K.M. Smedley

University of California, Irvine, Irvine, California, United States

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Publications (176)332.46 Total impact

  • Source
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    ABSTRACT: Diversity of software packages to simulate the power system circuits is considerable. It is challenging to transfer power system circuit model data (PSCMD) among different software tools and rebuild the same circuit in the second software environment. This paper proposes a unified platform (UP) where PSCMD are stored in a spreadsheet file with a defined format. Script-based PSCMD transfer applications, written in MATLAB, have been developed for a set of software to read the circuit model data from the UP spreadsheet and reconstruct the circuit in the destination software. This significantly eases the process of transferring circuit model data between each pair of software tools. In this paper ETAP, OpenDSS, Grid LabD, and DEW are considered. In order to test the developed PSCMD transfer applications, circuit model data of a test circuit and an actual sample circuit from a Californian utility company, both built in CYME, were exported into the spreadsheet file according to the UP format. Thereafter, circuit model data were imported successfully from the spreadsheet files into all above mentioned software using the PSCMD transfer applications developed for each software individually. Finally, load flow analysis is performed in all software and the obtained results match with each other.
  • Alexander Abramovitz, Jia Yao, Keyue Smedley
    IEEE Transactions on Power Electronics 01/2015; DOI:10.1109/TPEL.2015.2424255 · 5.73 Impact Factor
  • Jia Yao, Alexander Abramovitz, Keyue Ma Smedley
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    ABSTRACT: This paper introduces a SEPIC-derived converter suited for alternative energy generation applications. The proposed converter utilizes tapped inductor and charge pump techniques to achieve high step-up gain and a passive regenerative snubber to attain high efficiency. Compared with earlier counterparts, the proposed converter has the advantage of continuous input current, which can be helpful in attaining accurate tracking of maximum power point of solar panels. The paper presents principle of operation, theoretical analysis, and design guidelines. Theoretical expectations were confirmed by simulation and experimental results.
    IEEE Transactions on Power Electronics 01/2015; 30(10):5565-5580. DOI:10.1109/TPEL.2014.2374992 · 5.73 Impact Factor
  • Bin Wu, Shouxiang Li, Keyue Ma Smedley, Sigmond Singer
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    ABSTRACT: A family of “Two-Switch Boosting Switched-Capacitor Converters (TBSC)” is introduced, which distinguishes itself from the prior arts by symmetrically interleaved operation, reduced output ripple, low yet even voltage stress on components, and systematic expandability. Along with the topologies, a modeling method is formulated, which provokes the converter regulation method through duty cycle and frequency adjustment. In addition, the paper also provides guidance for circuit components and parameter selection. A 1-kW 3X TBSC was built to demonstrate the converter feasibility, regulation capability via duty cycle and frequency, which achieved a peak efficiency of 97.5% at the rated power.
    IEEE Transactions on Power Electronics 01/2015; 30(10):5413-5424. DOI:10.1109/TPEL.2014.2375311 · 5.73 Impact Factor
  • Jia Yao, Alexander Abramovitz, Keyue Smedley
    IEEE Transactions on Power Electronics 01/2015; DOI:10.1109/TPEL.2015.2395455 · 5.73 Impact Factor
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    ABSTRACT: An energy regenerative passive snubber for transformer isolated converters is proposed. The snubber is implemented on the transformer's primary and secondary windings. The proposed snubber significantly reduces the voltage spike across the switch caused by the transformer's primary inductance upon switch turn-off and facilitates the fast ramping up of the transformer secondary current. In addition, the proposed snubber provides lossless zero voltage turn off and zero current turn on conditions for the power switch. Experimental example of a flyback converter has shown measured efficiency exceeding 90%. This paper describes the principle of operation and presents approximate theoretical analysis and design guidelines of the proposed snubber. Simulation and experimental results are also reported. The proposed energy regenerating snubber is best suited for flyback and SEPIC converters and can also be adapted to other transformer isolated topologies.
    IEEE Transactions on Power Electronics 11/2014; 29(11):6030-6040. DOI:10.1109/TPEL.2014.2301194 · 5.73 Impact Factor
  • Alexander Abramovitz, Jia Yao, Keyue Smedley
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    ABSTRACT: A family of single-switch SEPIC-derived converters, which apply a tapped inductor (TI), a charge pump (CP) and an inductorless regenerative snubber to attain a high DC step-up at high efficiency is introduced. The proposed converter family has the advantage of continuous input current, which can be helpful in attaining accurate tracking of the maximum power point of solar panels. The feasibility of the proposed topology is verified by simulation and experimental results.
    Electronics Letters 10/2014; 50(22):1626-1628. DOI:10.1049/el.2014.2190 · 1.07 Impact Factor
  • Marco Tedde, Keyue Smedley
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    ABSTRACT: An active anti-islanding method for three-phase grid-tied inverters is proposed in this paper. The method is based on asymmetric injection of the converter currents at a sub-harmonic frequency. This method allows an accurate detection of the islanding condition, thus it minimize the perturbation to the power system. The theoretical analysis have been confirmed by simulation and by experimental tests conducted on a 40kW One-Cycle Control grid tied inverter according to the test procedure outlined in the standard IEEE Std. 1547. The experiments have demonstrated negligible perturbation to the power system, with an increase in the THD of the current of less than 0.1% at full load.
    IEEE Transactions on Power Electronics 07/2014; PP(99):1-1. DOI:10.1109/TPEL.2013.2278792 · 5.73 Impact Factor
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    ABSTRACT: This paper evaluates the performance of magnetic amplifier regulator in isolated off-line power supplies with power factor correction stage. Simplified controller circuitry is suggested and analyzed. Experimental results are reported.
    2014 ELEKTRO; 05/2014
  • In Wha Jeong, Bum Seok Suh, Keyue Smedley
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    ABSTRACT: This paper proposes a new 1200V cascaded high voltage IC (HVIC) gate drive circuit for a three-level NPC inverter intelligent power module (IPM). The proposed single-ground IGBT gate driver of the 1200V three-level NPC inverter is based on a bootstrap capacitor charging method and a cascaded 600V HVIC configuration which can dramatically improve its integration for practical use, especially system air conditioner application. The proposed approach possibly enables high-volume production, low cost, and increased reliability of the 1200V three-phase inverter IPMs. Simulation and experimental results of a 1200V 30A three-level NPC inverter IPM are provided to verify the effectiveness of the proposed 1200V cascaded HVIC gate drive circuit for the 1200V three-level NPC inverter IPM.
    2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014; 03/2014
  • Keyue Smedley, Gregory Smedley
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    ABSTRACT: This keynote speech addresses some of the tough challenges that the power grid is facing today, discusses the path forward, and projects a vision fur the future. The speech concludes that power electronics is the enabling technology for a smart, robust, and efficient energy superhighway.
    2013 5th International Conference on Power Electronics Systems and Applications (PESA) New Energy Conversion for the 21st Century; 12/2013
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    ABSTRACT: The flyback converter is a popular topology for implementing low power and multiple output power supplies. However, the high leakage inductance of the flyback transformer causes high voltage spikes that can damage the main transistor when the switch is turned OFF. Therefore, a turn-off snubber is needed to limit the peak voltage stress. This paper presents the analysis of an energy regenerative snubber using the graphical state-plane technique. The undertaken approach yields a clear-cut design procedure for minimum switch voltage stress. Experimental evaluation of the energy regenerative snubber in comparison with other common snubbers shows that under the same voltage stress the efficiency of energy regenerative snubber has 8% improvement on average over an RCD snubber and 2% improvement over the nondissipative LC snubber.
    IEEE Transactions on Power Electronics 11/2013; 28(11):5323-5332. DOI:10.1109/TPEL.2013.2243845 · 5.73 Impact Factor
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    ABSTRACT: The fault current limiter is considered a viable solution for reducing the fault current in the power line. In the U.S., great effort has been reported in academia and industry in developing such devices. However, demonstrating a fault current limiter in the live power grid is challenging not only technologically but regulatory. This paper reports a joint effort of academia, industry, and utility on prototyping and testing of saturable core high temperature superconductive fault current limiters (HTS FCLs). This device is the first fully operational HTS FCL installed on the commercial medium voltage distribution grid in the U.S.
    IEEE Transactions on Power Delivery 07/2013; 28(3):1271-1279. DOI:10.1109/TPWRD.2013.2256801 · 1.66 Impact Factor
  • Source
    Arash Khoshkbar-Sadigh, K. M. Smedley
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    ABSTRACT: Voltage sag is identified as a common undesirable power quality phenomenon in the distribution systems, which causes malfunction of sensitive loads and may even damage them. Implementation of dynamic voltage restorer (DVR) makes it possible to suppress the effect of this phenomenon to protect sensitive loads. For this purpose, the time response of voltage sag detection is crucial. This paper proposes a simple detection method to achieve fast response without the need of phased locked loop (PLL), look-up table or complex computations. The proposed method has been implemented through simulation and experiment; and it has been tested under various conditions considering possible cases such as different amount of voltage sag, different amount of voltage sag angle at which voltage sag occurs and line frequency variation. According to the obtained results, the best and worst detection time of proposed method were measured 0.26 and 0.68 ms, respectively, which shows fast response of proposed method. Both simulation and experimental results demonstrate the performance and effectiveness of proposed method.
    APEC; 03/2013
  • Wensheng Song, Xiaoyun Feng, Keyue Ma Smedley
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    ABSTRACT: Single-phase three-level neutral point clamped (NPC) converters are widely applied in high-speed railway electrical traction drive systems. A significant problem related to the single-phase three-level NPC converters is the fluctuation of the neutral-point voltage. In this paper, a capacitor voltage balancing technique is proposed that injects an offset voltage into the sinusoidal modulating signals of the conventional carrier-based pulsewidth modulation (CBPWM) method. Furthermore, when the injected offset voltage is maximized, it cannot only balance the dc-link capacitors voltages, but also reduce switching losses. Theoretical analysis has shown that both methods can control the neutral point voltage effectively, but the neutral point voltage controller in the CBPWM with maximum offset voltage injection (CBPWM-MOVI) has a faster dynamic response. It was observed that the high-order harmonics frequencies of the line current are centered around the twice switching frequency in the CBPWM with the offset voltage injection (CBPWM-OVI) but are centered around the switching frequency in the CBPWM-MOVI. And also, the CBPWM-MOVI has switching commutations number at least 25% below that of the CBPWM-OVI in one modulating signal period. The performances of the two strategies were verified by simulation and experimental tests.
    IEEE Transactions on Power Electronics 03/2013; 28(3-3):1083-1095. DOI:10.1109/TPEL.2012.2210248 · 5.73 Impact Factor
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    ABSTRACT: This study is concerned with application of the universal one-cycle control (OCC) technique to implement a three-phase AC electronic load. The proposed AC electronic load is able to emulate complex load behaviour. The study describes the principles of operation and the digital implementation of AC electronics load. To validate the approach, the start-up transient of an induction motor was successfully emulated. Both the simulation and experimental results are reported.
    IET Power Electronics 07/2012; 5(6):827-832. DOI:10.1049/iet-pel.2011.0187 · 1.32 Impact Factor
  • Alexander Abramovitz, K.M. Smedley
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    ABSTRACT: This paper presents a comparative survey of research activities and emerging technologies of solid-state fault current limiters for power distribution systems.
    IEEE Transactions on Power Electronics 06/2012; 27(6):2770-2782. DOI:10.1109/TPEL.2011.2174804 · 5.73 Impact Factor
  • Source
    Khoshkbar A Sadigh, KM Smedley
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    ABSTRACT: Voltage sag is a common and undesirable power quality phenomenon in the distribution systems which puts sensitive loads under the risk. An effective solution to mitigate this phenomenon is to use dynamic voltage restorers and consequently, protect sensitive loads. Four basics compensation methods were proposed in the research community to eliminate the voltage sags and minimize the voltage disturbances at load side. This paper provides a review of those voltage compensation strategies with detailed discussions and comparisons to highlight their advantages and disadvantages.
    Power and Energy Society General Meeting, 2012 IEEE; 01/2012
  • Pengju Sun, Luowei Zhou, Keyue Ma Smedley
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    ABSTRACT: This paper presents a reconfigurable structure dc-dc converter with wide output range and constant peak power (RS- WOCP). This converter is an extension of the traditional isolated dc-dc converter with two output channels by adding an active switch and two diodes. Theoretical analysis indicates that the pro- posed RS-WOCP converter is able to smoothly reconfigure the output channels in parallel or series to realize wide output voltage range. With this approach, the output voltage is shared equally in the series operating mode and so is the output current in the parallel operating mode. Therefore, the power rating of devices is significantly reduced and the output rectifiers and filters can distribute power losses and thermal stresses. Operating principle, control strategy, modeling, and stability analysis are illustrated in this paper. An experimental prototype of a 200-W DSP-based RS- WOCP converter was built. The experimental results have verified the steady-state performance and fast dynamic response in the whole output voltage range. Comparisons with two close relatives of wide output converters show that the proposed RS-WOCP con- verter is advantageous for wide output range constant peak power applications.
    IEEE Transactions on Power Electronics 10/2011; 26(10):2925-2935. DOI:10.1109/TPEL.2011.2129576 · 5.73 Impact Factor
  • Alexander Abramovitz, K.M. Smedley
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    ABSTRACT: This paper presents a single-phase power factor corrector based on a tapped-inductor buck-boost converter. This paper suggests simplified models of the power stage under current-mode control and derives small-signal transfer functions of both the current and voltage control loops. Design rules for implementation of the proposed power factor corrector (PFC) are also suggested. The proposed PFC features low dc bus voltage, arbitrary lower than the peak line voltage. The proposed PFC is suitable for applications in computers and communications, where dc isolation can be provided by the downstream dc/dc converters. Simulation and experimental results are also reported and stand in good agreement with theoretical expectations.
    IEEE Transactions on Power Electronics 09/2011; 26(9):2637-2649. DOI:10.1109/TPEL.2011.2122270 · 5.73 Impact Factor

Publication Stats

3k Citations
332.46 Total Impact Points


  • 1994–2015
    • University of California, Irvine
      • • Department of Electrical Engineering and Computer Science
      • • Department of Mechanical and Aerospace Engineering
      Irvine, California, United States
  • 2008
    • University of California, Davis
      • Department of Electrical and Computer Engineering
      Davis, California, United States
  • 2007
    • Shamoon College of Engineering
      Ukreir, Southern District, Israel
  • 1992
    • California Institute of Technology
      Pasadena, California, United States