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23rd IEEE Instrumentation and Measurement Technology Conference

作者： Horak, Goran Vasic, Darko Bilas, Vedran Krkac, Ognjen Univ Zagreb Fac Elect Engn & Comp HR-10000 Zagreb Croatia

ISBN: (纸本)9780780393592

The electronic instrumentation which operates in the high-temperature environment of an oil well should be specially designed. Analog-to-digital converters are critical components in well-logging applications with only few high-temperature-rated commercial components on the market. Our objective is to realize a custom AID Conversion module for multichannel well-logging applications following the smart-sensor concept and using proven, reliable and available electronic components. This paper presents a simple and robust digitalization module which utilizes a pulse-width modulator in combination with a phase-locked loop. We are presenting results of a high-temperature functional evaluation of a demonstration prototype implemented using commercial- and industrial-grade integrated components in combination with high-temperature rated passive components. The module's operating range is defined by the 5V unipolar supply voltage. The effective number of bits of the digitalization module is between 10 and 13 over the temperature range 25-175 degrees C.

关键词： analog-to-digital conversion pulse-width modulation phase-locked loop high-temperature electronics smart sensors

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Topological and modulation design of three-level Z-source inverters

Topological and modulation design of three-level Z-source in...

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CES/IEEE 5th International Power Electronics and Motion Control Conference

作者： Loh, P. C. Gao, F. Blaabjerg, F. Nanyang Technol Univ Sch Elect & Elect Engn Singapore Singapore Aalborg Univ Inst Energy Technol Aalborg Denmark

ISBN: (纸本)1424404487

This paper presents the development of two three-level cascaded Z-source inverters, whose output voltage can be stepped down or up unlike a traditional buck three-level inverter. The proposed inverters are designed using two three-phase voltage-source inverter bridges, supplied by two uniquely designed Z-source impedance networks and cascaded at either their do sides to form a dc-link-cascaded Z-source inverter or, ac outputs using single-phase transformers to form a dual Z-source inverter. For controlling both inverters, various modulation schemes are designed with their performances verified experimentally using an implemented laboratory prototype.

关键词： three-level inverters voltage-source inverters buck-boost pulse-width modulation

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CREEPAGE CONTROL FOR USE IN WHEELSLIDE PROTECTION SYSTEMS

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IFAC Proceedings Volumes 2006年第12期39卷 597-602页

作者： Thorsten Stützle Uwe Viereck Anton Stribersky Wolfgang Rulka Manfred Enning Dirk Abel RWTH Aachen University Institute of Automatic Control Steinbachstraβe 54 D-52074 Aachen Germany RWTH Aachen University Institute of Rail Vehicles and Materials-Handling Technology Germany Siemens Transportation Systems GmbH & Co KG Vienna Austria Siemens AG Transportation Systems Munich Germany

In order to achieve acceptable braking distances, the wheelslide protection controller of a railway vehicle should hold an operating point in the macro-slip range on the decreasing branch of the creep force curve. Based on mathematical models of the railway vehicle, the creep force characteristics and the brake system, a stability analysis is performed for the open-loop system during braking in the macro-slip range. In addition, a creepage controller that stabilises the closed loop over the entire vehicle velocity range is presented and its performance is discussed with the help of simulation results.

关键词： Railways Vehicle dynamics Antiskid control Stability analysis pulse-width modulation

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Selective Harmonic Controlling for Three-Level High Power Active Front End Converter with Low Switching Frequency

Selective Harmonic Controlling for Three-Level High Power Ac...

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CES/IEEE 5th International Power Electronics and Motion Control Conference

作者： M. Braun Institute of Power Electronics and Electrical Drives University of Karlsruhe Karlsruhe Germany

Controlling of a specific harmonic by a switching converter with switching frequency lower than 1 kHz was originally implemented by two-level Optimal pulse pattern with Unsymmetrical Switching angles [10], namely by OPUS-technique. That means, given a desired fundamental and one or more specific harmonics, the problem is to find the switching times (angles) that produce the fundamental while generating specifically all chosen harmonics. Based on the OPUS-technique a three-level optimal pulse pattern is proposed for high power level applications with low switching frequency. The transcendental mathematical equations are developed. Using the prior results of all complete solutions of selective harmonic elimination (SHE) the solutions of the new equations can be found by Newton iteration method. In particularly, the modulation performance of OPUS-technique for three-level Optimal pulse pattern with Unsymmetrical Switching angles is demonstrated by the trajectory of the converter voltage space vector integral. Finally, the control range of a specific harmonic is given by OPUS-technique.

关键词： partly unsymmetrical optimal pulse pattern pulse-width modulation voltage source inverter harmonics control range

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A Low-Cost Gate Driver Design Using Bootstrap Capacitors for Multilevel MOSFET Inverters

A Low-Cost Gate Driver Design Using Bootstrap Capacitors for...

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CES/IEEE 5th International Power Electronics and Motion Control Conference

作者： J.J.Graczkowski K.L.Neff Student Member IEEE University of Wisconsin-Platteville/Electrical Engineering Department Platteville WI USA Student Member IEEE University of Wisconsin-Platteville/Electrical Engineering Department Platteville WI USA

Multilevel inverters require a large number of power semiconductors. The gate driver for each power semiconductor requires its own floating or isolated dc voltage source. Traditional methods on meeting the requirement are expensive and bulky. This paper presents a gate driver design for floating voltage source type multUevel inverters. Bootstrap capacitors are used to form the floating voltage sources in the design, which allows a single DC power supply to be used by all the gate drivers. Specially configured diode plus the proper charging cycles maintain adequate capacitor voltage levels. Such a simple and low cost solution allows user to utilize the easy accessible single-channel gate drivers for multilevel inverter applications without the extra cost on the bulky isolated dc power supplies for each gate driver. A prototype 3-cell 8-level floating voltage source inverter using the method illustrates the technique.

关键词： Multilevel Inverter Bootstrap Capacitor pulse-width modulation Gate Driver MOSFET Inverter, Capacitor Voltage Balancing Floating Voltage Source Inverter Flying Capacitor Inverter.

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The use of infra-red light-modulated temperature in DSC created by pulse-width modulation

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THERMOCHIMICA ACTA 2002年第2期381卷 139-146页

作者： Kamasa, P Buzin, A Pyda, M Wunderlich, B Univ Tennessee Dept Chem Knoxville TN 37996 USA Oak Ridge Natl Lab Div Chem & Analyt Sci Oak Ridge TN 37831 USA

Infra-red light, generated by diodes, is applied to produce a sinusoidal temperature modulation in the standard heat-flux DSC of TA instruments. The temperature of the sample and reference are controlled by both, the original temperature controller of the instrument, and by the radiant energy generated by two high-power infra-red light-emitting diodes (LEDs). This allows for isothermal or quasi-isothermal experimentation in the standard mode of operation of the calorimeter. The additional infra-red irradiation is provided only for temperature modulation. The radiant energy transferred to the specimens is controlled by pulse-width modulation (PWM) which provides a high linearity in the temperature modulation program. This feature enables to obtain any arbitrary temperature profile with the limits of frequency set by the calorimeter response and speed of the computer. Simple electronics and a computer algorithm for the PWM control are described. The method was tested in the melting range of indium and by measurement of the heat capacity of sapphire (Al2O3) and polystyrene. The problem of frequency correction arising from a wide frequency range is analyzed and discussed. Published by Elsevier Science B. V.

关键词： temperature-modulated DSC infra-red-modulated temperatures pulse-width modulation

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Buffer amplifier and LED improve PWM power controller's low-load operation

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EDN 2005年第19期50卷 89-90页

作者： Mirsky, G LaMarche Mfg Co Des Plaines IL USA

Texas Instruments' UCC3895 offers a good base for building a high-efficiency,pulse-width-modulated, switched-mode power supply that suits either current- or voltage-modecontrol. Designed for driving a full-bridge power inverter using two sets of complementary outputs,Out A through D, the circuit controls power by phase-shifting outputs C and D with respect to A andB. The manufacturer's data sheet provides a detailed description (Reference 1). However, whenlightly loaded and configured for current-mode control, the controller can produce asymmetric-widthpulses on its lagging outputs, C and D, under start-up conditions. Reference 2 provides a completedescription of the problem and a workaround.

关键词： pulse-width modulation pulse modulation (Electronics) Switching power supplies Electronics

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Modeling of a single-switch quadratic buck converter

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2005年第4期41卷 1451-1457页

作者： Carbajal-Gutiérrez, EE Morales-Saldañna, JA Leyva-Ramos, I Univ Autonoma San Luis Potosi Fac Ingn San Luis Potosi 78290 Mexico

Ready-to-use nonlinear and linear averaged models for a single-switch quadratic buck converter are given. The nonlinear model is obtained from an averaged equivalent circuit model of the converter using the PWM-switch (pulsewidth modulation) model. The linear model is obtained by applying a small-signal perturbation to the corresponding averaged state-space description. The result shows that this quadratic converter exhibits the transfer characteristics of a fourth-order system. The resulting models are only valid in the continuous conduction mode (CCM). The validity of the proposed models was verified by computer simulation using PSPICE and MATLAB/SIMULINK for a specified converter. Experimental results on a prototype converter are also presented.

关键词： CASCADE converters DIGITAL-to-analog converters pulse-width modulation pulse modulation (Electronics) ELECTRIC switchgear ELECTRONIC systems

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An interface circuit for measuring capacitance changes based upon capacitance-to-duty cycle (CDC) converter

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IEEE SENSORS JOURNAL 2005年第3期5卷 403-410页

作者： Ignjatovic, Z Bocko, MF Univ Rochester Rochester NY 14627 USA

We present a direct-to-digital capacitive sensor readout circuit that converts capacitance changes of a sensor element to changes of the duty cycle of a square-wave oscillator, which, in turn, is converted to a digital output by a counter. The readout circuit resembles a single-slope analog-to-digital converter structure. There are several advantages of this readout scheme. First, due to its simplicity and low number of components, the power consumption of the circuit is expected to be significantly smaller than in similar digital readout designs. Furthermore, linearization of the output may be achieved using an EEPROM lookup table. Another advantage is the possibility of performing adaptive measurements where the sensor resolution and bandwidth may be changed via the readout circuit software. Finally, we present a theory of the adaptive measurement and an analysis of the design tradeoffs. The capacitance-to-duty cycle readout circuit may achieve large bandwidth and high resolution in a modern low-voltage, low-power CMOS implementation. The performance of a prototype readout circuit built from discrete components is 13-bit effective resolution with a 1-kHz bandwidth.

关键词： adaptive systems analog-to-digital (A/D) conversion capacitance measurement pulse-width modulation

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Shunt regulator eases power-supply-start-up woes

EDN

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EDN 2005年第22期50卷 100-+页

作者： O'Loughlin, M Texas Instruments Inc Nashua NH USA

This article presents information on the TL431 three-terminal shunt regulator. The shunt regulator's internal circuitry comprises a precision voltage reference, an operational amplifier, and a shunt transistor. In a typical voltage-regulator application, two external resistors determine the shunt-regulated output voltage at the lower end of load resistor. The TL431 and a few external active and passive components can serve as a low-power auxiliary power supply for a switched-mode-power-supply pulse-width-modulated (PWM) controller. In some power-supply designs, an auxiliary winding on the step-down transformer supplies power to the PWM controller. Under light output loads, the auxiliary winding may supply inadequate power to the PWM controller.

关键词： Shunt electric reactors Electric resistors Electronic amplifiers Voltage regulators Switching power supplies pulse-width modulation

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