Wireless Energy Transfer Research Articles

Characterization Of Resonant Coupled Inductor In A Wireless Power Transfer System

Wireless power transfer (WPT) has garnered significant interest as a potentially transformative technology in the energy sector, as it presents a novel approach to powering and charging devices. The functionality of this technology is predicated upon the utilization of electromagnetic coupling to facilitate the wireless transmission of energy between two entities. Despite the considerable potential, wireless power transfer (WPT) faces significant obstacles that restrict its practical feasibility. One notable challenge that arises is the decrease in power transfer efficiency as the distance between the transmitter and receiver increases. Moreover, the Wireless Power Transfer (WPT) technology is further limited by its reliance on accurate alignment between the transmitting source and the receiving device, thereby posing challenges for its practical implementation. The issues present substantial obstacles to the widespread commercialization of wireless power transfer (WPT). This study seeks to improve the efficacy of power transfer by optimizing the resonance frequency of the power transfer in response to the challenges. By systematically manipulating various parameters, including coil dimensions, input voltage levels, and operational frequency, a novel approach is proposed to enhance the efficiency of power transfer. The study additionally offers valuable insights regarding the correlation between the distance separating the coils and the efficiency of power transfer. The findings of this study offer a thorough empirical analysis and are supported by a strong theoretical framework, resulting in a substantial coefficient of determination (R² = 0.937118). This finding suggests that the linear regression model under consideration could account for approximately 93.7118 percent of the variability observed in the distance. The findings of this study establish a pathway towards enhanced and feasible wireless power technology, thereby establishing a robust basis for the prospective commercial implementation of wireless power transfer (WPT) systems.

A new efficiency figure of merit for induction heating appliances operating under highly variable operating conditions

Induction heating is an efficient and high-performance heating method which already has a significant market penetration and economic impact due to its benefits inherent to contactless energy transfer systems such as quickness, cleanness, and safety. Efficiency is a key design parameter since it determines not only the appliance performance but also its environmental impact, with significant socio-political implications. However, it is not easy to determine and compare the actual power converter efficiency operating under highly variable conditions typical of IH. This paper proposes an averaged efficiency parameter elaborated based on technical and typical IH usage conditions that offers a useful value to compare power converters operating under realistic operation conditions. The proposed parameter has been evaluated in some of the most significant power converter topologies used in reported state-of-the-art induction heating systems.

Weighted fair energy transfer in a UAV network: A multi-agent deep reinforcement learning approach

Flying Energy Sources (FESs) have been proven highly effective in transferring energy to battery-powered Unmanned Aerial Vehicles (UAVs). Such wireless transfer techniques in the literature were able to extend the flight duration of UAVs; however, they overlooked the fair distribution of energy among UAVs, which is of utmost importance for supporting diverse application demands. In this work, we quantify the urgency level of a UAV following its application responsibility, energy charging, and drainage rates and develop a framework for optimal energy transfer from FESs to UAVs in a weighted-fair way. Even though the developed framework can promote a highly balanced and fair energy distribution, its computation cannot always be done in polynomial time. Alternatively, to achieve a real-time solution, we further develop a Multi-Agent Deep Deterministic Policy Gradient (MADDPG) algorithm, namely AERIAL, to effectively model the complex interactions and dependencies among the UAVs and FESs and improve the wireless energy transfer process. The AERIAL system is implemented in the OpenAI Gym simulator platform and its performances have been compared with the state-of-the-art approaches. As high as improvements of 25.2% in fairness and 19.4% in average energy level demonstrated by the AERIAL system prove its effectiveness.

Thermal stability of triple-junction gallium arsenide cells.

Laser wireless power transmission (LWPT) systems have significant applications in the field of wireless energy transmission, including spacecraft sensor networks, satellite-to-satellite communication, and remote power supply. However, continuous laser exposure increases the temperature of the photovoltaic (PV) cells in the LWPT system, thus decreasing the electrical output performance. This work, which we believe is a new approach, is on the basis of a notch film designed by a combined merit function proposed to maintain the electrical output performance while under 1064-nm continuous laser irradiation. Moreover, the thermal stability of PV cells under laser irradiation was investigated, which revealed the recoverability of the open-circuit voltage (Voc) of the cells at different temperatures, and the thermal damage to cells was a gradual process. This process began with the vaporization of the encapsulation adhesive, followed by a decline in, but still recoverable and functional, electrical performance, and finally, the cell was completely damaged. The thermal stability of the PV cells coated with the notch film increased ten-fold compared to those without it. Furthermore, the correlation between the minimum Voc and maximum temperature of the cells with notch films of different performances was established. These investigations serve as references for further optimization of LWPT.

The Heterogeneous Packaging of A 3 × 3 Mini‐LED Array for Smart Contact Lens Display Applications

For the needs of augmented reality (AR), virtual reality (VR) and mixed reality (MR), smart contact lenses (SCL) have become an important platform as a display source in the future consumer market. Accordingly, this paper demonstrates a display device based on contact lenses. This device integrates a 3 × 3 Mini‐LED display array, a micro antenna, and a driver and transmission chip and is packaged in a smart contact lens made of hydroxyethyl methacrylate (HEMA). It is note that in order to simultaneously meet the goals of wearing comfort, biocompatibility, wireless energy transmission and adjustable display functions, the final package thickness needs to be less than 200 μm. Here, we use heterogeneous packaging technology to connect the driver and transmission chip and the Mini‐LED display array with metal wires on the flexible substrate, and use metal wires on the same conductive layer to design the antenna required for wireless energy transmission. In order to complete the above functions, we use 920 MHz RFID technology as the energy source for wireless energy transmission. When the antenna of the RFID reader is 2 cm away from the smart contact lens, the designed receiving chip can receive 100 μW of energy. After converting this energy to DC 3 V, it can drive Mini‐LED with a current of about 30 μA, and the mini‐LED display array can be instantly controlled to display different contents by transmitting display commands through the RFID protocol. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Characterization of resonant coupled inductor in a wireless power transfer system

Wireless power transfer (WPT) has garnered significant interest as a potentially transformative technology in the energy sector, as it presents a novel approach to powering and charging devices. The functionality of this technology is predicated upon the utilization of electromagnetic coupling to facilitate the wireless transmission of energy between two entities. Despite the considerable potential, wireless power transfer (WPT) faces significant obstacles that restrict its practical feasibility. One notable challenge that arises is the decrease in power transfer efficiency as the distance between the transmitter and receiver increases. Moreover, the wireless power transfer (WPT) technology is further limited by its reliance on accurate alignment between the transmitting source and the receiving device, thereby posing challenges for its practical implementation. The issues present substantial obstacles to the widespread commercialization of wireless power transfer (WPT). This study seeks to improve the efficacy of power transfer by optimizing the resonance frequency of the power transfer in response to the challenges. By systematically manipulating various parameters including coil dimensions, input voltage levels, and operational frequency, a novel approach is proposed to enhance the efficiency of power transfer. The study additionally offers valuable insights regarding the correlation between the distance separating the coils and the efficiency of power transfer. The findings of this study offer a thorough empirical analysis and are supported by a strong theoretical framework, resulting in a substantial coefficient of determination (R2 = 0.937118). This finding suggests that the linear regression model under consideration could account for approximately 93.7118 percent of the variability observed in the distance. The findings of this study establish a pathway toward enhanced and feasible wireless power technology, thereby establishing a robust basis for the prospective commercial implementation of wireless power transfer (WPT) systems.

Wireless Energy Transfer with Three-Phase Magnetic Field System: Experimental Results

In this paper a three-phase magnetic field system is applied to the wireless power transfer system. The research is directed not only to the distribution of the magnetic field but to optimize the energy transfer efficiency, and to reduce the electromagnetic field influence to the surroundings. The development of the future intelligent transportation system depends on the electric mobility, namely, the individual or the public electric vehicles. It is crucial to achieve progress in the batteries and the battery charging, especially through a wireless power transfer technology. The study of the magnetic field is important in this technology. The energy transfer efficiency depends of the alignment, the size of the coils, the spatial orientation of the magnetic field, the detachment and the tilt between the windings.

Study of the requirements of an autonomous system for surface water quality monitoring

In recent years, there has been increasing awareness of the preservation, protection and sustainable use of natural resources. Water resources, being one of the most important natural resources, face major threats due to contamination by pollutants of various types and origins. Maintaining the quality of water resources requires more robust, reliable and more frequent monitoring than traditional techniques of data collection based on sporadic, discontinuous and manual processes. The management of large geographical areas, the insufficient spatiotemporal discretization of the values of samples collected by traditional processes and the unpredictability of natural phenomena, require a new approach to data collection procedures. This article, which is the result of ongoing research, defines the technical requirements and technologies used in a continuous and regular monitoring of surface water quality in freshwater systems, whose data acquisition system helps to identify the sources of pollution and the contaminants flow along the waterways. The design of a versatile real-time water quality monitoring system, which, due to its environmental constraints should be based on renewable energies and wireless transfer of energy, will contribute to improve the management and effective protection of water resources.

Simulation of Eddy Current Losses in Twisted Wires

Twisted wires made of insulated strands, known as stranded conductors or litz wires, are used in various areas where the eddy current loss within the wire needs to be reduced. These areas include induction heating, resonance-based wireless energy transfer, and certain radio frequency devices. Some litz wires consist of thousands of individual conductor strands that are twisted together in multiple stages, creating a hierarchical bundle structure. Computer simulations (typically using finite element analysis) are used in the optimal design of the bundle structure. However, detailed three-dimensional models are computationally demanding. In this work, a two-dimensional finite element model was presented for simulating the eddy current loss in cables made of twisted wires. The key element of the model is considering the bundle structure (generally referred to as 3D configuration conditions) within the cross-sectional model domain. The accuracy of the proposed model is tested against 3D finite element simulations. The new method is shown to be accurate, and its computational cost is by orders of magnitude lower than that of 3D models.

Outage performance and energy efficiency optimization of wireless-powered millimeter-wave sensor networks

AbstractWith the widespread use of wireless sensor networks, one of the most pressing concerns is extending the lifetime of the sensors. By deploying directional antenna arrays, millimeter wave (mmWave) is a possible candidate for wireless energy transfer (WPT). This paper investigates a beneficial combination of WPT and data transmission in a typical mmWave sensor network with Rayleigh channels, where a transmission interval can be divided into two sub-intervals. During the first sub-interval, one hybrid access point (HAP) employs beamforming techniques to transfer energy for serving multiple sensors within the service sector. The sensors then transmit their individual signal in turn to the HAP based on time division multiple address (TDMA) strategy by using the whole harvested energy. According to stochastic geometry, the exact and approximate expressions of beam outage probability for the considered system are determined, respectively. The optimal time allocation of energy harvesting and data transmission for sensors is examined in order to maximize the energy efficiency of the system. The optimization problem can be translated into corresponding parametric form, and the resulting optimization problem can be solved using the Lagrange dual method with Karush–Kuhn–Tucker (KKT) conditions. The numerical results show the variation trend of the beam outage probability under various parameters and verify the accuracy of the theoretical analyses. Furthermore, the simulation results illustrate that the proposed optimal time allocation strategy can significantly enhance the overall energy efficiency of the system compared with a similar scheme.

Main aspects of innovation management in the energy sector

The study is aimed at identifying the main aspects of innovation management in the energy sector. The need for research is determined by the demand for the development of the global energy sector to implement strategies for sustainable development of countries and ensure energy security. It is argued that the intensity of innovation has affected all areas of activity, including energy. Key aspects of innovation management in the energy sector are identified. Modern innovative technologies of energy saving, wireless energy transmission, and the development of renewable energy sources are classified. The role of technology companies in the implementation of innovations in the energy sector to optimize existing processes and approaches to energy generation is emphasized. The most effective innovative technologies in the energy sector have been identified: innovative energy storage; artificial intelligence in microgrids; Blockchain and renewable energy sources in the context of innovation. The need for innovation to increase efficiency and optimize processes in modern companies is brought to light. The main results of the study are characterized by the fact that the main aspects of innovation management in the energy sector are identified, which applied in practice when developing strategy for the long-term development of the energy sector.

Research on the application of wireless energy transmission technology in smart grid

Abstract With the continuous development of wireless energy transmission technology, the role of wireless rechargeable sensor networks (WRSNs) in smart grids has become more and more important. In this paper, after fully investigating the application of wireless energy transmission technology in smart grids, the solution vector of SFLA is discretized, and the IMSFLA model based on the hybrid frog jump algorithm is proposed to solve the wireless energy transmission planning problem in the smart grid. Finally, it is applied to the optimal design of the charging scheme of WRSNs, and the simulation results of the IMSFLA algorithm are compared and analyzed with those of the Taboo Search (TS) algorithm after exploring its wireless transmission performance. In terms of energy utilization, when the number of nodes is increased to 550, the energy utilization of IMSFLA algorithm is improved by 7% compared to TS algorithm, and when the number of nodes is increased to 550-800, the optimized results of TS algorithm deviates significantly more compared to IMSFLA algorithm. This indicates that the IMSFLA algorithm designed in this paper has a better effect on the optimization of the charging scheme of wireless rechargeable sensor networks, which is of great practical significance for improving the stability of the smart grid.

Wireless Energy Transfer Using Chirp Waveform With Joint Subband Selection and Max-Min Power Control for IoT Networks

Wireless Energy Transfer Using Chirp Waveform With Joint Subband Selection and Max-Min Power Control for IoT Networks

Energy and Throughput Management in Wireless Body Area Network with Wireless Information and Energy Transfer using Reinforcement Learning

Energy and Throughput Management in Wireless Body Area Network with Wireless Information and Energy Transfer using Reinforcement Learning

Intelligent Reflecting Surface Aided Simultaneous Wireless Information and Energy Transfer to IoT Users Under Spatial Correlation

Intelligent Reflecting Surface Aided Simultaneous Wireless Information and Energy Transfer to IoT Users Under Spatial Correlation

Research on 2.45 GHz Weak Energy Wireless Transmission with Tilted Groove Schottky Diodes

Energy conversion efficiency is a key index to evaluate microwave wireless energy transmission system, which indicates the capacity to transform microwave energy into direct current (DC) energy. In this paper, the primary component of the rectifier circuit design, Ge Schottky Diode (SBD), is optimized and designed from a structural standpoint in the context of wireless energy collection in the weak energy density of 2.45 GHz Wi-Fi band, with the aim of enhancing the efficiency of the rectifier circuit in the presence of weak Wi-Fi energy density. The PSPICE parameters of the designed SBD were extracted using the parameter extraction tool, and the Spice model of the developed SBD was built. Utilizing this model, the rectifier circuit was simulated using ADS to enhance its efficiency and confirm the effectiveness of the intended devices. The findings indicate a notable enhancement in the energy conversion efficiency of the new Ge Schottky diode within the weak energy working region.

Dual LCL resonance compensation for the design of electric vehicle wireless energy transmission system topology

Dual LCL resonance compensation for the design of electric vehicle wireless energy transmission system topology

Throughput maximization scheme of the IRS-aided wireless powered NOMA systems

The computation complexity of the existing resource allocation schemes to maximize sum throughput is very high for intelligent reflecting surface (IRS)-assisted wireless powered non-orthogonal multiple access (NOMA) system. Therefore, a low complexity resource allocation method to maximize sum throughput is considered by joint optimizing phase shifts and time allocation. Firstly, to reduce the variables that need to be optimized, we derive the problem with only phase shifts as variables, and further deduce optimization problem of phase shifts only for downlink wireless energy transmission (WET) process. Then, the problem of phase shifts for WET process is solved directly by transforming multi-variable optimization problem into that with single variable, and the phase shifts for the uplink wireless information transmission process are got as well with given phase shifts for WET process. Finally, with given phase shifts, the optimal time allocation is obtained by using the function extremum method. Theoretical analysis demonstrates that the proposed scheme has low computational complexity, and the simulation results show that sum throughput of the proposed scheme is no less than that of the existing schemes in the same scenario.

Linear generator for power supply to on-board consumers of high-speed magnetically levitated carriages

Background: Maglev transport is a promising mode of transport that can provide passenger and freight transportation at speeds of up to 400-500 km/h, and in the longer term – up to 1000 km/h. Active research in this area is being conducted in China, Japan, and the USA. Currently, in China and Japan, speeds of 450-500 km/h have been achieved for commercial transportation, and promising programs have been adopted for the construction of high-speed maglev tracks and the creation of rolling stock. At such speeds, one of the pressing problems is the problem of contactless energy transfer for on-board consumers located on the carriage, because it is very difficult to ensure reliable contact current collection at speeds of 450-500 km/h and above.
 Aim: development of the design, calculation and analysis of the characteristics of a linear generator of electrical energy for contactless power transfer to the moving crew of high-speed magnetically levitated transport.
 Materials and methods: to calculate the external magnetic field of the linear generator inductor and the EMF induced in the receiving coil of the crew, methods of electromagnetic field theory and electrical circuit theory were used; calculation algorithms are implemented in the Visual Basic for Applications software environment.
 Results: a design was proposed and the calculation of the external magnetic field of an inductor with transposition of conductors was performed; to increase the EMF induced in the receiving coil of the crew, it is proposed to give the receiving coil a double 8-shape; the most rational inter-circuit distance of the linear generator inductor has been established; the nature of the change in the magnetic flux penetrating the receiving coil when the vehicle moves, and the magnitude of the emf induced in the receiving coil are determined.
 Conclusion: the results can be used in the development of rolling stock for promising high-speed maglev transport systems.

Design and Performance Analysis of New Coupling Magnetic Core Structure for Dynamic Wireless Charging System of Electric Vehicle

Aiming at the problems of high cost, low efficiency, low power, and high electromagnetic radiation in the dynamic wireless charging system for electric vehicles (EVs), the cover‐like coupling structure and the return‐like coupling structure are designed, and the unique concave structure has excellent engineering practicability. Using Ansoft software for simulation and analysis, the newly proposed two coupling structures have significantly improved the induced voltage and electromagnetic induction strength at the pickup end compared with other commonly used coupling core structures. According to the advantages of practical applications, the application of its composite core structure for simulation and analysis proves that the cover‐like structure of the magnetic field strength at the pickup end not only enhances the magnetic field strength on the coil but also has a good magnetic field shielding effect. The lateral displacement of the EV is kept within the range of 10 cm, the coupling distance is 0–5 cm, the charging is stable, and the transmission efficiency is high. Finally, a dynamic wireless charging experimental platform for small EVs is constructed, which verifies that the new coupling core structure can significantly improve the transmission power and efficiency of the charging system and significantly reduce the economic cost.