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  Subjects -> ELECTRONICS (Total: 152 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 1)
Advances in Electronics     Open Access   (Followers: 3)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 5)
Advances in Microelectronic Engineering     Open Access   (Followers: 2)
Advances in Power Electronics     Open Access   (Followers: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 89)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 12)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 2)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 6)
Archives of Electrical Engineering     Open Access   (Followers: 9)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 9)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 15)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 5)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 2)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 13)
China Communications     Full-text available via subscription   (Followers: 4)
Circuits and Systems     Open Access   (Followers: 9)
Consumer Electronics Times     Open Access   (Followers: 4)
Control Systems     Hybrid Journal   (Followers: 24)
Electronic Design     Partially Free  
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 3)
Electronics     Open Access   (Followers: 9)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 5)
Electronics Letters     Hybrid Journal   (Followers: 19)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 23)
Energy Harvesting and Systems : Materials, Mechanisms, Circuits and Storage     Hybrid Journal   (Followers: 1)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 9)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Frequenz     Hybrid Journal   (Followers: 3)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 2)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 21)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 3)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 15)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 13)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 17)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 12)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 3)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 6)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 10)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 13)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 17)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 14)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 20)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 8)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 6)
IET Power Electronics     Hybrid Journal   (Followers: 13)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 10)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 9)
IETE Technical Review     Open Access   (Followers: 4)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 3)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 2)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 5)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 20)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 3)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 11)
International Journal of Antennas and Propagation     Open Access   (Followers: 7)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 1)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Computer & Electronics Research     Full-text available via subscription   (Followers: 2)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 4)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 5)
International Journal of Nanoscience     Hybrid Journal  
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 2)
International Journal of Power Electronics     Hybrid Journal   (Followers: 8)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 2)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 2)
International Journal of Superconductivity     Open Access  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 9)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 10)
International Transaction of Electrical and Computer Engineers System     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 2)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription  
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 4)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 2)

        1 2 | Last

Journal Cover   IEEE Transactions on Power Electronics
  [SJR: 2.866]   [H-I: 128]   [20 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0885-8993
   Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [176 journals]
  • IEEE Transactions on Power Electronics publication information
    • Abstract: Provides a listing of the editors, board members, and current staff for this issue of the publication.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Table of Contents
    • Abstract: Presents the table of contents for this issue of the publication.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • IEEE Power Electronics Society Information
    • Abstract: Provides a listing of the editors, board members, and current staff for this issue of the publication.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Selective Wireless Power Transfer to Multiple Loads Using Receivers of
           Different Resonant Frequencies
    • Authors: Zhang; Y.;Lu, T.;Zhao, Z.;He, F.;Chen, K.;Yuan, L.;
      Pages: 6001 - 6005
      Abstract: In multiple receivers of resonant wireless power transfer, selective power flow among the loads is an important issue. This paper proposes a new method to control power division. The two-coil structure with different resonant frequencies of the sending and receiving loops is modeled and analyzed. The efficiency is proved to peak at the resonant frequency of the receiving loop, regardless of the resonant frequency of the sending loop. Using this feature, selective power transfer can be achieved by setting the receiving loops at different resonant frequencies. The efficiency of a particular load is greatly influenced by the driving frequency. The multiple-load system with different resonant frequencies is modeled and the efficiency expression of each load is deduced. The mutual inductances of the receiving coils have a small impact on the efficiency distribution. The closer the resonant frequencies of the receiving loops, the less isolated the related loads. The calculations and the experiments confirm the analysis.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Compact Frequency Reconfigurable Rectenna for 5.2- and 5.8-GHz Wireless
           Power Transmission
    • Authors: Lu; P.;Yang, X.;Li, J.;Wang, B.;
      Pages: 6006 - 6010
      Abstract: A compact reconfigurable rectifying antenna (rectenna) has been proposed for 5.2- and 5.8- GHz microwave power transmission. The proposed rectenna consists of a frequency reconfigurable microstrip antenna and a frequency reconfigurable rectifying circuit. Here, the use of the odd-symmetry mode has significantly cut down the antenna size by half. By controlling the switches installed in the antenna and the rectifying circuit, the rectenna is able to switch operation between 5.2 and 5.8 GHz. Simulated conversion efficiencies of 70.5% and 69.4% are achievable at the operating frequencies of 5.2 and 5.8 GHz, respectively, when the rectenna is given with an input power of 16.5 dBm. Experiment has been conducted to verify the design idea. Due to fabrication tolerances and parametric deviation of the actual diode, the resonant frequencies of the rectenna are measured to be 4.9 and 5.9 GHz. When supplied with input powers of 16 and 15 dBm, the measured maximum conversion efficiencies of the proposed rectenna are found to be 65.2% and 64.8% at 4.9 and 5.9 GHz, respectively, which are higher than its contemporary counterparts.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Double-Sided LCLC-Compensated Capacitive Power Transfer
           System for Electric Vehicle Charging
    • Authors: Lu; F.;Zhang, H.;Hofmann, H.;Mi, C.;
      Pages: 6011 - 6014
      Abstract: A double-sided LCLC-compensated capacitive power transfer (CPT) system is proposed for the electric vehicle charging application. Two pairs of metal plates are utilized to form two coupling capacitors to transfer power wirelessly. The LCLC-compensated structure can dramatically reduce the voltage stress on the coupling capacitors and maintain unity power factor at both the input and output. A 2.4-kW CPT system is designed with four 610-mm × 610-mm copper plates and an air gap distance of 150 mm. The experimental prototype reaches a dc–dc efficiency of 90.8% at 2.4-kW output power. At 300-mm misalignment case, the output power drops to 2.1 kW with 90.7% efficiency. With a 300-mm air gap distance, the output power drops to 1.6 kW with 89.1% efficiency.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Guest Editorial Special Issue on Wireless Power Transfer
    • Authors: Rim; C.T.;Chris Mi, C.;
      Pages: 6015 - 6016
      Abstract: The papers in this special section focus on the technologies and applications that support wireless power transfer (WPT). The papers focus on state-of-the-art research, experimentation, and development, as well as future trends in the modeling, analysis, design, control, and testing of wireless power systems for mobile devices, electric vehicles (EV), etc. WPT is increasingly utilized in mobile devices, industrial applications, medical equipment, and transportation. Despite its advantages, however, WPT technology has not been adopted for widespread use. This delay may be because the technology remains quite expensive and less efficient than other available technologies. Furthermore, electromagnetic field and electromagnetic interference can become severe for a longer and higher power transfer, and they should be reasonably mitigated. Continued effort and innovation inWPT will be needed to open an era of wireless power adoption.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Survey of Wireless Power Transfer and a Critical Comparison of Inductive
           and Capacitive Coupling for Small Gap Applications
    • Authors: Dai; J.;Ludois, D.C.;
      Pages: 6017 - 6029
      Abstract: Inductive power transfer (IPT) and capacitive power transfer (CPT) are the two most pervasive methods of wireless power transfer (WPT). IPT is the most common and is applicable to many power levels and gap distances. Conversely, CPT is only applicable for power transfer applications with inherently small gap distances due to constraints on the developed voltage. Despite limitations on gap distance, CPT has been shown to be viable in kilowatt power level applications. This paper provides a critical comparison of IPT and CPT for small gap applications, wherein the theoretical and empirical limitations of each approach are established. A survey of empirical WPT data across diverse applications in the last decade using IPT and CPT technology graphically compares the two approaches in power level, gap distance, operational frequency, and efficiency, among other aspects. The coupler volumetric power density constrained to small gap sizes is analytically established through theoretical physical limitations of IPT and CPT. Finally, guidelines for selecting IPT or CPT in small gap systems are presented.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • General Unified Analyses of Two-Capacitor Inductive Power Transfer
           Systems: Equivalence of Current-Source SS and SP Compensations
    • Authors: Sohn; Y.H.;Choi, B.H.;Lee, E.S.;Lim, G.C.;Cho, G.;Rim, C.T.;
      Pages: 6030 - 6045
      Abstract: A general and systematic comparison of eight compensation schemes in the inductive power transfer system (IPTS) of single magnetic coupling and two capacitors is proposed in this paper. The characteristics of series–series (SS), series–parallel (SP), parallel–series (PS), and parallel–parallel (PP) compensation schemes for a voltage source or a current source are widely explored in terms of maximum efficiency, maximum power transfer, load-independent output voltage or current, magnetic coupling coefficient (k) independency, and allowance of no magnetic coupling ( k = 0 ). Through comparative analyses using a general unified IPTS model, the current-source-type SS and SP are found to be superior to other compensation schemes in terms of the five criteria mentioned above, and they are found to have nearly the same efficiency, load power, and component stress characteristics for the same load quality factor. A design guideline for the current­-source-type SS and SP is suggested and experimentally verified by a 200-W prototype of air coils at 100 kHz.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Lumped Impedance Transformers for Compact and Robust Coupled Magnetic
           Resonance Systems
    • Authors: Choi; B.H.;Lee, E.S.;Huh, J.;Rim, C.T.;
      Pages: 6046 - 6056
      Abstract: An innovative coupled magnetic resonance system (CMRS), introducing two lumped impedance transformers, is proposed. There are three major magnetic couplings between coils in CMRS: source-transmitter (Tx), Tx-receiver (Rx), and Rx-load couplings. Except for Tx-Rx coupling, other couplings do not directly contribute to wireless power transfer. Hence, in this paper, this miscellaneous coupling is replaced with a lumped transformer with ferrite core. Because there is only a Tx-Rx coupling, the CMRS becomes compact in size and robust to ambient changes. Moreover, the design of CMRS is drastically simplified without complicated multiresonance tunings due to little magnetic flux linkage from the source coil or load coil. Coreless coils are used for Tx and Rx coils to examine the characteristics of CMRS with lumped transformers. A detailed static analysis on the explicit circuit model of the proposed CMRS and design procedures are fully established. Experiments for 1- and 10-W prototype CMRSs with a class-E inverter at the switching frequency of 500 kHz, where the quality factors are less than 100, verified the usefulness of the proposed model, achieving 80% of the maximum Tx coil-to-load efficiency. It is concluded in this paper that the conventional CMRS, in general, is just a special form of an inductive power transfer system where the quality factor is extremely high.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Reconfigurable Magnetic Resonance-Coupled Wireless Power Transfer System
    • Authors: Dang; Z.;Cao, Y.;Abu Qahouq, J.A.;
      Pages: 6057 - 6069
      Abstract: This paper presents a method for a reconfigurable magnetic resonance-coupled wireless power transfer (R-MRC-WPT) system in order to achieve higher transmission efficiency under various transmission distance and/or misalignment conditions. Higher efficiency, longer transmission distance, and larger misalignment tolerance can be achieved with the presented R-MRC-WPT system when compared to the conventional four-coil MRC-WPT (C-MRC-WPT) system. The reconfigurability in the R-MRC-WPT system is achieved by adaptively switching between different sizes of drive loops and load loops. All drive loops are in the same plane and all load loops are also in the same plane; this method does not require mechanical movements of the drive loop and load loop and does not result in the system volume increase. Theoretical basis of the method for the R-MRC-WPT system is derived based on a circuit model and an analytical model. Results from a proof-of-concept experimental prototype, with transmitter and receiver coil diameter of 60 cm each, show that the transmission efficiency of the R-MRC-WPT system is higher than the transmission efficiency of the C-MRC-WPT system and the capacitor tuning system for all distances up to 200 cm (∼3.3 times the coil diameter) and for all lateral misalignment values within 60 cm (one coil diameter).
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Dynamic Resonant Matching Method for a Wireless Power Transmission
    • Authors: Waffenschmidt; E.;
      Pages: 6070 - 6077
      Abstract: Wireless power transmission systems can be optimized by matching the resonance frequency of a receiver. However, in certain applications, such as, e.g., a multireceiver system, it is desired to match the individual resonance frequencies of the receiver to a fixed (e.g., common) operation frequency. In this publication, a method is proposed to match the resonant frequency dynamically without changing the physical value of the components. Instead, it is changed “virtually” by a method, which is named “frozen resonance state” by the author. The basic idea is to maintain the state of a resonant circuit (to “freeze” the state) for a fraction of the resonant period, e.g., by freewheeling the current of the resonant inductor or maintaining the voltage of the resonant capacitor. This additional time extends virtually the resonant period leading to an effective lower resonant frequency. By adjusting the additional time, the effective resonant frequency can be matched to the operation frequency individually for each receiver. This publication explains the basic idea more in detail and gives an overview of the different possible circuit topologies. Furthermore, the method is applied to an exemplary receiver of a capacitive wireless power transmission system, where measurements are presented.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Inductive Power Transfer System With Self-Calibrated Primary Resonant
    • Authors: Trigui; A.;Hached, S.;Mounaim, F.;Ammari, A.C.;Sawan, M.;
      Pages: 6078 - 6087
      Abstract: Inductive power transfer (IPT) is a commonly employed technique for wirelessly supplying power to implantable medical devices. A major limit of this approach is the sensitivity of the inductive link to coupling factor variations between transmitting and receiving coils. We propose in this paper a new method for compensating these variations and improving the inductive link efficiency. The proposed technique is based on a mechatronic module that dynamically tunes the primary resonant capacitor value in order to maintain the resonance state of the IPT system. The module is able to maintain resonance state for apparent primary inductance range at least from 0.5 to 5 \mu {\rm H} using a high capacitance resolution of 0.032 pF. Experimentations conducted on a 13.56-MHz IPT system showed a 65% higher power transfer compared to a traditional IPT system.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Splitting Frequency Diversity in Wireless Power Transmission
    • Authors: Nguyen; H.;Agbinya, J.I.;
      Pages: 6088 - 6096
      Abstract: This paper investigates the methodology to create multiple frequency modes in a multiresonator system of one transmitter and multiple receivers based on the circuit theory. The multiple frequencies from natural responses of magnetic couplings could be obtained by determining the eigenvalues of a matrix equation. This potentially allows us to diversify transmissions to and from devices. Theoretical calculations and experiments show similar results of the multiple frequencies at given coupling conditions. Models of two, three, and four coils in straight line demonstrate the splitting mode in the spectral domain, which are validated by envelopes of signals. In measurements, three frequencies of 525, 625, and 695 kHz, and four frequencies of 495, 590, 670, and 755 kHz are achieved at the receiver for three- and four-coil models, respectively, when coils are equally distanced by 2 cm. When coupling coefficient of every adjacent coil in three-coil model is 0.2, aggregating the peak power at two and three splitting modes result in 28% and 71%, respectively, more power than that at resonance frequency. Similarly, with two, three, and four modes in four-coil model, the increases are 43%, 23%, and 33% with two, three, and four modes, respectively.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Method of Using Nonidentical Resonant Coils for Frequency Splitting
           Elimination in Wireless Power Transfer
    • Authors: Lyu; Y.;Meng, F.;Yang, G.;Che, B.;Wu, Q.;Sun, L.;Erni, D.;Li, J.L.;
      Pages: 6097 - 6107
      Abstract: In this paper, an efficient method is proposed to eliminate frequency splitting in nonradiative wireless power transfer via magnetic resonance coupling. In this method, two nonidentical resonant coils (NIRCs) are used as wireless power transmitter and receiver, respectively. According to the elliptic integral term in the analytical expression, the pole of the mutual inductance function with respect to transfer distance can be eliminated by using the two NIRCs, and hence overcoupling between transmitter and receiver with close transfer distance is avoided. Therefore, frequency splitting caused by overcoupling can be suppressed and stable output power can be achieved. The NIRCs are analytically calculated, numerically simulated and finally, fabricated and tested to verify the theory. All the calculated and experimental results show that frequency splitting is completely eliminated and uniform voltage across the load is achieved. Furthermore, lateral misalignment between the NIRCs barely introduces frequency splitting, and the suppression level of frequency splitting can also be controlled freely.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Design Considerations to Reduce Gap Variation and Misalignment Effects for
           the Inductive Power Transfer System
    • Authors: Zheng; C.;Ma, H.;Lai, J.;Zhang, L.;
      Pages: 6108 - 6119
      Abstract: An inductive power transfer (IPT) system usually consists of four parts: an ac–dc power factor correction (PFC) converter, a high-frequency dc–ac inverter, a compensation network comprising a loosely coupled transformer (LCT) and the resonant capacitors, and a rectification output circuit. Due to the relatively large air gap, the magnetic coupling coefficient of the IPT system is significantly lower than that with tightly coupled transformer. As a result, the efficiency of the IPT system is always a main concern for applications with possible gap variation or misalignment condition. To ensure high power transfer efficiency, these IPT systems should have high tolerance for different gap variation and horizontal misalignment conditions. In this paper, the effect of coupling coefficient deviation to compensation network efficiency is analyzed, and design considerations to reduce gap and misalignment effects for the IPT system are proposed. By using finite-element analysis simulation method, the performance of different transmitter and receiver coil dimensions is compared. In order to validate the performance of the proposed design considerations, a 100-W hardware prototype with two sets of LCT is built and the corresponding experiments are carried out. As compared to the symmetrical LCT architecture, the proposed asymmetrical LCT prototype improves the coupling coefficient reduction from 68% to 28% when the gap varies from 6 to 20 mm and from 89% to 31% when the misalignment ranges from 0 to 50 mm. Therefore, the efficiency deviation for the asymmetrical LCT is maintained within 3.5% over the entire tested gap variation and misalignment ranges.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Switched Compensator for Contactless Power Transfer Systems
    • Authors: Matsumoto; H.;Neba, Y.;Asahara, H.;
      Pages: 6120 - 6129
      Abstract: Contactless power transfer systems require compensators to improve power factor degradation caused by significant leakage inductance in the contactless power transformer. The most commonly used compensators are LC series- and parallel-resonant compensators. In this paper, we present a comparison between the characteristics of the compensators with a focus on transfer efficiency. Based on these characteristics, a compensator capable of switching between the LC parallel- and series-resonant topologies is proposed, and its changeover algorithm is explained. The proposed compensator was experimentally examined and was found to perform efficiently over a wider range of output power than conventional LC resonant compensators.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Compact and Efficient Bipolar Coupler for Wireless Power Chargers: Design
           and Analysis
    • Authors: Deng; J.;Li, W.;Nguyen, T.D.;Li, S.;Mi, C.C.;
      Pages: 6130 - 6140
      Abstract: Compactness and efficiency are the two basic considerations of the wireless battery chargers for electric vehicles (EVs) and plug-in hybrid EVs. The double-sided LCC compensation topology for wireless power transfer (WPT) has been proved to be one of the efficient solutions lately. However, with the increase of the numbers of compensation components, the volume of the system may become larger, which makes it less attractive. To improve the compactness, a bipolar coupler structure with a compensation-integrated feature is proposed. The inductors of the LCC compensation networks are designed as planar-type and attached to the power-transferring main coils. Extra space and magnetic cores for the compensated inductors outside of the coupler are saved. The cost is that extra couplings between the compensated coils (inductors) and the main coils are induced. To validate the feasibility, the proposed coupler is modeled and investigated by 3-D finite-element analysis tool first. The positioning of the compensated coils, the range of the extra couplings, and the tolerance to misalignment are studied. This is followed by the circuit modeling and characteristic analysis of the proposed WPT topology based on the fundamental harmonic approximation. At last, a 600 mm × 600 mm with a nominal 150-mm-gap wireless charger prototype, operated at a resonant frequency of 95 kHz and a rated power of 5.6 kW has been built and tested. A peak efficiency of 95.36% from a dc power source to the battery load is achieved at rated operation condition.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Analysis of Coplanar Intermediate Coil Structures in Inductive Power
           Transfer Systems
    • Authors: Kamineni; A.;Covic, G.A.;Boys, J.T.;
      Pages: 6141 - 6154
      Abstract: Intermediate couplers have been shown to increase the coupling from primary to secondary pads in inductive power transfer (IPT) systems. This paper investigates embedding a coplanar intermediate coupler coil with the primary coil inside the primary pad to boost the coupling to the secondary pad and improve the efficiency of the system. Several coil designs are simulated and a mathematical model is developed to evaluate the efficiency of parallel–parallel and series–series tuned systems. As shown a coplanar, independently tuned intermediate coupler coil improves the efficiency of a series–series-tuned system since it reduces source losses. However, there appears to be no benefit to having an intermediate coupler with a parallel–parallel-tuned system. Furthermore, boosts in coupling are a result of adding extra current carrying windings to the primary pad and simulations show that operating the system as a traditional two coil IPT system may be simpler and more effective based on tuning topology. An experimental system was constructed to validate the simulations.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Unified Approach to the Calculation of Self- and Mutual-Inductance for
           Coaxial Coils in Air
    • Authors: Hurley; W.G.;Duffy, M.C.;Zhang, J.;Lope, I.;Kunz, B.;Wolfle, W.H.;
      Pages: 6155 - 6162
      Abstract: This paper extends a previous formula for the mutual inductance between single-turn coils to include all coils in air with rectangular cross sections, without any restrictions on the dimensions (including overlapping coils). The formula is compared with a wide spectrum of examples from the literature and agreement is excellent in every case. Experimental results are presented to validate the formula for both solenoid and disk coils. The formula is relevant to coreless transformers, inductive coupling, wireless power transfer, and leakage inductance in resonant converters.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Three-Dimensional Charging via Multimode Resonant Cavity Enabled Wireless
           Power Transfer
    • Authors: Chabalko; M.J.;Sample, A.P.;
      Pages: 6163 - 6173
      Abstract: The majority of existing wireless power solutions are capable of 2-D surface charging of one or two devices, but are not well suited to deliver power efficiently to large numbers of devices placed throughout a large 3-D volume of space. In this paper, we propose an unexplored type of wireless power transfer system based on electromagnetic cavity resonance. Here, we use the natural electromagnetic modes of hollow metallic structures to produce uniform magnetic fields which can simultaneously power multiple small receiver coils contained almost anywhere inside. An analytical model is derived that predicts the coupling coefficient and power transfer efficiency from the cavity resonator to a small coil. These predictions are verified against simulated results with a coefficient of determination of 0.9943. By using two resonant modes, we demonstrate that a 3-in diameter receiver can be powered in nearly any location in a 140 cubic foot test chamber, at greater than 50% efficiency. Additionally, we show that ten receivers can be powered simultaneously and that this system is capable of recharging consumer electronics such as a cell phone.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Employing Load Coils for Multiple Loads of Resonant Wireless Power
    • Authors: Zhang; Y.;Lu, T.;Zhao, Z.;He, F.;Chen, K.;Yuan, L.;
      Pages: 6174 - 6181
      Abstract: The load coils are employed for multiple loads of resonant wireless power transfer in this paper. With the addition of the load coil, this three-coil structure has easy access to transferring power to multiple loads with the advantages of a compact structure and controllable power flow. Both single-load transfer and multiple-load transfer are modeled and analyzed by means of the circuit theory. The transfer quality factor and the load matching factor are utilized in the analysis of efficiency. In the single-load transfer, the load matching condition is fully explored. Based on the single-load transfer, the multiple-load transfer is researched. The double-load transfer, acting as an illustration, is studied with the uncoupled and coupled load coils. Equivalent reflected resistances are introduced to decouple the model of the double-load transfer with coupled load coils mathematically. An experimental prototype is implemented to verify the aforementioned analysis. The experimental results agree with the theoretical calculations.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Magnetoinductive Waves and Wireless Power Transfer
    • Authors: Stevens; C.J.;
      Pages: 6182 - 6190
      Abstract: Recent research in wireless power transfer has highlighted the potential benefits for relaying power from source to receiver by a number of resonating relay coils coupled via mutual inductance. A number of researchers have reported experimental systems based on relay coils and have noted that power transfer efficiency to loads located at different points on the structure can vary widely. Such structures, often known as magnetoinductive waveguides are well known to carry signals known as magnetoinductive waves (MIW) when excited with a frequency in their passband. This paper presents an investigation into their impact on wireless power systems and methods by which negative effects may be minimized. Using the physics of magnetoinductive waves it becomes possible to understand the behavior of relay coil systems and to model them in a closed form. The effects of reflections and standing waves on a one-dimensional system are considered and their effect on the input impedance and the variation of matching conditions determined. An optimum receiver load is proposed based on the results and tested experimentally. A simple experimental demonstrator is used as a model for study, which achieves 58% efficient power transfer to a single load at any point on its length.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Magnetic Field Energy Harvesting Under Overhead Power Lines
    • Authors: Yuan; S.;Huang, Y.;Zhou, J.;Xu, Q.;Song, C.;Thompson, P.;
      Pages: 6191 - 6202
      Abstract: Condition monitoring for overhead power lines is critical for power transmission networks to improve their reliability, detect potential problems in the early stage, and ensure the utilization of the transmitting full capacity. Energy harvesting can be an effective solution for autonomous self-powered wireless sensors. In this paper, a novel bow-tie-shaped coil is proposed, which is placed directly under overhead power lines to scavenge the magnetic field energy. Compared to the conventional method by mounting the energy harvester on the power lines, this approach provides more flexibility and space to power bigger sensors such as the weather station. As the harvesting coil cannot entirely enclose the power lines, the demagnetization factor that is closely related to the core geometry should be considered and optimized. Thus a new bow-tie-shape core is designed to produce a much lower demagnetization factor (hence more power) than that of the conventional solenoid. The selection of core material is studied and found that Mn–Zn ferrite is the most suitable core material because it greatly reduces the eddy current losses and also has high permeability. Experiment results show that the bow-tie coil could have a power density of 1.86 μW/cm 3 when placed in a magnetic flux density of 7 \mu{\rm T_{\rms}} . This value is 15 times greater than the reported results under the same condition. If a longer bow-tie coil with more turns is placed in a magnetic flux density of 11 \mu{\rm T_{\rms}} , the produced power density is 103.5 μW/cm3, which is comparable to a solar panel working during a cloudy day. Thus, the proposed solution is a very efficient and attractive method for harvesting the magnetic field energy for a range of monitoring applications.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • An Inductive Power Transfer System With a High-Q Resonant Tank for Mobile
           Device Charging
    • Authors: Li; Q.;Liang, Y.C.;
      Pages: 6203 - 6212
      Abstract: Inductive power transfer (IPT), which employs the principle of electromagnetic induction, is widely applied to wireless charging applications. The efficiency of an IPT system is highly dependent on the quality factor (Q) of the power resonant tank. In this paper, a novel design on the structure of the resonant coil is used in the resonant tank to achieve a significantly high Q above 1000 for the IPT system. Compensating capacitors are used in both primary and secondary circuits to align the resonant frequencies in order for the system resonant status to be maintained by a frequency tracking circuit. The experimental results show that with a primary coil Q of 1200, the proposed IPT system allows power to be transferred at a maximum air gap distance to coil diameter ratio of 1.46 for a highest efficiency of 87% at the resonant frequency of 106 kHz.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Homogeneous Wireless Power Transfer for Move-and-Charge
    • Authors: Zhang; Z.;Chau, K.T.;
      Pages: 6213 - 6220
      Abstract: This paper presents a homogeneous wireless power transfer (WPT) technique to continuously energize the moving target. Due to the mobility of the charging target, the misalignment between the primary and secondary coils inevitably deteriorates the energy transfer performance by adopting the conventional WPT technique, so the constant energization mechanism is the most important issue for move-and-charge systems. The proposed homogeneous WPT technique utilizes the alternate winding design to gaplessly assemble primary coils, aiming to enhance the magnetic flux density. Besides, the vertical-and-horizontal secondary coil is also implemented to further improve the capability of acquiring energy for charging targets, especially in the area of the coils gap. In such ways, the proposed homogeneous WPT technique can effectively fulfil a continuous charging mechanism for moving targets. Also, this paper deduces the equivalent circuit model to analyze the mutual effect among multiple primary coils, which offers the theory-based view for the design of move-and-charge systems. Besides, both simulation and experimental results are provided to verify the feasibility of the proposed homogeneous WPT technique for move-and-charge systems.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • High-Efficiency Transcutaneous Energy Transfer for Implantable Mechanical
           Heart Support Systems
    • Authors: Knecht; O.;Bosshard, R.;Kolar, J.W.;
      Pages: 6221 - 6236
      Abstract: Inductive power transfer technology is a promising solution for powering implantable mechanical circulatory support systems, due to the elimination of the percutaneous driveline, which is still the major cause of severe infections. However, at the present time, no transcutaneous energy transfer (TET) system is commercially available and ready for long-term use. Specifically, the heating of the tissue due to power losses in the TET coils and the implanted electronic components are a major problem. The focus of this paper is, therefore, on the design and realization of a highly efficient TET system and the minimization of the power losses in the implanted circuits in particular. Parameter sweeps are performed in order to find the optimal energy transmission coil parameters. In addition, simple and meaningful design equations for optimal load matching are presented together with a detailed mathematical model of the power electronic stages. To achieve highest efficiencies, a high-frequency self-driven synchronous rectifier circuit with minimized volume is developed. Extensive measurements are carried out to validate the mathematical models and to characterize the performance of the prototype system. The optimized system is capable of transmitting 30 W of power with an efficiency greater than 95 %, even at a coil separation distance of 20 mm (0.79 in) and 70 mm (2.76 in) coil diameter.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Efficiency Evaluation of Laser Diode in Different Driving Modes for
           Wireless Power Transmission
    • Authors: Zhou; W.;Jin, K.;
      Pages: 6237 - 6244
      Abstract: The high-intensity laser power beaming (HILPB) system is one of the most promising system in the field of long-range wireless power transfer. In HILPB system, the high-power laser diode (LD) is employed for its excellent character of high efficiency, high reliability, and small size. Normally, LD can operate in two different driving modes: the continuous mode and the pulse mode. The injected current has a direct effect on the electro-optical conversion efficiency of LD. This paper centers around LD model and its current source driver. The conversion efficiencies of the two driving modes are evaluated by means of simulations and experiments. The experimental results are shown to verify the theoretical analysis.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Dynamic Modeling Based on Coupled Modes for Wireless Power Transfer
    • Authors: Li; H.;Wang, K.;Huang, L.;Chen, W.;Yang, X.;
      Pages: 6245 - 6253
      Abstract: A novel dynamic modeling method based on the concept of coupled modes is proposed for wireless power transfer (WPT) systems which use magnetic resonant coupling. The proposed method aims on the dynamics of the overall WPT system, including the nonlinear inverter and rectifier. It uses the slowly varying amplitudes and phases of coupled modes rather than resonant currents and voltages to describe the coupled resonances. Three analytical models—averaged model, small signal model, and conductance network model are developed sequentially by using the proposed method. The orders of the developed models are equal to or lower than that of the discrete state space model. In contrast, the existing dynamic modeling methods for WPT systems and resonant converters have to transform the discrete state space model into a higher order model or use complex currents and voltages in order to adopt the averaging method and obtain an analytical model. Simulation and experimental results give a firm support to the proposed method and models. The concept employed in this paper provides a deeper insight into the dynamic behaviors of coupled resonances.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Multiple-Inputs and Multiple-Outputs Wireless Power Combining and
           Delivering Systems
    • Authors: Nguyen; M.Q.;Chou, Y.;Plesa, D.;Rao, S.;Chiao, J.;
      Pages: 6254 - 6263
      Abstract: In this paper, we investigated the effect of power combining and delivering in multiinput and multioutput wireless energy transmission systems, which consist of more than one transmitter antennas as sources and more than one receiver antennas as loads and repeaters. Theoretical expressions were developed to model the system operation that can be in a large-scale wireless energy network architecture. System characteristics, such as power transfer between antennas, power losses induced in each antenna, wireless efficiency, coil misalignment, and power fluctuation due to the loss of frequency synchronization were examined by theory and verified with experiments. Measurement results matched well with the theory demonstrating the feasibility of combining and delivering power with high efficiencies in large-scale wireless energy transmission systems.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Compliance Testing Methodology for Wireless Power Transfer Systems
    • Authors: Nadakuduti; J.;Douglas, M.;Lu, L.;Christ, A.;Guckian, P.;Kuster, N.;
      Pages: 6264 - 6273
      Abstract: Wireless power transfer (WPT) systems have become popular, with applications in charging portable electronics via inductive coupling between a transmit and receive coil. Accurate estimation of the induced exposure is required as the incident magnetic fields near the coils often exceed the reference levels. Standardized procedures do not yet exist for the demonstration of compliance of these products with electromagnetic guidelines for human exposure. For this purpose, we propose a conservative methodology using simplified homogeneous phantoms. An approximation for the minimum compliance distance for user exposure is developed based on the theoretical evaluation of the induced fields and simulations of detailed anatomical models. The simulation results are experimentally validated for a practical WPT application at 6.78 MHz. Criteria for exclusion of WPT systems from compliance evaluation are presented as a function of coil dimensions, operating current and frequency.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Novel Phase-Control-Based Energy Beamforming Techniques in Nonradiative
           Wireless Power Transfer
    • Authors: Lim; Y.;Park, J.;
      Pages: 6274 - 6287
      Abstract: Recent efforts to increase the energy transfer efficiency in magnetic resonant coupling-based wireless power transfer (WPT) systems, have been focused on improving quality factor, precision of impedance matching, and position alignment between the resonators. Although those approaches are effective to increase transfer efficiencies, the transferred energy can easily be wasted due to leakage flux of nondirectional fields. In this paper, we present a novel magnetic field shaping technology for improving the energy efficiency in a near-field WPT system. In this study, the beamforming techniques that have been used for radio frequency systems are efficiently exploited in a WPT system to improve the transfer efficiencies by minimizing unnecessary leakage flux. The optimal antenna structure for energy forming is first determined through mathematical analysis. Using the proposed crossed antennas, the phase-control method is effectively used to form magnetic fields in particular directions. The proposed energy forming-based WPT system using crossed antennas is implemented with the phase control of three-power stack transmitters. The experimental results matches well with the theoretical analysis, and the energy-forming approach for synthesizing the magnetic fields achieves average improvements of the transfer efficiency and transfer distance of up to 20.1 % and 30 % , respectively, over the conventional nonradiative energy transfer approach at 1 m distance.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Novel Phase-Shift Control of Semibridgeless Active Rectifier for
           Wireless Power Transfer
    • Authors: Colak; K.;Asa, E.;Bojarski, M.;Czarkowski, D.;Onar, O.C.;
      Pages: 6288 - 6297
      Abstract: A novel phase-shift control of a semibridgeless active rectifier (S-BAR) is investigated in order to utilize the S-BAR in wireless energy transfer applications. The standard receiver-side rectifier topology is developed by replacing rectifier lower diodes with synchronous switches controlled by a phase-shifted PWM signal. Theoretical and simulation results show that with the proposed control technique, the output quantities can be regulated without communication between the receiver and transmitter. To confirm the performance of the proposed converter and control, experimental results are provided using 8-, 15-, and 23-cm air gap coreless transformer which has dimension of 76 cm × 76 cm, with 120-V input and the output power range of 0 to 1kW with a maximum efficiency of 94.4%.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Power Delivery and Leakage Field Control Using an Adaptive Phased Array
           Wireless Power System
    • Authors: Waters; B.H.;Mahoney, B.J.;Ranganathan, V.;Smith, J.R.;
      Pages: 6298 - 6309
      Abstract: Efficient wireless power transfer and precise control of power delivery and leakage field strength can be achieved using a phased array wireless power transfer system. This has particular importance for charging multiple devices simultaneously, or charging devices in environments where humans or foreign objects will be in close proximity. The phased array wireless power system consists of two or more phase-synchronized power amplifiers each driving a respective transmit coil. The system can maximize power delivery to an intended receiver in one location while simultaneously minimizing power delivery and leakage fields in other locations. These functions are possible by varying the amplitude and phase of each transmitter. This paper provides an analysis of a phased array wireless power transfer system using near-field magnetically coupled resonators, and derives parameters that can be used to automatically determine the optimal magnitude and phase of each transmitter to deliver power to one or more receivers. Experimental results verify the theoretical analysis and additional features of the full system are demonstrated.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • An Efficiency Optimization Scheme for Bidirectional Inductive Power
           Transfer Systems
    • Authors: Nguyen; B.X.;Vilathgamuwa, D.M.;Foo, G.H.B.;Wang, P.;Ong, A.;Madawala, U.K.;Nguyen, T.D.;
      Pages: 6310 - 6319
      Abstract: Unidirectional inductive power transfer systems allow loads to consume power, while bidirectional inductive power transfer (BIPT) systems are more suitable for loads requiring two-way power flow such as vehicle to grid applications with electric vehicles. Many attempts have been made to improve the performance of BIPT systems. In a typical BIPT system, the output power is controlled using the pickup converter phase shift angle, while the primary converter regulates the input current. This paper proposes an optimized phase-shift modulation strategy to minimize the coil losses of a series–series compensated BIPT system. In addition, a comprehensive study on the impact of power converters on the overall efficiency of the system is also presented. A closed-loop controller is proposed to optimize the overall efficiency of the BIPT system. Theoretical results are presented in comparison to both simulations and measurements of a 0.5 kW prototype to show the benefits of the proposed concept. Results convincingly demonstrate the applicability of the proposed system offering high efficiency over a wide range of output power.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Dual-Side Controlled Inductive Power Transfer System Optimized for Large
           Coupling Factor Variations and Partial Load
    • Authors: Diekhans; T.;De Doncker, R.W.;
      Pages: 6320 - 6328
      Abstract: In this study, a 3-kW inductive power transfer system is investigated, specifically intended for contactless vehicle charging. A series-series-compensated topology with dual-side power control and a corresponding control strategy is proposed to significantly increase the overall efficiency, especially for systems with large coupling factor variations and in partial load mode. The topology, which is closely related to the dual-active bridge converter, enables the dual-side power control without adding additional dc/dc converters to the system, and thus keeping the additional hardware effort minimal. A detailed analysis of the proposed topology is provided, and the benefits of the dual-side control are demonstrated both theoretically and experimentally. A hardware prototype is built and a peak dc-to-dc efficiency of 95.8% at 100 mm air gap and a minimal efficiency of 92.1% at 170 mm air gap is measured, including the power electronic components. The partial load efficiency at 500 W output power is still as high as 90.6% at 135 mm air gap. Overall, the proposed topology provides a practical method to overcome the main drawback of most single-side controlled inductive power transfer systems, which is a significant efficiency drop outside the nominal operating point.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Hybrid IPT Topologies With Constant Current or Constant Voltage Output for
           Battery Charging Applications
    • Authors: Qu; X.;Han, H.;Wong, S.;Tse, C.K.;Chen, W.;
      Pages: 6329 - 6337
      Abstract: The inductive power transfer (IPT) technique in battery charging applications has many advantages compared to conventional plug-in systems. Due to the dependencies on transformer characteristics, loading profile, and operating frequency of an IPT system, it is not a trivial design task to provide the battery the required constant charging current (CC) or constant battery charging voltage (CV) efficiently under the condition of a wide load range possibly defined by the charging profile. This paper analyzes four basic IPT circuits with series–series (SS), series–parallel (SP), parallel–series (PS), and parallel–parallel (PP) compensations systematically to identify conditions for realizing load-independent output current or voltage, as well as resistive input impedance. Specifically, one load-independent current output circuit and one load-independent voltage output circuit having the same transformer, compensating capacitors, and operating frequency can be readily combined into a hybrid topology with fewest additional switches to facilitate the transition from CC to CV. Finally, hybrid topologies using either SS and PS compensation or SP and PP compensation are proposed for battery charging. Fixed-frequency duty cycle control can be easily implemented for the converters.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Wireless Charging System Applying Phase-Shift and Amplitude Control to
           Maximize Efficiency and Extractable Power
    • Authors: Berger; A.;Agostinelli, M.;Vesti, S.;Oliver, J.A.;Cobos, J.A.;Huemer, M.;
      Pages: 6338 - 6348
      Abstract: Wireless power transfer (WPT) is an emerging technology with an increasing number of potential applications to transfer power from a transmitter to a mobile receiver over a relatively large air gap. However, its widespread application is hampered due to the relatively low efficiency of current Wireless power transfer (WPT) systems. This study presents a concept to maximize the efficiency as well as to increase the amount of extractable power of a WPT system operating in nonresonant operation. The proposed method is based on actively modifying the equivalent secondary-side load impedance by controlling the phase-shift of the active rectifier and its output voltage level. The presented hardware prototype represents a complete wireless charging system, including a dc–dc converter which is used to charge a battery at the output of the system. Experimental results are shown for the proposed concept in comparison to a conventional synchronous rectification approach. The presented optimization method clearly outperforms state-of-the-art solutions in terms of efficiency and extractable power.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Steady-State Load Identification Method of Inductive Power Transfer System
           Based on Switching Capacitors
    • Authors: Su; Y.;Zhang, H.;Wang, Z.;Patrick Hu, A.;Chen, L.;Sun, Y.;
      Pages: 6349 - 6355
      Abstract: An online steady-state load identification method is proposed to solve the problems related to frequency drift, system robustness deterioration, difficulties in controller design due to the uncertainties in load and mutual inductance variations of an inductive power transfer (IPT) system. Take a Series-Series-type IPT system as an example, an additional capacitor is added into the system to make the system work in two operating modes, and a mathematical model is established according to the two modes for the system identification. Simulation and experimental results have verified the proposed online load identification method. It has demonstrated that the method is accurate and reliable for identifying uncertain loads and magnetic coupling variations if other system parameters are known. The method can be used to improve the system performance with precise control.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Loosely Coupled Transformer Structure and Interoperability Study for EV
           Wireless Charging Systems
    • Authors: Zhang; W.;White, J.C.;Abraham, A.M.;Mi, C.C.;
      Pages: 6356 - 6367
      Abstract: As the wireless power transfer (WPT) technology has been proved to be a convenient and reliable charging method to plug-in hybrid electric vehicles and electric vehicles, the loosely coupled transformer structure and size are the primary and fundamental concern to design an efficient WPT system. In this paper, a double D (DD) coil and a unipolar coil are selected to conduct the study. We focus on the coil structure design to achieve the maximum coupling coefficient as well as efficiency with two situations: 1) with no misalignment, and 2) with a 75-mm door-to-door and 100-mm front-to-back misalignment at which the maximum operating capability can still be achieved. A coil size optimization process is proposed for both the DD coil and the unipolar coil configurations. The relationship between the size of the secondary (receiving) coil, which determines the weight of the pad on the vehicle, and achievable maximum efficiency is studied for both coil topologies. The interoperability between the two coil topologies is studied. The proposed transformer structures with aluminum shielding meet human exposure regulations of the International Commission on Non-Ionizing Radiation Protection guidelines as a foundation. Finally, experiments validated the analyses.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Economic Analysis of the Dynamic Charging Electric Vehicle
    • Authors: Jeong; S.;Jang, Y.J.;Kum, D.;
      Pages: 6368 - 6377
      Abstract: A wireless charging or inductive charging electric vehicle (EV) is a type of EVs with a battery that is charged from a charging infrastructure, using a wireless power transfer technology. Wireless charging EVs are classified as stationary or dynamic charging EVs. Stationary charging EVs charge wirelessly when they are parked, and dynamic charging EVs can charge while they are in motion. The online electric vehicle developed at the Korea Advanced Institute of Science and Technology is an example of a commercially available dynamic charging transportation system. Numerous studies have reported that one of the benefits of dynamic charging is that it allows smaller and lighter batteries to be used, due to frequent charging using the charging infrastructure embedded under roads. In this paper, we quantitatively analyze the benefits of dynamic charging with an economic model of battery size and charging infrastructure allocation, using a mathematical optimization model. Particularly, we analyze by how much battery size can be reduced and what the cost saving of reducing the battery size is with the model. We also show that the dynamic charging can be beneficial to battery life.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Design of a Universal Inductive Charger for Multiple Electric Vehicle
    • Authors: Liu; N.;Habetler, T.G.;
      Pages: 6378 - 6390
      Abstract: Inductive power transfer technology has become a popular solution for battery charging of electric vehicles (EVs). However, problems such as varied magnetic coupling caused by coil misalignment still limit its practical applications, by safety and stability issues. Meanwhile, the growing market of EVs asks for a universal charger for various models. This paper presents the design process of a universal inductive charger (UIC) for EVs. The proposed UIC is capable of adaptively providing a constant or controllable charging voltage to various EVs, with a wide range of varied magnetic coupling between the transmitting and receiving coils. With a series-connected LC circuit, zero-voltage switching of the primary dc–ac inverter is universally realized in every charging cycle. A simple yet effective control method based on the frequency variation is used to automatically select the optimal frequency in different coupling conditions and adjust the frequency during the charging process. The design of the charging interface is also optimized with higher efficiency and power-transfer capability. Simulations and prototypes validate that the proposed UIC is accurate, robust, and applicable.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Evaluation of Magnetic Pad Sizes and Topologies for Electric Vehicle
    • Authors: Lin; F.Y.;Covic, G.A.;Boys, J.T.;
      Pages: 6391 - 6407
      Abstract: Inductive power transfer is becoming increasingly popular in stationary electric vehicle charging systems due to improved designs. However, such optimizations are normally performed for matched topologies which are similarly sized, over constant air gaps and without significant misalignment. In a real situation where the primary and secondary pads may not be matched and may be misaligned, pad designs must take into consideration coupling factors, leakage fluxes, pad quality factors, reflected impedance, and size. This paper analyzes the effects which variations in pad sizes, topologies, and displacements in three dimensions has on these parameters. It was found that solenoid pads should not be used as a primary pad due to high leakage fluxes, low native quality factors, and the fact that they are not fully interoperable over the whole desired range of use. Bipolar pad primaries are able to couple to any secondary pad over the entire range of use required and tend to have high native quality factors. Nonpolarized pads tend to have the lowest leakage fluxes but also low coupling. Suggestions on techniques to optimize these pads have also been included.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • A Comparative Study of Power Supply Architectures in Wireless EV Charging
    • Authors: Esteban; B.;Sid-Ahmed, M.;Kar, N.C.;
      Pages: 6408 - 6422
      Abstract: This paper examines two of the primary power supply architectures being predominantly used for wireless electric vehicle (EV) charging, namely the series LC (SLC) resonant and the hybrid series–parallel (LCL) resonant full-bridge inverter topologies. The study of both of these topologies is presented in the context of designing a 3-kW primary-side controlled stationary wireless EV charger with nominal operating parameters of 30-kHz center frequency, a range of coupling in the neighborhood of 0.18–0.26, and a parallel secondary pick-up with partial series coil compensation. A comparison of both architectures is made in terms of their design methodology, physical size, cost, complexity, and efficiency. It is found that the SLC architecture is 2.45% less costly than the LCL topology. On the other hand, it is observed that the LCL architecture achieves almost 10% higher peak efficiency at rated load and minimum coupling. The study also showed that the SLC topology suffers from poor light load efficiency, while the LCL topology maintains very high efficiency over its full range of coupling and loading. The study also revealed that the capacitor voltage stress is significantly higher in the SLC topology. Finally, it is also shown that the control complexity of the SLC architecture is higher than that of the LCL architecture because of its sensitivity to changes in the reflected secondary impedance, which result in loss of constant current source and ZVS operation unless a suitable combination of parameters are modulated by the closed-loop controller.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Integration of Inductively Coupled Power Transfer and Hybrid Energy
           Storage System: A Multiport Power Electronics Interface for
           Battery-Powered Electric Vehicles
    • Authors: McDonough; M.;
      Pages: 6423 - 6433
      Abstract: Detailed in this paper is a multiport power electronics interface which serves as an energy router for on-board electric and plug-in hybrid electric vehicles with inductively coupled power transfer (ICPT) and hybrid energy storage systems (HESS). The existing body of literature on HESSs lacks a unified controller and modular, flexible structure as well as integration of ICPT. In battery/ultracapacitor systems, this leads to piece-meal control of sources resulting in battery currents which are not fully decoupled from high-frequency/high-magnitude current and ultra-capacitor (UC) state of charge (SoC) not being properly controlled. A central controller is proposed in this paper which completely decouples the battery from both high-frequency and high-magnitude current, controls the SoC of the UCs, and models the SoC of the UCs in the stability analysis of the system. This system is particularly useful for online charging of HEVs in highway-type applications where ICPT pulse charging will be present. Solving the challenges of pulse charging will bring ICPT technology one step closer to widespread integration which has the potential to greatly reduce societies’ dependence on fossil fuel. Simulation and experimental results verify the feasibility of the proposed techniques.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Generalized Models on Self-Decoupled Dual Pick-up Coils for Large Lateral
    • Authors: Choi; S.Y.;Jeong, S.Y.;Lee, E.S.;Gu, B.W.;Lee, S.W.;Rim, C.T.;
      Pages: 6434 - 6445
      Abstract: Self-decoupled dual pick-up coils for large lateral tolerance and low electromagnetic field for pedestrians are proposed. Analytical models are developed that are applicable to any self-decoupled coils, regardless the coil types such as single/dual pick-ups and core/coreless coils. An optimum decoupling distance between adjacent pick-up coils is determined and found to be independent of the existence of a core plate. Maximum load power over a large lateral tolerance is obtained for the optimum decoupling distance. The proposed models are so general that they can be applied to any self-decoupled pick-up coils for stationary charging and dynamic charging systems. Moreover, the self-decoupled coils are compatible with any compensation method such as serial, parallel, and serial–parallel. A prototype system of 1.5 kW and Q = 60 for roadway powered electrical vehicles was implemented and showed fairly good agreements with the theoretical models and simulations. The measured lateral tolerance was 90 cm, which is about 1.5 times of the coil width.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Uniform Power I-Type Inductive Power Transfer System With
           DQ-Power Supply Rails for On-Line Electric Vehicles
    • Authors: Park; C.;Lee, S.;Jeong, S.Y.;Cho, G.;Rim, C.T.;
      Pages: 6446 - 6455
      Abstract: A narrow-width power-invariant inductive power transfer system (IPTS) along the driving direction is newly proposed in this paper. The conventional I-type power supply rail for on-line electric vehicles (OLEVs) has a very narrow power supply rail with 10-cm width and exposes pedestrians to a very low electromagnetic field due to its alternatively arranged magnetic poles along the driving direction of electric vehicles; however, it has a major drawback: Sinusoidal variation of the induced pick-up voltage depending on pick-up positions on the power supply rail along driving direction. To overcome this disadvantage, a dq-power supply rail fed by two high-frequency ac currents of the d-phase and q-phase is introduced in this paper. The d -phase and q-phase magnetic poles are alternatively arranged in a line; hence, the induced voltage of a pickup becomes spatially uniform. The power invariant characteristic of the proposed IPTS for OLEV has been verified by analysis, simulations, and experiments. A practical winding method is suggested as well.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
  • Ultraslim S-Type Power Supply Rails for Roadway-Powered Electric Vehicles
           Generalized Models on Self-Decoupled Dual Pick-Up Coils for a Large
           Lateral Tolerance
    • Authors: Choi; S.Y.;Jeong, S.Y.;Gu, B.W.;Lim, G.C.;Rim, C.T.;
      Pages: 6456 - 6468
      Abstract: An ultraslim S-type power supply rail, which has a width of only 4 cm, for roadway-powered electric vehicles (RPEVs) is proposed in this paper. The cross section of the core has a thin S-shape, and a vertically-wound multiturn coil is displaced inside the core. In this way, the most slim power supply rail is designed, which is crucial for the commercialization of RPEVs. The construction of roadway infrastructure, which is responsible for more than 80% of the total deployment cost for RPEVs, can be much easier when the width of the power supply rail is so small. To increase portability and to minimize construction time, a foldable power supply module is also proposed in which flexible power cables connect each foldable power supply module such that no connectors are needed during deployment. An effective winding method for minimizing the cable length is proposed, and an optimum core thickness of the proposed power supply rail is determined by FEA simulations and verified by a prototype power supply module. By virtue of the ultraslim shape, a large lateral displacement of 30 cm at an air gap of 20 cm was experimentally obtained, which is 6 cm larger than that of the I-type power supply rail. In addition to the larger lateral displacement, it is estimated that the S-type one has lower EMF than the I-type one because the width of the S-type one is narrower than that of I-type one. The maximum efficiency, excluding the inverter, was 91%, and the pick-up power was 22 kW.
      PubDate: Nov. 2015
      Issue No: Vol. 30, No. 11 (2015)
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