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1

Voltage regulation system design for the four-wire voltage-converter with split DC link capacitor  

Microsoft Academic Search

This paper presents the voltage regulation system design for the four-wire voltage converter with split DC link capacitor. The voltage regulation system is used to control the DC side voltages on a three-leg voltage source converter connected to the AC mains. It accomplishes the total DC voltage regulation and voltage sharing across capacitors. System modelling and compensators syntheses are realized

V. Soares; P. Verdelho

2002-01-01

2

EXPERIMENTS WITH A DC WIRE IN RHIC  

SciTech Connect

A DC wire has been installed in RHIC to explore the long-range beam-beam effect, and test its compensation. We report on experiments that measure the effect of the wire's electro-magnetic field on the beam's lifetime and tune distribution, and accompanying simulations.

FISCHER,W.; CALAGA, R.; DORDA, U.; KOUTCHOUK, J.-P.; ZIMMERMANN, F.; SEN, T.

2007-06-25

3

Topology for Current Balancer with Half-Bridge Inverters in Single-Phase Three-Wire Distribution Systems with DC-Capacitor-Voltage Balancer  

NASA Astrophysics Data System (ADS)

This paper proposes a new topology for a current balancer with half-bridge inverters in single-phase three-wire distribution systems with a three-leg inverter. Two half-bridge inverters are connected to the sources. The midpoint of two capacitors on the DC-side is connected to a neutral line. The two half-bridge inverters perform a current balancer for single-phase three-wire distribution systems by exchanging the active and reactive power on the each feeder through the two DC-capacitors. The third-leg performs a DC-capacitor-voltage balancer for the two DC-capacitors connected to the half-bridge inverters. Thus, balanced source voltages and currents are obtained on the secondary-side on the pole-mounted distribution transformer with balanced DC-capacitor voltages. The basic principle of the proposed current balancer is discussed in detail, and then, confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results show that balanced source voltages and currents are obtained on the secondary-side on the pole-mounted distribution transformer with balanced DC-capacitor voltages.

Baba, Yusuke; Sugahara, Kazuya; Okamoto, Masayuki; Hiraki, Eiji; Tanaka, Toshihiko

4

A Constant DC Voltage Control Based Strategy for the Current Balancer in Single-Phase Three-Wire Secondary Distribution Systems  

NASA Astrophysics Data System (ADS)

This paper deals with applying the constant dc voltage control based algorithm to the current balancer in single-phase three-wire secondary distribution systems. The power flows into a three-leg inverter, which performs the current balancer, are discussed, and then we show that only the reactive power flows into the three-leg inverter. This demonstrates that the required-capacity of the dc capacitor can be reduced as compared to that of the active power quality compensator used in the electrified railways. This reduced-capacity dc capacitor results in the rapid and stable balancing. The basic principle of the proposed method is discussed in detail, and then confirmed by digital computer simulation. Digital computer simulation results demonstrate that the balanced source currents with unity power factor are obtained remaining the unbalanced load currents conditions.

Fukui, Hirokazu; Hiraki, Eiji; Tanaka, Toshihiko

5

LANSCE-R WIRE-SCANNER SYSTEM  

SciTech Connect

The National Instruments cRIO platform is used for the new LANSCE-R wire-scanner systems. All wire-scanner electronics are integrated into a single BiRa BiRIO 4U cRIO chassis specifically designed for the cRIO crate and all interface electronics. The BiRIO chassis, actuator and LabVIEW VIs provide a complete wire-scanner system integrated with EPICS. The new wire-scanner chassis includes an 8-slot cRIO crate with Virtex-5 LX 110 FPGA and Power-PC real-time controller, the LANL-developed cRIO 2-axis wire-sensor analog interface module (AFE), NI9222 cRIO 4-channel 16-bit digitizer, cRIO resolver demodulator, cRIO event receiver, front-panel touch panel display, motor driver, and all necessary software, interface wiring, connectors and ancillary components. This wirescanner system provides a complete, turn-key, 2-axis wire-scanner system including 2-channel low-noise sensewire interface with variable DC wire bias and wireintegrity monitor, 16-bit signal digitizers, actuator motor drive and control, actuator position sensing, limit-switch interfaces, event receiver, LabVIEW and EPICS interface, and both remote operation and full stand-alone operation using the touch panel.

Gruchalla, Michael E. [Los Alamos National Laboratory

2011-01-01

6

Robust 300 C wire insulation system  

NASA Astrophysics Data System (ADS)

The objective of this program is to identify, develop, and demonstrate an optimum wire insulation system that is capable of continuous operation at 300 C. The system is to possess a combination of superior electrical (AC or DC), mechanical, and physical properties over the KAPTON (trademark) derived insulations described in MIL-W-81381 and those hybrid constructions identified in Air Force contract F33615-89-C-5606, commonly known as TKT constructions.

Nairus, John G.

1994-01-01

7

Magnesium diboride wire application to high power superconducting dc cables  

NASA Astrophysics Data System (ADS)

In 1967, R. L. Garwin and J. Matisoo considered the possibility of constructing a 100 GW, 1000 km, dc superconducting transmission line based on the then newly discovered type II material, Nb_3Sn, refrigerated by liquid helium at 4.2 K.^1 Their paper is viewed by many as the seminal study on the practicality of superconductivity for use in electric transmission cables, and influenced the design of the high temperature superconducting cables now undergoing demonstration worldwide refrigerated by liquid nitrogen, although at much lower power capacities due to the high cost of high temperature superconducting wire. However, the recent discovery of the 39 K MgB2 superconductor and its promise of cheap, high performance wire may enable the multi-gigawatt capacity transmission line Garwin-Matisoo envisioned. In this presentation, we will rescale their study for MgB2 cooled by liquid hydrogen at 21 K, which will be used as an additional energy delivery agent as well as a cryogen. ^1R. L. Garwin and J. Matisoo, Proc. IEEE 55, 538 (1967).

Grant, Paul M.

2003-03-01

8

Establishment of a Switched-Reluctance Generator-Based Common DC Microgrid System  

Microsoft Academic Search

This paper presents a dc microgrid including a switched-reluctance generator (SRG) with isolated boost dc-dc converter, a battery energy storage system, and a single-phase three-wire (1P3W) load inverter for generating ac 220\\/110 V 60-Hz outputs. The 400-V dc grid is established by the SRG with dc 48-V output followed by a current-fed push-pull (CFPP) dc-dc converter. The robust commutation and

Yuan-Chih Chang; Chang-Ming Liaw

2011-01-01

9

A Prototype Wire Position Monitoring System  

SciTech Connect

The Wire Position Monitoring System (WPM) will track changes in the transverse position of LCLS Beam Position Monitors (BPMs) to 1{micro}m over several weeks. This position information will be used between applications of beam based alignment to correct for changes in component alignment. The WPM system has several requirements. The sensor range must be large enough so that precision sensor positioning is not required. The resolution needs to be small enough so that the signal can be used to monitor motion to 1{micro}m. The system must be stable enough so that system drift does not mimic motion of the component being monitored. The WPM sensor assembly consists of two parts, the magnetic sensor and an integrated lock-in amplifier. The magnetic sensor picks up a signal from the alternating current in a stretched wire. The voltage v induced in the sensor is proportional to the wire displacement from the center of the sensor. The integrated lock-in amplifier provides a DC output whose magnitude is proportional to the AC signal from the magnetic sensor. The DC output is either read on a digital voltmeter or digitized locally and communicated over a computer interface.

Wang, Wei

2010-12-07

10

Fly-by-Wire Flight Control Systems.  

National Technical Information Service (NTIS)

The purpose of this paper is to provide the reader with an introduction to fly-by-wire and an outline of state-of-the-art fly-by-wire techniques. An outline of the philosophy of fly-by-wire flight control systems is given, the evolution of fly-by-wire is ...

J. P. Sutherland

1967-01-01

11

Calculation of ozone generation by positive dc corona discharge in coaxial wire-cylinder reactors  

NASA Astrophysics Data System (ADS)

A theoretical equation has been derived in this paper for calculation of ozone generation by positive dc corona discharge in coaxial wire-cylinder reactors. The derived equation has been based on the theories of the positive dc coronas reported in the literature and extended to account the ozone destruction within the corona discharge plasma generated in the reactor. The equation has been investigated with experimental results for ozone generated in a coaxial wire-cylinder reactor under different discharge conditions. The reactor was stressed with a positive dc voltage and fed by dry air flowing with constant rates at atmospheric pressure and room temperature. The theoretical results calculated by the derived equation have shown good agreement with the experimental results over the whole range of the investigated parameters. Subsequently, the derived equation is valid to predict the ozone concentration generated in the investigated reactor under any discharge conditions.

Yehia, Ashraf

2007-01-01

12

Unbalanced power active compensator with unit efficiency control for the improvement of the electric quality in four wire systems with photovoltaic panels in the DC bus  

Microsoft Academic Search

The paper presents a new method for obtaining the reference currents for an unbalanced power active compensator (UPAC), applied in unbalanced systems with linear loads connected to an unbalanced three-phase system and with positive sequence voltage. The reference currents are obtained using the unifying theory of electrical power (UTEP). UTEP is applied to the control of a power converter and

Salvador Segui; Francisco Gimeno; Vicente Leon; J. Montanana

2002-01-01

13

Modeling and analysis of DC distribution systems  

Microsoft Academic Search

Research on modification and replacement of conventional AC distribution system to DC is widely undergoing. When DC distribution is applied in a system with DC-preferred appliances, it is possible to enhance energy consumption efficiency by reducing conversion losses. Moreover, renewable energy sources and storage devices can be fully utilized because they are more compatible with DC based system where generated

Gab-Su Seo; Jongbok Baek; Kyusik Choi; Hyunsu Bae; Bohyung Cho

2011-01-01

14

SpaceWire Data Handling Demonstration System  

NASA Astrophysics Data System (ADS)

The SpaceWire standard was published in 2003 with the aim of providing a standard for onboard communications, defining the physical and data link layers of an interconnection, in order to improve reusability, reliability and to reduce the cost of mission development. The many benefits which it provides mean that it has already been used in a number of missions, both in Europe and throughout the world. Recent work by the SpaceWire community has included the development of higher level protocols for SpaceWire, such as the Remote Memory Access Protocol (RMAP) which can be used for many purposes, including the configuration of SpaceWire devices. Although SpaceWire has become very popular, the various ways in which it can be used are still being discovered, as are the most efficient ways to use it. At the same time, some in the space industry are not even aware of SpaceWire's existence. This paper describes the SpaceWire Data Handling Demonstration System that has been developed by the University of Dundee. This system simulates an onboard data handling network based on SpaceWire. It uses RMAP for all communication, and so demonstrates how SpaceWire and standardised higher level protocols can be used onboard a spacecraft. The system is not only a good advert for those who are unfamiliar with the benefits of SpaceWire, it is also a useful tool for those using SpaceWire to test ideas.

Mills, S.; Parkes, S. M.; O'Gribin, N.

2007-08-01

15

A Vibrating Wire System For Quadrupole Fiducialization  

SciTech Connect

A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization step of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our method of choice. We then give an overview of the measurement system showing how the vibrating wire is positioned onto the quadrupole axis, how the wire position detectors locate the wire relative to tooling balls without touching the wire, and how the tooling ball positions are all measured. The novel feature of this system is the vibrating wire which we discuss in depth. We analyze the wire dynamics and calculate the expected sensitivity of the system. The note should be an aid in debugging the system by providing calculations to compare measurements to.

Wolf, Zachary

2010-12-13

16

Bidirectional DC to DC converters for fuel cell systems  

Microsoft Academic Search

This paper first describes the need of a bi-directional DC to DC converter for a fuel cell system. Various combinations of current-fed and voltage-fed converters are explored for the application of different voltage levels. With a preliminary study, putting current-fed on low-voltage side and voltage fed on high voltage side indicated higher efficiency than the other way around. Two low-side

K. Wang; C. Y. Lin; L. Zhu; D. Qu; F. C. Lee; J. S. Lai

1998-01-01

17

The analysis and simulation to the add-in DC reverse testing pulse based current-leakage protection method for DC trolley system  

Microsoft Academic Search

Based on the analysis to various current-leakage protection methods for DC trolley system, especially to the method based on add-in AC testing signal, a research on a new current-leakage protection method for DC trolley system based on add-in DC-reverse testing pulse is presented. Considering of the effects of four distributing parameters of the long wire, i.e. line inductance L, line

Cheng Hong; Wang Cong; Lu Qi-wei; Wang Dong-hua

2008-01-01

18

Photovoltaic DC-DC converter for telecommunications energy systems  

Microsoft Academic Search

Standalone power systems are becoming a suitable way of supplying telecommunications equipment, since they are being located in remote areas, which seems to be its nowadays and future trend location. Power electronics interfaces play an important role in these systems, because they are responsible for meeting load supply requirements. Photovoltaic (PV) generators are nonlinear sources, and behave mainly as DC

E. F. F. Ribeiro; A. J. Marques Cardoso; C. Boccaletti; A. M. S. Mendes

2009-01-01

19

A pseudodifferential amplifier for bioelectric events with DC-offset compensation using two-wired amplifying electrodes.  

PubMed

Most wired active electrodes reported so far have a gain of one and require at least three wires. This leads to stiff cables, large connectors and additional noise for the amplifier. The theoretical advantages of amplifying the signal on the electrodes right from the source has often been described, however, rarely implemented. This is because a difference in the gain of the electrodes due to component tolerances strongly limits the achievable common mode rejection ratio (CMRR). In this paper, we introduce an amplifier for bioelectric events where the major part of the amplification (40 dB) is achieved on the electrodes to minimize pick-up noise. The electrodes require only two wires of which one can be used for shielding, thus enabling smaller connecters and smoother cables. Saturation of the electrodes is prevented by a dc-offset cancelation scheme with an active range of +/- 250 mV. This error feedback simultaneously allows to measure the low frequency components down to dc. This enables the measurement of slow varying signals, e.g., the change of alertness or the depolarization before an epileptic seizure normally not visible in a standard electroencephalogram (EEG). The amplifier stage provides the necessary supply current for the electrodes and generates the error signal for the feedback loop. The amplifier generates a pseudodifferential signal where the amplified bioelectric event is present on one lead, but the common mode signal is present on both leads. Based on the pseudodifferential signal we were able to develop a new method to compensate for a difference in the gain of the active electrodes which is purely software based. The amplifier system is then characterized and the input referred noise as well as the CMRR are measured. For the prototype circuit the CMRR evaluated to 78 dB (without the driven-right-leg circuit). The applicability of the system is further demonstrated by the recording of an ECG. PMID:16485759

Degen, Thomas; Jäckel, Heinz

2006-02-01

20

Prediction on future DC power system  

Microsoft Academic Search

Analyzed some serious issues, including power energy quality and large area power interruption, require complex method to overcome in 3-phase power system, so, suggested to go other way, proposed independent full DC power system to become one of main power systems in the future. The authors emphasized the necessity and capability of full DC power systems in the significance of

Qianzhi Zhou; Defang Yuan

2009-01-01

21

Particle in cell modelling of the observed modes of a dc wire discharge  

NASA Astrophysics Data System (ADS)

Low-pressure dc wire induced plasma sources exhibit two stable modes of discharge—constricted below a threshold pressure and diffuse above. Starting from experimental measurements, we conduct two-dimensional particle in cell (PIC) modelling of a dc low-pressure (10-4-10-2 mbar), low-current (~1 mA) wire discharge in helium. 2D PIC modelling is required to capture longitudinal non-uniformity of the diffuse mode. PIC simulations reproduce the two discharge modes. The voltage versus pressure curve obtained from simulations matches fairly well the experimental data, including the transition region. Discharge voltage dependence on pressure is analysed in consideration of electron impact ionization rates' evolution with energy. In light of the PIC findings, a model of the discharge mode transition based on the Child-Langmuir theory for ions is proposed. Confrontation with simulated data shows good agreement and validates the model for mode transition prediction. Simulations show that the diffuse mode is a space-charge-dominated regime.

Gueroult, R.; Elias, P. Q.; Packan, D.; Bonnet, J.; Rax, J. M.

2010-09-01

22

A DC-DC converter adequate for alternative supply system applications  

Microsoft Academic Search

The proposed DC-DC system introduced in this work provides output voltage regulation and control of energy flow between a battery bank and the output DC bus. A simple structure, composed by a DC-DC converter and a battery energy storage, is able to compensate power and voltage fluctuations in supply grid and to provide protection against power outages. The proposed system

V. M. Pacheco; L. C. Freitas; E. A. A. Coelho; V. J. Farias

2002-01-01

23

A Bidirectional DC–DC Converter for an Energy Storage System With Galvanic Isolation  

Microsoft Academic Search

This paper addresses a bidirectional dc-dc converter suitable for an energy storage system with an additional function of galvanic isolation. An energy storage device such as an electric double layer capacitor is directly connected to a dc side of the dc-dc converter without any chopper circuit. Nevertheless, the dc-dc converter can continue operating when the voltage across the energy storage

Shigenori Inoue; Hirofumi Akagi

2007-01-01

24

A FLYING WIRE SYSTEM IN THE AGS.  

SciTech Connect

As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

1999-03-29

25

LANSCE Wire Scanner System Prototype: Switchyard Test  

SciTech Connect

On November 19, 2011, the beam diagnostics team of Los Alamos National Laboratory's LANSCE accelerator facility conducted a test of a prototype wire scanner system for future deployment within the accelerator's switchyard area. The primary focus of this test was to demonstrate the wire scanner control system's ability to extend its functionality beyond acquiring lower energy linac beam profile measurements to acquiring data in the switchyard. This study summarizes the features and performance characteristics of the electronic and mechanical implementation of this system with details focusing on the test results.

Sedillo, James D [Los Alamos National Laboratory

2012-04-11

26

A novel flying hot-wire system  

Microsoft Academic Search

A new flying hot-wire system has been developed for the measurement of highly turbulent and reversing flows. The apparatus is of rectilinear design, incorporating many features which extend its range of application beyond the range of previous designs. One of the advantages of this system is that it is mounted on a flow visualization wind tunnel which allows complementary qualitative

R. M. Kelso; T. T. Lim; A. E. Perry

1994-01-01

27

Reliable study of digital IC circuits with margin voltage among variable DC power supply, electromagnetic interference and conducting wire antenna  

Microsoft Academic Search

This paper measures the margin voltage of a digital IC circuit in order to assess the deterioration of the margin voltage caused by variations in the DC power supply, electromagnetic interference (EMI), and the corresponding power induced in a conducting wire antenna (CWA). The present results confirm that these factors may influence the margin voltage to such an extent that

Han-chang Tsai

2003-01-01

28

Wiring specificity in the olfactory system.  

PubMed

The fruitfly brain learns about the olfactory world by reading the activity of about 50 distinct channels of incoming information. The receptor neurons that compose each channel have their own distinctive odour response profile governed by a specific receptor molecule. These receptor neurons form highly specific connections in the first olfactory relay of the fly brain, each synapsing with specific second order partner neurons. We use this system to discuss the logic of wiring specificity in the brain and to review the cellular and molecular mechanisms that allow such precise wiring to develop. PMID:16439169

Jefferis, Gregory S X E; Hummel, Thomas

2006-01-24

29

Neutral Current of an Edison Wire System  

NSDL National Science Digital Library

This is an object learning lesson, created by Terry Bartelt of the Wisconsin Online Resource Center, on neutral current of an Edison wire system. The employment of Flash allows users to interact with the presentation. Overall, this is a nice introduction to this specific topic.

Bartelt, Terry L.

2010-09-23

30

DC-DC converter-aware power management for battery-operated embedded systems  

Microsoft Academic Search

Most digital systems are equipped with DC-DC converters to supply various levels of voltages from batteries to logic devices. DC-DC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of DC-DC converters is changed by the output voltage level and the load current, most existing power management techniques simply

Yongseok Choi; Naehyuck Chang; Taewhan Kim

2005-01-01

31

DC-DC Converter-Aware Power Management for Low-Power Embedded Systems  

Microsoft Academic Search

Most digital systems are equipped with dc-dc converters to supply various levels of voltages from batteries to logic devices. DC-DC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of dc-dc converters is changed by the output voltage level and the load current, most existing power management techniques simply

Yongseok Choi; Naehyuck Chang; Taewhan Kim

2007-01-01

32

USAF/WL robust 300 C wire insulation system program status  

NASA Astrophysics Data System (ADS)

The objective of this program is to identify, develop, and demonstrate an optimum wire insulation system capable of continuous operation at 300 C which possesses a combination of superior electrical (AC or DC), mechanical, and physical properties over Kapton derived insulations described in MIL-W-81381 and those hybrid materials commonly known as TKT constructions.

Wong, Wing

1995-11-01

33

Performance of single-phase DC drive system controlled by uniform PWM full-bridge DC-DC converter  

Microsoft Academic Search

DC drive systems controlled by pulse-width modulation (PWM) techniques are expected to replace the conventional phase-controlled systems. This is due to their simple control, high reliability, low cost and fast response. This paper presents the performance of a single-phase DC drive system controlled by uniform PWM full-bridge DC-DC converter. Two different uniform PWM control techniques are considered; PWM with bipolar

T. H. Abdelhamid

2000-01-01

34

DC-DC converter-aware power management for battery-operated embedded systems  

Microsoft Academic Search

Most digital systems are equipped with DC-DC converters to supply various levels of voltages from batteries to logic devices. DCDC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of DC-DC converters is changed by the output voltage level and the load current, most existing power management techniques simply

Yongseok Choi; Naehyuck Chang; Taewhan Kim

2005-01-01

35

Parallel Operation of DFIGs in Three-Phase Four-Wire Autonomous Wind Energy Conversion System  

Microsoft Academic Search

This paper deals with a control algorithm for two parallel-operated doubly fed induction generators (DFIGs) driven by wind turbines in a three-phase four-wire autonomous system feeding local loads. The proposed autonomous wind energy conversion system (AWECS) is using back-to-back-connected pulsewidth-modulated insulated-gate-bipolar-transistor-based voltage source converters with a battery energy storage system at their dc link. The system utilizes separate rotor-side converters

Puneet K. Goel; Bhim Singh; S. S. Murthy; Navin Kishore

2011-01-01

36

AC/DC Smart Control And Power Sharing of DC Distribution Systems.  

National Technical Information Service (NTIS)

The purpose of this research is to develop a grid connected DC distribution system to ensure efficient integration of different alternate sources to the power system. An investigation of different AC and DC converter topologies and their control is conduc...

M. A. Elshaer

2012-01-01

37

Low cost soft switching DC-DC converter with autotransformer for photovoltaic hydrogen systems  

Microsoft Academic Search

In optimized photovoltaic-supplied hydrogen production systems, quite different levels of DC-voltages have to be linked via DC-DC power converters. For coupling of photovoltaics and electrolysis, a new step down DC-DC power converter has been developed, which uses an IGBT and an autotransformer together with a high frequency, zero-voltage switching concept to reduce losses. The concept allows conventional PWM control, high

Guntram Scheible; Heiko Solmecke; Detlev Hackstein

1997-01-01

38

Dc-ac three-phase four-wire Z-source converter with hybrid PWM strategy  

Microsoft Academic Search

This paper presents a hybrid PWM strategy for dc-ac three-phase four-wire Z-source converters. The technique combines the theory of space-vector PWM with the ease of implementation of a triangular-comparison PWM. Such strategy reduces the effort of algorithm calculation. The introduction of the distribution ratio in this technique, allows the development of a systematic approach for implementation of either conventional or

E. C. dos Santos; J. H. G. Muniz; E. P. X. P. Filho; E. R. C. da Silva

2010-01-01

39

Analysis of current density and electric field beneath a bipolar DC wires-to-plane corona discharge in humid air  

NASA Astrophysics Data System (ADS)

This paper aims to analyze the behavior of DC bipolar corona discharge in a two wires-to-plane configuration under variable humid air conditions. A circular biased probe was adapted to the plane and used to measure the ground-plane current density and electric field during the bipolar corona. The values of the electric field and the current density at the plane surface were the maximum beneath the two corona wires which decreased when moving away from them. The current-voltage characteristics followed the quadratic Townsend's law. The experimental results show that the bipolar corona discharge is strongly affected by the air humidity. The current density and the electric field decrease linearly with the humidity for all the tested wire diameters.

Aissou, Massinissa; Aitsaid, Hakim; Nouri, Hamou; Zebboudj, Youcef

2013-03-01

40

The dream and reality of automated wiring systems  

SciTech Connect

This article examines the use of computer programs for automated substation/switchgear wiring in order to cut production costs associated with wiring diagrams and documentation. The topics of the article include automating the process, schematic capture editor, wiring diagram editor, design aids and documentation, display formats, and system benefits.

Manno, R.; Dugan, D.

1994-01-01

41

The biomechanics of wire fixation in the Ilizarov system  

Microsoft Academic Search

The purpose of this study was to establish the optimal fixation of tensioned wires to the frame construct in the Ilizarov system. The usual torque to which the fixation bolts were tightened in clinical practice was established by serial testing of orthopaedic surgeons’ work in our unit.The force required to produce wire slippage from the different types of wire fixation

M. M. Mullins; A. W. Davidson; David Goodier; M. Barry

2003-01-01

42

A new DC-DC converter for fuel cell powered distributed residential power generation systems  

Microsoft Academic Search

Fuel cell powered distributed residential power generation systems are considered attractive because of their various advantages, such as high efficiency, low pollution, and low noise. A DC-DC converter having a high turn ratio transformer is needed in such a system, to boost the low voltage of the fuel cell to a high level, to enable the DC-AC conversion and to

Rahul Sharma; Hongwei Gao

2006-01-01

43

A priori wiring estimations and optimal multilevel wiring networks for portable ULSI systems  

Microsoft Academic Search

Based on Rent's rule, a well established empirical relationship, a rigorous derivation of a complete wire length distribution for on-chip random logic networks is performed and then used to describe an optimal architecture for a multilevel wiring network that provides maximum interconnect density and minimum power for a portable ULSI system

Jeffiey A. Davis; V. K. De; J. D. Meindl

1996-01-01

44

Optimal control of a dc transmission system  

Microsoft Academic Search

A new control scheme based on optimal control theory is proposed for dc power systems. Systematic methods are presented for computing the optimal and suboptimal feedback controllers. Specific suboptimal controllers are considered in detail and compared with the optimal control, and it is shown that use of local feedback measurements is possible with negligible loss of dynamic performance. A detailed

F. Nozari; D. P. Carrol

1975-01-01

45

Technology update II: Wire systems diagnostics & prognostics  

Microsoft Academic Search

The Aviation industry is gradually realizing some of the benefits from wire husbandry as they include it in their maintenance programs. Individual operators are also beginning to incorporate both zonal visual inspection procedures and advanced diagnostic tooling practices into their maintenance programs. Visual inspection, although only 25% effective is being used to check for wire contamination, combustibles and wire degradation

Christopher Teal; Bill Larsen

2003-01-01

46

A Microgrid-based Telecom Power System using Modular Multiple-Input DC-DC Converters  

Microsoft Academic Search

This paper presents a telecom power plant that uses local distributed generation resources and the utility grid as power inputs to the system. The microsources are connected to a high voltage main dc bus using multiple-input dc-dc converters. Additional converters are used in the secondary power distribution frames. The proposed architecture reduces the energy storage requirements and is more reliable

Alexis Kwasinski; P. T. Krein

2005-01-01

47

DC microgrid based distribution power generation system  

Microsoft Academic Search

This paper describes an autonomous-control method for a DC microgrid system having distribution power generators. This system consists of following five generation and control units; a solar-cell generation unit, a wind-turbine generation unit, a battery energy-storage unit, a flywheel power-leveling unit, and an AC grid-connected power control unit. The proposed control method intended for suppression of circulating current detects only

Y. Ito; Y. Zhongqing; H. Akagi

2004-01-01

48

DC bus voltage control for a distributed power system  

Microsoft Academic Search

This paper addresses voltage control of distributed DC power systems. DC power systems have been discussed as a result of the introduction of renewable, small-scale power generation units. Also, telecommunication power systems featuring UPS properties might benefit from a broader introduction of DC power systems. Droop control is utilized to distribute the load between the source converters. In order to

P. Karlsson; J. Svensson

2003-01-01

49

Low Current AC Partial Discharge Diagnostic System for Wiring Diagnostics.  

National Technical Information Service (NTIS)

A system and method for detecting partial discharges or arcing in wiring or cables is disclosed. The system employs a high-voltage AC power source to generate a high-voltage, low-current AC waveform, which is propagated through a selected wire, which in t...

J. G. Sarkozi

2004-01-01

50

A new flying wire system for the Tevatron  

Microsoft Academic Search

A new flying wire system replaces an older system to enhance the analysis of beam emittance, improve reliability, and support future upgrades to the Tevatron. New VME data acquisition and timing modules allow for more bunches to be sampled more precisely. A LabVIEW application, running on a Macintosh computer, controls the data acquisition and wire motion. The application also analyzes

Willem Blokland; G. Vogel; J. Dey

1997-01-01

51

A NEW FLYING WIRE SYSTEM FOR THE TEVATRON  

Microsoft Academic Search

A new flying wire system replaces an older system to enhance the analysis of beam emittance, improve reliability, and support future upgrades to the Tevatron. New VME data acquisition and timing modules allow for more bunches to be sampled more precisely. A LabVIEW application, running on a Macintosh computer, controls the data acquisition and wire motion. The application also analyzes

W. Blokland; G. Vogel; J. Dey; IL Batavia

1998-01-01

52

Arc Flash Calculations for Exposures to DC Systems  

Microsoft Academic Search

Electrical systems with AC voltage have been shown to exhibit arc flash incident energy during faults. Are there arc flash hazards related to dc systems, such as battery banks for UPS or drives, or dc buses used in chemical processes? Methods are available to estimate arc flash energy of ac exposures, but not dc. This paper will show the basic

Daniel R. Doan

2010-01-01

53

A distributed DC power system in an isolated island  

Microsoft Academic Search

This paper deals with a DC-micro grid in an isolated island. The proposed method is composed of gearless wind power generation system, battery, and DC loads in DC distribution system. The battery can avoid DC over-voltages by absorbing the PMSG power during line-fault. In addition, the control schemes in this paper include the maximum power point tracking (MPPT) control and

Kyohei Kurohane; Tomonobu Senjyu; Yuri Yonaha; Atsushi Yona; Toshihisa Funabashi; Chul-Hwan Kim

2009-01-01

54

New Solar Cell Power Supply System Using a Boost Type Bidirectinal DC-DC Converter  

Microsoft Academic Search

A new solar cell power supply system is presented, in which the boost type bidirectional dc-dc converter and the simple control circuit with a small monitor solar cell are employed to track the maximum power point of the solar array. It is confirmed by the experiment that the new system has sufficiently precise tracking operation performance and satisfactorily high power

Hirofumi Matsuo; Fujio Kurokawa

1984-01-01

55

Modeling of DC-DC converter for solar energy system applications  

Microsoft Academic Search

This paper presents the design and simulation of a DC-DC boost converter which uses solar system as input source. In general, solar is one of renewable energy sources which is sustainable and free if compared to other alternative energy. The voltage of solar system can produce a maximum voltage up to 16V during daylight and it is compatible enough with

M. Z. Ab Muin

2012-01-01

56

Plasmon hybridization in parallel nano-wire systems  

SciTech Connect

We apply the plasmon hybridization method to a double-nano-wire system, providing a simple and intuitive description of the plasmon excitations in the system. We apply the two-center cylindrical coordinate system for mathematical convenience and find an explicit form of the surface plasmon oscillations, in terms of the interaction between the bare plasmon modes of the individual surfaces of the nano-wires. We present numerical results to display how the plasmon excitations of the system depend on nano-wire separation when there is no angular momentum transfer, i.e., when m = 0.

Moradi, Afshin [Department of Nano Science, Kermanshah University of Technology, Kermanshah 67178-63766 (Iran, Islamic Republic of) and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran 19395-5531 (Iran, Islamic Republic of)

2011-06-15

57

Beam Position and Phase Monitor - Wire Mapping System  

SciTech Connect

The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

Watkins, Heath A [Los Alamos National Laboratory; Shurter, Robert B. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory

2012-04-10

58

Novel solar cell power supply system using the multiple-input DC-DC converter  

Microsoft Academic Search

Recently, clean electric power generation systems have attracted a great deal of social attention to exploit clean energy resources such as solar arrays, wind generators, fuel cells, etc. In this case, the multiple-input DC-DC power converter is useful to combine the several input power sources and to supply the regulated output voltage for the load. The novel solar cell power

Hirohmi Matsuo; Kimiyoshi Kobayashi; Yutaka Sekine; Matsuyoshi Asano; Lin Wenzhong

1998-01-01

59

System energy minimization via joint optimization of the DC-DC converter and the core  

Microsoft Academic Search

This paper addresses the problem of designing energy- efficient embedded systems by jointly optimizing the power consumption of both the DC-DC converter and the computational core. Past work has shown that there exists a minimum energy operating point (MEOP) in the subthreshold region for computational cores (C-MEOP), at which the dynamic and leakage powers are balanced. The MEOP is defined

Rami A. Abdallah; Pradeep S. Shenoy; Naresh R. Shanbhag; Philip T. Krein

2011-01-01

60

Flow characteristics of dc wire-non-parallel plate electrohydrodynamic gas pumps  

Microsoft Academic Search

An experimental investigation has been conducted to study the effect of grounded electrode location and polarity on time averaged discharge current, velocity profile, volumetric flow rate and pressure generation for a wire-non-parallel plate type EHD gas pump. The experiments were conducted with two different electrode configurations for the negative and positive applied voltages from 0 to 14kV at atmospheric pressure

H. Tsubone; J. Ueno; B. Komeili; S. Minami; G. D. Harvel; K. Urashima; C. Y. Ching; J. S. Chang

2008-01-01

61

Wire rope research and logging. [Skyline and dragline systems  

SciTech Connect

The various factors affecting the service life of wire ropes in skyline and dragline systems are discussed: design, geometry, sheave geometry, wear and lubrication, sheave hardness, pickup of small rocks, etc. (DLC)

Morgenstern, M.H.

1981-01-01

62

Direct DC-DC electric vehicle charging with a grid connected photovoltaic system  

Microsoft Academic Search

The Electric Vehicle\\/Photovoltaic Demonstration and Evaluation Program being conducted at the University of South Florida (USF) includes a 20 kW (peak) photovoltaic (PV) system in which PV panels form the roof of a 12 bay carport. A 6 kW (peak) segment of the PV system can be simultaneously distributed between computer controlled direct DC-DC charging and power grid interconnection. The

M. Vaidya; E. K. Stefanakos; B. Krakow; H. C. Lamb; T. Arbogast; T. Smith

1996-01-01

63

System identification of PWM dc-dc converters during abrupt load changes  

Microsoft Academic Search

System identification has an important role in control system design, particularly in auto-tuning and adaptive control applications. Recently, it has emerged as a significant research topic in power converter design. For this reason, this paper proposes a new on-line approach to identify the parameters of a dc-dc converter. The proposed method is capable of rapidly detecting and accounting for abrupt

Maher Algreer; Matthew Armstrong; Damian Giaouris

2009-01-01

64

Ferrite insertion at Recycler Flying Wire System  

SciTech Connect

Ferrite rods are installed inside the flying-wire cavity of the Recycler Ring and at entrance and exit beam pipes in order to absorb high-frequency electromagnetic waves excited by the beam. However, these rods may also deteriorate the vacuum pressure of the ring. An investigation is made to analyze the necessity of the ferrite rods at the entrance and exit beam pipes.

K.Y. Ng

2004-02-27

65

High-Speed Plated-Wire Memory System  

Microsoft Academic Search

The plated-wire memory, combined with functional circuit integration, is a strong contender for economic, high-speed, large-capacity memory systems. Important attributes of the plated-wire memory are high-speed DRO and NDRO capability, low digit WRITE current, high output sense signal and low word-to-digit line crosspoint capacitance. Design and operational results for a 1024-word by 80-bit store model are reported in detail. Utilizing

Sigurd Waaben

1967-01-01

66

SNS LINAC Wire Scanner System : Signal Levels and Accuracy.  

SciTech Connect

The linac wire scanner system for the Spallation Neutron Source (SNS) at Oak Ridge, TN, USA, calls for 5 units in the medium energy beam transport (MEBT), 5 in the drift tube linac (DTL), and 10 in the coupled cavity linac (CCL). In this paper we present expected signal levels and an analysis of the error in the beam size measurement as functions of wire position and electrical signal errors.

Plum, M. A. (Michael A.); Christensen, W. (Wynn); Myer, R. E. (Ross E.); Rose, C. R. (Chris R.)

2002-01-01

67

One-Wire Smart Motors Communicating over the DC Power Bus-Line with Application to Endless Rotary Joints  

Microsoft Academic Search

A system of multi-axis networked smart motors is developed to reduce complex cable harnesses. Motor control signals are sent over the DC power bus line and received by motors with integrated power amplifiers and controllers. The noise level and signal attenuation are low, allowing for high fidelity, broadband communication among many smart motors without bulky, costly cables. A modem is

Eric Wade; H. Harry Asada

2002-01-01

68

Design and control of Series DC Active Filter (SDAF) for shipboard Medium-Voltage DC power system  

Microsoft Academic Search

Shipboard power system (SPS) can have either ac or dc distribution systems, or a c ombination of both ac and dc distribution systems. However, the Navy has identified Medium- Voltage DC (MVDC) as a long-term solution for electric power distribution to meet the high pow er density requirements in future shipboard power systems. Thyristor bridges are a v iable front-end

Hesam Mirzaee; Babak Parkhideh; Subhashish Bhattacharya

2011-01-01

69

A Laser-Wire System at the ATF Extraction Line  

SciTech Connect

A new laser-wire (LW) system has been installed at the ATF extraction line at KEK, Tsukuba. The system aims at a micron-scale laser spot size and employs a mode-locked laser system. The purpose-built interaction chamber, light delivery optics, and lens systems are described, and the first results are presented.

Boogert, S.T.; Blair, G.; Boorman, G.; Bosco, A.; Deacon, L.; Driouichi, C.; Karataev, P.; /Royal Holloway, U. of London; Kamps, T.; /BESSY, Berlin; Delerue, N.; Dixit, S.; Foster, B.; Gannaway, F.; Howell, D.F.; Qureshi, M.; Reichold, A.; Senanayake, R.; /Oxford U.; Aryshev, A.; Hayano, H.; Kubo, K.; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba /Liverpool U. /Cockcroft Inst. Accel. Sci. Tech. /SLAC

2007-02-12

70

Capacity improvements for rural single wire earth return systems  

Microsoft Academic Search

The single wire earth return, (SWER), system is a low cost power distribution method that finds international use in rural areas, it is a key technology for the extension of grid systems. In Australia, SWER systems can cover vast areas. A single SWER system may typically supply 100 kW to several dozen customers and may extend more than 300 km.

P. J. Wolfs

2005-01-01

71

Reactor based Voltage Regulators for Single Wire Earth Return Systems  

Microsoft Academic Search

Single wire earth return systems, (SWER), are the lowest cost technology for rural power distribution and have global application. Voltage regulation is the determining factor for system capacity for long SWER systems. In long systems, directly connected shunt reactors are often used to compensate the effects of line to ground capacitance. The replacement of fixed shunt reactors with controllable reactors

Peter Wolfs; Steven Senini; Anthony Loveday; Jon Turner; Rockhampton Australia

72

Humanoid robot system design based on DC reduction servo motor  

Microsoft Academic Search

The paper presents a humanoid robot system based on DC reduction servo motor, this system consists of mechanical part and control part. The mechanical part has 21 degrees of freedom (DOF) and the control part uses SH14-M DC reduction servo motor to drive each joint. The upper computer software and the lower STC controller make the edit, debug and copy

Honghong Guo; Zhiyong Mao; Jiancheng Zhang

2011-01-01

73

Novel Solar-Cell Power Supply System Using a Multiple-Input DC–DC Converter  

Microsoft Academic Search

Recently, the clean electric power generation systems have attracted a great deal of social attention to exploit the clean-energy resources such as solar arrays, wind generators, fuel cells, and so forth. In this case, a multiple-input dc–dc converter is useful to combine the several input power sources and to supply the regulated output voltage for the load from the power

Kimiyoshi Kobayashi; Hirofumi Matsuo; Yutaka Sekine

2006-01-01

74

Interconnecting DC-Energy Systems: Responses to Technical Issues.  

National Technical Information Service (NTIS)

Photovoltaic systems and other dc-power systems will play a role in the future by providing power in many utility systems. Realization of projected economic benefits, however, depends on resolution of technical interconnection issues such as protection, p...

D. Curtice J. B. Patton

1983-01-01

75

Newly improved polymer alloy systems for printed wiring boards  

Microsoft Academic Search

A novel laminating resin system using polymer alloy technologies was investigated to see if it could meet demands of high density printed wiring boards. An experimental study was carried out on thermoplastic and thermosetting polymer alloy systems. Two combinations of linear phenoxy resin and thermosetting epoxy resin were characterized to investigate the synergetic qualities of the resin systems. For one

S. Oka; T. Takahama; H. Nakajima

1989-01-01

76

Damping phenomena in a wire rope vibration isolation system  

NASA Astrophysics Data System (ADS)

A study is presented of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators, with emphasis placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase plane trajectories, and frequency response curves are obtained. A semiempirical model having nonlinear stiffness, nth-power velocity damping, and variable Coulomb friction damping is developed, and the results are compared to experimental data. Several observations and conclusions are made about the dynamic phenomena in a typical wire rope vibration isolation system based on the experimental and semiempirical results.

Tinker, M. L.; Cutchins, M. A.

1992-08-01

77

Damping phenomena in a wire rope vibration isolation system  

NASA Astrophysics Data System (ADS)

A study of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators is presented. Emphasis is placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase trajectories, and frequency response curves were obtained. A semi-empirical model having nonlinear stiffness, nth-power velocity damping, and variable Coulomb friction damping is developed and results are compared to experimental data. Conclusions about dynamic phenomena in the wire rope system are made based on the experimental and semi-empirical results.

Tinker, Michael L.; Cutchins, Malcolm A.

78

Effect of impurities on the steady component of the current in a quantum wire under the joint action of ac and dc fields  

SciTech Connect

The current flowing along a cylindrical quantum wire with a superlattice in the case of the simultaneous application of dc and ac fields is calculated. It is assumed that the wire contains impurity centers, whose ionization results in the generation of nonequilibrium carriers in the conduction band. It is found that the dependence of the steady component of the current on the ac-field frequency is a step-like function. It is shown that the distance between steps depends on the conduction miniband width and the transverse quantum confinement parameters and is independent of the impurity-level depth.

Zav'yalov, D. V., E-mail: sed@fizmat.vspu.ru; Kryuchkov, S. V. [Volgograd State Pedagogical University (Russian Federation)

2008-10-15

79

Wired.  

ERIC Educational Resources Information Center

|Discusses technology's impact on scoreboard design: the development of the light-emitting diode (LED) display. How the LED system works is explained, as are the advantages and disadvantages of LED compared with incandescent lamp boards. Final comments address deciding on materials for scoreboard casings. (GR)|

Conklin, Aaron R.

1998-01-01

80

Multichannel dc SQUID system with two stage configuration  

NASA Astrophysics Data System (ADS)

For experimental evaluation, two channel dc SQUID system of the parallel type has been constructed. We have confirmed the following performances; voltage bias operation can accept any dc SQUID with different critical current, crosstalk between channels is negligibly small, and noise reduction can achieve owing to the flux gain. This work is partly supported by SUZUKI MEDICAL SCIENCE RESEARCH FOUNDATION.

Furukawa, H.; Fujita, S.; Matani, A.; Yoshida, M.; Shirae, K.

1990-08-01

81

CSMP (Continuous System Modeling Program) modeling of brushless DC motors  

Microsoft Academic Search

Recent improvements in rare earth magnets have made it possible to construct strong, lightweight, high horsepower DC motors. This has occasioned a reassessment of electromechanical actuators as alternatives to comparable pneumatic and hydraulic systems for use in flight control actuators for tactical missiles. This thesis develops a low-order mathematical model for the simulation and analysis of brushless DC motor performance.

S. M. Thomas

1984-01-01

82

Voltage and Frequency Controller for a Three-Phase Four-Wire Autonomous Wind Energy Conversion System  

Microsoft Academic Search

This paper deals with control of voltage and frequency of an autonomous wind energy conversion system (AWECS) based on capacitor-excited asynchronous generator and feeding three-phase four-wire loads. The proposed controller consists of three single-phase insulated gate bipolar junction transistor (IGBT)-based voltage source converters (VSCs) and a battery at dc link. These three single-phase VSCs are connected to each phase of

Bhim Singh; Gaurav Kumar Kasal

2008-01-01

83

Damping phenomena in a wire rope vibration isolation system  

Microsoft Academic Search

A study is presented of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators, with emphasis placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase plane trajectories, and frequency response curves are obtained. A semiempirical model having nonlinear stiffness,

M. L. Tinker; M. A. Cutchins

1992-01-01

84

Damping phenomena in a wire rope vibration isolation system  

Microsoft Academic Search

A study of the dynamic characteristics of a wire rope vibration isolation system constructed with helical isolators is presented. Emphasis is placed on the analytical modeling of damping mechanisms in the system. An experimental investigation is described in which the static stiffness curve, hysteresis curves, phase trajectories, and frequency response curves were obtained. A semi-empirical model having nonlinear stiffness, nth-power

Michael L. Tinker; Malcolm A. Cutchins

1990-01-01

85

SNMP-based Integrated Wire\\/wireless Device Management System  

Microsoft Academic Search

Wireless devices become familiar. We regard digital utilities' development as a middle of way to ubiquitous computing environment. This change of network access environment at the end user brings more possibility to hack wireless devices. Lost of a device brings side-effects of private information problems. Thus, we propose an integrated wire\\/wireless device management system. The proposed system monitors devices, manages

Soo-Jin Jung; Jong-Hyouk Lee; Young-Ju Han; Jong-Hyun Kim; Jung-Chan Na; Tai-Myoung Chung

2007-01-01

86

Parallel Fly-by-Wire Helicopter Control System.  

National Technical Information Service (NTIS)

This report describes a technology program for a candidate Fly-by-Wire (FBW) Control System with an auxiliary (back-up) mechanical control system for use in a potential test helicopter. In addition to covering the basic program, it includes an updated dis...

M. R. Murphy D. E. Haskins

1982-01-01

87

THREE-PHASE COMPENSATOR FOR LOAD BALANCING AND REACTIVE POWER COMPENSATION IN THREE-PHASE, FOUR-WIRE ELECTRIC POWER DISTRIBUTION SYSTEMS  

Microsoft Academic Search

This paper deals with a three-phase active power compensator (APC) to compensate reactive power and to balance unbalanced loads in the three-phase four-wire electric power distribution system. An APC is realized employing three single phase IGBT based VSI bridges with a common dc bus capacitor. Reference supply currents are estimated using P-I control over the average dc bus voltage and

BHIM SINGH; K. AL-HADDAD; A. CHANDRA; D. P. KOTHARI

1998-01-01

88

Design on Triple Bidirectional DC\\/DC Converter Used for Power Flow Control of Energy Storage in Wind Power System  

Microsoft Academic Search

\\u000a A triple bi-directional DC\\/DC converter used for power flow control of energy storage in wind power system is designed. Firstly,\\u000a the paper analyzes energy flow characteristic of wind power system containing hybrid energy storage (the battery and the supercapacitor).\\u000a Secondly, working principle of the triple bi-directional DC\\/DC converter is explained and mathematical model is constructed.\\u000a Then, based on the model,

Yanlei Zhao; Naiyong Xia; Housheng Zhang

89

A Bi-Directional Isolated DC/DC Converter as a Core Circuit for 3.3-kV/6.6-kV Power Conversion Systems in the Next Generation  

NASA Astrophysics Data System (ADS)

This paper describes a bi-directional isolated dc/dc converter considered as a core circuit of 3.3-kV/6.6-kV high-power-density power conversion systems in the next generation. The dc/dc converter is intended to use power switching devices based on SiC and/or GaN, which will be available on the market in the near future. A 350-V, 10-kW and 20kHz dc/dc converter is designed, constructed and tested in this paper. It consists of two single-phase full-bridge converters with the latest trench-gate Si-IGBTs and a 20-kHz transformer with a nano-crystalline soft-magnetic material core and litz wires. The transformer plays an essential role in achieving galvanic isolation between the two full-bridge converters. The overall efficiency from the dc-input to dc-output terminals is accurately measured to be as high as 97%, excluding gate drive circuit and control circuit losses from the whole loss. Moreover, loss analysis is carried out to estimate effectiveness in using SiC-based power switching devices. The loss analysis clarifies that the use of SiC-based power devices may bring a significant reduction in conducting and switching losses to the dc/dc converter. As a result, the overall efficiency may reach 99% or higher.

Inoue, Shigenori; Akagi, Hirofumi

90

Temperature Analysis of Copper Wire in a Plasma Annealing System at Atmospheric Pressure  

Microsoft Academic Search

In this study, the temperature characteristic of the thin copper wire annealed in atmospheric pressure dielectric barrier discharge (APDBD) system is studied. An equivalent circuit model was used to analyze the wire surface temperature in APDBD. The analysis model showed that the ion bombardment on the wire surface was the main factor that determined wire surface temperature. The average temperature

Dam N. Tran; Vinh P. Nguyen; Toru Sasaki; Takashi Kikuchi; Nobuhiro Harada

2011-01-01

91

14 CFR 26.11 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2013 CFR

...and Space 1 2013-01-01 2013-01-01 false Electrical wiring interconnection systems (EWIS) maintenance program...Enhanced Airworthiness Program for Airplane Systems § 26.11 Electrical wiring interconnection systems (EWIS) maintenance...

2013-01-01

92

Steering control of motorcycles using steer-by-wire system  

Microsoft Academic Search

This study proposes a steering control method to improve motorcycle handling and stability. Steer-by-wire (SBW) technology is applied to the motorcycle's steering system to remove characteristic difficulties of vehicle maneuvers. By examining computer simulation using a simplified motorcycle model, the actual rolling angle of the SBW motorcycle is controlled to follow the desired rolling angle intended by the rider. A

Y. Marumo; M. Nagai

2007-01-01

93

Control of Flow past a Stationary Circular Cylinder: Effects of a Single Straight Wire and a System of Helical Wires  

NASA Astrophysics Data System (ADS)

Effects of geometric disturbances on the surface of a circular cylinder are investigated experimentally via Particle Image Velocimetry (PIV). Consideration is given to a single straight wire and a system of three equidistant helical wires. The Reynolds number is 10,000 and the scale of the wire is about one percent of the cylinder diameter; moreover, the wire diameter is smaller than the thickness of the unperturbed boundary layer developing around the cylinder. A straight wire, located at an angle of 60^o from the forward stagnation point of the cylinder, yields bistable shear layer oscillations between two distinct states involving reattachment and no reattachment downstream of separation at the wire. For the helical wire system, bistable oscillations also occur at the flow cross-section where the helical wire passes through this same critical angular location on the cylinder surface. These types of small-scale geometric disturbances do not attenuate the Karman instability in the presence of bistable oscillations. However, they markedly influence the onset of instability of the separated shear layer.

Ekmekci, Alis; Rockwell, Donald

2009-11-01

94

EMTP System Level Model of the PMAD DC Test Bed.  

National Technical Information Service (NTIS)

A power management and distribution direct current (PMAD DC) test bed was set up at the NASA Lewis Research Center to investigate Space Station Freedom Electric Power Systems issues. Efficiency of test bed operation significantly improves with a computer ...

N. V. Dravid T. J. Kacpura K. Tam

1991-01-01

95

Mission profile optimized modularization of hybrid vehicle DC\\/DC converter systems  

Microsoft Academic Search

Vehicles based on electrical drive trains become more and more attractive due to rising oil prizes and environmental reasons. In these vehicles usually different and\\/or varying voltage levels for the drive and the energy storage elements are employed in order to fully utilise the components and increase the system efficiency. The DC- links with different voltage levels are interconnected by

J. Biela; S. Waffler; J. W. Kolar

2009-01-01

96

New DC–DC Converter for Energy Storage System Interfacing in Fuel Cell Hybrid Electric Vehicles  

Microsoft Academic Search

The use of energy storage devices such as batteries or supercapacitors is almost mandatory in fuel cell hybrid electric vehicles, in order to guarantee load leveling, assuring braking energy recovery and good performances in transient operations. To this end, converters with bidirectional power flows are needed to connect the accumulators to the dc-link of the motor drive system. In this

Mario Marchesoni; Camillo Vacca

2007-01-01

97

Integrated control of a stand-alone photovoltaic system based on decentralized DC-DC converters  

Microsoft Academic Search

This paper presents a scheme for supervisory control of decentralized stand-alone PV systems. The control is designed to maintain the DC bus regulated independently of solar irradiation, battery charge and load demands. In order to achieve this objective we propose an overall power management strategy to control power flows among PV arrays, battery bank, and inverter. Experimental results for a

Diogo B. Cândido; Leandro Michels; Hélio L. Hey

2010-01-01

98

AC load conditioner and DC bus conditioner for a DC distribution power system  

Microsoft Academic Search

A PEBB (power electronics building block) based power converter system is described to provide a secondary utility bus in a DC distributed power system on a ship. The power converter system consists of a main inverter and a multi-functional load conditioner to achieve low voltage distortion under unbalanced and\\/or nonlinear loads. A four-legged three-phase power converter topology is used for

R. Zhang; Fred C. Lee; Dushan Boroyevich; Changrong Liu; Lijia Chen

2000-01-01

99

dc: a live Webcast control system  

NASA Astrophysics Data System (ADS)

Live Internet streaming media programs, called webcasts, can adopt techniques developed by television to obtain higher quality. We have developed a general webcast production model composed of three stages (i.e., sources, broadcast, and transmission) and a tool, called the Director's Console (dc), to control live webcasts. The tool is one component of a distributed service architecture, which adapts to varying physical infrastructure and broadcast configurations.

Yu, Tai-Ping; Wu, David; Mayer-Patel, Ketan D.; Rowe, Lawrence A.

2000-12-01

100

Fundamental characteristics of DC microgrid for residential houses with cogeneration system in each house  

Microsoft Academic Search

DC microgrid is a novel power system using dc distribution in order to provide a super high quality power. This system is suitable for dc output type distributed generations and energy storages. The dc power can be converted to the proper ac or dc voltages for the consumers by converters placed near loads, and these converters do not require transformers.

H. Kakigano; Y. Miura; T. Ise; T. Momose; H. Hayakawa

2008-01-01

101

14 CFR 129.111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2013 CFR

...and Space 3 2013-01-01 2013-01-01 false Electrical wiring interconnection systems (EWIS) maintenance program...Continued Airworthiness and Safety Improvements § 129.111 Electrical wiring interconnection systems (EWIS) maintenance...

2013-01-01

102

Commissioning a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of the quadrupoles. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing such a system. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). A previous study investigated the error associated with each step by using a permanent quadrupole magnet on an optical mover system. The study reported an error of 11{micro}m for step 1 and a repeatability of 4{micro}m for step 2. However, the set up used a FARO arm to measure tooling balls and didn't allow to accurately check step 2 for errors; an uncertainty of 100{micro}m was reported. Therefore, even though the repeatability was good, there was no way to check that the error in step 2 was small. Following the recommendations of that study, we used a CMM (Coordinate Measuring Machine) instead of the FARO arm for measuring the tooling balls. In addition, a roller cam positioner system replaced the optical movers for moving the quadrupole. With the exception of the quadrupole itself, the system was identical to what will be used in fiducializing the undulator quadrupoles. In this study, we investigate the new vibrating wire set up, including the error associated with each step of fiducialization. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note is a continuation of previous work to study the ability of the system to fulfill the fiducialization requirements.

Levashov, Michael Y

2010-12-03

103

Protective Relaying Systems Using Pilot-Wire Channels  

Microsoft Academic Search

This paper has presented a variety of pilot-wire relaying systems. Each has its field of application which is influenced by technical and economic factors, as listed in the previous section. In many cases, particularly where tapped or multiterminal lines are concerned, combinations of the various systems will be necessary for high-speed simultaneous clearing of faults. Experience has indicated that well-designed

H. W. Lensner

1960-01-01

104

Recycling system for printed wiring boards with mounted parts  

Microsoft Academic Search

A practical recycling system has been developed for printed wiring boards (PWBs) with electronic parts mounted on them. This system consists of part-removing, solder-removing and resin-board pulverizing\\/separating processes, and is effective in the recovery of useful materials. The authors have developed a part-removal apparatus which successfully removes through-hole devices as well as surface mounted devices from PWBs with almost no

S. Yokoyama; Y. Ikuta; M. Iji

1999-01-01

105

A continent bound by wire [telegraph system  

Microsoft Academic Search

The development of the transcontinental telegraph system is recounted. The Pony Express helped to establish routes for the system, leading to its own demise. In 1860, Western Union received a government subsidy to build an uninterrupted telegraph line from east to west. The logistics of this venture are described. On the eve of the Civil War, telegraph lines stretched through

B. Finn

1990-01-01

106

Dc power supplies and hard-tube power conditioning systems  

SciTech Connect

In this lecture, we shall discuss some of the major characteristics of dc power supplies and hard-tube pulsers, along with many of their PCS limiting properties and several of the more powerful vacuum tubes that are currently available for larger hard-tube pulsers systems. The initial topic will be elementary dc power supplies, operating with standard 60 Hz AC input power. The full-wave bridge design will be discussed in detail, illustrating the majority of the significant circuit parameters.

Sarjeant, W.J.

1980-01-01

107

A purely ultracapacitor energy storage system hybrid electric vehicles utilizing a based DC-DC boost converter  

Microsoft Academic Search

The design and testing of a purely ultracapacitor energy storage system for the improvement of hybrid electric vehicles is presented. The system utilizes two large ultracapacitor banks for energy storage and a dc-dc boost converter that is capable of supplying 8 kW for voltage regulation. The system provides greater roundtrip efficiency over batteries, improves a vehicle's ability to recapture energy

Erik J. Cegnar; Herb L. Hess; Brian K. Johnson

2004-01-01

108

Development of a DC Current Limiting Interrupting System for Mines.  

National Technical Information Service (NTIS)

A switching system for high fault current, 300- and 600-volt dc trolley and haulage systems, as used in the mining industry are presented. The system consists of paralleled main and auxiliary contactor circuits with a liquid metal current limiting device ...

H. B. Hamilton

1982-01-01

109

A pseudodifferential amplifier for bioelectric events with DC-offset compensation using two-wired amplifying electrodes  

Microsoft Academic Search

Most wired active electrodes reported so far have a gain of one and require at least three wires. This leads to stiff cables, large connectors and additional noise for the amplifier. The theoretical advantages of amplifying the signal on the electrodes right from the source has often been described, however, rarely implemented. This is because a difference in the gain

Thomas Degen; Heinz Jäckel

2006-01-01

110

Angular Dependence of Transport AC Losses in Superconducting Wire with Position-Dependent Critical Current Density in a DC Magnetic Field  

NASA Astrophysics Data System (ADS)

Transport AC losses play a very important role in high temperature superconductors (HTSs), which usually carry AC transport current under applied magnetic field in typical application-like conditions. In this paper, we propose the analytical formula for transport AC losses in HTS wire by considering critical current density of both inhomogeneous and anisotropic field dependent. The angular dependence of critical current density is described by effective mass theory, and the HTS wire has inhomogeneous distribution cross-section of critical current density. We calculate the angular dependence of normalized AC losses under different DC applied magnetic fields. The numerical results of this formula agree well with the experiment data and are better than the results of Norris formula. This analytical formula can explain the deviation of experimental transport current losses from the Norris formula and apply to calculate transport AC losses in realistic practical condition.

Su, Xing-liang; Xiong, Li-ting; Gao, Yuan-wen; Zhou, You-he

2013-07-01

111

Vacuum system of heavy ion cyclotron complex DC-60  

NASA Astrophysics Data System (ADS)

The vacuum system of the heavy ion cyclotron complex DC-60 created at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research for the interdisciplinary research complex (Astana, Kazakhstan) is described. The results of numerical simulation of transmission efficiency of accelerated ions in the course of recharging on residual gas, which determines the basic parameters of the designed vacuum system, are presented. As a result of successful implementation of the cyclotron complex DC-60 project, heavy ion beams were accelerated. The obtained parameters of the vacuum system agree completely with calculations, which were the basis of the project.

Gikal, B. N.; Tikhomirov, A. V.; Khabarov, M. V.; Chernyshev, O. A.

2008-07-01

112

DC-XA structural health-monitoring system  

NASA Astrophysics Data System (ADS)

The NASA/McDonnell Douglas Delta Clipper-Experimental Advanced (DC-XA) re-usable rocket program included the development of a Structural Health Monitoring System (SHMS) to acquire and present structural health information to the DC-XA flight team in near-real-time. The SHMS was successfully demonstrated in 1996 during flight tests of the DC-XA at White Sands Missile Range where it was used to support rapid vehicle turnaround and to provide an improved understanding of the DC-XA's advanced structural components, including a composite liquid hydrogen tank, composite interbank, and aluminum-lithium liquid oxygen tank. Development of the DC-XA SHMS required the selection and integration of fiberoptic and conventional sensors, development of an advanced, multi-channel fiberoptic sensor demodulator, investigation of sensor installation methods, and the development of structural health data analysis and visualization algorithms. This paper describes the design, implementation, and operation of the DC-XA SHMS. Results and conclusions from ground and flight tests are presented.

Baumann, Erwin W.; Becker, Ronald S.; Ellerbrock, Phillip J.; Jacobs, Steven W.

1997-05-01

113

A Testing System for Diagnosing Misconceptions in DC Electric Circuits.  

ERIC Educational Resources Information Center

|Outlines a test-based diagnosis system for misconceptions in DC electric circuits and its three parts: problem library, problem selector and diagnoser. Discusses misconception discrimination and diagnosis theories, and reports the system supports satisfactory diagnosis. Includes an analysis of nine student misconceptions about electrical circuits…

Chang, Kuo-En; Liu, Sei-Hua; Chen, Sei-Wang

1998-01-01

114

Uprated dc power system and thermalhydraulic facilities at Columbia University  

Microsoft Academic Search

The necessity of carrying out large scale nuclear thermalhydraulic simulations is increasing. Such experiments call for large power sources, and to meet those requirements the dc power system at the Heat Transfer Research Facility of Columbia University has been upgraded to 11.5 MW. The uprated system, its installations, various subsystems, and operations are described. The thermalhydraulic loops and their auxiliary

W. E. Hovemeyer; S. R. Sreepada; J. E. Casterline

1978-01-01

115

Stray current control in DC mass transit systems  

Microsoft Academic Search

Stray current control is essential in direct current (DC) mass transit systems where the rail insulation is not of sufficient quality to prevent a corrosion risk to the rails, supporting and third-party infrastructure. This paper details the principles behind the need for stray current control and examines the relationship between the stray current collection system design and its efficiency. The

Ian Cotton; Charalambos Charalambous; Pete Aylott; Petra Ernst

2005-01-01

116

DC Voltage Control of the DC Micro-Grid for Super High Quality Electric Power Distribution  

NASA Astrophysics Data System (ADS)

DC Micro-grid” is a novel power system using dc distribution in order to provide super high quality electric power. The power is distributed through dc distribution line and converted to required ac or dc voltages by converters placed near loads. The load side converters do not need transformers by choosing proper distributed dc voltage (±170V). The dc distribution line is composed of 3 power lines: +170V line, neutral line and -170V line. The voltages of ±170V have to be balanced to supply high quality power. In this paper, a voltage balancing control method for dc distribution is proposed and studied. Computer simulation results demonstrated that dc micro-grid was able to supply both ac and dc power to loads simultaneously and stably by 3-wire dc distribution and load side converters.

Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi; Uchida, Ryohei

117

Battery model for overcurrent protection simulation of DC distribution systems  

Microsoft Academic Search

This paper describes an electrical model of a battery that can accurately simulate characteristic battery behaviour during overcurrent instances. The battery model can be coupled with other distribution component models to simulate the protection performance in telecommunication DC power distribution systems

Tim Robbins; John Hawkins

1994-01-01

118

Brushless DC Motor Propulsion Using Synchronous Motors for Transit Systems  

Microsoft Academic Search

In this paper, a brushless dc motor propulsion system using synchronous motors is described which is suitable for transit applications. The propulsion system consists of two-quadrant transistorized front-end chopper and a three-phase transistorized inverter (forming the electronic commutator for the synchronous machine phase currents) to provide both controlled propulsion and regenerative braking. The control scheme makes the system operate stably

W. R. PEARSONAND; Paresh C. Sen

1984-01-01

119

Harmonic elimination, reactive power compensation and load balancing in three-phase, four-wire electric distribution systems supplying non-linear loads  

Microsoft Academic Search

In this paper, a new control scheme of a three-phase active power filter (APF) is proposed to eliminate harmonics, to compensate reactive power and neutral currents and to remedy system unbalance, in a three-phase four-wire electric power distribution system, with unbalanced non-linear loads. The APF is realized using three single phase IGBT based PWM-VSI bridges with a common dc bus

Bhim Singh; Kamal Al-Haddad; Ambrish Chandra

1998-01-01

120

Novel calibration system with sparse wires for CMB polarization receivers  

SciTech Connect

B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

2011-07-01

121

A Purely Ultracapacitor Energy Storage System for Hybrid Electric Vehicles Utilizing a Microcontroller Based dc-dc Boost Converter  

Microsoft Academic Search

The design and testing of a purely ultracapacitor energy storage system for the improvement of hybrid electric vehicles is presented. The system utilizes two large ultracapacitor banks for energy storage and a dc-dc boost converter that is capable of supplying 8kW for voltage regulation. The system provides greater roundtrip efficiency over batteries, improves a vehicle's ability to recapture energy from

Erik J. Cegnar; Herb L. Hess; Brian K. Johnson

122

Human-simulated intelligent control of brushless DC motor system  

Microsoft Academic Search

A double-loop control system based on human-simulated intelligent control (HSIC) is designed using a mathematical model of a brushless DC motor (BLDCM). In the double-loop motor control system, a conventional PI controller is implemented for the current loop and an HSIC speed controller using the characteristic model-based multi-mode control is adopted for the speed loop. The controller parameters are set

Yang Hao; Li Zu-shu; Xue Fang-zheng; Luo Gang; Zhong Zao-sheng

2009-01-01

123

Electrostatic coalescence system with independent AC and DC hydrophilic electrodes  

DOEpatents

An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

Hovarongkura, A. David (Arlington, VA); Henry, Jr., Joseph D. (Morgantown, WV)

1981-01-01

124

Validation of digital simulation of DC links  

SciTech Connect

A project was undertaken to test the validity of the electromagnetic transients simulation of dc links using digital computer programs. The Nelson River dc transmission system of both Bipoles One and Two were modeled on the computer using Manitoba Hydro's EMTDC program. The well known Electromagnetic Transients Program EMTP was also used for small reduced system models. Results from actual system tests were used to compare with the computer simulation of the same test. Comparisons are also made between EMTDC and EMTP as simulation tools for studying dc transmission. Computer simulation of dc links is presented as a valid option to the use of real time hard wired simulators.

Woodford, D.A.

1985-09-01

125

Electromagnetic Energy Harvesting Circuit With Feedforward and Feedback DC–DC PWM Boost Converter for Vibration Power Generator System  

Microsoft Academic Search

This paper presents an integrated vibration power generator system. The system consists of a mini electromagnetic vibration power generator and a highly efficient energy harvesting circuit implemented on a minute printed circuit board and a 0.35-mum CMOS integrated chip. By introducing a feedback control into the dc-dc pulsewidth modulation (PWM) boost converter with feedforward control, the energy harvesting circuit can

Xinping Cao; Wen-Jen Chiang; Ya-Chin King; Yi-Kuen Lee

2007-01-01

126

Limit-Cycle Oscillations Based AutoTuning System for Digitally Controlled DC–DC Power Supplies  

Microsoft Academic Search

This paper introduces a new method and system for parameter extraction and automated controller adjustment, suitable for low power digitally controlled DC-DC switch-mode power supplies (SMPS). The system allows closed-loop calibration throughout regular converter operation. During a short-lasting test phase, SMPS parameters, such as output capacitance and load, are estimated by examining the amplitude and frequency of intentionally introduced limit

Zhenyu Zhao; Aleksandar Prodic ´

2007-01-01

127

Low-Ripple-Voltage and High-Speed Control System for Load Regulation of DC-DC Converter  

Microsoft Academic Search

This paper presents a new approach to creating high-performance control systems for DC-DC converters (switch- ing regulators) targeted for microprocessor and mobile equipment power supply applications. Power supply circuits demand both low-ripple-voltage in the steady state (stability) and fast response for large load changes. However, since in general stability and fast response are trade-off in control systems, it is difficult

Masashi Kono; Zhang Ting; Liu Aiyan; Keigo Kimura; Haruo Kobayashi; Yasunori Kobori

128

Selective polarization of nuclear spins in a wire-like quantum Hall system  

SciTech Connect

Nuclear spins are polarized selectively in a mesoscopic wire-like quantum Hall system by using the fractional quantum Hall system at Landau level filling factor nu = 2/3. The nuclear spin polarized region is limited by setting the filling factor in the wire to 2/3, while leaving the filling factor in the bulk away from 2/3. The longitudinal relaxation rate of selectively polarized nuclear spins probes electron spin properties in the wire.

Kobayashi, Takashi; Sasaki, Satoshi [NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa 243-0198 (Japan); Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Kumada, Norio; Ota, Takeshi [NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa 243-0198 (Japan); Hirayama, Yoshiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); ERATO-JST Nuclear Spin Electronics Project, 468-15 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-0845 (Japan)

2010-01-04

129

Feasibility analysis of the application and positioning of DC HTS FCL in a DC microgrid through modeling and simulation using Simulink and SimPowerSystem  

NASA Astrophysics Data System (ADS)

DC fault current limitation in DC distribution network is one of the critical issues which need to be taken care of before they can be practically implemented. High temperature superconductors could be efficiently installed to cope with the problem of DC fault currents. In this paper, a generalized DC high temperature superconducting fault current limiter (SFCL) is modeled by integrating Simulink and SimPowerSystem blocks. This model is designed for limiting DC fault currents in low voltage DC distribution networks.A DC microgrid having a low voltage DC distribution network, an integrated photovoltaic plant and domestic customer load is modeled. Transient analysis of the DC microgrid is performed by generating fault and measuring DC fault currents at critical points. The designed DC SFCL is placed at different strategic locations in DC microgrid and fault current limitation performance of DC SFCL in DC microgrid has been analyzed. Moreover, the affects of rapid impedance changing in the distribution network due to the fault followed by DC SFCL activation is investigated. Finally, the best suitable position and affects of DC SFCL in a DC microgrid along with suggestions for implementation have been proposed.

Khan, U. A.; Shin, W. J.; Seong, J. K.; Oh, S. H.; Lee, S. H.; Lee, B. W.

2011-11-01

130

Numerical analysis of the performance of wire mesh and cable net rockfall protection systems  

Microsoft Academic Search

Wire mesh and cable net systems have long been used to control rockfall on actively eroding slopes. The design of these systems has been primarily based on empirical methods, engineering judgment, and experience; their performance has been mixed. There is a general consensus among specialists that in wire mesh systems that have functioned well some elements may be over-designed or

N. Sasiharan; B. Muhunthan; T. C. Badger; S. Shu; D. M. Carradine

2006-01-01

131

Three-level half-bridge ZVS DC\\/DC converter for electrolyzer integration with renewable energy systems  

Microsoft Academic Search

This paper presents findings of a R&D project tar geted to the development of a galvanically isolated step-down DC\\/DC converter for electrolyzer integration with renewable energy systems. The topology proposed is a three-level neutral point clamped half-bridge with a high-frequency isolation transformer and a current doubler rectifier that fulfils all the targets set by the designers. Despite an increased component

Anna Andrijanovits; Dmitri Vinnikov; Indrek Roasto; Andrei Blinov

2011-01-01

132

DC grid management of a multi-terminal HVDC transmission system for large offshore wind farms  

Microsoft Academic Search

Multi-terminal HVDC transmission system technology using voltage source converters is proposed for integrating large offshore wind farms. Various DC grid management strategies based on coordinated close-loop DC voltage control and DC droop characteristics are proposed, to ensure smooth system operation and proper power sharing among various onshore AC networks. PSCAD\\/EMTDC simulations for a four-terminal DC system for connecting two offshore

Lie Xu; Liangzhong Yao; Masoud Bazargan

2009-01-01

133

An Approach to a Higher-Power-Density Power Supply for 380-V DC Distribution System  

NASA Astrophysics Data System (ADS)

A methodology for realizing a higher-power-density DC-DC converter has been proposed for a power unit installed in a 380-V DC distribution system. The possibility of the converter design will be strengthened by using the series-parallel connection topology for isolated DC-DC converters. A converter prototype with a power density of 10W/cm3 has been fabricated, and the feasibility of the converter design has been confirmed experimentally. This result contributes to the realization of a highly efficient and highly space-saving 380-V DC distribution system.

Hayashi, Yusuke; Mino, Masato

134

Fatigue analysis of the taut-wire mooring system applied for deep waters  

Microsoft Academic Search

Precisely predicting the fatigue life of taut-wire mooring systems has become an interesting and important problem for scientists and engineers since there are still difficulties in the inspection and maintenance of mooring lines in a rough sea environment especially in deep waters. In this paper, a comprehensive fatigue analysis is performed for a polyester taut-wire mooring system of an FPSO

Wei Huang; Hai-Xiao Liu; Gui-Min Shan; Cun Hu

2011-01-01

135

Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System  

ERIC Educational Resources Information Center

|We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

2012-01-01

136

Analysis of a Voltage-fed Full Bridge DC-DC Converter in Fuel Cell Systems  

Microsoft Academic Search

Fuel cells at moderate power levels have a high output current and low output voltage. In order to make them usable for applications with a higher voltage demand, a DC-DC converter with large voltage gain is needed. This paper deals with a voltage-fed full bridge converter that is designed to reach a high voltage gain. Analytical calculations are given, completely

A. Averberg; A. Mertens

2007-01-01

137

Large-Deflection Analysis of Automotive Vehicle's Door Wiring Harness System Using Finite Element Method  

Microsoft Academic Search

? Abstract—A Vehicle's door wireing harness arrangement structure is provided. In vehicle's door wiring harness(W\\/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness(W\\/H) in vehicle's door structures for durability problem. An Finite elements analysis

Byeong-Sam Kim; Kangsu Lee; Samir Ben Chaabane

2008-01-01

138

A new wire position monitor readout system for ILC cryomodules  

Microsoft Academic Search

Wire position monitors (WPMs) are used to measure the absolute position of superconductive RF cavities in prototype cryomodules developed for electron linacs such as FLASH and XFEL at DESY or the future ILC. The WPM consists of four metallic strips equally spaced in azimuth on a 12 mm diameter cylinder approximately coaxial with a reference wire excited with a 140

F. Bedeschi; G. Bellettini; A. Bosotti; R. Carosi; S. Galeotti; A. Gennai; C. Pagani; F. Paoletti; R. Paparella; D. Passuello; F. Spinella

2007-01-01

139

Power Sharing Control between Load-Side Inverters in DC Microgrid for Super High Quality Electric Power Distribution System  

Microsoft Academic Search

DC microgrid is a novel power system using dc distribution in order to provide a super high quality electric power. The dc distribution system is suitable for dc output type distributed generations such as photovoltaic and fuel cells, and energy storages such as batteries and electric double layer capacitors. Power is distributed through dc distribution line and converted to required

Hiroaki Kakigano; Kaho Nada; Yushi Miura; Toshifumi Ise; Ryohei Uchida

2008-01-01

140

Design and Implementation of a High-Power Resonant DC-DC Converter Module for a Reduced-Scale Prototype Integrated Power System.  

National Technical Information Service (NTIS)

An Integrated Power System (IPS) with a DC Zonal Electrical Distribution System (DC ZEDS) is a strong candidate for the next generation submarine and surface ship. To study the implementation of an IPS with DC ZEDS, members of the Energy Sources Analysis ...

B. D. Whitcomb

2001-01-01

141

A low-voltage CMOS DC-DC converter for a portable battery-operated system  

Microsoft Academic Search

Motivated by emerging battery-operated applications that demand compact, lightweight, and highly efficient DC-DC power converters, a buck circuit is presented in which all active devices are integrated on a single chip using a standard 1.2 ? CMOS process. The circuit delivers 750 mW at 1.5 V from a 6 V battery. To effectively eliminate switching loss at high operating frequencies,

Anthony J. Stratakos; Seth R. Sanders; Robert W. Brodersen

1994-01-01

142

ELECTROMAGNETIC WAVE PROPAGATION ALONG HORIZONTAL WIRE SYSTEMS IN OR NEAR A LAYERED EARTH  

Microsoft Academic Search

A review of the theory of electromagnetic wave propagation along a system of horizontal wires in a layered medium is given. Numerical results for the propagation constants of a variety of specific structures are presented and examined as functions of wire and medium parameters. The full modal description of such structures is discussed, and its relation to excitation by specific

Edward F. Kuester; David C. Chang; Steven W. Plate

1981-01-01

143

Active Microwave SingleWire Line System for Anisotropic Plasma Diagnostics  

Microsoft Academic Search

The interaction of the surface wave fields on a single-wire transmission line with an anisotropic plasma is treated. An equation relating the electron number density in the plasma to the frequency shift of a single-wire coupled active microwave system is derived. The equation shows that there is a linear relationship between the number density and frequency shift, and that the

R. E. Carawon; R. C. Ajmera

1981-01-01

144

High-density bidirectional rectifier for next generation 380-V DC distribution system  

Microsoft Academic Search

A high-density bidirectional rectifier was developed not only for telecom and data center applications but also for next generation 380-V DC distribution systems. A conventional rectifier consists of an AC 200-V\\/DC 380-V power factor correction (PFC) converter and an isolated DC 380-V\\/DC 380-V converter, and the power flow is unidirectional. Two approaches are proposed for creating a high-density bidirectional rectifier

Yusuke Hahashi; Masato Mino

2012-01-01

145

Control of Interaction Force of Twin Direct-Drive Motor System Using Variable Wire Rope Tension With Multisensor Integration  

Microsoft Academic Search

In this paper, a novel wire-based robot system with consideration of the different levels of wire rope tension is intro- duced, and its performance while executing a task in an unknown environment is analyzed. An adaptable wire rope tension control, called a twin direct-drive motor system, provides a unique struc- ture for a robot interaction system. Compared with conventional industrial

Chowarit Mitsantisuk; Kiyoshi Ohishi; Seiichiro Katsura

2012-01-01

146

Wire chamber requirements and tracking simulation studies for tracking systems at the superconducting super collider  

SciTech Connect

Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tracking systems which meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. Such computer simulation studies are necessary to determine the feasibility of wire chamber tracking systems for complex events in a high-rate environment such as the SSC. 11 refs., 9 figs., 1 tab.

Hanson, G.G.; Niczyporuk, B.B.; Palounek, A.P.T.

1989-02-01

147

A three-level DC-DC converter with wide-input voltage operations for ship-electric-power-distribution systems  

Microsoft Academic Search

This paper describes a newly developed three-level dc-dc converter with wide-input voltage operations for ship-electric-power-distribution systems. The proposed converter is designed with zero-voltage-switching (ZVS) techniques. The operational principles, design details and performances of the converter are discussed along with soft-switching characteristics through experimental results. Furthermore, design criteria on the dc-dc converter are focused on the minimization of the circulation current

Byeong-Mun Song; Robert McDowell; Andrew Bushnell; Joel Ennis

2004-01-01

148

Development and Analysis of a Wire-Based Robot With Twin Direct-Drive Motor System  

NASA Astrophysics Data System (ADS)

In this paper, a sensorless wire rope tension control is introduced and analyzed to implement a wire-based robot with twin direct-drive motor system. Two of the same direct-drive motors are required and connected by wire rope mechanism. In the controller design, dual disturbance observers with respect to two control modes, namely the common mode and the differential mode are designed and applied for control of motion and wire rope tension. The wire rope tension in the common mode is controlled in order to regulate the mechanical bandwidth of the system. From the identification results, the high-tension of wire rope system is obtained a high mechanical bandwidth in the robot systems. The disturbance observer-based eliminates the need for the tension sensors, and may also be used to achieve the precise velocity and position control with the vibration-free performance in the differential mode. The effectiveness of the proposed method is verified by experimental results. It is shown that the high frequency responses are obtained by using high-tension of wire rope. The control performance may improve during the robot operation and, therefore, it is useful to compensate for the vibration effect.

Mitsantisuk, Chowarit; Ohishi, Kiyoshi; Urushihara, Shiro; Katsura, Seiichiro

149

Test wire for high voltage power supply crowbar system  

SciTech Connect

The klystron microwave amplifier tubes used in the Low Energy Demonstration Accelerator (LEDA) and to be used in the Accelerator Production of Tritium (APT) plant have a strict upper limit on the amount of energy which can be safely dissipated within the klystron`s vacuum envelope during a high voltage arc. One way to prevent damage from occurring to the klystron microwave amplifier tube is through the use of a crowbar circuit which diverts the energy stored in the power supply filter capacitors from the tube arc. The crowbar circuit must be extremely reliable. To test the crowbar circuit, a wire that is designed to fuse when it absorbs a predetermined amount of energy is switched between the high voltage output terminals. The energy required to fuse the wire was investigated for a variety of circuits that simulated the power supply circuit. Techniques for calculating wire length and energy are presented along with verifying experimental data.

Bradley, J.T. III; Collins, M.

1997-09-01

150

Beam Emittance Measurement with Laser Wire Scanners in the ILC Beam Delivery System  

SciTech Connect

Accurate measurement of the beam phase-space is essential for the next generation of electron accelerators. A scheme for beam optics optimization and beam matrix reconstruction algorithms for the diagnostics section of the beam delivery system of the International Linear Collider based on laser-wire beam profile monitors are discussed. Possible modes of operation of the laser-wire system together with their corresponding performance are presented. Based on these results, prospects for reconstructing the ILC beam emittance from representative laser-wire beam size measurements are evaluated.

Agapov, I.; /CERN; Blair, G.A.; /Royal Holloway, U. of London; Woodley, M.; /SLAC

2008-02-01

151

Analysis of DC Connection for Capacitor Energy Storage in Wind Power Generation System  

Microsoft Academic Search

This work presents the analysis and performance of connecting two wind power generation systems with the energy storage at the dc side. Energy storage is desirable to be installed to keep constant output from the wind power generation system. The DC connection of two wind power generation system helps to exchange power between the two systems and can suppress the

V. J. Yeshwenth; R. Udhayaprakash; N. Krishna

2008-01-01

152

Thin Wire Modeling for FDTD Electromagnetic Calculations in the Two-Dimensional Cylindrical Coordinate System  

NASA Astrophysics Data System (ADS)

In this paper, the equivalent radius of a thin wire represented using the FDTD method in the two-dimensional (2D) cylindrical coordinate system is identified as 0.135?r, where ?r is the lateral side length of the rectangular cells, while that of a thin wire represented in the 3D Cartesian coordinate system is known to be 0.230?r. Furthermore, it is shown that the technique proposed by Noda and Yokoyama to represent a thin wire having an arbitrary radius in the 3D Cartesian coordinate system can be applied successfully to representing such a thin wire in the 2D cylindrical coordinate system if 0.135?r is used for the equivalent radius instead of 0.230?r.

Taniguchi, Yohei; Baba, Yoshihiro; Nagaoka, Naoto; Ametani, Akihiro

153

Verification Testing of an AH-1S Wire Strike Protection System (WSPS).  

National Technical Information Service (NTIS)

The Applied Technology Laboratory conducted developmental and performance verification tests to determine the suitability for AH-1S application of a Wire Strike Protection System (WSPS) designed and fabricated by Bristol Aerospace Limited and Bell Helicop...

L. T. Burrows

1982-01-01

154

EFFECT OF A HEATED PLATINUM WIRE ON A SEALED CO2 LASER SYSTEM  

Microsoft Academic Search

A heated platinum wire was used in a sealed CO2&sngbnd;N2&sngbnd;He laser system, resulting in increases in output power that were dependent on the initial fill pressure of CO2. The system was also filled with a CO2&sngbnd;He mixture and made to lase. Heating of the platinum wire caused a decrease in output power. It was tentatively concluded that the platinum catalyzes

F. M. Taylor; A. Lombardo; W. C. Eppers

1967-01-01

155

Identification of twin direct-drive motor system with consideration of wire rope tension  

Microsoft Academic Search

An adaptable stiffness of mechanical using wire rope tension control, called as a twin direct-drive motor system, has unique advantages in human-robot interaction system, when compared with conventional industrial robot. Since the wire rope is low friction and lightweight device, it is possible to achieve high-efficiency, high degree of reliability, and safety. In this paper, modeling and closed-loop identification of

Chowarit Mitsantisuk; Kiyoshi Ohishi; S. Urushihara; S. Katsura

2009-01-01

156

NASA requirements and applications environments for electrical power wiring  

NASA Astrophysics Data System (ADS)

While a large data base for electrical arc track-resistant wire insulation exists for aircraft electrical power systems, comparable spacecraft-pertinent data are in limited supply. Existing insulation systems have been found to arc-track at potentials as low as 28 V dc. An account is presently given of the electrical, thermal, mechanical, and operational requirements for specification and testing of candidate wiring systems for spacecraft applications.

Stavnes, Mark W.; Hammond, Ahmad N.

157

Advanced medium-voltage bidirectional dc-dc conversion systems for future electric energy delivery and management systems  

NASA Astrophysics Data System (ADS)

The distributed renewable energy generation and utilization are constantly growing, and are expected to be integrated with the conventional grid. The growing pressure for innovative solutions will demand power electronics to take an even larger role in future electric energy delivery and management systems, since power electronics are required for the conversion and control of electric energy by most dispersed generation systems Furthermore, power electronics systems can provide additional intelligent energy management, grid stability and power quality capabilities. Medium-voltage isolated dc-dc converter will become one of the key interfaces for grid components with moderate power ratings. To address the demand of medium voltage (MV) and high power capability for future electric energy delivery and management systems, the power electronics community and industry have been reacting in two different ways: developing semiconductor technology or directly connecting devices in series/parallel to reach higher nominal voltages and currents while maintaining conventional converter topologies; and by developing new converter topologies with traditional semiconductor technology, known as multilevel converters or modular converters. The modular approach uses the well-known, mature, and cheaper power semiconductor devices by adopting new converter topologies. The main advantages of the modular approach include: significant improvement in reliability by introducing desired level of redundancy; standardization of components leading to reduction in manufacturing cost and time; power systems can be easily reconfigured to support varying input-output specifications; and possibly higher efficiency and power density of the overall system. Input-series output-parallel (ISOP) modular configuration is a good choice to realize MV to low voltage (LV) conversion for utility application. However, challenges still remain. First of all, for the high-frequency MV utility application, the low switching loss and conduction loss are must-haves for high efficiency, while bidirectional power flow capability is a must for power management requirement. To address the demand, the phase-shift dual-halfbridge (DHB) is proposed as the constituent module of ISOP configuration for MV application. The proposed ISOP DHB converter employs zero-voltage-switching (ZVS) technique combined with LV MOSFETs to achieve low switching and conduction losses under high frequency operation, and therefore high efficiency and high power density, and bidirectional power flow as well. Secondly, a large load range of high efficiency is desired rather than only a specific load point due to the continuous operation and large load variation range of utility application, which is of high importance because of the rising energy cost. This work proposes a novel DHB converter with an adaptive commutation inductor. By utilizing an adaptive inductor as the main energy transfer element, the output power can be controlled by not only the phase shift but also the commutation inductance, which allows the circulating energy to be optimized for different load conditions to maintain ZVS under light load conditions and minimize additional conduction losses under heavy load conditions as well. As a result, the efficiency at both light and heavy load can be significantly improved compared with the conventional DHB converter, and therefore extended high-efficiency range can be achieved. In addition, current stress of switch devices can be reduced. The theoretical analysis is presented and validated by the experimental results on a 50 kHz, 1 kW dc-dc converter module. Thirdly, input-voltage sharing and output-current sharing are critical to assure the advantages of the ISOP modular configuration. To solve this issue, an identically distributed control scheme is proposed in this work. The proposed control scheme, using only one distributed voltage loop to realize both input-voltage and output-current sharing, provides plug-and-play capability, possible high-level fault tolerance, and easy implementatio

Fan, Haifeng

158

Magnification of Starting Torques of DC Motors by Maximum Power Point Trackers in Photovoltaic Systems.  

National Technical Information Service (NTIS)

Direct current (dc) motors are used in terrestrial photovoltaic (PV) systems such as in water-pumping systems for irrigation and water supply. Direct current motors may also be used for space applications. Simple and low weight systems including dc motors...

J. Appelbaum S. Singer

1989-01-01

159

A remote wire\\/wireless video monitor system using HW\\/SW co-scheduling RTOS  

Microsoft Academic Search

The remote wire\\/wireless video monitor system (RWVMS) is a video monitor and control system developed successfully by NEUINFO. RWVMS consists of several sub-systems each of them forming a complex independent component. RWVMS covers the task controlling, configuring and monitoring of the system. Since the experiment will be running in a radiation environment, fault tolerance, error correction and system stability in

Hai Xu; Yu Han; Shuisheng Wei; Qingxu Deng; Jin Cui; Shuang Wang; Ge Yu

2005-01-01

160

Transient analysis of an HTS DC power cable with an HVDC system  

NASA Astrophysics Data System (ADS)

The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

2013-11-01

161

NEWS: a net-even-wiring system for the routing on a multilayer PGA package  

Microsoft Academic Search

Given a die with I\\/O pads wire bonded onto the multilayer substrates of a pin grid array (PGA) package, a three-step net-even-wiring system (NEWS) is proposed to complete the routing of the bond pads to the corresponding grid pins on one or more layers. First, we performed a maximum-cut partitioning on a net interference graph for the layer assignment step.

Chia-chun Tsai; Chwan-ming Wang; Sao-jie Chen

1998-01-01

162

A 6kW, 2kWh Lithium-Ion battery energy storage system using a bidirectional isolated DC-DC converter  

Microsoft Academic Search

This paper describes the design and operation of a 6-kW, full-bridge, zero-voltage switching, bidirectional isolated dc-dc converter for a 2-kWh lithium-ion (Li-ion) bank that is considered attractive as an energy storage system for applications to photovoltaic generation systems ranging from 10 to 30 kW. The dc voltage at the high-voltage side of the converter is controlled from 305 to 355

Nadia M. L. Tan; Takahiro Abe; Hirofumi Akagi

2010-01-01

163

DC/AC Circuits: Course Materials  

NSDL National Science Digital Library

This course provided by eSyst describes DC/AC circuits. An introduction explains the traditional view and systems view of this topic. The course includes numerous instructor presentations, student guides, and student learning outcomes. Additional materials are grouped by topic such as circuits, semiconductors, and wiring. Users must create a free, quick login in order to download the materials.

2012-06-28

164

DC link voltage control strategy of grid-connected wind power generation system  

Microsoft Academic Search

In wind power generation systems, the turbulence of the wind will result in power variations and thus affect the DC link voltage ripples and the power quality in the grid. A fuzzy logic controller is designed in this paper for reducing the DC link voltage ripples of the permanent magnet wind power generation system. The simulation model is built under

Jianzhong Zhang; Ming Cheng

2010-01-01

165

Automatic AC/DC Thermal Voltage Converter and AC Voltage Calibration System.  

National Technical Information Service (NTIS)

An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to c...

K. J. Lentner D. R. Flach B. A. Bell

1984-01-01

166

Power flow management strategies for a local DC Distribution System of More Electric Aircraft  

Microsoft Academic Search

The local DC Power Distribution System of More Electric Aircraft has to be able to sustain bidirectional power flow to and from electromechanical devices. Because the mechanical source (Turbine Engine) is unidirectional, some storage and dissipation systems are necessary to store or\\/and dissipate the returned energy to maintain the DC bus voltage to the reference value. Different power management strategies

He Zhang; Fabien MOLLET; Stefan BREBAN; Christophe SAUDEMONT; Benoît ROBYNS

2010-01-01

167

Coordination and Optimization Of HVDC Modulations Using Chaotic Optimization Algorithm in DC\\/AC Power System  

Microsoft Academic Search

A Chaotic Optimization Algorithm (COA) is applied to integrated AC\\/DC hybrid power system in which the multi-infeed DC power transmission system is included, and the research on coordination controls among the HVDC modulations has been investigated in this paper. Chaotic Optimization Algorithms, which have the features of easy implementation, short execution time and robust mechanisms of escaping from local minima,

Zheng Xi-yun; Li Xing-yuan; Wang Yu-hong; Xu Mei-mei; Mu Zi-long; Liu Jian; Wei Wei

2010-01-01

168

An Adaptive Control System for a DC Microgrid for Data Centers  

Microsoft Academic Search

In this paper, an adaptive control system for a dc microgrid for data centers is proposed. Data centers call for electric power with high availability, and a possibility to reduce the electric losses and, consequently, the need for cooling. High reliability can be achieved by using local energy sources, and by using a dc power system, the number of conversion

Daniel Salomonsson; Lennart Soder; Ambra Sannino

2008-01-01

169

A generalized framework for sampled-data model analysis of closed-loop PWM DC-DC converter system  

Microsoft Academic Search

In spite of the fact that, sampled-data models of PWM DC power converter systems (PDCS) are more accurate and natural, little effort has been made to use sampled-data techniques for stability analysis and synthesis of closed-loop PDCS. Instead, averaged models are typically used for control loop design, while detailed simulations are used for validating closed-loop performances. Recent developments in sampled-data

Muhammad Mansoor Khan; Wu Zhi-Ming

2001-01-01

170

A review of distributed power systems part I: DC distributed power system  

Microsoft Academic Search

The present development state in DC distributed power systems (DPS) is comprehensively reviewed in this tutorial. Basic distributed structures and their characteristics are described. The system level design considerations are discussed. The profile of current technologies is drawn. Finally, the issues and challenges in this research area are identified. These issues include not only improving efficiency, but also increased concerns

Shiguo Luo; ISSA BATARSEH

2005-01-01

171

Novel DC ring topology and protection system - a comprehensive solution for mega city power grids  

NASA Astrophysics Data System (ADS)

The development of mega cities leads to increased load concentration and brings additional challenges to managing the electrical grid while keeping power available for critical loads. Techniques using FACTS devices are being applied to alleviate power management difficulties and to confine faults in their originating areas in order to limit the risk of cascading failures in the grid. The addition of many FACTS devices often results in control and protection coordination difficulties, power oscillations between connected networks, subsynchronous resonance problems, and torsional interactions with nearby generator units. The most effective solution is obtained when the individual AC subsystems representing sources and loads are decoupled so a fault in a given subsystem is not propagated to another subsystem. This solution can be achieved by the deployment of a DC system where power sources and loads are connected to the DC bus through voltage source converters. For a mega city, this would be conceived as a DC ring feeding multiple loads and connected to remote and local power sources. Unfortunately, the lack of fast DC circuit breakers has been one of the key issues affecting extensive applications of DC systems with common DC buses; a DC fault would discharge all the capacitors of the DC bus and cause delays in system recovery and possibly a wide system collapse. In this research, I provide a comprehensive solution to mega city power grid problems by proposing a DC system topology that enables grid expansions without affecting existing protection settings or changing existing AC breaker ratings. I also propose the means for protecting the DC system by designing a fast DC breaker and developing a control algorithm capable of isolating DC faults without blocking converter stations or depleting DC bus capacitors. My contribution is three folds: (1) I modeled and simulated Shanghai power grid and performed a study to identify short circuit and voltage stability problems using data provided by ABB corporate research located in China. I built on the work that had been performed in ABB China by considering different contingencies and I applied solutions using individual FACTS devices such as FCL, SVC-LightRTM, and HVDC-LightRTM. I analyzed the results from each solution in order to assess its merits and limitations in dealing with fault current and voltage stability problems. Then I presented a novel DC ring topology that provides redundancy, better protection against cascading faults, and does not increase short circuit levels. With this topology, adding loads or power sources does not impact system protection or performance. (2) I proposed two novel designs for a DC circuit breaker that is of critical importance to DC applications using multiple converter stations. The proposed designs solve the problem of DC fault clearing without causing significant voltage drops, current oscillations, or shutting down of any converter station connected to the DC bus. The DC breaker rated at a voltage of 320 kV and a current of 3000 A can interrupt DC currents as high as 70 kA within 800 mus. (3) I proposed a novel placement of the DC circuit breakers within the DC ring topology combined with an intelligent protection algorithm that optimizes fault detection and isolation without affecting the rest of the DC system. The protection scheme uses local measurements and special coordination techniques for clearing solid faults and uses differential measurements to identify and isolate high impedance faults.

Haj-Maharsi, Mohamed Yassine

172

Grid-connected hybrid PV\\/wind power generation system with improved DC bus voltage regulation strategy  

Microsoft Academic Search

The objective of this paper is to propose an improved dc bus voltage regulation strategy for the grid-connected PV\\/Wind power generation system. The proposed dc bus voltage regulation strategy can reduce the variation of the dc bus voltage and the size of the dc bus capacitor bank, significantly. Also, the change of the injected ac current amplitude will be moderate

Yaow-Ming Chen; Chung-Sheng Cheng; Hsu-Chin Wu

2006-01-01

173

Study on nondestructive detection system based on x-ray for wire ropes conveyer belt  

NASA Astrophysics Data System (ADS)

A nondestructive detection system based on X-ray for wire ropes conveyer belt is designed by X-ray detection technology. In this paper X-ray detection principle is analyzed, a design scheme of the system is presented; image processing of conveyer belt is researched and image processing algorithms are given; X-ray acquisition receiving board is designed with the use of FPGA and DSP; the software of the system is programmed by C#.NET on WINXP/WIN2000 platform. The experiment indicates the system can implement remote real-time detection of wire ropes conveyer belt images, find faults and give an alarm in time. The system is direct perceived, strong real-time and high accurate. It can be used for fault detection of wire ropes conveyer belts in mines, ports, terminals and other fields.

Miao, Changyun; Shi, Boya; Wan, Peng; Li, Jie

2008-03-01

174

Parallel Wire Driven System for Joint Torque Estimation of Human Leg in Passive Motion  

NASA Astrophysics Data System (ADS)

This paper presents a leg torque estimation system for a passive motion that uses an incompletely restrained parallel wire driven mechanism. After comparing completely and incompletely restrained parallel wire driven systems, we organize the characteristics of both systems for human torque estimation. Defining the work spaces of four kinds for the incompletely restrained mechanism, we analyze the realization of passive tracking for a leg. Then we demonstrate that the walking motion can be achieved using low-power actuators. A case example of design is introduced to manufacture a prototype for the leg torque estimation. Finally, the result of the leg torque estimation is presented through experiments conducted using a prototype system.

Kino, Hitoshi; Saisho, Kenichi; Miyazoe, Tsutomu; Kawamura, Sadao

175

Single phase grid-connected PV system with time-sharing modulation and Pi-type regulators for DC-DC boost converter and full-bridge inverter  

Microsoft Academic Search

The paper presents investigation, digital control realization and efficiency evaluations of a single-phase grid connected photovoltaic system, composed of DC-DC boost converter and full-bridge inverter with timesharing modulation. The system is analyzed with the use of Matlab-Simulink and FPGA-based real-time models.

Robert Stala; L. Stawiarski; M. Szarek

2010-01-01

176

Effect of RF interference on characteristics of DC SQUID system  

Microsoft Academic Search

The effects of RF interference on the characteristics of DC superconducting quantum interference devices (SQUIDs) are investigated. The noise of a DC SQUID gradiometer radiating an RF field with a frequency between 100 kHz and 80 MHz was measured. As the RF field strength intensified, the white noise level increased and the cut-off frequency was lowered. The flux-voltage transfer function

N. Ishikawa; K. Nagata; H. Sato; N. Kasai; S. Kiryu

1993-01-01

177

Realization of a virtual sports training system with parallel wire mechanism  

Microsoft Academic Search

We develop a virtual sports training system for “playing catch”. In this system, a force display device using “parallel wire mechanism” is adopted to obtain performance suitable for sports training. We describe the detail of the device used in this system. Furthermore, some basic experimental results demonstrate that it is capable of achieving the high speed performance enough to implement

Tetsuya Morizono; Kazuhiro Kurahashi; Sadao Kawamura

1997-01-01

178

Dynamic fault tree analysis for digital fly-by-wire flight control system  

Microsoft Academic Search

Digital Fly-By-Wire (FBW) Flight Control System (FCS) is designed to achieve high level of reliability, frequently employ high level of redundancy. Dynamic redundancy employed in FEW system can realize complex fault and error diagnosis, recovery and reconfiguration. It is very difficult to analyze the reliability of the FEW system by traditional methods, such as Fault Tree Analysis (FTA) or Network

Yao Yiping; Yang Xiaojun; Li Peiqiong

1996-01-01

179

Development of five-degree-of-freedom wire suspension power-assisted system using linear cylinders  

Microsoft Academic Search

In this paper, a power-assisted attitude control system consisting of parallel wires is proposed. This system controls the attitude of an object, thus reducing the burden on the operator and allowing direct manipulation. In our previous research, a power-assisted control system for an overhead crane was proposed. Operators could move a heavy object freely in horizontal and vertical directions and

Takanori Miyoshi; Kenji Suzuki; Kazuhiko Terashima

2011-01-01

180

Capacity Enhancement for Aging Distribution Systems using Single Wire Earth Return  

Microsoft Academic Search

Single wire earth return systems, (SWER), are the low cost technology for rural power distribution and have global application. In the Australian setting, voltage regulation is becoming the determining factor for older SWER systems. In long systems, directly connected shunt reactors are used to compensate the effects of line to ground capacitance. The replacement of fixed shunt reactors with controllable

P. J. Wolfs; N. Hosseinzadeh; S. T. Senini

2007-01-01

181

Thyristor Controlled Reactor Methods to Increase the Capacity of Single Wire Earth Return Systems  

Microsoft Academic Search

Single wire earth return systems are a widely applied low cost power distribution method used in many rural areas. In Central Queensland a single SWER system supplying approximately 100kW may extend more than 300km. These systems often use shunt reactors to compensate the effects of line to ground capacitance. Recent patterns of load growth are forcing the upgrading of these

Peter Wolfs; Steven Senini; Anthony Loveday; Jon Turner; Rockhampton Australia

182

Characterization and application of Shape Memory Alloy wires for micro and meso positioning systems  

NASA Astrophysics Data System (ADS)

The properties of Shape Memory Alloy (SMA) wires are determined by experimentation, and previously used experimental equipment contributes to measurement errors in data. In this study, various characterization experiments are designed and carried out using a precision characterization instrument for shape memory alloy wires to determine the properties and parameters of the alloy. These experiments demonstrate the behavior of SMA wires under different thermal and loading conditions as they occur in actuation applications. As SMA wires go through phase transformation, a significant amount of contraction force is produced. This actuation force has been used in bias spring actuators and differential actuators. In this dissertation, the force generated during the twinning of martensite is used to actuate positioning systems with small displacements at the micrometer level. A micropositioning system is designed and tested that has a positioning accuracy of about +/-0.15 mum. A relation between the current input and the displacement output is determined for the specific preload. The transformation force generated during the phase change from martensite to austenite is used as an actuation force for a second positioning system that uses linear bearing with a displacement range of about a millimeter. This positioning system actuated with a single nitinol wire and guided by symmetric parallel diaphragm flexures, was designed and tested. The actuation is repeatable to about +/-15 mum with variation of about +/-5 mum in postion at steady temperature.

Khan, Afzal

183

Strata reinforcement with bolting and wire-rope systems - a comparative study  

SciTech Connect

A strata reinforcement system which has been used on an experimental basis in some 60 Indian coal mines over the past 6 years is described. It consists of a system of 'rope stitching' in which wire rope is stretched across the roof of the roadway and the ends are grouted into 1.8 m drill holes. For spans exceedng 3.6 m, grouted bolts with eye hooks are used for additional reinforcement at mid-span. This paper presents the results of a model study to evaluate the relative reinforcement actions of wire-rope and bolting systems.

Raju, N.M.; Ghose, A.K.

1982-04-01

184

An Industrial DC Power Supply System Based on an Inductive Filtering Method  

Microsoft Academic Search

This paper proposes a new direct current (dc) power supply system based on an inductive filtering method for one industrial dc load. The operating mechanism of the new inductive filtering method is analyzed, and then, the harmonic model and the equivalent model are established. Moreover, the impedance conditions for the implementation of the inductive filtering method are presented, and the

Yong Li; Longfu Luo; Christian Rehtanz; Sven Ruberg; Dechang Yang; Jiazhu Xu

2012-01-01

185

Overcurrent Protection in DC Zonal Shipboard Power Systems using Solid State Protection Devices  

Microsoft Academic Search

In this paper, potential solutions to address the protection challenges in DC Shipboard Power Systems (SPSs) have been investigated. Two different options have been considered. The first option involves the use of Solid-State Circuit Breakers (SSCBs) for fault current limiting and interruption. Simulations on a prototype DC SPS have been performed to assess the performance of a SSCB. It is

Mesut E. Baran; Sercan Teleke; Subhashish Bhattacharya

2007-01-01

186

Protection scheme of voltage sourced converters based HVDC system under DC fault  

Microsoft Academic Search

In this paper, the validity of EMTP model for a voltage sourced converter based HVDC system is established by comparing it with the experimental results of AC-DC simulator (analog type). By using this model, a new protection to suppress the overvoltage under DC fault is developed and its effectiveness is demonstrated by EMTP simulations. Moreover, it is shown that this

N. Gibo; K. Takenaka; S. C. Verma; S. Sugimoto; S. Ogawa

2002-01-01

187

Rectifier and DC bus systems design for the copper electrowinning industry  

Microsoft Academic Search

It is noted that the use of DC rectifiers and DC bus systems for the copper electrowinning industry has become more widespread during the last 10 years due to the refinement of the solvent extraction process, which has made electrowinning one of the most cost-effective methods of producing copper. The author discusses some of the design features of the large

R. R. Brown

1989-01-01

188

Intelligent energy saving power system control of telecom DC power plant  

Microsoft Academic Search

This paper presents the design of intelligent energy saving power system controller (IESPSC) in a DC power plant of Korean Telecommunications. From past experience, rectifiers for telecom DC power plants have been very inefficient at light loads. The proposed control scheme offers a “novel load sharing” approach based on the knowledge of each unit's efficiency in parallel rectifiers. Neural networks

J. Y. Choi; I. Choy; T. Y. Kim; S. W. Gu

1996-01-01

189

Experimental Validation of Energy Storage System Management Strategies for a Local DC Distribution System of More Electric Aircraft  

Microsoft Academic Search

The local DC power distribution system of More Electric Aircraft is one of the cores of the electric power transmission. Because the mechanical source (turbine engine) is unidirectional, the system is not totally reversible. Some storage and dissipation systems are necessary to store or\\/and dissipate the returned energy to maintain the dc bus voltage. Different power-management strategies are proposed and

He Zhang; F. Mollet; C. Saudemont; B. Robyns

2010-01-01

190

Effect of a Heated Platinum Wire on a Sealed CO2 Laser System.  

National Technical Information Service (NTIS)

A heated platinum wire was used in a sealed CO2-N2-He laser system, resulting in increases in output power that were dependent on the initial fill pressure of CO2. The system was also filled with a CO2-He mixture and made to lase. Heating of the platinum ...

F. M. Taylor A. Lombardo W. C. Eppers

1968-01-01

191

SSSC circuit model for three-wire systems coupled with Delta-connected transformer  

Microsoft Academic Search

This paper presents a new circuit model of SSSC based on state equations in three-wired systems. SSSC is a series compensator of FACTS family. It injects an almost sinusoidal voltage with variable amplitude and is equivalent to an inductive or a capacitive reactance in series with the transmission line. The analysis of a power electronics system is complex, owing to

G. Abdollahi Sarvi; M. T. Bina

2010-01-01

192

Research on Dynamics Modeling and Genetic Algorithm Optimization of Automobile Steer-By-Wire System  

Microsoft Academic Search

Automobile Steering by Wire (SBW) system is an advanced steering system, which cuts off the mechanical connection between steering wheel and steered wheels. It controls the steering motor to steer front wheels actively so as to improve handling and stabilities and active safety, and controls steering wheel motor to supply the driver with ideal road feel. Driver-vehicle-road closed loop models

Yu Lei-yan; Yun Ping-li; Liu Feng

2009-01-01

193

Parallel Operation of DFIGs in Three Phase Four Wire Autonomous Wind Energy Conversion System  

Microsoft Academic Search

This paper deals with a control algorithm for two parallel operated Doubly Fed Induction Generators (DFIGs) driven by wind turbines in a three phase four wire autonomous system feeding local loads. The proposed Autonomous Wind Energy Conversion System (AWECS) is using back to back connected Pulse Width Modulated (PWM) Insulated Gate Bipolar Transistors (IGBTs) based voltage source converters (VSCs) with

Puneet K. Goel; Bhim Singh; S. S. Murthy; N. Kishore

2009-01-01

194

Transient overvoltages on a three terminal dc transmission system due to monopolar ground faults  

SciTech Connect

Transient overvoltages have been investigated using the Electromagnetic Transients Program (EMTP) for a three-terminal dc transmission system. Pole to ground faults on a dc line were studied to investigate overvoltages on the healthy pole and also on the electrode lines. The effect of providing a metallic neutral conductor in one section of the three-terminal system was also studied, as was the sensitivity of the results to dc filter configuration and to neutral bus capacitance. It was found that the peak overvoltages for the dc line, specifically near the converter stations, are sensitive to the dc filter configuration. The overvoltages near the converter stations were also found to be affected by the neutral bus capacitance.

Wrate, G.T.; Tasinga, I.K.; Low, S.S.; Melvold, D.J. (Dept. of Water and Power, Los Angeles, CA (US)); Thallam, R.S.; Gerlach, D.W.; Chang, J.Y. (Salt River Project, Phoenix, AZ (USA))

1990-04-01

195

Comparison of three phase current source inverters and voltage source inverters linked with DC to DC boost converters for fuel cell generation systems  

Microsoft Academic Search

Three phase current source inverters (CSI) and voltage source inverters linked with a DC to DC boost converter (VSI+BC) are appropriate solutions to convert electrical energy for distributed fuel cell generation systems. The performance of CSI's and VSI+BC's in this application is shown and both topologies are compared to each other concerning their power semiconductor design rating and their semiconductor

M. Mohr; F. W. Fuchs

2005-01-01

196

Brushless DC motor drive based on multi-input DC boost converter supplemented by hybrid PV\\/FC\\/battery power system  

Microsoft Academic Search

This paper describes a novel operation performance of a brushless DC motor (BLDC), fed by a Hybrid Distributed Generation System (HDGS). The HDGS is accompanied with photovoltaic (PV) array, fuel cell stacks and a battery to supply a fixed power for driving a BLDC motor. The HDGS employs a novel multi-input DC boost converter for utilizing DG sources in a

M. R. Feyzi; S. A. Kh. Mozaffari Niapour; F. Nejabatkhah; S. Danyali; A. Feizi

2011-01-01

197

Beamline stability measurements with a stretched wire system in the FFTB  

SciTech Connect

Beamline stability is of great importance for future linear colliders where tolerances generally are in the micron to sub-micron range. A stretched wire system in the sealed FFTB tunnel at SLAC was used to monitor beamline motion with a sub-micron resolution. In future linear colliders low frequency changes of the beamline alignment (< 0.1 Hz) lead to untolerable quasistatical misalignments and betatron oscillations. Since it requires time to correct those errors, it is very important to determine how often corrections are needed. The authors present the measurements, discuss the systematics of the stretched wire system and compare the observations with the ATL-model for ground motion.

Assmann, R.; Salsberg, C. [Stanford Univ., CA (United States). Stanford Linear Accelerator Center; Montag, C. [DESY, Hamburg (Germany)

1996-09-01

198

Power Sharing Control between Load-Side Inverters in DC Microgrid for Super High Quality Electric Power Distribution System  

NASA Astrophysics Data System (ADS)

DC microgrid is a novel power system using dc distribution in order to provide a super high quality electric power. The dc distribution system is suitable for dc output type distributed generations such as photovoltaic and fuel cells, and energy storages such as batteries and electric double layer capacitors. Power is distributed through dc distribution line and converted to required ac or dc voltage by converters placed near loads. Load-side single phase inverters are connected through transformers in order to share active and reactive power. In this paper, a power sharing control scheme was proposed, and the power sharing characteristics were demonstrated by experimental results.

Kakigano, Hiroaki; Nada, Kaho; Miura, Yushi; Ise, Toshifumi; Uchida, Ryohei

199

An integrated dc-dc power converter for use in distributed generation power systems  

Microsoft Academic Search

Distributed generation (DG) power systems are becoming increasingly attractive as alternatives to traditional centralized power systems. Fuel cells are an important resource that can be used in such systems, but power electronic converter interfaces are needed to ensure that fuel cells can provide fixed and regulated output voltages as the output of a fuel cell can vary with load. Given

Pritam Das; Gerry Moschopoulos

2008-01-01

200

Design of DC - DC converter for hybrid wind solar energy system  

Microsoft Academic Search

Environment friendly solutions are becoming more prominent than ever, as a result of the concern regarding the state of our deteriorating planet. This project presents a new system configuration of the front-end converter stage for a hybrid wind\\/photovoltaic energy system. The aim of this project is to implement the converter and inverter for the wind and solar hybrid system. For

Banu M Shagar

2012-01-01

201

Effect of dc electric field on resonant acoustic phonon scattering in two-dimensional electron systems  

NASA Astrophysics Data System (ADS)

We study [1] the effect of dc electric field on transport properties of two-dimensional electron systems in which resonant acoustic phonon scattering dominates linear response resistivity. We observe that dc electric field strongly modifies phonon resonances, transforming resistance maxima into minima and back into maxima. Further, phonon resonances are enhanced dramatically in the non-linear dc response and can be detected even at low temperatures. Most of our observations can be explained by dc-induced (de)tuning of the acoustic phonon resonances and intra-Landau level impurity scattering. We also observe a dc-induced zero-differential resistance state and a resistance maximum which occurs when the electron drift velocity approaches the speed of sound. [1] W. Zhang, M.A. Zudov, L.N. Pfeiffer, and K.W. West, arXiv:0711.1547v1, Phys. Rev. Lett. (accepted for publication).

Zhang, Wenhao; Zudov, Michael; Pfeiffer, Loren; West, Ken

2008-03-01

202

Control effects of steer-by-wire system for motorcycles on lane-keeping performance  

Microsoft Academic Search

This study discusses the control effects of the steer-by-wire (SBW) system for motorcycles on the lane-keeping performance by examining computer simulation with a rider-vehicle system which consists of a simplified vehicle model, a rider control model and the controller of the SBW system. The SBW system, which compensates the rolling angle deviation between the desired rolling angle intended by the

Yoshitaka Marumo; Nozomi Katagiri

2011-01-01

203

78 FR 1 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...  

Federal Register 2010, 2011, 2012, 2013

...of the Washington, DC, Special Wage Schedule for Printing Positions AGENCY: U.S. Office of Personnel Management. ACTION...System special wage schedule for printing and lithographic positions. The final rule incorrectly listed the page number of...

2013-01-02

204

Electrical endurance of Co/Ni wire for magnetic domain wall motion device  

NASA Astrophysics Data System (ADS)

We investigated electrical endurance of perpendicularly magnetized Co/Ni wires, which are a promising candidate material system for current-induced domain wall motion device. Monitoring the wire resistance while applying dc stress is shown to be a promising way to evaluate the electrical breakdown. An electromigration model describes well the observed time-to-failure as a function of temperature and current density. The dc stress current density which leads to 10-yr lifetime with 50% failure at 150 °C was twice as large as the threshold current density for domain wall motion, suggesting that the device with Co/Ni wire is highly durable against electrical stresses.

Fukami, S.; Yamanouchi, M.; Honjo, H.; Kinoshita, K.; Tokutome, K.; Miura, S.; Ikeda, S.; Kasai, N.; Ohno, H.

2013-06-01

205

Identifier-based adaptive neural dynamic surface control for uncertain DC-DC buck converter system with input constraint  

NASA Astrophysics Data System (ADS)

In this paper, an identifier-based adaptive neural dynamic surface control (IANDSC) is proposed for the uncertain DC-DC buck converter system with input constraint. Based on the analysis of the effect of input constraint in the buck converter, the neural network compensator is employed to ensure the controller output within the permissible range. Subsequently, the constrained adaptive control scheme combined with the neural network compensator is developed for the buck converter with uncertain load current. In this scheme, a newly presented finite-time identifier is utilized to accelerate the parameter tuning process and to heighten the accuracy of parameter estimation. By utilizing the adaptive dynamic surface control (ADSC) technique, the problem of "explosion of complexity" inherently in the traditional adaptive backstepping design can be overcome. The proposed control law can guarantee the uniformly ultimate boundedness of all signals in the closed-loop system via Lyapunov synthesis. Numerical simulations are provided to illustrate the effectiveness of the proposed control method.

Chen, Qiang; Ren, Xuemei; Oliver, Jesus Angel

2012-04-01

206

Safety considerations of aerial systems using insulated and covered wire and cable  

SciTech Connect

Insulated and covered wires and cables have been used in aerial applications for over fifty years. Their various constructions, characteristics, and applications are discussed in Design and Application of Aerial Systems Using Insulated and Covered Wire and Cable. Some have suggested that covered wires and cables should be used in general applications solely for the purpose of providing safety to operating personnel and the general public. This paper discusses factors leading to the conclusion that nonshielded, covered conductor should not be installed solely to assure personal safety. The National Electrical Safety Code (NESC) treats covered conductors as bare conductors for purposes of clearances to personnel spaces; such a requirement is strongly supported by this paper.

Landinger, C.C.; McAuliffe, J.W. [Hendrix Wire and Cable, Milford, NH (United States); Clapp, A.L.; Dagenhart, J.B. [Clapp Research Associates, Raleigh, NC (United States); Thue, W.A.

1997-04-01

207

Dynamic analysis and behavior of electric transmission line systems subjected to broken wires  

SciTech Connect

If cascading structural failures are to be prevented in electric transmission line systems, it is necessary for the support structures to be designed to withstand the longitudinal unbalanced loads resulting from the sudden loss of tension in the wires on one side of a support structure. The present design guides and specifications do not give adequate information to the line designer as to the nature and magnitude of the loads which might be expected. For example, one popular design guide merely states...loads imposed by breaking of a wire should reflect experience under realistic conditions. Several recent major failures, such as the total collapse of 64 miles of a line system in Wisconsin, demonstrate that adequate design procedures are not being utilized at the present time. The purpose of the present investigation is to develop an analysis tool to study the behavior of transmission line systems when one or more wires suddenly break. In particular the variation with time of the longitudinal unbalanced loads in the system are considered in order to determine the maximum values for the design of the support structures. The primary emphasis during the investigation has been in the development of a computer program which will perform a dynamic analysis of a general line system after any number of wires are broken. A lumped mass mathematical model is used and the nonlinear equations of motion are solved using four different numerical analysis procedures. The nonlinearity of the system results from the nonlinear sag-tension relationship for the wires and the nonlinear force-swing relationship for the suspension insulators. A limited parametric study has shown that dynamic loads and ground line moments which are more than four times the residual static values can be expected in typical line systems.

Siddiqui, F.M.A.

1981-01-01

208

Single-wire or path-guidance systems and the inherent advantages versus multiwire or signal systems in commercial applications  

NASA Astrophysics Data System (ADS)

One of the most difficult areas in the IVHS field, much effort is being spent on vehicle guidance systems. Recent developments in technology have allowed major upgrades in capabilities and performance of guidance systems originally developed for AGVs. Advances yield a robust, cost effective single wire system. This system has inherent advantages in system simplicity. A Cyplex developed variant of a single wire system has demonstrated high enough immunity to rain and light snow cover that normal (human) safety reductions in speed are more than adequate to stay within the required system performance envelope. This system and its antenna interface have shown the ability to guide the vehicle at slow speeds (10 MPH) with a tracking repeatability of plus or minus 1/8 of an inch. The basic guide and antenna system have been tested at speeds up to 80 MPH. The system has inherently superior abilities for lane changes and precision vehicle placement, such as stopping precisely on location for fully automated refueling operations. The operation of this Cyplex refined or developed system is described and the impact of a system that is commercially viable now for highway and off road use is discussed. A case for single wire systems as a primary guide is made. Single wire systems as a complement to machine vision based and other systems also are discussed.

Kenyon, Chase H.; Murphy, Mike

1995-01-01

209

A multilevel voltage-source converter system with balanced DC voltages  

Microsoft Academic Search

In this paper, a multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as back-to-back interconnection of power systems, large induction motor drives, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the DC capacitors. The problem may be solved by use of additional voltage regulators or separate DC sources. However, these solutions are

Fang Zheng Peng; Jih-Sheng Lai; John McKeever; James Vancoevering

1995-01-01

210

Performance evaluation of DC-OFDM system in China UWB standard  

Microsoft Academic Search

In this paper, we introduce the recently published China Ultra Wideband (UWB) standard defined in China Wireless Personal Area Networks (C-WPAN) working group for its Dual Carrier OFDM (DC-OFDM) system. The pros and cons are discussed for this DC-OFDM system with four band hopping. The requirement for the length of channel estimation symbols in C-WPAN UWB is validated by applying

Zhiwei Lin; Xiaoming Peng; Francois Chin; Pei Liu

2011-01-01

211

Brushless DC Motor Speed Control System of the Walking Aids Machine  

Microsoft Academic Search

In this paper, brushless DC motor is preferred to be the motive force of the electric walking aids machine. We adopt Y connected three-phase full-bridge drive mode as control scheme. Based on the analysis of brushless DC motor three closed-loop control scheme, a control system is designed. The core of the hardware of this system is TMS320F2812 and intelligent power

Wang Xitai; Zhang Xuexiu; Li Lifeng; Liu Bingshan

2009-01-01

212

Load testing of anchors for wire mesh and cable net rockfall slope protection systems  

Microsoft Academic Search

This study presents results of field tests conducted on anchors used to support wire mesh and cable net rockfall protection systems. The load transfer and failure characteristics of these anchors are different from those used in most civil applications in that loads are often applied transversely to the top of tendon rather than axially. The study included vertical as well

Shanzhi Shu; Balasingam Muhunthan; Thomas C. Badger; Robert Grandorff

2005-01-01

213

A system for the measurement of wire-rope defect positions  

Microsoft Academic Search

Electromagnetic tests are nowadays widely employed to early detect defects of metallic wire ropes. Commercial instruments for electromagnetic tests are able to highlight small defects but provide only a rough estimation of their positions. An analysis of the uncertainty contributions that affect the defect position measurements is described in this paper and an improved measurement system is also presented. The

A. Vallan

2004-01-01

214

New Method Based on Immunity Tests for Shield Maintenance of Wired Electronic Systems  

Microsoft Academic Search

Shielding maintenance of a complex cable harnesses which transmit measurement, control, or other type of signals to electronic shielded devices is a difficult and unsolved task in the electromagnetic compatibility community. Several methods have been developed for this purpose during the past years. The vast majority of these methods needs to dismantle and then reconnect the wired electronic system for

Eugenio Perea; Eduardo Zabala; J. Emilio RodrÍguez-Seco

2008-01-01

215

Monitoring of Single Wire Earth Return systems using Power Line Communication  

Microsoft Academic Search

As demand for power increases in rural areas serviced by Single Wire Earth Return (SWER) networks, distribution issues are becoming increasingly evident. Voltage regulation and system capacity concerns are driving utilities toward using smarter compensation devices for network control in an attempt to provide longevity for aging SWER infrastructure. To date, despite increasing complexity in power delivery over SWER, no

D. Gay; A. Thompson; M. T. O. Amanulla; P. Wolfs

2009-01-01

216

An adaptive neuro-fuzzy inference system (ANFIS) model for wire-EDM  

Microsoft Academic Search

A wire electrical discharge machined (WEDM) surface is characterized by its roughness and metallographic properties. Surface roughness and white layer thickness (WLT) are the main indicators of quality of a component for WEDM. In this paper an adaptive neuro-fuzzy inference system (ANFIS) model has been developed for the prediction of the white layer thickness (WLT) and the average surface roughness

Ulas Çaydas; Ahmet Hasçalik; Sami Ekici

2009-01-01

217

The application of function reconfiguration for digital fly-by-wire flight control system  

Microsoft Academic Search

This paper describes a method of function reconfiguration, dealing with the failure of helm control. When a helm of the aircraft fails, how to reconfigure the remaining normal helms to balance the aircraft again is an important problem. This paper introduces a method to solve this problem, and simulates the airplane with a computer. In the Fly-By-Wire flight control system,

Pei Ying; Li Peiqiong; Yao Yiping

1998-01-01

218

Technology for Detecting and Monitoring Conditions That Could Cause Electrical Wiring Systems Fires.  

National Technical Information Service (NTIS)

The purpose of this report was to conduct an in-depth study of technologies to detect and monitor precursory conditions that could lead to or directly cause fires in residential wiring systems in general, and how these technologies could be applied to old...

1995-01-01

219

DC power system having battery voltage equalizer circuit  

SciTech Connect

An equalizer circuit is disclosed for permitting two series 12 volt batteries to supply both 24 volts and 12 volts and which maintains the batteries charged to equal voltages. The equalizer circuit is a regulated DC to DC converter with its output connected across the 12 volt battery which is connected to 12 volt loads and its input connected across either the other battery or the 24 volts of the input series pair of batteries. The reference voltage for the regulator is derived from a voltage dividing circuit which is connected across the 24 volt terminals of the two batteries. The voltage dividing circuit provides a reference voltage which is equal to half the voltage across the sum of the voltages of the two batteries.

Sullivan, J.D.

1984-10-23

220

Application Considerations for SCR DC Drives and Associated Power Systems  

Microsoft Academic Search

A rapid growth of silicon controlled rectifier (SCR or Thyristor) dc drive applications has resulted from the many benefits derived by these equipments where adjustable speed of drive is required. These are areas normally served by conventional Ward Leonard M-G sets as well as eddy-current couplings. However, SCR drives are not exact equivalents of M-G sets and special considerations requiring

Alan P. Jacobs; George W. Walsh

1968-01-01

221

Measurement of kinetic inductance of superconducting wires and application for measuring flux state of Josephson-junction loops  

Microsoft Academic Search

In order to realize strong coupling in a system of multiple flux qubits with a DC-SQUID, the use of kinetic inductance is advantageous because it can be much larger than geometrical inductance for narrow superconducting wires. We measured the inductance associated with narrow Al wires, and estimated the contributions of kinetic and geometrical inductances. The London penetration depth which determines

Y. Shimazu; T. Yokoyama

2004-01-01

222

Design considerations of a cable wiring system for a new medical center to support a future medical imaging system  

NASA Astrophysics Data System (ADS)

Our Medical Center is faced with the problem to design a cable wiring system today, install it by the middle 1990's, and allow for upgrades and enhancements for the next ten to fifteen years. The cable plant must be able to support functions and activities which are poorly defined today, but will include the hospital information system (HIS), a future picture archiving and communication system (PACS), and possibly an electronic patient chart with integrated image data. The cable plant must also connect to a future campus wide Medical Network of the Indiana University Medical center with the first component being a positron emission tomography system (PET) located approximately one mile away. To meet these goals the proposed cable plant will be a structured wire cabling system following existing and proposed standards for building wiring architectures including the Electronics Industries Association (EIA) and the Telecommunications Industries Association (TIA) 568 Commercial Building Wiring Standard and the proposed Federal Telecommunication Standard 1090. The structured wiring system approached has been evaluated with emphasis on the present and future network topologies that can be implemented, the type and size of fiber optic cable to install, and the need to install fiber optic cable to individual workstations.

Witt, Robert M.; Emrich, Jack

1992-07-01

223

Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

Not Available

2010-11-29

224

Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization  

SciTech Connect

Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

Levashov, Michael Y.

2010-12-01

225

Evolution of the Design of a Second Generation FireWire Based Data Acquisition System.  

PubMed

Our laboratory has previously reported on the basic design concepts of an updated FireWire based data acquisition system for depth-of-interaction detector systems designed at the University of Washington. The new version of our data acquisition system leverages the capabilities of modern field programmable gate arrays (FPGA) and puts almost all functions into the FPGA, including the FireWire elements, the embedded processor, and pulse timing and integration. The design is centered around an acquisition node board (ANB) that includes 64 serial ADC channels, one high speed parallel ADC, FireWire 1394b support, the FPGA, a serial command bus and signal lines to support a rough coincidence window implementation to reject singles events from being sent on the FireWire bus. Adapter boards convert detector signals into differential paired signals to connect to the ANB. In this paper we discuss many of the design details, including steps taken to minimize the number of layers in the printed circuit board and to avoid skewing of parallel signals and unwanted bandwidth limitations. PMID:22228135

Lewellen, T K; Miyaoka, R S; Macdonald, L R; Haselman, M; Dewitt, D; Hauck, S

2010-10-30

226

Evolution of the Design of a Second Generation FireWire Based Data Acquisition System  

PubMed Central

Our laboratory has previously reported on the basic design concepts of an updated FireWire based data acquisition system for depth-of-interaction detector systems designed at the University of Washington. The new version of our data acquisition system leverages the capabilities of modern field programmable gate arrays (FPGA) and puts almost all functions into the FPGA, including the FireWire elements, the embedded processor, and pulse timing and integration. The design is centered around an acquisition node board (ANB) that includes 64 serial ADC channels, one high speed parallel ADC, FireWire 1394b support, the FPGA, a serial command bus and signal lines to support a rough coincidence window implementation to reject singles events from being sent on the FireWire bus. Adapter boards convert detector signals into differential paired signals to connect to the ANB. In this paper we discuss many of the design details, including steps taken to minimize the number of layers in the printed circuit board and to avoid skewing of parallel signals and unwanted bandwidth limitations.

Lewellen, T.K.; Miyaoka, R.S.; MacDonald, L.R.; Haselman, M.; DeWitt, D.; Hauck, S.

2011-01-01

227

Three-phase Four-wire Autonomous Wind Energy Conversion System Using Permanent Magnet Synchronous Generator  

Microsoft Academic Search

This article deals with an autonomous wind energy conversion system employing a permanent magnet synchronous generator feeding three-phase four-wire local loads in stand-alone mode without using a mechanical position sensor. The proposed autonomous wind energy conversion system utilizes two back-to-back connected pulse width modulated insulated gate bipolar transistors based voltage source converters with a battery energy storage system at their

Puneet K. Goel; Bhim Singh; S. S. Murthy; Shailendra K. Tiwari

2010-01-01

228

A high-efficiency single-phase three-wire photovoltaic energy conversion system  

Microsoft Academic Search

A single-phase three-wire photovoltaic energy conversion system with single-stage structure using a novel maximum power-point tracking (MPPT) algorithm is presented. An equivalent model of the proposed system is derived to analyze the characteristics of the system and to design the controller. Owing to the linear relation of the PV array parameters versus insolation, the model is easy to analyze. The

Yeong-Chau Kuo; Tsorng-Juu Liang; Jiann-Fuh Chen

2003-01-01

229

Force-Feedback System Design for the Steer-By-Wire: Optimisation and Performance Evaluation  

Microsoft Academic Search

Current state of art power assisted steering systems used in vehicles are hydro-mechanical type systems, i.e. the steering column motion is transmitted and amplified by the main hydraulic circuit by hydro-mechanical means. Electrical versions of such steering systems are gaining success and are beginning to be implanted in most vehicles. Next step is the so-called by-wire concept. This paper presents

David Gualino; I.-J. Adounkpe

2006-01-01

230

Air data failure management in a full-authority fly-by-wire control system  

Microsoft Academic Search

The aim of the air data system, in a full-authority fly-by-wire control system, is the determination of flight parameters, such as pressure altitude, Mach number, angles of attack and sideslip, from measurements of local pressures and of local flow angles on wings or fuselage, provided by a proper set of sensors. The architecture of the air data system is redundant

A. Calia; V. Poggi; F. Schettini

2006-01-01

231

Monitoring and data acquisition system for experimental general aviation fly?by?wire aircraft  

Microsoft Academic Search

A CAN data bus was used in a project of an experimental Fly?by?Wire control system (SPS?1) mounted on board a PZL?110 “Koliber” general aviation aircraft. This solution allows the free communication between flight control computers and individual modules of the system. The monitoring of the bus state and data frames is useful during particular hardware tests, system integration, laboratory and

P. Rzucid?o

2006-01-01

232

A Configuration and Control Method of DC Loop Type Distribution System Including Distributed Generators  

NASA Astrophysics Data System (ADS)

In the large-scale factories like ironworks, many power electronic inverter loads exist, and these inverter loads are connected into ac systems by using rectifiers. On the other hand, DGs (Distributed Generators) such as photovoltaic generators and fuel cells, or ESSs (Energy Storage Systems) such as secondary batteries and SMESs (Superconducting Magnetic Energy Strages), which are dc power sources will be introduced to distribution systems more and more. These are connected into ac systems by using inverters. Therefore, it is expected that some countermeasures to achieve a dc distribution system which can reduce power losses due to rectifiers and inverters, should be developed. In this paper, a dc loop type distribution system is proposed as one of the new dc distribution system configurations. The calculation results of power losses for the dc loop type distribution system are compared with those for an ac distribution system. Moreover, this paper shows configurations and simulation results of the inverter, bi-directional rectifier and PFC (Power Factor Corrector) used in this system.

Saisho, Masaki; Ise, Toshifumi; Tsuji, Kiichiro

233

A bidirectional DC-DC converter for fuel cell electric vehicle driving system  

Microsoft Academic Search

This paper presents a power converter for a fuel cell electric vehicle driving system. A new bidirectional, isolated topology is proposed in consideration of the differing fuel cell characteristics from traditional chemical-power battery and safety requirements. The studied converter has the advantages of high efficiency, simple circuit, and low cost. The detailed design and operating principles are analyzed and described.

Huang-Jen Chiu; Li-Wei Lin

2006-01-01

234

High-efficiency multiple-output DC-DC conversion for low-voltage systems  

Microsoft Academic Search

This versatile power converter controller provides dual outputs at a fixed switching frequency and can regulate either output voltage or target system delay (using an external - filter). In the voltage regulation mode, the output voltage is monitored with an analog-digital (A\\/D) converter, and the feedback compensation network is implemented digitally. The generation of the pulsewidth modulation (PWM) signal is

Abram P. Dancy; Rajeevan Amirtharajah; Anantha P. Chandrakasan

2000-01-01

235

Implementation of a stand-alone photovoltaic system based on decentralized dc-dc converters  

Microsoft Academic Search

This paper presents an alternative for standalone PV systems that performs a decentralized input energy processing with maximum power point tracking and a bidirectional converter to manage the power flux control of the battery bank. Previous works demonstrate that the gain in efficiency can reach up to 16% in situations where one or more photovoltaic panels are shaded, damaged or

Diogo Brum Cândido; Jonatan Rafael Rakoski Zientarski; Rafael Concatto Beltrame; José Renes Pinheiro; Hélio Leães Hey

2009-01-01

236

Department of Energy`s Wire Development Workshop - Superconductivity program for electric systems  

SciTech Connect

The 1996 High-Temperature Superconducting Wire Development Workshop was held on January 31--February 1 at the Crown Plaza Tampa Westshore in Tampa, Florida. The meeting was hosted by Tampa Electric Company and sponsored by the Department of Energy`s Superconductivity Program for Electric Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. Tampa Electric`s Greg Ramon began the meeting by giving a perspective on the changes now occurring in the utility sector. Major program wire development accomplishments during the past year were then highlighted, particularly the world record achievements at Los Alamos and Oak Ridge National Laboratories. The meeting then focussed on three priority technical issues: thallium conductors; AC losses in HTS conductors; and coated conductors on textured substrates. Following in-depth presentations, working groups were formed in each technology area to discuss and critique the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

NONE

1996-06-01

237

Investigation of transmission system voltage flicker due to multiple AC and DC furnace operations  

SciTech Connect

This paper discusses an investigation of transmission system voltage flicker due to the effects of the operation of multiple AC and DC furnaces, harmonic filters, and static var systems. The utility transmission voltages are measured using a unique flicker measurement and evaluation system. The field tests are compared to an analysis of the expected flicker in the system.

Mendis, S.R.; Bishop, M.T.; Do, A.V. [Cooper Power Systems, Franksville, WI (United States). Systems Engineering Group; Boyd, D.M. [Nucor-Yamato Steel, Blytheville, AR (United States)

1995-01-01

238

Study of AC\\/DC power supply system with DGs using parallel processing method  

Microsoft Academic Search

This paper proposes a new AC\\/DC power supply system with DGs using the parallel processing method. The purpose of this system is to supply the power without connecting to the utility gird. The DGs consist of photovoltaic (PV) and wind generators (WG), and the main energy source of this system is the DGs and the UPS battery. When the system

K. Yukita; Y. Shimizu; Y. Goto; M. Yoda; A. Ueda; K. Ichiyanagi; K. Hirose; T. Takeda; T. Ota; Y. Okui; H. Takabayashi

2010-01-01

239

Characteristics of Styrene Removal With an AC\\/DC Streamer Corona Plasma System  

Microsoft Academic Search

This paper reports plasma-induced styrene removal characteristics in air with a homemade ac\\/dc plasma system. The removal efficiency and reaction kinetics are investigated in terms of source specifications, relative humidity (RH), initial concentrations, by-products, and specific plasma energy density. The result shows that, the larger the difference between peak and dc voltages, the better the removal efficiency. For an initial

Xuming Zhang; Jibao Zhu; Xiaoying Li; Zhen Liu; Xianwen Ren; Keping Yan

2011-01-01

240

Design on four-quadrant DC\\/AC converter for wind power flow optimization system  

Microsoft Academic Search

A four-quadrant DC\\/AC converter for wind power flow optimization system is designed. Firstly, the basic idea of wind power flow optimization and control is analyzed. Secondly, working principle of the four-quadrant DC\\/AC converter is explained and its linear small signal mathematical model in the rotating reference frame is constructed. Then, based on the model, control unit consisting of active current

Yanlei Zhao; Lei Zhang; Housheng Zhang

2011-01-01

241

A high temperature superconductor dc SQUID planar gradiometer measurement system for routine inspections  

Microsoft Academic Search

We have developed a high temperature superconductor (HTS) dc SQUID gradiometric measurement system for routine applications in non-destructive evaluations. Low values of the white flux noise and white field gradient noise were measured for gradiometers operating at 77 K. Low frequency noise was suppressed using an ac bias technique, even in a magnetically unshielded environment. First-order planar dc SQUID flip-chip

M. I. Faley; U. Poppe; V. Yu Slobodchikov; Yu V. Maslennikov; K. Urban

2004-01-01

242

Detection of birdcaging in steel wire rope of a hoisting winch system by analysis of load torque and stator current  

Microsoft Academic Search

The aim of this paper is to analyze theoretically and experimentally the stator current of a three phase induction machine and load torque signals in a hoisting winch system, in order to show how they are influenced by the wire rope faulty condition. When the wire rope is subjected to axial and torsional loads, the outer strands can separate from

H. Henao; S. M. J. Rastegar Fatemi; S. Sieg-Zieba; G. A. Capolino

2009-01-01

243

Regulated DC link voltage with smaller DC link capacitor in Peng's generalized theory of instantaneous reactive power  

Microsoft Academic Search

This paper investigates Peng's control strategy in harmonics compensation with the aim to reduce the size of DC link capacitor. A simple design is proposed to achieve the goal, i.e. implementing a DC voltage regulator to estimate the power loss of the converter and feedback that losses into the original Peng's control strategy. A three-phase, four-wire system which couple to

C. L. Toh; M. Molinas; L. E. Norum

2011-01-01

244

A direct control strategy for UPQC in three-phase four-wire system  

Microsoft Academic Search

Based on the p-q-r theory, this paper presents a direct control strategy of unified power quality conditioner (UPQC) used in the nonlinear and unbalance three-phase four-wire system. A algorithm of calculating the series compensation current and shunt compensation voltage in the proposed system is introduced. An analysis of the proposed control strategy and its schematic diagram is described in particular.

Tan Zhili; Li Xun; Chen Jian; Kang Yong; Duan Shanxu

2006-01-01

245

A Wire Patch Cell Exposure System for in vitro Experiments at Wi-Fi Frequencies  

Microsoft Academic Search

In order to study possible biological effects of electromagnetic (EM) fields generated by Wi-Fi devices, an exposure system based on a Wire Patch Cell (WPC) has been designed, fabricated and fully characterized. The system is suitable to expose, in the whole band of the Wi-Fi signal, cell monolayers plated on the bottom of four 35-mm Petri dishes, filled with 2

Alessandra Paffi; Micaela Liberti; Vanni Lopresto; Caterina Merla; Rossella Lodato; Giorgio Alfonso Lovisolo; Francesca Apollonio

2010-01-01

246

Research on control strategy and bench test of automobile Steer-by-Wire system  

Microsoft Academic Search

Steering by Wire system is a revolution of steering system structure and function.lt cuts off the mechanical connection between steering wheel and steered wheels ,controls the steering motor to steer front wheels actively so as to improve handling and stabilities and active safety,and controls steering wheel motor to supply the driver with ideal road feel. First, driver-vehicle-road closed loop models

Yu Lei-yan; Qi Yao-guang; Liu Feng

2008-01-01

247

Flight-control system architecture optimization for fly-by-wire airliners  

Microsoft Academic Search

The design problem of a flight-control system on a large fly-by-wire airliner is to find combinations of actuator(s), power circuit(s), com- puter(s) for each movable, so as to fulfill the constraints imposed by the safety regulations, while keeping the resulting system weight as low as possible. The trend towards more electrical aircraft makes it harder and harder to determine, in

Christophe BAUERand; Kristen LAGADEC; Marcel MONGEAU

248

A fault tolerant fly by wire system for maintenance free applications  

Microsoft Academic Search

The authors describe a triplex primary flight computer system based on a reconfigurable architecture with extensive use of application specific integrated circuits (ASICs). The system comprises fault-tolerant fly-by-wire (FBW) computers which are triplex dissimilar in both software and hardware. These command actuator control electronics (ACE) units via DATAC (ARINC 629) data buses. The FBW computers form the core of the

R. W. Dennis; A. D. Hills

1990-01-01

249

Unique dependability issues for commercial airplane fly by wire systems  

Microsoft Academic Search

The fundamental concept of dependability is applied to the design of commercial airplane FBW systems beyond the lessons learned\\u000a from the NASA FBW and industry\\/military FBW research and development projects. The considerations of generic errors and common\\u000a mode failures play important role for configuring commercial airplane FBW system architectures and the FBW computer architectures.

2004-01-01

250

THE DESIGN OF FLY-BY-WIRE FLIGHT CONTROL SYSTEMS  

Microsoft Academic Search

The design of an advanced Flight Control System (FCS) is a technically challenging task for which a range of engineering disciplines have to align their skills and efforts in order to achieve a successful system design. This paper presents an overview of some of the factors, which need to be considered, and is intended to serve as an introduction to

Chris Fielding

251

Experimental Discussion on a 6-kW, 2-kWh Battery Energy Storage System Using a Bidirectional Isolated DC/DC Converter  

NASA Astrophysics Data System (ADS)

This paper presents an experimental discussion on a 6-kW, full-bridge, zero-voltage switching bidirectional isolated dc/dc converter for a 53.2-V, 2-kWh Li-ion battery energy storage system. The combination of high-frequency switching devices, 600-V/200-A IGBTs and 100-V/500-A MOSFETs with a high-frequency transformer reduces the weight and physical size of the bidirectional isolated dc/dc converter. The dc voltage on the high-voltage side of the converter is controlled in a range of 300V to 355V as the battery voltage on the low-voltage side varies from 50V to 59V. Experimental verification of bidirectional power flow into (battery charging) or out of (battery discharging) the Li-ion battery bank is also presented. The maximal efficiency of the dc/dc converter is measured to be 98.1% during charging and 98.2% during discharging, excluding the gate drive loss and control circuit loss.

Abe, Takahiro; Tan, Nadia Mei Lin; Akagi, Hirofumi

252

Computer simulation of a resonant dc link for advanced launch systems  

NASA Astrophysics Data System (ADS)

The performance of a resonant dc link based actuator power system being built for an advanced launch system application is evaluated for a typical launch scenario using two end-to-end system simulations, one using a digital computer and the other using a hybrid computer. Aspects of system performance from the switching of the power electronic devices to the vehicle aerodynamics are addressed. Using these simulations, it is shown that the resonance dc link actuator adequately stabilize the vehicle against a wind gust during a launch.

Sudhoff, S. D.; Wasynczuk, O.; Krause, P. C.; Kenny, B. H.

253

A three-level DC-DC converter with wide-input voltage operations for ship-electric-power-distribution systems  

Microsoft Academic Search

This paper describes a newly developed 3-level DC-DC converter with wide-input voltage operations for ship-electric-power-distribution systems. The proposed converter is designed with zero-voltage-switching (ZVS) techniques. The operational principles, designs details and performance of the converter are discussed along with soft-switching characteristics and load transients through experimental waveforms. The converter achieved about 95% efficiency over wide 7kW load conditions.

Byeong-Mun Song; Robert McDowell; Andy Bushnell

2003-01-01

254

The optimal control of a constrained drive system with brushless DC motor  

Microsoft Academic Search

The optimal (according to the quadratic performance index) control method of a drive position system with an electronically commutated brushless DC motor is discussed. Initially developed for linear, unconstrained, and undistributed systems, this optimal control method is now applied to a system having constrained state and input variables (e.g. armature voltage, armature current, rotor speed) and unknown disturbances (e.g. load

P. M. Pelczewski; ULRICH H. KUNZ

1990-01-01

255

Design and experimental validation of a DC drive for electromechanical actuator system (EMA)  

Microsoft Academic Search

All the automated control systems contain some sort of Actuators and motors. Mostly Permanent Magnet (PM) motors are used to drive the actuator. The systems having short life span contain brushed DC motors. Various types of controllers can be implemented for a Feedback Control System. Each controller has its own characteristics and constraints and can be selected keeping in view

Farhan Baig; Ali Amir; R. Samar

2009-01-01

256

Variable frequency controlled incremental conductance derived MPPT photovoltaic stand-along DC bus system  

Microsoft Academic Search

An incremental conductance (IC) derived MPPT PV stand-along dc bus system by constant-duty variable frequency control is proposed. Fast matching process to executing MPPT PV system is achieved by a simple control programming. The proposed PV system can provide enough energy to load as well as the battery charging with the residual energy. The feasibility is demonstrated by an example

Guan-Chyun Hsieh; Hung-Liang Chen; Yaohwa Chen; Chee-Ming Tsai; Shian-Shing Shyu

2008-01-01

257

High frequency AC vs. DC distribution system for next generation hybrid electric vehicle  

Microsoft Academic Search

The paper proposes and then demonstrates the viability of high frequency AC (HFAC) for propulsion power distribution system in the next generation advanced electric\\/hybrid vehicle. In justifying this viability, the HFAC system has been studied thoroughly and compared with the traditional DC distribution system with regard to cost, weight, performance and other capabilities after performing component sizing calculation of both

B. K. Bose; Min-Huei Kin; M. D. Kankam

1996-01-01

258

International space station wire program  

NASA Astrophysics Data System (ADS)

Hardware provider wire systems and current wire insulation issues for the International Space Station (ISS) program are discussed in this viewgraph presentation. Wire insulation issues include silicone wire contamination, Tefzel cold temperature flexibility, and Russian polyimide wire insulation. ISS is a complex program with hardware developed and managed by many countries and hundreds of contractors. Most of the obvious wire insulation issues are known by contractors and have been precluded by proper selection.

May, Todd

1995-11-01

259

DC electrical conductivity study of cerium doped conducting glass systems  

NASA Astrophysics Data System (ADS)

The glass samples of composition 60V2O5-5P2O5-(35-x)B2O3-xCeO2, (1 <= x <= 5) were prepared by the conventional melt quench method. The samples were characterized by X-ray diffraction and thermo gravimetric-differential thermal analysis. The glass transition temperature and crystallization temperature determined from TG-DTA analysis. The DC electrical conductivity has been carried out in the temperature range 303-473 K. The maximum conductivity and minimum activation energy were found to be 0.039 Scm-1 and 0.15 eV at 473 K for x=1, respectively.

Barde, R. V.; Waghuley, S. A.

2013-06-01

260

Modeling of DC\\/DC Converter for DC Load Flow Calculation  

Microsoft Academic Search

With the development of power electronic techniques, more and more attention has been paid to DC power systems. This paper analyzes the load flow issues containing DC\\/DC converters in a DC power system. The load flow model of DC\\/DC converters, which considers the power losses and control strategy of the converter, has been presented and integrated into the traditional load

Menghua Zhao; Z. Chen; F. Blaabjerg

2006-01-01

261

Feasibility study of a 270V dc flat cable aircraft electrical power distributed system  

Microsoft Academic Search

This report documents the efforts of a one man-year feasibility study to evaluate the usage of flat conductors in place of conventional round wires for a 270 volt direct current aircraft power distribution system. This study consisted of designing electrically equivalent power distribution harnesses in flat conductor configurations for a currently operational military aircraft. Harness designs were established for installation

M. J. Musga; R. J. Rinehart

1982-01-01

262

DC brushless motor and ITS driving control system  

SciTech Connect

A direct current brushless motor is structured by fixing a ring-shape magnetic rotor to a rotor shaft in one piece by way of the magnet yoke, and by arranging the position of the insulating plate on which the magnetic induction elements for detecting the magnetic field of the rotor magnet, stator windings and the rotor yoke are installed, so as to have the rotor magnet oppose the stator windings across an air gap. The stator windings are composed of delta connection wirings and the windings of each phase are placed on a concentric circle having the rotor shaft at its center and in a position dividing the said circle in equiangular areas. The magnetic induction elements are provided in three with the first, second and third elements being respectively fixed at the positions where their respective phases are advanced by ..pi../6 radian in the electric angle from the respective centers of the first phase, second phase and third phase coils. These magnetic induction elements pick up only the plus-side output signals and let the current flow respectively to the aforesaid three-phased stator windings through an amplifier, whereby they form a driving circuit for driving said rotor shaft.

Hagino, H.; Kotake, E.; Nakamura, K.

1984-03-06

263

Dielectric Breakdown Characteristics of Oil-pressboard Insulation System against AC/DC Superposed Voltage  

NASA Astrophysics Data System (ADS)

This paper describes breakdown characteristics of an oil-pressboard insulation system to a superposition voltage of AC and DC voltages. Although AC electric field is decided by the ratio of the relative permittivity of a pressboard and insulating oil, DC electric field is decided by ratio ? of volume resistivities. From the measurement in this study, 13—78 and 1.8—5.7 are obtained as the volume resistivity ratios ? at temperature of 30°C and 80°C, respectively. The breakdown voltages against AC, DC, and those superposition voltages are surveyed to insulation models. In normal temperature, the breakdown voltage to the superposition voltage of AC and DC is determined by AC electric field applied to the oil duct. Since the ? becomes as low as 2-3 at temperature of 80°C, AC and DC voltages almost equally contribute to the electric field of the oil duct as a result. That is, it became clear that superposed DC voltage boosts the electric field across oil ducts at operating high temperature.

Ebisawa, Yoshihito; Yamada, Shin; Mori, Shigekazu; Ikeda, Masami

264

Clamp-Force Estimation for a Brake-by-Wire System: A Sensor-Fusion Approach  

Microsoft Academic Search

The elimination of a clamp-force sensor from brake-by-wire system designs is strongly demanded due to implementation difficulties and cost issues. In this paper, a new method is presented to estimate the clamp force based on other sensory information. This estimator fuses the outputs of two models to optimize the root-mean-square error (RMSE) of estimation. Experimental results show that the estimator

Stephen Saric; Alireza Bab-Hadiashar; Reza Hoseinnezhad

2008-01-01

265

An Operating and Diagnostic Knowledge-Based System for Wire EDM  

Microsoft Academic Search

\\u000a The selection of machining parameters and machine settings for wire electrical discharge machining (WEDM) depends mainly on\\u000a both technologies and experience provided by machine tool manufacturers. The present work designs a knowledge-based system\\u000a (KBS) to select the optimal process parameters settings and diagnose the machining conditions for WEDM. Moreover, the present\\u000a results supply users of WEDM with beneficial data avoiding

Samy Ebeid; Raouf Fahmy; Sameh Habib

2003-01-01

266

A four-sensor hot-wire probe system for three-component velocity measurement  

Microsoft Academic Search

A velocity measurement system based on a miniature four-sensor hot-wire probe capable of simultaneous three-component measurements\\u000a throughout a wide range of flow angles has been developed. The calibration technique allows measurements to be made throughout\\u000a the acceptance cone of the probe without being restricted by the errors associated with analytic angle response equations.\\u000a This technique is based upon look-up tables

K. S. Wittmer; W. J. Devenport; J. S. Zsoldos

1998-01-01

267

DC-DC converters for electric vehicle applications  

Microsoft Academic Search

An integral part of any modern day electric vehicle is power electronic circuits (PECs) comprising of DC-AC inverters and DC-DC converters. A DC-AC inverter supplies the high power electric motor and utility loads such as air-conditioning system, whereas a DC-DC converter supplies conventional low-power, low-voltage loads. However, the need for high power bidirectional DC- DC converters in future electric vehicles

Dakshina M. Bellur; Marian K. Kazimierczuk

2007-01-01

268

Monitoring of debris flows and landslides by wired and wireless systems. Experiences from the Catalan Pyrenees.  

NASA Astrophysics Data System (ADS)

Sophisticated monitoring of landslides for research purpose has started in the 1990thies in the Catalan Pyrenees. Since then several types of mass movements (large landslides, debris flows, shallow landslides and rock falls) and multiples techniques have been applied. In this contribution, special attention will be given to the debris-flow monitoring system installed since summer 2009 in the Rebaixader catchment, Central Pyrenees. The monitoring system has continuously been improved during the last years and nowadays includes devices studying the three major aspects: 1) initiation, 2) flow dynamics, and 3) accumulation. While some parts of the monitoring network include a traditional wired system, the newer parts were installed using low-power wireless devices. Two major aspects will be discussed. First, results of the Rebaixader monitoring site will be presented. Second, experience regarding the monitoring will be evaluated focussing on technical aspects and the comparison between wired and wireless techniques. In the Rebaixader catchment, 6 debris flows and 11 debris floods were observed between August 2009 and October 2012. Surprisingly, also 4 major rock falls were recorded. The rainfall analysis shows that the debris flows were triggered by short, high-intensity rainstorms with a preliminary threshold of about 15 mm during 1 hour. In addition, there was observed a positive trend between event volume and rainfall amount or intensity. The analysis of the ground vibration signals shows significant differences between the time series recorded at the different geophones. These differences are associated with the geophone location in the channel (distance and material), the mounting or the data acquisition system. For instance, the most downstream geophone, installed in bedrock, shows the clearest debris-flows vibration time series, while the uppermost is the most reliable regarding the detection of rockfalls. An evaluation of wired versus wireless monitoring systems shows that wireless techniques have several advantages. They are generally smaller and due to the wireless condition the selection of the sensor location is not restricted like in the standard wired systems. Additionally, they are simple to install and consume much less power. Importantly, they are also more competitive in terms of pricing versus traditional wired solutions. Nevertheless, the adoption of this new technology has not been straightforward due to the harsh conditions where sensors are usually deployed. The later delayed and complicated the installation of some sensors in the Rebaixader site but allowed us to improve the monitoring solution. Finally, some very recent experiences on the wireless sensor network installed in a shallow landslide in the Pre-Pyrenees confirmed that this technique is a perfect solution not only for monitoring, but also for warning systems.

Hürlimann, Marcel; Abancó, Clàudia; Moya, José; Vilajosana, Ignasi; Llosa, Jordi

2013-04-01

269

High-frequency DC link inverter for grid-connected photovoltaic system  

Microsoft Academic Search

This paper proposes an inverter for the grid-connected photovoltaic system based on the transformerless inverter. This system consists of a high frequency inverter bridge, high frequency transformer, diode bridge rectifiers, a DC filter, a low frequency inverter bridge, and an AD filter. The high frequency inverter bridge switching at 20 kHz is used to generate bipolar PWM pulse, which is

Youngseok Jung; Gwonjong Yu; Jaeho Choi; Juyeop Choi

2002-01-01

270

Design and construction evaluation of a photovoltaic DC LED lighting system  

Microsoft Academic Search

The market demand for commercialization of Photovoltaic (PV) systems depends a lot on the reliability, efficiency and performance of various components within the system. PV panels produce DC power when exposed to sunlight, and an inverter converts this to AC power in a typical solar powered building. Though, PV lighting has existed for a long time it hasn't been very

Jyotsna Bhamidipati

2008-01-01

271

Low-Cost Undergraduate Control Systems Experiments Using Microcontroller-Based Control of a DC Motor  

ERIC Educational Resources Information Center

|This paper presents low-cost experiments for a control systems laboratory module that is worth one and a third credits. The experiments are organized around the microcontroller-based control of a permanent magnet dc motor. The experimental setups were built in-house. Except for the operating system, the software used is primarily freeware or free…

Gunasekaran, M.; Potluri, R.

2012-01-01

272

Evaluation of available transfer capability in AC-DC hybrid power systems using point estimation  

Microsoft Academic Search

In deregulated market, available transfer capability (ATC) is a market signal refers to the capability of a system to transport above already subscribed transmission uses. It can provide significant information for power market participants. This paper deals with the evaluation of ATC for the integration of HVDC link with an AC power system. The computational model of ATC for AC-DC

Junqiang Wei; Gengyin Li; Ming Zhou

2011-01-01

273

DC Power System for Superconducting Coils of Fusion Plasma Test Facility LHD  

Microsoft Academic Search

The Large Helical Device (LHD) is an experimental facility for fusion plasma using a large scale mutually coupled superconducting coil system and it is now operating at the National Institute for Fusion Science. This paper introduces the design and the operation results of the dc power systems to drive these coils. First, the outline of the LHD and the power

Hirotaka Chikaraishi; Sigeyuki Takami; Tomoyuki Inoue; Satoru Sakakibara; Toshifumi Ise; Tomoyuki Haga; Hiroyuki Niwa

2006-01-01

274

System for precision ac-dc difference measurements based on a Programmable Josephson Voltage Standard  

Microsoft Academic Search

A system designed for precision measurement of AC-DC difference of thermal voltage converters in terms of a Programmable Josephson Voltage Standard is under development at the National Measurement Institute, Australia (NMIA), in collaboration with the National Institute of Advanced Industrial Science and Technology (AIST), Japan. The agreement between the new system and the calculable thermal converters is presently better than

I. Budovsky; D. Georgakopoulos; T. Hagen

2010-01-01

275

Classification and Technical Review of DC-AC Inverters for Use in Photovoltaic Power Systems.  

National Technical Information Service (NTIS)

A classification system is presented for stand-alone and utility-interactive dc-to-ac inverters used in photovoltaic systems in the 1-to-100-kVA power range. Additional inverter topologies, noted during the classification process, are introduced. To provi...

E. E. Landsman

1979-01-01

276

High precision automated measuring system for AC-DC current transfer standards  

Microsoft Academic Search

An automated measuring system for AC-DC current transfer standards were developed at the Swedish National Testing and Research Institute (SP). The use of a guard makes intercomparisons with ppm precision possible at frequencies up to 100 kHz. Two multijunction thermal converters are used for evaluating the uncertainty of the system

Karl-Erik Rydler

1993-01-01

277

Unstable particles versus resonances in impurity systems; conductance in quantum wires  

NASA Astrophysics Data System (ADS)

We compute the DC conductance for a homogeneous sine-Gordon model and an impurity system, which in the conformal limit can be reduced to a Luttinger liquid, by means of the thermodynamic Bethe ansatz and standard potential scattering theory. We demonstrate that unstable particles and resonances in impurity systems lead to a sharp increase of the conductance as a function of the temperature, which is characterized by the Breit-Wigner formula.

Castro-Alvaredo, O. A.; Fring, A.

2002-12-01

278

Airworthiness and Flight Characteristics Test of the JOH-6A Light Combat Helicopter Configured with a Wire Strike Protection System.  

National Technical Information Service (NTIS)

A limited airworthiness and flight characteristics test on the JOH-6A Light Combat helicopter (LCH) configured with a wire strike protection system (WSPS) was conducted to substantiate the airworthiness. Tests were conducted at Edwards in four flights tot...

J. L. Webre R. Woratschek E. L. Mitchell R. S. Adler

1983-01-01

279

Composite Superconducting Wires Obtained by High-Rate Tinning in Molten Bi-Pb-Sr-Ca-Cu-O System.  

National Technical Information Service (NTIS)

Long lengths of metal superconductor composites were prepared by passing a copper wire through the bismuth based molten oxide system at a constant speed. The key to successful composite preparation is the high pulling speed involved, which permits minimiz...

A. D. Grosav L. A. Konopko N. I. Leporda

1991-01-01

280

30 CFR 75.803-2 - Ground check systems not employing pilot check wires; approval by the Secretary.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.803-2 Ground check systems not employing pilot check wires; approval by the...

2013-07-01

281

30 CFR 77.803-2 - Ground check systems not employing pilot check wires; approval by the Secretary.  

Code of Federal Regulations, 2013 CFR

...HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.803-2 Ground check systems not employing pilot check wires; approval by the...

2013-07-01

282

An adaptive control system with self-organizing fuzzy sliding mode control strategy for micro wire-EDM machines  

Microsoft Academic Search

This paper aims to develop an adaptive control system for process monitoring, identification, and control in micro wire electrical\\u000a discharge machining (wire-EDM). The proportion of short circuits in the total sparks defined as short circuit ratio is chosen\\u000a as a control parameter for the adaptive control system. Pulse interval of each spark is adjusted in real-time according to\\u000a the discrimination

Mu-Tian Yan

2010-01-01

283

Analysis of zig-zag transformer applying in the three-phase four-wire distribution power system  

Microsoft Academic Search

The load unbalance and the nonlinear loads result in a significant neutral current in the three-phase four-wire distribution power system. The Zig-Zag transformer has been proposed to attenuate the neutral current of the three-phase four-wire distribution power system. In this paper, an analysis is carried out and computer simulation is used to evaluate the performance of the Zig-Zag transformer under

Hurng-Liahng Jou; Jinn-Chang Wu; Kuen-Der Wu; Wen-Jung Chiang; Yi-Hsun Chen

2005-01-01

284

NEPTUNE power system: startup power supply for 10 kV to 400 V Dc-Dc converters  

Microsoft Academic Search

NEPTUNE (North-East Pacific Time-series undersea networked experiments) is an underwater power and communications network for scientific experiments. It is proposed for the ocean floor of the Juan de Fuca tectonic plate in the Northeast Pacific Ocean. In the science nodes connected to NEPTUNE network, 10 kV to 400 V dc-dc converters are used to power various scientific instruments and underwater

Shuai Lu; Mohamed A. El-Sharkawi; Harold Kirkham; Bruce M. Howe

2006-01-01

285

Can an AC (alternating current) electrical system replace the present DC system in the automobile? An investigative feasibility study. I. System architecture  

Microsoft Academic Search

In the aerospace industry, the 400-Hz AC system replaced the DC system, and the latest trend in aerospace industry involves a combination of mixed AC and DC electrical system applications. With more and more equipment in the newer automobiles and a corresponding increase in power requirement, it is anticipated that in the not too distant future higher voltage and\\/or some

M. Abul Masrur; Daryl S. Sitar; V. A. Sankaran

1998-01-01

286

Wire Maze  

NSDL National Science Digital Library

Students gain a basic understanding of electrical circuits. They build wire circuits and pass paperclips through the mazes, trying not to touch the wires. Touching a wire with a paperclip causes the circuit to close, which activates an indicator.

K-12 Outreach Office,

287

DC-bus voltage control for hybrid 4-port high frequency parallel-connected sustainable energy conversion system  

Microsoft Academic Search

In this paper, a performance analysis of a dc-bus voltage control for hybrid parallel-connected sustainable energy conversion system is presented. The hybrid system is the combination of fuel cell (FC), wind turbine, and battery storage via a common dc-bus. These hybrid sources are interfaced to dc- bus through high frequency-based power converters. The main advantages of the proposed topologies are:

Mahmoud M. Amin; Osama A. Mohammed

2011-01-01

288

A novel multicell DC-AC converter for applications in renewable energy systems  

Microsoft Academic Search

This paper presents a novel DC-AC converter for applications in the area of distributed energy generation systems, e.g., solar power systems, fuel-cell power systems in combination with supercapacitor or battery energy storage. The proposed converter is realized using an isolated multicell topology where the total AC output of the system is formed by series connection of several full-bridge converter stages.

Hans Ertl; Johann W. Kolar; Franz C. Zach

2002-01-01

289

Multiterminal DC transmission systems for connecting large offshore wind farms  

Microsoft Academic Search

This paper describes the use of voltage source converter (VSC) based, multi-terminal (MT) HVDC transmission system technology for connecting large doubly-fed induction generator (DFIG) based wind farms, over long distance. The operational principles of the proposed system are described and control strategies for coordinating various grid side converters are proposed, to ensure smooth system operation and power sharing between various

Lie Xu; Barry W. Williams; Liangzhong Yao

2008-01-01

290

A Control Method of a Small-Scale DC Power System Including Distributed Generators  

NASA Astrophysics Data System (ADS)

This paper describes a dc micro-grid system interconnecting distributed power generators. The system consists of five generation and control units; a solar-cell generation unit, a wind-turbine generation unit, a battery energy-storage unit, a flywheel power-leveling unit, and an ac grid-interconnecting power control unit. The control method is proposed for suppressing the circulating current by detecting only the dc grid voltage. This method brings high reliability, high-flexibility and maintenance-free operation to the system. The method pays attention to dc output voltage performance of each unit. Each of the power control unit and the energy-storage unit is controlled to act as a voltage source with imaginery impedance. On the other hand, each of the two generation units is controlled to act as a current source. The power-leveling unit is controlled to act as a current source having the function of frequency selectivity like a high-pass filter. A 10-kW prototype system verifies experimentally the validity and effectiveness of the proposed control method for the dc-grid system.

Ito, Youichi; Yang, Zhongqing; Akagi, Hirofumi

291

An Improved Cold-Wire System for Temperature Measurements in Turbulent Flows  

NASA Astrophysics Data System (ADS)

Improved instrumentation and data analysis procedures for the measurement of fluctuating temperature using cold-wires have been developed. An integrated circuit comprising a low-noise, low-cost, constant-current source, a high-gain amplifier and an analog filter has been designed for use in multi-sensor applications. A lumped-capacitance model of the dynamic response of the cold-wire, accounting for the response of both the sensor element and the supporting prongs, has been developed, predicting the effects of "thermal inertia" and sensor-prong interaction. The model parameters were estimated experimentally, using a pulsed laser beam and a pulsed heating source. A digital filter, based on this model, was applied to the cold-wire signal, in order to boost its high-frequency content. Other improvements were digital removal of line noise and other extraneous, periodic disturbances and digital differentiation with characteristics better than those of first-order finite differencing. The new system has been applied in the measurement of the thermal dissipation in heated turbulent shear flows.

Marineau-Mes, S.; Tavoularis, S.

1996-11-01

292

Fallback level concepts for conventional and by-wire automotive brake systems  

NASA Astrophysics Data System (ADS)

Brake-by-wire represents the replacement of traditional brake components such as pumps, hoses, fluids, brake boosters, and master cylinders by electronic sensors and actuators. The different design of these brake concepts poses new challenges for the automotive industry with regard to availability and fallback levels in comparison to standard conventional brake systems. This contribution focuses on the development of appropriate fallback level concepts. Hardware-in-the-loop (HIL) techniques and field trials will be used to investigate the performance and the usability of such systems.

Retzer, H.; Mishra, R.; Ball, A.; Schmidt, K.

2012-05-01

293

Detection of High-Impedance Arcing Faults in Radial Distribution DC Systems.  

National Technical Information Service (NTIS)

High voltage, low current arcing faults in DC power systems have been researched at the NASA Glenn Research Center in order to develop a method for detecting these 'hidden faults', in-situ, before damage to cables and components from localized heating can...

M. C. Gonzalez R. M. Button

2003-01-01

294

Evaluation of IEC draft standard through dynamic simulation of short-circuit currents in DC systems  

Microsoft Academic Search

In this paper, the authors verify the calculation procedures proposed in the International Electrotechnical Commission (IEC) draft standard for the evaluation of short-circuit currents in DC auxiliary power systems of power plants and substations. The dynamic simulation performed on test networks using the Alternative Transient Program (ATP) is taken as a reference for a comparative analysis of the two approaches

Alberto Berizzi; Andrea Silvestri; Dario Zaninelli; Stefano Massucco

1998-01-01

295

Characteristics of Corona Discharge in an Icicle\\/Iced-plate Electrode System under Negative DC Voltage  

Microsoft Academic Search

This paper presents the results of a series of experiments on the corona discharges occurring at icicle tips under negative DC voltage, using an icicle-iced-plate electrode system. The corona discharge development processes and the responding discharge current pulses were recorded. The influences of the gap distance, the icicle surface state and the freezing water conductivity on the corona inception voltage

M. Farzanehl; J. Zhang; D. Yu; C. Sun; W. Sima; L. Shu

2006-01-01

296

Implementation of a high speed, heavy current, dc switching system. Final report  

Microsoft Academic Search

Laboratory performance of mercury-filled current limiting devices (CLD) used for high speed switching of dc circuits (600 volts and below, up to 1,000 amperes) using a system involving a parallel connected vacuum switch with CLD and an additional series connected vacuum switch was verified. The report details analytical work and field experimental tests to predict and control voltage surges associated

H. B. Hamilton; E. Strangas

1978-01-01

297

B-Factory Intermediate DC Magnet Power Systems Reliability Modeling and Results.  

National Technical Information Service (NTIS)

The B-Factory is a high-energy physics facility for studying matter versus anti-matter asymmetry. It utilizes 200 Intermediate DC power systems, employing 2.5 to 17kW switchmode converters, to supply beam-shaping magnets with regulated current. Redundancy...

P. Bellomo

2001-01-01

298

AN IMPROVED EFFICIENCY PERMANENT MAGNET BRUSHLESS DC MOTOR PV PUMPING SYSTEM  

Microsoft Academic Search

This paper presents the optimal operation of a photovoltaic pumping system. The operation of a permanent magnet brushless DC motor driving a centrifugal pump is investigated. The motor is controlled through a hysteresis current loop and an outer speed loop with a PI type controller. The proportional and integral gains are set to their optimal values. In order to optimise

A. MOUSSI; A. TORKI

299

Graphite electrode DC arc furnace system for treatment of environmentally undesirable solid waste  

Microsoft Academic Search

Summary form only given. A graphite electrode DC arc furnance system has been used to demonstrate that iron basalt soil containing various surrogate nonradioactive materials found on the Department of Energy's atomic energy sites and hospital waste can be reduced to a compact, vitrified, solid material which is environmentally acceptable and will pass TCLP leachate tests. A second graphite electrode

C. H. Titus

1993-01-01

300

Analysis and modeling of a single-phase brushless DC motor drive system  

Microsoft Academic Search

A single-phase brushless DC motor drive system with a bifilar stator winding and asymmetrical stator pole faces is investigated. The form of the permanent-magnet component of the stator winding flux linkage is analyzed considering the asymmetry of the stator pole faces. Equations describing the electromechanical dynamics of the motor are then derived along with an expression for the electromagnetic torque.

J. S. Mayer; O. Wasynczuk

1989-01-01

301

Rectifier and DC bus system design for the copper electrowinning industry  

Microsoft Academic Search

Some of the design features of the rectifier and DC bus system that supply the direct current for the electrowinning process as discussed. As background information, a brief description of the solvent extraction (SX) and electrowinning (EW) process is given. The four basic steps to the SC\\/EW process include leaching, extraction, stripping, and electrowinning. Some of the design features of

R. R. Brown

1990-01-01

302

Analysis of Lightning Transients in a DC Traction Power System of Electrified Railway Using EMTP  

Microsoft Academic Search

This paper presented a modeling procedure for a DC traction power system (TPS) of electrified railway to study lightning transients with EMTP. The TPS included overhead lines, electric cables on the ground, masts and other associated components. The nonlinear ionization characteristic of earth resistance and the flashover characteristic of insulators were taken into account. These models were integrated to represent

Qi-Bin Zhou; Y. Du

2006-01-01

303

Stability analysis on the DC Power Distribution System of More Electric Aircraft  

Microsoft Academic Search

The local DC power distribution system (PDS) of a more electric aircraft is one of the cores of the electric power transmission. Generally, the PDS is made up of small power subsystems designed on their own stand-alone operation. But the interaction between the subsystems (sources and loads) induces some problems of stability. This paper compares the different stability behaviours of

H. Zhang; C. Saudemont; B. Robyns; N. Huttin; R. Meuret

2008-01-01

304

Evaluation of DC electric field measurement by the double probe system aboard the Geotail spacecraft  

NASA Astrophysics Data System (ADS)

We summarize the characteristics of the DC electric field measurement by the double probe system, PANT and EFD-P, aboard Geotail. The accuracy and correction factors for the gain (effective length) and off-set, which depends on ambient plasma conditions are provided.

Kasaba, Y.; Hayakawa, H.; Ishisaka, K.; Okada, T.; Matsuoka, A.; Mukai, T.; Takei, Y.

305

DC offset reduction in phase diversity heterodyne doppler radar system  

Microsoft Academic Search

Continuous wave Doppler radar systems have been used for non-contact detection of human cardiopulmonary activity, and these functions can be used in diverse applications including health care, emergency, military, or security. For reliable and robust sensing, several schemes are applied to overcome deleterious system sensitivity associated with the periodic phase relationship between the received signal and local oscillator. In previous

Byung-Kwon Park; Dragan Samardzija; Victor M. Lubecke; Olga Boric-Lubecke; Tod Sizer

2007-01-01

306

The Model-free Learning Adaptive Control for DC Motor Rotate Speed Systems  

Microsoft Academic Search

The model-free learning adaptive control (MFLAC) approach of a class of SISO nonlinear discrete-time systems based on linearization of tight format is applied to DC motor rotate speed systems . The design of controller is model-free, based directly on pseudo-partial-derivatives (PPD) derived on-line from the input and output information of the motor motion system using novel parameter estimation algorithms. Hardware

Cao Rongmin; Hou Zhongsheng; Huang Jian

2007-01-01

307

Stability Study for a Hybrid AC-DC More-Electric Aircraft Power System  

Microsoft Academic Search

The paper deals with the small-signal stability analysis of aircraft ac frequency-wild power systems representing a real ac-dc hybrid distribution architecture with a multiplicity of actuators, aircraft loads, and bus geometries. The $dq$ modelling approach is applied to derive individual power system component models and to constitute the corresponding generalized power system model as a powerful and flexible stability analysis

K. N. Areerak; S. V. Bozhko; G. M. Asher; L. De Lillo; D. W. P. Thomas

2012-01-01

308

Plugging a molecular wire into photosystem I: reconstitution of the photoelectric conversion system on a gold electrode.  

PubMed

Plug and play: Photoinduced electron transfer occurs from photoexcited P700 in photosystem I (PSI) to a gold surface (see picture). A novel molecular connector system is used, in which an artificial molecular wire, which is assembled on the gold surface, was plugged into PSI by reconstitution. Analysis of the photoelectron transfer kinetics proved both the output of electrons from PSI and the effectiveness of the molecular wire. PMID:19156784

Terasaki, Nao; Yamamoto, Noritaka; Hiraga, Takashi; Yamanoi, Yoshinori; Yonezawa, Tetsu; Nishihara, Hiroshi; Ohmori, Tsutomu; Sakai, Makoto; Fujii, Masaaki; Tohri, Akihiko; Iwai, Masako; Inoue, Yasunori; Yoneyama, Satoshi; Minakata, Makoto; Enami, Isao

2009-01-01

309

A Cost-Effective Production DC\\/RF On-Wafer GaAs FET Measurement System  

Microsoft Academic Search

This paper describes a cost-effective DC and microwave test system for production screening of discrete and process-monitor GaAs FETs. Topics covered include system hardware, test software and data storage, DC error-correction, RF GaAs FET modeling, RF probe card technology, error-correction for common-mode inductance, and on-wafer calibration.

Eric S. Copeland; Matthew Borg; Kevin J. Kerwin

1989-01-01

310

Negative impedance instability compensation in more electric aircraft DC power systems using state space pole placement control  

Microsoft Academic Search

In aerospace power systems, multiple power converters and multiple voltage power systems interact with each other and can result in unstable operation. When a dc-dc converter is loaded with a constant power load, it shows instability. This is because of the negative impedance characteristic of constant power load. Some poles of the converter with a constant power load are in

Seyoung Kim; Sheldon S. Williamson

2011-01-01

311

Design of Performance Driven Self-Tuning PID Control Systems and It's Application for DC-DC Converters  

NASA Astrophysics Data System (ADS)

This paper proposes an adaptive PID controller which is driven by current control performance. The calculations of the PID parameters are based on the generalized minimum variance control(GMVC) algorithm. The current control performance is obtained in an online manner over a user-specified time-window with some overlap. The retuning of PID parameters are only carried out when controller performance deteriorates below a user-specified threshold. Experimental evaluations on the voltage control of the DC-DC converter demonstrates the practicality and utility of this idea.

Ohnishi, Yoshihiro; Ikemoto, Takahiro; Yamamoto, Toru

312

An Improved DC-Link Voltage Control Method for Multiple Grid Connected Converter in Direct Drive Wind Power Generation System  

Microsoft Academic Search

In order to reduce the current of each IGBT and reduce the harmonic current into the grid, a multiple AC-DC-AC full-scale converter which is suitable for high power direct drive wind power generation systems is adopted. The reasons of DC-link voltage fluctuation of the grid connected converter are analyzed. An improved DC-link voltage control method for multiple grid connected converter

Weihao Hu; Yue Wang; Xianwen Song; Zhaoan Wang

2009-01-01

313

Impact of quasi-dc currents on three-phase distribution transformer installations. Power Systems Technology Program  

Microsoft Academic Search

This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary

B. W. McConnell; P. R. Barnes; F. M. Tesche; D. A. Schafer

1992-01-01

314

DC Magnetization System for a 35 kV\\/90 MVA Superconducting Saturated Iron-Core Fault Current Limiter  

Microsoft Academic Search

A dc magnetization system, comprises a HTS dc bias coil, a current source, a high-speed switch, and an energy release circuit, was built for a 35 kV\\/90 MVA saturated iron-core fault current limiter to enhance its functional capability and reliability and to reduce its size and weight. The dc bias coil is made of high temperature superconducting silver sheathed Bi-2223

Hui Hong; Zhengjian Cao; Jingyin Zhang; Xiaoming Hu; Jianzhong Wang; Xiaoye Niu; Bo Tian; Yang Wang; Weizhi Gong; Ying Xin

2009-01-01

315

Basic Wiring.  

ERIC Educational Resources Information Center

|This module is the first in a series of three wiring publications; it serves as the foundation for students enrolled in a wiring program. It is a prerequisite to either "Residential Wiring" or "Commercial and Industrial Wiring." The module contains 16 instructional units that cover the following topics: occupational introduction; general safety;…

Kaltwasser, Stan; And Others

316

A multilevel voltage-source converter system with balanced DC voltages  

NASA Astrophysics Data System (ADS)

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 be solved by use of additional voltage regulators or separate dc sources. However, these solutions are found not to be practicable for most applications. The proposed converter system can solve the voltage unbalance problem of the conventional multilevel voltage-source converters, without using any additional voltage balance circuits or separate voltage sources. Mechanism of the voltage unbalance problem is analyzed theoretically in this paper. The validity of the new converter system is demonstrated by simulation and experiment.

Peng, Fang Zheng; Lai, Jih-Sheng; McKeever, John; Vancoevering, James

1995-05-01

317

Recovery semantics for a DB\\/DC system  

Microsoft Academic Search

Presented is a unified, systematic view of integrity\\/recovery as it relates to a data-processing system—whether man, machine, or both. The concept, sphere of control (SOC), as a bound around a process, is developed to permit describing and solving many of the rather aggravating problems of auditability, repeatability, reproducibility, scheduling, consistency, recovery and general integrity. Identified are the relationships among resources

Charles T. Davies Jr.

1973-01-01

318

The SpaceWire-based thermal infrared imager system for asteroid sample return mission HAYABUSA2  

NASA Astrophysics Data System (ADS)

Thermal infrared imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C class near-Earth asteroid 1999JU3 considered to contain organic or hydrated materials. The system consists of a thermal-infrared imager (TIR) and a digital electronics, which is used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement. Since round trip communication time between the asteroid and the Earth is more than thirty minutes, onboard automatic data processing function and high speed data recording capability are provided to exploit the limited downlink capacity which is up to 32kbps. TIR adopts an uncooled bolometer with 320 x 240 effective pixels. Image operations as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce restriction on storage capacity and operation time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high speed data recorder is also connected through SpaceWire in 50Mbps in order to record TIR data in parallel with other sensor data. The modularity of SpaceWire enables to use as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki.

Otake, Hisashi; Okada, Tatsuaki; Funase, Ryu; Hihara, Hiroki; Sano, Junpei; Iwase, Kaori; Kashikawa, Ryoichi; Higashino, Isamu; Masuda, Tetsuya

2013-09-01

319

A unity power factor resonant AC\\/DC converter for high frequency space power distribution system  

Microsoft Academic Search

This paper presents analysis and design of a resonant AC\\/DC converter topology, suitable for use in an advanced single-phase, sine-wave voltage, high-frequency power distribution system, of the type that was proposed for a 20 kHz Space Station Primary Electrical Power Distribution System. The converter comprises a transformer, a double tuned resonant network comprising of series tuned and parallel tuned branches,

P. Jain; M. C. Tanju

1994-01-01

320

AC-DC converter minimizing induced harmonics in industrial power systems  

SciTech Connect

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 capacitor. This study is applied to single-phase powerful electric locomotives. Equivalent three-phase systems are not so interesting.

Destobbeleer, E.; Seguier, G.; Castelain, A.

1987-10-01

321

Comparative performance evaluation of advanced AC and DC EV propulsion systems  

Microsoft Academic Search

Idaho National Engineering Laboratory (INEL) evaluates EV propulsion systems and components for the U.S. Department of Energy (DOE) Electric and Hybrid Vehicle (EHV) Program. In this study, experimental data were used to evaluate the relative performances of the benchmark Chrysler\\/GE ETV-1 DC and the Ford\\/GE First Generation Single-Shaft AC (ETX-I) propulsion systems. Tests were conducted on the INEL's chassis dynamometer

R. D. MacDowall; R. L. Crumley

1988-01-01

322

Overcurrent Protection on Voltage-Source-Converter-Based Multiterminal DC Distribution Systems  

Microsoft Academic Search

This paper proposes a protection scheme which utilizes modern voltage-source converters as fast-acting current-limiting circuit breakers. This paper investigates the main challenges of detecting and localizing a fault, and interrupting it as quickly as possible in a multiterminal dc system. A system protection scheme consisting of smart relays associated with converters has been developed. The protection relays monitor local quantities

Mesut E. Baran; Nikhil R. Mahajan

2007-01-01

323

Uprated dc power system and thermal-hydraulic facilities at Columbia University. Final report  

Microsoft Academic Search

The necessity of carrying out large scale nuclear thermal-hydraulic simulations is increasing. Such experiments call for large power sources, and to meet those requirements the D.C. power system at the Heat Transfer Research Facility of Columbia University has been upgraded to 11.5 MW. The uprated system, its installations, various subsystems, and operations are described. The thermal-hydraulic loops and their auxiliary

W. E. Hovemeyer; S. R. Sreepada; J. E. Casterline

1978-01-01

324

Precision AC–DC Difference Measurement System Based on a Programmable Josephson Voltage Standard  

Microsoft Academic Search

A system designed for precision measurement of ac-dc difference of thermal voltage converters in terms of a pro- grammable Josephson voltage standard is under development at the National Measurement Institute, Australia, in collaboration with the National Institute of Advanced Industrial Science and Technology, Japan. The agreement between the new system and calculable thermal converters is presently better than 0.5 ?V\\/V

Ilya Budovsky; Dimitrios Georgakopoulos; Thomas Hagen; Hitoshi Sasaki; Hirotake Yamamori

2011-01-01

325

Study on the mechanical properties of TiNi shape memory alloy wires using mark shearing system  

NASA Astrophysics Data System (ADS)

The Shape memory alloys (SMAs) wires have been used for medical and engineering filed due to the shape memory effect and the superelasticity effect. It is necessary to measure the mechanical properties of the SMA wires accurately. In this paper the mechanical properties of the shape memory alloy wires with different diameters were studied by a self-made testing system. A loading apparatus driven by step motor was used to apply load, and a load cell with the accuracy of 10 mN and the capacity of 90N was used to measure the value of the load. An optical extensometer based on the mark shearing method was used to measure the strain of the SMA wires, which had accuracy with 5 micron-strains in strain measurement. The mechanical properties of the shape memory alloy wires were studied. The nominal stress-strain curves of the SMA wires were acquired. The superelasticity effect was also studied. The successful experimental results also demonstrated the feasibility of the system in silk-like specimen measurement.

Hua, Tao; Xie, Huimin; Dai, Fulong; Chen, Pengwan; Huang, Fenglei

2009-12-01

326

Distributed image processing system for the monitoring of hot steel wire  

NASA Astrophysics Data System (ADS)

In a prototype for monitoring hot steel wire different technologies are integrated to achieve a robust, flexibly configurable and scalable imaging system. It is designed as a distributed system with private network and Tuplespace communication implementable on a LINUX Server. Intelligent cameras grab and process the image data. For real time communication between the cameras and standard industrial I/O-modules (IEC-61131) MODBUS/TCP messaging is applied. A switch with integrated firewall makes services available to the supervisory control system. Results are available as XML-logfiles. The image processing defines the upper and lower edges of the material by minimum/maximum filtering of the y-gradient. Dual Grassmanian coordinates are used to fit two parallel lines to the edge points by singular value decomposition. This gives the distance between the lines and the confidence interval of each measurement simultaneously, whereas latter is used to reject poor data. Changes of the distance are analysed computing local central moments. Presently, 12 images per second are acquired. The application is able to detect spontaneous rotation of the wire around the axis of rolling directly at the rolling stands and treats also poor images (due to steam of cooling water). It indicates resulting defects, which may go undetected otherwise.

O'Leary, Paul; Weiss, Michael; Schiller, Arnulf

2003-05-01

327

Seating patterns on the Washington, DC Metro Rail System.  

PubMed Central

Research on human tolerance in crashes has found that rear-facing seating offers increased protection over forward seating. However, rearward seats are only available in limited settings. In this study, passengers were observed and seating preferences recorded on the Washington Metropolitan Rail System (Metro). Only 25 per cent of adults faced rearward compared to 66 per cent of children. Since children appear willing to face rearward, rear-facing seating in school buses and other vehicles might be acceptable to them and provide safety benefits as well.

Trinkoff, A M

1985-01-01

328

A high temperature superconductor dc SQUID planar gradiometer measurement system for routine inspections  

NASA Astrophysics Data System (ADS)

We have developed a high temperature superconductor (HTS) dc SQUID gradiometric measurement system for routine applications in non-destructive evaluations. Low values of the white flux noise and white field gradient noise were measured for gradiometers operating at 77 K. Low frequency noise was suppressed using an ac bias technique, even in a magnetically unshielded environment. First-order planar dc SQUID flip-chip gradiometers were used in the measurement system for stable operation under electromagnetically noisy conditions. A synchronous filter was employed to remove all harmonic components of parasitic line frequency interference. This improved the resolution of the system in a typical laboratory or industrial environment showing strong magnetic gradients of the line frequency signal due to nearby metallic constructions. Test scans of contaminations with magnetic particles were performed.

Faley, M. I.; Poppe, U.; Slobodchikov, V. Yu; Maslennikov, Yu V.; Urban, K.

2004-05-01

329

A one-wire'' battery monitoring system with applications to on-board charging for electric vehicles  

SciTech Connect

A novel on-board charge system which utilizes a One-Wire'' system for voltage monitoring is discussed and test results obtained using the system are presented. The system consists of a 20 kHz high frequency charger, an algorithm for charging lead-acid batteries with gelled electrolyte, such that gassing is avoided, the control system to implement this charge algorithm and a one-wire battery monitoring system to provide cell/module voltage information to the battery charge controller. Prototype elements of the system have been tested and the system was installed into an EVA Pacer electric vehicle. Charge tests are performed and data taken with the system installed. All elements of the system functioned properly under user conditions. In particular, the charger demonstrated good efficiency, near unity power factor and full programmability. The charge controller functioned reliably and without flaw. The one-wire monitoring system which permits monitoring of cell/module voltages in a battery pack without an extensive conventional wire harness has proven effective and voltage measurements have taken fast enough for control of charging. It was found that for the purpose of voltage monitoring under driving conditions, the system in its present form is too slow.

Nowak, D. (Alabama Univ., Huntsville, AL (USA). Kenneth E. Johnson Research Center)

1990-10-08

330

Brushless DC motor control system responsive to control signals generated by a computer or the like  

NASA Astrophysics Data System (ADS)

A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

Packard, D. T.

1985-04-01

331

Molecular Spintronics: Theory of Spin-Dependent Electron Transport in Fe/BDT/Fe Molecular Wire Systems  

NASA Astrophysics Data System (ADS)

Metal/Molecule/Metal junction systems forming molecular wires are currently the focus of intense study. Recently, spin-dependent electron transport in molecular wires with magnetic Ni electrodes has been studied theoretically, and spin-valve effects have been predicted.* Here we explore theoretically another magnetic molecular wire system, namely, ferromagnetic Fe nano-contacts bridged with 1,4-benzene-dithiolate (BDT). We estimate the essential structural and electronic parameters for this system based on ab initio density functional calculations (DFT) for some simple model systems involving thiol groups and Fe clusters as well as semi-empirical considerations and the known electronic structure of bulk Fe. We then use Lippmann-Schwinger and Green's function techniques together with the Landauer formalism to study spin-dependent transport. *E. G. Emberly and G. Kirczenow, Chem. Phys. 281, 311 (2002); R. Pati, L. Senapati, P.M. Ajayan and S.K. Nayak, Phys. Rev. B68, 100407 (2003).

Dalgleish, Hugh; Kirczenow, George

2004-03-01

332

Digital Wires  

NASA Astrophysics Data System (ADS)

We study hardware implementations of cellular automata as reliable, adjustable, and secure commication lines. We discuss energy efficient digital wires on a nano-scale, all-optical digital wires, and digital wires as power lines and present performance data of a prototype digital wire, a six cells wide and ten cells long Boolean network. We show that digital wires have the following advantages: (i) Fixed pulse shape (pulses have a rectangular shape with a constant height and a constant width and produce no echos); (ii) Robust against electric smog. Digital wires based on semiconductor technology are effectively inert against electro-magnetic radiation, except for low-frequency radiation (heat) and high frequency radiation (X-rays). Digital wires based on plasma technology have in addition a very high tolerance for heat and X-rays. In digital wire the pulse speed can be rapidly adjusted. Signals on digital wires can be encrypted. Some digital wires can be used as general purpose computers. The data and the code are the input of the wire. Then both travel along the wire and `collide'. The collision is the computation. The result travels to the end of the wire, for further processing, as parallel input by a CPU, an actuator, or another digital wire.

Brown, Benny; Hubler, Alfred

2009-03-01

333

[The VB system: a new modular osteosynthesis material involving both screws and wires].  

PubMed

VB is an osteosynthesis system for the stabilisation of small fragments, which combines the benefits of both wires and screws. It is a modular system comprising a threaded pin and a ring. The threaded pin is first positioned. Then a ring is grasped and opened by the progressive angulation of a screwdriver. Still anchored on the screwdriver, the ring slides easily on the pin. It is clamped on the pin by simply removing the screwdriver and the pin is then cut. This modular system includes 1.8 and 1.1 mm pins and different types of rings (threaded or non threaded, with or without collars). The system is easy to handle and can be introduced using an open or percutaneous technique, allowing compression or distraction. Our preliminary series, performed in accordance with National clinical trial protocol (Huriet) consisted of 50 cases in 24 patients (five women and 19 men) with an average age of 48 years, and a follow-up of more than six months. Fourteen cases of fractures (28 implants) were treated as emergencies (two radial heads, one capitellum, one trochlea of the humerus, seven distal radius fractures, one trapezium, two metacarpals) and 12 cases (22 implants) were elective cases: arthrodesis (one trapezo-metacarpal, one intermetacarpal, two interphalangeal, two carpal), non-union (six scaphoids, one phalangeal) and one phalangeal malunion. Hardware removal was performed in 16 cases. No implant failure has been detected. One case, a DIP arthrodesis, had a suspicion of sepsis which led to the removal of the implants at six weeks. The results of this study have convinced us of the merits of the system, which combines the advantages of both wires and screws. The system allows the user to perform either distraction or compression, and to adjust the force by hand. Compared to the fixed amount of compression produced by lag screws, this feature seems to be a real step forward. PMID:11885383

Dubert, T; Valenti, P; Dinh, A; Osman, N

2002-01-01

334

Role of surface charges in dc gas-discharge systems with high-ohmic electrodes  

NASA Astrophysics Data System (ADS)

Surface charge of the electrodes is investigated for planar dc gas-discharge systems. Both analytical estimates and experimental data show that such a charge plays an important role for the dc systems with a high-ohmic electrode. This is demonstrated by several experiments concerning discharge establishment and pattern formation phenomena. The surface charge has an inhibitory role, as it diminishes the electric field in the gas. Due to the low mobility of the surface charges, their distribution can be nonuniform giving rise to the observable filamentary structure of the discharge. It is also shown that the surface charge effect can be naturally incorporated in existing phenomenological models of the planar discharge. Thereby one can explain several observable phenomena, such as stability, multiplicity, and motion of the localized structures.

Gurevich, E. L.; Liehr, A. W.; Amiranashvili, Sh.; Purwins, H.-G.

2004-03-01

335

Use of a DC SQUID receiver preamplifier in a low field MRI system  

Microsoft Academic Search

We have used tuned receiver coils coupled to a dc SQUID preamplifier in a small scale magnetic resonance imaging (MRI) system operating at 425 kHz (B0=0.01 T). The coil and SQUID are cooled to 4.2 K in a modified biomagnetic cryostat. The modifications provide transparency to rf signals originating outside the cryostat while maintaining an acceptably low liquid helium boiloff

H. C. Seton; D. M. Bussell; J. M. S. Hutchison; D. J. Lurie

1995-01-01

336

High-current density DC magenetohydrodynamics micropump with bubble isolation and release system  

Microsoft Academic Search

One of the major challenges for integrated Lab-on-a-Chip (LOC) systems is the precise control of fluid flow in a micro-flow\\u000a cell. Magnetohydrodynamics (MHD) micropumps which contain no moving parts and capable of generating a continuous flow in any\\u000a ionic fluid offer an ideal solution for biological applications. MHD micropumping has been demonstrated by using both AC and\\u000a direct current (DC)

Bao Nguyen; Samuel Kinde Kassegne

2008-01-01

337

Modeling and Simulation of Voltage Source Converter–Medium-voltage DC System for Stability Analysis  

Microsoft Academic Search

This article presents the modeling and simulation of a simple two-terminal and a multi-terminal voltage source converter based medium-voltage DC system, representing a simplified shipboard distribution network, for angular stability analysis. The control modes considered for the voltage source converter include the voltage control mode and the active and reactive power control schemes. The impact of these control modes on

Seetharama Rudraraju; Suresh C. Srivastava; Anurag K. Srivastava; Noel N. Schulz

2011-01-01

338

Characterization of the CEBAF 100 kV DC GaAs photoelectron gun vacuum system  

Microsoft Academic Search

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps.

M. L. Stutzman; P. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; G. R. Myneni; M. Poelker

2007-01-01

339

Dc bias system of a 35 kV\\/90 MVA saturated iron core SFCL  

Microsoft Academic Search

Saturated iron core superconducting fault current limiter (SIC-SFCL) is a promising fault current limiting device for high or extra-high voltage power grids. It has low impedance in normal power transmission and turns high impedance when a short-circuit takes place. The dc bias system of a saturated iron core superconducting fault current limiter plays a key role in realizing these features.

Yuwei Sun; Weizhi Gong; Jianzhong Wang; Hui Hong; Bo Tian; Ying Xin

2011-01-01

340

Non-linear dc response in microwave-irradiated two-dimensional electron systems: interplay between ac and dc induced effects  

NASA Astrophysics Data System (ADS)

We study nonlinear dc response of a high-mobility two- dimensional electron system subject to microwave (ac) excitation and weak magnetic fields. Recent experiments [1] studied resistance at different dc excitations as a function of the ratio of the microwave frequency to the cyclotron frequency, . Here, we examine oscillations in microwave photoconductivity as a function of dc excitation, at different values of . We find that, for the most part, the oscillation period is the same as in the dark resistivity, and the phase is determined by microwave-induced oscillations at zero dc bias, consistent with the earlier results. However, at some excitation values previously associated with resistance maxima, this approach revealed resistance minima indicating saddle points in the resistivity. We further observed that the oscillation amplitude itself oscillates as a function of , with the oscillations strongly suppressed near half-integral values. These findings indicate the limitations of the simplified resonant condition proposed in Ref. 1 and might stimulate further theoretical studies. [1] W. Zhang, M.A. Zudov, L.N. Pfeiffer, and K.W. West, Phys. Rev. Lett. 98, 106804 (2007)

Hatke, Anthony; Zhang, Wenhao; Zudov, Michael; Pfeiffer, Loren; West, Ken

2008-03-01

341

Percutaneous transluminal coronary angioplasty using a combined "balloon-on-a-wire" system and exchange guidewire technique.  

PubMed

New balloon-on-a-wire dilation systems allow crossing of severely stenosed coronary arteries owing to their ultra-low profile. However, these systems do not allow for over-the-wire exchange to a larger balloon catheter or insertion of perfusion catheters, should the vessel close abruptly during dilation. Therefore, if the need for such catheters arises, the vessel must be left unprotected during attempts to recross the lesion. We describe a new technique using a combined balloon-on-a-wire system and an exchangeable guidewire, which permits the crossing and dilation of severely stenosed coronary arteries, while at the same time offering vessel protection and balloon catheter exchange. PMID:2590937

de Marchena, E; Stang, R B; Schob, A; Topaz, O; Chakko, S; Mallon, S; Kessler, K M

1989-11-01

342

LANSCE-R WIRE-SCANNER ANALOG FRONT-END ELECTRONICS  

SciTech Connect

A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments Compact RIO (cRIO) module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal dataacquisition system, and wire bias of 0V to +/-50V. The AFE system is designed to accommodate comparatively long macropulses (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.

Gruchalla, Michael E. [Los Alamos National Laboratory

2011-01-01

343

The successful evaluation of a 400 kV composite ground wire optical communication system  

NASA Astrophysics Data System (ADS)

In electricity supply industries the environment for communication is extremely hostile. Communication for the safe and efficient operation of the supply system must be error free, particularly during disturbances when intense bursts of electrical radiation and large variations in ground potential are present. The Central Electricity Generating Board, recognizing the potential that optical communication could offer, embarked in 1976 on a period of research into optical communication over high voltage lines. As a result, the world's first fully engineered system was installed, in 1982, when the ground wire on a 400 kV transmission line was restrung using a composite conductor. The installation of the 34Mb/s 1300nm optical - pcm link was carried out jointly with BICC and Plessey. Subsequent experience, particularly 400 kV fault throwing tests, has proved its immunity to any form of interference.

Bronsdon, John A.; Carter, Chris N.; Kent, Alan H.; Iddin, Ardel

1986-11-01

344

Development of hand rehabilitation system for paralysis patient - universal design using wire-driven mechanism.  

PubMed

We have developed a hand rehabilitation system for patients suffering from paralysis or contracture. It consists of two components: a hand rehabilitation machine, which moves human finger joints with motors, and a data glove, which provides control of the movement of finger joints attached to the rehabilitation machine. The machine is based on the arm structure type of hand rehabilitation machine; a motor indirectly moves a finger joint via a closed four-link mechanism. We employ a wire-driven mechanism and develop a compact design that can control all three joints (i.e., PIP, DIP and MP ) of a finger and that offers a wider range of joint motion than conventional systems. Furthermore, we demonstrate the hand rehabilitation process, finger joints of the left hand attached to the machine are controlled by the finger joints of the right hand wearing the data glove. PMID:19963950

Yamaura, Hiroshi; Matsushita, Kojiro; Kato, Ryu; Yokoi, Hiroshi

2009-01-01

345

Superconducting wire.  

National Technical Information Service (NTIS)

This invention consists of a method of producing superconducting wire by drawing a glass fiber with a melted powder of a superconducting wire inside the glass tube. After drawing, the glass fiber is heated to crystallize the superconducting compound. The ...

D. E. Day J. J. Petrovic F. D. Gac C. S. Ray

1991-01-01

346

Magnetic properties of glass ceramic wire in Fe3O4-TiO2SiO2 system  

Microsoft Academic Search

A glassy composite magnetic wire was prepared by elongation during quenching phase-separated melt in two-liquids stable immiscibility region of Fe3O4-TiO2-SiO2 ternary system. The glass-ceramics in the Fe3O4-TiO2-SiO2 system has a phase-separation texture, which consisted of Fe3O4-TiO2-rich and SiO2-rich phases, and shows ferromagnetic properties. The internal textures of wire samples were needle-like structure parallel to the direction of the elongation. The

T. Abe; T. Kishi; A. Yasumori

2009-01-01

347

Magnetic properties of glass ceramic wire in Fe3O4-TiO2-SiO2 system  

NASA Astrophysics Data System (ADS)

A glassy composite magnetic wire was prepared by elongation during quenching phase-separated melt in two-liquids stable immiscibility region of Fe3O4-TiO2-SiO2 ternary system. The glass-ceramics in the Fe3O4-TiO2-SiO2 system has a phase-separation texture, which consisted of Fe3O4-TiO2-rich and SiO2-rich phases, and shows ferromagnetic properties. The internal textures of wire samples were needle-like structure parallel to the direction of the elongation. The wire sample had larger saturated magnetization and lower coercive force than those of non-elongated bulk one.

Abe, T.; Kishi, T.; Yasumori, A.

2009-11-01

348

Superconducting wire  

Microsoft Academic Search

This invention consists of a method of producing superconducting wire by drawing a glass fiber with a melted powder of a superconducting wire inside the glass tube. After drawing, the glass fiber is heated to crystallize the superconducting compound. The diameter of the superconducting wires is controlled by the rate at which the glass fiber s are drawn from the

D. E. Day; J. J. Petrovic; F. D. Gac; C. S. Ray

1991-01-01

349

Wire Maze  

NSDL National Science Digital Library

Learners create an electrical-circuit maze out of wire, then try to pass a paperclip through the maze without touching the wire. If the paper clip touches the wire, it closes the circuit, causing a light to come on or a buzzer to sound. This activity requires a basic understanding of how to build an electrical circuit.

Institute, Worcester P.

2005-01-01

350

Superconducting wire  

DOEpatents

This invention consists of a method of producing superconducting wire by drawing a glass fiber with a melted powder of a superconducting wire inside the glass tube. After drawing, the glass fiber is heated to crystallize the superconducting compound. The diameter of the superconducting wires is controlled by the rate at which the glass fiber s are drawn from the glass tube.

Day, D.E.; Petrovic, J.J.; Gac, F.D.; Ray, C.S.

1991-03-05

351

A study of the parallel algorithm for large-scale DC simulation of nonlinear systems  

NASA Astrophysics Data System (ADS)

Newton-Raphson DC analysis of large-scale nonlinear circuits may be an extremely time consuming process even if sparse matrix techniques and bypassing of nonlinear models calculation are used. A slight decrease in the time required for this task may be enabled on multi-core, multithread computers if the calculation of the mathematical models for the nonlinear elements as well as the stamp management of the sparse matrix entries are managed through concurrent processes. This numerical complexity can be further reduced via the circuit decomposition and parallel solution of blocks taking as a departure point the BBD matrix structure. This block-parallel approach may give a considerable profit though it is strongly dependent on the system topology and, of course, on the processor type. This contribution presents the easy-parallelizable decomposition-based algorithm for DC simulation and provides a detailed study of its effectiveness.

Cortés Udave, Diego Ernesto; Ogrodzki, Jan; Gutiérrez de Anda, Miguel Angel

2012-05-01

352

Interplay of dc current and microwaves in the magnetotransport of two-dimensional electron systems  

NASA Astrophysics Data System (ADS)

We theoretically study magnetoresistance oscillations in two-dimensional electron systems in the presence of microwaves and a dc electric field. We obtain that the microwave-induced resistance oscillations and zero resistance states are dramatically affected by a dc electric field of increasing intensity. The interplay of both fields produces a plasma wave which oscillates at the frequency of microwaves but with a phase difference of ? radians. This plasma wave interferes with the microwave-induced electronic motion changing gradually the resistance oscillations profile: maxima evolve to minima and vice versa. We introduced in our model anharmonicity corrections to magnetoresistance oscillations in order to explain the peculiar biased profile that experimental results present. The theoretical outcomes are in agreement with experimental evidence.

Iñarrea, Jesús

2009-11-01

353

Experiment of 200-meter superconducting DC cable system in Chubu University  

NASA Astrophysics Data System (ADS)

We designed and constructed the experimental device of 200-meter superconducting DC cable system in the beginning of 2010 and did the first experiment until March, 2010, and the second experiment has been done from August to October 2010. This experimental device is called CASER-2, and the main aim of the experiment is to demonstrate high performance of DC superconducting cable system for comparing the copper cable system. Thermal contraction and expansion during the thermal cycle are discussed in the paper because if the thermal stress of the HTS tape conductor is high, the critical current of the HTS tape is reduced. Therefore, it is the first priority to keep the system in high performance and safety. We also mentioned several experiments and ideas in the paper, such as the low heat leaks of the terminal cryostat and the cryogenic pipe, and the low circulation power, energy storage function of the cable system. In this paper, we present the experimental results of the CASER-2, and discuss and estimate the performance of the system and several ideas. These discussions include the specification of the future long cable system, and show the subjects to solve for the future system.

Yamaguchi, S.; Kawahara, T.; Hamabe, M.; Watanabe, H.; Ivanov, Yu.; Sun, J.; Iiyoshi, A.

2011-11-01

354

Research and Development of an Intelligent Temperature-Measuring System Based on 1Wire Bus  

Microsoft Academic Search

Through the research on stratum freeze construction, and based on monitoring the application environment of long-distance stratum freezing in coal-mine construction, temperature monitoring method of 1-wire bus was proposed. According to the 1-wire bus technology and theory, the characteristic of time signaling conveyance was analyzed, the 1-wire bus drive circuit controlled by SCM was designed, and a new generation of

Hongmei Xue

2008-01-01

355

Description of the control system design for the SSF PMAD DC testbed  

NASA Astrophysics Data System (ADS)

The Power Management and Distribution (PMAD) DC Testbed Control System for Space Station Freedom was developed using a top down approach based on classical control system and conventional terrestrial power utilities design techniques. The design methodology includes the development of a testbed operating concept. This operating concept describes the operation of the testbed under all possible scenarios. A unique set of operating states was identified and a description of each state, along with state transitions, was generated. Each state is represented by a unique set of attributes and constraints, and its description reflects the degree of system security within which the power system is operating. Using the testbed operating states description, a functional design for the control system was developed. This functional design consists of a functional outline, a text description, and a logical flowchart for all the major control system functions. Described here are the control system design techniques, various control system functions, and the status of the design and implementation.

Baez, Anastacio N.; Kimnach, Greg L.

356

A high resolution wire scanner beam profile monitor with a microprocessor data acquisition system  

SciTech Connect

A beam profile monitor has been constructed for the NBS-LANL Racetrack Microtron. The monitor consists of two perpendicular 30 ..mu..m diameter carbon wires that are driven through an electron beam by a pneumatic actuator. A long-lifetime, electroformed nickel bellows is used for the linear-motion vacuum feedthrough. Secondary emission current from the wires and a signal from a transducer measuring the position of the wires are simultaneously digitized by a microprocessor to yield beam current density profiles in two dimensions. The wire scanner is designed for use with both pulsed and cw beams.

Cutler, R.I.; Mohr, D.L.; Whittaker, J.K.; Yoder, N.R.

1983-08-01

357

Evaluation of CWMS (continuous-wave measurement system) single-wire dipole antenna  

SciTech Connect

The Numerical Electromagnetics Code (NEC) was used to model a ''single-wire horizontal dipole antenna'' used with the FCDNA continuous-wave measurement system (CWMS). Line drawings and construction information were supplied to LLNL staff by FCDNA and EGG personnel, and NEC models were developed accordingly. Data were obtained from NEC describing all components of the electric and magnetic fields at nine different field-strength measurement points, as well as the input impedance at the antenna feed-point. Thirteen frequencies were used in the model, ranging all the way from 10 kHz to 100 MHz. In addition, the antenna was examined in two configurations, with and without a coaxial transmission line which extended from the feed-point balun to ground level. 16 figs., 46 tabs.

Breakall, J.K.; Christman, A.M.

1987-11-30

358

Tunneling of Individual Two-Level Systems in Mesoscopic Bi Wires  

NASA Astrophysics Data System (ADS)

We report systematic experimental studies of single bistable defects in mesoscopic Bi wires(N.E. Zimmerman et al., PRL 67), 1322 (1991);B. Golding et al., PRL 68, 998 (1992). with lateral dimensions of 40 nm which are fabricated using electron-beam lithography. We measure the random telegraph-type conductance fluctuations due to the tunneling of the bistable defects that interact with the electronic reservoir. The transition rates of the two-level systems are calculated from the random telegraph signal at temperatures down to 50 mK and in magnetic fields up to 14 T. We shall describe new results on the coupling of the bistable defects with the electronic thermal reservoir and modulation of the defect tunneling rates by external fields.

Wu, Wenhao; Golding, B.

1997-03-01

359

Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets  

SciTech Connect

The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between the project start and that date a substantial shift in the MRI marketplace occurred, with rapid growth for systems at higher fields (1.5 T and above) and a consequent decline in the low field market (<1.0 T). While the project aim appeared technically attainable at that time, the conclusion was reached that the system and market economics do not warrant additional investment. The program was redirected to develop BSCCO 2212 multifilament wire development for high field superconducting magnets for NMR and other scientific research upon an agreement between DOE and Oxford Instruments, Superconducting Technology. The work t took place between September, 2004 and the project end in early 2006 was focused on 2212 multifilamentary wire. This report summarizes the technical achievements both in 2212 dip coated for an HTS MRI system and in BSCCO 2212 multifilamentary wire for high field magnets.

Kennth Marken

2006-08-11

360

Carrier frequency offset estimation for OFDM systems with time-varying DC Offset  

NASA Astrophysics Data System (ADS)

Orthogonal frequency division multiplexing (OFDM) systems with direct-conversion architecture suffer from both carrier frequency offset (CFO) and dc offset (DCO). In this paper, we study CFO estimation problem for OFDM systems with time-varying DCO (TV-DCO) caused by gain mode switch of low noise amplifier (LNA). Based on linear approximation of TV-DCO, a blind algorithm is proposed for CFO estimation by means of DCO compensation and power leakage minimization. Performance of the proposed algorithm is demonstrated by simulations.

Liu, Tao; Li, Hanzhang

2012-12-01

361

An accurate AC-Dc voltage transfer standard test system using the differential and the dual-channel method  

Microsoft Academic Search

In the Electrotechnical Laboratory (ETL) the accuracy of the AC-DC voltage transfer difference was improved for the voltage range of 1-20 V in the frequency range from 10 Hz to 100 kHz. At the same time, the AC-Dc transfer standards and the measurement system which is used in the Japan Electric Meter Inspection Corporation (JEMIC) were also improved. The system

K. Takahashi; H. Sasaki; M. Klonz; T. Endo

1993-01-01

362

Dynamics of a dual-spinning satellite with extensive wire antenna systems  

Microsoft Academic Search

The GEOTAIL satellite, designed and developed by the Institute of Space and Astronautical Science of Japan will be launched by the NASA's Delta II rocket in July 1992. The dual-spinning satellite, equipped with two pairs of wire antennas of 50 m in length, will contribute to deeper understanding of fundamental magnetospheric processes. The high degree of flexibility of the wire

Yasuhiro Morita; Motoki Hinada; Yoshihiko Takemoto

1991-01-01

363

Wiring for the secure storage module for the Plutonium Protection System  

Microsoft Academic Search

The wiring for the SSM is divided into two major subsystems: the logic subsystem and the power subsystem. The logic subsystem uses flat ribbon cables and printed wiring cards for low-level signal distribution. Its primary purpose is to provide communications from the Container Modules (CMs) directly to the microcomputer in the SSM Controller. The power subsystem uses conventional cables and

Arlowe

1979-01-01

364

Wiring for the Secure Storage Module for the Plutonium Protection System.  

National Technical Information Service (NTIS)

The wiring for the SSM is divided into two major subsystems: the logic subsystem and the power subsystem. The logic subsystem uses flat ribbon cables and printed wiring cards for low-level signal distribution. Its primary purpose is to provide communicati...

H. D. Arlowe

1979-01-01

365

THE BRIDGE: A COMPACT, UNOBTRUSIVE SYSTEM TO MEASURE TRELLIS WIRE TENSION TO ESTIMATE VINEYARD YIELDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

An automated method of estimating crop mass (yield) in grapevines is based on measuring the increase in tension in the support wire of the trellis. To implement this approach in commercial vineyards, confounding issues must be accounted for, including environmental influences on the wire, sensitivit...

366

A Guide to the Electromagnetic Pulse Hardening of Open-Wire Systems to the Exoatmospheric Army Threat Environment.  

National Technical Information Service (NTIS)

A theoretical study of EMP response is presented for a family of open-wire systems. The goal is to provide the designer with an understanding of the performance of a number of hardening techniques. The hardening designs encompass both linear filter networ...

M. J. Vrabel R. A. Yescavage L. D. Dillingham

1980-01-01

367

Start-Up Built-in Test for the Discus Fault Tolerant, Fly-by-Wire Computer System.  

National Technical Information Service (NTIS)

The work carried out to implement built-in test on the Digital Self-healing Control for Upgraded Safety (DISCOUS) system is presented. The use of built-in test procedures are discussed as they apply to the DISCUS fault tolerant, fly-by-wire computer syste...

R. Sudduth

1990-01-01

368

Anticrossing of spin-split subbands in quasi-one-dimensional wires.  

PubMed

In quantum Hall systems, both anticrossings and magnetic phase transitions can occur when opposite-spin Landau levels coincide. Our results indicate that both processes are also possible in quasi-1D quantum wires in an in-plane B field, Bparallel. Crossings of opposite-spin 1D subbands resemble magnetic phase transitions at zero dc source-drain bias, but display anticrossings at high dc bias. Our data also imply that the well-known 0.7 structure may evolve into a spin-hybridized state in finite dc bias. PMID:18643444

Graham, A C; Simmons, M Y; Ritchie, D A; Pepper, M

2008-06-06

369

A new STATCOM topology to compensate loads containing AC and DC components  

Microsoft Academic Search

The paper proposes a new topology of STATCOM that is capable of supplying AC and DC loads in 3-phase 4-wire distribution systems. In this, the authors utilize the method of instantaneous symmetrical components to extract the compensator reference currents that are then tracked in a hysteresis band current control mode. A suitable state space model of the STATCOM is derived.

M. K. Mishra; Arindam Ghosh; A. Joshi

2000-01-01

370

A COAXIAL TE011 CAVITY AND A SYSTEM TO MEASURE DC AND RF PROPERTIES OF SUPERCONDUCTORS  

SciTech Connect

A coaxial niobium cavity has been designed and built where the center conductor consists of a removable sample. In addition, a system to measure properties such as magnetization, penetration depth, critical temperature and thermal conductivity on the same cylindrical sample has been designed and built. The purpose of this effort is to investigate possible correlations between DC and RF properties of superconductors. In this contribution, the design of the various components is discussed and the test results on a niobium sample obtained so far are presented.

Gianluigi Ciovati; Peter Kneisel; Ganapati Myneni; Larry Turlington; Gary Slack; Michael Morrone; William Clemens; Richard Bundy; Thomas Elliott; Jayanta Mondal

2008-01-23

371

[Evaluation of a DC pulsed magnetic tracking system in neurosurgical navigation: technique, accuracies, and influencing factors].  

PubMed

Navigation systems are useful instruments in cranial neurosurgery. For specification of position, so-called sensor-based navigation techniques use: (a) a signal emitter that generates a defined electromagnetic field in the area of the operation site; and (b) small sensors that detect the position of various operating instruments in the electromagnetic field. For a long time, owing to a lack of clinical data and long-term studies, electromagnetic systems have been regarded as error-prone and imprecise. With the development of a pulsed direct current (DC) technique, precision levels can now be reached that are comparable with those of established optical and mechanical measuring procedures. However, it must be noted that the influence on the measuring accuracy within the operating field increases with increasing susceptibility of the various metals used in the operating theatre (titaniumDC pulsed magnetic tracking system were investigated in more than 200 cases. PMID:17561783

Suess, Olaf; Suess, Silke; Mularski, Sven; Kühn, Björn; Picht, Thomas; Schönherr, Sven; Kombos, Theodoros

2007-06-01

372

The failure of DFT computations for a stepped-substrate-supported monatomic highly-correlated wire system  

NASA Astrophysics Data System (ADS)

The ab-initio method, density functional theory (DFT), has been immensely successful in its ability to predict physical properties of condensed matter systems. In particular, DFT calculations have proven to be quantitatively accurate in predicting structural properties in a wide range of materials and qualitative failures are rare. Here, however, we show that DFT can fail qualitatively to correctly predict the dimerized structural phase for a recently reported experimentally realized monatomic Co wire system that is self-assembled on a vicinal, i.e. stepped, Cu(111) substrate [1]. We attribute this failure to DFT's over-prediction of hybridization of the Co wire with the underlying Cu substrate. We demonstrate that this over-hybridization leads to weakening of the magnetic coupling along the wire, which is responsible for dimerization, while increasing the stiffness of the wire due to strengthening of the non-magnetic elastic term. Additionally, we show that accounting for local interactions via DFT+U also fails at predicting the correct structural phase. [1] N. Zaki et al, arXiv:1208.0612 (2012)

Zaki, Nader; Osgood, Richard M.; Millis, Andrew J.; Marianetti, Chris A.

2013-03-01

373

Impact of quasi-dc currents on three-phase distribution transformer installations. Power Systems Technology Program  

SciTech Connect

This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary (load) side of the step-down transformer the harmonic content at the secondary side is quite high and saturation occurs with a relatively low level of dc injection; however, the reactive power demand is significantly lower. These tests produced no apparent damage to the transformers. Transformer damage is dependent on the duration of the dc excitation, the level of the excitation, and on thermal characteristics of the transfer. The transformer response time is found to be much shorter than seen in power transformer tests at lower dc injection levels. This shorter response time suggests that the response time is strongly dependent on the injected current levels, and that higher levels of dc injection for shorter durations could produce very high reactive power demands and harmonic distortion within a few tenths of a second. The added reactive power load could result in the blowing of fuses on the primary side of the transformer for even moderate dc injection levels, and neutral currents are quite large under even low-level dc injection. This ``smoking neutral`` results in high-level harmonic injection into equipment via the neutral and in possible equipment failure.

McConnell, B.W.; Barnes, P.R. [Oak Ridge National Lab., TN (United States); Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Schafer, D.A. [Mission Research Corp., Albuquerque, NM (United States)

1992-06-01

374

Photovoltaic-Battery-Powered DC Bus System for Common Portable Electronic Devices  

Microsoft Academic Search

Renewable energy sources based on photovoltaic (PV) along with battery-based energy storage necessitate power conditioning to meet load requirements and\\/or be connected to the electrical grid. The power conditioning is achieved via a dc-dc converter and a DC-AC inverter stages to produce the desired AC source. This is also the case even when the load is of dc type, such

Dylan Dah-Chuan Lu; Vassilios G. Agelidis

2009-01-01

375

Photovoltaic-battery powered DC Bus system for common portable electronic devices  

Microsoft Academic Search

Renewable energy sources based on photovoltaic along with battery-based energy storage necessitate power conditioning to meet load requirements and\\/or be connected to the electrical grid. The power conditioning is achieved via a DC-DC converter and a DC-AC inverter stages to produce the desired AC source. This is also the case even when the load is of DC type such as

Dylan Dah-Chuan Lu; Vassilios G. Agelidis

2008-01-01

376

DC source assemblies  

DOEpatents

Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

Campbell, Jeremy B; Newson, Steve

2013-02-26

377

Study of Wire Rope Systems for Seismic Protection of Equipment in Buildings.  

National Technical Information Service (NTIS)

Wire rope isolators have found numerous applications in the shock and vibration isolation of military hardware and industrial machinery. In the study, the usefulness of these devices for the seismic protection of equipment in buildings is investigated. In...

A. M. Reinhorn G. F. Demetriades M. C. Constantinou

1992-01-01

378

Development of Active Catheter,Active Guide Wire and Micro Sensor Systems  

PubMed Central

Summary Active catheters and active guide wires which move like a snake have been developed for catheter-based minimally invasive diagnosis and therapy. Communication and control IC chips in the active catheter reduce the number of lead wires for control. The active catheter can be not only bent but also torsioned and extended. An ultra minature fiber-optic pressure sensor; a forward-looking ultrasonic probe and a magnetic position and orientation sensor have been developed for catheters and guide wires. These moving mechanisms and several sensors which are fitted near the tip of the catheter and the guide wire will provide detailed information near the tip and enable delicate and effective catheter intervention.

Haga, Y.; Mineta, T.; Totsu, K.; Makishi, W.; Esashi, M.

2001-01-01

379

Field Trial on a Rack-mounted DC Power Supply System with 80-Ah Lithium-ion Batteries  

NASA Astrophysics Data System (ADS)

Using an industrial lithium-ion battery that has higher energy density than conventional valve-regulated lead-acid batteries, a rack-mounted DC-power-supply system was assembled and tested at a base transceiver station (BTS) offering actual services. A nominal output voltage and maximum output current of the system is 53.5V and 20A, respectively. An 80-Ah lithium-ion battery composed of 13 cells connected in series was applied in the system and maintained in a floating charge method. The DC-power-supply system was installed in a 19-inch power rack in the telecommunications equipment box at BTS. The characteristics of the 80Ah lithium-ion battery, specifications of the DC-power-supply system and field-test results were shown in this paper.

Matsushima, Toshio

380

A high resolution wire scanner beam profile monitor with a microprocessor data acquisition system  

Microsoft Academic Search

A beam profile monitor has been constructed for the NBS-LANL Racetrack Microtron. The monitor consists of two perpendicular 30 ..mu..m diameter carbon wires that are driven through an electron beam by a pneumatic actuator. A long-lifetime, electroformed nickel bellows is used for the linear-motion vacuum feedthrough. Secondary emission current from the wires and a signal from a transducer measuring the

R. I. Cutler; D. L. Mohr; J. K. Whittaker; N. R. Yodert

1983-01-01

381

DC brush-less servo motor drive systems using automatic learning control-based auto gain parameter tuning scheme  

Microsoft Academic Search

In this paper, the authors describe an advanced control method of system parameter auto-tuning implementation for a DC brushless motor drive system using fuzzy reasoning logic with an automatic learning control function. This method includes three features: (i) it is not necessary to input some kind of fuzzy rule to the servo system before starting autotuning operation; thus fuzzy rules

Kenji Inoue; Junji Yoshitsugu; Shin Shirogane; P. Boyagoda; Mutsuo Nakaoka

1997-01-01

382

Mission profile based optimization of a synchronous-buck DC-DC converter for a Wearable Power System  

Microsoft Academic Search

A Wearable Power System (WPS) is a portable fuel-to-electrical energy converter that is carried on the body and is able to supply an average of 20 W for 4 days and has a total weight of less than 4 kg. Due to limited total weight of the system, each system part must have the highest efficiency to weight ratio. This

M. Vasic; S. D. Round; J. Biela; J. W. Kolar

2009-01-01

383

Maximum power point tracking by incremental conductance method for photovoltaic systems with phase shifted full-bridge dc-dc converter  

Microsoft Academic Search

th 3 Abstract- Because of sunshine variation, output power of photo­ voltaic (PV) array can be fluctuated. In order to obtain fully uti­ lization from the PV array, an algorithm of maximum power point tracking (MPPT) functions with a high efficiency of dc-dc converter is necessary. This paper presents a phase-shifted full­ bridge dc-to-dc converter which is appropriate for PV

Phattara Suwannatrai; Pisit Liutanakul; Pongpit Wipasuramonton

2011-01-01

384

High-efficiency standby forward converter integrated with DC\\/DC Phase-Shift Full Bridge converter for server power supply system  

Microsoft Academic Search

This paper presents high-efficiency standby forward converter integrated with the DC\\/DC Phase-Shift Full Bridge (PSFB) converter. By sharing one leg of DC\\/DC PSFB converter, the proposed converter features low- voltage stress, no snubber and zero-voltage switching (ZVS) over the entire load range. Thus, the proposed converter has high-efficiency, especially under half load condition. Furthermore, by using forward-type transformer instead of

Shin-Young Cho; Jae-Kook Kim; Il-Woon Lee; Moon-Young Kim; Gun-Woo Moon

2011-01-01

385

A new generic family of saturable reactor-assisted soft-switching PWM DC-DC converters for high-power density distributed power systems  

Microsoft Academic Search

A generic family of high power density DC-DC power converter topologies with high-frequency AC link and without transformer isolation link is described. A saturable reactor assisted (SRA) soft switching mode constant frequency pulse width modulation (PWM) technique efficiently operates at a zero voltage switching transition scheme. This kind of quasi-trapezoidal wave mode PWM DC-DC power converter incorporates a small saturable

M. Nakaoka; M. Michihira; S. Hamada; Y. Murakami

1992-01-01

386

Point of collapse and continuation methods for large ac/dc systems  

SciTech Connect

This paper describes the implementation of both Point of Collapse (PoC) methods and continuation methods for the computation of voltage collapse points (saddle-node bifurcations) in large ac/dc systems. A comparison of the performance of these methods is presented for real systems of up to 2,158 buses. The paper discusses computational details of the implementation of the PoC and continuation methods, and the unique challenges encountered due to the presence of high voltage direct current (HVDC) transmission, area interchange power control regulating transformers, and voltage and reactive power limits. The characteristics of a robust PoC power flow program are presented, and its application to detection and solution of voltage stability problems is demonstrated.

Canizares, C.A. (Escuela Politecnica Nacional, Quito (Ecuador)); Alvarado, F.L. (Univ. of Wisconsin, Madison, WI (United States))

1993-02-01

387

DC simulator of large-scale nonlinear systems for parallel processors  

NASA Astrophysics Data System (ADS)

In this paper it is shown how the idea of the BBD decomposition of large-scale nonlinear systems can be implemented in a parallel DC circuit simulation algorithm. Usually, the BBD nonlinear circuits decomposition was used together with the multi-level Newton-Raphson iterative process. We propose the simulation consisting in the circuit decomposition and the process parallelization on the single level only. This block-parallel approach may give a considerable profit in simulation time though it is strongly dependent on the system topology and, of course, on the processor type. The paper presents the architecture of the decomposition-based algorithm, explains details of its implementation, including two steps of the one level bypassing techniques and discusses a construction of the dedicated benchmarks for this simulation software.

Cortés Udave, Diego Ernesto; Ogrodzki, Jan; Gutiérrez de Anda, Miguel Angel

2012-05-01

388

A Control Method for Regulating the DC Link Voltage of a Self-Commutated BTB System  

NASA Astrophysics Data System (ADS)

A self-commutated BTB(Back-To-Back) system for the purpose of achieving power flow control and/or frequency change in transmission systems has attractive features of reliable and continuous operations even under power fault conditions. However, an overvoltage appearing across the dc link during the fault conditions should be suppressed as small as possible because it does affect the voltage ratings of power devices. This paper proposes a new control method for effectively suppressing the overvoltage under power fault conditions. This method based on a combination of feedback and feedforward controls is characterized by compensation of power flow imbalance between two power converters. The validity of both the proposed method and the developed theory is confirmed by computer simulation.

Hagiwara, Makoto; Akagi, Hirofumi

389

Spatiotemporal patterns in a dc semiconductor-gas-discharge system: Stability analysis and full numerical solutions  

NASA Astrophysics Data System (ADS)

A system very similar to a dielectric barrier discharge, but with a simple stationary dc voltage, can be realized by sandwiching a gas discharge and a high-ohmic semiconductor layer between two planar electrodes. In experiments this system forms spatiotemporal and temporal patterns spontaneously, quite similarly to, e.g., Rayleigh-Bénard convection. Here it is modeled with a simple discharge model with space charge effects, and the semiconductor is approximated as a linear conductor. In previous work, this model has reproduced the phase transition from homogeneous stationary to homogeneous oscillating states semiquantitatively. In the present work, the formation of spatial patterns is investigated through linear stability analysis and through numerical simulations of the initial value problem; the methods agree well. They show the onset of spatiotemporal patterns for high semiconductor resistance. The parameter dependence of temporal or spatiotemporal pattern formation is discussed in detail.

Rafatov, Ismail R.; Šija?i?, Danijela D.; Ebert, Ute

2007-09-01

390

Power management strategies in a local DC Power Distribution System of More Electric Aircraft with the help of hybrid storage and dissipation systems  

Microsoft Academic Search

The local DC Power Distribution System of More Electric Aircraft is one of the cores of the electric power transmission. Because of some unidirectional devices (diode bridge and anti-run-back diodes), the system is not totally reversible. Some storage and dissipation systems are necessary to store or\\/and dissipate the returned energy to maintain the DC bus voltage. Power management strategies are

H. Zhang; H. Fakham; C. Saudemont; B. Robyns

2009-01-01

391

Efficient Design in a DC to DC Converter Unit.  

National Technical Information Service (NTIS)

Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is n...

F. R. Williams G. V. Schmitz J. E. Bruemmer

2002-01-01

392

Working with Systems and Thinking Systemically--Disentangling the Crossed Wires  

ERIC Educational Resources Information Center

|This article explores two separate traditions that educational psychologists (EPs) in the UK have for working with systems. One of these is "systems work" with organisations such as schools. The other is "systemic thinking" for working with families. Over the years these two traditions, systems work and systemic thinking, have become crossed and…

Fox, Mark

2009-01-01

393

A study on DC hybrid three-phase fault current limiting interrupter for a power distribution system  

NASA Astrophysics Data System (ADS)

For the purpose of protecting electric power system, many researches and developments of fault current limiters are being performed. The authors studied a dc hybrid three-phase fault current limiting interrupter (FCLI) composed of a superconducting reactor and an S/N transition element, connected in series each other. The dc hybrid type fault current limiting interrupter can limit a fault current by means of the inductance of high temperature superconducting (HTS) coil together with the normal transition of HTS bulk material (HTSB). In the case of an accident, the normal transition of the bulk material can be accelerated by the magnetic field of the HTS coil. In this paper, the dc hybrid type fault current limiting interrupter for 5.5 km long 6.6 kV 600 A power distribution system is analyzed, and performances of fault current limitation and interruption are confirmed. Moreover, a reclosing operation is discussed for this power distribution system.

Shao, Hongtian; Satoh, Tomoyuki; Yamaguchi, Mitsugi; Fukui, Satoshi; Ogawa, Jun; Satoh, Takao; Ishikawa, Hiroyuki

2005-10-01

394

Networks of quantum wire junctions: A system with quantized integer Hall resistance without vanishing longitudinal resistivity  

NASA Astrophysics Data System (ADS)

We consider a honeycomb network built of quantum wires, with each node of the network having a Y junction of three wires with a ring through which flux can be inserted. The junctions are the basic circuit elements for the network, and they are characterized by 3×3 conductance tensors. The low energy stable fixed point tensor conductances result from quantum effects, and are determined by the strength of the interactions in each wire and the magnetic flux through the ring. We consider the limit where there is decoherence in the wires between any two nodes, and study the array as a network of classical three-lead circuit elements whose characteristic conductance tensors are determined by the quantum fixed point. We show that this network has some remarkable transport properties in a range of interaction parameters: It has a Hall resistance quantized at Rxy=h/e2, although the longitudinal resistivity is nonvanishing. We show that these results are robust against disorder, in this case nonhomogeneous interaction parameters g for the different wires in the network.

Medina, Jaime; Green, Dmitry; Chamon, Claudio

2013-01-01

395

Dissipation-driven phase transitions in superconducting wires  

NASA Astrophysics Data System (ADS)

Narrow superconducting wires with diameter d?0 (where ?0 is the bulk superconducting coherence length) are quasi-1D systems in which fluctuations of the order parameter strongly affect low-temperature properties. Indeed, fluctuations cause the magnitude of the order parameter to temporarily vanish at some point along the wire, allowing its phase to slip by 2?, and to produce finite resistivity for all temperatures below Tc. In this work, we show that a weak coupling to a diffusive metallic film reinforces superconductivity in the wire through a quench of phase fluctuations. We analyze the effective phase-only action of the system by a perturbative renormalization-group and a self-consistent variational approach to obtain the critical points and phases at T=0. We predict a quantum phase transition towards a superconducting phase with long-range order as a function of the wire stiffness and coupling to the metal. Finally we discuss implications for the DC resistivity of the wire.

Lobos, Alejandro; Iucci, Aníbal; Müller, Markus; Giamarchi, Thierry

2010-03-01

396

A Matrix– Source Converter With AC–DC Bidirectional Power Flow for an Integrated Starter Alternator System  

Microsoft Academic Search

This paper proposes a new converter using matrix converter theories and Z-source conversion concepts and illustrates its application for the integrated starter\\/alternator (ISA) system by a case study. The problem imposed by the traditional voltage source inverter to develop the relatively high dc voltage from the relatively low ac voltages of an ac machine in the ISA system has been

Keping You; M. F. Rahman

2009-01-01

397

On the Feasibility of the Brushless DC (BLDC) Motor and Controller for 42V Automotive Cooling Fan System  

Microsoft Academic Search

The electrical power demand in automobiles is increasing steadily every year due to addition of new electrical systems that enhances passenger comfort and safety. The present in vehicle 14 V DC power system is being pushed to the maximum limits to meet the high power loads. In the mean time, the 42 V power network(\\

Jun-Hyuk Choi; In-Sung Jung; Jin Hur; Ha-Gyeong Sung; Byoung-Kuk Lee

2007-01-01

398

Analysis and Design of a Photovoltaic System DC Connected to the Utility With a Power Factor Corrector  

Microsoft Academic Search

This paper presents a photovoltaic (PV) system parallel connected to an electric power grid with a power factor corrector (PFC) for supplying the DC loads. The operation principles and design considerations for the presented PV system are analyzed and discussed. The balanced distribution of the power flows between the utility and the PV panels is achieved automatically by regulating the

Yu-Kang Lo; Huang-Jen Chiu; Ting-Peng Lee; Irwan Purnama; Jian-Min Wang

2009-01-01

399

Dynamic and Vibration Analysis of a Multimotor DC Drive System With Elastic Shafts Driving a Tissue Paper Machine  

Microsoft Academic Search

In this paper, the influence of the stiffness and damping of real elastic shafts on the behavior of a multidrive system driving a tissue paper machine is investigated. The drive system consists of four DC motors, where two of them drive the Yankee drying cylinder and the other two drive the presses section. Six-pulse thyristor bridge power converters that are

Costas A. Michael; Athanasios N. Safacas

2007-01-01

400

Dc arc models and incident energy calculations  

Microsoft Academic Search

There are many industrial applications of dc power systems, but only a limited amount of scientific literature addresses the modeling of dc arcs. Since the early dc arc research focused on the arc as an illuminant, most of the early data was obtained from low current dc systems. More recent publications provide a better understanding of the high-current dc arc.

R. F. Ammerman; T. Gammon; P. K. Sen; J. P. Nelson

2009-01-01

401

Study of maximum power tracking techniques and control of DC\\/DC converters for photovoltaic power system  

Microsoft Academic Search

As the electric power supplied by solar arrays depends on the insolation, temperature and array voltage, it is necessary to control the operating points to draw the maximum power of the solar array. The object of this paper is to investigate the maximum power tracking algorithms which were often used to compare the tracking efficiencies for the system operating under

Chihchiang Hua; Chihming Shen

1998-01-01

402

A dc-coupled, high sensitivity bolometric detector system for the Infrared Telescope in Space  

NASA Astrophysics Data System (ADS)

We report the performance of an ac bridge readout system that has been developed for use on the Infrared Telescope in Space which is scheduled for launch in 1994. The ac bridge readout provides excellent dc stability enabling observing strategies well-suited to space-borne observations. The ability to modulate the optical signal slowly allows the use of new, highly sensitive, long time-constant bolometers. At 300 mK, the bolometers have an electrical noise equivalent power of 3 x 10 exp -17 W/sq rt Hz. The total noise of the differential signal, including amplifier noise, is less than 8 x 10 exp -17 W/sq rt Hz at frequencies as low as 35 mHz.

Devlin, M.; Lange, A. E.; Wilbanks, T.; Sato, S.

1993-04-01

403

UN Wire  

NSDL National Science Digital Library

Provided by the UN Foundation, UN Wire is a new "daily news summary covering the United Nations, global affairs and key international issues." Users interested in the UN or global affairs will find UN Wire an excellent resource for quick, concise accounts of the day's major stories. Each day, UN Wire covers issues such as UN Affairs; Health; Women, Children, and Population; Environment; Trade; Humanitarian Aid; Human Rights; and Peacekeeping. Typical entries include a few short paragraphs and direct links to the original news source and/or related resources. Free registration is required and users can subscribe for free daily email summaries of the headlines. UN Wire should be available for email delivery in complete form in the next few months.

1999-01-01

404

A Novel Integrated Magnetic Structure Based DC/DC Converter for Hybrid Battery/Ultracapacitor Energy Storage Systems  

SciTech Connect

This manuscript focuses on a novel actively controlled hybrid magnetic battery/ultracapacitor based energy storage system (ESS) for vehicular propulsion systems. A stand-alone battery system might not be sufficient to satisfy peak power demand and transient load variations in hybrid and plug-in hybrid electric vehicles (HEV, PHEV). Active battery/ultracapacitor hybrid ESS provides a better solution in terms of efficient power management and control flexibility. Moreover, the voltage of the battery pack can be selected to be different than that of the ultracapacitor, which will result in flexibility of design as well as cost and size reduction of the battery pack. In addition, the ultracapacitor bank can supply or recapture a large burst of power and it can be used with high C-rates. Hence, the battery is not subjected to supply peak and sharp power variations, and the stress on the battery will be reduced and the battery lifetime would be increased. Utilizing ultracapacitor results in effective capturing of the braking energy, especially in sudden braking conditions.

Onar, Omer C [ORNL

2012-01-01

405

Lagrangian modeling of DC-DC buck-boost and flyback converters  

Microsoft Academic Search

In this paper, mathematical modeling of the DC-DC converters which are regarded as switched systems are examined. The Lagrangian formalism is used to derive the mathematical models of the DC-DC converters and the Euler Lagrange models of DC-DC Buck-Boost and Flyback converters are obtained using this Lagrangian formalism.

H. A. Yildiz; Leyla Gören-Sümer

2009-01-01

406

DC Voltage Control of the DC Micro-Grid for Super High Quality Electric Power Distribution  

Microsoft Academic Search

``DC Micro-grid'' is a novel power system using dc distribution in order to provide super high quality electric power. The power is distributed through dc distribution line and converted to required ac or dc voltages by converters placed near loads. The load side converters do not need transformers by choosing proper distributed dc voltage (±170V). The dc distribution line is

Hiroaki Kakigano; Yushi Miura; Toshifumi Ise; Ryohei Uchida

2007-01-01

407

Ionization fronts in planar dc discharge systems with high-ohmic electrode  

NASA Astrophysics Data System (ADS)

Electric breakdown and ionization fronts are considered theoretically in a sandwichlike dc discharge system consisting of two plane-parallel electrodes and a gaseous gap in between. The key system feature is a high-ohmic cathode opposite to an ordinary metal anode. Such systems have received much attention from experimental studies because they naturally support current patterns. Using adiabatic description of electrons and two-scale expansion we demonstrate that in the low-current Townsend mode the discharge is governed by a two-component reaction-diffusion system. The latter provides quantitative system description on the macroscopic time scale (i.e., much larger than the ion travel time). The breakdown appears as an instability of the uniform overvoltage state. A seed current fluctuation triggers a shocklike ionization front that propagates along the discharge plane with constant speed (typically ˜ 104 cm/s ). Depending on the cathode resistivity the front exhibits either monotonic or oscillatory behavior in space. Other breakdown features, such as damping transient oscillations of the global current, can also be found as solutions of the reaction-diffusion equations.

Amiranashvili, Sh.; Gurevich, S. V.; Purwins, H.-G.

2005-06-01

408

Stretching Wires  

NSDL National Science Digital Library

In this activity, learners determine the elastic and plastic properties of different types of metal wires. Learners discover that wires of the same gauge, but made of different metals, typically support different loads (masses) before going through the elastic to plastic transition. Learners also learn the difference between elastic deformation, which is recoverable after the load is removed, and plastic deformation, which is not recoverable. Note: one way to save time on this lab is to have different groups test different metals.

Urbana-Champaign, University O.

2013-01-04

409

Verification Testing of a UH-1 Wire Strike Protection System (WSPS).  

National Technical Information Service (NTIS)

In-flight wire strikes poses a serious threat to low-level helicopter operations. Under the sponsorship of Headquarters, US Army Aviation Research and Development Command (AVARADCOM) tests were conducted by ATL to determine the suitability for UH-1H helic...

L. T. Burrows

1982-01-01

410

A new filtering technique to eliminate decaying DC and harmonics for power system phasor estimation  

Microsoft Academic Search

During faults, the voltage and current signals available to the relay are affected by the decaying DC component and harmonics. To make proper decisions, most of the relaying algorithms require the fundamental frequency phasor information immune to decaying DC effect and harmonics. Conventional Fourier and LES phasor estimation algorithms are affected by the presence of decaying-exponential transient in the fault

Vinayagam Balamourougan; T. S. Sidhu

2006-01-01

411

Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS  

NASA Astrophysics Data System (ADS)

The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test.In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

2012-08-01

412

Foundational model of structural connectivity in the nervous system with a schema for wiring diagrams, connectome, and basic plan architecture.  

PubMed

The nervous system is a biological computer integrating the body's reflex and voluntary environmental interactions (behavior) with a relatively constant internal state (homeostasis)-- promoting survival of the individual and species. The wiring diagram of the nervous system's structural connectivity provides an obligatory foundational model for understanding functional localization at molecular, cellular, systems, and behavioral organization levels. This paper provides a high-level, downwardly extendible, conceptual framework--like a compass and map--for describing and exploring in neuroinformatics systems (such as our Brain Architecture Knowledge Management System) the structural architecture of the nervous system's basic wiring diagram. For this, the Foundational Model of Connectivity's universe of discourse is the structural architecture of nervous system connectivity in all animals at all resolutions, and the model includes two key elements--a set of basic principles and an internally consistent set of concepts (defined vocabulary of standard terms)--arranged in an explicitly defined schema (set of relationships between concepts) allowing automatic inferences. In addition, rules and procedures for creating and modifying the foundational model are considered. Controlled vocabularies with broad community support typically are managed by standing committees of experts that create and refine boundary conditions, and a set of rules that are available on the Web. PMID:21078980

Swanson, Larry W; Bota, Mihail

2010-11-15

413

Foundational model of structural connectivity in the nervous system with a schema for wiring diagrams, connectome, and basic plan architecture  

PubMed Central

The nervous system is a biological computer integrating the body's reflex and voluntary environmental interactions (behavior) with a relatively constant internal state (homeostasis)—promoting survival of the individual and species. The wiring diagram of the nervous system's structural connectivity provides an obligatory foundational model for understanding functional localization at molecular, cellular, systems, and behavioral organization levels. This paper provides a high-level, downwardly extendible, conceptual framework—like a compass and map—for describing and exploring in neuroinformatics systems (such as our Brain Architecture Knowledge Management System) the structural architecture of the nervous system's basic wiring diagram. For this, the Foundational Model of Connectivity's universe of discourse is the structural architecture of nervous system connectivity in all animals at all resolutions, and the model includes two key elements—a set of basic principles and an internally consistent set of concepts (defined vocabulary of standard terms)—arranged in an explicitly defined schema (set of relationships between concepts) allowing automatic inferences. In addition, rules and procedures for creating and modifying the foundational model are considered. Controlled vocabularies with broad community support typically are managed by standing committees of experts that create and refine boundary conditions, and a set of rules that are available on the Web.

Swanson, Larry W.; Bota, Mihail

2010-01-01

414

Location of DC Line Faults in Conventional HVDC Systems With Segments of Cables and Overhead Lines Using Terminal Measurements  

Microsoft Academic Search

This paper presents a novel algorithm to determine the location of dc line faults in an HVDC system with a mixed transmission media consisting of overhead lines and cables, using only the measurements taken at the rectifier and inverter ends of the composite transmission line. The algorithm relies on the traveling-wave principle, and requires the fault-generated surge arrival times at

O. M. K. Kasun Nanayakkara; Athula D. Rajapakse; Randy Wachal

2012-01-01

415

Auto-Calibrating DC Link Current Sensing Technique for Transformerless, Grid Connected, H-Bridge Inverter Systems  

Microsoft Academic Search

Power electronic inverters are commonly used for the interfacing of distributed generation systems to the electrical power network. These electronic inverters operate in a current controlled mode to inject unity power factor sinusoidal current into the network. To prevent possible dc current injection, a mains frequency isolation transformer is often employed at the inverter output. This isolation transformer is a

Matthew Armstrong; David. J. Atkinson; C. Mark Johnson; T. D. Abeyasekera

2006-01-01

416

A new approach to dynamic analysis of ac networks incorporating detailed modeling of dc systems. Part II  

SciTech Connect

A new digital simulation concept which combines the detailed capability of the Electro-Magnetic Transients Program (EMTP) with the large system dynamic capability of a transient stability program (TSP) is applied to the study of interaction of a dc system with weak ac systems. The interface locations between the 2 simulations are extended to strategic points within the ac network. It is believed that greater predictability and authenticity of the response to disturbances have been achieved than hitherto.

Adapa, R. (Systems Engineering Dept., McGraw-Edison Power Systems, Cooper Industries, Inc., Canonsburg, PA (US)); Reeve, J. (Electrical Engineering Dept., Univ. of Waterloo, Waterloo, Ontario N2L 3G1 (CA))

1988-10-01

417

Optimization of a novel DC-link current modulated interface with 3-phase utility systems to minimize line current harmonics  

Microsoft Academic Search

A novel three-phase utility interface is discussed. The interface draws near-sinusoidal currents from the utility and provides a regulated DC output voltage. The performance of the system is optimized. Simulation results for a three-phase, 208 V (line-to-line), 3 kW system are presented. The sensitivity of the interface to unbalances in various system parameters is examined. Simulation results indicate that a

M. Rastogi; R. Naik; N. Mohan

1992-01-01

418

Optimizing design for low voltage DC-DC converters  

Microsoft Academic Search

Emerging portable battery-operated systems demand compact, high efficiency, low-voltage and low-power DC-DC converters to maximize system run-time. A hybrid control strategy is used to achieve high efficiency and to select reasonable passive elements over a wide load range. The purpose of this paper is to study design optimization for LV DC-DC power converters. In the paper, a hybrid-controlled buck converter

Xunwei Zhou; Thomas G. Wang; Fred C. Lee

1997-01-01

419

DC Electric Field Measurement by the Double Probe System Aboard Geotail and its Simulation  

NASA Astrophysics Data System (ADS)

We summarize the characteristics of the DC electric field measurement by the double probe system, PANT and EFD-P, aboard Geotail. The accuracy and correction factors for the gain (effective length) and off-set, which depends on ambient plasma conditions, are provided. Accurate measurements of electric fields are essential for space plasma studies, for example, plasma convection, wave-particle interactions, violation of MHD approximation, etc. One typical measurement techniques is the 'Double Probe method', identical to that of a voltmeter: the potential difference between two top-hat probes [cf. Pedersen et al., 1984]. This method can measure electric fields passively and continuously in all plasma conditions. However, the accuracy of the measured electric field values is limited. The probe measurement is also subjected to the variable gain (effective length) of the probe antenna and the artificial offset of the measured values. Those depend on a) the disturbance from ambient plasma and b) the disturbance from the spacecraft and the probe itself. In this paper, we show the results of the characteristics of DC electric field measurement by the PANT probe and the EFD-P (Electric Field Detector - Probe technique) receiver aboard Geotail [Tsuruda et al., 1994], in order to evaluate the accuracy, gain, and offset controlled by ambient plasmas. We conclude that the Geotail electric field measurement by the double probe system has the accuracy 0.4 mV/m for Ex and 0.3 mV/m for Ey, after the correction of the gain and offset. In better conditions, accuracy of Ey is 0.2 mV/m. The potential accuracy would be better because those values are limited by the accuracy of the particle measurement especially in low density conditions. In practical use, the corrections by long-term variation and spacecraft potential are effective to refine the electric field data. The characteristics of long-term variation and the dependences on ambient plasma are not fully understood well, yet. Further works will be needed based on the calibrated LEP data after 1998. It will also cover the conditions rejected in this paper, i.e., low density regions, potential controlled period, electric field quasi-parallel to magnetic field, etc. The comparison with EFD-B (EFD - Beam technique) data will also be included in order to reject the ambiguity in particle observations. In addition, we are trying to establish the numerical model of the double probe system for the full-quantitative understanding of the effect of potential structure and photoelectron distributions. Those will be the basis for planned experiments, BepiColombo to Mercury, ERG to the inner magnetosphere, and the multi-spacecraft magnetospheric mission SCOPE.

Kasaba, Y.; Hayakawa, H.; Ishisaka, K.; Okada, T.; Matsuoka, A.; Mukai, T.; Okada, M.

2005-12-01

420

A new circuit design and control to reduce input harmonic current for a three-phase ac machine drive system having a very small dc-link capacitor  

Microsoft Academic Search

This paper presents a new circuit topology to meet the input harmonic current standard for an ac machine drive system which has a very small dc-link capacitor. The proposed circuit topology is based on a harmonic current injection method, and it keeps up size and cost competitiveness of an ac machine drive system having a very small dc-link capacitor. Also,

Hyunjae Yoo; Seung-Ki Sul

2010-01-01

421

Six-state, three-level, six-fold ferromagnetic wire system  

NASA Astrophysics Data System (ADS)

Six stable states at remanence were identified in iron wire samples of 6-fold spatial symmetry using micromagnetic simulations and the finite element method. Onion and domain-wall magnetic states were tailored by sample shape and guided by an applied magnetic field with a fixed in-plane direction. Different directions of externally applied magnetic fields revealed a tendency for stability or nonstability of the considered states.

Blachowicz, T.; Ehrmann, A.

2013-04-01

422

A fretting fatigue tester for steel wires and its measuring system  

Microsoft Academic Search

A self-made fretting fatigue tester for steel wire based on the computer-controlled electro-hydraulic servo fatigue testing machine is introduced in the paper. The working principle and experimental method are described. The signals of contact load, fretting tangential force and fretting amplitude are collected using force and displacement sensors. Synchronous acquisition and dynamic display of the signals of various parameters are

Dagang Wang; Xiaofan Jia; Dekun Zhang; Songquan Wang

2010-01-01

423

Grid-connected PV-wind-fuel cell hybrid system employing a supercapacitor bank as storage device to supply a critical DC load  

Microsoft Academic Search

In this work a grid-connected renewable energy system composed by a 1kW photovoltaic (PV) array and a 1 kW wind turbine (WT) is presented. The generated power from each renewable source is processed by independent dc-dc converters and provided to a common dc bus. Once batteries employment is not desired, a 1.2 kW fuel cell (FC) and a supercapacitor bank

Roberto Francisco Coelho; Lenon Schimtz; Denizar Cruz Martins

2011-01-01

424

Two-Degrees-of-Freedom Model Matching Control of Shift-by-Wire System with Emergency Mechanical Link  

NASA Astrophysics Data System (ADS)

A new shift-by-wire system having a stand-by mechanical link with a backlash has been proposed. The link directly connects the select lever and the manual lever of the automatic transmission in case of emergency. Thus it is necessary to keep the backlash free during normal operations without generating a force. The angles of the manual lever driven by an actuator should follow the angles of the select lever exactly and quickly. A two-degrees-of-freedom model matching control is developed to meet this requirement. It is shown that the backlash is kept to be free during range select operation.

Osamura, Kensuke; Kobayashi, Sinya; Nagano, Masaharu; Hirata, Mitsuo; Adachi, Shuichi

425

Flying wires at Fermilab  

SciTech Connect

Transverse beam profile measurement systems called ''Flying Wires'' have been installed and made operational in the Fermilab Main Ring and Tevatron accelerators. These devices are used routinely to measure the emittance of both protons and antiprotons throughout the fill process, and for emittance growth measurements during stores. In the Tevatron, the individual transverse profiles of six proton and six antiproton bunches are obtained simultaneously, with a single pass of the wire through the beam. Essential features of the hardware, software, and system operation are explained in the rest of the paper. 3 refs., 4 figs.

Gannon, J.; Crawford, C.; Finley, D.; Flora, R.; Groves, T.; MacPherson, M.

1989-03-01

426

Thermodynamics of a closed-cycle gas flow system for cooling a HTc DC-squid magnetometer  

Microsoft Academic Search

A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the interface between the SQUID unit and the cooler (a Leybold Heraeus RG 210).

P. J. van den Bosch; H. J. M. Ter Brake; G. C. van den Eijkel; J. P. Boelens; H. J. Holland; J. F. C. Verberne; H. Rogalla

1994-01-01

427

Thermodynamics of a closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer  

Microsoft Academic Search

A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the interface between the SQUID unit and the cooler (a Leybold Heraeus RG 210).

Bosch van den P. J; Brake ter H. J. M; Eijkel van den G. C; J. P. Boelens; H. J. Holland; J. F. C. Verberne; H. Rogalla

1994-01-01

428

A PM Brushless DC Starter\\/Generator System for a Series-Parallel 2x2 Hybrid Electric Vehicle  

Microsoft Academic Search

A higher power starter\\/generator system has been implemented for a hybrid electric vehicle using a 20-kW PM brushless DC (BLDC) machine. The PM BLDC machine, coupled to the 1.9 L diesel engine of the vehicle, generates the electrical power to charge the high-voltage energy storage system and to drive an induction machine connected to the rear wheels. It may also

S. M. N. Hasan; I. Husain; R. J. Veillette; J. E. Carletta

2007-01-01

429

A unity power factor resonant AC\\/DC converter for high-frequency space power distribution system  

Microsoft Academic Search

This paper presents analysis and design of a resonant AC\\/DC converter topology, suitable for use in an advanced single-phase, sine-wave voltage, high-frequency power distribution system of the type that was proposed for a 20 kHz space station primary electrical power distribution system. The converter comprises a transformer, a double-tuned resonant network comprising of series- and parallel-tuned branches, a controlled rectifier,

P. K. Jain; M. C. Tanju

1997-01-01

430

Modeling and simulation of DC transit system with VSI-fed induction motor driven train using PSB\\/MATLAB  

Microsoft Academic Search

This paper presents a comprehensive simulation model of DC transit system with VSI-fed induction motor driven trains created using Power System Blockset (PSB)\\/MATLAB software package. The substation rectifier, the accurate track, the VSI-fed induction motor train and a detailed traction load are included in the model. The objective of this model is to study the short circuits faults that happen

C. S. Chang; A. Khambadkone; Zhao Xu

2001-01-01

431

Multi-scale simulation of plasma generation and film deposition in a circular type DC magnetron sputtering system  

Microsoft Academic Search

We present a computational study on the plasma generation and film deposition in a circular type DC magnetron sputtering system. Design optimization of a large-area magnetron sputtering system needs a precise multi-scale simulation considering a target erosion by magnetron plasma, a macrofilm deposition by collisional transport, and a micro-deposition topography by collisionless transport. Our multi-scale simulation consists of particle-in-cell and

U. H. Kwon; S. H. Choi; Y. H. Park; W. J. Lee

2005-01-01

432

DC Machine  

NSDL National Science Digital Library

The effect of the commutator is to produce a fixed spatial distribution of current directions in the armature conductors (shown as blue & green circles) independent of shaft rotation. The field created by these currents (armature reaction) is vertically directed along the quadrature axis. The field established by the excitation of the stator poles is directed along the horizontal direct axis. This package presents computer models of electric machines based on the space vector formulation leading to the assessment of the dynamic performance of open- and closed-loopac and dc drive systems. The Simulink/Matlab implementation is adopted because of its inherent integration of vectorized system representations in block diagram form, of numerical analysis methods, of graphical portrayal of time evolutions of signals combined with the simple realization of the functionality of controllers and power electronic excitations. The development of Simulink models of drive assemblies is a relatively simple task consisting of combining input-output block representation of the various components making up the system; these blocks can readily be reused (utilizing standard copy-and-paste techniques) to modify the system components or the configuration of the system. This approach provides a powerful design tool because of the ease of observing the effects of parameters modifications and of differing system configurations and control strategies.

Riaz, Mahmoud

2012-08-29

433

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System  

SciTech Connect

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower part of the UHV range. Measured NEG pump speed is high at pressures above 5×10^?11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.

M.L. Stutzman; P. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; G.R. Myneni; M. Poelker

2007-05-01

434

No Wires.  

ERIC Educational Resources Information Center

|The University of California at Santa Cruz has completed a successful test of a wireless computer network that would enable students and professors to get on line from anywhere on campus. The network, linked by radio waves, could save millions of dollars in campus wiring costs and would better meet student and faculty information needs. (MSE)|

DeLoughry, Thomas J.

1995-01-01

435

47 CFR 68.215 - Installation of other than âfully protectedâ system premises wiring that serves more than four...  

Code of Federal Regulations, 2010 CFR

...shall be protected from adverse effects of weather and the environment...percent (measured linearly) of wiring run concealed in ducts, conduit or wall...telecommunications may require withdrawal of all wiring run concealed in ducts, conduit or...

2009-10-01

436

47 CFR 68.215 - Installation of other than âfully protectedâ system premises wiring that serves more than four...  

Code of Federal Regulations, 2010 CFR

...shall be protected from adverse effects of weather and the environment...percent (measured linearly) of wiring run concealed in ducts, conduit or wall...telecommunications may require withdrawal of all wiring run concealed in ducts, conduit or...

2010-10-01

437

Investigation of Helicopter Wire Strike Protection Concepts.  

National Technical Information Service (NTIS)

In-flight wire strikes pose a serious threat to low-level helicopter operations. Tests were conducted to determine the suitability for U. S. Army helicopter applications of the Canadian Wire Strike Protection System (WSPS), developed by Bristol Aerospace ...

L. T. Burrows

1980-01-01

438

49 CFR 236.838 - Wire, shunt.  

Code of Federal Regulations, 2011 CFR

...INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.838 Wire, shunt. A wire forming part of a shunt...

2011-10-01

439

46 CFR 111.60-11 - Wire.  

Code of Federal Regulations, 2012 CFR

...60-11 Section 111.60-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-11 Wire....

2012-10-01

440

The Isvr Constant Temperature Hot Wire Anemometer.  

National Technical Information Service (NTIS)

The principles of hot wire anemometer operation are summarized. The design, specifications, and applications for the constant temperature hot wire and hot film anemometer system are discussed. Information is provided on probe construction with selected re...

P. O. A. L. Davies J. Mason

1974-01-01

441

Locating Hidden Hazards in Electrical Wiring  

Microsoft Academic Search

Hazardous electrical wiring has been identified as an area of critical national and international concern. Faulty and improperly installed electrical wiring is a leading cause of fires in homes and commercial buildings. Wiring is also responsible for numerous problems in consumer product safety, vehicular safety\\/reliability, safety of nuclear facilities, reliability of power distribution systems, reliability of communication systems, and others.

Paul K. Kuhn

2006-01-01

442

Characteristics of the multiple-input DC-DC converter  

Microsoft Academic Search

In the zero-emission electric power generation system, a multiple-input DC-DC converter is useful to obtain the regulated output voltage from several input power sources such as a solar array, wind generator, fuel cell, and so forth. A new multiple-input DC-DC converter is proposed and analyzed. As a result, the static and dynamic characteristics are clarified theoretically, and the results are

Hirofumi Matsuo; Wenzhong Lin; Fujio Kurokawa; Tetsuro Shigemizu; Nobuya Watanabe

2004-01-01

443

Multiple-input full bridge dc\\/dc converter  

Microsoft Academic Search

In the renewable power system with two or more sources, the application of multiple-input converter (MIC) instead of several single-input converters can simplify the circuit and reduce the cost. A novel multiple-input full bridge dc\\/dc converter is proposed in this paper. Taking the two inputs as the example, the operation principles and characteristics of the double-input full bridge dc\\/dc converter

Dongsheng Yang; Xinbo Ruan; Yan Li; Fuxin Liu

2009-01-01

444

Fuzzy logic controller on DC\\/DC boost converter  

Microsoft Academic Search

This paper describes the design of a fuzzy logic controller using voltage output as feedback for significantly improving the dynamic performance of boost dc-dc converter by using MATLAB@Simulink software. The objective of this proposed methodology is to develop fuzzy logic controller on control boost dc-dc converter using MATLAB@Simulink software. The fuzzy logic controller has been implemented to the system by

N. F Nik Ismail; I. Musirin; R. Baharom; D. Johari

2010-01-01

445

Maximum power point tracking control and voltage regulation of a DC grid-tied wind energy conversion system based on a novel permanent magnet reluctance generator  

Microsoft Academic Search

This research paper aims to employ a new permanent magnet reluctance generator in a variable speed wind energy conversion system (WECS) of a grid-tied distributed generation application. The grid integration of WECS is achieved through cascaded dc-dc converters ensuring maximum power extraction from the wind energy while maintaining a constant output voltage at the grid side. The surplus power is

Kazmi Syed Muhammad Raza; Hiroki Goto; Hai-Jiao Guo; Osamu Ichinokura

2007-01-01

446

DC bus voltage build up and control in stand-alone wind energy conversion system using direct vector control of SCIM  

Microsoft Academic Search

This paper presents the start up and operation of a stand-alone wind energy conversion system (WECS) using a squirrel cage induction machine (SCIM). The proposed scheme obviates the use of either excitation capacitor or batteries in DC bus. The DC bus comprising of a combination of normal electrolytic capacitor and few super capacitors, is interfaced with the SCIM through a

Samir Hazra; Partha Sarathi Sensarma

2008-01-01

447

Plastic properties of crumpled wires  

Microsoft Academic Search

In this letter we study nonlinear irreversible mechanical properties of crumpled wires in a large interval of deformations. Power laws connecting the geometrical and mechanical variables for this kind of disordered system are examined. Critical exponents are obtained from experiments and from scaling arguments. The behaviour of crumpled wires and crumpled surfaces are compared.

M. A. F. Gomes; F. F. Lima; V. M. Oliveira

1991-01-01

448

Aircraft wiring program status report  

Microsoft Academic Search

In this Naval Air Warfare Center (NAWC) Aircraft Division status report, the general and wire and cable component activities, the systems engineering activities, the aircraft wiring lead maintenance activities, the NAVAIR\\/NASA interface activities, and the Base Realignment and Closure (BRAC) Commission recommendations are presented.

Rex Beach

1995-01-01

449

Aircraft wiring program status report  

NASA Astrophysics Data System (ADS)

In this Naval Air Warfare Center (NAWC) Aircraft Division status report, the general and wire and cable component activities, the systems engineering activities, the aircraft wiring lead maintenance activities, the NAVAIR/NASA interface activities, and the Base Realignment and Closure (BRAC) Commission recommendations are presented.

Beach, Rex

1995-11-01

450

Flying hot-wire anemometry  

Microsoft Academic Search

A flying hot-wire arrangement has been developed for the measurement of the velocity characteristics of the flow around airfoils, and particularly in regions where negative values of instantaneous velocity occur. The mechanism and signal processing system are described and appraised by comparing stationary and flying wire measurements obtained in the trailing edge region of a flap at an angle of

B. E. Thompson; J. H. Whitelaw

1984-01-01

451

Comparison of inelastic and quasielastic scattering effects on nonlinear electron transport in quantum wires  

NASA Astrophysics Data System (ADS)

When impurity and phonon scattering coexist, the Boltzmann equation has been solved accurately for nonlinear electron transport in a quantum wire. Based on the calculated nonequilibrium distribution of electrons in momentum space, the scattering effects on both the nondifferential (for a fixed dc field) and differential (for a fixed temperature) mobilities of electrons as functions of temperature and dc field have been demonstrated. The nondifferential mobility of electrons is switched from a linearly increasing function of temperature to a paraboliclike temperature dependence as the quantum wire is tuned from an impurity-dominated system to a phonon-dominated one, as described by Fang et al. [Phys. Rev. B 78, 205403 (2008)]. In addition, a maximum has been obtained in the dc field dependence of the differential mobility of electrons. The low-field differential mobility is dominated by the impurity scattering, whereas the high-field differential mobility is limited by the phonon scattering as described by Hauser et al. [Semicond. Sci. Technol. 9, 951 (1994)]. Once a quantum wire is dominated by quasielastic scattering, the peak of the momentum-space distribution function becomes sharpened and both tails of the equilibrium electron distribution centered at the Fermi edges are raised by the dc field after a redistribution of the electrons is fulfilled in a symmetric way in the low-field regime. If a quantum wire is dominated by inelastic scattering, on the other hand, the peak of the momentum-space distribution function is unchanged while both shoulders centered at the Fermi edges shift leftward correspondingly with increasing dc field through an asymmetric redistribution of the electrons even in low-field regime as described by Wirner et al. [Phys. Rev. Lett. 70, 2609 (1993)].

Huang, Danhong; Gumbs, Godfrey

2010-05-01

452

Three-Level Inverter-Based Shunt Active Power Filter in Three-Phase Three-Wire and Four-Wire Systems  

Microsoft Academic Search

This paper presents a direct current-space-vector control of an active power filter (APF) based on a three-level neutral-point-clamped (NPC) voltage-source inverter. The proposed method indirectly generates the compensation current reference by using an equivalent conductance of the fundamental component using APF's dc-link voltage control. The proposed control can selectively choose harmonic current components by real-time fast Fourier transform to generate

Oleg Vodyakho; Chris C. Mi

2009-01-01

453

Protection of Low-Voltage DC Microgrids  

Microsoft Academic Search

In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. The LV DC microgrid is used to interconnect distributed resources and sensitive electronic loads. When designing an LV DC microgrid protection system, knowledge from existing DC power systems can be used. However, in most cases, these systems use grid-connected rectifiers with current-limiting capability during DC faults. In

Daniel Salomonsson; Lennart Söder; Ambra Sannino

2009-01-01

454

Universality versus material dependence of fluctuation forces between metallic wires  

SciTech Connect

We calculate the Casimir interaction between two parallel wires and between a wire and a metal plate. The dielectric properties of the objects are described by the plasma, Drude, and perfect metal models. We find that at asymptotically large separation interactions involving plasma, wires and/or plates are independent of the material properties but depend on the dc conductivity {sigma} for Drude wires. Counterintuitively, at intermediate separations the interaction involving Drude wires can become independent of {sigma}. At smaller separations, we compute the interaction numerically and observe an approach to the proximity approximation.

Noruzifar, E. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Emig, T. [Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Universite Paris-Sud, 91405 Orsay (France); Zandi, R. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Universite Paris-Sud, 91405 Orsay (France)

2011-10-15

455

Universality versus material dependence of fluctuation forces between metallic wires  

NASA Astrophysics Data System (ADS)

We calculate the Casimir interaction between two parallel wires and between a wire and a metal plate. The dielectric properties of the objects are described by the plasma, Drude, and perfect metal models. We find that at asymptotically large separation interactions involving plasma, wires and/or plates are independent of the material properties but depend on the dc conductivity ? for Drude wires. Counterintuitively, at intermediate separations the interaction involving Drude wires can become independent of ?. At smaller separations, we compute the interaction numerically and observe an approach to the proximity approximation.

Noruzifar, E.; Emig, T.; Zandi, R.

2011-10-01

456

Wiring and Cabling  

NSDL National Science Digital Library

Created by Work-Ready Electronics, a project of the Advanced Technological Education program, this module introduces students to wiring and cabling principles, including transmission lines, computer network and wireless systems, and troubleshooting. The Knowledge Probes allow students to answer open-ended questions covering the content of the module, and the Learning Resources present activities, laboratories, and games to further solidify the material. The Notebook function allows visitors to take notes and review them at any time. This is an excellent resource for vocational electronics educators as a ready-made classroom introduction to wiring and cabling.

2008-12-08

457

Subsystem-interaction restraint in the two-stage DC distributed power systems with decoupling-controlled-integration structure  

Microsoft Academic Search

Subsystem interaction is an important issue in the two-stage dc distributed power system (DPS) featuring many individually regulated subsystems well designed in their standalone mode. This paper investigates not only the mechanism of realizing the subsystem-interaction restraint with the decoupling-controlled-integration (DI) structure, but also the improvement of DPS's small-signal stability and the regulated load converter's input impedance consequent on the

Xiaopeng Wang; Ruoping Yao; Fangquan Rao

2005-01-01

458

Influence of particles on AC and DC electrical performance of gas insulated systems at extra-high-voltage  

Microsoft Academic Search

High-voltage breakdown measurements were made in two similar particle contaminated coaxial test systems, one with AC and the other with DC voltages. Information is presented on the effects of particle size, shape, and material for both SF6and N2gases at pressures up to 15 atm in a plain coaxial gap and a coaxial gap including a post-type support spacer. Particle motion

C. M. Cooke; R. E. Wootton; A. H. Cookson

1977-01-01

459

Steady-State and Stability Analysis of an Analog-Type Phase-Locked Loop DC Motor Control System  

Microsoft Academic Search

A novel analog-type phase locked loop (PLL) control scheme for a separately excited dc motor is described. The steady-state analysis has been carried out to study the variation of phase angle difference between the reference and feedback signals, under no-load and load conditions. The effect of moment of inertia, amplifier gain, and differentiator time constant on stability of the system

K. Eapen; K. Venkatesan; S. C. Gupta

1980-01-01

460

Modeling, simulation, and control of an electromechanical aerofin control system with a PWM-controlled DC motor  

Microsoft Academic Search

A nonlinear model of an electromechanical actuator (EMA) system for aerofin control is presented. The EMA is realized with\\u000a a permanent magnet brush DC motor controlled by a constant current driver. In this paper we introduced a simulation model\\u000a that includes nonlinearities of the motor driver. A PID position controller was designed using the simulation model, although\\u000a it was impossible

M. R. Ristanovic; D. V. Lazic; I. Indjin

2008-01-01

461

Non-contact measurement of dc voltages using nonlinear elements  

NASA Astrophysics Data System (ADS)

In this work, it is shown that dc voltages may be measured via a capacitive interface, provided that the capacitance between the measurement system and the dc voltage source being measured is nonlinearized. This nonlinearization is achieved by the addition of a nonlinear capacitor in series with the coupling capacitance. Two types of nonlinear capacitor are used—multilayer ceramics and varicap diodes. Currently available multilayer ceramics have a larger value than desired but prove the concept, while the small capacitance of the varicap diode allows measurement on real wires. Results show that over a low voltage range (-8 V to +8 V), the voltage on a conductor can be measured if the coupling capacitance between source and electrode is larger than 20 pF, which equates to an electrode length of 5 cm when wire compliant with MIL-W-81044-22 is used. Detection is performed by momentarily applying a voltage at a node within the measurement system, then measuring the time it takes for this voltage to decay to a threshold level—the capacitive nonlinearity causes this time delay to be dependent upon the dc input voltage whose value is being measured.

McKenzie, G.; Record, P.

2012-04-01

462

400Ah lithium-ion cells for telecommunications systems and DC power supply systems  

Microsoft Academic Search

To expand the application of lithium-ion batteries in back-up power supplies for telecommunications equipment, we manufactured large-capacity 200-Ah and 400-Ah lithium-ion cells and measured their characteristics. We also propose a lithium-ion battery management system that charges cells individually to replace the conventional system in which a cell voltage equalizing circuit is installed in parallel with the cells. We constructed a

Toshio MATSUSHIMA; Nobuhiko SUZUKI

2008-01-01

463

Wires by Patchy Particles  

NSDL National Science Digital Library

Simulation Software: Glotzer Group Code Simulation Method: Brownian Dynamics A system of 80 spherical particles with two patches at a concentration of 0.20, was run starting at an effectively infinite temperature then instantaneously quenched to a temperature of 0.5. The final equillibrium structure is wires or chains. Simulation Model: United Atom Rigid Body with Lennard-Jones

Zhang, Zhenli

2005-01-31

464

Design of a low swing power-efficient output stage for DC-DC converters  

Microsoft Academic Search

DC-DC converter is required to supply various DC voltage levels from battery to logic devices for most of the portable systems, such as cellular phone, portable DVD, CD player, etc. As the energy capacity of a battery is usually very limited, DC-DC converter with high efficiency over the entire load range is necessary to extend the battery life time. In

Jiahong Lao; Meng Tong Tan

2009-01-01

465

A Nonisolated Bidirectional ZVS-PWM Active Clamped DC–DC Converter  

Microsoft Academic Search

Power electronic converter systems for applications such as telecom, automotive, and space can have dc voltage buses that are backed up with batteries or supercapacitors. These batteries or supercapacitors are connected to the buses with bidirectional dc-dc converters that allow them to be discharged or charged, depending on the operating conditions. Bidirectional dc-dc converters may be isolated or nonisolated depending

Pritam Das; Brian Laan; Seyed Ahmad Mousavi; Gerry Moschopoulos

2009-01-01

466

Diverse strategies engaged in establishing stereotypic wiring patterns among neurons sharing a common input at the visual system's first synapse  

PubMed Central

Sensory circuits use common strategies such as convergence and divergence, typically at different synapses, to pool or distribute inputs. Inputs from different presynaptic cell types converge onto a common postsynaptic cell, acting together to shape neuronal output (Klausberger and Somogyi, 2008). Also, individual presynaptic cells contact several postsynaptic cell types, generating divergence of signals. Attaining such complex wiring patterns relies on the orchestration of many events across development, including axonal and dendritic growth and synapse formation and elimination (reviewed by Waites et al., 2005; Sanes and Yamagata, 2009). Recent work has focused on how distinct presynaptic cell types form stereotypic connections with an individual postsynaptic cell (Williams et al., 2011; Morgan et al., 2011), but how a single presynaptic cell type diverges to form distinct wiring patterns with multiple postsynaptic cell types during development remains unexplored. Here we take advantage of the compactness of the visual system's first synapse to observe development of such a circuit in mouse retina. By imaging three types of postsynaptic bipolar cells and their common photoreceptor targets across development, we found that distinct bipolar cell types engage in disparate dendritic growth behaviors, exhibit targeted or exploratory approaches to contact photoreceptors, and adhere differently to the synaptotropic model of establishing synaptic territories. Furthermore each type establishes their final connectivity patterns with the same afferents on separate time-scales. We propose that such differences in strategy and timeline could facilitate the division of common inputs among multiple postsynaptic cell types to create parallel circuits with diverse function.

Dunn, Felice A.; Wong, Rachel O.L.

2012-01-01

467

A novel approach to modeling and identifying the double loop DC motor driving system in soccer robots  

NASA Astrophysics Data System (ADS)

Using double loop DC motor drive system (DLM) of the RoboCup middle size robots as research subject, the model of DLM has been reduced to a simple state space one by the "quasi-equivalent" modeling method, based on the characteristic analysis of the system. Further, the parameters of the model can be exactly identified applying the improved genetic algorithm. The results of compared experiment proved that using this model and identification ways can get a reasonably structural and high parameters precision model. The model can describe the DLM to design the control system for robot soccer.

Li, Yonglong; Li, Zushu; Li, Jun; Wang, Niu

2007-12-01

468

Thermodynamics of a closed-cycle gas flow system for cooling a HTc DC-squid magnetometer  

NASA Astrophysics Data System (ADS)

A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the interface between the SQUID unit and the cooler (a Leybold Heraeus RG 210). In this paper the prototype system is shortly described, its thermodynamic behaviour is considered and simulations are compared with experimental results.

van den Bosch, P. J.; Ter Brake, H. J. M.; van den Eijkel, G. C.; Boelens, J. P.; Holland, H. J.; Verberne, J. F. C.; Rogalla, H.

469

A high frequency link direct dc-ac converter for residential fuel cell power systems  

Microsoft Academic Search

This paper describes a boost converter cascaded high frequency link direct dc-ac converter suitable for fuel cell power sources. A new multi-loop control for a boost converter to reduce the low frequency input current harmonics drawn from the fuel cell is proposed. A new PWM technique for the cycloconverter at the secondary to reject the low order harmonics in the

Yu Jin Song; Prasad N. Enjeti

2004-01-01

470

DC-free multimode code design using novel selection criteria for optical recording systems  

Microsoft Academic Search

DC-free run-length limited codes have been the cornerstone of all three generations of optical recording, CD, DVD and BD. Research into very efficient coding methods is paramount for the upcoming fourth generation. Guided Scrambling (GS) is an efficient coding method that has been reported in the literature. Under GS rules, a user word is translated into a plurality of possible

Jun Lee; Kees A. Schouhamer Immink

2009-01-01

471

Modelling and Analysis of Permanent Magnet Excited Brushed DC Motor for Underwater Propulsion System  

Microsoft Academic Search

In this paper, we present modelling and analysis of permanent magnet excited brushed dc motors which are meant for use as an electrically actuated thruster in underwater remotely operated vehicles (ROVs). Using the general solutions to the Laplacian\\/quasi-Poissonian magnetic field equations in the motor airgap and then applying with appropriate boundary conditions, normal and tangential components of flux density in

M. F. Zainal Abidin; Dahaman Ishak

2009-01-01

472

A robust 6 kW variable DC power supply with closed loop control system  

Microsoft Academic Search

In this paper, a development of a 6 kW variable DC power supply hardware implementation is presented. The power supply design is based on switched mode power supplies technology. This power supply provides variable output voltages of 10, 20, 30, 40, 50, and 60 V. Effective low cost techniques were employed. The power supply circuit is composed of three main

Yousif Adam; Norman Mariun; Ishak Aris

2000-01-01

473

DC Electronics  

NSDL National Science Digital Library

This is a website with many learning objects on DC Electronics with over 60 lessons in areas including: Basic Concepts, Electrical Circuits / Meters, Ohm's Law, Magnetism, Parallel Circuits, Series/Parallel Circuits, Series/Parallel Applications and Series Circuits.

2012-10-18

474

Superconducting wires  

SciTech Connect

The requirement of high critical current density has prompted extensive research on ceramic processing of high-T/sub c/ superconductors. An overview of wire fabrication techniques and the limitations they impose on component design will be presented. The effects of processing on microstructure and critical current density will also be discussed. Particle alignment has been observed in extruded samples which is attributed to high shear stresses during plastic forming. Composites of superconductor and silver in several configurations have been made with little deleterious effect on the superconducting properties. 35 refs., 2 figs., 1 tab.

Lanagan, M.T.; Poeppel, R.B.; Singh, J.P.; Dos Santos, D.I.; Lumpp, J.K.; Dusek, J.T.; Goretta, K.C.

1988-06-01

475

Current dependence of heat leak on the terminals in the superconducting DC transmission and distribution system of CASER-2  

NASA Astrophysics Data System (ADS)

Superconductivity can solve the energy problems in the world as energy saving technologies. In particular, superconducting direct current (DC) transmission and distribution (T&D) systems is promising, as it can be easily extended to large scale energy transmission systems for energy sharing. We are developing criogenic systems for effective cooling of superconducting T&D systems. In the cooling experiments with the 200 m-class superconducting DC T&D system at Chubu University (CASER-2), we have estimated the performance of the system. For example, our superconducting cable is connected to the outside at the terminals using Peltier current leads (PCLs). The PCL is composed of a thermoelectric material and a copper lead. Small thermal conductivity and large thermopower of the thermoelectric modules can effectively insulate the heat leak to the low temperature end. We measured the temperature along the current leads and the heat leak at the terminals. As current leads have an optimal shape factor, the optimum operation current exists. The current dependence of the system performance is discussed.

Kawahara, Toshio; Watanabe, Hirofumi; Emoto, Masahiko; Hamabe, Makoto; Yamaguchi, Sataro; Hikichi, Yasuo; Minowa, Masahiro

2012-12-01

476

Measurement of the size and spacing of standard wire sieves using an image processing system and wavelet transform  

Microsoft Academic Search

A new methodology using image processing and wavelet transform is investigated to measure the size of the wire sieves and\\u000a their spacing. Wire sieves are used in pharmaceuticals\\/chemical industries for filtering the grains of chemical powder. Experimental\\u000a results show measurement that the diameter and spacing of the wire in the sieves can be measured with the accuracy of 1um\\u000a and

K. P. Chaudhary; Chandra Shakher; Shashi K. Singh

2011-01-01

477

Increase of the Efficiency for a Solar Renewable Source Using a Soft Switched DC-DC Boost Converter  

Microsoft Academic Search

An important role in the solar renewable energy sources play a DC-DC power converter that transforms the electric energy provided by a photovoltaic (PV) system in DC energy to be used for DC loads or to be stored in high capacity battery. This paper presents a new type of active snubber for DC-DC boost converters that can be used in

N. D. Trip; A. Schiop; M. Tomse

2007-01-01

478

DC-DC conversion powering for the CMS tracker at SLHC  

NASA Astrophysics Data System (ADS)

A tracker powering scheme based on DC-DC converters close to the detector modules can supply more power through thinner cables. This will allow to satisfy the increased power demands of tracking systems at the SLHC. This article describes the development of DC-DC converters for upgrades of the CMS pixel and tracking systems and addresses system integration issues.

Feld, L.; Jussen, R.; Karpinski, W.; Klein, K.; Merz, J.; Sammet, J.

2011-02-01

479

Preparation and characterization of hydrogenated carbon nitride films synthesized by dual DC-RF plasma system  

Microsoft Academic Search

Carbon nitride films (CNx films) were deposited on Si(100) substrates making use of dual direct current radio frequency (DC-RF) plasma enhanced chemical vapor deposition (PECVD), using a mixed gas of CH4 and N2 as the source gas. The microstructures, morphologies, and compositions of the resulting CNx films were analyzed by means of atomic force microscopy (AFM), transmission electron microscopy (TEM),

Junying Hao; Tao Xu; Weimin Liu

2005-01-01

480

Plastic-molded LTS DC-SQUIDs for multichannel biomagnetic measurement systems  

Microsoft Academic Search

A plastic molding technique for SQUIDs has been developed to protect the chip from moisture damage. A 1.5-mm-thick layer of molding compound (epoxy resin, elastic resin, and silica powder) was poured over Ketchen-type DC-SQUID that has Nb\\/AlOx\\/Nb Josephson junctions. The moisture resistance of these plastic-molded SQUIDs was examined by subjecting them to temperature and humidity storage tests (60°C, 90% relative

Yukihiro Utaka; T. Kido; K. Kudo

1997-01-01

481

Quench protection system using a novel d.c. circuit breaker for LHD  

Microsoft Academic Search

The large helical device (LHD) has 12 superconducting coils that are strongly coupled with each other. The rating currents of these coils are from 13 to 32 kA and total magnetically stored energy reached 1.6 GJ. These coils are excited by six d.c. power supplies and each coil current is controlled with high accuracy to make a magnetic surface required

H Chikaraishi; S Tanahashi; S Yamada; J Yamamoto; O Motojima; T Satoh; H Niwa

1998-01-01

482

An energy-efficient low voltage DC grid powered smart LED lighting system  

Microsoft Academic Search

Inefficiency of the common lightings like incandescent, fluorescent and halogen lamps presents an ample opportunity to retrofit high efficacy, long life-time and low maintenance LED solid-state lighting, which has significantly reduced in cost on an annual basis. LED lights and many electronic loads used within in-built environment are DC in nature. As such, in this paper, an energy-efficient low voltage

L. H. Koh; Yen Kheng Tan; Z. Z. Wang; King Jet Tseng

2011-01-01

483

Low-loss DC to AC converter system for stand alone photovoltaic applications  

Microsoft Academic Search

A composite converter with a high-frequency link was investigated for stand alone DC-to-AC-conversion applications such as batteries charged by photovoltaic panels. The secondary converter was a supply-commutated high-frequency bridge, while the primary inverter was investigated further. A center-tap transformer inverter was chosen, and two approaches were used to minimize switching losses. The first approach was to implement regenerative snubbers. The

C. J. Simpson; J. D. van Wyk; J. J. Schoeman

1992-01-01

484

Modeling of a supersonic DC plasma torch system for carbon nanotube production  

NASA Astrophysics Data System (ADS)

The carbon nanotube (CNT) structure forms a very promising source material. It has unique properties such as high thermal and electrical conductivities, and a very high mechanical strength. In recent years, researchers were able to improve both the quantity and quality of the CNT production. Among the efforts made to scale up the production, Harbec and Meunier designed a new plasma torch process for the industrial production of CNT in bulk powder form. Their process is based on the DC plasma-jet pyrolysis of a carbon-containing gas. Experiments were conducted using either 100 slpm of argon or 225 slpm of helium. Tetrachloroethylene (C2Cl4, or TCE) was selected as the carbon raw material. The present work focuses on the modeling of this CNT synthesis process and aims at an understanding of the physical and chemical phenomena observed in this system. First, a description is made of the temperature and flow fields, as well as the species concentration distribution in the torch nozzle using both possibilities of He or Ar as the plasma gas. This is followed in the second part of the thesis by a model aimed to study the nucleation and evolution of the metal particles acting as catalyst for CNT growth in the nozzle. In the third part, the modeling of the TCE pyrolysis process in the flow was carried out. The fluid dynamics equations are used in this system showing supersonic characteristics. A realizable k-? model is used to address the turbulent effects in the flow fields. The moment method is employed to calculate the formation of the fine catalyst particles from the metal vapor injected. Within the supersonic domain of the flow field, the influence of existing shock waves on the particle nucleation is discussed, as well as the chemical reactions involved. Results show that the supersonic phenomena make it possible for metal particles to nucleate and be maintained in small sizes. This however also causes a backflow in the nozzle, which partially contributes to the experimentally observed soot deposition and CNT growth within the nozzle. The carbon containing gas experiences a fast dissociation process once it enters the nozzle. The produced carbon species are maintained in small clusters of carbon atoms in the high temperature environment within the nozzle. These clusters and atoms serve as the source of CNT growth and form a layer of carbon deposit on the surface of the nozzle. This deposited layer acts as a thermal insulator changing the conditions in the nozzle, particularly on the wall. A modeling of this effect is performed, confirming that the basic requirements for CNT growth are attained within the nozzle itself. A parametric study of the process is carried out and suggestions are made on the geometry of the reactor and the operating parameters for the formation of CNT. These modeling results suggest that the process can be optimized with carefully chosen operating parameters. With the specific design of the nozzle used here, it is recommended to operate at lower pressures in the reactor in order to avoid a backflow in the nozzle. Different kinds of metal catalyst can be used in this system and the reactor length should be adjusted accordingly in order to optimize the outcome of the process.

Guo, Liping

485

Silver discharge electrode for suppression of ozone generation in positive dc corona  

Microsoft Academic Search

The aim of this paper is to suppress the ozone production in dc corona discharges, and is to report the effect of material of the discharge electrode on the ozone production. In this study, corona discharges were generated in a coaxial wire-cylinder reactor stressed by positive or negative dc voltage. A set of high purity wires made of different metals,

A. Yehia; A. Mizuno

2005-01-01

486

Comparative analysis of full bridge and half bridge current resonant DC-DC converter  

Microsoft Academic Search

This paper deals with a comparative analysis of full bridge and half bridge current resonant DC-DC converter. The novel current resonant DC-DC converter has been proposed to improve the power efficiency. The full bridge DC-DC converter is suitable for the low input voltage and large input current as in the fuel cell power supply system, and the half bridge one

Hisatsugu Kato; Hirofumi Matsuo; Tsubasa Ito; Shuhei Kawazu; Daiki Kawahara; Satoshi Motomura; Ryota Hamaguchie

2011-01-01

487

Composite Superconducting Wires Obtained by High-Rate Tinning in Molten Bi-Pb-Sr-Ca-Cu-O System.  

National Technical Information Service (NTIS)

The preparation of high-T(sub c) superconducting long composite wires by short-time tinning of the metal wires in a molten Bi-Pb-Sr-Ca-Cu-O compound is discussed. The application of this method to the high-T(sub c) materials is tested, possibly for the fi...

A. D. Grozav L. A. Konopko N. I. Leporda

1990-01-01

488

Current Limiting Experiment of Transformer Type Superconducting Fault Current Limiter With Rewound Structure Using BSCCO Wire in Small Model Power System  

Microsoft Academic Search

Superconducting fault current limiters (SFCLs) are expected to improve the reliability and stability of power systems. We have proposed new design of a transformer type SFCL whose primary and secondary superconducting coil has rewound struc- ture. The fundamental characteristics of the proposed SFCL were investigated using a small model designed and made with BSCCO wire. This paper describes on the

Sayaka Oda; Sho Noda; Hideyoshi Nishioka; Masato Mori; Jumpei Baba; Yasuyuki Shirai

2011-01-01

489

Composite ceramic superconducting wires for electric motor applications  

NASA Astrophysics Data System (ADS)

A scaled-up process for producing sintered, silver coated YBCO mono filament wire was developed and is currently able to produce 30 meters of wire/day. Efforts aimed at improving the electrical performance of this wire are well underway. Two approaches are being used: Continuously melt-texturing sintered YBCO wire/fiber to produce a macro-crystalline, strong-linked wire, and adaptation the TBCO process to the production of BiSCCO wire which can be subsequently mechanically textured by rolling the wire into ribbon. Work has also proceeded on the fabrication of a brushless DC trapped flux motor in which melt-textured YBCO rings are used as permanent magnet replicas. This motor design holds the potential for a high power HTSC motor which can be fabricated using current HTSC technology.

Hodge, James D.

1990-09-01

490

Hot-wire anemometry  

Microsoft Academic Search

A brief historical survey of hot-wire anemometry is presented and questions of hot-wire response are investigated, taking into account sensor properties, steady-heat-loss laws, the dynamic response of the wires, the sensitivity coefficients of the wires, the characteristics of a wire of finite length, the spatial resolution of hot wires, and the aerodynamic perturbations of the probes. A description of electronic

G. Comte-Bellot

1976-01-01

491

NASA wiring for space applications program  

NASA Astrophysics Data System (ADS)

An overview of the NASA Wiring for Space Applications Program and its relationship to NASA's space technology enterprise is given in viewgraph format. The mission of the space technology enterprise is to pioneer, with industry, the development and use of space technology to secure national economic competitiveness, promote industrial growth, and to support space missions. The objectives of the NASA Wiring for Space Applications Program is to improve the safety, performance, and reliability of wiring systems for space applications and to develop improved wiring technologies for NASA flight programs and commercial applications. Wiring system failures in space and commercial applications have shown the need for arc track resistant wiring constructions. A matrix of tests performed versus wiring constructions is presented. Preliminary data indicate the performance of the Tensolite and Filotex hybrid constructions are the best of the various candidates.

Schulze, Norman

1995-11-01

492

Fabrication of tungsten wire needles  

SciTech Connect

Fine point needles for field emissoin are conventionally produced by electrolytically or chemically etching tungsten wire. Points formed in this manner have a typical tip radius of about 0.5 microns and a cone angle of some 30 degrees. The construction of needle matrix detector chambers has created a need for tungsten needles whose specifications are: 20 mil tungsten wire, 1.5 inch total length, 3 mm-long taper (resulting in a cone angle of about 5 degrees), and 25 micron-radius point (similar to that found on sewing needles). In the process described here for producing such needles, tungsten wire, immersed in a NaOH solution and in the presence of an electrode, is connected first to an ac voltage and then to a dc supply, to form a taper and a point on the end of the wire immersed in the solution. The process parameters described here are for needles that will meet the above specifications. Possible variations will be discussed under each approprite heading.

Roder, A.

1983-02-01

493

Design of DC\\/DC Boost converter with FNN solar cell Maximum Power Point Tracking controller  

Microsoft Academic Search

This paper demonstrates the Maximum Power Point Tracking (MPPT) controller that uses a DC\\/DC Boost converter with a Fuzzy Neural Network (FNN) system. It simplifies the topology of the DC\\/DC boost converter model to state equations, which is easy to simulate with Matlab. Additionally, the FNN system uses an integrated Fuzzy and Neural Network (NN), which advantages include uncertainty information

Hung-Ching Lu; Te-Lung Shih

2010-01-01

494

DC Transformer.  

National Technical Information Service (NTIS)

A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply ca...

C. M. Ihlefeld R. C. Youngquist S. O. Starr

2013-01-01

495

Snow loads on wire mesh and cable net rockfall slope protection systems  

Microsoft Academic Search

Snow load on mesh systems is complicated by many factors. This paper presents field instrumentation data on snow load variation with temperature, snowfall and snow depth on a mesh system. It was found that snow load pattern on mesh systems changed with temperature even without variation in snow depth. It reached its maximum value when the temperature rose just above

Shanzhi Shu; Balasingam Muhunthan; Thomas C. Badger

2005-01-01

496

Wired and wireless intrusion detection system: Classifications, good characteristics and state-of-the-art  

Microsoft Academic Search

In computer and network security, standard approaches to intrusion detection and response attempt to detect and prevent individual attacks. Intrusion Detection System (IDS) and intrusion prevention systems (IPS) are real-time software for risk assessment by monitoring for suspicious activity at the network and system layer. Software scanner allows network administrator to audit the network for vulnerabilities and thus securing potential

Tarek S. Sobh

2006-01-01

497

An Electro-Rheological (er) Robotic System:. Controller Validation, Trend Study, Comparison with DC Servomotors, Position Repeatability  

NASA Astrophysics Data System (ADS)

Industrial robot arms experience position inaccuracies due to the output cogging torques of the DC servomotors. Therefore, in an attempt to resolve these position problems, an electro-rheological (ER) robotic system is considered as an actuator to drive the robot arm rapidly in both directions. This ER robotic system consists of two ER clutches, an ER brake, a gear train, an encoder and a robot arm. The ER clutches produce clockwise and anti-clockwise rotations. The ER brake decelerates and halts the robot arm. The main aim of this paper is to validate a controller model of the ER robotic arm. Next, a trend study is used to determine the optimum working conditions of the ER actuated-robotic arm. The robotic displacements of both the ER rotary devices and the commercial DC servomotors are compared in terms of position accuracy and speed of response. Finally, the repeatability of the robotic end positions is examined in order to determine the importance of the ER brake.

Tan, K. P.; Stanway, R.; Bullough, W. A.

498

dc overcurrent protection -- Where we stand  

Microsoft Academic Search

Most dc systems require some form of overcurrent and\\/or short circuit protection. These systems include dc motor drives and controllers, semiconductor components, telecommunications switching stations (both power and signal), and transit substations. Battery-powered applications from automobiles and lift trucks to Uninterruptible Power Supply (battery backup) systems also require dc overcurrent protection. As with any fuse selection, the three elements of

Brozek

2009-01-01

499

Windows: Life after Wire.  

ERIC Educational Resources Information Center

|Although wired glass is extremely common in school buildings, the International Building Code adopted new standards that eliminate the use of traditional wired glass in K-12 schools, daycare centers, and athletic facilities. Wired glass breaks easily, and the wires can cause significant injuries by forming dangerous snags when the glass breaks.…

Razwick, Jerry

2003-01-01

500

47 CFR 68.213 - Installation of other than âfully protectedâ non-system simple customer premises wiring.  

Code of Federal Regulations, 2011 CFR

...modifications to existing installations, copper conductors shall be, at a minimum, solid, 24...Building Wiring Standards. (2) Conductors shall have insulation with a 1500...between the foil and all of the individual conductors connected together, such...

2011-10-01