Charging Coil Research Articles

Emergency power supply enabling solar PV integration with battery storage and wireless interface

ABSTRACT This paper presents a detailed investigation of an emergency power supply that enables solar photovoltaic (PV) power integration with a battery energy storage system (BESS) and a wireless interface. Through the utilisation of solar PV-based generation and BESS with wireless/contactless power transmission, the proposed method offers an easy-to-setup and flexible alternative solution for the emergency power supply (EPS) for household appliances and wireless electric vehicle (EV) charging for all weather conditions. During bad weather conditions, the battery acts as the main power supply and can be charged from the solar PV panel and during rainy days, it can be charged from the grid by the proposed wireless interface for emergency use. The proposed system is analysed by mathematical modelling, focusing on the interface of the solar PV, BESS, and load, with inductive power transfer (IPT) as a wireless power transfer (WPT) method. The simulation and a scaled-down experimental prototype are built to demonstrate that the proposed system enables wireless power transfer with PV and BESS, and easy installation can be achieved by just placing the primary charging coil of the proposed power supply close to the wireless charging pad that is available in the existing system for e.g. EV charging. The results show that the load voltage is kept constant at 48 V against the varying input characteristic of the solar panel which is the solar irradiance ranging from 20% to 100% and output characteristics of the load of the proposed integrated system with variation of 20–50%, respectively. Moreover, the wireless power transfer efficiency across the inductive coils is maintained at about 97% under these variations.

Integration of Near Field Communication (NFC) Antenna and Wireless Charging Coil for Portable Electronic Products

Integration of Near Field Communication (NFC) Antenna and Wireless Charging Coil for Portable Electronic Products

Optimization of magnetic coupling structure of electric vehicle wireless charging DD coil

The charging coil plays an important role in the wireless charging system system. However, there are still some problems in the design of the wireless charging coil, such as the low coupling coefficient. In order to improve the coupling effect, this paper proposes an optimized design scheme for the metal shielding layer structure of DD coil. Firstly, the influence of the structure size of DD coil metal plate on the coupling coefficient is studied by the mathematical modeling analysis. Futhermore, the maxwell simulation is used to study the metal plate coupling coefficients with varying structure sizes, addressing receiving uniformity issues. The optimal size of the shielding layer is designed for optimal magnetic coupling in wireless charging. Finally, this paper validates the feasibility of the improved metal shielding layer through experiments. The research in this paper may have a reference role in the wireless charging system of electric vehicles.

Non‐contact and anti‐interference diagnosis of SiC MOSFET module bond wire faults for EV wireless charging device

AbstractSiC MOSFET modules are widely used for bidirectional wireless charging of electric vehicles. However, prolonged use can result in bond wire faults, leading to reliability issues. To address this problem, a non‐contact bond wire monitoring method that can be carried out using the charging coil of the wireless charging device is proposed. Here, two monitoring loops are constructed based on the circuit topology, and their impedance magnitudes are measured on the charging coil to avoid the influence of battery voltage on monitoring results. To detect the bond wire condition, the impedance magnitude difference of the two monitoring loops is chosen as an indicator, which is very sensitive to the bond wire lift‐off. However, the monitoring results may be influenced by the aging of resonant capacitors and the offset of the charging coil. In particular, the influence of the coil offset is significant. To mitigate this effect, a prognostic parameter calibration method is proposed. Experimental results confirm the effectiveness of the proposed method, which provides a promising solution for the reliable and safe operation of SiC MOSFET modules in wireless charging devices.

SPBCSEV: Solar Power Based Charging Station for Electric Vehicles

Electric vehicles, which are in high demand these days, emit no talipipe emissions, significantly reducing smog and greenhouse gas emissions. Electric vehicles use electricity to recharge their batteries rather than fossil fuels such as petrol and diesel. Electric vehicles are more efficient, and when combined with the cost of electricity, charging an electric vehicle is less expensive than filling up with petrol or diesel. With the growing demand for electric vehicles, there is a greater need for dependable and long-term charging infrastructure or systems. The purpose of this paper is to provide a sustainable and convenient charging solution for electric vehicles by utilizing renewable energy sources such as solar power. Furthermore, an electric vehicle charging station is created using an Arduino microcontroller, wireless charging coil modules, a solar panel, and an ESP8266 Wi-Fi module.

An All‐MXene‐Based Flexible, Seamless System with Integrated Wireless Charging Coil, Micro‐Supercapacitor, and Photodetector

AbstractFabrication of miniature‐integrated devices combining energy harvester, energy storage, and various sensors via simple, fast, and efficient ways is strongly desired for the practical application of integrated smart systems. Herein, this work presents a simple one‐step laser scribing method to prepare an all MXene‐based seamlessly integrated system with integrated wireless charging coil, micro‐supercapacitor, and photodetector in a small area of only 1.78 cm2. All the three modules in the integrated system are composed entirely of Ti3C2Tx MXene and are connected with highly conductive MXene wires without additional welding or assembling operation. The energy is first received by the wireless charging coil and then stored in the Zn‐ion micro‐supercapacitor, which is subsequently used to drive the surface‐modified (dodecyl triethoxysilane) DCTES‐MXene‐based photodetector, thus realizing the complete energy cycles. This work conceptually illustrates a simple method for designing and preparing integrated multifunctional wearable devices.

An automated system for cattle reproductive management under the IoT framework. Part I: the e-Synch system and cow responses

The objective of this manuscript was to present the e-Synch system, integrating an intravaginal electronically controlled hormone delivery and sensing device with an IoT platform for remote programming and monitoring. Secondary objectives were to demonstrate system functionality and cow responses to e-Synch. External components of e-Synch include a 3D-printed case with retention wings, a flexible wideband antenna, and silicone membrane for pressure balancing. Internal components include a central control board, battery, wireless charging coil, and two silicone hormone reservoirs connected to individual peristaltic pumps. An accelerometer and a high-accuracy temperature sensor are integrated in the custom printed circuit board (PCB). The IoT platform includes a gateway consisting of Raspberry PI 3 and a CC1352 radiofrequency module that collects sensor data at 915 mHz. Data is transferred to the Google Cloud utilizing the IoT Core service through TCP/IP, and then is pulled by the Pub/Sub service. After routing to a BigQuery table by the Dataflow service, data visualization is provided by Data Studio. Drug delivery protocols are selected using an IOS device app that connects to e-Synch through Bluetooth. Experiments with lactating Holsteins cows were conducted to demonstrate proof-of-concept system functionality and evaluate cow responses. Despite unstable communication and signal discontinuity because of signal strength attenuation by body tissue, devices (n=6) communicated with the IoT platform in 89% (24/27) of use instances. Temperature and accelerometer data were received for at least one 15 min period during an 8 h insertion period from all devices that communicated with the IoT platform. Variation in accelerometer data (± 8.565 m/s2) was consistent with cow activity during experimentation and mean vaginal temperature of 39.1 °C (range 38.6 to 39.5 °C) demonstrated sensor functionality. Hormone release was confirmed in all instances of device use except for one. Cow behavior evaluated through signs of discomfort and pain, and tail raising scores was mostly unaltered by e-Synch. Vaginal integrity and mucus scores also remained unaltered during and after device insertion. In conclusion, the e-Synch device integrated with a controlling app and IoT platform might be used to automate intravaginal hormone delivery and sensing for controlling the estrous cycle of cattle.

Multifunctional Electronic Textiles by Direct 3D Printing of Stretchable Conductive Fibers

AbstractThe integration of functional fibers into wearable devices by traditional methods is commonly completed in weaving. A new post‐weaving method of integrating fiber devices into textiles is needed to address the challenge of incorporating functional fiber into ready‐made garments without tearing down the clothing and re‐weaving. A 3D printing method to simultaneously fabricate and integrate highly stretchable conductive fiber into ready‐made garments with designed patterns is presented. The fabricated sheath–core fiber consists of a styrene–ethylene–butylene–styrene (SEBS) shell and a Ga–In–Sn alloy liquid metal core. The SEBS shell guarantees the high stretchability (up to 600%) and flexibility, while the liquid metal core offers a high conductivity maintained at large deformation. It is shown that sophisticated patterns, which have millimeter‐level‐resolution that are difficult to be integrated into textiles by weaving, and even more laborious to be incorporated into ready‐made garments, can now be easily modified and implemented into both textiles and ready‐made garments by a time‐saving and low‐cost 3D printing method. Utilizing the electrical characteristics of the fiber in pre‐designed patterns, on‐clothing soft electronics can be printed directly. A printed on‐clothing strain sensor, bending sensor, wireless charging coil, and a touch‐sensing network are demonstrated to show the potential applications in wearable electronics.

Fully Implantable Neurostimulation System for Long-Term Behavioral Animal Study.

Spinal cord stimulation (SCS) is an emerging therapeutic option for patients with neuropathic pain due to spinal cord injury (SCI). Numerous studies on pain relief effects with SCS have been conducted and demonstrated promising results while the mechanisms of analgesic effect during SCS remain unclear. However, an experimental system that enables large-scale long-term animal studies is still an unmet need for those mechanistic studies. This study proposed a fully wireless neurostimulation system that can efficiently support a long-term animal study for neuropathic pain relief. The developed system consists of an implantable stimulator, an animal cage with an external charging coil, and a wireless communication interface. The proposed device has the feature of remotely controlling stimulation parameters via radio-frequency (RF) communication and wirelessly charging via magnetic induction in freely moving rats. Users can program stimulation parameters such as pulse width, intensity, and duration through an interface on a computer. The stimulator was packaged with biocompatible epoxy to ensure long-term durability under in vivo conditions. Animal experiments using SCI rats were conducted to demonstrate the functionality of the device, including long-term usability and therapeutic effects. The developed system can be tailored to individual user needs with commercially available components, thus providing a cost-effective solution for large-scale long-term animal studies on neuropathic pain relief.

Pavement integration of an inductive charging system for electric vehicles. Results of the INCIT-EV project

This paper presents first studies carried out in the European project INCIT-EV, to design a solution for integrating a wireless inductive charging system for electric vehicles in a bituminous pavement. In the project, specific tests and simulations were developed to study the mechanical and thermal behaviour of this electric road. In particular, laboratory wheel tracking tests were used to study, at reduced scale, the mechanical behaviour of a charging coil integrated in the pavement. Charging tests were also performed to study the temperature variations produced by the heat dissipation in the inductive coils. Finally, finite element models have been used to simulate the thermal and mechanical response of the system in the pavement structure. The paper presents some main results of this study, which allowed to validate the mechanical behaviour of the proposed pavement structure, but also highlighted risks of overheating when the system is in operation, which will need further investigation.

Thermal Analysis of Coupled Resonant Coils for an Electric Vehicle Wireless Charging System

Electric vehicles use wireless energy transmission to obtain energy, which can effectively avoid the shortcomings of traditional methods. As the carrier of radio energy transmission and reception, the high temperature of the coil triggers the degradation of wireless transmission performance and the aging of the coil, which may cause fire and other safety problems in serious cases. This paper studied the temperature distribution of the magnetically coupled coil model for electric vehicles. Based on the study of the basic law of heat transfer, the coil model was established using ANSYS software, and the boundary conditions and relevant parameters were set. After many simulation experiments and comparisons, it was finally determined that the transmitting coil and the receiving coil were the same sizes, the inner diameter of the coil was 100 mm, the outer diameter of the coil was 181 mm, and the coupling distance between the transmitting coil and the receiving coil was set to 60 mm. Coil models were simulated and analyzed using different materials. The simulation results show that after 30 min of system operation, the material chosen from the temperature range may have been gold, silver, copper, or aluminum, but from the comprehensive consideration of cost and performance, the material of the coil in the model was finally set to copper. Copper was the best material; its temperature maximum was 74.952 °C and lower than the safety value of 80 °C. It is hoped that this study will provide a reference for wireless charging coil design.

Implantable Cardioverter-defibrillator Magnetic Interference by the iPhone 12: Is It Clinically Significant?

The iPhone 12 series (Apple, Inc., Cupertino, CA, USA) contains a circular array of magnets around a central charging coil (compatible with “Magsafe” technology). The device was recently reported to have magnetic interference with implantable cardioverter-defibrillators (ICDs). We sought to test the electromagnetic interference of the iPhone 12 in inhibiting life-saving therapies of ICDs in clinical settings. After obtaining written informed consent, an iPhone 12 was placed over the device generators of 17 patients in the ICD clinic. Device interrogation was performed immediately before and after placing the iPhone over the ICD generator to evaluate for any inhibition of device therapies. To emulate a real-world scenario, the iPhone 12 was not placed directly over the skin above the device generator but instead was positioned over the patients’ clothes. None of the device interrogations revealed interruption of device therapies due to the iPhone. We concluded that, despite the iPhone having shown in vitro interference of ICD functioning, its effects are not clinically relevant in vivo. Larger studies need to be performed to confirm this finding and guide safety recommendations regarding the use of iPhones containing magnets by patients with implanted ICDs.

Molecular Modeling and Simulation Analysis of Antimicrobial Photodynamic Therapy Potential for Control of COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can enter the host cells by binding the viral surface spike glycoprotein (SG) to angiotensin-converting enzyme 2. Since antiviral photodynamic therapy (aPDT) has been described as a new method for inhibiting viral infections, it is important to evaluate whether it can be used as a photoactivated disinfectant to control COVID-19. In this in silico study, SARS-CoV-2-SG was selected as a novel target for curcumin as a photosensitizer during aPDT to exploit its physicochemical properties, molecular modeling, hierarchical nature of protein structure, and functional analysis using several bioinformatics tools and biological databases. The results of a detailed computational investigation revealed that SARS-CoV-2-SG is most similar to 6VXX_A, with 100% query cover and identity. The predicted structure of SARS-CoV-2-SG displayed that it is a protein with a positive charge and random coil dominates other secondary structures located outside the viral cell. The protein-protein interaction network showed that SARS-CoV-2-SG interacted with ten potential interacting partners. In addition, primary screening of binding modes through molecular docking showed that curcumin desires to bind and interact with residues of SARS-CoV-2-SG as the main site to enhance the yield of aPDT. Overall, the computer simulation reveals that SARS-CoV-2-SG can be a suitable target site for interaction with curcumin during aPDT.

Design of Wireless Charging Coils for Aero-engine Telemetry Information Transmission System

Abstract In order to meet the need of non-contact transmission of aero-engine telemetry information, first of all, a rotor disk and a stator disk suitable for near field communication are designed in this paper, then, the coil design of wireless charging system suitable for high centrifugal force load is carried out. The designed single charging coil can charge two receiving coils at the same time. In order to eliminate the influence of aluminum alloy rotor disk and stator disk on charging performance, concave ferrite slots are installed on rotor disk and stator disk respectively to shield charging coil and receiving coil. The designed charging coils are fabricated and integrated with rotor disk and stator disk respectively. Finally, the designed charging coil and receiving coils are connected into the charging system for testing. The test results show that the charging coil and receiving coils are completely matched with the charging circuit and receiving circuit, and their performance can fully meet the use requirements of aeroengine telemetry information transmission system.

Design and Performance Analysis of Misalignment Tolerant Charging Coils for Wireless Electric Vehicle Charging Systems

In order to design a high efficiency Wireless Electric Vehicle Charging (WEVC) system, the design of the different system components needs to be optimized, particularly the design of a high-coupling, misalignment-tolerant inductive link (IL), comprising primary and secondary charging coils. Different coil geometries can be utilized for the primary and the secondary sides, each with a set of advantages and drawbacks in terms of weight, cost, coupling at perfect alignment and coupling at lateral misalignments. In this work, a Finite Element Method (FEM)-based systematic approach for the design of double-D (DD) charging coils is presented in detail. In particular, this paper studies the effect of different coil parameters, namely the number of turns and the turn-to-turn spacing, on the coupling performance of the IL at perfect alignment and at ±200 mm lateral misalignment, given a set of space constraints. The proposed design is verified by an experimental prototype to validate the accuracy of the FEM model and the simulation results. Accordingly, FEM simulations are utilized to compare the performance of rectangular, DD and DDQ coils. The FEM results prove the importance of utilizing an additional quadrature coil on the secondary side, despite the added weight and cost, to further improve the misalignment tolerance of the proposed inductive link design.

Automated Fiber Embedding for Soft Mechatronic Components

Many recent advances in smart composites for soft robotics have resulted from integration of long fibers to precisely control structural and functional properties. Compared to the time-consuming, laborious and error-prone process of manual long fiber placement typically used, Automated Fiber Embedding (AFE) has an enormous potential in soft robotics due to its repeatability, precision, and ease of integration with commonly used elastomers. In this work, three different approaches for automated layering and embedding of fibers inside silicone elastomers are presented. These techniques enable fabrication of soft composites comprising linear and free-form long fiber patterns without user intervention or manual post processing. To demonstrate the versatility of the techniques, several soft robotic applications ranging from actuators to inductive charging coils are presented.

AC Loss Reduction Through Flux Diverters for Superconducting Wireless Charging Coils at High Frequencies

Wireless power transfer (WPT) for electric vehicles (EVs), also known as wireless charging, is a fast-developing technology with many advantages over conventional cable charging. Novel materials such as high temperature superconductors (HTS) can be used to increase system performance. However, HTS coils have high ac losses at wireless charging frequencies (10-100 kHz) and this is crucial for WPT systems. Flux diverters have been used in the past for dc and low frequency (~50 Hz) superconducting applications but their effectiveness at high frequencies is unexplored. This article investigates the impact of flux diverters on HTS double pancake coils operating at high frequencies up to 85 kHz, commonly used for wireless charging of EVs. Various geometric characteristics of flux diverters are investigated such as air gap between diverter and coil, thickness, and width. A 2-D axisymmetric multilayer model using finite element analysis was used to examine the coil and diverter losses at such frequencies and different load factors (LFs) between 0.1 and 0.8. It is demonstrated that flux diverters are a viable option to reduce the coil losses even at high frequencies and the width of the flux diverter has the biggest impact on the loss reduction. In general, flux diverters are more suitable for applications using high LFs. Lastly, the impact of the diverter in terms of magnetic field distribution above the coil and overall loss distribution in the HTS coil was examined.

Accurate Offset Angle Detection Strategy for Wireless Charging Coils Based on Electronic Compasses

In order to achieve high-efficiency transmission in the electric vehicles’ wireless power transfer system, it is important to ensure that the transmitting and receiving coils are properly aligned. Only if the real-time offset position of the two coils is obtained can the driver align the two coils. This paper proposes a novel offset angle detection strategy for wireless charging coils based on electronic compasses, aiming at the angle offset between transmitting and receiving coils. An electronic compass is placed in the transmitting coil and the receiving coil, respectively. In this process, the exact angle positioning of the charging coil is realized with the aid of geomagnetic and the application of vector theory to determine the offset angle between the two coils. Finally, an experimental prototype has been constructed. The experimental results indicate that the positioning error of the coil angle is within 1 °. This method’s measurement process is simple, and the deviation angle between the coils can be directly and conveniently calculated by examining the electronic compass output, which helps guide to align the transmitting coil with the receiving coil.

RESEARCH ON SHIELDING AND ELECTROMAGNETIC EXPOSURE SAFETY OF AN ELECTRIC VEHICLE WIRELESS CHARGING COIL

RESEARCH ON SHIELDING AND ELECTROMAGNETIC EXPOSURE SAFETY OF AN ELECTRIC VEHICLE WIRELESS CHARGING COIL

Optimal Number of Turns Design of the IPT Coils for Laptop Wireless Charging

The coil design of the inductive power transfer (IPT) for a transmitter (Tx) and receiver (Rx) is crucial to determine the performance of the IPT. Considering core loss and copper loss of the Tx and Rx coils, which are major loss terms of the whole IPT system, determination of the winding turns for the Tx and Rx coils becomes a key factor for maximum power transfer design of the IPT coils. In this paper, an optimal turns design of IPT coils for laptop wireless charging applications with a maximum power transfer efficiency is proposed. Under a specific design requirement of IPT, optimal turns of the Tx and Rx coils N1,op and N2,op can be determined by the proposed IPT coil design procedure with a finite-element-method (FEM) based simulation analysis. From the results of the coil design by the proposed IPT coil design methodology, N1,op and N2,op for maximum power efficiency, and input DC voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> for the target load power can be found by the proposed coil design procedure. The 40W prototypes of the two symmetry and asymmetry IPT coils for laptop wireless charging were fabricated, and verified by simulation and experiments. To separately verify the core and copper loss of the IPT coils, a resistance model and Steinmetz equation-based methods were comparatively evaluated, and it was found that they matched well at a core temperature condition of below 40oC. The results showed that the total weight and the thickness of the Tx and Rx coils as well as the maximum power efficiencies of 95.1% and 96.8% for the symmetry and asymmetry cases were obtained by the proposed IPT coil design procedure, which becomes a practical solution for the laptop wireless charging coil design.