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Wireless charging standards for consumer devices include specifications for charging multiple receive devices simultaneously. However if the devices are not all the same size or if they require different amounts of power, these existing standards may be incapable of charging multiple devices efficiently. This paper provides an overview of a complete wireless power transfer system that is capable of...
A 2-stage X-band GaN MMIC operating as a power amplifier and rectifier is measured in a wireless power transfer link. The PA operates at 9.9 GHz in class-AB and achieves 10W of output power and >20 dB of gain. As a rectifier, the MMIC achieves over 52% RF-DC conversion efficiency at a power level of >8W. In a wireless powering link at a distance of 5 cm, the system achieves 10% DC-DC efficiency...
In this paper the possibility of combining resonant magnetic coupling and resonant electrical coupling is proposed and discussed. Equivalent circuit models are used to demonstrate that efficiency can be improved quite significantly using a hybrid approach. A comparison between resonant magnetic coupling only, resonant electrical coupling only and several hybrid combinations is provided.
A capacitive power coupler has been devised using a hydrodynamic journal bearing assembly that facilitates sufficient coupling for kilowatt-scale non-contact power transfer to a rotating load. The capacitive coupler, combined with associated driving circuitry, is an efficient low maintenance solution for powering a variety of rotating or pivoting electrical loads in machines and automation. A hydrodynamic...
Wireless power transfer (WPT) technology enables convenient and automatic battery charging for unmanned aerial vehicles (UAVs). However, in WPT charging systems, strong electromagnetic fields (EMFs) are inevitably generated and the power source contains a wide range of harmonics. In this paper, we propose an automated resonant wireless power transfer charger for UAV with three-phase magnetic field...
In the wireless power transmission/transfer (WPT) research field, great efforts are currently being devoted to the design of specific types of waveforms which leads to high power conversion efficiencies. This is mainly achieved by using those communication signals with a large peak-to-average power ratio (PAPR). In this work, the exploitation of commonly-employed radar signals featuring this high...
Non-leak energy technology is essential for high power system in microwave power transmission (MPT). MPT mainly consists of a transmitting antenna and a receiving antenna, and we focus on the receiving antenna. Non-leak energy system requires the receiving antenna to receive all the energy which reaches the antenna surface. It is known that the receiving efficiency of an infinite dipole array antenna...
Manufacturing electronic devices requires accordance to the electromagnetic compatibility requirements. Taking into account the growing importance of inductive wireless power transfer at higher frequencies, it is important that one can already early in the design process characterize the emissions. In this work, we describe the experimental methods which could be used for the characterization of as...
In this study, we propose the use of a radio wave hose as a new transmission line and present the result of our basic study on a wireless power transmission method using microwaves. We fabricated a prototype radio wave hose by plating and processing into a resin hose, with a conductive coating and evaluated its transmission characteristics using electromagnetic field simulation and basic experimentation...
Designers of on-body health sensing devices with inductive power transfer (IPT) face a number of trade-offs. Safe exposure limits should be maintained, and protective housing and padding are generally needed; however, these impose compromises on the power-transfer-system design. This paper analyses these trade-offs and proposes a design route to achieving high power transfer in the presence of field...
A resonant wireless power transfer (WPT) system that allows for free positioning of a wearable device about a 360° axis of rotation and simultaneous charging of a mobile phone is proposed. A 3D transmitter coil structure is introduced to provide a cylindrical charging surface with a uniform magnetic field. A prototype charging system including an amplifier and a rectifier operating at 6.78 MHz is...
In this research, the feasibility of a real-time active matching circuit for biomedical WPT applications is discussed. Also, the genetic-algorithm based matching circuit design method utilizing discrete circuit components is introduced and the practicality of active matching circuits for WPT is verified with preliminary measurement results featuring a maximum of 3 dB of improvement in transmission...
A novel magnetically-coupled resonant wireless power transfer (MCR-WPT) system using an array of printed spiral coil (PSC) resonators is presented to expand the receiving area. The resonator array is excited with a single planar driving loop to yield uniform magnetic field distribution at the receiver plane. First, the performance of a conventional transmitter coil array consisting of one transmitting...
A method of wirelessly transmitting power to multiple small moving or rotating devices by means of UHF radio energy has been devised. The transmission frequency was set to 430 MHz to keep the antenna small (relative to an antenna for the SHF region) and to enable the use of inexpensive off-the-shelf rectifiers. The system can supply power to multiple targets within the beam angle of the transmitting...
In this paper, we propose a near field coupling based wireless power transfer (WPT) system with circularly polarized magnetic field. With a pair of orthogonal resonant coils arranged to generate a circularly polarized near field, we show that the power transfer efficiency is largely maintained in case of rotational misalignment. Furthermore, by arranging the coils close to a metal surface, the power...
The wireless power transfer (WPT) system has been actively developed in recent years. Since the electromagnetic field leaked from the WPT system may cause a false operation of other electronic devices, an analysis of the leaked electromagnetic field is significant issue for its practical realization. This paper presents that the electromagnetic field leaked from the WPT system installed in a case-study...
This paper evaluates simultaneous wireless power transfer and backscattering data communication through Multisine (MS) signals. For this purpose a MS-capable RFID reader is built from the ground up, and it is shown that: 1) the MS reader presents an improved reading range, 2) through proper MS design, MS receiver complexity is reduced to that of a regular CW receiver; 3) MS multi-frequency diversity...
The feasibility of transferring power over a wide range of distances and orientation offsets has been proven in air for various commercial applications, notably in the electric vehicle industry, by using two loosely-coupled RLC circuits that are tuned to resonate at the same frequency. Key system concepts for resonant wireless power transfer, such as frequency splitting, maximum operating distance,...
Electric vehicles (EVs) are becoming popular in the United States. Battery EVs, powered exclusively by electricity, draw more attention because they emit zero exhaust fumes, transfer energy efficiently and can be more economical compared with internal combustion automobiles. This paper presents a comprehensive analysis of the real-world charging, driving and energy consumption patterns of electric...
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