The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Chun T. Rim - One of the best experts on this subject based on the ideXlab platform.
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Self-Inductance-Based Metal Object Detection With Mistuned Resonant Circuits and Nullifying Induced Voltage for Wireless EV Chargers
IEEE Transactions on Power Electronics, 2019Co-Authors: Seog Y. Jeong, Van X. Thai, Jun H. Park, Chun T. RimAbstract:In this paper, a metal object detection (MOD) system, a kind of foreign object detection (FOD), which is based on mistuned Resonant Circuits and utilizes the variation of self-inductance of a sensing pattern, is newly proposed for wireless electric vehicle (EV) chargers. The sensing pattern that consists of multiple loop coil sets is mounted on the transmitting (Tx) pad of an EV charger, where a loop coil set has two coils connected in series with the opposite polarity to cancel out the induced voltage generated by the Tx coil. Variation of self-inductance of the loop coil set is detected by a parallel-Resonant circuit, driven by a current source and operating at near 1 MHz, in order to enhance the resolution of the proposed MOD system. To increase the detection sensitivity of the proposed MOD system, instead of an exact Resonant frequency, a mistuned operating frequency near the –3 dB point is utilized for the parallel-Resonant circuit. In this way, the proposed MOD system can detect very small metal objects regardless of their position and orientation on the Tx coil without any blind zone. Through simulations and experiments, it is found that the proposed MOD system detects not only horizontal but also standing upright metal objects. A prototype MOD system, operating at 85 kHz to satisfy the standard J2954, was fabricated to verify its feasibility. The results showed that output voltage change of the proposed MOD system becomes 22.7% for a piece of the aluminum foil of 3 × 3 cm2 and 40.9% for 100 Korean Won coin.
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metal object detection system with parallel mistuned Resonant Circuits and nullifying induced voltage for wireless ev chargers
2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia), 2018Co-Authors: Seog Y. Jeong, Jun H. Park, Van X Thai, Chun T. RimAbstract:In this paper, a metal object detection (MOD) system, a kind of foreign object detection (FOD), which is based on mistuned Resonant Circuits and utilizes variation of self-inductance of a sensing pattern, is newly proposed for wireless electric vehicle (EV) chargers. The sensing pattern that consists of multiple loop coil sets is mounted on the transmitting (Tx) pad of an EV charger, where a loop coil set has two coils connected in series with opposite polarity to cancel out the induced voltage generated by the Tx coil. Variation of self-inductance of the loop coil set is detected by a parallel-Resonant circuit, driven by a current source and operating at near 1 MHz. To increase the detection sensitivity of the proposed MOD system, instead of an exact Resonant frequency, a mistuned operating frequency near the −3dB point is utilized for the parallel-Resonant circuit. Through simulations and experiments, it is found that the proposed MOD system detects not only horizontal but also standing upright metal objects. A prototype MOD system, operating at 85 kHz to satisfy the standard J2954, was fabricated to verify its feasibility. The results showed that output voltage change of the proposed MOD system becomes 22.7 % for a piece of aluminum foil of 3 × 3 cm2 and 40.9 % for 100 Korean Won coin, respectively.
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gyrator based analysis of Resonant Circuits in inductive power transfer systems
IEEE Transactions on Power Electronics, 2016Co-Authors: Yeong H Sohn, Bo H Choi, Gyuhyeong Cho, Chun T. RimAbstract:In this paper, first, it is found that not only the magnetically coupled inductors but also all inductive power transfer systems (IPTSs) inherently have the nature of a gyrator. Widely known characteristics of IPTSs such as impedance inversion and source-type conversion are proved to be the nature of the gyrator. A graphical approach that utilizes the gyrator is proposed for the modeling of IPTSs in general. The proposed graphical technique enables manipulations on the circuit diagram instead of on the circuit equations, which are difficult to handle when the system order is higher than 4. Hence, the equivalent model can be obtained almost by inspection conveniently, giving fruitful physical insights that are limitedly achieved with the equation manipulations. Steady-state analyses at any frequency are possible, and equivalent series resistances can also be included in the proposed model. Five selected electrical characteristics, i.e., source-to-load gain, load-independent output voltage/current characteristics, power factor at the source, sign of the source phase angle, and allowances of open/short loads are evaluated for three widely used IPTS topologies. Also, this technique is extended to the mistuned case for verifying the general use of the approach. An experimental prototype of the voltage-source-type inductor–capacitor–inductor secondary-parallel (V-LCL-P) topology was built to demonstrate the proposed approach for both perfectly tuned and mistuned situations at 85 W and 100 kHz.
K W E Cheng - One of the best experts on this subject based on the ideXlab platform.
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a flexible load independent multi output wireless power transfer system based on cascaded double t Resonant Circuits analysis design and experimental verification
IEEE Transactions on Circuits and Systems I-regular Papers, 2019Co-Authors: K W E ChengAbstract:There are practical applications requiring the wireless power transfer (WPT) system to supply multiple output voltages to a variety of loads. In this paper, in order to achieve this goal, multiple double T Resonant Circuits are connected to the common port of the receiver side. Based on the modeling and analysis of the double T Resonant circuit, it is found that the load-independent output and input zero phase angle (ZPA) can be derived. The proposed WPT system presents the following merits: 1) output voltages are load independent and can be controlled synchronously against the disturbance from input DC source and mutual coupling by using only one closed loop; 2) the output voltages can be adjusted individually to different levels by configuring circuit parameters; 3) only passive components are used to achieve multiple outputs. The power loss can be reduced due to the parasitic resistance of the passive component is very small and can be negligible; and 4) the reactive power losses are minimized due to the input ZPA of the system. An experimental prototype with two output channels is built, based on which the load independent and the controllable characteristics of the output voltages are verified.
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unified analysis of switched capacitor Resonant converters
IEEE Transactions on Industrial Electronics, 2004Co-Authors: Y P B Yeung, K W E Cheng, K K Law, D SutantoAbstract:A family of switched-capacitor Resonant Circuits using only two transistors is presented. The circuit operates under zero-current switching and, therefore, the switching loss is zero. It also offers a wide choice of voltage conversions including fractional as well as multiple and inverted voltage conversion ratios.
Christopher H. T. Lee - One of the best experts on this subject based on the ideXlab platform.
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An Overview of Resonant Circuits for Wireless Power Transfer
Energies, 2017Co-Authors: Chaoqiang Jiang, K. T. Chau, Chunhua Liu, Christopher H. T. LeeAbstract:With ever-increasing concerns for the safety and convenience of the power supply, there is a fast growing interest in wireless power transfer (WPT) for industrial devices, consumer electronics, and electric vehicles (EVs). As the Resonant circuit is one of the cores of both the near-field and far-field WPT systems, it is a pressing need for researchers to develop a high-efficiency high-frequency Resonant circuit, especially for the mid-range near-field WPT system. In this paper, an overview of Resonant Circuits for the near-field WPT system is presented, with emphasis on the non-Resonant converters with a Resonant tank and Resonant inverters with a Resonant tank as well as compensation networks and selective Resonant Circuits. Moreover, some key issues including the zero-voltage switching, zero-voltage derivative switching and total harmonic distortion are addressed. With the increasing usage of wireless charging for EVs, bidirectional Resonant inverters for WPT based vehicle-to-grid systems are elaborated.
Peter Adam Hoeher - One of the best experts on this subject based on the ideXlab platform.
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fsk based simultaneous wireless information and power transfer in inductively coupled Resonant Circuits exploiting frequency splitting
IEEE Access, 2019Co-Authors: Peter Adam HoeherAbstract:Inductively coupled Resonant Circuits are affected by the so-called frequency splitting phenomenon at short distances. In the area of power electronics, tracking one of the peak frequencies is state-of-the-art. In the data transmission community, however, the frequency splitting effect is often ignored. Particularly, modulation schemes have not yet been adapted to the bifurcation phenomenon. We argue that binary frequency shift keying (2-ary FSK) is a low-cost modulation scheme which well matches the double-peak voltage transfer function $H(s)$ , particularly when the quality factor $Q$ is large, whereas most other modulation schemes suffer from the small bandwidths of the peaks. Additionally, we show that a rectified version of 2-ary FSK coined rectified FSK (RFSK), is even more attractive from output power and implementation points of view. The analytical and numerical contributions include the efficiency factor, the impulse response, and the bit error performance. A low-cost noncoherent receiver is proposed. The theoretical examinations are supported by an experimental prototype.
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fsk based simultaneous wireless information and power transfer in inductively coupled Resonant Circuits exploiting frequency splitting
arXiv: Signal Processing, 2019Co-Authors: Peter Adam HoeherAbstract:Inductively coupled Resonant Circuits are affected by the so-called frequency splitting phenomenon at short distances. In the area of power electronics, tracking of one of the peak frequencies is state-of-the-art. In the data transmission community, however, the frequency splitting effect is often ignored. Particularly, modulation schemes have not yet been adapted to the bifurcation phenomenon. We argue that binary frequency shift keying (2-ary FSK) is a low-cost modulation scheme which well matches the double-peak voltage transfer function $H(s)$, particularly when the quality factor $Q$ is large, whereas most other modulation schemes suffer from the small bandwidths of the peaks. Additionally we show that a rectified version of 2-ary FSK, coined rectified FSK (RFSK), is even more attractive from output power and implementation points of view. Analytical and numerical contributions include the efficiency factor, the impulse response, and the bit error performance. A low-cost incoherent receiver is proposed. Theoretical examinations are supported by an experimental prototype.
Raymond W Simmonds - One of the best experts on this subject based on the ideXlab platform.
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low loss superconducting Resonant Circuits using vacuum gap based microwave components
arXiv: Mesoscale and Nanoscale Physics, 2009Co-Authors: Katarina Cicak, Michael S Allman, J A Strong, Fabio Altomare, A J Sirois, Jed D Whittaker, John Teufel, Raymond W SimmondsAbstract:We have produced high-quality complex microwave Circuits, such as multiplexed resonators and superconducting phase qubits, using a "vacuum-gap" technology that eliminates lossy dielectric materials. We have improved our design and fabrication strategy beyond our earlier work, leading to increased yield, enabling the realization of these complex Circuits. We incorporate both novel vacuum-gap wiring crossovers (VGX) for gradiometric inductors and vacuum-gap capacitors(VGC) on chip to produce Resonant Circuits that have large internal quality factors (30,000
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vacuum gap capacitors for low loss superconducting Resonant Circuits
IEEE Transactions on Applied Superconductivity, 2009Co-Authors: Katarina Cicak, Michael S Allman, J A Strong, K D Osborn, Raymond W SimmondsAbstract:Low-loss microwave components are used in many superconducting Resonant Circuits from multiplexed readouts of low-temperature detector arrays to quantum bits. Two-level system defects in amorphous dielectric materials cause excess energy loss. In an effort to improve capacitor components, we have used optical lithography and micromachining techniques to develop superconducting parallel-plate capacitors in which lossy dielectrics are replaced by vacuum gaps. Resonance measurements at 50 mK on lumped LC Circuits that incorporate these vacuum-gap capacitors (VGCs) reveal loss tangents at low powers as low as 4 times 10-5, significantly lower than with capacitors using amorphous dielectrics. VGCs are structurally robust, small, and easily scaled to capacitance values above 100 pF.
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vacuum gap capacitors for low loss superconducting Resonant Circuits
arXiv: Superconductivity, 2008Co-Authors: Katarina Cicak, Michael S Allman, J A Strong, K D Osborn, Raymond W SimmondsAbstract:Low-loss microwave components are used in many superconducting Resonant Circuits from multiplexed readouts of low-temperature detector arrays to quantum bits. Two-level system defects in amorphous dielectric materials cause excess energy loss. In an effort to improve capacitor components, we have used optical lithography and micromachining techniques to develop superconducting parallel-plate capacitors in which lossy dielectrics are replaced by vacuum gaps. Resonance measurements at 50 mK on lumped LC Circuits that incorporate these vacuum-gap capacitors (VGCs) reveal loss tangents at low powers as low as 4x10^{-5}, significantly lower than with capacitors using amorphous dielectrics. VGCs are structurally robust, small, and easily scaled to capacitance values above 100 pF.
