The power system of Hydro-Quebec has a peak load of approximately 27 GW. The great distance between the production sites and the load centers introduces stability limitations, which is the reason why the Quebec grid cannot be economically synchronized (through ac transmission with limited capacity) with the U.S. northeastern network. Power exports are therefore dependent on the use of HVDC links ...

Enhancement of the overall system dynamic performance of an existing ac/dc scheme is possible by minor modifications in the NVDC controls. The paper presents some control modifications for the Chateauguay HVDC back-to-back 1000 MW scheme with interconnections to the Beauharnois generators and to the 765 kV intertie to NYPA. These modifications lead to a ...

leg regulates the voltages on their capacitors independently of the others. Main Features #12;AC/DC/AC C: value of the DC-link capacitors Voltage Oscillation Amplitude #12;AC/DC/AC Converters: TwoAC/DC/AC Converters: Two-Level and Multilevel VSI Page 1 Socrates � Erasmus Visit ...

... Extension of the NIST AC-DC Difference ... The NIST primary standards of ac-dc difference for current are multijunction thermal converters (MJTCs). ...

This paper describes the control design of the Santo tome' back-to-back HVDC link. The Santo Tome' HVDC converter will be the second dc link asynchronously connecting the Argentina and Brazil power systems. This paper focuses on the design of the reactive power control, automatic power control, load frequency control, power modulation ...

This study presents the design and cold testing of a Q-band TE01-mode converter. Integrating Marie transducer and the design of Ching-Fang Yu and Tsun-Hsu Chang, we have improved the design of circular TE01-mode converter. The working principle of each section are analyzed and discussed. Two identical converters are joined ...

A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a...

The feasibility for implementation of a concept for direct ac/dc multikilowatt power conversion with

... and a pair of positive and negative switching DC/DC converter sections connected to said AC/DC converter section and receiving a pair of positive ...

This paper presents the development of a control scheme for a multilevel diode-clamped converter connected in a series-parallel fashion to the electrical system such that it can compensate for deviations in utility voltage (sag, surge, and unbalance) and act as a harmonic and/or reactive current source for a load. New carrier-based multilevel pulsewidth modulation techniques ...

... 555 PRECISION DC VOLTAGE STANDARD 559 400-CYCLE OSCILLATOR 560 AC - DC CONVERTER 565 TRUCK, HAND, AUTONAVIGATOR ...

Abstract�This paper discusses the basic construction procedure and topological possibilities of creating ac/dc converters out of simple dc/dc converters. It is shown that two separately controlled dc/dc converters are sufficient for producing a regulated dc output and shaping the input current, from an ac voltage ...

A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the dc capacitors. The problem may be solved by use ...

A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the Direct Current (DC) capacitors. The problem may ...

The NIST calibration service for ac-dc difference of thermal current converters relies on multijunction thermal converters as the primary standards, and various thermal converters and thermoelements (TEs) as the reference and working standards. The paper ...

The NIST calibration service for ac-dc difference of thermal current converters relies on multijunction thermal converters as the primary standards, and various thermal converters and thermoelements (TEs) as the reference and working standards. Calibratio...

Conventional ac-dc converters present two important disadvantages: they create harmonic currents and require reactive power. To reduce these drawbacks, a diode rectifier is directly connected in series with a chopper controlled by pulsewidth modulation. Both are preceded by a series inductance (added to the equivalent one of the power system) and a shunt ...

Results achieved by the intermediate power level ac-dc model in Philadelphia demonstrate the unusual features and advantages of this research tool for working toward accomplishment of over-all aims of the project. Insofar as can be determined, it is presently the only facility capable of evaluating the dynamic interactions between ac-dc ...

This paper presents the results of theoretical and experimental development of a new dc-ac-dc converter for superconducting magnet power supplies. The basic operating principles of the circuit are described followed by a theoretical treatment of the dynam...

For the transfer of alternating voltage and current to the equivalent direct units, Multijunction Thermal Converters (MJTC's) have been developed, the uncertainty of which are in the range of the uncertainty of the maintenance of the electrical units. A n...

A semiautomatic ac/dc difference calibration system is described. The system operates over a frequency range of 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kV. For all voltages at frequencies in the range from 20 Hz to 20 kHz, the total u...

The use of a thin film or a planar multijunction thermal converter (PMJTC) for the ac-dc transfer of voltage and current is well established. In general, a three dimensional multijunction thermal converter (MJTC) has the advantage of accuracy and a single junction thermal converter (SJTC) has that of low cost. PMJTCs provide a ...

This paper deals with a 50-MW self-commutated BTB (Back-To-Back) system intended for power-flow control between transmission networks. It focuses on the dynamic behavior of the BTB system during single-line-to-ground (SLG) faults. During an SLG fault, a dc magnetic deviation appears in the converter-transformers used for the BTB system just after the ...

... F igue Title Pa e 43 BER-2 B/Hz, Back-to-Back, Without Randomizer ..... 68 ... 74 49 BER-1 B/Hz, Back-to-Back, Without Randomizer ..... 75 ...

Sep 18, 1997 ... Software Quality Assurance � Life Cycle Data � Back-To-Back Testing � Understanding the Failure Data � Back-To-Back Results ...

... the ac-dc difference of a customer's thermal current converter to the ac-dc difference of a ... range from 50 kHz to 100 kHz at currents from 1 mA to 20 A ...

A Telecom power supply is studied and analyzed from control system viewpoint. It consists of three stages: AC/DC rectifier, a backup battery, and a Telecom load. The AC/DC rectifier stage can be composed of paralleled DC/DC converters preceded by parallel...

A Telecom power supply is studied and analyzed from control system viewpoint. It consists of three stages: AC/DC rectifier, a backup battery, and a Telecom load. The AC/DC rectifier stage can be composed of paralleled DC/DC converters preceded by parallel...

The Chateauguay HVDC back-to-back scheme with interconnections to the 765 kV transmission to U.S.A. and to Beauharnois generators can exhibit, under certain operating conditions, second harmonic resonance problems. This paper presents a thorough analysis of the problem using an eigenvalue and frequency domain approach. The analysis explains the mechanism of exciting the second ...

A description is given of two thin-lens iron-free beta -ray spectrometers that were joined back-to-back at their source ends for electron- electron coincidence spectroscopy. For increased flexibility, the instrument was designed to be easily converted into a gamma -electron coincidence spectrometer by placing a canned NaI(Tl) crystal at the back ...

Existing 34, ac-dc low-harmonic rectiifiers are costly and require complex control schemes to minimize input current harmonics. Introduced here are three new classes of low cost 34, ac-dc high power factorllow harmonic controlled rectifiers. These are derived from parent dc-dc convrter topologies containing boost-type inputs, buck-type inputs and qwsi ...

Matrix converters offer certain advantages over conventional AC-DC-AC conversion such as elimination of reactive elements, inherent bi-directional power flow capability, increased reliability and compactness. This paper explores the reactive and harmonic compensation capability of a matrix converter. Space vector modulation technique ...

An AC-DC converter based on a parallel drive of two piezoelectric ceramic transformers was investigated. The transformers operate in a fundamental contour extensional vibration mode which has a large electromechanical coupling factor notwithstanding the use of a piezoelectric transversal effect. The converter includes Al electrolytic capacitors for ...

Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest ...

converter after the micro-power- generators. The AC/DC converter is followed by an adaptive DC/DC converter generator is rectified using an AC/DC converter. Then a DC/DC converter is used to match the output of AC/DC-LINEAR TECHNIQUES FOR INCREASING HARVESTING ENERGY Power Generator ...

This paper presents a general and efficient method for transient simulation of HVDC converters. The proposed method utilizes a new algorithm, based on network topological concepts, which provides an efficient solution to the problem of modeling the inherently nonlinear characteristics and time varying topology of static power converters caused by the ...

The possibility of abnormal harmonic generation in an ac system feeding a converter load is examined from the standpoint of automatic control systems used in modern hvdc transmission systems. It is shown that with certain types of automatic controls, the firing angles of converter valves may sustain some errors, which in turn could generate abnormal ...

The authors discuss field experience with three ac-dc converter installations. A rectifier and two self-commutated inverters comprise the evaluated equipment. Each case deals with slightly different aspects in the application of converters on power systems. The three cases compliment each other to provide insight into a majority of the ...

An inductor-converter bridge (ICB) is a solid state DC-AC-DC power converter system for bidirectional, controllable, energy transfer between two coils. The ICB is suitable for supplying large pulsed power to such magnets as the superconducting equilibrium field coil of the proposed tokamak power reactors from another superconducting ...

Existing 3{phi} ac-dc low-harmonic rectifiers are costly and require complex control schemes to minimize input current harmonics. Introduced here are two new classes of low cost 3{phi} ac-dc high power factor/low harmonic controlled rectifiers. These are derived from parent dc-dc converter topologies containing boost-type inputs and ...

Optically injection-locked single-wavelength gain-switching VCSEL based all-optical converter is demonstrated to generate RZ data at 2.5 Gbit/s with bit-error-rate of 10(-9) under receiving power of -29.3 dBm. A modified rate equation model is established to elucidate the optical injection induced gain-switching and NRZ-to-RZ data conversion in the VCSEL. The peak-to-peak ...

Fly by Math. Extract, interpret and analyze data including multiple representations of the same data from tables, double back-to-back stem-and-leaf plots, ...

... five back-to-back spacewalks to repair and service the Hubble Space Telescope. ... The Sight/Insight Astronaut Tool Development Project-Based Learning ...

... Back-to-back photodiodes have been fabricated which demonstrate capacitance ... "Noise analysis by subnetwork growth." Scott Wedge and David ...

In-line, back-to-back, and vertical layouts are the basic arrangements available to the dc terminal designer.

... Anther imporbtn advantage of tiw back-to-back diode is that one obtains greater foldover than with the single diode, since maximum nonlinearity ...

... The resulting combustion - products are ducted to the LWu ... back-to-back c,!ntrtfugal pump stages driven by a two-stage, pressure-compounded ...

This paper proposes a novel control method based on the virtual AC/DC/AC conversion for the matrix converter. The virtual AC/DC/AC conversion method is a very simple strategy to control the input current and the output voltage for the matrix converter. There are two new topics proposed in this paper. Firstly, this ...

A power factor analysis of the input part of an advanced AC/DC/AC converter for variable speed wind turbines is presented. Two types of rectifying input converters are compared: the boost rectifier, consisting of three AC inductors, a three-phase diode br...

This paper presents the results of theoretical and experimental development of a new dc-ac-dc converter for superconducting magnet power supplies. The basic operating principles of the circuit are described followed by a theoretical treatment of the dynamics and control of the system. The successful results of the first experimental operation and control ...

"This is an educational module dedicated to basic power electronic circuits. The module includes DC/DC converters, basic diode and thyristor converter systems, AC/DC inverter, space vector modulation and basic signal theory. In the future there will be minor changes (mainly additions and corrections). The material currently is ...

with rectifiers to form RF-to-dc converters having narrow-range resistive input characteristics is also treated�dc converter, comprising an inverter stage, a transformation stage, and a rectifier stage [1]�[10]. Manuscript an inverter (dc�ac) circuit, a transformation/matching circuit, and a rectifier (ac�dc) circuit. The ...

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also ...

, transportation systems, and etc., which requires a rectifier, a DC bus, and an inverter to obtain arbitrary AC parts, i.e., a virtual front-end AC/DC rectifier and a virtual DC/AC inverter, and synthesizes the switching state of the matrix converter from the both switching states of the virtual rectifier

This is volume 2 of the proceedings of the IEEE International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth held during January 1996, in New Delhi, India. The topics of this volume include AC/DC and AC/AC converters, induction generators, traction and electric vehicle drives, application of neural networks and fuzzy logic ...

This paper describes the result of work performed at the Laboratoire National de M�trologie et d'Essais (LNE) aiming at characterizing the metrological performance of analogue-to-digital converters of a commercial digital voltmeter in the 20 Hz to 400 Hz frequency range. In order to reach uncertainties at the 10?6 level, ac-dc thermal transfer techniques ...

The use of high power converters has increased tremendously. Increased demand for transportation, housing and industrial needs means that more number of power converters interact with the utility power grid. These converters are non-linear and they draw harmonic currents, significantly affecting power quality. To reduce harmonics, ...

This paper addresses the design of efficient switched-capacitor power converters. The discussion starts with a review of the fundamental limitation of switched-capacitor circuits which shows that the topology of such circuits and the ``forced`` step changes of capacitor voltages are the inherent attributes of power loss. Although the argument follows from a rather trivial ...

The rotary joint is a useful microwave component that connects a fixed part to a rotatable part. This study systematically analyzes the effect of the discontinuity on the interface of a rotary joint for several waveguide modes. Simulation results indicate that the transmission of the TE(01) mode is independent of the geometry of the joint, and thus is ideal for such application. A rotary joint ...

The rotary joint is a useful microwave component that connects a fixed part to a rotatable part. This study systematically analyzes the effect of the discontinuity on the interface of a rotary joint for several waveguide modes. Simulation results indicate that the transmission of the TE01 mode is independent of the geometry of the joint, and thus is ideal for such application. A rotary joint ...

A direct light-triggered, water-cooled thyristor valve was designed and manufactured as an extension for the Shin-Shinano frequency converter station (back-to-back system, 300MW, 125kV-2400A) of Tokyo Electric Power Co. (TEPCO) This valve incorporates the following features: (1) the world's first commercial light-triggered thyristor (LTT) valve; ...

Quasi-resonant converters are a family of single-switch resonant dc-dc converters featuring zero-current or zero-voltage switching. The topological structure uniting these resonant converters - and the rectangular-wave (PWM) converters on which they are based - leads to general models of their dc and low-frequency ...

... TECHNIQUES FOR DETERMINING PERFORMANCE AND RATINGS OF CASED CAPACITORS UNDER COMBINED AC-DC OPERATION AS A ...

Considerable incentives exist for utilities to place hvdc transmission lines along the same right of way as ac lines. One consequence of such an application is steady state induction of fundamental frequency voltages into the dc circuit. The resulting current ripple on the dc converter can cause continuous offset transformer saturation, with many consequent impacts upon system ...

amplifier, DC-DC convert- ers and high performance AC, DC and step-motor control appli- cations. Many+. Capacitor, C1, integrates in a direction to satisfy the reference current signal at IN. The IN- input will be a function of the amount of dc hysteresis gain, R3/R1 and the size of capacitor, C1. As the capacitor, C1

The paper presents a formulation for coordinating all controllable reactive power sources, including the DC converters of a multiterminal DC system, to correct bus voltage violations. Based on the formulation, an algorithm using Linear Programming solution technique has been developed. The effectiveness of this algorithm to correct bus voltage violations in a 30 bus, 5 DC ...

The feasibility for implementation of a concept for direct ac/dc multikilowatt power conversion with bidirectional transfer of energy was investigated. A 10 kHz current carrier was derived directly from a common 60 Hz three phase power system. This carrie...

The hardware development and systems applications are described for high voltage direct current (HVDC) power systems. Particular emphasis is given to exemplifying cost and operational advantages of integrated ac/dc power systems. Progress is reported in the development of the following: HVDC converters; computerized simulation of HVDC systems; circuit ...

Co and a current source n ir (n is the transformer turn ratio) [7]. A halfway rectifier Rect and an inductor Lo value of the capacitor Co current ( Coi ) the rectifier will operate under overlapping conditions = 4 = n ir OLi 1Di 2Di OCi OCv 1Di 2Di (b) Fig. 2. The rectifier's current and voltage waveforms

In response to the current imbalance phenomenon and its harmfulness, a current sharing circuit model is built up, which reveals the underlying causes for the current imbalance through a quantitative analysis. Then, a feasible approach of improvement, namely enlargement of the length of connection busbars, is proposed. After the amendment, it can be seen that the current sharing coefficient is ...

Increasing complexity of high-voltage direct current (HVDC) transmission systems places new demands on alternating current/direct current (ac/dc) power converters. The possibility of using advanced power conversion techniques, specifically force-commutate...

The final report concludes that the two most likely long-range candidates for converting dc to ac power from batteries and fuel cells are the basic current-fed line commutated inverter (a derivative of HVDC technology), and the voltage-fed conduction angl...

. However, reducing the CMV via PWM pulse pattern typically degrades the other modular performance supply AC-DC-AC power converter units. Pulse Width Modulation (PWM) is the standard approach to operate controlling the PWM pulse patterns is the most economical method as it requires no extra components and cost

This report covers effort under Contract DAAK70-77-C-0035 to further develop the ac-to-dc section or converter portion of a 15 kW general purpose power conditioner or frequency changer. Previous Delco effort under Contract DAAK02-72-C-0210 had provided a ...

Oil-immersed insulating material has an anisotropic and nonlinear conductivity. A new calculating method for the electric field in such material is developed for insulation design of converter transformers and smoothing reactors. Flashover voltages estimated from the results very closely approximate the measured ones. Dielectric test methods are discussed based on calculated ...

Increasing complexity of high voltage direct current (HVDC) transmission systems places new demands on alternating current/direct current (ac/dc) power converters. The possibility of using advanced power conversion techniques, specifically force commutated conversion, is discussed. Recommended further work includes computer simulation studies, a survey of ...

Increasing demand for low power consumption in electronics combined with continued miniaturization of electronic device components in today's analogue/digital circuits have reduced the supply voltage to sub-one volt levels. The supply voltage to integrated circuit devices are provided by AC-DC converters, which converts high frequency ac voltage to a ...

An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors ...

Time quantity one-cycle control method is proposed in this paper for unity power-factor ac-dc converters. Converters controlled by this method operate at constant switching frequency, require no current sensing, have a simple control circuit, and exhibit resistive input impedance at the ac side. Feedback loop design method is provided ...

This patent describes a static converter system operating between opposite ones of respective AC and DC buses. It comprises: at least three rectifier bridges connected in parallel to the DC buses, each rectifier bridge having three AC lines connected to the middle point of two rectifier devices in series between the two DC buses, the AC lines of one rectifier bridge being ...

Harmonic analysis based on Kirchhoff laws requires the knowledge of the spectral information of the injected currents. In practical operation of controlled converters, these current harmonics depend on the actual operating point given by the emf and the dc mean current according to the requirements of the dc load. This specification means a more difficult predetermination in ...

Furnas Centrais Eletricas SA, Brazil's regional state power company, is presently, planning to award a turnkey contract or contracts for the engineering, manufacturing, and installations of 4 bipolar ac/dc converter stations expected to cost between $700 million and $1 billion. Two stations would be located at the Itaipu hydro project and the ...

This paper describes Bonneville Power Administration's first 500-kV back-to-back shunt capacitor installation. The primary purpose of the capacitor banks is to support AC system voltage for transient stability following an outage of the HVDC Intertie line between Oregon and Southern California. Design studies and equipment requirements are detailed herein in addition ...

Jun 16, 2011 ... Because no poor seed crops occurred back-to-back, ... However it is a larger file size and some people may experience long download times. ...

Back-to-back performance tests were run on seven airline low pressure turbine (LPT) modules and four

The initial window MAY be two packets (instead of the current initial window of one packet). For packets of at most 1460 bytes, the initial window MAY be three packets. For packets of at most 1095 bytes, the initial window MAY be four packets. 2 The Burstiness of Current TCP in Slow-Start: cwnd = 1 packet:) send one data packet ( receive one ACK increase cwnd to 2 packets:) send two ...

During this time Typhoon Melor tracked from the area ... Back-to-back strong El Nino and La Nina events in 1998 and 1999 created dramatically different ...

... celebrates Mars as cultural icon by screening three sci-fi classics back-to- back. ... 9 p.m.: "War of the Worlds". Address 1: 17th & M Streets N.W. ...

Sep 29, 2005 ... Cassini performed back-to-back flybys of Saturn moons Tethys and Hyperion last weekend, coming closer than ever before to each of them. ...

The present invention contemplates a completely submersed Schottky barrier junction in order to enhance collection efficiency of photogenerated carriers. Using a buried active back-to-back thin junction allows collection of carriers generated with momentu...

Jan 22, 2011 ... 1994, Integrated Back-to-Back Barrier-N-Nsup>+sup> Varactor Diode Tripler ... Mishkin, Andrew; Korth, David; LeBlanc, Troy; Lee, Young ...

Apollo 11 Flown Star Charts. Private Collection. Scans Courtesy Larry McGlynn. These charts were printed back-to-back on a single, stiff sheet. ...

Two AN/FRC-162 radios were tested in a simplex back-to-back configuration to determine standards, alignment procedures, and operational parameters in accordance with Digital European Backbone (DEB) system requirements. The transmitter was FM modulated wit...

The problem of the weak back-to-back HVDC link is investigated by quasi-steady-state analysis and small perturbation linearized stability analysis. The large ac line impedances on either sides of the HVDC link present severe constraints so that there may be no feasible steady-state solutions unless ..cap alpha.. and ..gamma.. are co-ordinated with load demands. Formulae of ...

It is concluded that the two most likely long-range candidates for converting dc to ac power from batteries and fuel cells are the basic current-fed line commutated inverter (a derivative of HVDC technology), and the voltaged-fed conduction angle controlled force commutated inverter. Results are presented for analyses of cost, performance, and reliability which lead to the ...

The $1 million ac-dc system operation laboratory of Edison Electric Institute on the campus of the University of Pennsylvania is described.

The phenomenon of torsional oscillations as a result of series capacitor compensation and HVDC converter controllers of an AC/DC system is investigated. A feasible approach for damping the torsional modes based on coordinating the controllers of an SVC unit with the supplemental subsynchronous damping control (SSDC) of the HVDC rectifier, is presented. An eigenvalue method is ...

A semiautomatic ac/dc difference calibration system is described. The system operates overa frequency range of 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kV. For all voltages at frequencies in the range from 20 Hz to 20 kHz, the total uncertainty is 50 parts per million (ppm), and 100 ppm for voltages at frequencies between 20 kHz and 100 kHz. In addition to ...

This paper develops an incremental transformer model suitable for slow transient studies. A typical application is the study of temporary harmonic overvoltages in ac/dc systems caused by transformer saturation. The proposed model represents in detail the nonlinear magnetic circuit of the transformer and is, therefore, more complex than the piecewise linear models often used to simulate saturation. ...

An intense slow positron beam has been established at the 1-MW PULSTAR nuclear reactor. The beam is operational generating mono-energetic positrons with an energy of 1-keV. The maximum measured intensity slightly exceeds 109 e+/s. The beam is operated routinely with an intensity of approximately 5�108 e+/s. The positrons are generated through gamma-ray pair production interactions in two ...

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) instruments are capable of saving an entire mass spectrum at each pixel of an image, allowing for retrospective analysis of masses that were not selected for analysis during data collection. These TOF-SIMS spectral images contain a wealth of information, but few tools are available to assist the analyst in visualizing the entire raw data ...

This research focuses on the development scheme of a power converter in a gas engine cogeneration system using a power hardware-in-the-loop simulation. A matrix converter is adopted to substitute a conventional ac/dc/ac converter and transfers three phase electricity to single phase electricity directly. To ...

With the development of the superconducting magnet as an energy storage unit, pulsed power loads between superconducting magnets of increasing magnitude up to several hundred megawatts or more appear within the realm of possibility. An energy storage unit that is independent of the power grid can be used in applications where the pulsed power required from the power grid may cause a hazardous ...

Increasing complexity of high-voltage direct current (HVDC) transmission systems places new demands on alternating current/direct current (ac/dc) power converters. The possibility of using advanced power conversion techniques, specifically force-commutated conversion, is discussed. Previous work on this concept and some studies and development of ...

This paper presents a new control strategy for a three phase PWM converter, which consists of applying an adaptive nonlinear control. The input-output feedback linearization approach is based on the exact cancellation of the nonlinearity, for this reason, this technique is not efficient, because system parameters can vary. First a nonlinear system modelling is derived with ...

AC/DC adapters mostly employ two-stage topology: Power Factor Correction (PFC) pre-regulation stage followed by an isolated DC/DC converter stage. Low power AC/DC adapters require a small size to be competitive. Among their components, the bulk DC-link capacitor is one of the largest because it should keep the output voltage with low ...

Abstract�A new family of ac�dc converters is derived which integrate the functions of low-harmonic rectification, low-frequency energy storage, and wide-bandwidth output voltage control into a single converter containing one, two, or four active switches. These converters utilize a discontinuous conduction mode input inductor, an ...

In this paper, a transient voltage suppressor (TVS) using a native lateral back-to-back diode structure in conventional complementary metal-oxide-semiconductor (CMOS) technology is proposed. The capacitance, direct-current (DC) current-voltage (I-V) characteristics, and transmission line pulse (TLP) I-V characteristics of this lateral back-to-back diode ...

The series-resonant converter is one of the major classes of electronic power converters that are extensively applied in dc-dc conversion. This technology transfers bulk energy efficiently through a series-resonant circuit in the direct path of the energy transfer. This resonant converter forms a high-frequency ac link between the ...

Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC are related to in-medium mass-modification and squeezing of the quanta involved. Although the suppression of finite emission times were already known, the effects of finite system sizes and of ...

Positron identification in APEX is accomplished via the detection of the characteristic back-to-back 511 keV gamma rays emitted when the positrons annihilate in the APEX silicon array. The photons are detected in NaI arrays that surround the silicon arrays. To trigger APEX we designed and constructed the APEX Trigger Processor (ATP). The ATP provides a hardware trigger based ...

Back-to-back correlations of particle-antiparticle pairs are related to the in-medium mass-modification and squeezing of the quanta involved. They are predicted to appear when hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The survival and magnitude of the back-to-back correlations (BBC) of boson-antiboson pairs generated by in-medium mass ...

Simple changes in the chemistry, plumbing, and programming of the Siemens-CTI chemistry process control unit (CPCU) effectively double its output by enabling two back-to-back "1-pot" syntheses of 2-[18F]fluoro-2-deoxy-D-glucose in a single unit. Replacement of Kryptofix 2.2.2 with tetramethylammonium carbonate and elimination of diethyl ether from the procedure shorten ...

This thesis proposes and investigates application of a three-phase AC-AC Matrix Converter (MC), as an alternative to the conventional AC-DC-AC converter system, to interface a Micro-Turbine-Generator (MTG) unit as a Distributed Generation (DG) unit to a utility distribution grid. As compared with a conventional ...

Bidirectional dc current flow is not a natural feature of the buck (step-down) switch-mode rectifier, which leaves it at a disadvantage to boost (step-up) designs. A circuit topology is presented that allows bidirectional flow and which, by dual use of components, uses fewer devices than anti-parallel bridges. Sinusoidal current, controlled displacement factor, and variable voltage transfer ratio ...

During the spring of 1991, several severe geomagnetic disturbances were recorded in North America, and particularly in Northern Quebec, where Hydro-Quebec's La Grande generation complex and transmission system are located. As a result of these disturbances, the Quebec-New England Phase 2 HVDC system was affected by transformer saturation and harmonic voltage distortion due to geomagnetic ...

Abstract- Zero-current-transition, discontinuous-conduction-mode (ZCT-DCM) converters are intro-duced in this paper. Compared to hard-switching (PWM) converters in DCM, the ZCT-DCM con-verters have similar current stresses and conduction losses, and much reduced turn-off switching losses. At the expense of increased voltage stresses, ...

The Battery Energy Storage Test (BEST) Facility is a national center for testing and evaluating battery energy storage systems, including associated electrical conversion equipment developed for use on electric power grids. This interim report covers the period January 1980-June 1983 in which the following results were achieved: completed baseline facility construction including ac link to 13.8-kV ...

Apr 16, 2010 ... The reflector design incorporates two back-to-back off-axis Gregorian telescopes with 1.4 m x 1.6 m primary reflectors and 0.9 m x 1.0 m ...

Cameras for nuclear medicine imaging which use the two back-to-back gamma rays from a positron annihilation have the unique property of being able to give images of positron-emitting radionuclide distributions without the use of collimators and the associ...

In a world of expanding class sizes and shrinking budgets, it's rare to find a new teacher with his or her own classroom. New teachers often juggle multiple sections of multiple preps in different rooms--sometimes teaching back-to-back classes on different

Double ionization of Ar and Ne by 45 fs laser pulses (800 nm) has been explored at low intensities where ionization as a result of electron recollision is energetically not possible. We observe a strongly correlated back-to-back emission of the electrons along the polarization direction in striking contrast to all previous data at higher intensities and most calculations.

Internal structure and response to stretch of premixed laminar methane-air and propane-air flames are investigated numerically. The symmetrical 'back-to-back' flow configuration generated by two identical, counterflowing reactant streams is considered. Bo...

Simulated back-to-back shunt capacitor switching tests were conducted at the 230-kv Pinnacle Peak Substation, using 3 configurations of power circuits to represent the most likely modes of transient power circuit oscillations. Each circuit was impulsed wi...

An analysis is presented which demonstrates that a vertical multijunction solar cell with covering lens does have optimum dimensions. The analysis does point out that the optimum dimensions would indeed eliminate any dark junctions in series with illuminated junctions for maximum efficiency. Thus, back-to-back p-n junctions should not be designed into a solar cell. (AIP)

statistics Measurement method Avg. Std. dev. No. Duplicate samples measured back-to-back 0.9 0.68 64 One of sample. The method utilizes a multi-point hydrochloric acid titration of seawater according...............................................................................................................5 3. DESCRIPTION OF VARIABLES AND METHODS

This paper describes the SBS TDMA burst modem and presents bit error rate performance data measured over linear (IF back-to-back) and actual and simulated satellite channels. The simulated channel is briefly described and includes two TWTA's operated at or near saturation. The importance of tailoring the burst modem design to the channel nonlinearities is demonstrated. Plots ...

The coefficients that give the small angle (back-to-back) behavior of the energy-energy correlation function in e exp + e exp - annihilation are calculated at order alpha /sub s/ exp 2 from previous all order, small angle formulas. The purpose is to facil...

s network is simply two back�to�back butterfly networks. Waksman [47] gave an elegant linear time algorithm for determin� ing how the nodes should be set in order to realize any particular permuta� tion. Waksman�11 parallel computer. Waksman's algorithm, however, uses global knowledge of the permutation in order

A system for generating electricity contained within an ocean raft. The raft has a series of raceways for heavy metal balls, and, as they roll back and forth, they engage levers which reciprocate back-to-back paired pistons in opposite directions. Each pressurizing movement of a piston discharges a jet of fluid to a common pressure tank from which the pressurized fluid drives ...

A weak two-proton azimuthal angle back-to-back correlation which may indicate the presence of quasi-elastic first order proton-proton scattering in exp 16 O + CNO reactions at 2 GeV/nucleon has been observed. Low and medium multiplicity exp 16 O + AgBr re...

A new varactor diode process has been developed in which much of the processing is done from the back of an extremely thin semiconductor wafer laminated to a low-dielectric substrate. Back-to-back BNN diodes were fabricated with this technique; excellent ...

This paper presents discrete lens antenna array antennas developed for multi-beam communication applications. The lens arrays consist of two back- to-back arrays of antenna element pairs, connected by variable-length transmission lines, which allow the le...

The Florida Everglades, designated a National Park in 1947, comprise the largest area of wetlands and mangrove swamps in North America. In the late 1940s following back-to-back hurricanes, a massive flood-control project was instigated to construct levees...

This PDF document provides a menu of post-reading activities for students in grades 2-5. After reading a nonfiction or informational text, students select activities from the menu's categories to create a "well-balanced meal." This activity provides a means of differentiated instruction around a nonfiction text. The two-page document can be printed and copied back-to-back ...

Current density profile measurements were obtained in the Proto-Cleo Torsatron (R = 40 cm, a = 5 cm, l = 3, B/sub T/ = 3 kG, anti n approx. 10 exp 11 cm exp -3 , T/sub e/ approx. 20 eV) by using a small, back-to-back flat double probe. Three different ope...

The closed cycle hydrogen-oxygen proton exchange membrane (PEM) regenerative fuel cell (RFC) at the NASA Glenn Research Center has demonstrated multiple back-to-back contiguous cycles at rated power and round-trip efficiencies up to 52 percent. It is the ...

The nonsequential double ionization (NSDI) yield and final electron-electon correlation are examined for a laser wavelength of 800 nm over a wide range of laser intensities, using three-dimensional fully classical models. It is shown that in the transition region between NSDI and sequential ionization, turn-on stage recollisions can lead to having a majority of anticorrelated ...

University of Science and Technology. All rights reserved. Hans van Leeuwen Around campus Cure for Parkinson. Innovator of the year ISU's Hans van Leeuwen, whose research teams earned back-to-back R&D 100 awards The Knoll, 0.2 mwh Wind energy awareness messages will be integrated into radio interviews, videoboard clips

convergent orogens consist of two wedges, arranged back-to-back. This idea was first proposed for colli:27 PM Page 572 #12;In the Olympics, the structural lid has slowly been driven into the back of the wedge- vergence velocity). It is more common to consider the 22.2 THE CASCADIA SUBDUCTION WEDGE: THE ROLE

the non{ aring Sun. In fact, ares emit higher energy X{rays (as can be seen also in Figure 3 (bottom inside the Sun, their thermal energy peaks at #24; 4:2 keV and they are ultra-relativistic. They mostly Following the decay mode a ! , the two photons have the same energy and are emitted back{to{back, because

... b. Fluke 803B AC/DC Differential Voltmeter, Serial number 2797- c. Fluke 823A AC/DC Differential Voltmeter, Serial number 274. ...

... AC/DC, demmies, dillies, hillbilly heroin, oxy, percs, vics � whatever you call prescription pain relievers, always remember they can be killers when misused ...

... Accession Number : ADA211612. Title : Investigation of Resonant AC-DC Magnetic Field Effects. Descriptive Note : Final rept. May 1986-Jul 1989. ...

... Search, All Collections, ... Title : Electronic-Commutator AC/DC Motor-Driven Tracked All-Terrain Vehicles with Extremely High Mobility,. ...

This website serves as an excellent tutorial on basic AC & DC electronics, semiconductor operation and digital theory. Experiments are included to illustrate these concepts. The material is sufficiently comprehensive and is highly recommended as a starting point for students interested in learning about basic electronics.

The procedure describes the calibration of the Radio Frequency Laboratories, Inc. Model 33 AC-DC- Meter Calibrator. The test instrument is a self contained unit providing accurate av, dv, ac, or dc outputs. (Author)

A low-ripple diode charge-pump type AC-DC converter based on the Cockcroft-Walton diode multiplier is proposed for coilcoupled passive IC tags in this paper. This circuit is developed as a power supply for passive RFID tags with smart functions such as heart rate detection and/or body temperature measurement. The proposed circuit ...

... heat sinking of the electronic components was ... conception of the mechanical packaging was established. ... not react instantaneously to short circuits. ...

... CIRCUITS, COMPUTER PROGRAMMING, SEMICONDUCTOR DEVICES, ALTERNATING CURRENT, DIRECT CURRENT, TRANSIENTS, LOGIC ...

The Power Sources Manufacturers Association (PSMA) is pleased to announce the release of the latest Power Technology Roadmap Workshop Report. This Fifth Edition Workshop Report includes presentations and discussions from the workshop as seen by the participants that included many of the industry's most influential members representing end-users, power supply manufacturers, component ...

In this dissertation, two major accomplishments are achieved. First, the feasibility of a proposed Wyoming to California HVDC system having the ratings of 1000 MW, �500 kV, 2 kA, 860 miles and 12-pulse bipolar lines is shown for exporting Wyoming's electrical power resources to the heavy loaded western states. The second and the main objective of this dissertation is the development of a Kalman ...

Details are reported on the initial stages of engineering reference designs for 10-MWh and 10/sup 4/-MWh SMES units, and the design and status of a 100-MJ (28-kWh) SMES experiment. Several superconducting wires have been evaluated in 300-mm-i.d. coils. In these tests cables and braids consistently performed better than a monolithic conductor. Special circuits designed to detect ...

Line harmonics are usually predetermined under the simplified assumption that the dc current is sufficiently smoothed. However, in practical operation of controlled converters, e.g., feeding medium-size dc drives, it frequently happens that the dc ripple cannot be neglected. For the predetermination of line harmonics, this means that the operating point is specified by the emf ...

The power system dynamic instability problem on the Pacific AC/DC Intertie was solved by modulating the converter power of the HVDC tie line. An alternate control approach using magnetic energy storage is explored for more general power systems without HVDC lines. Dynamic equivalents of power systems are first formulated using a component connection model ...

This is a technical summary report of the 60 T controlled power research magnet that was designed, assembled, installed and recently commissioned at the National High Magnetic Field Laboratory (NHMFL) Pulsed Field Facility at Los Alamos National Laboratory. The magnet is a innovative in its design, construction, size, operation and power supply. The magnet consists of nine nested, mechanically ...

The feasibility for implementation of a concept for direct ac/dc multikilowatt power conversion with bidirectional transfer of energy was investigated. A 10 kHz current carrier was derived directly from a common 60 Hz three phase power system. This carrier was modulated to remove the 360 Hz ripple, inherent in the three phase power supply and then demodulated and processed by ...

Three phase ac/dc/ac converters operating with reduced reactive elements have been investigated in this work. It has been determined that the voltage sourced converter circuit topology results in a lower reactive element cost than a current sourced converter, independent of the switching strategy. With the topology ...

The objective of this study is to develop a parallel ac-ac converter that can be implemented as a means of connecting ac generators in parallel. The most important goal of the parallel converter in this study is to obtain equal current sharing performance among the paralleled generators such that an economically optimal solution for production cost of ...

In order to develop improved standards for the measurement of ac voltages and currents, a new thin-film fabrication technique for the multijunction thermal converter has been developed. The ability of a thermal converter to relate an rms ac voltage or current to a dc value is characterized by a quantity called `ac-dc difference' that ...

Sandia, Los Alamos, and Lawrence Livermore National Laboratories currently deploy high speed, Wide Area Network links to permit remote access to their Supercomputer systems. The current TCP congestion algorithm does not take full advantage of high delay, large bandwidth environments. This report involves evaluating alternative TCP congestion algorithms and comparing them with the currently used ...

This paper presents the design and the fabrication of two low-loss X-band back-to-back tunable ferroelectric resonator filters on flexible liquid crystal polymer substrates using wire-bonded BST capacitors as analog tuning elements. The back-to-back topology consists of three resonators on both sides of the substrate coupled by apertures in their common ground plane, allowing ...

Ripple currents on the DC side of both HVDC synchronous and asynchronous. Links together with cleared HVDC and AC system disturbances can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC Link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales ...

Two widely proposed kt-dependent gluon distributions in the small-x saturation regime are investigated using two-particle back-to-back correlations in high energy scattering processes. The Weizs�cker-Williams gluon distribution, interpreted as the number density of gluon inside nucleus, is studied in the quark-antiquark jet correlation in deep inelastic scattering. On the ...

Two widely proposed k(t)-dependent gluon distributions in the small-x saturation regime are investigated using two-particle back-to-back correlations in high energy scattering processes. The Weizs�cker-Williams gluon distribution, interpreted as the number density of gluon inside nucleus, is studied in the quark-antiquark jet correlation in deep inelastic scattering. On the ...

The crystal structure of Escherichia coli GroEL shows a porous cylinder of 14 subunits made of two nearly 7-fold rotationally symmetrical rings stacked back-to-back with dyad symmetry. The subunits consist of three domains: a large equatorial domain that forms the foundation of the assembly at its waist and holds the rings together; a large loosely structured apical domain ...

We present a phenomenological study of the single-transverse spin asymmetry in azimuthal correlations of two jets produced nearly 'back-to-back' in pp collisions at RHIC. We properly take into account the initial- and final-state interactions of partons that can generate this asymmetry in QCD hard-scattering. Using distribution functions fitted to the ...

The production process anti p p ..-->.. l/sup -/l'/sup +/ + X, where the leptons belong to two different generations and X refers to spectator jets, provides a clear signature for horizontal (generation-changing) bosons when the leptons are emitted nearly back-to-back and p/sub T//sup miss/ = 0. Cross sections and p/sub T/ distributions for each lepton are ...

Katrina 1,453,000 8 Wilma 3,241,437 18 2005 Season Tropical storm force winds Hurricane force winds Storm Season 2004-2005 7 Storms / 15 Months 2 #12;Florida Power & Light 2004 - 2005 Record Breaking Storm Seasons � 2004 was unprecedented � 3 back-to-back storms within 36 days � Nearly 47,000 workers from 39 states

Using a metal-semiconductor-metal back-to-back Schottky contacted ZnO microwire device, we have demonstrated the piezoelectric effect on the output of a photocell. An externally applied strain produces a piezopotential in the microwire, which tunes the effective height of the Schottky barrier (SB) at the local contact, consequently changing the transport characteristics of the ...

Conventional video cameras have limited fields of view that make them restrictive in a variety of vision applications. There are several ways to enhance the field of view of an imaging system. However, the entire imaging system must have a single effective viewpoint to enable the generation of pure perspective images from a sensed image. A camera with a hemispherical field of view is ...

The fission cross section of Pu/sup 240/ was determimed from Pu/sup 240/U/sup 235/ ratio for neutron energies between threshold and 8.1 Mev. U/sup 235/ cross section values were essentially those given in a recent compilation in ''Progress in Nuclear Energy.'' The technique used was to mount the two foils back-to-back in a double ionization ...

This paper explains how first-year composition students wrote business sales letters about short fiction and then revised those letters into full-fledged literary essays that analyzed the stories. By completing these two writings back-to-back (that is, experiencing the metagenres between business writing and literary analysis), students not only see that disciplines are linked ...

tantalum discs0.5- 1cm in diameter. Occasionally, double-sided (back-to- back) Langmuir probes are used of theelectron flux fromthetarget plasmatoward the driverwere obtained using adouble-sidedLangmuir probe in which of the double layer. Theelectrontemperatureswereobtained using the double-sidedLangmuir probe, while the ion

Searches have been made for the ?+/electron-capture-type double decays of 50Cr, 64Zn, 92Mo, and 96Ru and for the double ?+ decay of 96Ru. The sought-for signature of such decays was the emission of coincident back-to-back 511-keV annihilation gamma rays from the sample under study. No positive evidence of any of these decays was observed. However, from these experiments, ...

We study the dihadron azimuthal correlation produced nearly back-to-back in unpolarized hadron collisions, arising from the product of two Collins fragmentation functions. Using the latest Collins fragmentation functions extracted from the global analysis of available experimental data, we make predictions for the azimuthalcorrelation of two-pion production in pp collisions at ...

Published in English and Arabic back�to�back, this book explains the concepts and procedures of verification and compliance in arms control and disarmament agreements. It examines the position of the United Nations as a mediator, and it details forms of verification, including on�site inspections and satellite observations, using the Strategic Arms Reduction Treaty ...

The power modulation of a high voltage direct current (HVDC) system for stabilization of an ac/dc network was investigated. It was found that simultaneous modulation of both dc current and voltage was more effective than just current modulation by itself, since the dc voltage modulation could be used to minimize the reactive power changes resulting from a change of the dc current. This helps ...

The basic problem investigated is as follows: assume a system where the sending end and receiving end are separated by a transmission line of length lambda which is loaded to some practical level, say surge impedance loading. A disturbance occurs somewhere in the load area and this load is dumped by opening a circuit breaker at the receiver end low voltage terminals. The interaction of the ...

In present work, a ring-type unipoled step-down piezoelectric transformer with the dimensions of ?16�0.7 mm3 was designed and fabricated using relaxor ferroelectric single crystal (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT). Both the input and output parts of this transformer were poled along the thickness direction, utilizing the radial vibration mode of PMN-PT. The electrical measurement results ...

Nanotech approaches were explored for the efficient transformation of an electrical signal into sound, heat, cooling action, and mechanical strain. The studies are based on the aligned arrays of multi-walled carbon nanotubes (MWNT forests) that can be grown on various substrates using a conventional CVD technique. They form a three-dimensional conductive network that possesses uncommon electrical, ...

Power harvesting refers to the practice of acquiring energy from the environment which would be otherwise wasted and converting it into usable electric energy. Much work has been done on studying the optimal AC power output, while little has considered the AC-DC output. This article investigates the optimal AC-DC power generation for a rectified ...

A thyristor-based inverter/charger for use in electric passenger vehicles is described, and prototype charger test results are presented. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The integral charger employs the inverter commutation components as a resonant ac/dc converter rated at ...

APL has three existing series resonant inverter-based power converters: Power--10kW, 5kW, 200kW, Topology--dc/dc 1/2 Bridge, ac/dc Full Bridge, dc/dc Dual Full Bridge, the control and protection circuits are different for the three units. The purpose of this program was to produce a control and protection architecture and functional circuits that would ...

The fabrication of monolithically integrated configurations of semiconductor lasers incorporating multiple functions is still an open issue today in engineering. A useful set of functions to integrate are: surface-emitting, high -power, phase-locked, single-mode, and collimated laser beam output. In this work new materials and advanced fabrication processes are developed for integrating the first ...

This report contains a work statement for a study in which the objective is to examine the dynamic relationships of integrated ac/dc power systems containing high voltage direct current circuit breakers; a one-page discussion of the effects of a planned HVDC system on interconnected ac systems located in the general vicinity; and a quarterly progress report for a study aimed ...

... Operational Requirements Document (ORD) for the Alternating Current/Direct Current (AC/DC) Clamp-on CARDS ORD 16039 ...

... Title : Operational Requirements Document (ORD) for the Alternating Current/ Direct Current (AC/DC) Clamp-on Ammeter, ME-563. ...

The most cost-effective AC/DC and DC systems are evaluated, specifically to develop system details which lead to technology goals, including: array; ...

... We chose planar black lipid mem- branes for experimental studies of magnetic field effects on membranes because they are the simplest known ...

... DC propulsion systems using silicon rectifier conversion equipment with the following objectives: Discussion of the AC - DC propulsion system with ...

... Title : Hardware Model of a Shipboard Zonal Electrical Distribution System (ZEDS): Alternating Current/Direct Current (AC/DC). ...

... Title : Hardware Model Of A Shipboard Zonal Electrical Distribution System (ZEDS): Alternating Current/Direct Current (AC/DC). ...

... of the dry disk brake on the induction motor is ... ME AC DC), and the DC generator (ME DC ... DC generators can take three basic forms; a commutated ...

Build circuits with capacitors, inductors, resistors and AC or DC voltage sources, and inspect them using lab instruments such as voltmeters and ammeters.

This new version of the CCK adds capacitors, inductors and AC voltage sources to your toolbox! Now you can graph the current and voltage as a function of time.

... Characterizing the degradation of Army primers by the AC-DC-AC accelerated test method ... DC AC-DC-AC accelerated testing method Page 5. ...

... SUPPLIES), (*RADAR TRANSMITTERS, (*PHASED ARRAYS, POWER SUPPLIES), ALTERNATING CURRENT, DIRECT CURRENT, CIRCUITS ...

... air-cooling function of the air-conditioning system is ... An air conditioner that is capable of supplying a ... ohm multimeters; one differential ac-dc vacuum ...

Variable frequency drives typically have employed dc voltage or current links for power distribution between the input and output converters and as a means to temporarily store energy. The dc link based power conversion systems have several inherent limitations. One of the important limitations is the high switching loss and high device stress which occur during switching ...