Wireless power transfer (WPT) is an emerging technology that can realize electric power transmission over certain distances without physical contact, offering significant benefits to modern ...automation systems, medical applications, consumer electronics, etc. This paper provides a comprehensive review of existing compensation topologies for the loosely coupled transformer. Compensation topologies are reviewed and evaluated based on their basic and advanced functions. Individual passive resonant networks used to achieve constant (load-independent) voltage or current output are analyzed and summarized. Popular WPT compensation topologies are given as application examples, which can be regarded as the combination of multiple blocks of resonant networks. Analyses of the input zero phase angle and soft switching are conducted as well. This paper also discusses the compensation requirements for achieving the maximum efficiency according to different WPT application areas.
Dynamic wireless power transfer (WPT) is a practical method to solve electric vehicle (EV) range anxiety and reduce the cost of on-board batteries. This paper presents a novel dynamic WPT system that ...combines the advantages of pads array and segmental long coils coupler. In the proposed circuit, several paralleled LCC reactive power compensation networks (RPCNs) in the primary side were excited by a sole inverter and the power distribution was realized automatically; an auxiliary LCC network was proposed to regulate current in the primary coil to minimize the electromagnetic interference (EMI) and reduce the system's power loss. A scaled-down prototype of a dynamic wireless charging system was developed to prove the validity of the theoretical analysis.
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 millimeters to several hundred millimeters 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. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.
This article presents the state-of-the-art electric vehicle (EV) charging technologies that benefit from the wide bandgap (WBG) devices, which is regarded as the most significant revolution in the ...power electronics industry in the past few decades. First, the recent WBG device technology evolution, performance comparison, and reliability issues are introduced. Then, topology development, efficiency and power density boost, and cost reduction brought by the WBG devices for EV charging equipment, such as onboard chargers, fast-charging stations, and wireless chargers, are discussed. A figure of merit (FOM) for evaluating the performance of wireless chargers is also proposed. Finally, the EV charging technology roadmap forecast is presented based on the WBG devices' evolutionary trends.
Lightweight autonomous underwater vehicles (AUVs), powered by rechargeable batteries, are widely deployed in inshore surveying, environmental monitoring, and mine countermeasures. While providing ...valuable information in locations humans have difficulty accessing, limited battery capacity of such systems prevents extended mission times. In order to extend mission times, this paper proposes a three-phase wireless charging system that could be used in a field-deployable charging station capable of rapid, efficient, and convenient AUV recharging. Wireless charging should not, however, affect instrumentation located inside the AUV. Thus, a three-dimensional finite element analysis tool is employed to study the characteristics of magnetic fields inside the AUV during three-phase charging. Simulation results reveal that the magnetic field generated by the proposed three-phase coil structure is concentrated away from the center of the AUV, where instrumentation would nominally be located. Detailed circuit analysis and compensation method to achieve resonance on both transmitter's and receiver's sides are also given. To validate the proposed concept, a three-phase wireless charging system is developed. Experimental results demonstrate that the system is able to transfer 1.0 kW with a dc-dc efficiency of 92.41% at 465 kHz.
This paper compares the characteristics of the series-series and double-sided Inductor-Capacitor-Capacitor (LCC) compensation topologies for electric vehicle (EV) wireless chargers. Both the ...well-tuned and mistuned topologies for the two compensation methods are analyzed in detail. The mistuning considered here is mainly caused by the variations of the relative position between the primary and secondary sides. The output power displacements caused by mistuning are compared for both compensation topologies, as well as the impacts of the load variations on the performances of the mistuned topologies. The voltage and current stresses on components are also studied. The comparative result shows that the double-sided LCC compensation topology is less sensitive to mistuning. A double-sided LCC-compensated EV wireless charger system with up to 7.7-kW output power is built to verify the analysis results. A peak efficiency of 96% from dc power source to battery load is achieved.
The successful commercialization of wireless power transfer (WPT) technology in mobile phones, laptops, and electric vehicles requires a safe, reliable, and efficient charging infrastructure. A metal ...object, such as a coin, a key, or a nail, however, may be inadvertently exposed, by close proximity, to the magnetic fields generated by the WPT coupler, creating a potential safety hazard and affecting the electrical characteristics of the WPT system. In addition, the magnetic fields may produce adverse symptoms, such as dizziness and breathlessness, in living objects near the charging systems. This article provides a current state of the art review of all available designs for detecting metal and living objects in WPT systems. Working principles and qualitative comparisons in terms of sensitivity, accuracy, and cost of major detection methods are presented to reveal their inherent limitations and available applications. Finally, a number of research topics on foreign object detection are suggested to encourage more researchers to make contributions to the development and commercial application of wireless charging systems.
Wireless power transfer system (WPTS)-based wireless electric vehicles, classified into roadway-powered electric vehicles (RPEVs) and stationary charging electric vehicles (SCEVs), are in the ...spotlight as future mainstream transportations. RPEVs are free from serious battery problems such as large, heavy, and expensive battery packs and long charging time because they get power directly from the road while moving. The power transfer capacity, efficiency, lateral tolerance, electromagnetic field, air-gap, size, weight, and cost of the WPTSs have been improved by virtues of innovative semiconductor switches, better coil designs, roadway construction techniques, and higher operating frequency. Recent advances in WPTSs for RPEVs are summarized in this review paper. The fifth- and sixth-generation online electric vehicles, which reduce infrastructure cost for commercialization, and the interoperability between RPEVs and SCEVs are addressed in detail in this paper. Major milestones of the developments of other RPEVs are also summarized. The rest of this paper deals with a few important technical issues such as coil structures, power supply schemes, and segmentation switching techniques of a lumped inductive power transfer system for RPEVs.
•Reviewed technology advances and sustainability performance of WPT for EVs.•Identified the technical bottlenecks for improving system performance.•Highlighted system performance of case studies and ...real-world demonstrations.•Evaluated energy, environmental, economic, and societal impacts of WPT deployment.•Defined WPT challenges and opportunities for enhancing future sustainable mobility.
Wireless power transfer (WPT), which transmits power by an electromagnetic field across an intervening space, provides the prospect of new opportunities for electric vehicles (EVs) to enhance sustainable mobility. This review article evaluates WPT technology for EV applications from both technical and sustainability perspectives. The objectives of this review include: (1) to present the state-of-the-art technical progress and research bottlenecks in WPT development and applications in the transportation sector; (2) to characterize the demonstrations of the real-world deployment of WPT EV systems; and (3) to evaluate the sustainable performance and identify challenges and opportunities for improvement. From the technical perspective, progress on coil design, compensation topologies, and power electronics converters and control methods are reviewed with a focus on system performance. From the sustainability perspective, performance is defined in terms of energy, environmental, and economic metrics, and policy drivers and issues of health and safety are also examined.
This paper proposes a double-sided LC-compensation circuit for a loosely coupled, long-distance capacitive power transfer (CPT) system. A CPT system usually contains two pairs of metal plates as the ...capacitive coupler. An LC-compensation circuit resonates with the coupler to generate high voltages, and corresponding electric fields, to transfer power. When the compensation circuit is used on both the primary and secondary sides, it results in a double-sided LC-compensated CPT system. The working principle and frequency properties of the CPT system are analyzed. The results show a similarity with the series-series-compensated inductive power transfer system, which has both constant-voltage (CV) and constant-current (CC) working modes. LC-compensation is also compared with LCLC -compensation in terms of power, frequency properties, and output efficiency. A 150-W double-sided LC -compensated CPT prototype is designed and implemented to demonstrate a loosely coupled CPT system with 2.16% coupling coefficient. For both CC and CV working modes, the experimental results achieve dc-dc efficiencies higher than 70% across an air-gap distance of 180 mm with a switching frequency of 1.5 MHz.
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