Wireless Power Transfer Coils Research Articles

A foreign object detection method based on a laminated coil for wireless power transfer

Foreign objects in magnetically coupled resonant wireless power transfer (MCR-WPT) systems cause eddy effects, reducing efficiency and raising the temperature. To address this, a high-frequency multilayer detection coil and composite topology circuit are designed to enhance sensitivity by dynamically adjusting component parameters. Verified through Maxwell simulation, the proposed method improves detection efficiency by 46% and eliminates blind spots compared to square coils. The detection range expands by 66% with a 3 × 3 reverse series-laminated coil, effectively decoupling sub-coils and broadening coverage. Experimental results show accurate detection of various foreign objects, such as iron and copper, by analyzing changes in magnetic fields and detection coil voltage. This approach enhances MCR-WPT system safety and efficiency, making it suitable for complex environments.

Analysis, Design, and Optimization of Segment‐Compensated PCB Coil for Multirelay Wireless Power Transfer System

ABSTRACTThis paper proposed a segment‐compensated printed circuit board (PCB) coil for multirelay wireless power transfer (WPT) system. The PCB coil is designed with variable width to improve the system transfer efficiency, and the segmented compensation method is applied to avoid the high voltage stress on resonant capacitors in case of the multirelay WPT system with a low load resistance operating at a constant voltage frequency. The segmented compensation capacitors are integrated into the PCB coil, so as to constitute the compact coupler used in multirelay WPT system. The optimization procedure of the segment‐compensated PCB coil is also provided. The quality factor of the PCB coil can be improved by optimizing the proportional coefficients of width variation. The voltage of capacitors can be reduced by optimizing the number of segments. A physical variable‐width PCB coil with 3 segments is constructed. The experimental prototypes of the three‐coil, four‐coil, and five‐coil WPT systems are built. The experimental results show that the voltage of the segmented compensation capacitors on each coil is almost uniformly distributed and does not exceed 250 V when the input voltage is 50 V and the load resistance is 10 Ω. Compared with the multirelay WPT system using the equal‐width PCB coil, the multirelay WPT system using the PCB coil designed in this paper has higher output power and higher efficiency.

Array of Active Shielding Coils for Magnetic Field Mitigation in Automotive Wireless Power Transfer Systems

This paper deals with the mitigation of magnetic field levels produced by a wireless power transfer (WPT) system to recharge the battery of an electric vehicle (EV). In this work, an array of active coils surrounding the WPT coils is proposed as a mitigation technique. The theory and new methodological aspects are the focus of the paper. Magnetic field levels in the environment are calculated numerically without and with the presence of an array of active coils in a stationary WPT system for automotive applications. By the proposed mitigation method, the field levels beside the vehicle are significantly reduced and comply with the reference levels (RLs) of the ICNIRP 2010 guidelines for human exposure to electromagnetic fields and the magnetic flux density limits proposed by ISO 14117 for electromagnetic interference (EMI) in cardiac implantable electronic devices (CIEDs).

Two-dimensional ferrite core-based transmitting coil for wireless power transfer in novel capsule robots

Two-dimensional ferrite core-based transmitting coil for wireless power transfer in novel capsule robots

Hybrid PVP/Battery/Fuel Cell Wireless Charging Stations Using High-Frequency Optimized Inverter Technology for Electric Vehicles

The design and integration of intelligent energy management systems in hybrid electric vehicle (EV) charging stations, leveraging industry 4.0 and renewable energy sources, is crucial for advancing sustainability, efficiency, and technological development. The innovative hybrid EV charging station described in this study uses a combination of fuel cells, batteries, and solar panels that run at 14 amps a piece at 240 volts. The system consists of five essential components that work together to transfer power wirelessly: an EV battery bank, a boost converter, an HF inverter, transfer coils, and a power supply. Two crucial phases make up the optimization process. In phase 1, the boost converter’s maximum power point is tracked and optimized to generate the most power possible by varying the duty cycle between 10% and 90%. In phase 2, the HF uses a class ϕ2 inverter at 30 MHz to synchronize with the resonant frequency of wireless power transfer coils. Zero-voltage switching is used by a digital signal processor card to carry out control for effective operations. By utilizing hybrid sources to optimize power transmission, this design improves the sustainability of EV charging options.

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.

A Novel Type of Transmitter with A-R Coil for Large-Scale Spatial Wireless Power Transfer

A Novel Type of Transmitter with A-R Coil for Large-Scale Spatial Wireless Power Transfer

Design and Optimization of Unequal-Pitch SelfResonant Helical Coils for High-Efficiency MidRange Wireless Power Transfer

Design and Optimization of Unequal-Pitch SelfResonant Helical Coils for High-Efficiency MidRange Wireless Power Transfer

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