Wireless Power Transfer Technology Research Articles

Wireless Powered Surface Acoustic Wave Platform for Achieving Integrated Functions of Fogging/Icing Protection and Monitoring.

In this study, we introduced an integrated approach using piezoelectric thin film-based surface acoustic wave (SAW) and wireless power transfer (WPT) technologies, designed for both passive monitoring and active defogging/icing functions. We systematically investigated the resonant frequency shifts of ZnO/glass SAW devices, establishing their correlations with variations in humidity and temperature under cold conditions. Acoustic waves generated through the ZnO/glass SAW device were used for defogging and deicing functions with effects of RF powers and acousto-heating thoroughly evaluated. More significantly, the WPT system was successfully applied for achieving defogging and deicing functions, with its performance comparable to that of conventional wired SAW systems. Our findings demonstrated that the WPT SAW system significantly minimizes localized acousto-heating effects, although the time taken for both defogging and deicing was slightly longer than the wired system. This work represents a significant advancement in developing multifunctional, optically compatible, and wireless-integrated solutions for SAW based ice protection.

High-Efficiency Microwave Wireless Power Transmission via Reflective Phase Gradient Metasurfaces and Surface Wave Aggregation.

Microwave Wireless Power Transfer (MWPT) technology is crucial for emergency power supply during natural disasters and powering off-grid equipment. Traditional antenna arrays, however, suffer from low energy capture efficiency, difficult impedance matching, complex synthetic networks, and intricate manufacturing processes. This paper introduces a microwave energy receiver design utilizing Reflective Phase Gradient Metasurfaces (R-PGMs) and surface wave energy convergence technology. The design leverages the effective plane wave-to-surface wave conversion capability of R-PGMs to transform incident microwave energy into a surface wave mode, which is then efficiently harvested using a circular energy convergence array before being output to a coupling port. By optimizing R-PGM parameters, an ideal 60° phase gradient distribution is achieved, facilitating the focus of surface wave energy via dispersion characteristics. These components are integrated into a hybrid antenna array, complemented by a matched energy output port structure. Numerical simulations show that this array can efficiently convert microwave energy from plane waves to surface waves, achieving a conversion efficiency of 85.32% and a collection efficiency of 68.26%. Experimental results corroborate these findings, with peak energy collection efficiency reaching 64.68% at 5.8 GHz and an RF-DC conversion efficiency of 42%, confirming the design's efficacy. Compared to conventional methods, this design simplifies the system by avoiding complex combining networks and significantly enhances the efficiency of microwave MWPT.

A Power Boosting Method for Wireless Power Transfer Systems Based on a Multilevel Inverter and Dual-Resonant Network

With the deepening of research on wireless power transfer (WPT) technology, there is an urgent need to improve the output power of WPT systems. Therefore, this paper proposes a power boosting method based on a multilevel inverter and dual-resonant network. The system adopts a five-level inverter whose output voltage contains rich fundamental and harmonic components. The transmitting side adopts a dual-resonant compensation network, and, through its parameter configuration, the system can be in a resonant state at both the fundamental and third harmonic frequencies. The receiving side adopts two receiving channels which can simultaneously receive power at both frequencies, thus boosting the output power. Firstly, the overall structure and operating principle of the system are introduced. Then, the relationship between the system output power and efficiency with the inverter modulation parameters is obtained and the strategy for selecting the optimal operating points of the inverter is designed by comprehensively considering the THD of the inverter output voltage and the efficiency of the system. Furthermore, the proposed system is simulated in a Matlab/Simulink platform. Finally, an experimental setup is created to verify the proposed method. The results show that, compared with the single-channel WPT system, the proposed method can enhance the output power from 160 W to 310 W with a boosting coefficient of nearly double and with the highest efficiency exceeding 92%.

A Review on the Recent Development of High-Frequency Inverters for Wireless Power Transfer

With the demand for the miniaturization and integration of wireless power transfer (WPT) systems, higher frequency is gradually becoming the trend; thus, the power electronic device has become one of the main reasons for limiting the development. Therefore, further research on high-frequency inverters and purposeful design according to the characteristics of WPT systems are of great significance to promote the development of high-frequency WPT technology. There is still no literature that summarizes all the inverter circuits that can be applied to WPT systems, which makes it extremely difficult to find an inverter that meets the designer’s requirements. This paper reviews the high-frequency inverters for WPT systems, summarizes the derived topologies based on power amplifiers and H-bridge inverters, investigates the main factors restricting the development of high-frequency inverters, and analyzes the research directions for future development.

Effect of cell structures on electrical degradation of GaAs laser power convertors after 1 MeV electron irradiation and structure-optimization for improving radiation resistance

Laser wireless power transfer (LWPT) technology holds significant promise for wireless power transmission in space, necessitating that high-efficiency GaAs laser power convertors (LPCs) have strong tolerance to high-energy particle radiation. Therefore, the degradation characteristics of GaAs LPCs with different architectures under 1 MeV electron irradiation were investigated. Experimental and simulation results demonstrate that LPCs with thicker bottom cells suffer from significantly more electrical degradation. The degradation is primarily due to a reduction in electron concentrations in the base of the bottom cells, which is considerably less pronounced as the thickness of the bottom cells decreases. Based on these analyses, thinning the thickness and optimizing the doping profile for the bottom cells are proposed to improve the radiation resistance of the LPCs. Simulations show that the electrical degradation of the optimized four-junction LPCs is notably less than that of the original four-junction LPCs under the same irradiation conditions, indicating that the proposed strategies effectively enhance the radiation resistance of the LPCs.

A Compact Broadband Rectifier Based on Coupled Transmission Line for Wireless Power Transfer

Wireless Power Transfer (WPT) can effectively solve the problem of autonomous power supply for low-power devices. Rectifier is the key component in WPT technology. In this paper, a novel impedance matching network for the broadband rectifier is proposed. This impedance matching network compensates for the diode impedance and reduces its impedance change when the frequency or input power changes. The passive boosting mechanism utilizing coupled transmission lines (CTLs) improves the power conversion efficiency (PCE) of the diode in the low power region. The structure is especially optimized for low-power device applications. For validation, a broadband rectifier operating at 1.9–3 GHz is fabricated and measured. The structure fabricated on the Rogers 4003 substrate with a thickness of 1.508 mm and the diode is HSMS2860. The DC voltage Vout on the load (RL=1300 Ω) was measured. The results show that at 0 dBm, the PCE keeps more than 60% at 1.98–3 GHz. The peak PCE of 79.6% is obtained at 4 dBm. The compact size of the broadband rectifier is 19 mm × 21 mm. This broadband rectifier for low input power ranges can be applied to WPT technology.

Jointly Optimization of Delay and Energy Consumption for Multi-Device FDMA in WPT-MEC System.

With the rapid development of mobile edge computing (MEC) and wireless power transfer (WPT) technologies, the MEC-WPT system makes it possible to provide high-quality data processing services for end users. However, in a real-world WPT-MEC system, the channel gain decreases with the transmission distance, leading to "double near and far effect" in the joint transmission of wireless energy and data, which affects the quality of the data processing service for end users. Consequently, it is essential to design a reasonable system model to overcome the "double near and far effect" and make reasonable scheduling of multi-dimensional resources such as energy, communication and computing to guarantee high-quality data processing services. First, this paper designs a relay collaboration WPT-MEC resource scheduling model to improve wireless energy utilization efficiency. The optimization goal is to minimize the normalization of the total communication delay and total energy consumption while meeting multiple resource constraints. Second, this paper imports a BK-means algorithm to complete the end terminals cluster to guarantee effective energy reception and adapts the whale optimization algorithm with adaptive mechanism (AWOA) for mobile vehicle path-planning to reduce energy waste. Third, this paper proposes an immune differential enhanced deep deterministic policy gradient (IDDPG) algorithm to realize efficient resource scheduling of multiple resources and minimize the optimization goal. Finally, simulation experiments are carried out on different data, and the simulation results prove the validity of the designed scheduling model and proposed IDDPG.

Optimizing Wireless Power Transfer Systems: A Simulation-Based Approach Using CST Studio Suite

In the rapidly evolving field of wireless power transfer (WPT), achieving systems that combine efficiency with reliability is crucial. This paper presents a simulation-based approach using CST Studio Suite to optimize WPT systems for wireless battery chargers in electric bikes. The study fixes the size of both the transmitter and receiver coils, the spacing between turns, and the number of coil turns, with a set distance of 20mm between the transmitter and receiver coils. CST Studio Suite is employed to determine the parameters of resonance capacitors and the optimal switching frequency to enhance WPT efficiency. This powerful simulation tool allows researchers and engineers to design resonance compensation circuits more effectively, optimizing power transfer efficiency. The simulation conducted with CST Studio Suite confirms its effectiveness in designing a WPT system, achieving an impressive peak efficiency of 99.61% at the resonant frequency. The paper demonstrates CST Studio Suite's capability to accurately predict WPT system performance by developing detailed electromagnetic models and fine-tuning simulation parameters to reflect real operating conditions. Iterative simulations resulted in optimized practices, validated by select results that highlight the method's effectiveness and showcase an optimal balance between system complexity and efficiency. These findings provide a strategic framework for future WPT system development, offering practical guidance for researchers and industry professionals aiming to advance WPT technology.

Wireless Power and Data Transfer Technologies for Flexible Bionic and Bioelectronic Interfaces: Materials and Applications

Wireless Power and Data Transfer Technologies for Flexible Bionic and Bioelectronic Interfaces: Materials and Applications

Advancements in electrical systems for E-bike battery charging: a technical examination of conventional and wireless power transfer technologies

Advancements in electrical systems for E-bike battery charging: a technical examination of conventional and wireless power transfer technologies

Optimising Electric Flex-Route Feeder Transit Service with Dynamic Wireless Charging Technology

The emergence of battery electric buses (BEBs) can alleviate environmental problems caused by tailpipe emissions in transit system. However, the high cost of on-board batteries and range anxiety hinder its further development. Recently, the advent of dynamic wireless power transfer technology (DWPT) has become a potential solution to promote the development of BEBs. Hence, this study focuses on the application of DWPT in flex-route transit system. A mixed integer non-linear model is proposed to simultaneously optimise the bus routing and the selection of corresponding bus types considering the constraints of passengers’ travel time, battery size and bus capacity. The objective is to minimise both transit agency cost and passengers’ travel time cost. A tangible hybrid variable neighbourhood search (HVNS) consisting of simulated annealing (SA) and variable neighbourhood search (VNS) is developed to solve the proposed model efficiently. Compared with GAMS (DICOPT solver) and VNS, the proposed algorithm can considerably improve computational efficiency. The results suggest that the proposed model can effectively determine the BEBs’ routing and bus type for flex-route transit system powered by DWPT through a case study in Xi’an China. A comparative analysis shows the proposed model takes 12.97% less total cost than the alternative model with terminal charging technology (TCT).

Performance Improvement of Wireless Power Transfer System for Sustainable EV Charging Using Dead-Time Integrated Pulse Density Modulation Approach

The recent developments in electric vehicle (EV) necessities the requirement of a human intervention free charging system for safe and reliable operation. Wireless power transfer (WPT) technology shows promising options to automate the charging process with user convenience. However, the operation of the WPT system is designed to operate at a high-frequency (HF) range, which requires proper control and modulation technique to improve the performance of power electronic modules. This paper proposes a dead-time (DT) integrated Pulse Density Modulation (PDM) technique to provide better control with minimal voltage and current ripples at the switches. The proposed technique is investigated using a LCC-LCL compensated WPT system, which predominantly affects the high-frequency voltage and current ripples. The performance analysis is studied at different density conditions to explore the impact of the integrated PDM approach. Moreover, the PDM technique gives better control over the power transfer at different levels of load requirement. The simulation and experimental analysis was performed for a 3.7 kW WPT prototype test system under different modes of operation of the high-frequency power converters. Both the simulated and experimental results demonstrate that the proposed PDM technique effectively enhances the efficiency of the HF inverter while significantly reducing output current ripples, power dissipation and improving the overall WPT system efficiency to 92%, and leading to a reduction in the power loss in the range of 10% to 20%. This leads to improved overall system control and performance.

Sizing Methodology of Dynamic Wireless Charging Infrastructures for Electric Vehicles in Highways: An Italian Case Study

The necessity of pushing the road mobility towards more sustainable solutions has become of undeniable importance in last years. For this reason, both research and industry are constantly investigating new technologies able to make the usage of battery electric vehicles(BEV) as accessible and usable as traditional internal combustion engine vehicles (ICEV). One of the most limiting issues concerns the short range of electric vehicles, which complicates their use for long distances, such as for highway travels. A promising solution seems to be the “charge-while-driving” approach, by exploiting the inductive dynamic wireless power transfer (DWPT) technology. Nevertheless, such systems show different issues, first of all, high investment and maintenance costs. Furthermore, it is not clear how extensive a potential dynamic wireless charging infrastructure needs to be to make a real advantage for electric vehicle drivers. As a consequence, the aim of this paper is to introduce a new methodology to estimate the number and length of wireless charging sections necessary to allow the maximum number of electric vehicles to travel a specific highway without the need to stop for a recharge at a service area. Specifically, the methodology is based on a algorithm that, starting by real traffic data, simulates vehicle flows and defines the basic layout of the wireless charging infrastructure. This simulator can provide a decision support tool for highway road operators.

Wireless Electric Vehicle Charging System using Solar Energy

Abstract: The proliferation of electric vehicles (EVs) has spurred the need for efficient and sustainable charging solutions. This paper presents the design and implementation of a wireless EV charging system integrating solar energy harvesting and Arduino-based control. The proposed system aims to provide convenient and eco-friendly charging for EVs while minimizing reliance on grid electricity. The core components of the system include photovoltaic panels for solar energy capture, wireless power transfer technology for cordless charging, and Arduino microcontrollers for system control and monitoring. By harnessing solar energy, the system reduces dependence on conventional power sources, thereby lowering carbon footprint and operating costs.

Modeling and Transmission Characteristics Study of a Resonant Underwater Wireless Electric Power Transmission System

Compared to the traditional wet-mate underwater power supply method, Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology boasts advantages such as excellent insulation, high safety, and convenient operation, showing promising application prospects in the field of power supply for underwater vehicles and other mobile underwater devices. In order to explore the transmission characteristics of this technology underwater, this article first establishes a traditional mathematical model, and then modifies the underwater model through analysis of changes in coil self-inductance and mutual inductance, as well as the impact of eddy current losses. Using the modified mathematical model of the underwater MCR-WPT system, the transmission characteristics are analyzed, and simulations and experimental validations are performed using MATLAB R2022a software. In the study of frequency characteristics, it is found that the system operates optimally when both ends of the circuit work at the resonant state; that is, when finput = fresonance = 100 kHz, the output performance is at its best, and the optimal resonant frequency significantly improves power and transmission efficiency. When the input frequency is less than 87.3 kHz or greater than 122.9 kHz, the output power decreases to less than half of the maximum power. In the investigation of load effects, the optimal load for maximizing system output power was identified, but the load that maximizes transmission efficiency is different from this optimal load. This study provides strong theoretical support and guidance for improving the performance of underwater wireless power transmission systems.

Multi-Objective Optimization Study on the Coupling Mechanism of Underwater Wireless Power Transfer Systems

Magnetically coupled resonant wireless power transfer (MCR-WPT) technology offers longer effective transmission distances and higher efficiency compared to traditional charging methods, making it better suited to the prolonged and efficient operation of autonomous underwater vehicles. This paper first establishes a traditional mathematical model and then refines it while analyzing the variations in the self-inductance and mutual inductance of underwater coils. To further enhance the system’s performance, a multi-objective optimization of the coupling mechanism is conducted. An orthogonal experiment is employed to determine the effects of various influencing factors on the coils’ self-inductance and mutual inductance. Subsequently, an RBF neural network is used to create a regression prediction model based on the results of the orthogonal experiment. The NSGA-II algorithm is then applied for the multi-objective optimization of the coupling mechanism, resulting in a Pareto front solution set. The optimized efficiency is 93.35%, representing an approximately 6% improvement over the original system, with the power density increasing from 1.267×106 W/m3 before optimization to 4.782×106 W/m3 after optimization. Significant enhancement in system performance is achieved.

Power boundaries in resonant electrodynamic wireless power transfer systems

This article focuses on deriving the maximum power that can be transmitted using recent wireless power transfer technology based on an electrodynamic receiver. Analytical derivations reveal two main constraints that can limit transmitted power: the magnetic field safety limit and the maximum stress before breaking the receiver. From these limits, expressions of maximum magnetic forces and power are derived, providing physical insights on how to optimize the transmitted power. Interestingly, the optimal electrical condition and the optimal electromechanical efficiency differ when maximizing the transmitted power under each constraint. In the final section of the paper, the proposed theoretical boundaries are applied to two types of receivers, based on either electromagnetic or piezoelectric transducers. The results demonstrate that the maximum power density achievable with both receivers is inherently limited (<10 mW/cm3) under realistic assumptions regarding electromechanical coupling and electrical circuitry. This value is smaller than some previously reported results involving rotating or magnetoelectric solutions, indicating that clamped-free beams are not the optimal solution for electrodynamic wireless power transfer. This analysis can be extended to other types of receivers and will be useful for optimizing, sizing, and assessing any technological solution for wireless power transfer.

Security Performance Analysis of Full-Duplex UAV Assisted Relay System Based on SWIPT Technology

In this paper, a new methodology is developed for modeling and analyzing a full-duplex UAV-assisted relay system to facilitate solving the problems of UAV energy constraints and the vulnerability of UAVs to eavesdropping in the air. Combining simultaneous wireless information and power transfer (SWIPT) technology, we model the downlink UAV eavesdropping channel and propose a secure transmission protocol for a full-duplex UAV-assisted relay system. Using this transmission protocol, we analyze and derive the connectivity and security of the entire communication link, including connection probability and lower bounds on secrecy outage probability. A key intermediate step in our analysis is to derive the signal-to-digital noise ratio of the destination and eavesdropping nodes of the full-duplex UAV relay link. The analyses show that the power allocation factor λ is a trade-off between system connectivity and security, while greater eavesdropping interference needs to be sacrificed for an equal magnitude of security performance improvement under high security demand conditions.

Design and validation of a DC–DC converter-based inductive power transfer system with increased efficiency and reduced voltage stress across switches

Research in wireless power transfer(WPT) focuses on improving efficiency, reducing energy consumption, improving safety, and increasing sustainability. It prioritises developing more efficient transmission technologies, such as high-frequency switching and resonant coupling, to enhance the system’s overall performance. However, high voltage stress across the semiconductor devices during switching operations at high frequencies can result in increased switching loss, leading to decreased overall efficiency of the WPT system. The switching loss can be minimised by reducing voltage stress, resulting in higher efficiency and improved energy transfer performance. This leads to more cost-effective WPT solutions without compromising performance or reliability by using lower-rated components and reducing the need for elaborate voltage clamping and protection circuits. Lowering voltage stress across switches can also help WPT systems comply with industry standards and regulations related to electrical safety, electromagnetic compatibility (EMC), and energy efficiency. Meeting these standards is essential for ensuring the widespread adoption and commercial success of WPT technology. In this article, a class ø2 inverter and a modified class-E rectifier is integrated and applied in a WPT system. The benefits of a Resonant class ø2 inverter are zero voltage switching(ZVS) and lower switch voltage stress as compared to its predecessors. Also, a resonant class E/F3 rectifier inductively coupled in the receiving stage reduces the peak voltage stress across the diode. The system shown here is tuned to achieve maximum overall transfer efficiency. The proposed class ø2-E/F3 combined WPT system operating at 50 kHz simulated in PSIM software yielded a dc-dc efficiency of 94.56 percent, and the peak voltage stress across switches is found to reduced (2.4–2.7 times the input voltage as compared to the existing topologies where it surges upto 3.6–4 times the input voltage). These are also validated in Typhoon HIL’s Real-Time Emulator HIL402. In addition to that, a machine learning algorithm based on an Artificial Neural Network is used to generate a model to predict the switching frequency for a specified output voltage and efficiency.

Discharging driven energy sharing protocol for V2V communication in vehicular energy networks

With the growing concern over range anxiety among electric vehicle (EV) owners due to limited battery capacity and sparse charging infrastructure, EV-to-EV (V2V) energy sharing emerges as a crucial solution to extend driving range. Leveraging the vehicular energy network (VEN) enabled by dynamic wireless power transfer (DWPT) technology, energy sharing among EVs in motion becomes feasible. However, the effective establishment of communication and identification of suitable V2V energy sharing pairs pose significant challenges, particularly for EVs with discharging demands. To address this challenge, we propose a new discharging driven energy sharing protocol based on vehicular ad-hoc networks (VANETs). Firstly, we present a routing approach for transmitting discharging information through VANETs, considering key factors such as distance, state of charge, number of neighbor vehicles, and vehicle speed. This routing scheme facilitates efficient relay node selection on road segments and intersections, ensuring optimal communication paths. Subsequently, we formulate a charging requester selection model to identify the most suitable requester for energy sharing. This model optimizes individual utility while accounting for the state of charge of the requesters, ensuring a comprehensive and inclusive approach to V2V energy sharing. Finally, we develop an acknowledgment message transmission scheme to ensure the completion of selection acknowledgment between discharging EVs and charging EVs. This scheme includes provisions for recovery in case of forwarding link failures, ensuring robust communication in dynamic vehicular environments. Extensive simulations conducted using network simulator 2 (NS-2) demonstrate the superior performance of the proposed protocol in terms of packet delivery ratio, end-to-end delay, and overall V2V energy sharing efficiency.