Wireless Power Transfer Technology Research Articles

Wireless Power Transfer for Unmanned Underwater Vehicles: Technologies, Challenges and Applications

Unmanned underwater vehicles (UUVs) are key technologies to conduct preventive inspection and maintenance tasks in offshore renewable energy plants. Making such vehicles autonomous would lead to benefits such as improved availability, cost reduction and carbon emission minimization. However, some technological aspects, including the powering of these devices, remain with a long way to go. In this context, underwater wireless power transfer (UWPT) solutions have potential to overcome UUV powering drawbacks. Considering the relevance of this topic for offshore renewable plants, this work aims to provide a comprehensive summary of the state of the art regarding UPWT technologies. A technology intelligence study is conducted by means of a bibliographical survey. Regarding underwater wireless power transfer, the main methods are reviewed, and it is concluded that inductive wireless power transfer (IWPT) technologies have the most potential. These inductive systems are described, and their challenges in underwater environments are presented. A review of the underwater IWPT experiments and applications is conducted, and innovative solutions are listed. Achieving efficient and reliable UWPT technologies is not trivial, but significant progress is identified. Generally, the latest solutions exhibit efficiencies between 88% and 93% in laboratory settings, with power ratings reaching up to 1–3 kW. Based on the assessment, a power transfer within the range of 1 kW appears to be feasible and may be sufficient to operate small UUVs. However, work-class UUVs require at least a tenfold power increase. Thus, although UPWT has advanced significantly, further research is required to industrially establish these technologies.

Development of soft magnetic composites for magnetized pavement to improve the efficiency of electric vehicle's wireless power transfer

Integrating the wireless power transfer (WPT) system into the pavement is an effective way to solve the inconvenience of electric vehicles (EVs)’ charging, accelerating the growth of ownership of EVs to achieve net carbon zero in transportation. However, the existence of a cement paving layer between coils was a negative impact factor. Here, two types of ferrite powders were separately mixed into the cement to prepare soft magnetic composite (SMC) material to enhance the coupling degree of coils. The magnetic and mechanical performance of the composite were tested by a vibrating sample magnetometer and compressive and flexural strength tester. Furthermore, to explore the optimal layout of the magnetized pavement structure, nine pavement layouts were designed based on the distribution of magnetic flux. Finally, the effect of SMC material on improving the charging performance was verified by WPT system test platform. Results showed that the Ni–Zn ferrite powder exhibited superior magnetic permeability due to its stronger magnetic moments and lower magnetic domain wall energy compared to Mn–Zn ferrite powder. The peak relative permeability of SMC materials reached 14.370 with an equal mass ratio of Ni–Zn ferrite powder to cement. Conversely, optimal strength was attained with a Mn–Zn ferrite to cement ratio of 0.2, resulting in a compressive strength of 36.0 MPa and a flexural strength of 4.0 MPa. Strategically placing SMC within the pavement, both in the core's interior and exterior to the coil, enhanced the coupling coefficient of coils, thereby improving the transmission efficiency of the WPT system. The incorporation of Ni–Zn ferrite powder in a 1:1 mass ratio to cement materialized the highest efficiency. Nonetheless, considering the mechanical performance, the SMC material with a 0.6 mass ratio of Mn–Zn ferrite powder to cement was recommended for magnetized pavements. The WPT system test results showed a transmission efficiency of 89.78% when utilizing magnetized pavement, surpassing the efficiency with the whole pavement material by 1.36%, which indicated great value and potential in energy conservation and carbon reduction of employing magnetized pavement in WPT technology.

Wireless Power Transfer Efficiency Optimization Tracking Method Based on Full Current Mode Impedance Matching.

Wireless power transfer (WPT) technology is a contactless wireless energy transfer method with wide-ranging applications in fields such as smart homes, the Internet of Things (IoT), and electric vehicles. Achieving optimal efficiency in wireless power transfer systems has been a key research focus. In this paper, we propose a tracking method based on full current mode impedance matching for optimizing wireless power transfer efficiency. This method enables efficiency tracking in WPT systems and seamless switching between continuous conduction mode and discontinuous mode, expanding the detection capabilities of the wireless power transfer system. MATLAB was used to simulate the proposed method and validate its feasibility and effectiveness. Based on the simulation results, the proposed method ensures optimal efficiency tracking in wireless power transfer systems while extending detection capabilities, offering practical value and potential for widespread applications.

A robust parity‐time‐symmetric hybrid wireless power transfer system with extended coupling range

SummaryInductive power transmission (IPT) and capacitive power transmission (CPT) are currently the two main wireless power transfer technologies. Hybrid power transmission (HPT) systems that combine IPT and CPT can improve transmission performance and are more attractive for some charging applications such as electric bicycles (e‐bikes). However, HPT systems are more sensitive to parameter variations, and the coupling mechanism is prone to misalignment during wireless charging. Therefore, achieving stable output power and constant transfer efficiency over a wide range of coupling coefficient variations is still a major challenge for HPT systems. In this work, the parity–time (PT) symmetry theory is applied to an SS‐type HPT system, and a circuit model of the PT‐based HPT system is developed by using coupling capacitance and coupling inductance. The effect of connecting the plates to the homonymous end or heteronymous end of the coupling coils on the PT symmetry range of the HPT system is discussed. It is found that the heteronymous end connection of the coils can effectively increase the range of constant output power and stable transfer efficiency. Finally, a prototype is built to verify the feasibility and effectiveness of the proposed PT‐based HPT system. The transfer power and efficiency remain constant in the PT‐symmetric range, and the inductive and capacitive coupling coefficients are smaller compared to IPT and CPT systems with the same parameters.

Analyzing the Mechanical Response of a Calibrated Finite Element Model for Flexible Pavement with Embedded Dynamic Wireless Power Transfer Technology

Analyzing the Mechanical Response of a Calibrated Finite Element Model for Flexible Pavement with Embedded Dynamic Wireless Power Transfer Technology

LazyFrog: Advancing Security and Efficiency in Commercial Wireless Charging with Adaptive Frequency Hopping.

With the proliferation of electronic devices and electricity-based mobility solutions, the significance of wireless power transfer technology has increased substantially. However, ensuring secure and reliable power transmission to authorized users remains a significant challenge. Addressing this complex issue requires an integrated approach that balances efficiency, stability, and security considerations. While current efforts primarily focus on improving charging efficiency and user convenience, integrating robust security measures into wireless charging infrastructure is challenging due to its inherently open nature and susceptibility to external interference. Technical advancements are required to strengthen the security of the wireless charging infrastructure; however, these should be balanced with power loss management. This study tackles two core issues: the increasing hardware requirements for billing system authentication protocols and the interception of wireless charging signals by unauthorized users, leading to power theft and subsequent losses. To address these challenges, we propose a mechanism termed "LazyFrog". This mechanism dynamically adjusts the frequency hopping schedule, activating frequency changes only in response to detected threats during remote charging or upon identifying unauthorized access attempts. The proposed mechanism compares the expected power reception at the device with the actual power supplied by the charging station, enabling the detection of abnormal power losses. By minimizing unnecessary frequency changes and optimizing energy consumption, LazyFrog reduces hardware requirements. Moreover, we have implemented a relative distance estimation mechanism to facilitate efficient power transfer as wireless devices move within the charging environment. With these features, LazyFrog demonstrates a secure, flexible, and energy-efficient wireless charging system ready for practical application.

Solar Based Wireless Power Transmission for Electric vehicle Charging Station

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimetres to several hundred millimetres with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. For energy, environment, and many other reasons, the electrification for transportation has been carrying out for many years. In railway systems, the electric locomotives have already been well developed for many years. A train runs on a fixed track. It is easy to get electric power from a conductor rail using pantograph sliders. However, for electric vehicles (EVs), the high flexibility makes it not easy to get power in a similar way. Instead, a high power and large capacity battery pack is usually equipped as an energy storage unit to make an EV to operate for a satisfactory distance. The problem for an electric vehicle is nothing else but the electricity storage technology, which requires a battery which is the bottleneck today due to its unsatisfactory energy density, limited lifetime and high cost. Keywords: Wireless Power transfer, Electric Vehicle, Battery

A Novel Wired/Wireless Hybrid Multiport Energy Router for Dynamic EV Energy Internet With Grid-Tied and Islanded Operations

Energy routers (ERs) are indispensable in deploying energy Internet for electric vehicles (EVs), which flexibly handle the power flow regulation. Combined with the excellent characteristic of wireless power transfer (WPT) technology for non-contact energy transmission, this paper proposes a novel wired/wireless hybrid multi-port energy router (HMER) for future EV energy Internet. First, multiple bidirectional power ports are provided to control the power flow among the grid, various DC power sources, and EVs. Moreover, with grid-tied and islanded operations, the proposed HMER enables dynamic wireless energy exchange for EVs on the move. When moving along the energy exchange lane, the EVs can receive power from the HMER and conduct energy feedback, relieving mileage anxiety while creating economic benefits. Further, a mathematical model of the system is derived, and a control algorithm is introduced to perform decoupled power control for each transceiver. Finally, a SIC experimental prototype is constructed to verify the effectiveness of the proposed HMER system. Experimental results prove the transceivers can get bidirectional wireless energy interconnection on the energy exchange lane in both grid-tied mode and islanded mode, and each transceiver can realize independent power regulation.

Study on the Coil Position Adaptive Adjustment Control Scheme of Wireless Power Transfer System

Wireless power transfer (WPT) technology can completely isolate the equipment from the power supply, and has been widely used. However, the transmission efficiency of WPT system is optimal only as the transmitting coil was completely aligned with the receiving coil. But in practical applications, the mobile devices are all dynamic system, and perfectly alignment of the coils is a very demanding condition. In order to solve this problem, the paper proposed a coil position adaptive adjustment control scheme of WPT system with lateral misalignment or angular misalignment. Firstly, the relationship between transmission efficiency and lateral misalignment and angular misalignment was analyzed. And the research results show that if there is a lateral misalignment between the coils, the transmission efficiency can be optimized by adjusting the angular misalignment. Secondly, based on the hill climbing algorithm, a coil position adaptive adjustment control method was proposed. Finally, a coil position adaptive adjustment WPT system experimental platform was built, and the experimental researches are carried on. The results of the experiment show that as the transfer distance is 0.10 m and the lateral misalignment is 0.12 m, the transfer efficiency can be increased from 38.38% to 55.61% through the proposed control scheme. And the results verify the feasibility and effectiveness of control scheme proposed in the paper. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Multi-hop clustering routing protocol design based on simultaneous wireless information and power transfer technology and imperfect spectrum sensing for EH-CRSNs

Existing clustering routing protocols for multi-hop energy harvesting-cognitive radio sensor networks (EH-CRSNs) generally assume perfect spectrum sensing, which is not aligned with the practical spectrum sensing capabilities of nodes in real networks. Additionally, the severe imbalance in residual energy among cluster heads (CHs) negatively affects the successful data delivery. To resolve these problems, this paper introduces a simultaneous wireless information and power transfer (SWIPT)- and imperfect spectrum sensing-based multi-hop clustering routing protocol (ES-ISSMCRP). ES-ISSMCRP makes full use of downlink EH and intra-cluster SWIPT technologies to replenish and equalize the remaining energy among nodes, further extending network lifespan while maintaining network surveillance capabilities. Specifically, to reduce the adverse impact of imperfect spectrum sensing on network performance and improve energy utilization, this paper proposes an EH-based energy level function and associated selection criteria for CHs and relays, facilitating distributed cluster formation and multi-hop routing selection between clusters. To equalize the residual energy among nodes within a cluster, ES-ISSMCRP protocol enables cluster members (CMs) to decide whether employ SWIPT technology with a power splitting (PS) receiver architecture to transmit energy to their CH while sending data. The actual energy value transmitted by CMs using SWIPT technology is deduced by calculating the PS ratio and the expected energy expenditure of nodes for data transmission. Simulation results show that ES-ISSMCRP protocol offers significant improvements over other comparative protocols in terms of extending network lifespan and enhancing network surveillance capabilities.

Examination and experimental comparison of dc/dc buck converter topologies used in wireless electric vehicle charging applications

The studies on Wireless Power Transfer (WPT) technology and peripherals in Electric Vehicle (EV) applications are intensifying. While the energy received from the WPT system is transferred to the EV battery, the direct current (dc)/dc converter circuits are used. The dc/dc buck converter topologies are one of them. The converter circuits must be highly efficient, lightweight, and compact to have a high range in EV vehicles. There are asynchronous buck, synchronous buck, and interleaved synchronous buck converter circuit topologies from the literature. In this study, the efficiency results of these circuit topologies were analyzed using MATLAB/Simulink and experimental studies. This study contributes to the literature by conducting circuit-level efficiency analysis and component-level power loss analysis. It has been observed that the interleaved synchronous buck converter circuit operates at 99% efficiency at 1066 W. In addition, it has been shared with the oscilloscope results that the current ripples of this circuit topology are lower than other circuit converters. Specifically, there has been a significant reduction of 56% in power losses, particularly in the interleaved synchronous buck converter (ISBC). This study analyzes the dynamic behavior of the dc/dc buck converter topologies, and results about their performance are given.

Tailless Information-Energy Metasurface.

Programmable metasurface technology can achieve flexible manipulations of electromagnetic waves in real time by adjusting the surface structure and material properties and has shown extraordinary potential in many fields such as wireless communications and the Internet of Things. However, most of the programmable metasurfaces have a common feature: a tail (electrical wires and DC powers), which is difficult to supply in some particular application scenarios such as canyons and mountains. To eliminate the limitation of DC power supply, the programmable metasurface and wireless power transfer technology are combined to propose a tailless information-energy metasurface (IEMS). The tailless IEMS platform can dynamically control electromagnetic waves without relying on an external DC power supply; instead, the required DC power is provided internally by the IEMS platform itself. In the tailless IEMS experiments, the concept is demonstrated through the dynamic regulation of wireless channels and the wireless transmission of DC power. This work provides a self-powered method for programmable metasurfaces, expands the application scenarios, facilitates the miniaturization of systems, and makes it easy to integrate with other systems.

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 reconfigurable bipolar coil for wireless charging systems with interoperability and misalignment tolerance characteristics

Wireless Power Transfer (WPT) technology has been developing rapidly in recent years. Electric Vehicles (EVs), as an emerging mode of transport, also benefit from the WPT technology. Various EV manufacturers have different coupling structures, which can lead to incompatibility problems between the coils. Meanwhile, due to the human parking, misalignment between the transmitting and receiving coils may occur. To solve these problems, this paper proposes a reconfigurable bipolar coil structure with both interoperability and misalignment tolerance. A 200-W experimental prototype is built, which can achieve 84.33% and 84.76% system transmission efficiency with vertical and horizontal bipolar coils. The effectiveness of the proposed reconfigurable bipolar coil is finally verified by comparing the computational and experimental results.

A Simultaneous Wireless Information and Power Transfer-Based Multi-Hop Uneven Clustering Routing Protocol for EH-Cognitive Radio Sensor Networks

Clustering protocols and simultaneous wireless information and power transfer (SWIPT) technology can solve the issue of imbalanced energy consumption among nodes in energy harvesting-cognitive radio sensor networks (EH-CRSNs). However, dynamic energy changes caused by EH/SWIPT and dynamic spectrum availability prevent existing clustering routing protocols from fully leveraging the advantages of EH and SWIPT. Therefore, a multi-hop uneven clustering routing protocol is proposed for EH-CRSNs utilizing SWIPT technology in this paper. Specifically, an EH-based energy state function is proposed to accurately track the dynamic energy variations in nodes. Utilizing this function, dynamic spectrum availability, neighbor count, and other information are integrated to design the criteria for selecting high-quality cluster heads (CHs) and relays, thereby facilitating effective data transfer to the sink. Intra-cluster and inter-cluster SWIPT mechanisms are incorporated to allow for the immediate energy replenishment for CHs or relays with insufficient energy while transmitting data, thereby preventing data transmission failures due to energy depletion. An energy status control mechanism is introduced to avoid the energy waste caused by excessive activation of the SWIPT mechanism. Simulation results indicate that the proposed protocol markedly improves the balance of energy consumption among nodes and enhances network surveillance capabilities when compared to existing clustering routing protocols.

An Untethered Soft Crawling Robot Driven by Wireless Power Transfer Technology.

Soft robots based on flexible materials have attracted the attention due to high flexibility and great environmental adaptability. Among the common driving modes, electricity, light, and magnetism have the limitations of wiring, poor penetration capability, and sophisticated equipment, respectively. Here, an emerging wireless driving mode is proposed for the soft crawling robot based on wireless power transfer (WPT) technology. The receiving coil at the robot's tail, as an energy transfer station, receives energy from the transmitting coil and supplies the electrothermal responsiveness to drive the robot's crawling. By regulating the WPT's duration to control the friction between the robot and the ground, bidirectional crawling is realized. Furthermore, the receiving coil is also employed as a sensory organ to equip the robot with localization, ID recognition, and sensing capabilities based on electromagnetic coupling. This work provides an innovative and promising strategy for the design and integration of soft crawling robots, exhibiting great potential in the field of intelligent robots.

Modelling, simulation and hardware analysis of misalignment and compensation topologies of wireless power transfer for electric vehicle charging application

Electric vehicles (EVs) are one of the most effective means for reducing pollution and promoting sustainable transportation in developing nations. Researchers have been paying close attention to the rapid advancement of Wireless power transfer (WPT) technology because it offers a workable solution to the challenges preventing the development of EVs. EV charging uses WPT technology that transmits electricity from the source to the load (battery) using mutual induction and does not require cables or other physical connections. Power pads, misalignment, and compensation topology are technical obstacles to EV wireless charging. In this manuscript, mathematical calculations, simulations, and experimental implementation have been done for the wireless charging of EVs. Ansys Maxwell®3D and MATLAB®/Simulink software are used to simulate various parts of the system. Finite Element Analysis (FEA) using Ansys Maxwell is used to design an existing rectangular power pad. Ansys Maxwell calculates multiple parameters such as self-inductance, mutual inductance, coupling coefficient, and magnetic flux of the transmitting and receiving coils at different misalignment positions. MATLAB®/Simulink has been used to develop a series-series compensation WPT model through which the output power and efficiency of the rectangular power pad at different misalignment positions are estimated. The experimental setup uses a DC power supply, high-frequency (HF) inverter, driver circuits, compensation circuit, MSO, power pad setup, rectifier, and resistive load to verify the simulation results.

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 Power Transfer Technologies, Applications, and Future Trends: A Review

Wireless Power Transfer Technologies, Applications, and Future Trends: A Review

Cooperative Scheduling for Directional Wireless Charging With Spatial Occupation

Wireless Power Transfer (WPT) technology has been developed rapidly in recent years. The cooperative charging model and corresponding scheduling methods have been proposed to save the charging cost in paid charging service. However, the state-of-the-art methods ignore the spatial occupation issue of rechargeable devices. Moreover, the cooperative charging scheduling in directional wireless charging has not been studied yet. This paper studies the cooperative scheduling for directional wireless charging with spatial occupation. We formulate the Cooperative Charging Scheduling with Spatial occupation (CCSS) problem of Mobile Rechargeable Sensor Devices (MRSDs) for optimizing the total cost of whole charging system. We first investigate the properties of optimal arrangement of MRSDs in charging group and calculate the tight intervals of charging angles of MRSDs. We show that it is sufficient to bound the error by conducting angle discretization for only two MRSDs in each charging group. Then, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$(\ln n+1)(1+\varepsilon )$</tex-math></inline-formula> -approximation algorithm of the CCSS problem is proposed based on greedy approach, where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n$</tex-math></inline-formula> is the number of MRSDs, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\varepsilon$</tex-math></inline-formula> is the discretization error. The results of extensive simulations and field experiments demonstrate that our algorithm can reduce at most 42.5% total cost comparing with the benchmark algorithms.