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Applied Power Electronics Conference and Exposition, 1997. APEC '97 Conference Proceedings 1997., Twelfth Annual

Date 27-27 Feb. 1997

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  • Twelfth Annual Applied Power Electronics Conference And Exposition [front matter]

    Page(s): i - xxii
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    Freely Available from IEEE
  • Author index

    Page(s): 1069 - 1070
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    Freely Available from IEEE
  • Zero-voltage-transition DC-link techniques for three-phase AC-DC-AC PWM converters

    Page(s): 692 - 698 vol.2
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    New soft-switching topologies are proposed for AC-DC-AC power converters by applying a soft-switching mechanism to the common DC link, and using a single auxiliary circuit, which provides the soft-switching function to all of the twelve main switches. The switches in the AC-DC power converter and the DC link switch are turned on with zero voltage, while the switches in the DC-AC power converter are turned off with zero-voltage, resulting in much reduced switching losses. With coordinated control of the AC-DC and the DC-AC power converters, the soft-switching circuit is actuated only once in every switching cycle, and has much less power loss than in existing schemes View full abstract»

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  • Analysis and design of a high power factor, single-stage electronic ballast with dimming feature

    Page(s): 1030 - 1036 vol.2
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    The analysis, design and practical consideration of a single-stage electronic ballast with a dimming feature and unity power factor are presented in this paper. The proposed single-stage ballast is the combination of a boost power converter and a half-bridge series-resonant parallel-loaded inverter. The boost semi-stage, working in the discontinuous conduction mode, functions as a power factor corrector and the inverter semi-stage, operated above resonance, is employed to ballast the lamp. Replacing the lamp with a plasma model, analysis of the ballast is fulfilled. The dimming feature is carried out by using pulse-width modulation and variable-frequency controls simultaneously. The proposed ballast can save a controller, reduce size and possibly increase system reliability over a conventional two-stage system. A prototype was implemented to verify the theoretical discussion. The hardware measurements have shown that the desired performance can be achieved feasibly View full abstract»

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  • Analysis and evaluation of a lossless turn-on snubber

    Page(s): 757 - 763 vol.2
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    A lossless turn-on snubber was studied analytically, by simulation and experimentally. Limits were found for the proper operation of the snubber and are expressed as permissible duty cycle as a function of input current. It was found that a modified version of the snubber, which includes a tapped main inductor, improves the performance by allowing a wider operational range. The experimental results confirm the theoretical analysis. A reduction of power losses of about 19 W was observed when the snubber was implemented in a 1 kW boost power converter View full abstract»

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  • Maintaining soft switching in a phase-shifted bipolar DC-to-DC converter

    Page(s): 783 - 789 vol.2
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    In a bipolar DC-to-DC power converter, a phase-shift scheme cannot maintain soft switching when the load current is negative. A simple and elegant solution is proposed for the first time. The end result is an operation symmetrical to that of the case with positive current, hence retaining all the benefits. The measured results support fully the analytical predictions. An efficiency of 94.5% was observed on a 1.5 kW power converter breadboard for operations with positive and negative load currents, respectively View full abstract»

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  • Fiat Lux: a fluorescent lamp transceiver

    Page(s): 1037 - 1041 vol.2
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    The prevalence of electric discharge illumination has led the authors to consider ways to use discharge lamps for communication. This paper describes an optical transceiver system which transmits by modulating the lamp arc. The prototype power electronic lamp ballast uses a pulse frequency modulation scheme which ensures no perceptible flicker View full abstract»

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  • Non-linear control and stabilization of PWM current source rectifiers in the regeneration mode

    Page(s): 902 - 908 vol.2
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    PWM current source rectifiers are the preferred alternative to phase-controlled rectifiers when power factor and harmonic distortion are of concern. However, these rectifiers exhibit nonlinear characteristics and may become unstable under regenerative conditions, such as are encountered in current source inverter-based AC drives operating in the braking mode. This paper offers a solution to the design of stable and operating point independent controllers. It uses input-output linearization based on a nonlinear state variable feedback approach. Furthermore, an instantaneous power feedforward term is used to stabilize the control system. The theoretical analysis and controller design are presented. Results demonstrate the superior performance of the proposed technique over standard linear controllers View full abstract»

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  • A unique analysis and design of ZCS resonant inverters

    Page(s): 1008 - 1013 vol.2
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    The authors present the analysis and design of current-fed Class-M, and voltage-fed Class-L zero current switching (ZCS) resonant inverters. These inverters are suitable for high voltage applications due to their parallel resonant nature. Operations of the circuits are illustrated by detailed descriptions. A design procedure and an example are presented and verified with experiments. A simple steady-state circuit model is also introduced View full abstract»

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  • Robust control of single phase UPS

    Page(s): 825 - 831 vol.2
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    This paper deals with the design of a robust control scheme for single phase uninterruptible power supplies (UPS). UPS systems must provide sinusoidal output voltage irrespective of operating conditions, e.g. in presence of nonlinear and variable loads. In this paper, variations of the operating conditions are modelled as perturbations of the plant transfer function, so that control design can be approached by robust control techniques. Modelling plant and perturbations according to the linear fractional transformation (LFT) standard structure, allows the use of μ-synthesis to design a robust controller, able to guarantee the specified performances in any operating condition, including nonlinear or step-changing loads. In addition, the paper shows how the main drawback of the robust controller, that is its high order, can be compensated by order reduction techniques, thus allowing a simple implementation. The superiority of the reduced order robust controller is demonstrated by a comparison with a conventional controller View full abstract»

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  • Circuit-design criteria for improvement of xenon flash-lamp performance (lamp life, light-pulse, narrowness, uniformity of light intensity in a series of flashes)

    Page(s): 1057 - 1061 vol.2
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    Xenon flash lamps are one of the brightest light sources available. They are used from simple applications like camera flashes to extremely demanding ones such as photometry, chemical analysis, spectroscopy, etc. A power supply to drive a xenon lamp must provide a substantially high voltage and current, and must provide a controlled high voltage pulse to strike the arc. The influence of the parameters of the power supply and parasitics on light output, stability and lamp life is analyzed in this paper. The experimental results have been evaluated with several types of lamps and with power supplies developed to make them View full abstract»

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  • Capacitors as an element in advanced power sources in power electronics systems

    Page(s): 596 - 601 vol.2
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    As consumer and industrial requirements for compact, high power density, electrical power systems grow substantially over the next decade, development of high power/energy density capacitor technology is a major enabling technology component element. This paper describes the results of a continuing study of the Power Sources Manufacturer's Association Capacitor R&D Committee of capacitor technologies for microsecond to fractional-second electrical energy storage, discharge, filtering and power conditioning applications. For such applications, capacitor technology is unequalled in flexibility and adaptability to meet a broad range of requirements in the future View full abstract»

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  • A synchronous-frame controller for a single-phase sine wave inverter

    Page(s): 813 - 819 vol.2
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    A synchronous frame controller for a single-phase PWM inverter with an LC output filter is presented. These types of inverters are often used in uninterruptible power supplies (UPS) where a sinewave output voltage is to be maintained. The advantages of a synchronous frame regulator are well known in three-phase controllers where regulated AC variables (voltage, current, flux) are “-rotated” into a frame synchronous to the fundamental output frequency where they appear as DC vector quantities. Such a controller can regulate the steady-state errors of the corresponding DC quantities to zero. While the familiar dq transformation is not applicable in a single-phase system, a frame synchronous to the output fundamental can be formed by recognizing that the filter capacitor current and the filter capacitor voltage are identically 90° out of phase. Thus, orthogonal quantities much like dq components exist, and can be used to create a rotating frame where a composite reference vector can be summed with a similar measured vector. Simulations of a synchronous controller and a conventional state-feedback cascaded controller are presented and compared. Preliminary experimental results are also presented View full abstract»

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  • Sensor-less torque control of salient-pole synchronous motor at zero speed operation

    Page(s): 715 - 720 vol.2
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    A position and speed sensorless control scheme using the counter EMF of PM motors debases the control performance at low speed. Here, the authors propose a controllable system at full speed, including zero speed, using saliency. At low speed, sensorless control is performed by observing a current ripple at a time when an alternating voltage has been applied to the salient-pole motor. Also, for discriminating the S and N poles of the magnet, magnetic saturation is used. A device has been applied to the motor rotor to allow the magnetic saturation to be brought about easily. Further, at times of high speed, a full speed range drive has been accomplished by switching smoothly over to a sensorless driving system, making use of the counter EMF View full abstract»

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  • High-performance soft-switched three-phase converter with sinusoidal input current and unity power factor

    Page(s): 672 - 678 vol.2
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    A soft-switching three-phase PWM-PFC power converter is proposed in this paper. In discontinuous mode power converters, the devices must be switched off at a maximum inductor current. To achieve zero voltage switching, the proposed power converter is constructed by using a resonant network in parallel with the switch of a conventional PWM power converter. The new PWM power converter achieves soft-switching for all switching devices without increasing their voltage and current stresses View full abstract»

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  • Analysis, design and experiments of a high power factor electronic ballast

    Page(s): 1023 - 1029 vol.2
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    A charge pump high power factor converter cell is first derived, and its unity power factor condition is then reviewed. A single stage high power factor electronic ballast using the charge pump concept is then analyzed. Design criteria are derived to optimize the electronic ballast based on the steady state analysis. Constant lamp power operations associated with its control are also discussed. Large signal simulation and experimental results verify the theoretical analysis. It is shown that the designed electronic ballast has 0.995 power factor and 5% total harmonic distortion with lamp power variation within ±15% when the line input voltage changes ±10% View full abstract»

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  • Transient performance of a single-stage UPS system for single-phase trapezoidal-shaped AC voltage supplies

    Page(s): 832 - 838 vol.2
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    A high performance single-stage UPS system for single-phase AC power supply systems is presented. The topology generates a trapezoidal-shaped load voltage that is synchronized with the AC supply; therefore, a small DC link capacitor is required. These features lead to a high input power factor (0.94 at nominal voltage) and due to the single-stage structure, high efficiency (93% at nominal voltage) and high reliability are achieved. In this paper, the dynamic performance of the UPS system is analyzed under different transient conditions, specifically: (a) supply to battery; (b) battery to supply transition; (c) load transient; and (d) supply/battery voltage transient. The input power factor and efficiency as a function of the load and supply voltage are also included. The dynamic and static evaluations are performed on a 1 kVA UPS system View full abstract»

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  • A technique for reducing rectifier reverse-recovery-related losses in high-voltage, high-power boost converters

    Page(s): 1000 - 1007 vol.2
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    A circuit technique that reduces the boost power converter losses caused by the reverse-recovery characteristics of the rectifier is described. The losses are reduced by inserting an inductor in the series path of the boost switch and the rectifier to control the di/dt rate of the rectifier during its turn-off. The energy from the inductor after the boost switch turn-off is returned to the input or delivered to the output via an active snubber. The same technique can be extended to any member of the PWM power converter family View full abstract»

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  • A low-cost control IC for single-transistor ZVS cold-cathode fluorescent lamp inverters and DC/DC converters

    Page(s): 1042 - 1049 vol.2
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    The paper reviews the various inverter topologies for cold-cathode fluorescent lamps, discusses the analysis and control of the class E inverter, and introduces a new control IC developed for such inverters and also for ZVS DC/DC power converters. The IC features a zero-voltage detector, switch overdissipation protection, soft start, pulse-by-pulse current limit, overvoltage protection, and on/off switching with a low-current stand-by mode. The primary use of the IC is in inverters for cold-cathode fluorescent lamps for display backlight applications, but the IC is also suitable for controlling ZVS quasi-resonant and multi-resonant DC/DC power converters View full abstract»

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  • A novel three-phase three-switch three-level high power factor SEPIC-type AC-to-DC converter

    Page(s): 657 - 665 vol.2
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    In this paper, the topology of a new three-phase three-switch three-level PWM rectifier system is derived based on the basic structure of a DC-to-DC SEPIC power converter. The system is characterized by full controllability of the power flow (independent of the level of the output voltage) and by a sinusoidal mains current shape in phase with the mains voltage. The operating principle of the power converter is explained based on the conduction states of a bridge leg within a pulse period. The stationary operating behavior is analyzed by digital simulation based on the control of the mains phase currents by independent ramp-comparison controllers. Furthermore, a mathematical description of the operating behavior of the three-phase system including the coupling of the phase current controllers (given due to the floating mains star point) is discussed. Finally, results of an experimental investigation of a laboratory model of the power converter are presented View full abstract»

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  • Class L-a new single-ended DC-to-AC power inverter

    Page(s): 776 - 782 vol.2
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    A new single-ended, zero current switching DC-to-AC power inverter named the Class-L introduced. Because of its parallel resonant nature, the Class-L inverter is well-suited for high voltage applications. Circuit operation is illustrated by a detailed description and a ballast application is given for driving a cold cathode fluorescent lamp. Solution for the output characteristics of the inverter is illustrated by the output plane plot of the inverter. Experimental results are also presented View full abstract»

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  • Fast space vector modulation based on a neurocomputing digital signal processor

    Page(s): 872 - 878 vol.2
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    This paper presents a novel approach to the implementation of the space vector modulation (SVM). The proposed technique takes advantage of a modified Kohonen's competitive layer to calculate the on duration of the adjacent switching state vectors. By using this technique: (a) the hardware and software complexity of the system is reduced; (b) the maximum attainable switching frequency and thus the bandwidth of the control system is increased; and (c) the waveform degradation and parasitic harmonics resulting from inaccurate calculations are avoided. The proposed method is compared to the conventional implementations of SVM techniques in terms of hardware/software requirements, switching frequency, computation time, and harmonic spectra. The method is applied to a DSP controlled 3 kVA unit (voltage source inverter) and experimental results verify the validity of theoretical and simulation results View full abstract»

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  • A comparison of three-phase resonant and PWM converters for high current, high power applications

    Page(s): 631 - 637 vol.2
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    This paper studies the implementation of three-phase DC-DC power converters for high current, high power applications. The frequency adjustment for constant voltage, and constant current operation of an LCC series-parallel resonant power converter are determined. An LCC resonant power converter and a PWM power converter are analyzed, designed and experimentally tested at a current of 700 A, and a power of 5 kW. Conclusions are drawn regarding the most feasible solution View full abstract»

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  • Forward converter with current-doubler rectifier: analysis, design, and evaluation results

    Page(s): 605 - 611 vol.2
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    Complete steady-state analysis of a forward power converter with a current-doubler rectifier is provided. The advantages and disadvantages of this topology, as compared to the conventional forward power converter, are discussed. Step-by-step design guidelines are also outlined. Finally, experimental evaluation results obtained on a 3.3 V, 50 A DC/DC power converter prototype for the 40-60 V input-voltage range are presented View full abstract»

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  • Design of a 1.5 V output voltage on-board DC/DC converter with magnetic components integrated in a multilayer PCB

    Page(s): 764 - 769 vol.2
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    Computer and telecommunication systems tend to demand lower supply voltages than 3.3 V. This fact raises the challenge of obtaining high efficiency DC/DC power converters with low output voltage. The authors have implemented a compact power converter with an output voltage of 1.5 V. The output power is 5 W and the power converter has been provided with galvanic isolation between input and output sides. The windings of the magnetic components are directly integrated in the PCB, which allows a reduction in size. Self-driven synchronous rectification allows one to obtain very high efficiency (81.2% at nominal conditions, 85.3% maximum) for such a low output voltage View full abstract»

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