Wireless Power Transfer Coils Research Articles

USING ARTIFICIAL NEURAL NETWORKS TO IMPROVE THE EFFICIENCY OF TRANSFORMERS USED IN WIRELESS POWER TRANSMISSION SYSTEMS FOR DIFFERENT COIL POSITIONS

This study uses magnetic resonance-based coupling theory to study the various placements of transmitter and receiver coils in wireless power transfer (WPT) systems. Various coil placements are examined to show where high efficiency can be achieved within the air gap. Basic characteristics such as self-inductance, mutual inductance, and coupling coefficient were calculated. Artificial neural networks (ANNs) in WPT are a powerful technique for predicting performance characteristics. Using ANNs provides an excellent method for streamlining the design process and reducing time-consuming calculations. To quickly determine and optimize coil design, this study compares recent research on ANN applications in WPT and the performance of different types of ANNs in WPT systems. An artificial neural network (ANN) was trained to predict the magnetic properties of a wireless power transfer (WPT) device. Appropriate cost functions have been implemented to train the ANN properly. It was shown that the trained ANN can effectively reproduce the data obtained by the finite element method (FEM). The results show an effective power transmission at different coil placements, with decreased efficiency observed after a certain distance. These data will help determine the proposed WPT system's air gap and angular limits.

Analysis of an Oscillatory System With Three Coupled Coils for Wireless Power Transfer

Analysis of an Oscillatory System With Three Coupled Coils for Wireless Power Transfer

Evaluation of Additive Manufacturing for Wireless Power Transfer Applications

Additive Manufacturing (AM) has emerged as an economical and feasible technology for creating industrial components. This paper evaluates the use of AM for inductive Wireless Power Transfer (WPT) systems. In particular, the innovative use of metal 3D printing is proposed as a manufacturing process for the coils. For this reason, the recent improvement of metal AM is proposed as a suitable solution to increase design opportunities, reduce costs and production time while improving transmission efficiency. In fact, the WPT coil current distribution can be preliminarily studied through Finite Element Analysis (FEA) to optimize its cross-section and geometry. In this work, a general design procedure for WPT coils using metal AM is presented and this technology is compared with traditional solutions (i.e. hollow and litz wire) through extensive experimental measurements. The analysis shows that AM allows to reduce the parasitic resistance, costs and weight while increasing the transmission efficiency. Thus, the obtained results confirm the potential of AM for producing WPT coils, nominating this technology as a flexible, sustainable, and rapid solution for custom WPT coils production.

Hybrid electromagnetic Halbach array for wireless power transfer (WPT) system using variable and uniform pitch coils

AbstractThe electromagnetic Halbach array (EHA) for wireless power transfer (WPT), designed to improve the transferred power and power transfer distance, has been proven to be effective and can be applied in various consumer applications. This paper presents a hybrid form of the EHA, aimed at improving the quality of power generated and transmitted. The expression for the determination of the magnetic field of a variable pitch flat coil for wireless power transfer and other uses has been derived. The average magnetic field, magnetic flux, and power transfer efficiency are investigated. The power transfer efficiency and the average magnetic field generated by four different design considerations were compared. The hybrid electromagnetic Halbach array wireless power transfer system (HEHA‐WPTS) has also been studied and results are compared with the conventional arrangements. Simulations and experiments were carried out to verify the analytical results obtained. According to the results obtained, the HEHA‐WPTS, with a base coil with variable pitches and uniform side coils, produces a more uniform average magnetic field and a better average power transfer efficiency over a longer power transfer distance.

Anti-Offset Multicoil Underwater Wireless Power Transfer Based on a BP Neural Network

Autonomous underwater vehicles (AUVs) are now widely used in both civilian and military applications; however, wireless charging underwater often faces difficulties such as disturbances from ocean currents and errors in device positioning, making proper alignment of the charging devices challenging. Misalignment between the primary and secondary coils can significantly impact the efficiency and power of the wireless charging system energy transfer. To address the issue of misalignment in wireless charging systems, this paper proposes a multiple transfer coil wireless power transfer (MTCWPT) system based on backpropagation (BP) neural network control combined with nonsingular terminal sliding mode control (NTSMC) to enhance further the system robustness and efficiency. To achieve WPT in the ocean, a coil shielding case structure was equipped. In displacement experiments, the proposed multi-transmitting coil system could achieve stable power transfer of 40 W and efficiency of over 78.5% within a displacement range of 8 cm. The system robustness was also validated. This paper presents a new AUV energy supply solution based on MTCWPT. The proposed MTCWPT system can significantly improve the navigation performance of AUVs.

Optimal design of wireless power transfer coils for biomedical implants using machine learning and meta-heuristic algorithms

Optimal design of wireless power transfer coils for biomedical implants using machine learning and meta-heuristic algorithms

Optimization of a Circular Planar Spiral Wireless Power Transfer Coil Using a Genetic Algorithm

Optimization of a Circular Planar Spiral Wireless Power Transfer Coil Using a Genetic Algorithm

Design and Parameter Optimization of Double-Mosquito Combination Coils for Enhanced Anti-Misalignment Capability in Inductive Wireless Power Transfer Systems

This paper proposes a novel double-mosquito combination (DMC) coil for inductive wireless power transfer (IPT) systems to improve their anti-misalignment capability. The DMC coil consists of a mosquito coil with single-turn spacing and a tightly wound close-wound coil. By superimposing the magnetic fields generated by both coils, a relatively uniform magnetic field distribution is achieved on the receiving coil plane. This approach addresses the challenges of significant output voltage fluctuations and reduced transmission efficiencies caused by coupling coil misalignments in conventional IPT systems. To further optimize the DMC coil, an interaction law between its parameters and the mutual inductance is established, setting the coil mutual inductance fluctuation rate as the optimization objective, and using the coil turn spacing, number of turns, and outer diameter as constraint conditions. The beetle antennae search algorithm (BAS) is employed to enhance the whale optimization algorithm (WOA), facilitating the adaptive optimization of the coil parameters. An experimental IPT system platform with a 50 mm transmission distance is developed to validate the robust anti-misalignment capability of the proposed coil. The results demonstrate that within a horizontal misalignment range of 50 mm, the system’s output voltage fluctuation rate stays below 7.4%, and the transmission efficiency remains above 83%.

Improved Design of PCB Coil for Magnetically Coupled Wireless Power Transfer

In recent years, wireless power transfer (WPT) has progressed rapidly in both theory and commercialization. However, existing research into WPT coil design for low-power devices to mitigate the coil offset is limited. A dual-layer printed circuit board (PCB) structure is proposed in this paper to mitigate the coil offset while retaining manufacturing simplicity for practical uses. Specifically, the impacts of key geometric parameters on the coil quality factor and coupling coefficient are analyzed through models and simulations. Equivalent PCB coils were formed for mutual inductance models, and four basic compensation circuits were analyzed. The impacts of changes in coil thickness, line width, turn spacing, and number of turns on the quality factor of PCB coils were analyzed with a fixed outer diameter of the coil. Eleven types of PCB coils were manufactured to verify the simulation results. The offset transmission efficiency can reach 46.6% with an output power of 14.4 W. The PCB coil with improved design could offer remarkable improvements in the WPT system for low-power electronic devices.

Implementation of the irregular pulse density modulation‐controlled wireless power transfer system for constant current and constant voltage output

SummaryIn this paper, irregular 32 pulse density modulation (PDM)‐controlled wireless power transfer (WPT) system is proposed for constant current (CC) and constant voltage (CV) outputs. The proposed WPT system has a load independent ZPA frequency characteristic with CC and CV outputs. Thus, soft switching conditions are achieved for both CC and CV outputs. An experimental prototype was prepared to validate the effectiveness of the proposed irregular 32 PDM‐controlled WPT system. WPT coil design parameters are presented and analyzed with lateral and rotational misalignment conditions in ANSYS. The experiments were determined as 3 A for CC output and 200 V for CV output. The maximum efficiency of the proposed system is measured (95.34%) at aligned coils with 100 mm air gap. In addition, the efficiency results are presented and evaluated by performing experimental studies under both lateral and rotational misalignment conditions.

Varied-Frequency CC–CV Inductive Wireless Power Transfer with Efficiency-Regulated EV Charging for an Electric Golf Cart

Wireless electric vehicle (EV) charging is an important operation for valuable EV options in modern life. Inductive wireless EV charging needs constant current and voltage (CC–CV) charge controllers. This paper presents 750 W variable frequency CC–CV inductive wireless charging for an e-golf cart 50 Ah 72 V Li-ion battery. Due to this system’s low power, the system’s efficiency may be weak; the secondary-side (SS) maximum efficiency-controlled (MEC) converter was validated. The golf cart’s battery characteristics were evaluated to design and experiment with inductive wireless power transfer (IPT) coils and an integration system for a 42 kHz resonant frequency. The CC–CV charged control is an infrastructural part of the H-bridge inverter at varied frequencies from 50 kHz to 56 kHz when the DC input voltage is 310 V, and in the range of 44 kHz to 46 kHz at the 155 V input. The results found the charging of 9 A CC, 82 V CV and 730 W. The 310 V input voltage system without the SS MEC converter’s efficiencies was 62% to 72% and it was improved to 65% to 81% using the SS MEC converter. Finally, the best cases were validated at the 155 V DC input voltage and the system with the SS MEC converter had 76% to 86% efficiency.

Propulsion and Control of Microrobot Using a Multi-Selective Wireless Power Transfer Coil

Microrobots have been actively studied in recent years due to their mobility and usability. It is important to receive electrical energy from outside through wireless power transfer system because active circuits such as sensors and microrod controller unit should be included and operating time should be sufficient to increase the usability of microrobot. In this research, we propose a multi-selective wireless power transfer coil and structure to maximize the usability of the microrobot that can receive electrical energy with wireless power transmission systems and can be propelled and rotated at the same time. The proposed multi-selective wireless power transfer coil system architecture is described with a theoretical explanation of the magnetic force acting on the microrobot. To verify the proposed model, it has been verified through simulation and experimental verification that the time-varying magnetic field generated from four transmitting coils is suitable for the propulsion, generating torque, and power transmission of microrobot. To validate the proposed system, a 3 mm-sized microrobot is used for experimentation. The experimental results show that the microrobot is able to freely move and rotated as intended by controlling the external incident magnetic field.

A Double-Transmitting Coil Wireless Power Transfer System Based on Parity Time Symmetry Principle

A Double-Transmitting Coil Wireless Power Transfer System Based on Parity Time Symmetry Principle

Single-Phase Wireless Electric Vehicle Charger Using EF2 Inverter

This paper proposes a wireless battery charger topology for electric vehicle (EV) application that can be installed in public charging infrastructure as well as in home premises. The proposed topology can maintain constant current as well as constant voltage at the battery terminal and simultaneously can maintain near unity power factor at the input side using power factor correction (PFC) operation and thus satisfy all the criteria of a standard EV charger. The heart of the wireless power transfer (WPT) scheme is a high-frequency (HF) inverter. In this work, a class EF2 inverter is used to generate HF AC in such a way that it can deliver power with variable loading condition while maintaining constant current (CC) or constant voltage (CV) according to the requirement of CC-CV charging profile. To supply power to this EF2 inverter, an AC-DC front-end converter (stage-1) is integrated with the charger. The stage-1 is operated as a constant voltage source to the EF2 inverter for CC mode and constant current source for CV mode operation. CC-CV at the battery end and PFC at the input end are achieved only by controlling the gate pulse of stage-1. The WPT coils are first simulated using Ansys Maxwell package, and the complete charger is simulated with PSIM simulation software. A scaled-down 200 W laboratory prototype of the proposed charger is developed and tested with a resistive load to validate the idea. The wireless power transfer is achieved for a maximum distance of 12 cm between the transmitting and receiving coil. Finally, the charger is tested to charge both 12 V and 24 V battery packs and the CC-CV charging profile is presented for the 24 V, 30 Ah battery pack.

Design and Optimization of Planar Spiral Coils for Powering Implantable Neural Recording Microsystem.

This paper presents a design and optimization method utilizing inductive coupling coils for wireless power transfer in implantable neural recording microsystems, aiming at maximizing power transfer efficiency, which is essential for reducing externally transmitted power and ensuring biological tissue safety. The modeling of inductive coupling is simplified by combining semi-empirical formulations with theoretical models. By introducing the optimal resonant load transformation, the coil optimization is decoupled from an actual load impedance. The complete design optimization process of the coil parameters is given, which takes the maximum theoretical power transfer efficiency as the objective function. When the actual load changes, only the load transformation network needs to be updated instead of rerunning the entire optimization process. Planar spiral coils are designed to power neural recording implants given the challenges of limited implantable space, stringent low-profile restrictions, high-power transmission requirements and biocompatibility. The modeling calculation, electromagnetic simulation and measurement results are compared. The operating frequency of the designed inductive coupling is 13.56 MHz, the outer diameter of the implanted coil is 10 mm and the working distance between the external coil and the implanted coil is 10 mm. The measured power transfer efficiency is 70%, which is close to the maximum theoretical transfer efficiency of 71.9%, confirming the effectiveness of this method.

AC loss mitigation for high temperature superconducting coils in wireless power transfer

AC loss mitigation for high temperature superconducting coils in wireless power transfer

Reducing unwanted emissions of a wireless power transfer coil by using a parasitic loop element

Reducing unwanted emissions of a wireless power transfer coil by using a parasitic loop element

Optimal Design of Transmission Characteristics for Hexagonal Coil Wireless Power Transfer System Based on Genetic Algorithm

Effective optimization methods are used to guide the optimal design of coil parameters, which is significant for improving the transmission performance of the wireless power transfer (WPT) system. Traditional methods mostly rely on the exhaustive attack method and finite element analysis (FEA) to achieve the coil parameter design, which have the disadvantages of complex modeling and time-consumption. To overcome these limitations, this study proposes an optimization strategy based on the genetic algorithm (GA), which considers the actual requirements of the efficiency and power of the WPT system. First, a direct integration method is proposed to simplify the analytical solution process of the mutual inductance between the hexagonal coils. Based on the mutual inductance model, the transmission characteristics of the hexagonal coil WPT system are deeply analyzed by the control variable method. Most importantly, with the proposed optimization objective function and its constraints, the GA is used to automatically achieve multi-parameter optimization of the hexagonal coil. Finally, a 500 W WPT system experimental platform is established, and the experimental results verify the feasibility of the proposed optimization method.

A novel method for calculating the mutual inductance between two perpendicular coils in wireless power transfer

SummaryThe perpendicular coil is increasingly applied in some wireless power transfer (WPT) systems where space position is limited. The existing method of calculating the mutual inductance between perpendicular coils is mainly applied to rectangular and circular coils. However, the practical rectangular coil often has rounded corners, so it unavoidably introduces systematic errors. Concerning this issue, this paper proposed an analytical method to calculate the mutual inductance between mutually perpendicular round‐corner rectangular (RCR) coils. The proposed method is based on a second‐order vector potential (SOVP) model where the mutual inductance between the coils is described as a double integral formula. In this formula, a novel shape and position function is introduced. This shape and position function describes not only RCR coils but also rectangular (including square), circular, and runway ones. A series of experiments were used to validate the proposed method. According to the consistency validation, the proposed method can be more generalized for calculating the mutual inductance of rectangular and circular coils. Through experimental comparison, the proposed method computes the mutual inductance between the perpendicular coil in excellent agreement with the measured ones. Therefore, the proposed method unifies the mutual inductance calculation of mutually perpendicular circular, rectangular (square), runway, and RCR coils and can provide an important basis for designing WPT systems using the above coils.

Solar Wireless Charging For Electric Vehicle While Driving

This paper presents a novel concept of solar wireless charging for electric vehicles (EVs) while driving. The idea is to integrate solar panels into the roads and use wireless charging technology to transfer energy from the solar panels to the EVs. . To overcome these challenges, several approaches have been proposed, including increasing battery capacity, improving charging infrastructure, and using alternative energy sources. One promising approach is to use solar energy to charge EVs while driving. Solar energy is abundant and renewable, and it can be harnessed using solar panels installed on the roads. However, traditional charging methods, such as plug-in charging, have limitations in terms of convenience and efficiency. Wireless charging technology, on the other hand, has the potential to overcome these limitations by enabling charging while driving without the need for physical connections. we propose a novel concept of solar wireless charging for EVs while driving. The proposed system integrates solar panels into the roads and uses wireless charging technology to transfer energy from the solar panels to the Evs. Key words: Electric road system, wireless power transfer, transmitter and receiver coils, power lanes, e-vechile ,charging while driving, no battery drain, easy to use, get charge while running , future oriented.