Search

In the work presented in this paper, the performance of a wireless power transfer system is shown to be enhanced by means of a metamaterial slab utilized as a reflector. The metamaterial slab investigated is a 2D design consisting of a 5 × 5 array of double square split ring resonator cells. It has a near-field mu-near-zero (MNZ) and mu-negative (MNG) characteristic near the target frequency of 2.4 GHz. The array is physically compact having an area of 12.5 × 12.5 cm2. The WPT system considered in the given work is a system of two 10-turn coils separated by a distance of 20 mm. Considerable improvement in the performance is observed in terms of S-parameters and the coupling coefficient after the application of the metamaterial slab reflector. Measurements performed on the fabricated prototype validate the potentiality of the proposed metamaterial structure for improving the efficiency of a wireless power transfer system. [ABSTRACT FROM AUTHOR]

The innovations of battery and charging technologies facilitate worldwide bus electrification, which can conserve energy and reduce emissions. The emergence of wireless power transfer technology offers the potential to alleviate bus range anxiety. This paper constructs the layout models of static wireless and centralized charging stations based on the seasonal differences associated with battery capacities and passenger flow, which aims to obtain the bus charging station layout scheme of the lowest cost. Then, the heuristic algorithm is utilized to solve the layout models as the mixed linear programming problem. This study results confirm that the combined layout of static wireless and centralized charging stations is more advantageous than a single model. Finally, the required fixed cost of supporting bus system operation is explored for future capital reserves. [ABSTRACT FROM AUTHOR]

A cooperative network could improve energy efficiency by combining non-orthogonal multiple access (NOMA) with simultaneous wireless information and power transfer (SWIPT). This work proposes a novel model for optimal resource allocation for specified users through combined time switching and power splitting protocol. The system uses an amplified and forward-based energy harvesting protocol to broadcast the data in the Nakagami-m fading channel. An algorithm that provides the power coefficients for all NOMA users as a Levy Aquila optimiser is exploited to maximise the signal-to-noise ratio for far and near users. Further, the parameters of combined time switching and power splitting are brought by a game theoretic approach, which supports better energy harvesting in relay nodes with improved energy efficiency and high outage probability. The simulated results show that the employed scheme's energy efficiency has increased by 11.3%, improved from the GS-Dinkelbach algorithm. [ABSTRACT FROM AUTHOR]

To improve the irradiation profile in a conventional photocatalytic reactor, an LED-based light emitter energized by the inductive power transmission (IPT) method has been proposed recently. However, technical challenges such as low coupling due to the asymmetrical wireless coupler, dynamic impedance due to multiple receivers and changing magnetic properties in the transmitter core, and ease in upscaling remain to be addressed. This work proposes an IPT system for an LED-based photocatalytic reactor using a toroidal transformer to match the impedance between a modified Helmholtz transmitter coil and a class-E inverter. A finite element magnetic field simulation and analytical calculation of the induced voltage are used to assess the field uniformity inside the coil. The mutual inductance at selected locations within the coil volume and the power transfer efficiency (PTE) are evaluated. The proposed system requires less than 2 W to generate a uniform magnetic field inside a 10.6 L acrylic cylinder with an induced voltage of 13.9 ± 0.95 Vrms along the cylinder's central axis. The proposed wireless coupler achieves a coupling coefficient of 0.013–0.034 and a PTE of 23.7%, outperforming similar systems with asymmetrical coupler design while offering a versatile solution for integrating IPT technology into wastewater treatment. [ABSTRACT FROM AUTHOR]

Aiming at the problem of unstable output voltage and rapid reduction of efficiency caused by coil misalignment in the wireless charging process of wireless chargers, a hybrid wireless power system with anti-misalignment and constant current (CC) output characteristics is proposed. The system uses a high-order compensation network and a four-coil bipolar (BP) coupler to implement high anti-misalignment and CC output characteristic that is decoupled from the load. By inserting a high-order compensation network, the two overlapping coils in the same side of the transmitter and receiver sides of the BP coupler can be effectively decoupled and the design methodology can be simplified. Moreover, by adjusting the inductance value of the transmitter compensation network, the BP coupler can be made available for the occasions with different equivalent mutual inductance (MI) fluctuation requirements. While the receiver coil is suddenly removed, the system has a self-protection function, which can effectively limit the current flowing through the inverter. The design ideas of the coupler and compensation network are also discussed in this paper. Ultimately, a 1-kW experimental prototype is built to validate the proposed scheme. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) has been developed as a suitable candidate for energy transfer in various applications, recently. Resonant tank is the main passive part of such systems and various topologies are introduced to improve WPT systems performance. Characteristics of these topologies definitely affect system overall performance. Therefore, each topology's specification and performance indexes should be evaluated and compared to choose a suitable one for a required application. In this paper, the characteristics and behaviour of voltage gain, input admittance and efficiency of well-known compensation topologies are thoroughly investigated for the first time. By calculating the voltage gain sensitivity, some analysis are performed on typical compensation including SS, SP, LCL-S, LCL-P, LCC-S, LCC-P and double-sided LCC under key parameter variations such as load resistance, switching frequency and coupling coefficient. In addition, by introducing a new formula for efficiency, the effect of resonant tank elements on efficiency is studied analytically which has not been performed before. In order to evaluate the theoretical analysis, the performance of all compensation topologies is investigated in MATLAB environment. By employing prototype SS and SP compensated inductive power transfer (IPT) test-bed system, some experimental verification are performed and the results confirm the analytical and numerical simulation findings. [ABSTRACT FROM AUTHOR]

This article reviews various inductive and capacitive wireless charging systems to achieve high-power infrastructures. The characteristics of SAE, ICINRP, and IEEE safety standards for wireless charging technology were highlighted. The working of compensation circuits, resonant converters, and challenges in wireless power transfer (WPT) systems was discussed. The mechanism of different compensation circuits used in the WPT was discussed in detail. In addition, the design of the converter circuit topology of inductive and capacitive power transfer systems in electric vehicle (EV) batteries was highlighted. The foreign object detection (FOD) methods that prevent output power variations due to metal/living objects in the charging environment were explored. The foreign object detection (FOD) techniques in terms of impedance variations in the primary side of the charging circuit were explained. This review on EVs would help researchers and industrialists to identify and develop novel charging infrastructure with low cost and charging time. [ABSTRACT FROM AUTHOR]

The charging coil plays an important role in the wireless charging system system. However, there are still some problems in the design of the wireless charging coil, such as the low coupling coefficient. In order to improve the coupling effect, this paper proposes an optimized design scheme for the metal shielding layer structure of DD coil. Firstly, the influence of the structure size of DD coil metal plate on the coupling coefficient is studied by the mathematical modeling analysis. Futhermore, the maxwell simulation is used to study the metal plate coupling coefficients with varying structure sizes, addressing receiving uniformity issues. The optimal size of the shielding layer is designed for optimal magnetic coupling in wireless charging. Finally, this paper validates the feasibility of the improved metal shielding layer through experiments. The research in this paper may have a reference role in the wireless charging system of electric vehicles. [ABSTRACT FROM AUTHOR]

In this article, a wireless power transfer (WPT) system with a single transmitter to power multiple electronic loads simultaneously using multiple receivers is proposed. We analyzed various types of coil geometries on the receiver side, including circular, square, hexagonal and octagonal shapes. Then, employing the finite element analysis (FEA) method with the ANSYS MAXWELL simulation tool, we identified the most efficient coil design system based on parameters, such as self-inductance, mutual inductance and coefficient of coupling factor. Subsequently, the electrical parameters necessary for the proposed concept were calculated from the equivalent circuit model and simulation of the proposed model was performed using the LT-Spice simulation tool. An 85 kHz resonant frequency was achieved using a high-frequency inverter (HFI), and inductor-capacitor-capacitor (LCC) compensation topologies were employed to provide different power capabilities to the loads. [ABSTRACT FROM AUTHOR]

The performance of the simultaneous wireless information and power transfer (SWIPT) enabled full-duplex (FD) relaying in non-orthogonal multiple access (NOMA) networks is investigated in both reliability and security aspects. More precisely, for the viewpoint of reliability, we derive in the closed-form expression the outage probability (OP) at both end-users. On the other hand, intercept probability (IP) is considered a helpful metric to measure the security of the considered systems. Moreover, we derive the IP in the closed-form expression too. Numerical results are also given to confirm the correctness of the derived mathematical framework as well as to identify the insights of both metrics as a function of some key parameters such as the transmit power, the power-splitting (PS) ratio, and the power allocation ratio. [ABSTRACT FROM AUTHOR]

The effects of Electromagnetic Interference (EMI) in Inductive Power Transfer (IPT) for electric vehicle charging circuits are elaborated with Common Mode (CM) emission. Electromagnetic Compatibility (EMC) has to be sustained in the circuits such that it is prone to the effects of interferences, noises and disturbances. These issues can be addressed at the initial product development stage, with accurate identification of the parameters that influence the CM emission in the circuit. The analysis of EMI focuses on three features, namely Source of EMI, Coupling path and Receptor. In the IPT model, the primary source of the EMI is the power converter used for high-frequency supply to the inductive coils. The power converter switches and the heat sink with its Printed Circuit Board (PCB) design are predominant in power electronic circuits. This paper facilitates the reduction of EMI without including complex filters. The system is tested for the violated standard SAEJ2954. In addition, the article corroborates precognitive modeling by implementing compensation networks used in IPT applications and their effectiveness in reducing the leakage current caused by the converters and the coils. The paper insights the air gap variation of the coil with the power transfer efficiency and its influence on electromagnetic interferences. The Fast Fourier Transform (FFT) analysis used in PSIM shows leakage current and harmonic reduction with the compensation network and Pulse Width Modulation (PWM) technique. The fabrication model for the front end power supply to the IPT is tested. The electrical noise emission is estimated using predictive modeling. [ABSTRACT FROM AUTHOR]

In this letter, we establish physical-layer security based on frequency diverse array (FDA) together with directional modulation (DM) for decode and forward (DF) relaying simultaneous wireless information and power transfer (SWIPT) system. The analytical expressions of the ergodic system secrecy capacity under the time switching (TS) protocol are derived. Moreover, the impacts of system parameters on secure performance are analysed. Numerical results reveal that the proposed method achieves better security performance than conventional PA solutions, especially in the range dimension. [ABSTRACT FROM AUTHOR]

Class-E inverters used in wireless power transmission systems must be load compatible to ensure efficient and safe wireless power transmission. There are two different ways to match loads. The first can be supplied by varying the source voltage, and the second may be supplied by adjusting the capacitance in the resonant circuit. In the literature, the second strategy is the most well-liked and effective one. The distance between the coils in a wireless power transmission system affects the inverter load value. In this study, load compatibility in a wireless power transmission system using an E-class inverter is performed using a capacity array. For this purpose, an adaptive neuro fuzzy (ANFIS) model, in which the voltage and current values of the system is used as input, has been designed to determine the most appropriate capacity and to ensure load compatibility. The results of the simulation and experimental studies have shown that the load compatibility of the Class-E inverter can be achieved with precision when changes in the distance between the transceiver coils are taken into account. [ABSTRACT FROM AUTHOR]

For meeting the actual demand of constant current (CC) and constant voltage (CV) in lithium-ion battery-charging process and improve the flexibility and safety of charging, this paper proposes a family of hybrid inductive power transfer (IPT) topologies that can realise CC and CV output and are not limited by the parameters of coils. Starting from a single existing topology with configurable CC or CV output, which can achieve zero-voltage switching (ZVS), load-independent and approximately zero reactive power, and the missing configurable CC or CV output is obtained by circuit transformation through cascaded T-type network. Then, the cascaded T-type network is switched by mode switches, so as to derive a family of hybrid IPT topologies suitable for lithium-ion battery wireless charging. In order to reduce the number of devices in the compensation network, the T-type network can be integrated with the existing compensation networks. Hence, this paper also proposes some hybrid IPT battery chargers and their design ideas. The control logic of mode switches and the sensitivity of compensation parameters are also discussed. Ultimately, a hybrid IPT battery charger based on S-S and S-LCC compensation networks is developed to test the correctness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper presents a detailed review of the design aspects and performance analysis of high-frequency inverters used in inductive power transfer application (IPT) for electric vehicles. The paper's main scope is focused on the design of inverters used explicitly for wireless charging with misalignment variations and coil dimensions. The research articles in the literature focus on the high-power transfer and coil structures for the existing topologies. The magnetic resonance coupling in the IPT system depends on the resonance phenomenon. The operating frequency of the inverter must be the same as the resonant frequency in the compensation network. On complete assessments, the paper emphases on suitable inverter specifications for wireless charging and its related issues. In addition, the resonant inverters can be replaced with H-bridge inverters in consideration of voltage stress and harmonic control. Investigations on harmonic elimination strategies for H-bridge and resonant inverters are also discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, we consider a power splitting (PS)-based simultaneous wireless information and power transfer (SWIPT) system, which is having I and Q (in-phase and quadrature) imbalance hardware impairment. The prime objective of this paper is to maximize the harvested energy for a SWIPT PS system, satisfying a minimum signal to noise ratio (SNR) requirement for information signal processing in the presence of IQ imbalance hardware impairment. The paper uses four types of bio-inspired algorithms like Particle Swarm Optimisation, Artificial Bee Colony, Firefly Algorithm and Invasive Weed Optimisation to attain the maximum harvested energy considering parameters of PS ratio, amplitude and phase imbalances in a Rayleigh fading environment. The simulation results show that under ideal power conversion efficiency and minimum hardware impairments, a maximum SNR of 16.7 dB and harvested energy of 11 dB is achieved for a transmit power of 20 dB in SWIPT systems for IWO bio-inspired algorithms in the 32 QAM modulation scheme. [ABSTRACT FROM AUTHOR]

In this paper, we present a design method for a highly efficient retrodirective array (RDA)-based microwave power transfer (MPT) system for the mMTC scenario, and evaluate its characteristics through experiments. Long-range wireless power transfer is required to effectively support the mMTC situation. RDA-based MPT controls and tracks the power beam towards the device within a certain range and it enables efficient power transfer. The overall link budget analysis is examined first and the required antenna gain is calculated. The required antenna gain can be secured using multiple-antenna modules. So, it is possible to design an RDA-based MPT system. In this paper, we implement a reduced RDA-based MPT system and evaluate its characteristics to confirm the feasibility of this design method. Through experiments, it has been confirmed that additional gain can be secured by using multiple antenna modules, and the RDA function can be effectively operated to effectively make a power beam in the direction of the power receiver. Conclusively, the gain of about 2.2dB increased whenever the number of antennas is doubled. The experimental results also show that the RDA-based MPT system designed in this paper is capable of adaptive power beamforming from −30 degrees to 30 degrees. [ABSTRACT FROM AUTHOR]

Many novel devices such as induction cookers or wireless power transfer produce electromagnetic fields (EMFs) in the intermediate frequency (IF) range (300 Hz to 10 MHz) and it is very meaningful for summarizing the bioeffects of IF-EMF research, particularly animal studies. This review takes into account experimental studies that used murine models to study the health effects of exposure to IF-EMF. The analyses included here use data available in the literature published from January 1988 to August 2021 including the animal studies about general adverse effects, tumorigenic effects, and effects on developmental stages. The studies that linked IF-EMF exposure during pregnancy or neonatal stage to behavioral and cognition changes were included. Additionally, this review also covers the effects of IF-EMF on gene expression patterns in the brain, behavior patterns associated with learning and memory, and immune function. Although most studies have suggested that IF-EMF is harmless, some adverse effects have been reported after exposure at developmental stages and prolonged exposure. Compared to extremely low frequency (ELF) or radiofrequency (RF) EMF bands, studies on health effects with more diverse perspectives of IF-EMF have not been conducted. Therefore, performing more research should be necessary using the latest biomedical tools. From this point of view, a comprehensive review of IF-EMF studies, particularly animal studies, will provide a valuable basis for further risk analysis in humans. [ABSTRACT FROM AUTHOR]

In the existing pieces of literature about the three-coil wireless power transfer (WPT) system, a three-coil structure is proposed to increase the efficiency compared to the two-coil WPT system. The cross-coupling among three coils, compensation capacitor of the repeating coil (RPC) and the rectified load are considered incompletely. The circuit model of a three-coil WPT system with rectified load is developed by taking the cross-coupling of all coils and the compensation capacitor of RPC into consideration in this paper. The relationship among system efficiency, compensation level, and rectifier load is deduced. The detailed mathematical analysis and compensation capacitor selection of RPC are investigated to improve the system efficiency. An experimental study demonstrates that the selected compensation capacitor of RPC achieves a higher efficiency than resonant compensation in a three-coil WPT system with different cross-coupling conditions and rectifier load conditions. System efficiency is promoted from 73.9% (resonant compensation capacitor for RPC) to 84.2% (selected compensation capacitor for RPC). [ABSTRACT FROM AUTHOR]

To reduce the pollution to a large extent in the transportation sector, it is important to charge the Electrical Vehicles (EV) from sustainable sources of electricity, such as solar or wind energy. Building integrated photovoltaic (BIPV) systems have gained popularity over the past 10 years and have been demonstrated to be a practical method of generating renewable energy that can be used to partially power buildings. One of the emerging technologies in EV charging systems is wireless charging technology; we realize that using this technology, fully automatic charging is simple. Compared to a plug-in charging system, wireless charging is free from rust, rain, and other environmental impacts like vandalization and visual pollution. By integrating wireless EV charging with BIPV shading systems, it offers a green and cutting-edge charging option. Building integrated solar panels are affected by different scenarios and causes due to their positioning. The direction of the solar panel, tilted position, and reflected irradiation, these all factors are to be considered in design of BIPV system. In this article, a system designed in way to analyze the effect of white and black color reflectors effect on solar panels (shading system) in different directions. In this work, a 256-W wireless charging system developed for E-bikes utilizing BIPV system. The proposed BIPV-fed resonant inductive charging system achieved efficiency of 95% for simulation and 91.6 for experimental analysis. The experimental analysis is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are well-known as environmentally friendly systems. Therefore, the demand for EVs is rapidly increasing every day, but for charging batteries of EVs eco-friendly electrical energy sources are needed. To use a clean energy source, this article proposes a wireless power transfer (WPT) system energized by photovoltaic panels. In this study, pulse density modulation technique controlled with incremental conductance algorithm is preferred in the WPT system for both transferring power from primary to secondary windings and for tracking maximum power point (MPP). The proposed system was tested with an experimental prototype and the results were presented. As a result, both 99.22% MPPT efficiency was obtained and power was transferred from primary to secondary with 90% efficiency. [ABSTRACT FROM AUTHOR]

In this work, the secondary side controlled wireless power transfer (WPT) converter using a LC/S compensation topology is proposed. The constant voltage charging control mode of the proposed converter is evaluated based on high efficiency. In the secondary side, a semi-bridgeless active rectifier (SBAR) is used for the output voltage regulation. In order to improve the efficiency performance of the converter, the pulse density modulation (PDM) control method is applied to the switches of the SBAR. The primary switches operate at the constant operation frequency as independent of the secondary side. There is no communication needed between primary and secondary sides of the proposed converter. Besides, the switches of the SBAR operate with soft switching. The basic principles of the LC/S compensation network and SBAR topology are presented with steady state analysis. The PDM control strategy applied to the switches of the SBAR is discussed. In order to validate the performance of the proposed converter, a prototype is built with 8 cm air gap coreless coupling coils. The input voltage of the converter is 30 V, and its maximum output power is 60 W. The maximum efficiency is achieved as 85.26% at full load condition during CV regulation. [ABSTRACT FROM AUTHOR]

In the modern communication era, antenna arrays play a vital role, demanding more constrained antenna arrays with high gain, ultra-low sidelobes, and other characteristics. The introduction of the fourth dimension, time in antenna arrays, reduces the effort needed for synthesis and offers flexibility in designing high-performance antenna arrays. The fourth-dimensional antenna with time as the fourth dimension is also known as Time-Modulated Antenna Array (TMAA). The modulation of the antenna array by periodic time sequence generates harmonic radiation patterns. This paper represents a review of TMAA from its evolution to the current progress. The virtue of time modulation provides multi-beam radiation from TMAA, which finds its application in numerous fields like secure communication, tracking of elements, and simultaneous scanning in azimuthal and elevation planes. The exploitation of TMAA in the fields requires synthesis of the radiation pattern, making it suitable for the application by reducing the sidelobe and sideband levels, radiating sum-difference patterns, multi-tone radiation, Wireless Power Transfer, antenna failure correction, and many more. Furthermore, TMAA with an optimized timing sequence may find a place in future generations' communication. [ABSTRACT FROM AUTHOR]

The dual-credit policy for auto manufacturers and the subsidy policy for charging infrastructure operators have become important policies to guide and promote the development of the automotive industry. However, few studies consider the impact of mixed policies on the market strategies of auto manufacturers and charging infrastructure operators considering consumer green preferences. To fill the gap, this article establishes optimization models to analyze and compare the effects of mixed policies on the decisionmaking of auto manufacturers and charging infrastructure operators under the cooperative and noncooperative modes considering consumer preference. The results reveal four main insights: (1) Two types of policies all have direct positive effects on the market diffusion of electric vehicles. Under the noncooperative mode, the dual-credit policy has no spillover effect. Under cooperative mode, two types of policies all have spillover effects. The dualcredit policy and charging infrastructure subsidy policy have positive superposition effects on the optimal number of charging piles, and the optimal demands for electric vehicles. (2) When the credit price is less than a certain threshold, there is a substitutive effect between the charging infrastructure subsidy policy and the dual-credit policy on promoting the market diffusion of electric vehicles. (3) There is a substitutive effect between high-level consumers' green preference and policies on promoting the market diffusion of electric vehicles. (4) Under the cooperative mode, the direct and spillover effects of policies are more than that are under the noncooperative mode. These insights demonstrate the effectiveness and limitations of policies and the importance of providing complementary policies for consumers. The government should encourage market cooperation between auto manufacturers and charging infrastructure operators, maintain a stable price level for credits, and introduce incentive policies for green consumption. [ABSTRACT FROM AUTHOR]

It is important to analytically and accurately calculate the self-inductance of the primary and secondary coils and the mutual inductance between them, in order for the optimization algorithm of the Inductive Power Transmission (IPT) system. In this paper, the inductance calculation methods used in the IPT designs at different power levels are examined. The performances of these methods have been evaluated according to the experimental results of these IPTs using rectangular coil pairs. Inductance results were obtained with Finite Element Analysis (FEA) for IPTs without experimental results. Accordingly, a 120 W IPT has been designed to be used for wireless charging of the Electric bicycle (e-bike). Rectangular spiral coil pair with 75 mm distance between them was fabricated according to the design result. Analytical and experimental inductance values are compatible with each other for the optimal IPT design. The efficiency between the DC power supply to the load has been achieved as 92.1672% in approximate load conditions. [ABSTRACT FROM AUTHOR]

Two-coil wireless power transfer systems are composed of two circuits tuned at the same resonance frequency, one containing the source and the other containing the load, where both are connected to each other by a mutual inductance. The power delivered to the load circuit is divided by the total power supplied by the source or, alternatively, by the maximum ideal amount of power that can be delivered to the load circuit, are usual figures of merit known as efficiency and power transfer capability, respectively. Additionally, a third figure of merit can be defined as the power dissipated at the source circuit divided by total power supplied by the source. It has recently been demonstrated that efficiency and power transfer capability are related to this recently defined third figure of merit. In this paper, a simple method is presented to monitor the power dissipated at the source circuit divided by total power supplied by the source, which allows a determination of the efficiency and/or power transfer capability without a direct measurement at the load circuit. The advantages and limitations of the proposed method are discussed in detail. Practical results are included to verify the proposal. [ABSTRACT FROM AUTHOR]

Pacemakers have existed for years for patients with heart failure to re-establish cardiac electrical pulses. However, the main complication related to a traditional pacemaker is its limited battery life. To circumvent such problems, wireless battery charging technology is one of the emergent applications for cardiac pacing. In this paper, an implantable rectenna, consisting of a circularly polarized (CP) monopole antenna, matching circuit and a rectifier, is proposed for pacemaker battery charging. To reduce the impedance mismatch loss, the matching network is incorporated between the antenna and the rectifier. A pair of T-shaped slots are introduced in the ground plane of the antenna to achieve the desired CP operation. The resonant frequency of the rectenna is 2.45 GHz with an impedance bandwidth of 28.45% and 5.73% 3 dB AR bandwidth. At −10 dBm input power, the rectenna output is 0.3 V with a rectenna efficiency of 41%. [ABSTRACT FROM AUTHOR]

The microwave wireless power transmission system avoids the problems of large consumables, complex construction, and high maintenance costs caused by the cable. It can be seen that this method has specific demands and is worthy of deep research. This paper designs a high-power dual-frequency rectifier circuit that works at 1.15 and 1.7 GHz for wireless energy transmission. Using GaN HEMT as the rectifier, the output DC power reaches 6.5W, far beyond the conventional diode rectifier circuit in terms of power capacity. [ABSTRACT FROM AUTHOR]

In this work, implementation of constant current (CC) and constant voltage (CV) control of the LC/S compensated wireless charging converter (WCC) is presented. The LC/S compensation topology, operating as load independent in CC mode, is used in the proposed WCC. The CC charging control mode of the WCC is achieved at the constant operation frequency providing the maximum power transfer. On the other hand, frequency modulation (FM) control method is applied to achieve the CV charging control operation. Thus, implementation of entire charge period of WCC using LC/S compensation is provided with a minimum frequency variation. The basic principles and the analytical analysis of the proposed WCC are presented. The analytical output regulation, during CC and CV charging control modes, is discussed based on power transfer efficiency. Finally, a prototype with 60 W output power is built to validate the presented analytical analysis. The efficiency variations of CC and CV charging control modes are extracted as function of the load condition. The misalignment performance of the proposed system is also evaluated based on the load condition. The maximum efficiency of the proposed system is measured as 86.6% at 70 mm air gap and 40 W output power. [ABSTRACT FROM AUTHOR]

Microwave power transmission (MPT) has many advantages. However, previous studies have indicated that MPT interferes with wireless data communication. In this paper, an adaptive polarization switchable rectenna architecture is proposed for simultaneous wireless information and power transfer. When the rectenna is activated by a wireless energy transmitter, the antenna automatically switches to another quadrature polarization state for wireless data communication. The experimental results show that the adaptive switching characteristic provides a wireless channel isolation of more than 23 dB between wireless power transfer and data communication. In a practical indoor environment, the measurement of packet error rate of the communication link shows that the power level of MPT could be increased by 16 dB and still keep the wireless connectivity. Thus, the proposed design is suitable for devices powered by MPT and for simultaneous wireless information and power transfer applications. [ABSTRACT FROM AUTHOR]

This paper presses a smart charging decision-making criterion that significantly contributes in enhancing the scheduling of the electric vehicles (EVs) during the charging process. The proposed criterion aims to optimize the charging time, select the charging methodology either DC constant current constant voltage (DC-CCCV) or DC multi-stage constant currents (DC-MSCC), maximize the charging capacity as well as minimize the queuing delay per EV, especially during peak hours. The decision-making algorithms have been developed by utilizing metaheuristic algorithms including the Genetic Algorithm (GA) and Water Cycle Optimization Algorithm (WCOA). The utility of the proposed models has been investigated while considering the Mixed Integer Linear Programming (MILP) as a benchmark. Furthermore, the proposed models are seeded using the Monte Carlo simulation technique by estimating the EVs arriving density to the EVS across the day. WCOA has shown an overall reduction of 13% and 8.5% in the total charging time while referring to MILP and GA respectively. [ABSTRACT FROM AUTHOR]

Traditional flat wireless power transmission is charging in a "one-to-one" manner. When the rotation angle of the receiving and transmitting coils is offset, their mutual inductance M and coupling coefficient will decrease. Multi-freedom motor is used in bionics, it is necessary to supply power to the visual acquisition device inside the rotor when rotating, and it is more convenient to use wireless charging instead of wired charging. A receiving structure suitable for moving devices is proposed, which can effectively improve the power transmission efficiency (PTE) when the angle is shifted. In the wireless power transmission, the mutual inductance M and coupling coefficient of the transmitting coil and the single-coil structure, the three-coil structure and its single coil in the rotation are calculated. The advantages and disadvantages of each structure are analyzed. Finally, experiments verify the accuracy and validity of the theory. [ABSTRACT FROM AUTHOR]

Different wireless power transfer (WPT) technologies using inductive, capacitive, or optical coupling, and microwaves have been theoretically investigated and many have been employed in commercial products. WPT technologies have their own advantages and drawbacks and have been individually studied. This article envisions a concept of universal and ubiquitous wireless power transfer (U2WPT), in which power can be wirelessly transferred between any entity, whether stationary or in-motion, as long as they are equipped with appropriate energy transmitters and receivers. The realisation of such a U2WPT concept allows for the analysis of the sustainability of existing WPT systems in a unified manner, and to potentially overcome their limitations and engender greater energy mobility, flexibility, and sustainability. In addition, market mechanisms for U2WPT systems are introduced, along with an analysis of the benefits engendered in terms of economic, environmental, human and social outcomes, and improvement of energy and transportation systems. Finally, a discussion on the realisation of the U2WPT concept including policy implications, and recommendations for future research directions essential to their deployment is presented. [ABSTRACT FROM AUTHOR]

With the evolving demand for sustainable mobility, adequate charging infrastructure for electric vehicles (EVs) has been growing steadily and wireless power transfer (WPT) technology has been seen as an efficient alternative for EV charging while maintaining seamless traffic flow. This paper reviews the modelling challenges in terms of both static (plug-in) charging (SC) and wireless charging (WC) facilities in a transportation network in terms of system integration, focusing on the evolution of the WPT technology. The first part of the paper provides an overview of all the major progress and achievements made by different research organisations in the area of WPT technology for EV charging. These technologies are ranked based on two indices, namely technological readiness level and system readiness level. The optimal location of WC facilities comes with more design and operational issues than conventional static charging facilities. However, they are similar in terms of the infrastructure modelling approach to locate these charging facilities, as the overall goal is to maximise the network flow and minimise the overall system cost. The second part of the paper assesses different modelling approaches used to analyse the network and locate the charging infrastructure for static and WC facilities. The economic feasibility of the technology is an important consideration for successful system integration as well as the overall performance of the system. As such, this paper also provides a synopsis of different socio-economic studies related to the WC infrastructure allocation problem. Finally, future research directions in this field are discussed based on the knowledge gaps identified from the existing literature. [ABSTRACT FROM AUTHOR]

This article investigates the tracking control of the wireless power transfer (WPT) system with disturbances and constraints. Using the generalized state-space averaging method, a small signal perturbation model of the system is obtained. To estimate the perturbation faster and more accurately, the fixed-time disturbance observer is introduced. Then a fixed-time disturbance observer-based controller (DOBC) is designed. In addition, to ensure the WPT current constraint not be violated, tan type Barrier Lyapunov Functions (BLFs) are added. To illustrate the robustness of the WPT system, a 100-watt WPT system is built and the closed system is proved to be effective. Experimental results show that the startup response time of the current is 4 ms without overshoot. Under loads and resonance capacitors changes, the WPT current can also converge to the reference value within 4 ms. [ABSTRACT FROM AUTHOR]

The efficiency of a multiphase wireless power transfer (WPT) system varies with the size and position of loads. Based on the traditional WPT system, the efficiency improvement of three-phase WPT system under load variation was studied. A three–phase shift control (PSC) strategy is proposed. Mathematical formula of optimal resistance is deduced and the optimal phase shift angles (PSA) for maximum efficiency are presented in the three-phase WPT system. Through the analysis of the electromagnetic model of the system, the optimal phase angle at which the load maintains optimum efficiency at different locations is deriving. A three-phase WPT phase experimental platform based on PSC is built. Verify the validity and correctness of PSC strategy. Simulation and experimental results show that the efficiency of the receiving coil can be increased by 10−15% after the phase is adjusted at different positions. The proposed three-phase phase shift control strategy has a guiding and reference significance for subsequent related research. [ABSTRACT FROM AUTHOR]

In this article, we report the test strategy and the results obtained from measurements of a CMOS integrated power amplifier. The power amplifier was designed to optimally-drive an inductive link used in wireless power transfer. As part of the proposed strategy, we designed an integrated oscillator to generate the carrier frequency, as well as dc and ac envelope detectors to estimate the output power and the backscatter response. A printed board based on a microcontroller was designed to implement several test functions in a compact way. The oscillator frequency and the power delivered to the resonant load can be digitally controlled, giving flexibility to the system. Using all the designed circuits we measured the performance of the power amplifier, that achieved a maximum output power of 24.2 dBm with 48.1% efficiency at the 986 MHz frequency. [ABSTRACT FROM AUTHOR]

In order to increase the energy transmission density between the coupled coils in the wireless power transmission (WPT) system, this paper propose the push–pull magnetic field excitation. A push–pull (PP) system that can enhance the energy transmission density is proposed by using the superimposed field effect of two transmitting coils from two different directions on the receiving coil in this paper. Firstly, the power and efficiency formulas of the system transmission are theoretically deduced. Then, the PP system is designed and constructed. The analysis shows that the transmission power will change with various superposition effects of electromagnetic waves. After, we use MAXWELL simulation software to simulate the magnetic field intensity distribution of the PP system, and set up a 100 W PP system experimental platform. Comparing the same direction and reverse direction of the PP system with the system performance parameters of the traditional WPT system, the effects of different resonant circumstances of two transmitters on the energy transmission density of the system are discussed. Experimental results show that the power capacity of the PP–WPT system is 55.5% higher than that of the conventional WPT system. It provides new ideas for the research and application of subsequent WPT. [ABSTRACT FROM AUTHOR]

The rectenna as a device, is critical for achieving long-distance wireless power transfer. The centrality of this study is focused on adding to the collective knowledge of the subject matter, by providing a new perspective in terms of an alternative design for the antenna component of the rectenna. Essentially, this study features a novel "3-point star" design which was simulated in comparison with the conventional square microstrip patch antenna design. Both designs (i.e., operating at the Wi-Fi band 2.4 GHz), were assessed in terms of simulated performance parameters: gain, directivity, return loss, radiation pattern, and efficiency. From the simulation results, the proposed "3-point star" design, though slightly less efficient exhibited improved performance over the conventional square patch alternative, in terms of gain, directivity, and return loss. For the rectifying component, a greinacher voltage-doubler (with two HSMS2820 diodes), was designed separately and simulated over a range of input power levels (10dBm—34dBm), for 220-Ω, 380-Ω and 810-Ω load resistances, respectively. A maximum conversion efficiency of 88.02% was achieved at 28dBm for an 810 Ω load resistance. All design simulations were executed using Advanced Design System (ADS) software. [ABSTRACT FROM AUTHOR]

.Wireless communication technologies have advanced from cellular networks to satellite systems which create an advancing demand for low power battery operated decoding unit. Widely used error correction technique in the wireless communication systems is the channel coding. In channel coding, convolutional codes are commonly used for the transmission of data over a noisy channel. The methodologies adopted in the proposed design to achieve low power and increase in performance is by designing the architecture of the Viterbi decoder at circuit level design using a sleepy keeper technique, which curtails the leakage power dissipation. The second method is by including the modified register exchange algorithm, which reduces the occurrence of error probability with low power in signal transmission in the wireless domain. Simulation of the design is executed in 45nm TSMC in Tanner-SPICE. Promising results are obtained with reduction in power 31.54% with the CMOS technology for the WLAN frequency of 2.5MHz. BER performance of the design also found to be low in the channel environment. [ABSTRACT FROM AUTHOR]

In this paper, we present a rigorous optimization method to design a wireless power transmission (WPT) system. In order to enhance the power received by the receiver, parasitic components are integrated into the system. Our analysis shows that a system with square parasitic wire actually gives better performance than its circular counterpart. From our results, it can be seen that the presence of square parasitic wires in the system improves considerably the efficiencies, as well as the distance of effective power transfer. By implementing two square parasitic wires and using an optimization algorithm to carefully select the positions of the receiving antennas, we show that power coupled to one receiver can be significantly enhanced; while the other suppressed – the peak power at the receiving antenna is improved to 15.7% and the power detected by the adjacent antenna is minimized to as low as 2.6%. This result is important as it shows that the parasitic components do not only enhance the power coupled to the receiving antenna, it also effectively reduces crosstalk in adjacent antennas. Indeed, it can be observed that the peak efficiency obtained using two parasitic wires (with the transmitter sandwiched in between the two wires) is almost twice of that using a single wire. [ABSTRACT FROM AUTHOR]

The design of transmitting antenna arrays with a modular aperiodic architecture for far-field wireless power transmission (WPT) is addressed in this work. The synthesis of the subarray layout and of the subarrays weights is carried out to maximize the power transmission efficiency, while guaranteeing the full aperture coverage with simple domino-shaped tiles. Two design methodologies, one enumerative and one optimization-based, customized to the synthesis of small and larger apertures are presented. The best tiled array configuration is obtained through the maximization of the beam collection efficiency (BCE) for a given collection area where the receiving rectenna system is assumed. A set of representative numerical examples, including both ideal and real antenna models, is shown to prove the effectiveness of the proposed architectural solution as well as of the clustering methods. Analyses considering different array dimensions and sizes of the collection area, when scanning the beam off-boresight also along diagonal directions, are given to assess the performance of the proposed solutions. [ABSTRACT FROM AUTHOR]

This paper investigates the solution to an optimisation problem to minimise the total transmission power at the transmitter in a cooperative non-orthogonal multiple access (NOMA) system with simultaneous wireless information and power transfer (SWIPT) and an energy-harvesting user. First, we formulate the optimisation problem to obtain the minimum transmission power at the transmitter under the constraints of minimum signal-to-interference-plus-noise ratio and minimum energy harvesting. Since the problem is not convex, we transform it into a bi-level optimisation problem. Then, conditions to guarantee the feasibility of the problem are provided, and we derive the analytical optimal solution via the Lagrange method meeting Karush–Kuhn–Tucker optimality conditions to solve the lower-level variables of the inner convex problem. Second, we use particle swarm optimisation to find the approximately optimal values of the upper-level variables. Next, we present two baseline schemes based on orthogonal multiple access (OMA) and equal power splitting for performance comparison with the proposed cooperative NOMA system with SWIPT. Finally, simulation results show that cooperative NOMA with SWIPT can reduce the transmit power at the transmitter, compared to two baseline schemes: OMA and EPS. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) technologies have now reached a commercial stage in applications going from consumer electronics, biomedical implants and domestic applications. For electrical cars, WPT offers some new opportunities compared to classical wired charging. Although there exist some commercial cars equipped with wireless charging system, improving design procedures needs to address various domains including power electronics, components and electromagnetics. The magnetic coupling system is a key component of wireless power transfer: the coils and surrounding materials have a great impact on the efficiency of the transfer as well as the level of the stray field near the system. The paper aims to present three essential features regarding the inductive power transfer dedicated to electric vehicles. The first one addresses the topology and efficiency of the coupling system, the second one underlines the human exposure considerations and the third one deals with the impact of uncertainties regarding system parameters. [ABSTRACT FROM AUTHOR]

In wireless charging system, limited by the coupling effect between the loads and the change of the equivalent impedance of the battery, it becomes difficult to provide efficient and stable energy supply for multiple load devices. In this paper, a multi-load constant current charging technology for wireless charging system is proposed, which combines the primary side control and the secondary side control to achieve quick charge for multiple load batteries at the same time. The system reduces the influence of interference factors by designing the primary side control module and the transmission structure, to ensure sufficient and stable transmission of energy. And utilising the secondary side control module to charge the battery with constant current, which increases the charging speed, and reduces the impact of battery impedance changes on the system's transmission state. It is verified by experiments that when charging four 1.2 V Ni-MH batteries, the receiver at different positions within the coverage of the transmitting coil can achieve 100mA constant current charging for the battery and the output voltage fluctuation range of each receiver is within 0.2 V, and the working efficiency of the system can reach 70%. [ABSTRACT FROM AUTHOR]

During the dynamic wireless charging of electric vehicles, the offset from the vehicle Rx coil will reduce the mutual inductance of the coupling mechanism, which results in a significant reduction on the transmission efficiency of the system. Now a real-time detection method of electric vehicle position based on double coils is proposed. By analyzing the change trend of the pickup voltage in the detection coil, the correspondence among the lateral deviation distance, the offset angle and the pickup voltage is obtained by difference ratio sum method, the position information of electric vehicle will be worked out. Then the PID with variable structure was deployed algorithm to realize the self-correction of the electric vehicle driving route. The construction of experimental platform verifies the feasibility of the positioning method. The results revealed that when a lateral deviation takes place, this method can guarantee the automatic correction to the path of an electric vehicle during the dynamic wireless charging process. The advantages of this method are high sensitivity, fast correction speed, a simple structure, etc. [ABSTRACT FROM AUTHOR]

In this paper, simultaneous wireless information and power transfer (SWIPT) transmissions with multiple-input single-output transceiver pairs are considered. In each pair, a multi-antenna transmitter sends data and energy to a single-antenna receiver with a signal-splitting structure and a non-linear energy harvesting model. Each transceiver pair tries to achieve high individual harvested energy efficiency, and uses artificial noise (AN) to protect the information from being overheard by other users that cooperate like a virtual eavesdropper. The weighted sum user-centric harvested energy-efficiency maximisation problem is formulated under constraints on the required signal-to-interference-plus-noise ratio (SINR) at each receiver, plus a limited SINR for virtual eavesdroppers and limited transmit power at each transmitter. The optimal precoding beamforming, AN, and signal-splitting factors are obtained by two proposed algorithms. The first solution exploits semidefinite relaxation and sequential parametric convex approximation techniques to convert the non-convex problem to a series of convex subproblems with matrix variables. We obtain optimal beamforming vectors along with an optimal covariance matrix for AN. The second solution directly utilizes beamforming approximation and obtains a low complexity solution for the convex subproblem. Moreover, we need to apply the feasible point pursuit method. Finally, numerical evaluations are provided in comparison with some benchmark schemes. [ABSTRACT FROM AUTHOR]

Rectennas are key contributors in wireless power transmission. Such prominent technology requires intensive works to gain a better performance thus a reliable energy source. In this paper, we present an electromagnetic model of rectenna using nonlinear resolution approach. This was achieved by a hybrid MoM-GEC (the Moments method combined to the generalized equivalent circuit) and the Harmonic balance method. The structure presenting the rectenna was given in a network form making it a flexible and reconfigurable model. The proposed method was demonstrated using a patch antenna and a Schottky diode as a rectifier circuit. The given current density and field distributions validated using HFSS software proves the accuracy of the obtained solutions. Moreover, a study of the RF-DC conversion efficiency is presented to discuss the performance of the rectenna. Finally, results show that this is a simple but effective technique to study the rectifying antenna for different topologies and technologies. [ABSTRACT FROM AUTHOR]

The performance and potential of energy-harvesting devices depend strongly on the performance and specific properties of materials and used technology. The recent explosion in capability of embedded electronics has not been matched by battery technology. The slow growth of battery energy density has limited device lifetime and added volume and weight. The amount of energy from harvesting is typically small and variable, requiring circuits and architectures which are low power and can scale their power consumption with user requirements and available energy. The energy harvesting research falls into two key areas. One is developing optimal structures of energy harvesting and the other is designing electronic circuits that are efficient enough to store the generated charge. Optimization of microelectronic devices to reduce energy consumption, while all devices strive to achieve good efficiency, balancing performance and power consumption, the application area will dictate design constraints such as size, energy budget, and maximum power. Regarding the research area of optimal design of electronic circuits, a highly efficient CMOS rectifier for vibrational energy harvesting system is proposed. Based on the design considerations, rectifier plays an important role in the application of energy harvesting system and wireless power transfer system. So, the performance of the rectifier decides the efficiency of the system. The proposed low voltage Rectifier is designed for operating frequency of 13.56 MHz using two-stage structure and an Improved precision active diode under a standard 0.18um CMOS process can perform the minimum operating voltage is lower than previous published paper and the rectifier can work at a wide range of input voltage amplitudes of 0.45 V up to 1.95 V. So, the proposed rectifier is suitable to work in Different Types of vibrational energy harvesting system, Electrostatic Energy harvester, Electromagnetic Energy Harvester, Piezoelectric Energy Harvester. The proposed rectifier can achieve peak voltage conversion efficiency of over 81% and power efficiency over 79%. Simulated power consumption of the rectifier is 0.23uW, which is about 28% smaller than the best recently published results. [ABSTRACT FROM AUTHOR]

A modified symmetric split ring resonator (MSSRR) loaded bowtie antenna with multi-band features over a range of 1.6–7.1 GHz is proposed in this paper. The antenna is designed on FR4 substrate with relative permittivity εr = 4.1 and thickness 1.5 mm. The fabricated antenna size is 40 mm × 58 mm. The Modified Symmetric SRR used beneath the substrate is novel and consists of two circles that are broken into four quarter circles by four rods. The effect of MSSRR location and its geometry is investigated and analysed thoroughly. The measurement results of the fabricated antenna are in good agreement with the simulation results, which confirms the proposed antenna design's properties. ANSYS High Frequency Structural Simulator (HFSS) software is used for simulating the antenna. [ABSTRACT FROM AUTHOR]