The Experts below are selected from a list of 36891 Experts worldwide ranked by ideXlab platform

Fang Zheng Peng - One of the best experts on this subject based on the ideXlab platform.

  • sic based z source resonant converter with constant frequency and Load Regulation for ev wireless charger
    IEEE Transactions on Power Electronics, 2017
    Co-Authors: Hulong Zeng, Fang Zheng Peng
    Abstract:

    Traditional Load Regulation methods for a resonant converter mainly rely on frequency modulation. It is always a tradeoff between the design of the resonant network and the range of Load. Especially for wireless power transfer (WPT) systems, the resonant network usually has a high quality factor. Small variation on frequency leads to huge drop in gain and efficiency. Due to this problem, many WPT systems are unregulated and they need one or two more front-end stages to regulate the dc bus voltage and perform power factor correction (PFC). In order to lower the cost and complexity of two- or three-stages structure, a single-stage solution with a silicon carbide (SiC) based Z-source resonant converter (ZSRC) was recently proposed. The Z-source network provides high reliability as being immune to shoot-through problems. Additionally, a ZSRC can boost the dc bus voltage while the traditional voltage-source inverter can only produce a lower voltage. However, the Load Regulation of this new topology has not been addressed. Two effective Load Regulation methods with constant frequency are presented for this SiC-based ZSRC specifically. Operation principle of the two Load Regulation methods are described in this paper. Experimental results based on a 200-W scale-down prototype with a full-bridge series resonant dc–dc converter are presented to illustrate the mechanism of these two methods.

  • harmonic burst control strategy for full bridge series resonant converter based ev charging
    IEEE Transactions on Power Electronics, 2017
    Co-Authors: Hulong Zeng, Nomar S Gonzalezsantini, Shuitao Yang, Fang Zheng Peng
    Abstract:

    An effective output voltage Regulation method using harmonic burst control is presented. This method can greatly improve operating performance of the full-bridge series-resonant dc-dc converter (SRC) applied to electric vehicle (EV) battery charging. The proposed harmonic burst control not only provides Load Regulation, but it also achieves soft switching at both turn-ons and turn-offs under all Load conditions. As a result, it improves the system efficiency over 10% for light-Load conditions without any extra hardware, compared to that of the traditional frequency modulation method. Moreover, it has much smaller pulsed power over a wide range Load compared to the traditional bang-bang burst control. Theoretical analysis of the series-resonant circuit and power loss analysis are discussed in detail in this paper. Experimental results based on a 1-kW prototype with 20-cm air gap between the primary and secondary sides of the series-resonant converter are presented to demonstrate the effectiveness of the proposed control strategy.

  • a review of galvanically isolated impedance source dc dc converters
    IEEE Transactions on Power Electronics, 2016
    Co-Authors: Andrii Chub, Dmitri Vinnikov, Frede Blaabjerg, Fang Zheng Peng
    Abstract:

    Impedance-source converters, an emerging technology in electric energy conversion, overcome limitations of conventional solutions by the use of specific impedance-source networks. Focus of this paper is on the topologies of galvanically isolated impedance-source dc–dc converters. These converters are particularly appropriate for distributed generation systems with renewable or alternative energy sources, which require input voltage and Load Regulation in a wide range. We review here the basic topologies for researchers and engineers, and classify all the topologies of the impedance-source galvanically isolated dc–dc converters according to the element that transfers energy from the input to the output: a transformer, a coupled inductor, or their combination. This classification reveals advantages and disadvantages, as well as a wide space for further research. This paper also outlines the most promising research directions in this field.

Roger J King - One of the best experts on this subject based on the ideXlab platform.

  • high performance ripple feedback for the buck unity power factor rectifier
    IEEE Transactions on Power Electronics, 1995
    Co-Authors: Roger J King
    Abstract:

    The buck unity-power-factor rectifier has harmonic-free input current with complete Load Regulation down to zero output voltage. A new "nonlinear ripple feedback" is proposed which exactly cancels the spoiling effect of DC-side current ripple on the low-distortion AC line current waveforms, even for large amounts of ripple. This cancellation is independent of operating point and readily implemented with analog hardware, thereby permitting economies in the design of the DC filter while maintaining harmonic-free operation. Both large-signal and incremental analyses of the rectifier are given. Confirming experimental results from a 1 kW 48 V isolated battery charger operating with current-ripple levels ranging from 50% to discontinuous-conduction-mode operation are given. >

  • high performance ripple feedback for the buck unity power factor rectifier
    Conference of the Industrial Electronics Society, 1993
    Co-Authors: Roger J King
    Abstract:

    The buck unity power factor rectifier has harmonic-free input current with complete Load Regulation down to zero output voltage. A new "nonlinear ripple feedback" is proposed which exactly cancels the spoiling effect of DC-side current ripple on the low-distortion AC line current waveforms, even for large amounts of ripple. This cancellation is independent of operating point and readily implemented with analog hardware, thereby permitting economies in the design of the DC filter while maintaining harmonic-free operation. Both large-signal and incremental analyses of the rectifier are given. Confirming experimental results from a 1 kW 48 V isolated battery charger operating with current-ripple levels ranging from 50 percent to discontinuous-conduction-mode operation are given. >

Shekhar Borkar - One of the best experts on this subject based on the ideXlab platform.

  • area efficient linear regulator with ultra fast Load Regulation
    Symposium on VLSI Circuits, 2005
    Co-Authors: B A Bloechel, C Parsons, D Finan, Shekhar Borkar
    Abstract:

    We demonstrate a fully integrated linear regulator for multisupply voltage microprocessors implemented in a 90 nm CMOS technology. Ultra-fast single-stage Load Regulation achieves a 0.54-ns response time at 94% current efficiency. For a 1.2-V input voltage and 0.9-V output voltage the regulator enables a 90 mVp-p output droop for a 100-mA Load step with only a small on-chip decoupling capacitor of 0.6 nF. By using a PMOS pull-up transistor in the output stage we achieved a small regulator area of 0.008 mm 2 and a minimum dropout voltage of 0.2 V for 100 mA of output current. The area for the 0.6-nF MOS capacitor is 0.090 mm 2 .

  • an area efficient integrated linear regulator with ultra fast Load Regulation
    Symposium on VLSI Circuits, 2004
    Co-Authors: B A Bloechel, C Parsons, D Finan, Shekhar Borkar
    Abstract:

    We demonstrate a fully-integrated linear regulator for multi-supply-voltage microprocessors implemented in a 90 nm CMOS technology. Ultra-fast, single-stage Load Regulation achieves 0.54 ns response time at 94% current efficiency. This enables 10% peak-to-peak output noise for a 100 mA Load step with only a small on-chip decoupling capacitor of 0.6 nF. A PMOS pull-up transistor in the output stage results in a small regulator area of 0.008 mm/sup 2/ and the 0.6 nF MOS capacitor area of 0.090 mm/sup 2/.

Rahim Tafazolli - One of the best experts on this subject based on the ideXlab platform.

  • throughput analysis and user barring design for uplink noma enabled random access
    arXiv: Signal Processing, 2020
    Co-Authors: Chuan Heng Foh, Atta Ul Quddus, Yuanwei Liu, Rahim Tafazolli
    Abstract:

    Being able to accommodate multiple simultaneous transmissions on a single channel, non-orthogonal multiple access (NOMA) appears as an attractive solution to support massive machine type communication (mMTC) that faces a massive number of devices competing to access the limited number of shared radio resources. In this paper, we first analytically study the throughput performance of NOMA-based random access (RA), namely NOMA-RA. We show that while increasing the number of power levels in NOMA-RA leads to a further gain in maximum throughput, the growth of throughput gain is slower than linear. This is due to the higher-power dominance characteristic in power-domain NOMA known in the literature. We explicitly quantify the throughput gain for the very first time in this paper. With our analytical model, we verify the performance advantage of the proposed NOMA-RA scheme by comparing with the baseline multi-channel slotted ALOHA (MS-ALOHA), with and without capture effect. Despite the higher-power dominance effect, the maximum throughput of NOMA-RA with four power levels achieves over three times that of the MS-ALOHA. However, our analytical results also reveal the sensitivity of Load on the throughput of NOMA-RA. To cope with the potential bursty traffic in mMTC scenarios, we propose adaptive Load Regulation through a practical user barring algorithm. By estimating the current Load based on the observable channel feedback, the algorithm adaptively controls user access to maintain the optimal Loading of channels to achieve maximum throughput. When the proposed user barring algorithm is applied, simulations demonstrate that the instantaneous throughput of NOMA-RA always remains close to the maximum throughput confirming the effectiveness of our Load Regulation.

Gun-woo Moon - One of the best experts on this subject based on the ideXlab platform.

  • improving the light Load Regulation capability of llc series resonant converter using impedance analysis
    IEEE Transactions on Power Electronics, 2017
    Co-Authors: Cheol-o Yeon, Moo-hyun Park, Gun-woo Moon
    Abstract:

    Generally, an LLC series resonant converter ( LLC SRC) is an attractive topology for applications, which require wide input variation and high conversion efficiency because of its wide gain capability and soft-switching capability. However, there is a Regulation problem in which the output voltage increases as the Load current decreases. In this paper, Bode plot and impedance asymptote analysis were conducted to obtain an intuitive sense of the Regulation characteristic of LLC SRC under the light-Load condition. Moreover, to improve the Regulation capability, a new resonant tank with an additional capacitor is proposed. Its design guidelines were determined by Bode plot and impedance asymptote analysis. Therefore, the proposed LLC SRC achieves very light Load Regulation, while it maintains the advantages of typical LLC SRCs.

  • Bode plot and impedance asymptotes for light-Load Regulation of LLC series resonant converter
    2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia), 2016
    Co-Authors: Cheol-o Yeon, Jong Woo Kim, Moo-hyun Park, Yujin Jang, Cheon-yong Lim, Gun-woo Moon
    Abstract:

    In general, the LLC series resonant converter (LLC SRC) is an attractive topology for the applications which require the wide input variation and high efficiency especially at light Load condition. This is because of its wide gain capability with pulse-frequency modulation and zero-voltage-switching over the entire Load condition. However, there is a Regulation problem that the output voltage increases as the output current decreases. In this paper, Bode plot and impedance asymptotes analyses have been conducted to obtain an intuitive sense for the Regulation characteristic of LLC SRC under light-Load condition. Moreover, in order to improve the Regulation characteristic, a new resonant tank with an additional capacitor is proposed and its design guideline is also provided by Bode plot and impedance asymptotes analyses. Therefore, the proposed LLC SRC achieves the very light-Load Regulation while it can maintain the advantages of typical LLC SRC.