time constraints, it is not widely applied to the heart. Therefore, MRI analysis of the heart after formalin fixation was previously performed. However, the changes in MRI signal values based on the fixation time of formalin were not investigated. The objective was to investigate changes over time in the T1- and T2-values of MRI signals in normal areas of hearts removed during autopsy, hearts subsequently fixed in formalin, and heart specimens sliced for the preparation of pathological specimens. Methods The study subjects were 21 autopsy cases in our hospital between May 26, 2019 and February 16, 2020 whose hearts were removed and scanned by MRI. The male:female ratio was 14:7, and their ages at death ranged from 9 to 92 years (mean age 65.0 ± 19.7 years). Postmortem (PM)-MRI was conducted with a 0.3-Tesla (0.3-T) scanner containing a permanent magnet. A 4-channel QD head coil was used as the receiver coil. Scans were performed immediately after removal, post-formalin fixation, and after slicing; 7 cases were scanned at all three time points. Results The T1- and T2-values were calculated from the MRI signals of each sample organ at each scanning stage. Specimens were sliced from removed organs after formalin fixation, and the changes in T1- and T2-values over time were graphed to obtain an approximate curve. The median T1-values at each measurement time point tended to decrease from immediately after removal. The T2-values showed the same tendency to decrease, but this tendency was more pronounced for the T1-values. Conclusion MRI signal changes in images of heart specimens were investigated. Formalin fixation shortened both T1- and T2-values over time, and approximation formulae were derived to show these decreases over time. The shortening of T1- and T2-values can be understood as commensurate with the reduction in the water content (water molecules) of the formalin-fixed heart.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5754
Author(s):  
Zhengwang He ◽  
Zhiyong Li ◽  
Ruoyue Wang ◽  
Ying Fan ◽  
Minqian Xu

This paper presents the design and optimization of a wireless power transfer (WPT) charging system based on magnetically coupled resonant technology, applied to an Unmanned Aerial Vehicle (UAV). In this paper, a charging system, including dual active transmitter coils and a single receiver coil, is proposed. The dual transmitting coils adopt a coaxial structure with different radii. This structure simplifies the calculation of the complex mutual inductance between the coils to a function of mutual inductance only related to the value of the radial misalignment. Aiming toward a constant charging power, the optimal transmission efficiency of electric energy is achieved by controlling the input voltages of the active coils, which are solved via a set of equations defined as Lagrange multipliers. The simulation results of the 570 V and 85,000 Hz system verified the validity of the proposed wireless UAV charging scheme.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5436
Author(s):  
Krithikaa Mohanarangam ◽  
Yellappa Palagani ◽  
Kun-Hee Cho ◽  
Jun-Rim Choi

Inductive power links are most viable for the long-term powering of cardiac pacemakers. Designing an inductive power link without surpassing the specific absorption rate (SAR) for modern leadless cardiac pacemakers (LCPs) remains a challenging task because of its size and implantation depth. The inductive power link employed in the conventional works is either designed at a high frequency or based on the size, shape, weight, and implantation depth of conventional cardiac pacemakers. Here, a 3-coil inductive power transfer link with a circular transmitter coil and solenoidal receiver coil is designed at 13.56 MHz to provide uninterrupted power to the modern LCPs. Considering the food and drug administration approved term for implant size of modern LCP, the receiver coil is designed with 6 mm diameter and 6.5 mm length. The performance of the link has been verified through simulations and measurements under perfect alignment, lateral and/or angular misalignments, and distance variation between the coils. At a 50 mm horizontal distance between transmitter and receiver coils, the transmission coefficient is −30.9 dB. The maximum simulated average SAR at heterogeneous phantom is 0.30 W/kg, which is lower than the limit set by the Federal Communications Commission for radiation threshold exposure. Experiments conducted on pork’s heart verified the reliability of the simulated results. At a 50 mm distance between the coils, the measured transmission coefficient is −34 dB, and at an input power of 1 W, the power delivered to the load is 0.7 mW.


2021 ◽  
Vol 11 (16) ◽  
pp. 7707
Author(s):  
Neetu Ramsaroop ◽  
Oludayo O. Olugbara

This research paper presents the design of a wireless power transfer (WPT) circuit integrated with magnetic resonance coupling (MRC) and harvested radio frequency (RF) energy to wirelessly charge the battery of a mobile device. A capacitor (100 µF, 16 V) in the RF energy harvesting circuit stored the converted power, and the accumulated voltage stored in the capacitor was 9.46 V. The foundation of the proposed WPT prototype circuit included two coils (28 AWG)—a transmitter coil, and a receiver coil. The transmitter coil was energized by the alternating current (AC), which produced a magnetic field, which in turn induced a current in the receiver coil. The harvested RF energy (9.46 V) was converted into AC, which energized the transmitter coil and generated a magnetic field. The electronics in the receiver coil then converted the AC into direct current (DC), which became usable power to charge the battery of a mobile device. The experimental setup based on mathematical modeling and simulation displayed successful charging capabilities of MRC, with the alternate power source being the harvested RF energy. Mathematical formulae were applied to calculate the amount of power generated from the prototype circuit. LTSpice simulation software was applied to demonstrate the behavior of the different components in the circuit layout for effective WPT transfer.


2021 ◽  
Author(s):  
Jun Xu ◽  
E. (Zjenja) L. Doubrovski ◽  
Jo M. P. Geraedts ◽  
Yu (Wolf) Song

Abstract The geometric shapes of coils influence the performance of a 3D IPT system. In this paper, we proposed a 3D coil design method based on (3D) printing electronics. Given a 3D transmitter coil, the center position of the receiver coil is estimated as a random seed position in the corresponding 3D surface first. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the coil. For each extension of the coil, i.e. a new turn, the shape of the coil is optimized by calculating the convex hull of the new turn in the 2D projection plane. Using this method, we are able to generate a receiver coil to transmit “just enough” power at a given seed position. Then, by fixing the receiver coil, the 3D shape of the transmitter coil can be optimized as well. This zig-zag optimization process iterates until there are few changes of the position and 3D shapes in the iteration. Experiment results with Ansys Maxwell verified the effectiveness of the proposed 3D coil design method, and highlighted possible future research directions as well.


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