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1

The design of controller of buck converter  

Microsoft Academic Search

State-space averaging method is a powerful way to treat analysis and control problems for variable structure systems. The transfer function model of the buck converter is proposed by using the State-space averaging method. A compensator device of the system is designed by using the knowledge of the series compensation. And the stability of the closed-loop Buck system has greatly improved.

Qiang He; Yixin Zhao

2010-01-01

2

Synchronous Buck Converter based PV Energy System for Portable Applications  

Microsoft Academic Search

Synchronous buck converter based photo voltaic (PV) energy system for portable applications is presented in this paper; especially to charge the batteries used in mobile phones. The main advantage of using synchronous buck converter is to reduce the switching loss in the main MOSFET over conventional dc-dc buck converter. The switching loss is minimized by applying soft switching techniques such

B. ChittiBabu; S. R. Samantaray; Nikhil Saraogi; M. V. Ashwin Kumar; R. Sriharsha; S. Karmaker

2011-01-01

3

Bifurcation behavior of the buck converter  

Microsoft Academic Search

The DC-DC buck power converter, a widely used chopper circuit, exhibits subharmonics and chaos if current feedback is used. This paper investigates the dependence of the system behavior on its parameters. The bifurcation phenomena and a mapping of the parameter space have been presented. This knowledge is vital for designing practical circuits

Krishnendu Chakrabarty; Goutam Poddar; Soumitro Banerjee

1996-01-01

4

Buck-flyback dc-dc converter  

NASA Astrophysics Data System (ADS)

It is difficult to obtain a large input/output voltage ratio with a dc-dc converter, because the duty factor d may not reach very small values. For the same reason, it is difficult to obtain an output voltage that is adjustable in a large range. A dc-dc converter circuit is proposed that overcomes this limitation by performing a voltage ratio d2/(1 - d) in the best operating mode. Circuit operation is analyzed, operating modes are evidenced, and the voltage ratio is deduced in each operating mode as a function of output current, duty factor, and circuit component values. Boundary conditions between different operating modes are obtained; consequently, it is concluded that these conditions do not occur for some operating modes. Finally, component ratings are summarized, to facilitate circuit design. The buck-flyback dc-dc converter is very suitable for low-voltage (e.g., computer) power supplies and for power supplies with the output voltage (adjustable in a large range) supplied from the mains without a mains voltage transformer.

Birca-Galateanu, Serban

1988-11-01

5

Multifrequency Small-Signal Model for Buck and Multiphase Buck Converters  

Microsoft Academic Search

To investigate the high-frequency behaviors of buck and multiphase buck converters, this paper develops a modeling method based on the harmonic-balance approach. Because the nonlinear pulse-width modulator generates sideband components, the sideband effect occurs in a closed-loop converter. Taking this effect into account, the multifrequency small-signal model is proposed, which is applicable beyond half of the switching frequency. In a

Yang Qiu; Ming Xu; Kaiwei Yao; Juanjuan Sun; Fred C. Lee

2006-01-01

6

Interleaving Energy-Conservation Mode (IECM) Control in Single-Inductor Dual-Output (SIDO) Step-Down Converters With 91% Peak Efficiency  

Microsoft Academic Search

The proposed single-inductor dual-output (SIDO) converter with interleaving energy-conservation mode (IECM) control is designed using 65 nm technology to power the ultra-wide band (UWB) system. The energy-conservation mode (ECM) con- trol generates four different energy delivery paths for dual buck outputs with only one inductor. In addition, the superposition technique is used to achieve a minimized inductor current level. The

Yu-Huei Lee; Yao-Yi Yang; Shih-Jung Wang; Ke-Horng Chen; Ying-Hsi Lin; Yi-Kuang Chen; Chen-Chih Huang

2011-01-01

7

Buck converter associated with active clamp flyback converter for PV power system  

Microsoft Academic Search

This paper presents an LED lighting system with a PV source. The circuit structure of the proposed system separately adopts buck converter and flyback converter as the charger and discharger. With this circuit structure, buck converter can vary its duty ratio to regulate charging current of battery, while flyback converter with active clamp circuit can recover energy stored in leakage

S.-Y. Tseng; Y.-J. Li; Y.-J. Wu

2008-01-01

8

Buck-Boost Converter Associated with Active Clamp Forward Converter for PV Power System  

Microsoft Academic Search

This paper presents an LED lighting system with a PV source. The circuit structure of the proposed system adopts buck-boost converter associated with forward converter. In this research, buck-boost converter is used as a charger for charging battery, and forward converter with active clamp circuit is adopted to drive LED lighting, and to respectively recover and reset energies stored in

S.-Y. Tseng; W.-C. Chen; Y.-J. Li; J.-S. Kuo

2007-01-01

9

A buck-boost bidirectional converter to drive piezoelectric actuators  

Microsoft Academic Search

The present work deals with the development and control of a converter to drive piezoelectric actuators. In order to maximize the field in the piezoelectric ceramic important voltages are needed. To fulfill such requirements with a limited input voltage a bidirectional buck-boost converter is proposed. The converter is controlled by means of a sliding mode control strategy. The converter is

Oriol Gomis-Bellmunt; Daniel Montesinos-Miracle; Samuel Galceran-Arellano; A. Sudria-Andreu

2007-01-01

10

Three-Level ZVS Active Clamping PWM for the DC–DC Buck Converter  

Microsoft Academic Search

This paper presents the study of a dc-dc buck converter with three-level buck clamping (buck-buck), zero-voltage switching (ZVS), active clamping, and constant-frequency pulsewidth modulation (PWM). Other ZVS dc-dc converter topologies that employ three-level switching cells are introduced, and their steady-state dc gain is analyzed. This analysis shows that the buck-buck converter has characteristics that warrant a more detailed study. A

Jean Paulo Rodrigues; A. J. Perin; S. A. Mussa; M. L. Heldwein

2009-01-01

11

Robust nonlinear adaptive control of multiphase synchronous buck power converters  

Microsoft Academic Search

The problem of controlling multiphase synchronous buck power converters is considered. The aims are to regulate the output voltage of the converter and to ensure adequate current sharing between its different channels. Using the backstepping technique, an adaptive controller is designed based on a large-signal bilinear model of the whole multi-channel converter. A parameter projection is used to ensure that

H. El Fadil; F. Giri

2009-01-01

12

Autotuning of Digitally Controlled Buck Converters Based on Relay Feedback  

Microsoft Academic Search

This paper proposes a simple autotuning technique for digitally controlled dc-dc synchronous buck converters. The proposed approach is based on the relay feedback method and introduces perturbations on the output voltage during converter soft-start. By using an iterative procedure, the tuning of PID parameters is obtained directly by including the controller in the relay feedback and by adjusting the controller

W. Stefanutti; P. Mattavelli; S. Saggini; M. Ghioni

2005-01-01

13

A new PWM control strategy for the buck converter  

Microsoft Academic Search

A new PWM control strategy for the buck converters is presented. The proposed control strategy is based on the switching converter large signal average model linearization and use modern control theory to achieve the control laws for the expected response. Therefore, a new nonlinear PWM controller is made to implement the control law. The new nonlinear PWM controller development is

Chao-Cheng Wu; Chung-Ming Young

1999-01-01

14

Modeling and design of feedback loops for a voltage-mode single-inductor dual-output buck converter  

Microsoft Academic Search

In recent years, single-inductor dual-output (SIDO) converters have found applications in hand-held electronic devices. The focus of the paper is about the modeling and the design of the feedback control loop for a voltage-mode SIDO buck converter working in continuous conduction mode. A small-signal model was developed and verified by simulations and experimental results. This model is practically useful in

Kun-Yu Lin; Chun-Shih Huang; Dan Chen; Kwang H. Liu

2008-01-01

15

A Fixed-frequency Sliding Mode Controller for Buck Converter in Continuous Conduction Mode  

Microsoft Academic Search

This paper proposes a novel fixed-frequency sliding mode (SM) controller of buck converters in CCM (continuous conduction mode), which almost holds the advantage of robustness and fastness of SM control. The design method of a new SM controller for buck converter is given. Simulation and experimental results verify the validity and feasibility of the fixed-frequency modulation method in Buck converter

Yu Ni; Jianping Xu

2009-01-01

16

A New Resonant Gate Drive Circuit for Synchronous Buck Converter  

Microsoft Academic Search

This paper proposes a new resonant gate drive circuit for driving both the control metal oxide semiconductor field effect transistor (MOSFET) and synchronous MOSFET in a synchronous buck converter. The circuit can recover more than 70% of the conventional gate drive loss. More importantly, the driving circuit can also reduce the switching loss. It charges and discharges the gate of

Zhihua Yang; Sheng Ye; Yan-Fei Liu

2007-01-01

17

A new resonant gate drive circuit for synchronous buck converter  

Microsoft Academic Search

The paper proposed a resonant gate drive circuit for buck converter with synchronous rectifier. The circuit can recover more than 50% of the conventional gate drive loss. It charges and discharges the gate of MOSFET at constant current. It can also reduce the switching loss significantly. Other advantages of the proposed circuit include better noise immunity for dv\\/dt turn on,

Zhihua Yang; Sheng Ye; Yan-Fei Liu

2006-01-01

18

Fast and Accurate Current Sensing in a Multiphase Buck Converter  

Microsoft Academic Search

Voltage regulator modules (VRM), which are used to power advanced microprocessors, have stringent efficiency and transient response requirements. A multiphase buck converter scheme with inner current loop control is one of the candidates for use in this application because of its ability to achieve fast dynamic current response under step-load conditions. In order to realize the full potential of the

Hadja Marecar; R. Oruganti

2005-01-01

19

Buck quasi-resonant converter operating at constant frequency: analysis, design, and experimentation  

Microsoft Academic Search

A buck pulsewidth modulated zero-current switching quasi-resonant converter (buck PWM ZCS QRC) operating at constant frequency is discussed. Operating principle and design-oriented analysis are presented with normalized design curves, design procedure, design example, simulations, and experimental results. The new topology, which can be considered as a particular one, is compared with the well-established buck frequency-modulated zero-current switching quasi-resonant converter (buck

I. Barbi; J. C. O. Bolacell; D. C. Martins; F. B. Libano

1990-01-01

20

Buck-flyback dc-dc converter  

Microsoft Academic Search

It is difficult to obtain a large input\\/output voltage ratio with a dc-dc converter, because the duty factor d may not reach very small values. For the same reason, it is difficult to obtain an output voltage that is adjustable in a large range. A dc-dc converter circuit is proposed that overcomes this limitation by performing a voltage ratio d2\\/(1

Serban Birca-Galateanu

1988-01-01

21

Capacitor charge balance control strategy of Buck converter  

Microsoft Academic Search

Taking buck converter for example, this paper studies the non-linear characteristics and capacitance charge-balance control strategy of switching regulations systems under large-signal disturbance. In order to reduce the transient overshoot and recovery time of the output voltage under large-signal disturbance, the paper adopts capacitive charge-balance principle, deduces a new digital control algorithm and builds the Matlab simulation model for this

Yaai Chen; Jinghua Zhou; Weiping Zhang; Weihai Li; Songlin Xie

2009-01-01

22

Design of controller for buck-boost converter  

Microsoft Academic Search

The problem of output regulation with guaranteed transient performances for buck-boost converter with inverting topology is discussed. The fast dynamical controller with the relative highest derivative of output signal in feedback loop is used. Consequently, two-time-scale motions are induced in the closed-loop system. Stability conditions imposed on the fast and slow modes and sufficiently large mode separation rate can ensure

V. D. Yurkevich

2005-01-01

23

Invariant sets techniques for buck DC-DC converter control  

Microsoft Academic Search

This paper presents a simple and effective method for feedback law synthesis using invariant sets techniques. Given a time-varying Buck DC-DC converter affected by perturbations and constraints, the proposed method gives the best feedback gain in terms of finding the maximal invariant ellipsoidal set. This approach assures a good robustness but may lead to slow closed-loop performances and therefore a

Anamaria Luca; Pedro Rodríguez-Ayerbe; Didier Dumur; Pierre Lefranc

2010-01-01

24

Buck-Boost Combined with Active Clamp Flyback Converter for PV Power System  

Microsoft Academic Search

This paper presents an LED lighting system with PV sources. The circuit of the proposed system adopts buck-boost converter associated with flyback converter to charge battery and to drive an LED lighting system. In this research, buck-boost converter is used as a charger for charging battery, and flyback converter with active clamp circuit is adopted to drive the LED lighting.

S.-Y. Tseng; J.-S. Kuo; S.-W. Wang; C.-T. Hsieh

2007-01-01

25

PV power system using buck\\/forward hybrid converters for LED Lighting  

Microsoft Academic Search

This paper presents an LED lighting system with a PV source. The circuit structure of the proposed system adopts buck converter combined with forward converter. In this research, buck converter is used as a charger for charging battery, and forward converter with active clamp circuit , which can recover leakage inductor energy and reset magnetizing energy stored in the transformer,

S.-Y. Fan; S.-Y. Tseng; Y.-J. Wu; J.-D. Lee

2009-01-01

26

Analysis and experimental results of switched-resonator-based buck-boost and inverting-buck converters  

Microsoft Academic Search

Two resonant DC-DC converters are presented where an LC tank is switched by an inverter. One of the presented topologies is buck-boost and the other one is inverting-buck converter. Few numbers of elements are employed, turn-on and turn-off ZCS conditions are provided for all active elements, energy circulation is reduced, and, power transferring is automatically stopped at output short-circuited. Experimental

M. Jabbari; H. Farzanefard

2010-01-01

27

Simulation and study of photovoltaic cell power output characteristics with buck converter load  

Microsoft Academic Search

This paper present the study of photovoltaic cell (PV Cells) output power characteristics by experimenting with the simulation of equivalent circuit and of output behavior of photovoltaic while connected to the buck converter, with adjustment of its duty ratio (D). Experimental result show that the maximum power point (MPP) is reduced 24 %, while connected to the buck converter load

A. Bilsalam; J. Haema; I. Boonyaroonate; V. Chunkag

2011-01-01

28

A prototype of a fuel cell PEM emulator based on a buck converter  

Microsoft Academic Search

After a brief introduction about fuel cell systems, and their modelling, this paper proposes a possible solution to emulate a proton exchange membrane fuel cell (PEM-FC) system by using a DC–DC buck converter. The fuel cell system, including all its auxiliaries and related control systems, is emulated by a buck converter realized experimentally and controlled in the DSPACE environment. The

Giuseppe Marsala; Marcello Pucci; Gianpaolo Vitale; Maurizio Cirrincione; Abdellatif Miraoui

2009-01-01

29

Output feedback H-infinity control for buck converter with uncertainty parameters  

Microsoft Academic Search

This paper addresses the problem of output feedback H? controller design for buck converter with multiple parameters uncertainty. The parameter uncertainty model of buck converter is built by method of first-order Taylor approximation. Based on the model, the solvability condition for the existence of output feedback H? controller is derived in the form of linear matrix inequality according to H?

Yan-hua Xian; Jiu-chao Feng

2011-01-01

30

Buck converter with a new driving circuit in a TV power system  

Microsoft Academic Search

In this letter, a new buck converter of a TV power system is presented. First, we devised a driving circuit for an emitter-coupled type buck converter, by which it is possible to reduce the material cost of transformers and voltage stress of power device. Second, we adopted a hybrid oscillation technique. After self-oscillating mode feeds initial standby power, main power

Jin-Kuk Chung; Lee-Sup Kim

1996-01-01

31

Modelling the Buck-Type Converter Transient Response with Pulsating Load.  

National Technical Information Service (NTIS)

The analysis and modeling of buck type converters is described. Load variations are considered like any other variable in the system. Continuous time models which enable prediction of the transient response of the converter are proposed. Practical results...

J. Arau J. Cezon F. Aldana J. Uceda

1989-01-01

32

Buck quasi-resonant converter operating at constant frequency: analysis, design and experimentation  

Microsoft Academic Search

Consideration is given to a buck zero-current-switching quasi-resonant converter (buck-PWM-ZCS-QRC) operating at constant frequency. Operation principle and design-oriented analysis are presented, with normalized design curves, design procedure, design example, simulations, and experimental results. The new topology is compared with the well-established Buck-FM-ZCS-QRC proposed by F.C. Lee (Proc. IEEE, vol.76, Apr.1988), which can be considered as a particular topology

I. Barbi; J. C. Bolacell; D. C. Martins; F. B. Libano

1989-01-01

33

Adaptive voltage regulation of PWM buck DC-DC converters using backstepping sliding mode control  

Microsoft Academic Search

This paper develops novel methodologies and techniques for voltage-regulation and implementation of a buck DC-DC converter. This type of converter is modeled as a linear averaged state-space system model with an adjustable load. The output voltage and the inductor current are employed to achieve design of an adaptive backstepping sliding mode controller for the buck DC-DC converter. Using singular perturbation

Shoei-Chuen Lin; Ching-Chih Tsai

2004-01-01

34

A Novel Control Technique for Single-Inductor Multiple-Output DC-DC Buck Converters  

Microsoft Academic Search

This paper presents the design of a single-inductor regulated multiple-output (SIMO) buck converter with interleaved switched capacitor outputs. A small signal analysis of the buck converter using state space averaging technique is carried out. A compensating network and novel control logic are designed to minimize effects of cross regulation and load transient in the three-coupled outputs. In view of the

Pradipta Patra; Susovon Samanta; A. Patra; S. Chattopadhyay

2006-01-01

35

The active-clamp couple-buck converter-a novel high efficiency voltage regulator modules  

Microsoft Academic Search

As the power demand for microprocessors increases steadily, the VRMs are required to work with a higher input voltage. The widely used synchronous buck converter will NOT work properly and efficiently for this higher input voltage because of an extremely small duty-ratio, This paper proposes a novel active-clamp couple-buck converter to solve the extremely small duty-ratio problem, Other benefits of

Peng Xu; Jia Wei; Fred C. Lee

2001-01-01

36

Speed-sensorless tracking control of a DC-motor via a double Buck-converter  

Microsoft Academic Search

This article deals with the sensor-less trajectory tracking control of a double-buck-converter\\/dc-motor combination. We simultaneously regulate, both, the output voltage of the first buck-converter and the angular velocity of the dc-motor shaft so that it tracks a pre-specified reference trajectory. The main result of our proposed control scheme is a linear time-varying controller that is based only on measurements of

J. Linares-Flores; J. Reger; H. Sira-Ramirez

2006-01-01

37

Improved control strategy on buck-boost converter fed DC motor  

Microsoft Academic Search

This paper presents comparison of the performance of neural network controller with that of conventional open loop and closed loop controllers for buck-boost converter fed dc motor based on voltage control method. It describes the use of neural networks in a control loop applied to ac-dc buck-boost converter fed dc motor. The proposed technique makes use of the learning capability

S. Ben John Stephen; T. Ruban Devaprakash

2011-01-01

38

Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters  

NASA Astrophysics Data System (ADS)

The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.

Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang

39

Accounting for Input Limitation in the Control of Buck Power Converters  

Microsoft Academic Search

We are considering the problem of controlling a DC-DC switched power converter of the Buck type. The converter involves an inherent control limitation; accordingly the control signal (duty ratio) can only take values in the interval (0, 1) . In the relevant literature, such a physical control limitation is generally not taken into account when designing the converter regulators. This

Hassan El Fadil; Fouad Giri; Fatima-Zahra Chaoui; Ouadia El Magueri

2009-01-01

40

Modelling the buck-type converter transient response with pulsating load  

NASA Astrophysics Data System (ADS)

The analysis and modeling of buck type converters is described. Load variations are considered like any other variable in the system. Continuous time models which enable prediction of the transient response of the converter are proposed. Practical results are presented to validate analytical predictions derived from the model. The proposed method can be used in other dc-dc converter topologies.

Arau, J.; Cezon, J.; Aldana, F.; Uceda, J.

1989-08-01

41

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

42

Commercial Buck Converters and Custom Coil Development for the ATLAS Inner Detector Upgrade  

SciTech Connect

A new generation of higher gain commercial buck converters built using advanced short channel CMOS processes has the potential to operate in the Atlas Inner Detector at the Super Large Hadron Collider (sLHC). This approach would inherently be more efficient than the existing practice of locating the power conversion external to the detector. The converters must operate in a large magnetic field and be able to survive both high doses of ionizing radiation and large neutron fluences. The presence of a large magnetic field necessitates the use of an air core inductor which is developed and discussed here. Noise measurements will be made to investigate the effect of the high frequency switching of the buck converter on the sensitive front end electronics. Radiation hardness of selected buck converters and mosfets will also be reported.

Dhawan, S.; Lanni, F.; Baker, O.; Chen, H.; Khanna, R.; Kierstead, J.; Lynn, D.; Musso, C.; Rescia, S.; Smith, H.; Tipton, P. and Weber, M.

2010-04-01

43

PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter  

NASA Astrophysics Data System (ADS)

The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.

Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori

44

A new resonant gate driver for switching loss reduction of high side switch in buck converter  

Microsoft Academic Search

In this paper, a new resonant gate driver circuits is proposed to reduce the switching loss of high side switch in buck converter. Hard switching causes major parts of the power loss in high side switch and limits high switching frequency application of DC-DC converter. The proposed resonant gate driver behaves more like the ideal current source driver which can

Xin Zhou; Zhigang Liang; Alex Huang

2010-01-01

45

Power budgeting of a multiple-input buck-boost converter  

Microsoft Academic Search

The use of a multiple-input buck-boost converter for budgeting power between different energy sources is discussed. It is shown mathematically that the idealized converter can accommodate arbitrary power commands for each input source while maintaining a prescribed output voltage. Power budgeting is demonstrated experimentally for a real converter under various circumstances, including a two-input (solar and line-powered) system. A closed-loop

Nicholas D. Benavides; Patrick L. Chapman

2005-01-01

46

Buck-Boost Converter for Sensorless Power Optimization of Piezoelectric Energy Harvester  

Microsoft Academic Search

This paper presents a comprehensive model for miniature vibration-powered piezoelectric generators and analyses modes of operation and control of a buck-boost converter for the purpose of tracking the generators optimal working points. The model describes the generator's power dependence with the mechanical acceleration and frequency, and helps in the definition of the load behaviour for power optimization. Electrical behaviour of

Elie Lefeuvre; David Audigier; Claude Richard; Daniel Guyomar

2007-01-01

47

Power quality based performance analysis of a dual buck converter fed four-quadrant dc drive  

Microsoft Academic Search

The phase-controlled dc drive operation is well established, however, this paper investigates the operation of the separately excited dc machine in each of the four quadrants when fed by the symmetrical multipulse modulated, improved power quality, single-phase, dual buck converter. The armature control of the dc machine with constant load torque is undertaken in both clockwise and anticlockwise directions in

A. N. Arvindan

2011-01-01

48

Non-Inverted Buck-Boost Converters with Dual Delta Sigma Modulators  

NASA Astrophysics Data System (ADS)

This paper presents a new control circuit to create high-performance non-inverted Buck-Boost converter with dual ⊿? modulations. Experimental load regulation, corresponding to load current steps of ±0.5A, is within 45mVpp, and the efficiency without synchronized rectifier is 83% at input voltage 2.5V and load current 0.8A.

Kobori, Yasunori; Kono, Masashi; Shimizu, Toshihiko; Kobayashi, Haruo

49

A novel resonant gate driver for high frequency synchronous buck converter  

Microsoft Academic Search

This paper introduces a new resonant gate driver for both the top and bottom switches of a synchronous buck converter. With a coupled inductor, this gate driver can have both small size and fewer power losses. Theoretical analysis, simulation and experimental results prove that the proposed driver is well suited to high-frequency applications

K. Yao; F. C. Lee

2001-01-01

50

A new resonant gate driver for low voltage synchronous buck converter based on topologies optimization  

Microsoft Academic Search

To reduce the high frequency gate drive losses, a new resonant gate driver is developed for low voltage synchronous buck converter based on the topologies optimizations of three candidate resonant gate drivers in this paper. The new drive circuit can reduce gate drive losses significantly. The advantages of the proposed circuit include less sensitive to track inductance, no need for

Li Liu; Yu Ma; Xiaogao Xie; Chen Zhao; Wei Yao; Zhaoming Qian

2008-01-01

51

A novel resonant gate driver for high frequency synchronous buck converters  

Microsoft Academic Search

This paper introduces a new resonant gate driver for both the top and bottom switches of a synchronous buck converter. A coupled inductor is used to reduce the size as well as to transfer energy between the top and bottom gate driving. A possible semiconductor integration approach is proposed for this resonant gate driver based on a self-adaptive control method.

Kaiwei Yao; Fred C. Lee

2002-01-01

52

First-order pseudo dead-beat current controller for buck converter  

Microsoft Academic Search

Analysis and current control using pseudo deadbeat controller (PDC) for the buck dc-dc converter is proposed in this paper. The conventional deadbeat current controller, reported in the literature, exhibit sub-harmonic oscillations and it may lead to instability in the event of parameter changes. To avoid such problems a pseudo deadbeat controller is proposed in this paper, which gives almost first

Mummadi Veerachary; Gundu Satish

2009-01-01

53

Input impedance of closed-loop PWM buck-boost DC-DC converter for CCM  

Microsoft Academic Search

The small-signal closed-loop impedance of the PWM buck-boost DC-DC converter is derived for continuous conduction mode (CCM), taking into account all parasitic resistances. The plots of the closed-loop input impedance are shown versus frequency for three values of the duty cycle

M. K. Kazimierczuk

1995-01-01

54

Large signal design of a buck converter for high power dc\\/ac conversion  

Microsoft Academic Search

Parameters defining the stable operation of the closed loop system in buck converter design considerations are discussed. Such parameters as poles and transmittance gains are examined, the study is aimed at determining suitable corrective networks giving the smallest modulus of the characteristic equation roots, and at determining parameter tolerances which allow acceptable performances compatible with stability criteria. It is found

J. C. Marpinard; J. Jalade; M. Valentin

1981-01-01

55

Speed control of a dc series motor using Buck-Boost converter  

Microsoft Academic Search

This paper presents a Buck-Boost converter using a MOSFET as a switch fed a dc series motor. The characteristics for step - up and down of the output voltage are studied. It is found that this system posses a good operation performance with a minimum ripple in the output of the motor current and voltage. The mathematical models describing both

Nabil T. Tweig

2006-01-01

56

A novel method to achieve zero-voltage regulation in buck converter  

Microsoft Academic Search

The function control law for a buck converter is derived to achieve zero voltage regulation of the output voltage. A new method to retrieve the low frequency component of the inductor voltage is proposed and analyzed. The stability of the closed loop system using a proportional and differential controller is analyzed. The effect of the supply voltage and load current

Yan-Fei Liu; Paresh C. Sen

1995-01-01

57

Closed-Loop Input Impedance of PWM Buck-Derived DC-DC Converters  

Microsoft Academic Search

The small-signal closed-loop input impedance is derived for the PWM buck DC-DC converter operated in continuous conduction mode (CCM), taking into account all parasitic resistances. The plots of the closed-loop input impedance are shown versus frequency for four values of the equivalent series resistance of the capacitor

Marian K. Kazimierczuk; Robert Cravens II; Alberto Reatti

1994-01-01

58

A new approach for high efficiency buck-boost DC\\/DC converters using series compensation  

Microsoft Academic Search

This paper proposes a new buck-boost DC\\/DC converters, which is connected in series to the power supply. The proposed circuit provides only differential voltage between the input voltage and the output voltage command. The power rating of a conventional circuit is dominated by the input voltage or the output voltage. In contrast, the voltage rating of the proposed circuit requires

Jun-ichi Itoh; Takashi Fujii

2008-01-01

59

Stability analysis of a non-inverting synchronous buck-boost power converter for a solar power management system  

Microsoft Academic Search

This paper presents the stability analysis of a non-inverting synchronous buck-boost DC\\/DC power converter for a solar power management system. The system can operate in buck, buck-boost or boost mode according to the condition of the supply voltage. The variation of the supply voltage arises from the rapid changes of the atmospheric condition or sunlight incident angle. The stability margins

Jaw-Kuen Shiau; Chun-Jen Cheng; Ching-En Tseng

2008-01-01

60

Two-Loop Controlled Buck–SEPIC Converter for Input Source Power Management  

Microsoft Academic Search

A two-loop digital control strategy is proposed for load distribution on a two-input integrated buck–SEPIC converter-based dc–dc power conversion system. The proposed control strategy involves two decoupled control loops: one for low-voltage source (LVS) current control and the other for dc load voltage regulation. A discrete-time model of the proposed converter is established, and then, the relative gain array theory

Mummadi Veerachary

2012-01-01

61

A new low-stress buck-boost converter for universal-input PPC applications  

Microsoft Academic Search

In converters for power-factor-correction (PFC), universal-input capability (ability to operate from any AC line voltage, world-wide) comes with a heavy price in terms of component stresses and losses, size of components, and restrictions on the output DC voltage. A new two-switch topology is proposed to offer very significant performance improvements over the single-switch buck-boost converters (including flyback, SEPIC, and Cuk

Jingquan Chen; Dragan MaksimoviC; Robert Erickson

2001-01-01

62

Low temperature performance of a closed loop three level buck converter  

Microsoft Academic Search

Low-temperature operation of a closed loop three level buck DC-to-DC power converter with charge pump controller has been experimentally investigated. The power converter system has been designed and built with standard commercially available components. Performance characteristics such as efficiency and regulation are studied for different temperatures from 25°C down to -184°C. CMOSICs, MOSFET switches and ultrafast diodes prove to be

Fausto F. Perez-Guerrero; K. Venkatesan; B. Ray; Richard L. Patterson

1999-01-01

63

Zero-voltage-switching buck-flyback isolated DC-DC converter with synchronous rectification  

Microsoft Academic Search

This paper presents a zero-voltage-switching (ZVS) buck-flyback isolated DC-DC converter with two isolated outputs on the primary side and secondary side respectively, wherein primary-side feedback control is used. The primary output is tightly regulated while achieving rough regulation for the secondary output. Since no control isolation is needed, the cost and complexity are reduced as compared with conventional flyback converters

Liangbin Yao; Hong Mao; Jun Liu; Issa Batarseh

2006-01-01

64

A new isolated bidirectional buck-boost PWM converter  

Microsoft Academic Search

In this paper, a new isolated dc-dc bidirectional converter is introduced. This converter consists of flyback and forward transformers and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states and controlled by PWM signal. Therefore implementation of control circuits is

M. Delshad; H. Farzanehfard

2010-01-01

65

Advanced buck converter power supply ABCPS for APT  

SciTech Connect

The United States Department of Energy (DOE) is planning to fabricate an Accelerator for the Production of Tritium (APT) at their Savannah River Site, to provide Tritium for national defense. The 1700 million electron volt (MeV) proton beam accelerator will be powered by radio frequency (RF) klystrons. A direct current (DC) power supply is required for each of the approximately two hundred and fifty 1-megawatt (MW) continuous wave klystrons in the RF power system. The requirements are that the power supply meet output performance specifications, provide fault protection for the klystron, have high efficiency, high reliability, good maintainability, and be readily manufacturable. As the power supplies are one of the largest cost elements in the accelerator, a technology review was made to determine the most economical approach to satisfy the requirements. A switch-mode power supply employing a buck-regulator was identified as being potentially the lowest cost approach. As the switch represents a certain development risk, a small-scale prototype has been constructed for evaluation, and has resulted in the decision to fabricate a full-scale prototype power supply. A description of the hardware will be presented.

Street, R.; Overett, T.; Bowles, E. [General Atomics, San Diego, CA (United States)

1998-12-31

66

A current-mode DC—DC buck converter with adaptive zero compensation  

NASA Astrophysics Data System (ADS)

To achieve fast transient response for a DC—DC buck converter, an adaptive zero compensation circuit is presented. The compensation resistance is dynamically adjusted according to the different output load conditions, and achieves an adequate system phase margin under the different conditions. An improved capacitor multiplier circuit is adopted to realize the minimized compensation capacitance size. In addition, analysis of the small-signal model shows the correctness of the mechanism of the proposed adaptive zero compensation technique. A current-mode DC—DC buck converter with the proposed structure has been implemented in a 0.35 ?m CMOS process, and the die size is only 800 × 1040 ?m2. The experimental results show that the transient undershoot/overshoot voltage and the recovery times do not exceed 40 mV and 30 ?s for a load current variation from 100 mA to 1 A.

Ling, Yang; Guoding, Dai; Chongwei, Xu; Yuezhi, Liu

2013-08-01

67

Linearization of the control-to-output transfer function for a PWM buck-boost converter  

Microsoft Academic Search

A new method for linearizing the control-to-output transfer function of a PWM buck-boost converter is presented in this paper. The DC and the small-signal characteristics are derived. A compensating signal relating to the inverse of the nonlinear term appeared in the control-to-output transfer function is produced from the duty ratio, and then fed into the feedback loop. Experimental results show

Yu-Kang Lo; Shang-Chin Yen; Jan-Ming Wang

2004-01-01

68

Automotive DC-DC bidirectional converter made with many interleaved buck stages  

Microsoft Academic Search

Interleaving technique is used in some applications due to its advantages regarding filter reduction, dynamic response, and power management. In dual battery system vehicles, the bidirectional dc-dc converter takes advantage of this technique using three-to-five paralleled buck stages. In this paper, we propose the use of a much higher number of phases in parallel together with digital control. It will

Oscar García; Pablo Zumel; A. de Castro; A. Cobos

2006-01-01

69

AC\\/AC Buck Converter Instantaneous Value Control Modeling, System Analyzing and Designing  

Microsoft Academic Search

Close-loop control to the power electronics transformer (PET) was not well solved still now, we studied the basic topology of PET-AC\\/AC buck converter, built its small-signal model, analyzed its frequency characteristic, and pointed out that: under general inductive load condition, the open-loop model is an approximate second-order undamped oscillation system, it is marginally stable and output voltage oscillation can be

Ma Huasheng; Zhang Bo; Zheng Jianchao; Zhao Liang

2005-01-01

70

Design of closed-loop buck-boost converter for LED driver circuit  

Microsoft Academic Search

This paper develops a light emitting diode (LED) driver circuit with a buck-boost converter. The forward bias of the LED used was 3.1V~4.3V, and the forward current was 0.7A. Twelve 3W white-light LEDs were driven in series in the proposed circuit. Each LED was operated at 4V and 0.6A using ac 110V that was rectified by a bridge rectifier. It

Chi-Jen Huang; Ying-Chun Chuang; Yu-Lung Ke

2011-01-01

71

PI controller design via singular perturbation technique for AC-AC buck-boost converter  

Microsoft Academic Search

The problem of AC voltage regulation based on AC-AC buck-boost converter is discussed in presence of resistor load variations and voltage source variations as well. The design methodology of cascaded proportional-integral (PI) controller via singular perturbation technique is presented where two-time-scale motions are artificially induced in the closed-loop system. Stability conditions imposed on the fast and slow modes and sufficiently

V. D. Yurkevich; G. S. Zinoviev

2008-01-01

72

Optimal control of a three level DC to DC buck converter  

Microsoft Academic Search

The present work deals with the design and development of an optimal closed-loop three level DC-to-DC buck converter. The effect of phase shift on efficiency and voltage across the energy transfer capacitor of the power circuit has been investigated. A charge-pump controller has been added to a closed-loop system and the performance has been experimentally studied. Since all studies indicate

Fausto F. Perez-Guerrero; K. Venkatesan; Richard L. Patterson

1999-01-01

73

Closed-loop analysis and control of a non-inverting buck–boost converter  

Microsoft Academic Search

In this article, a cascade controller is designed and analysed for a non-inverting buck–boost converter. The fast inner current loop uses sliding mode control. The slow outer voltage loop uses the proportional–integral (PI) control. Stability analysis and selection of PI gains are based on the nonlinear closed-loop error dynamics incorporating both the inner and outer loop controllers. The closed-loop system

Zengshi Chen; Jiangang Hu; Wenzhong Gao

2010-01-01

74

Proximate Time-Optimal Digital Control for Synchronous Buck DC–DC Converters  

Microsoft Academic Search

This paper introduces an approach to near time-optimal control for synchronous buck dc-dc converters. The proposed proximate time-optimal digital (PTOD) controller is a combination of a constant-frequency pulsewidth modulation (PWM) controller employing a linear PID compensator close to a reference point, and a linear or nonlinear switching surface controller (SSC) away from the reference, together with smooth transitions between the

Vahid Yousefzadeh; Amir Babazadeh; Bhaskar Ramachandran; Eduard Alarcon; Lucy Pao; Dragan Maksimovic

2008-01-01

75

An active current-sensing constant-frequency HCC buck converter using phase-frequency-locked techniques.  

PubMed

A hysteresis-current-controlled (HCC) buck converter with active current-sensing and phase-frequencylocked techniques is presented in this paper. The proposed active current-sensing technique can not only consume less power than previous techniques, but also fully sense the inductor current. Although the buck converter is HCC, the switching frequency can be constant due to the devised phase-frequency-locked technique. The proposed converter has been designed and implemented with TSMC 0.35 microm DPQM CMOS processes. It is shown in the experimental results that the HCC buck converter features the following characteristics: 1) up to 800 mA of load current, 2) wide input and output voltage range, 3) high power efficiency, and 4) constant-frequency operation. PMID:18467220

Chen, Jiann-Jong

2008-04-01

76

Modeling and dynamics analysis of the fractional-order Buck—Boost converter in continuous conduction mode  

NASA Astrophysics Data System (ADS)

In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck—Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck—Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as ? and ? vary. At the same time, the simulation results show that the converter goes through different routes to chaos.

Yang, Ning-Ning; Liu, Chong-Xin; Wu, Chao-Jun

2012-08-01

77

Large signal design of a buck converter for high power dc/ac conversion  

NASA Astrophysics Data System (ADS)

Parameters defining the stable operation of the closed loop system in buck converter design considerations are discussed. Such parameters as poles and transmittance gains are examined, the study is aimed at determining suitable corrective networks giving the smallest modulus of the characteristic equation roots, and at determining parameter tolerances which allow acceptable performances compatible with stability criteria. It is found that the transfer function compensating network should be placed in parallel with the initial control loop, and to satisfy stability requirements, all the z poles in a closed loop should be zero.

Marpinard, J. C.; Jalade, J.; Valentin, M.

78

Comparison of the Kharitonov method with others for the robust stability analysis of a PWM buck converter  

Microsoft Academic Search

An investigation of the robust stability of a pulse-width modulated buck DC-DC converter is carried out, considering the uncertainty in the components used for the converter circuit. An alternative method which is less conservative than the Kharitonov Theorem (1978) approach is used to find robust stability bounds and to show that the compensated system of the device remains stable when

A. S. M. Nazirul; I. Shaheen; L. R. Pujara; M. K. Kazimierczuk

1997-01-01

79

Stability analysis of two-cell Buck converter driven DC motor with a discrete-time closed loop  

Microsoft Academic Search

In this paper we deal with the dynamical behavior modeling, design and simulation of a two-cell DC-DC Buck converter driven DC motor. The angular velocity of the motor is controlled with a feedback loop through a Digital Pulse Width Modulation (DPWM). The stress of the switches of the converter are also balanced between the cells. Discrete time approach is used

A. El Aroudi; J. Pelaez; M. Feki; B. G. M. Robert

2009-01-01

80

Design of high efficiency dual-mode buck DC-DC converter  

NASA Astrophysics Data System (ADS)

A buck DC—DC switching regulator with high efficiency is implemented by automatically altering the modulation mode according to load current, and it can operate with an input range of 4.5 to 30 V. At light load current, the converter operates in skip mode. The converter enters PWM mode operation with increasing load current. It reduces the switching loss at light load and standby state, which results in prolonging battery lifetime and stand-by time. Meanwhile, externally adjustable soft-start minimizes the inrush supply current and avoids the overshoot of output voltage at initial startup. The regulator is fabricated by a 0.6 ?m CDMOS process. The test results show that, under the condition of 3.3 V output, the efficiency is up to 64% at 5 mA and the maximum efficiency is 95.5%.

Xinquan, Lai; Huali, Zeng; Qiang, Ye; Huisen, He; Shasha, Zhang; Yuqing, Sun

2010-11-01

81

Grid Interaction Operation of a Telecommunications Power System With a Novel Topology for Multiple-Input Buck-Boost Converter  

Microsoft Academic Search

Typically, telecom power systems are connected to the grid and diesel generator. This paper represents a new telecom power system using local microsources (fuel cell and microturbine). Some benefits of this system are effectively eliminating batteries, diesel generator, and automatic transfer switch. In this study, a new multiple input buck-boost converter is utilized as an interface between the microsources and

Omer Caglar Onar; O. H. A. Shirazi; A. Khaligh

2010-01-01

82

Fast-Scale and Slow-Scale Subharmonic Oscillation of Valley Current-Mode Controlled Buck Converter  

NASA Astrophysics Data System (ADS)

A valley current-mode (VCM) controlled buck converter with current source load (CSI) has complex phenomena of fast-scale and slow-scale subharmonic oscillations. The piecewise smooth switching model of the VCM controlled buck converter with CSI is established. It is found that attractive regions of fast-scale and slow-scale subharmonic oscillations exist in the bifurcation diagram, and two tori exist in the corresponding Poincaré mapping. The research results by time-domain simulation indicate that U-type subharmonic oscillation (SO) constituted by SO and frequency-reduced subharmonic oscillation (FSO) exists in inductor current, and sine-type SO constituted by fast scale and low scale exists in output voltage respectively. Experimental results are given to verify the analysis and simulation results.

Zhou, Guo-Hua; Xu, Jian-Ping; Bao, Bo-Cheng; Zhang, Fei; Liu, Xue-Shan

2010-09-01

83

Closed-loop regulated power supply for ozone generation based on buck converter and current-fed push-pull resonant inverter  

Microsoft Academic Search

In this paper the design, implementation and experimental results of a high-voltage power supply for ozone generation are presented. The power stage is formed by a buck converter plus a current-fed parallel-resonant push-pull inverter. The buck converter is used to both regulate the output power against the line voltage variation, and to control the power delivered to the ozone generator

J. M. Alonso; C. Ordiz; D. Gacio; J. Ribas; A. J. Calleja

2009-01-01

84

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

85

Grazing, skipping and sliding: Analysis of the non-smooth dynamics of the DC/DC buck converter  

NASA Astrophysics Data System (ADS)

This paper provides an analytical insight into the observed nonlinear behaviour of a simple widely used power electronic circuit (the buck converter) and draws parallels with a wider class of piecewise-smooth systems. After introducing the buck converter model and background, the most fascinating features of its dynamical behaviour are reviewed. So-called grazing and sliding solutions are discussed and their role in determining many of the buck converter's dynamical oddities is demonstrated. In particular, a local map is studied which explains how grazing bifurcations cause sharp turning points in the bifurcation diagram of periodic orbits. Moreover, these orbits are shown to accumulate onto a sliding trajectory through a `spiralling' impact adding scenario. The structure of such a diagram is derived analytically and is shown to be closely related to the analysis of homoclinic bifurcations. The results are shown to match perfectly with numerical simulations. The sudden jump to large-scale chaos and the fingered structure of the resulting attractor are also explained.

di Bernardo, Mario; Budd, Chris; Champneys, Alan

1998-07-01

86

A fast novel soft-start circuit for peak current-mode DC—DC buck converters  

NASA Astrophysics Data System (ADS)

A fully integrated soft-start circuit for DC—DC buck converters is presented. The proposed high speed soft-start circuit is made of two sections: an overshoot suppression circuit and an inrush current suppression circuit. The overshoot suppression circuit is presented to control the input of the error amplifier to make output voltage limit increase in steps without using an external capacitor. A variable clock signal is adopted in the inrush current suppression circuit to increase the duty cycle of the system and suppress the inrush current. The DC—DC converter with the proposed soft-start circuit has been fabricated with a standard 0.13 ?m CMOS process. Experimental results show that the proposed high speed soft-start circuit has achieved less than 50 ?s start-up time. The inductor current and the output voltage increase smoothly over the whole load range.

Jie, Li; Miao, Yang; Weifeng, Sun; Xiaoxia, Lu; Shen, Xu; Shengli, Lu

2013-02-01

87

Realization of a Single Phase Matrix Converter with Reduce switch count as a buck\\/boost rectifier with close loop control  

Microsoft Academic Search

This Paper focused on Buck\\/Boost Rectification by Single Phase Matrix Converter with fewer numbers of switches. The conventional matrix converter consists of 4 bidirectional switches, i.e. 8 set of IGBT\\/MOSFET with anti parallel diodes. In this proposed matrix converter, only six switches are used. The switch commutation arrangements are also carried out in this work. The gate pulses to the

R. M. Anusuya; R. Saravanakumar

2012-01-01

88

A Universal-Input Single-Stage High-Power-Factor Power Supply for HB-LEDs Based on Integrated Buck-Flyback Converter  

Microsoft Academic Search

Due to the high rise in luminous efficiency that HB-LEDs have experienced in the last recent years, many new applications have been researched. In this paper, a streetlight LED application will be covered, using the integrated buck-flyback converter developed in previous works, which performs power factor correction (PFC) from a universal AC source, as well as a control loop using

D. Gacio; J. M. Alonso; A. J. Calleja; J. Garcia; M. Rico-Secades

2009-01-01

89

Robust control of parallel DC-DC buck converters by combining integral-variable-structure and multiple-sliding-surface control schemes  

Microsoft Academic Search

We develop a robust controller for parallel DC-DC buck converters by combining the concepts of integral-variable-structure and multiple-sliding-surface control. The advantages of the scheme are its simplicity in design, good dynamic response, robustness, ability to nullify the bus-voltage error and the error between the load currents of the converter modules under steady-state conditions, and ability to reduce the impact of

Sudip K. Mazumder; Ali H. Nayfeh; A. Borojevic

2002-01-01

90

A Universal-Input Single-Stag2e High-Power-Factor Power Supply for HB-LEDs Based on Integrated Buck–Flyback Converter  

Microsoft Academic Search

Due to the high rise in luminous efficiency that high- brightness light-emitting diodes (HB-LEDs) have experienced in recent years, many new applications have been researched. This paper covers a streetlight LED application using the offline in- tegrated buck-flyback converter (IBFC) developed in previous works. In this application, the converter is used to provide power- factor correction from a universal ac

David Gacio; J. Marcos Alonso; Antonio J. Calleja; Jorge Garcia; Manuel Rico-Secades

2011-01-01

91

A new zero voltage switching buck-boost bidirectional DC_DC converter  

Microsoft Academic Search

In this paper a new zero voltage switching bidirectional dc-dc converter is introduced. This converter consists of flyback and forward transformers and only one main switch in primary side and one main switch in secondary side of transformers. Auxiliary circuits in this converter consist of a switch and one clamp capacitor. These circuits not only absorb spikes across the switches

Majid Delshad; M. Mahdavi

2010-01-01

92

A 1500 mA, 10 MHz on-time controlled buck converter with ripple compensation and efficiency optimization  

NASA Astrophysics Data System (ADS)

A 1500 mA, 10 MHz self-adaptive on-time (SOT) controlled buck DC—DC converter is presented. Both a low-cost ripple compensation scheme (RCS) and a self-adaptive on-time generator (SAOTG) are proposed to solve the system stability and frequency variation problem. Meanwhile a self-adaptive power transistor sizing (SAPTS) technique is used to optimize the efficiency especially with a heavy load. The circuit is implemented in a 2P4M 0.35 ?m CMOS process. A small external inductor of 0.47 ?H and a capacitor of 4.7 ?F are used to lower the cost of the converter and keep the output ripple to less than 10 mV. The measurement results show that the overshoot of the load transient response is 8 mV @ 200 mA step and the dynamic voltage scaling (DVS) performance is a rise of 16 ?s/V and a fall of 20 ?s/V. With a SAPTS technique and PFM control, the efficiency is maintained at more than 81% for a load range of 20 to 1500 mA and the peak efficiency reaches 88.43%.

Jiale, Yu; Danzhu, Lü; Zhiliang, Hong

2012-01-01

93

Optimizing LQR and pole placement to control buck converter by genetic algorithm  

Microsoft Academic Search

Power supplies normally provide a constant output voltage. In most of the applications a DC-DC converter is controlled by a voltage mode or a current mode controller. The DC converters are employed to feed electric vehicles, telephone sets and civil invertors, or for induction motors and frequency control. In this regard, optimal exploitation of DC transforms by classical controllers has

M. B. Poodeh; S. Eshtehardiha; A. Kiyoumarsi; M. Ataei

2007-01-01

94

Exact Analytic Treatment Of The Buck-boost DC\\/DC Converter  

Microsoft Academic Search

In recent years the requirements for reduction of costs and thereby of the number of components and protection circuits in DC\\/DC converters, as parts of the overall power supply systems, have increased significantly. The large number of new circuit topologies with optimized circuit parameters has been proposed and in some cases even productified. All this has increased the interest for

Nils Dalarsson

1997-01-01

95

A type-2 fuzzy logic controller design for buck and boost DC–DC converters  

Microsoft Academic Search

Conventional (type-1) fuzzy logic controllers have been commonly used in various power converter applications. Generally,\\u000a in these controllers, the experience and knowledge of human experts are needed to decide parameters associated with the rule\\u000a base and membership functions. The rule base and the membership function parameters may often mean different things to different\\u000a experts. This may cause rule uncertainty problems.

Ismail Atacak; Omer Faruk Bay

96

Hysteresis and delta modulation control of buck converters with sensorless current mode  

Microsoft Academic Search

Sensorless current mode (SCM) is a control formulation for dc-dc converters that results in voltage-source characteristics, excellent open-loop tracking, and near-ideal source rejection. Hysteresis and delta modulation are well-known, easy-to-construct large-signal methods for switched systems. Combining either large-signal method with SCM creates a controller that is simpler and more robust than a pulse-width modulation (PWM) based controller. These approaches can

Mahdi Shaneh; Khalil Rahimi; Majid Pakdel

2008-01-01

97

A Current-Mode Buck DC-DC Converter with Frequency Characteristics Independent of Input and Output Voltages Using a Quadratic Compensation Slope  

NASA Astrophysics Data System (ADS)

By using a quadratic compensation slope, a CMOS current-mode buck DC-DC converter with constant frequency characteristics over wide input and output voltage ranges has been developed. The use of a quadratic slope instead of a conventional linear slope makes both the damping factor in the transfer function and the frequency bandwidth of the current feedback loop independent of the converter's output voltage settings. When the coefficient of the quadratic slope is chosen to be dependent on the input voltage settings, the damping factor in the transfer function and the frequency bandwidth of the current feedback loop both become independent of the input voltage settings. Thus, both the input and output voltage dependences in the current feedback loop are eliminated, the frequency characteristics become constant, and the frequency bandwidth is maximized. To verify the effectiveness of a quadratic compensation slope with a coefficient that is dependent on the input voltage in a buck DC-DC converter, we fabricated a test chip using a 0.18µm high-voltage CMOS process. The evaluation results show that the frequency characteristics of both the total feedback loop and the current feedback loop are constant even when the input and output voltages are changed from 2.5V to 7V and from 0.5V to 5.6V, respectively, using a 3MHz clock.

Sai, Toru; Sugimoto, Yasuhiro

98

Piecewise Broken Line Approximation Method implementation in stability analysis of bidirectional Buck\\/Boost converters cascaded system  

Microsoft Academic Search

Closed-loop input and output impedance of converters are nonlinear functions and with too many converter parameters, which causes it very difficult to do quantitative analysis of converters cascaded system stability with Middlebrook impedance criterion. In this paper, piecewise broken line approximation method (PBLAM) is proposed to simplify the closed-loop output and input impedances of converters. A cascaded system with two

Hao Wang; Jinjun Liu; Dan Hou

2009-01-01

99

Chip-Package Co-modeling & Verification of Noise Coupling & Generation in CMOS DC\\/DC Buck Converter  

Microsoft Academic Search

DC\\/DC Converters are now an essential part in a system due to the various needs of supply voltage that is necessary for different circuits in the system. However, there are many papers which have dealt for efficiency or for a novel structure that would be customized to the specific design, but few dealt with the noise characteristics of DC\\/DC converters

Taigon Song; Jiseong Kim; Junso Pak; Joungho Kim

2009-01-01

100

Study of bi-directional buck-boost converter topologies for application in electrical vehicle motor drives  

Microsoft Academic Search

The use of a bi-directional DC-DC converter in motor drives devoted to EVs allows a suitable control of both motoring and regenerative braking operations. In particular, during motoring operations of a battery-fed DC motor drive, a DC-DC converter is to be used to adjust the motor current in order to follow the torque reference signal. On the other hand, a

F. Caricchi; F. Crescimbini; F. G. Capponi; L. Solero

1998-01-01

101

A high power density 1.75 mm2 fully integrated closed-loop buck converter with varactor control scheme  

Microsoft Academic Search

A high power density fully integrated DC-DC power converter is realized with improved quality factor on-chip inductor and high frequency switching. The power converter output voltage change is non-linear with Pulse Width Modulation (PWM) at high frequencies, hence a new control scheme with a varactor to adjust output voltage has been proposed in the paper. Detailed analysis of the design

Prabal Upadhyaya; Nan Shi; Sean Bradburn; Herbert L. Hess

2008-01-01

102

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

103

Robust feedforward compensation scheme with AC booster for high frequency low voltage buck DC–DC converters  

Microsoft Academic Search

Today and in the future, high frequency low voltage DC–DC converters are an effective power-management solution for fast transient\\u000a response and small profile in portable electronic systems. This paper presents a robust feedforward compensation scheme with\\u000a AC booster. An ac amplifier is added in parallel with the main path to compensate the high-frequency gain reduction, which\\u000a improves gain-bandwidth (GBW) product

Chunming Zhang; Zhibiao Shao

104

Analysis and experimental study of the buck, boost and buck-boost inverters  

Microsoft Academic Search

In this paper, the analysis and experimental study of three kinds of inverters are presented, beginning with the traditional full bridge buck inverter, followed by two different inverter approaches, the boost and buck boost ones. This last two converters have the property of produce an output voltage higher or lower than the input voltage additionally to its inversion capability, which

N. Vazquez; J. Almazan; J. Alvarez; C. Aguilar; J. Arau

1999-01-01

105

A comparison between the buck, boost and buck-boost inverters  

Microsoft Academic Search

In this paper, an analysis and experimental study of three kinds of inverters are presented. Beginning with the traditional full-bridge buck inverter; followed by two different inverter approaches, the boost and buck boost ones. These last two converters have the property of producing an output voltage higher or lower than the input voltage additionally to its inversion capability, which is

J. Almazan; N. Vazquez; C. Hernandez; J. Alvarez; J. Arau

2000-01-01

106

Bucks Harbor Study, Machiasport, Maine.  

National Technical Information Service (NTIS)

The Buck Harbor study has investigated the history and existing conditions at Bucks Harbor, located at Machiasport, Maine. The study has addressed and evaluated several options for the future development of Bucks Harbor. One of the key factors recognized ...

1986-01-01

107

Ram and buck management.  

PubMed

Careful management is necessary to ensure the reproductive success in any small ruminant farm and to maximise the productive longevity of rams and bucks. Rams and bucks are frequently overlooked outside of the breeding period, but year-round attention to nutrition, parasite control and general disease control is important in keeping them healthy and sound for breeding. Pre-mating soundness examinations are an inexpensive and relatively easy way to assess the potential ability of a ram or buck to perform during the breeding period and should be incorporated annually into the management of any flock. During the breeding period, careful thought should be given to the appropriate use of males, and the effectiveness of mating should be monitored. PMID:22326610

Ridler, A L; Smith, S L; West, D M

2012-01-25

108

Power converters and amplifiers (review of \\  

Microsoft Academic Search

This book is a comprehensive textbook in the areas of electrical, electronics, and telecommunications engineering. It consists of 17 chapters and two appendices. Some of the topics covered include: buck PWM DC-DC converters; boost PWM DC-DC converters; buck-boost-PWM DC-DC converters; half-bridge and full-bridge converters; push-pull PWM DC-DC converters; open-loop small-signal characteristics of boost converters for CCM; current-mode control of boost

Marian Kazmierkowski

2009-01-01

109

Buck-boost impedance networks  

Microsoft Academic Search

Most inverters designed to date can only perform either voltage-buck or boost operation with buck-boost mode usually attained by introducing additional active semiconductor devices and passive components to the inverters. Although effective, adding active switches will complicate the inverter control, and push up the overall system costs. Therefore, alternative topological solutions are of interest, and should preferably be implemented using

Poh Chiang Loh; Feng Gao; Frede Blaabjerg; Ai Lian Goh

2007-01-01

110

Converter  

NSDL National Science Digital Library

In this activity, students enter in a fraction and the applet calculates the decimal representation of the fraction and vice versa. This activity allows students to explore converting fractions from decimals and from decimals to fractions. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

111

Bidirectional control of inverse KY converter  

Microsoft Academic Search

An inverse KY converter, derived from the KY converter, is proposed herein. And such a converter can be used as a bidirectional converter, whose operating modes are classified into two modes. One is the buck mode and the other is the boost mode. This converter can operate stably between these two modes. In this paper, the detailed illustration of the

K. I. Hwu; Y. H. Chen

2009-01-01

112

Pearl S. Buck and Phenylketonuria (PKU)  

Microsoft Academic Search

In 1921, Pearl S. Buck gave birth to a daughter, Carol, who became severely retarded and was eventually institutionalized at the Vineland Training School in New Jersey. To help pay for her daughter’s care, Buck wrote The Good Earth in 1931, and then other novels and biographies about her life in China, for which she was awarded the Nobel and

Stanley Finger; Shawn E. Christ

2004-01-01

113

Multiphase coupled converter models dedicated to transient response and output voltage regulation studies  

Microsoft Academic Search

In order to study transient response and output voltage regulation in multiphase coupled buck converter, it is proposed two models of interleaved coupled buck converter. These two models provide accurate current and voltage waveforms for any value of duty cycle. In the first part, the two proposed models are described in details. In the second part, it is shown the

Nadia Bouhalli; Marc Cousineau; Emmanuel Sarraute; Thierry Meynard

2008-01-01

114

A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation  

SciTech Connect

A new control algorithm for the three-phase buck rectifier with an input filter is developed. The algorithm employs a separate control loop for compensation of the input current displacement factor in steady-state, in addition to the standard output voltage regulation loop. The algorithm allows separate design of the input filter and of closed-loop output voltage control. The design procedure is explained and illustrated with an example. The algorithm is verified experimentally on a 1 kW, 100 kHz, three-phase isolated buck converter.

Hiti, S.; Vlatkovic, V.; Borojevic, D.; Lee, F.C.Y. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

1994-03-01

115

A DC-DC digitally controlled buck regulator utilizing first-order ?? frequency discriminators  

Microsoft Academic Search

This paper describes a novel feedback digitization architecture for a digitally controlled PWM DC-DC buck converter. A combination of a VCO followed by an all digital first-order Sigma-Delta frequency discriminators (SDFD) is used as a feedback analog-to-digital converter (ADC). The output of the discriminator is decimated to obtain a higher resolution depending on the output ripple specifications. A block diagram

Hani Ahmad; Bertan Bakkaloglu

2008-01-01

116

A Hamiltonian viewpoint in the modeling of switching power converters  

Microsoft Academic Search

In this paper we show how, using the Hamiltonian formalism, we can systematically derive mathematical models that describe the behaviour of a large class of switching power converters, including the “Boost”, “Buck”, “Buck-Boost”, “?uk” and “Flyback” converters. We follow the approach proposed by van der Schaft and Maschke and extract from the basic (energy-conserving) LC–circuit the remaining elements, i.e., resistors,

Gerardo Escobar; Arjan J. van der Schaft; Romeo Ortega

1999-01-01

117

Buck-boost switched-capacitor DC-DC voltage regulator using delta-sigma control loop  

Microsoft Academic Search

This paper presents a delta-sigma control loop for a buck-boost DC-DC converter with fractional gains. The charge pump used to convert the input voltage acts as a D\\/A converter in the loop, and its output ripple is frequency shaped by the loop, which also provides the pulse frequency modulation needed for the conversion. Simulation results show that the delta-sigma loop

A. Rao; W. Mcintyre; J. Parry; Un-ku Moon; Gabor C. Temes

2002-01-01

118

Application of EXCEL for analyzing DC\\/DC converters  

Microsoft Academic Search

EXCEL is an often used and easily accessible calculation and drawing tool. The application for analyzing converters is therefore obvious. A special step-down converter is used to explain and to show the efficiency and usefulness of this tool for technical applications. The use of tapped inductors in the classical buck converter leads to high step-down ratios overcoming the extreme duty

Peter H. WURM; Felix A. HIMMELSTOSS

1998-01-01

119

Educational platform for closed-loop simulation of power converters  

Microsoft Academic Search

This paper presents a study of the Buck converter with closed-loop control and a Matlab simulation of this converter model. The closed-loop allows to regulated the output voltage for input voltage and load variation. The Matlab model is composed of the differential equations that define the implemented system. In order to implemented the simulation platform, the converter operation was described

A. Taut; Serban Lungu; O. Pop

2009-01-01

120

A 1MHz High-Efficiency 12-V Buck Voltage Regulator With a New Current-Source Gate Driver  

Microsoft Academic Search

This paper proposes a new current-source gate drive circuit for a synchronous buck converter. The proposed driver can drive two MOSFETs independently with different drive currents for optimal design. For the control MOSFET, the optimal design involves a tradeoff between switching loss reduction and drive circuit loss; while for the synchronous-rectifier MOSFET, the optimal design involves a tradeoff between body

Zhiliang Zhang; Wilson Eberle; Ping Lin; Yan-Fei Liu; Paresh C. Sen

2008-01-01

121

Modulation of three-level Z-source indirect matrix converter  

Microsoft Academic Search

This paper proposes an actively controlled three-level Z-source matrix converter with capability of performing output voltage buck-boost, and producing sinusoidal input-output quantities. The converter is in principle realized by inserting a Z-source impedance network to the dc-link of the otherwise voltage-buck only indirect matrix converter (IMC), formed by cascading a front-end current source rectifier and a rear-end three-level inverter together.

Xiong Liu; Poh Chiang Loh; Fang Zheng Peng; Peng Wang; Feng Gao

2010-01-01

122

Design-Oriented Analysis and Performance Evaluation of Buck PFC Front End  

Microsoft Academic Search

In universal-line ac\\/dc converters that require power factor correction (PFC), maintaining a high efficiency across the entire line and load ranges poses a major challenge. Typically, a boost PFC front end exhibits 1%-3% lower efficiency at 100-V line compared to that at 230-V line. It is shown in this paper that a buck PFC front end with an output voltage

Laszlo Huber; Liu Gang; M. M. Jovanovic

2010-01-01

123

Delta-modulated buck-type PWM converter  

Microsoft Academic Search

A delta-modulated, current-source, three-phase pulsewidth modulation (PWM) rectifier is described. The rectifier is intended to be used in conjunction with controlled current inverters. An outer proportional feedback loop regulates the unidirectional output current flowing through the DC link. An inner feedback loop maintains near sinusoidal waveform currents at unity or leading power factor from the utility power supply. The inner

Bakari M. M. Mwinyiwiwa; Patricia M. Birks; Boon-Teck Ooi

1992-01-01

124

Low-Frequency Characterization of Switched dc-dc Converters  

Microsoft Academic Search

Averaging techniques are developed to represent buck, boost, and buck-boost types of switched dc-dc converters by approximate continuous models. Simple analytical expressions in terms of the circuit components are derived for the characteristic transient and frequency responses of time-average(continuous) power-stage models for use in designing and understanding the behavior of corresponding switched power stages. Novel conclusions include the dependence of

G. W. Wester; R. D. Middlebrook

1973-01-01

125

Bidirectional three phase power converter  

Microsoft Academic Search

This research aimed to design a three-phase ac-dc buck converter to achieve low-THO unity-power-fact or sinusoidal input current and regulated dc voltage via modified pulse-width-modu lation (PWM) technique. A 6-switch topology with bidirectional power flow capability is presented. The modified PWM switching strategy is discussed and verified via Matlab-Simulink and implemented in Digital Signal Processor (DSP) TMS320F28335. The topology and

Azrita Alias; Nasrudin Abd. Rahim; Mohd Azlan Hussain

2011-01-01

126

A review of three-phase improved power quality AC-DC converters  

Microsoft Academic Search

Three-phase AC-DC converters have been developed to a matured level with improved power quality in terms of power-factor correction, reduced total harmonic distortion at input AC mains, and regulated DC output in buck, boost, buck-boost, multilevel, and multipulse modes with unidirectional and bidirectional power flow. This paper presents an exhaustive review of three-phase improved power quality AC-DC converters (IPQCs) configurations,

Bhim Singh; Brij N. Singh; Ambrish Chandra; Kamal Al-Haddad; Ashish Pandey; Dwarka P. Kothari

2004-01-01

127

Mathematical models of dc\\/dc PWM converters applied to closed loop stability studies  

Microsoft Academic Search

The principles and results of a dynamic study of pulse-width modulator dc\\/dc converters are described. Three types of converters are considered: buck, boost, and buck-boost. The fundamental object is the establishing of equations of state describing the dynamic behavior of the power supply circuits. The non-unloading and unloading modes are considered. An analysis is carried out using the Laplace transform,

Y. Robin-Jouan

1975-01-01

128

Characteristics of the multiple-input DC-DC converter  

Microsoft Academic Search

A multiple-input DC-DC converter is proposed for realizing a clean electric power generation system. The two-input buck-boost type converter is analyzed, and the static and dynamic characteristics are clarified theoretically and are confirmed by experiment

H. Matsuo; T. Shigemizu; F. Kurokawa; N. Watanabe

1993-01-01

129

Development of custom radiation-tolerant DCDC converter ASICs  

NASA Astrophysics Data System (ADS)

Based on a detailed study of the radiation tolerance of high-voltage transistors, 2 commercial CMOS technologies have been selected for the design of synchronous buck DCDC converter ASICs. Three prototype converters have been produced, embedding increasingly sophisticated functions. The electrical and radiation performance of these prototypes is presented.

Faccio, F.; Michelis, S.; Orlandi, S.; Blanchot, G.; Fuentes, C.; Saggini, S.; Ongaro, F.

2010-11-01

130

New PWM switched-mode converter topologies  

NASA Astrophysics Data System (ADS)

Two augmented switching cells are proposed from which four novel topologies can be derived: an augmented buck converter, an augmented boost converter, a novel switching power amplifier, and a novel switching controlled rectifier. The augmented buck and the augmented boost converters realize higher step-down and step-up ratios, respectively, under a given switch duty ratio by proper design of the turn ratios of the transformer and coupled inductor. The switching power amplifier achieves four-quadrant output by the use of two bidirectional current switches and a single power supply, while the inverse converter can be used as a switching controlled rectifier. The experimental verification of the power amplifier is presented.

Hua, Gui-Chao; Huang, Shi-Peng

131

Closed-loop input and output impedances of DC-DC switching converters operating in voltage and current mode control  

Microsoft Academic Search

This work derives the closed-loop input and output impedances of three major types of DC-DC converters (Buck, Boost, and Buck-Boost) operating in voltage or current mode control. First, it introduces the small-signal converter model employed to derive the input and output impedances. Next, it reviews open-loop impedances for use in simplifying the expressions developed for closed-loop impedances. It then derives

Reza Ahmadi; Darren Paschedag; Mehdi Ferdowsi

2010-01-01

132

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

133

Improved power quality three phase AC-DC converter  

Microsoft Academic Search

Because of increasing applications of power electronic ac-dc converters, it's necessary to implement the single stage converter that can reliably perform both buck and boost operations. Traditionally, this can be achieved by double stage conversion (ac\\/dc-dc\\/dc) but ultimately leading to less efficiency and complex control. The novel ac-dc impedance-source converter, abbreviated as Z-source rectifier, has high power quality level and

Seyed Hossein Hosseini; F. Sedaghati; M. Sarhangzadeh

2010-01-01

134

Small-signal analysis of open-loop PWM flyback dc-dc converter for CCM  

Microsoft Academic Search

A flyback dc-dc converter is obtained from the conventional buck-boost converter by replacing the inductor with an isolation transformer. A transformer in the flyback converter is used to achieve a dc isolation between the input and the output of the converter. This paper presents dc and small-signal circuit models for the flyback converter for continuous conduction mode (CCM). The parasitic

Marian K. Kazimierczuk; Sonny T. Nguyen

1995-01-01

135

Passivity-Based Controllers for the Stabilization of DC-to-DC Power Converters  

Microsoft Academic Search

Passivity--based feedback controllers are derived for the indirect stabilization of the averageoutput voltage in Pulse--Width--Modulation (PWM) controlled dc--to--dc power converters of the"boost", "buck--boost" and "buck" types. The controller design is carried out on the basis of wellknown average PWM models of such circuits. These models are shown to be Euler--Lagrange systemscorresponding to a suitable set of average Euler--Lagrange parameters. The

Hebertt Sira-ramírez; Romeo Ortega

1997-01-01

136

Piaget, Marx, and Buck-Morss on Cognitive Development  

Microsoft Academic Search

Piaget’s and Marx’s cognitive theories of development are briefly compared and contrasted. This provides the necessary background and context for a critical look at Buck-Morss’ Marxian interpretation of cross-cultural differences in performance on Piagetian abstract formal reasoning tests. It is concluded that Buck-Morss’ view does not have contemporary truth value in light of certain non-real contractions which are inherent in

Allan R. Buss

1977-01-01

137

Multiphase LLC Series Resonant Converter for Microprocessor Voltage Regulation  

Microsoft Academic Search

In order to further reduce the power loss, and increase the computation speed, future microprocessors desires lower voltage, higher current, tighter voltage regulation, and faster transient from their voltage regulators. In the last decade, interleaved buck converters have been studied and used extensively for powering microprocessors. Due to their inherent limitations in current sharing, capacitor size, step down ratio, and

Taotao Jin; Keyue Smedley

2006-01-01

138

Soft switching active snubbers for DC/DC converters  

SciTech Connect

A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber capacitor during turn-off. The generic snubber cell for the buck converter is generalized to support the common nonisolated dc/dc converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated dc/dc converters (forward, flyback, Cuk, and sepic).

Elasser, A.; Torrey, D.A. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electric Power Engineering

1996-09-01

139

Family of single-inductor multi-output DC-DC converters  

Microsoft Academic Search

This paper presents the family of the single-inductor multi-output DC-DC converters. Conventional transformer-based multi-output DC-DC converters are proposed to provide multiple output voltages, which, however, have the drawbacks of high cost and large volume. Therefore, the single-inductor multi-output three-terminal configuration is developed in order to reduce the component count and cost for multi-output DC-DC converters, including the boost, buck, buck-boost,

Ray-Lee Lin; Chi-Rung Pan; Kuang-Hua Liu

2009-01-01

140

Harmonic analysis of nondeterministic switching methods for DC-DC power converters  

Microsoft Academic Search

The authors present a rigorous theoretical harmonic analysis of random pulse width modulation (RPWM) method and random pulse position modulation (RPPM) method for dc-dc converters. The theoretical relationships of discrete harmonics, continuous noise and output voltage ripple of the RPWM and RPPM schemes are established and compared with those of a standard deterministic PWM scheme in a buck converter. Limitations

Yash Shrivastava; S. Y. Hui; S. Sathiakumar; H. Shu-Hung Chung; K. K. Tse

2000-01-01

141

Modeling of chaotic DC-DC converters by iterated nonlinear mappings  

Microsoft Academic Search

In parameter ranges where conventional methods break down, DC-DC converters may be described by iterated mappings, a nonlinear discrete modeling technique. The underlying principles are explained and are applied to the example of a PWM-controlled buck converter. Stable behavior and bifurcations to chaos are predicted by numerical evaluation of the governing mapping and are confirmed by experiment

David C. Hamill; Jonathan H. B. Deane; David J. Jefferies

1992-01-01

142

Performance evaluation of silicon and gallium nitride power FETs for DC\\/DC power converter applications  

Microsoft Academic Search

Detailed performance evaluation of silicon and GaN power FETs is presented for chip-scale DC\\/DC converter applications. It is shown that improved GaN power FETs and silicon MOS power diodes can potentially lead to nearly 90% power conversion efficiency when switched at 5 MHz in a synchronous buck converter topology.

Krishna Shenai; Krushal Shah; Huili Xing

2010-01-01

143

Analysis of Inductor Current Sharing in Nonisolated and Isolated Multiphase dc–dc Converters  

Microsoft Academic Search

Current sharing among inductors is an important issue in both isolated and nonisolated dc-dc converters. In this paper, average current sharing is in-depth modeled and analyzed for both interleaved multiphase buck converters and isolated current-doubler dc-dc converters. The features and comparison of various current-sharing techniques used in isolated and nonisolated dc-dc converters are presented, and the corresponding design guidelines are

Hong Mao; Liangbin Yao; Caisheng Wang; Issa Batarseh

2007-01-01

144

Current ripple bounds in interleaved DC-DC power converters  

Microsoft Academic Search

In distributed power supply systems, the parallelism of DC-DC power converters is a basic architecture. In this paper, the authors use the time domain method to show that the amplitude of the input\\/output current ripple of N(⩾1) parallelly interleaved modules is always upper bounded by that of the individual modules for buck, boost, flyback, Cuk, and SEPIC power converters if

Chin Chang

1995-01-01

145

19. Photocopy of photograph (source uncertain; probably Bucks County Historical ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Photocopy of photograph (source uncertain; probably Bucks County Historical Society) ca. 1916, photographer unknown SHOWING CONSTRUCTION ESSENTIALLY COMPLETED. MERCER'S CAPTION READS: 'ON SATURDAY EVENING, NOVEMBER 13th AT 5: 15 P.M. THE WORKMEN HAVING AT FIVE O'CLOCK FINISHED THE CONSTRUCTION OF THE NEW BUILDING OF THE MUSEUM OF THE BUCKS COUNTY HISTORICAL SOCIETY AT DOYLESTOWN, A BAND OF TRAVELLING MUSICIANS STOPPED UNASKED AT NO. 196 GREEN STREET OPPOSITE THE SOUTHEAST GABLE OF THE BUILDING AND I HEARD THEM PLAY THE GERMAN SONG SHOWN BELOW, TRANSLATED 'WE HAD BUILT A STATELY HOUSE, AND DEDICATED IT TO GOD, AGAINST RAIN, STORM AND DISASTER' I CALLED THEM BACK TO PLAY IT AGAIN, BUT THEY MISUNDERSTOOD ME AND WENT AWAY. HENRY C. MERCER' - Mercer Museum, Pine & Ashland Streets, Doylestown, Bucks County, PA

146

The Two-User Seating Buck: Enabling Face-to-Face Discussions of Novel Car Interface Concepts  

Microsoft Academic Search

The automotive industry uses physical seating bucks, which are minimal mockups of a car interior, to assess various aspects of the planned interior early in the development process. In a virtual seating buck, users wear a head-mounted display (HMD) which overlays a virtual car interior on a physical seating buck. We have developed a two-user virtual seating buck system, which

Holger Salzmann; Bernd Froehlich

2008-01-01

147

Variable Step-Size AutoTuning Algorithm for Digital Power Converter with VariableSwitching-Frequency  

Microsoft Academic Search

This paper presents the analysis and implementation of a digital controller with adaptive auto- tuning algorithm that has a variable step size to track and detect the optimum switching frequency for a DC-DC converter. The algorithm is theoretically analyzed and developed based on buck DC-DC converter loss model and behavior and directed towered improving the convergence speed and accuracy of

Jaber A. Abu-Qahouq; Wisam Al-Hoor; Wasfy B. Mikhael; Lilly Huang; Issa Batarseh

2007-01-01

148

Minimizing the Output Voltage Ripple of a DC\\/DC Power Converter by Phase Locking  

Microsoft Academic Search

Reduced passives size and improved quality factor (Q) for an on-chip inductor can be achieved in a fully integrated DC\\/DC power converter by high frequency switching. This paper presents a high speed closed-loop buck converter that uses phase locking control system to reduce output voltage ripple. A closed-loop DC\\/DC power converter has been designed in a TSMC-0.25¿m technology. The power

Prabal Upadhyaya; Herbert L. Hess

2007-01-01

149

Buck v. Bell: A Constitutional Tragedy from a Lost World  

Microsoft Academic Search

Some constitutional tragedies are well known: Plessy v. Ferguson and Korematsu v. United States are taught to every first-year law student. Buck v. Bell is not. Decided in 1927 by the Taft Court, the case is known for its shocking remedy--sterilization--and Justice Holmes's dramatic rhetoric: \\

Victoria Nourse

2011-01-01

150

"The Bell Curve" and Carrie Buck: Eugenics Revisited.  

ERIC Educational Resources Information Center

The 1994 publication of "The Bell Curve" by R. Herrnstein and C. Murray is compared to other examples of eugenic principles, including the sterilization of "feebleminded" Carrie Buck, family degeneracy studies focusing on lower class Caucasian families, and other works that view the poorest and least educated members of society as problems for…

Smith, J. David

1995-01-01

151

BUCKS LAKE AND CHIPS CREEK ROADLESS AREAS, CALIFORNIA.  

USGS Publications Warehouse

The results of a mineral-resource assessment of the Bucks Lake and Chips Creek Roadless Areas, California indicate several areas with mineral-resource potential. The presence or absence of these potentially auriferous deposits can best be determined by drilling through the relatively thin cover of volcanic rocks.

Sorensen, Martin, L.; Linne, J. Mitchell

1984-01-01

152

Recognition of dynamic patterns in dc-dc switching converters  

NASA Astrophysics Data System (ADS)

Techniques are presented for analyzing the dynamic patterns of power flow in high-frequency dc-dc switching converters. Emphasis is placed on exploring methods for developing reduced-order models of power electronic circuits for simulation and state-space averaging. Tools from selective modal analysis are used to develop the dynamic pattern recognition algorithm that facilitates the classification of circuit modules. The algorithm is intended for the analysis of converters derived from the canonical switching call, i.e., the buck, boost, and flyback converters.

Leeb, Steven B.; Kirtley, James L.; Verghese, George C.

153

Diodes as pseudo active elements in high frequency dc/dc converters  

NASA Astrophysics Data System (ADS)

An approach to realizing zero-voltage switching in the entire family of high-frequency dc-dc converters is proposed. Utilizing the parasitic associated with the diode stored charge, it is shown that the diode reverse current established for charge removal can be used advantageously to accomplish soft switching. The resulting converter topologies differ from their hard-switched counterparts only by the presence of a resonant capacitor. Device and component stresses are moderate compared to existing quasi-resonant and resonant techniques. Converter analysis is complex as a result of the dominant diode nonlinearities, and no closed-form expressions are possible. Converter transfer characteristics are obtained through simulation, and operating limits are analytically obtained. The concept is validated by experimental results on buck, buck-boost, and boost converters rated approximately 100 W and operating at frequencies around 1 MHz.

Divan, D. M.

154

Model-free adaptive control for model mismatch power converters  

Microsoft Academic Search

This article proposes a model-free adaptive contr- oller?ƒ MFAC?? for BUCK converter by date- driven. It uses the model-free adaptive control algorithm based on the tight for- mat linear method; this method has achieved an intelligent rea- soning of the algorithm, and has rapid convergence for nonlin- ear controlled objects, so it restrains the time-varying parame- ters, the model mismatch

First A. Wu Jianhua; Second B. Yang Haitao; Third C. Zhang Haixin; Forth D. Zhu Mingguang

2011-01-01

155

Soft switching active snubbers for DC\\/DC converters  

Microsoft Academic Search

A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck power converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates

A. Elasser; D. A. Torrey

1996-01-01

156

Analysis and evaluation of overcurrent protection for DC to DC PWM converters  

Microsoft Academic Search

Overcurrent protection by sensing the top switch current with the peak current limiting or the bottom switch current with the valley current limiting in a buck converter is analyzed and the analysis is extended to other topologies. It is investigated that the auto soft restart \\

Jian Yang

2004-01-01

157

QFT based robust controller design for a DC-DC switching power converter  

Microsoft Academic Search

In this paper, a quantitative feedback theory (QFT) was applied successfully to design a robust controller for a DC-DC buck converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The controller is designed to provide optimum attenuation of the load disturbances in spite of practical limitations on the achievable closed-loop performance and in the presence of other

Ali Altowati; Kai Zenger; Teuvo Suntio

2007-01-01

158

H? control with pole location for a DC-DC converter with a switched load  

Microsoft Academic Search

This paper addresses the problem of control design for a DC-DC Buck converter with a switched load by means of state feedback. Sufficient conditions for the existence of a stabilizing control law are given in terms of linear matrix inequalities, guaranteeing: i) a specific pole location to the closed-loop system, when the load switches slowly enough to permit the accommodation

Vinicius E MONTAGNER; L. D. Peres

2003-01-01

159

Compensated gain control circuit for buck regulator command charge circuit  

DOEpatents

A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit.

Barrett, David M. (Albuquerque, NM)

1996-01-01

160

A ripple control buck regulator with fixed output frequency  

Microsoft Academic Search

This paper presents a ripple control buck regulator for stepping down high-voltage adaptor or battery supplies to low-voltage CPU core supply in notebook computers. Methods and circuits are proposed to achieve fixed switching frequency operation. The control loop adjusts delay of the controller and thus controls the output frequency. This is done by using a phase-frequency detector (PFD) to lock

Chung-Hsien Tso; Jiin-Chuan Wu

2003-01-01

161

Compensated gain control circuit for buck regulator command charge circuit  

DOEpatents

A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit. 5 figs.

Barrett, D.M.

1996-11-05

162

Modeling current-programmed buck and boost regulators  

Microsoft Academic Search

A general small-signal model for current-programmed switching power stages is used for design-oriented analysis of a 150 W buck regulator and a 280 W boost regulator. The model, into which the current-programming minor feedback loop is absorbed, exposes the desired tendency towards 'constant' output current. The regulator voltage loop remains the only explicit feedback loop, allowing the regulator closed-loop properties

R. D. Middlebrook

1989-01-01

163

Ferromagnetic resonance and magnetic carriers in Archean Buck Reef Chert from the Barberton Greenstone Belt, South Africa  

NASA Astrophysics Data System (ADS)

The nature of the magnetic carriers in the ˜3.4 billion year old Buck Reef Chert of the Barberton Greenstone Belt, South Africa, has been studied as it has been suggested that the chert may contain potential biogenic microstructures. Depositional environments of the Buck Reef Chert may have included shallow water environments and, as such, biogenic magnetite might be associated with them. Scanning Electron Microscope observations of magnetic separates and thin sections show cubo-octahedral to quasi-rectangular and hexagonally shaped grains that fall within a stable single domain range typical of biogenic magnetite. Preliminary transmission electron microscope and Energy Dispersive Spectrometer data have also been collected. Magnetic hysteresis properties of bulk samples show a variety of hysteresis behaviors (including multi-domain, pseudo-single domain and wasp-waisted curves). Analyses of bulk magnetic susceptibility versus temperature suggest alteration on heating (100-400 degrees C). Ferromagnetic resonance (FMR) has been used to investigate the possibility of magnetite produced by magnetotactic bacteria. Preliminary FMR spectra of some bulk Buck Reef Chert samples appear asymmetrical and skew towards low fields, suggesting a magnetic anisotropy that is similar to the spectra seen with some strains of magnetotactic bacteria. However, results to date should be interpreted in terms of the original depositional environment, and the subsequent geologic history. While some of the magnetic minerals within the separates observed in SEM may be primary, it is important to recognize low grade metamorphism has occurred to peak temperatures of 250 to 320 degrees C in the region. Depositional sulfides (e.g. greigite) in the originally sulfur rich environment may have been converted to other iron oxides during subsequent metamorphic events. We will discuss attempts to better distinguish primary from secondary magnetic minerals in the Barberton rocks.

Voronov, J.; Tarduno, J. A.; Cottrell, R. D.; Watkeys, M. K.; Hofmann, A.

2009-05-01

164

Three-Phase Z-Source AC-AC Converter for Motor Drives  

Microsoft Academic Search

This paper presents a Z-source ac-ac converter system and control for general-purpose motor drives. The Z-source ac-ac converter system employs a unique LC network to suppress the over-current and surge voltage due to the shoot-through or the open-circuit of the two switches. By controlling the duty cycle, the Z-source can provide buck-boost function, produce greater or less voltage than the

Xu-Peng Fang

2006-01-01

165

Performance characterization of a high-power dual active bridge DC-to-DC converter  

Microsoft Academic Search

The performance of a high-power, high-power-density DC-to-DC converter based on the single-phase dual active bridge (DAB) topology is described. The dual active bridge converter has been shown to have very attractive features in terms of low device and component stresses, small filter components, low switching losses, high power density and high efficiency, bidirectional power flow, buck-boost operation, and low sensitivity

Mustansir H. Kheraluwala; Randal W. Gascoigne; Deepakraj M. Divan; Eric D. Baumann

1992-01-01

166

A hybrid converter system for high performance large induction motor drives  

Microsoft Academic Search

A novel, hybrid converter system employing combination of a load-commutated inverter (LCI), a DC-DC buck converter, and a voltage-source inverter is proposed for the large induction motor drives. By avoiding the use of output capacitors and a forced decommutation circuit, this system can eliminate all disadvantages related to these circuits in the conventional LCI based induction motor drives. Improved quality

Sangshin Kwak; Hamid A. Toliyat

2004-01-01

167

A three-port half-bridge converter with synchronous rectification for renewable energy application  

Microsoft Academic Search

A three-port half-bridge converter for stand-alone renewable power system is proposed. The converter, featuring one input port, one bidirectional port and one isolated output port, is derived by integrating half-bridge, forward-flyback and Buck topologies. The magnetizing inductor of the transformer functions as an inductor, by which a power flow path can be configured between the renewable source and the battery,

Hongfei Wu; Yan Xing; Runruo Chen; Junjun Zhang; Kai Sun; Hongjuan Ge

2011-01-01

168

Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count  

Microsoft Academic Search

This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a

Poh Chiang Loh; Feng Gao; Pee-Chin Tan; Frede Blaabjerg

2007-01-01

169

Biological Determinism and the Concept of Mental Retardation: The Lesson of Carrie Buck.  

ERIC Educational Resources Information Center

|This paper reviews the case of Carrie Buck, who was the first person sterilized (in 1927) under a Virginia law allowing sterilization of persons identified as incompetent and likely to genetically transmit physical, psychological, or social deficiencies to their offspring. This law was later upheld by the Supreme Court in Buck v. Bell, which…

Smith, J. David

170

Power flow of photovoltaic system using buck-boost PWM power inverter  

Microsoft Academic Search

This paper presents a buck-boost PWM power inverter and its application for residential photovoltaic power systems. The PWM power inverter is realized by combining two sets of high frequency buck-boost choppers and by making them operate in the discontinuous conduction mode. A PV power system with the power inverter has the following advantages: (1) the power generated by the photovoltaic

Michihiko Nagao; Koosuke Harada

1997-01-01

171

Does a prosocial-selfish distinction help explain the biological affects? Comment on Buck (1999)  

Microsoft Academic Search

R. Buck (1999) argued that a conceptual distinction between prosocial and selfish motivation is necessary to understand the biological affects (consciously experienced feelings and desires having an innate neurochemical basis). However, at a biological level of analysis, a prosocial-selfish distinction is doubtful empirically and conceptually. For this reason, Buck's proposed typology of biological affects is unclear. Moreover, a prosocial-selfish distinction

Jeremy R. Gray

2002-01-01

172

The day before Buck vs. Bell, Paul LombardoSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Paul Lombardo DNAi Location:Chronicle>Trial of Carrie Buck>players>Carrie Buck>A cold day in November The day before the Virginia case, Arthur Estabrook photographed Carrie and Emma on a bench located at this spot in the Virginia Colony.

2008-10-06

173

Symmetrical dynamics of peak current-mode and valley current-mode controlled switching dc-dc converters with ramp compensation  

NASA Astrophysics Data System (ADS)

The discrete iterative map models of peak current-mode (PCM) and valley current-mode (VCM) controlled buck converters, boost converters, and buck-boost converters with ramp compensation are established and their dynamical behaviours are investigated by using the operation region, parameter space map, bifurcation diagram, and Lyapunov exponent spectrum. The research results indicate that ramp compensation extends the stable operation range of the PCM controlled switching dc-dc converter to D > 0.5 and that of the VCM controlled switching dc-dc converter to D < 0.5. Compared with PCM controlled switching dc-dc converters with ramp compensation, VCM controlled switching dc-dc converters with ramp compensation exhibit interesting symmetrical dynamics. Experimental results are given to verify the analysis results in this paper.

Zhou, Guo-Hua; Xu, Jian-Ping; Bao, Bo-Cheng; Jin, Yan-Yan

2010-06-01

174

Bookmark Converter  

NSDL National Science Digital Library

This windows utility enables user to convert their bookmarks from Netscape Navigator to Internet explorer and vice versa. It is small, fast, and simple to use. The latest version has been tested up to Netscape 4.6 and IE 5.0. Bookmark Converter is shareware and can be registered for $8.

Broding, Magnus.

175

Catalytic converter  

Microsoft Academic Search

A catalytic converter for oxidation of internal combustion engine exhausts is described which overcomes problems resulting from thermal expansion of core members and casings at a relatively low cost as compared to prior art solutions. The converter consists of pairs of circular and generally frusto-conical or funnel-shaped and concentric metal housings or casings forming a container surrounding a circularly cylindrical

1974-01-01

176

High-frequency high-voltage high-power DC-to-DC converters  

NASA Astrophysics Data System (ADS)

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-09-01

177

Optimal Design of Resonant Gate Driver for Buck Converter Based on a New Analytical Loss Model  

Microsoft Academic Search

In this paper, the advantages of a new resonant driver are verified thoroughly by the analytical analysis, simulation and experimental results. A new accurate analytical loss model of the power metal oxide semiconductor field effect transistor driven by a current-source resonant gate driver is developed. Closed-formed analytical equations are derived to investigate the switching characteristics due to the parasitic inductance.

Zhiliang Zhang; Wilson Eberle; Zhihua Yang; Yan-Fei Liu; Paresh C. Sen

2008-01-01

178

DC bus control of variable speed wind turbine using a buck-boost converter  

Microsoft Academic Search

For most of the peak power extraction methods in wind turbine generation system described in the current literature, it is necessary to know the wind turbine's maximum power curve and the wind speed measurement. These methods used the maximum power curve obtained via simulations or tests for individual wind turbines. This makes these methods difficult and expensive to implement in

T. Tafticht; K. Agbossou; A. Cheriti

2006-01-01

179

Single inductor quad-input-dual-output buck converter for photovoltaic systems  

Microsoft Academic Search

Stand-alone photovoltaic (SAPV) system is more favourable than grid connected photovoltaic (PV) system in areas where extension of power grid is impracticable. However, the high set up cost of a SAPV system requires cost efficient solar energy harvesting methods. To improve the energy harvesting efficiency of a PV system, a large, centrally controlled PV array can be rearranged into smaller

K. W. R. Chew; L. Siek

2010-01-01

180

Steady-state and dynamic performance analysis of PV supplied DC motors fed from intermediate power converter  

Microsoft Academic Search

The steady-state and transient performance of PM and series motors coupled to centrifugal pump supplied from Photovoltaic source through intermediate buck-boost converter is analyzed. The effect of duty ratio selection based on maximum power operation of PV source and maximum daily gross mechanical power is investigated on the solar cell array operating point, motor armature voltage, armature current and motor

Veera Chary Mummadi

2000-01-01

181

Feeding and reproductive behaviour in fallow bucks (Dama dama)  

NASA Astrophysics Data System (ADS)

Observations on individually marked fallow deer (Dama dama) in central Italy were performed over 2 years in order to analyse time budgets of four age and sex classes. The aim was to test whether feeding activity was influenced by mating activity, forage quality or physiological constraints during the rut. Only adult males (bucks) completely ceased feeding during the rutting season, well before the actual start of mating behaviour and concurrently with the phenomenon of scent-urination, and spending most of their daily time completely inactive. All other age and sex classes were unaffected in their feeding behaviour by the rutting season. Indeed, females and young males showed a marked increase in grazing in response to an improvement in forage quality from summer to autumn. These results seem to confirm the hypothesis that hypophagia, displayed only by bucks, may be of no adaptive value in itself. On the other hand, it may be a by-product of other physiological processes occurring during the rut, inducing scent-urination, which plays an important role in intraspecific recognition and sexual attraction.

Apollonio, Marco; Vittorio, Irene

2004-12-01

182

Optimum efficiency-tracking gate driver using adaptive deadtime control for single chip DC-DC converter  

Microsoft Academic Search

An optimum efficiency-tracking gate driver for single-chip DC-DC converter is proposed. It prevents an anti-parallel diode turn-on by adaptive deadtime control in sub-ns order. So it minimizes voltage and current spikes during switching transient, which results in high efficiency and EMI performance. Proposed gate driver is applied to buck converter using 0.35 mum CMOS process

Young Uk Hong; Bae Kun Choi; Young Jin Woo; Min Chull Lee; Tae Woo Kwak; Han Phuc Le; Gyu Hyeong Cho

2006-01-01

183

Multiple-input dc-dc converters to enhance local availability in grids using distributed generation resources  

Microsoft Academic Search

This paper analyzes a multiple-input converter topology with boost and buck-boost input legs that serves to integrate several different distributed generation sources into a common system dc bus. The multiple-input converter is arranged in modules that hold the common parts and in sub-modules that contain each input leg component. The result is a flexible and easily scalable system suitable for

Alexis Kwasinski; Philip T. Krein

2007-01-01

184

Minimum PCB footprint point-of-load DC-DC converter realized with Switched-Capacitor architecture  

Microsoft Academic Search

This work reports on the design and test of a CMOS-based switched capacitor (SC) DC-DC conversion integrated circuit (IC) for the point-of-load (POL) application conventionally addressed with the buck converter. A 12V-to-1.5V converter is fabricated in a 0.18 mum technology, with an active die area of 3mm2. There is a significant reduction in printed circuit board (PCB) footprint, passive component

Vincent W Ng; Michael D Seeman; Seth R Sanders

2009-01-01

185

A novel closed loop operated soft switched DC to DC converter fed DC motor for electric vehicles  

Microsoft Academic Search

A new feedback control scheme of DC motors which can can be easily implemented using PWM DC-DC power converters is proposed. This control minimizes the switching losses, eliminates electromagnetic interference (EMI) and improves efficiency. The simulation of the open loop and closed loop operations of a buck-boost constant frequency (CF) zero voltage switching (ZVS) quasi-resonant power converter (QRC) feeding a

G. Ume; C. Chellamutha

2000-01-01

186

Photothermophotovoltaic converter  

SciTech Connect

A photothermophotovoltaic energy conversion system for converting solar energy to electrical energy is described comprising: a radiator; and photovoltaic cell means for receiving incoming electromagnetic radiant energy including the solar energy and converting a first portion of the incoming energy to electrical energy and having reflecting means for reflecting a second portion of the incoming energy to the radiation. The radiator is disposed to receive the second portion of the energy from at least one photovoltaic cell and be heated thereby for radiating energy back to the photovoltaic cell means for subsequent energy conversion therein.

Woolf, L.D.

1988-05-24

187

How Buck vs. Bell began, Paul LombardoSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Paul Lombardo DNAi Location:Chronicle>Trial of carrie buck>trial Amherst County Courthouse Amherst County Courthouse was the first step of a legal case that would lead all the way to the Supreme Court.

2008-10-06

188

Lossless Dynamic Models of the Quasi-Z-Source Converter Family  

NASA Astrophysics Data System (ADS)

This paper is devoted to the quasi-Z-source (qZS) converter family. Recently, the qZS-converters have attracted attention because of their specific properties of voltage boost and buck functions with a single switching stage, which could be especially beneficial in renewable energy applications. As main representatives of the qZS-converter family, the traditional quasi-Z-source inverter as well as two novel extended boost quasi-Z-source inverters are discussed. Lossless dynamic models of these topologies are presented and analyzed.

Vinnikov, Dmitri; Husev, Oleksandr; Roasto, Indrek

2011-01-01

189

Measurement Converter  

NSDL National Science Digital Library

Many online calculators require a Java-capable browser. Here's one that doesn't, and will perform over 500 different unit conversions for distance, area, volume, mass, speed, temperature, pressure, energy, power, force, etc. And when you convert, say, 5 kilometers to miles, you not only get the conversion result, but a wealth of related measurements and sample conversions.

2007-12-13

190

INSIGHTS FROM RARE EARTH ELEMENTS INTO THE GENESIS OF THE BUCK CREEK COMPLEX, CLAY COUNTY, NC  

Microsoft Academic Search

The Buck Creek complex is among the largest and most lithologically diverse of the mafic\\/ultramafic bodies found in the eastern Blue Ridge province of the southern Appala- chians. Rare-earth element (REE) analyses on a representative suite of Buck Creek am- phibolites and meta-troctolites supplements an ongoing undergraduate research pro- gram examining the origins and history of mafic\\/ultramafic units in southwestern

SUZETTE BERGER; DEBORAH COCHRANE; KYLA SIMONS; IVAN SAVOV; J. G. RYAN; V. L. P ETERSON

191

Topological Design and Modulation Strategy for Buck–Boost Three-Level Inverters  

Microsoft Academic Search

To date, designed topologies for DC-AC inversion with both voltage buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable buck-boost three-level inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed

Feng Gao; Poh Chiang Loh; Remus Teodorescu; Frede Blaabjerg; D. Mahinda Vilathgamuwa

2009-01-01

192

Bi-Frequency Modulated Quasi-Resonant Converters: Theory and Applications  

NASA Astrophysics Data System (ADS)

To avoid the variable frequency operation of quasi -resonant converters, many soft-switching PWM converters have been proposed, all of them require an auxiliary switch, which will increase the cost and complexity of the power supply system. In this thesis, a new kind of technique for quasi -resonant converters has been proposed, which is called the bi-frequency modulation technique. By operating the quasi-resonant converters at two switching frequencies, this technique enables quasi-resonant converters to achieve the soft-switching, at fixed switching frequencies, without an auxiliary switch. The steady-state analysis of four commonly used quasi-resonant converters, namely, ZVS buck, ZCS buck, ZVS boost, and ZCS boost converter has been presented. Using the concepts of equivalent sources, equivalent sinks, and resonant tank, the large signal models of these four quasi -resonant converters were developed. Based on these models, the steady-state control characteristics of BFM ZVS buck, BFM ZCS buck, BFM ZVS boost, and BFM ZCS boost converter have been derived. The functional block and design consideration of the bi-frequency controller were presented, and one of the implementations of the bi-frequency controller was given. A complete design example has been presented. Both computer simulations and experimental results have verified that the bi-frequency modulated quasi-resonant converters can achieve soft-switching, at fixed switching frequencies, without an auxiliary switch. One of the application of bi-frequency modulation technique is for EMI reduction. The basic principle of using BFM technique for EMI reduction was introduced. Based on the spectral analysis, the EMI performances of the PWM, variable-frequency, and bi-frequency modulated control signals was evaluated, and the BFM control signals show the lowest EMI emission. The bi-frequency modulated technique has also been applied to the power factor correction. A BFM zero -current switching boost converter has been designed for the power factor correction, and the simulation results show that the power factor has been improved.

Zhang, Yuefeng

1995-01-01

193

Steady-state analysis of the symmetrical push-pull power converter employing a matrix transformer  

Microsoft Academic Search

Data published for the symmetrical push-pull power converter (SPPPC) show that the matrix transformer and the cross-coupling capacitors in this buck-type topology introduce unusual waveforms and properties. Circuit operation is examined in order to seek a simplified explanation of the published observations. Steady-state performance is analyzed and design equations are developed using state-space averaging. It is found that the SPPPC

Ray-Shyang Lai; Khai D. T. Ngo; J. K. Watson

1992-01-01

194

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

195

A fuzzy-logic-controlled single-stage converter for PV-powered lighting system applications  

Microsoft Academic Search

This paper presents a fuzzy-logic-controlled single-stage power converter (SSC) for photovoltaic (PV)-powered lighting system applications. The SSC is the integration of a bidirectional buck-boost charger\\/discharger and a class-D series resonant parallel loaded inverter. The designed fuzzy logic controller (FLC) can control both the charging and discharging current, and can improve its dynamic and steady-state performance. Furthermore, a maximum power point

Tsai-Fu Wu; Chien-Hsuan Chang; Yu-Hai Chen

2000-01-01

196

Controlling chaos in DC\\/DC converters using optimal resonant parametric perturbation  

Microsoft Academic Search

The method of resonant parametric perturbation is a simple non-feedback chaos control method which is easy to implement in practice. In this paper, an optimal strategy is applied to stabilize an unstable orbit in a chaotically operating current-mode controlled buck-boost converter. Optimal values of initial phase angles are computed corresponding to mini- mum perturbation amplitudes. With this optimal perturbation, the

Yufei Zhou; Herbert H. C. Iu; Chi Kong Tse; Jun-ning Chen

2005-01-01

197

Robust pole location for a DC-DC converter through parameter dependent control  

Microsoft Academic Search

This paper addresses the problem of robust control design for a DC-DC buck converter by means of a parameter dependent state feedback gain. Sufficient conditions are given for the existence of a robust stabilizing control law which assures that, for the uncertain closed-loop system, a prespecified pole location exists inside a circle on the left-hand half of the complex plane.

Vinicius Foletto Montagner; Pedro Luis Dias Peres

2003-01-01

198

A new flyback-current-fed push-pull DC-DC converter  

Microsoft Academic Search

This paper introduces a new flyback-current-fed push-pull DC-DC power converter whose significant advantages in comparison with conventional designs are: reduction in the number of output diodes; and unified output characteristics to represent both the buck and the boost operation modes in the continuous conduction mode. Theoretical analysis, design methodology and experimental results taken from a 600 W, 25 kHz laboratory

D. A. Ruiz-Caballero; I. Barbi

1998-01-01

199

A new flyback-current-fed push-pull DC-DC converter  

Microsoft Academic Search

This paper introduces a new flyback-current-fed push-pull DC-DC converter whose significant advantages in comparison with the conventional one are a reduction in the number of output diodes and unified output characteristics to represent both the buck and the boost operation modes in the continuous conduction mode. Theoretical analysis, design methodology and experimental results taken from a 600 W 25 kHz

Domingo A. Ruiz-Caballero; Ivo Barbi

1999-01-01

200

Five-Level Diode-Clamped PWM Converters Connected Back-to-Back for Motor Drives  

Microsoft Academic Search

This paper addresses a transformerless medium-voltage adjustable-speed motor drive consisting of two five-level diode-clamped PWM converters connected back-to-back. It is followed by designing, constructing, and testing a 200-V downscaled model to verify the validity and effectiveness of the medium-voltage motor drive. This downscaled model has four split DC capacitors equipped with a voltage-balancing circuit using two bidirectional buck-boost choppers. The

Natchpong Hatti; Yosuke Kondo; Hirofumi Akagi

2008-01-01

201

Interpreted reflection seismic events near the North Central Oil Corporation Well, Newark Basin, Bucks County, Pennsylvania  

SciTech Connect

In 1985, North Central Oil Corporation drilled a 10,500-ft well in Bucks County, Pennsylvania, to test for oil and gas in Triassic-Jurassic strata of the Newark Group in the Newark basin. The hole was located about 5 mi southeast of the border fault on the crest of the Revere anticline, a transverse structure that plunges northwestward toward the border fault. This drill hole, No. 1 Cabot-KBI penetrated in descending order 2900 ft of lacustrine red and gray shale (Passaic Formation of Jurassic and Triassic age), 3600 ft of lacustrine gray and black shale (Lockagong Formation of Triassic age), and 4000 ft of fluvial sandstone and red shale (Stockton Formation of Triassic age). Although the drill hole abandoned, it revealed excellent gas shows throughout the Lockatong Formation and parts of the Stockton Formation. Acoustic and density logs from the well were converted to a synthetic seismogram that ties stratigraphic intervals in the borehole with seismic events on the nearby, 33-mi-long Seitel NB-1 seismic line. Formation contacts, probable intraformational unconformities, and lithologic units, such as 50-ft-thick fluvial sandstones in the Stockton Formation, are identified and traced for tens of miles away from the well. Moreover, beneath the drill site in the Stockton Formation, the 48-fold seismic line shows a large anticline that is subparallel to the border fault. This anticline has no surface expression, but, in combination with the intersecting Revere anticline, provides an obvious exploration target. Our interpretation suggests that the No. 1 Cabot-KBI drill hole ends about 1500 ft above the border fault and the underlying middle Proterozoic basement. High-amplitude seismic events from the Stockton Formation on the south-eastern flank of the large anticline may indicate undiscovered gas accumulations.

Ryder, R.T.; Miller, J.J.; Grow, J.A.; Ratcliffe, N.M. (Geological Survey, Reston, VA (United States))

1993-08-01

202

General-purpose fuzzy controller for dc-dc converters  

SciTech Connect

In this paper, a general-purpose fuzzy controller for dc-dc converters is investigated. Based on a qualitative description of the system to be controlled, fuzzy controllers are capable of good performances, even for those systems where linear control techniques fail, e.g., when a mathematical description is not available or is in the presence of wide parameter variations. The presented approach is general and can be applied to any dc-dc converter topologies. Controller implementation is relatively simple and can guarantee a small-signal response as fast and stable as other standard regulators and an improved large-signal response. Simulation results of Buck-Boost and Sepic converters show control potentialities.

Mattavelli, P.; Rossetto, L.; Spiazzi, G.; Tenti, P. [Univ. of Padova (Italy)

1997-01-01

203

Radiation effects in power converters: Design of a radiation hardened integrated switching DC/DC converter  

NASA Astrophysics Data System (ADS)

When electronic devices are used in space and military systems, they may be exposed to various types of radiation, including photons, electrons, protons, neutrons, and heavy ions. The effects of radiation on the semiconductor devices within the systems range from gradual degradation to catastrophic failure. In order to design and produce reliable systems for space or military applications, it is necessary to understand the device-level effects of radiation and develop appropriate strategies for reducing system susceptibility. This research focuses on understanding radiation effects in power converters for space and military applications. We show that power converters are very sensitive to radiation (total-dose, single event effects and displacement damage) and that their radiation response is dependent on input bias conditions and load conditions. We compared the radiation hardness of various power converter topologies using experiments and simulations. Evaluation of these designs under different modes of operation is demonstrated to be critical for determining radiation hardness. We emphasize the correlation between radiation effects and the role of the dynamic response of these topologies. For instance, total dose exposure has been found to degrade loop gain and affect regulation in some converters. We propose several radiation-hardening solutions to improve the radiation response of these designs. For instance, we demonstrate the design of a digitally controlled boost converter suitable for space applications based on an SRAM FPGA. A design hardening solution has been developed and successfully applied through VHDL simulations and experiments to assure the continuous operation of the converter in the presence of SEES (more precisely SEFIs). This research led to the design of a digitally controlled radiation hardened integrated switching buck converter. The proposed design is suitable for micro-satellite applications and is based on a high-voltage/CMOS process. This design is the first radiation-hardened DC/DC power converter in this power range that integrates the switch, controller, and rectifier. The design has been fabricated, simulated and tested.

Adell, Philippe

204

A novel PWM control for a bi-directional full-bridge DC–DC converter with smooth conversion mode transitions  

Microsoft Academic Search

A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC–DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC–DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of

V. R. H. Lorentz; H. Schwarzmann; M. März; A. J. Bauer; H. Ryssel; L. Frey; P. Poure; F. Braun

2011-01-01

205

A Novel Soft-Commutating Isolated Boost Full-Bridge ZVS-PWM DC–DC Converter for Bidirectional High Power Applications  

Microsoft Academic Search

A soft-commutating method and control scheme for an isolated boost full bridge converter is proposed in this paper to implement dual operation of the well-known soft-switching full bridge dc\\/dc buck converter for bidirectional high power applications. It provides a unique commutation logic to minimize a mismatch between current in the current-fed inductor and current in the leakage inductance of the

Lizhi Zhu

2006-01-01

206

A novel soft-commutating isolated boost full-bridge ZVS-PWM DC-DC converter for bidirectional high power applications  

Microsoft Academic Search

A soft-commutating method and control scheme for an isolated boost full bridge converter is proposed in this paper to implement dual operation of the well-known soft switching full bridge DC\\/DC (buck) converter for bi-directional high power applications. It provides a unique commutation logic to minimize a mismatch between current in the current-fed inductor and current in the leakage inductance of

Lizhi Zhu

2004-01-01

207

A high efficiency topology for 12 V VRM-push-pull buck and its integrated magnetics implementations  

Microsoft Academic Search

As computer processors move forward quickly, their power management becomes more and more challenging. Nowadays, for the desktop and workstation applications, voltage regulator module (VRM) input voltage has moved to the 12 V output of the silver box. The state of the art 12 V VRM topology is buck. Because of the extreme duty-cycle, buck has a lot of limitations

Jia Wei; Peng Xu; Fred C. Lee

2002-01-01

208

Public Health Assessment for Dublin Water Supply, Dublin, Bucks County, Pennsylvania, Region 3. CERCLIS No. PAD981740004.  

National Technical Information Service (NTIS)

The Dublin TCE Site (formerly the Dublin Water Supply Site) is a National Priorities List Update 10 site located at 120 Mill Street in Dublin Borough, Bucks County, Pennsylvania. During a routine drinking water survey in 1986, the Bucks County Health Depa...

1994-01-01

209

Gertrude Buck's Approach to Argumentation: Preparing Women for a More Active and Vocal Role in a Democracy.  

ERIC Educational Resources Information Center

|Explores Gertrude Buck's approach to argumentation demonstrating the intellectual and social significance of her work and showing how she introduced a democratic ethics encouraging Vassar women to take a more active and public role in society. Focuses on one of Buck's instruments of teaching writing, "A Course in Argumentative Writing" (1899),…

Bordelon, Suzanne

1998-01-01

210

Three-Level AC–DC–AC Z-Source Converter Using Reduced Passive Component Count  

Microsoft Academic Search

This paper presents a three-level AC-DC-AC Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low-cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected

Poh Chiang Loh; Feng Gao; Pee-Chin Tan; Frede Blaabjerg

2009-01-01

211

Application of digital control techniques for satellite medium power DC-DC converters  

NASA Astrophysics Data System (ADS)

The objective of this paper is to present a work concerning a digital control loop system for satellite medium power DC-DC converters that is done in Space Research Centre. The whole control process of a described power converter bases on a high speed digital signal processing. The paper presents a development of a FPGA digital controller for voltage mode stabilization that was implemented using VHDL. The described controllers are a classical digital PID controller and a bang-bang controller. The used converter for testing is a simple model of 5-20 W, 200 kHz buck power converter. A high resolution digital PWM approach is presented. Additionally a simple and effective solution of filtering of an analog-to-digital converter output is presented.

Skup, Konrad R.; Grudzinski, Pawel; Nowosielski, Witold; Orleanski, Piotr; Wawrzaszek, Roman

2010-06-01

212

A continuous nonlinear model approach to study the behavior of large signal DC to DC converters  

NASA Astrophysics Data System (ADS)

The study of signal switching DC-DC converters behavior is addressed. Given the fact that the linear methods cannot be used in this case, a nonlinear model was developed. The power stage nonlinear continuous model, which can be applied in both conduction modes (continuous and discontinuous), is obtained from the partition of the characteristic state vector variables in two subsets. This method is applied to the elementary switching cells (buck, boost, and buck-boost) and Cuk converter. It is oriented to the fast numerical simulation by means of general purpose simulation programs. Different results from numerical simulations, confirming the accuracy of the method used, either in an open loop or in a closed loop, are obtained, provided the validity of its domain is respected. The nonlinear model linearization made it possible to obtain equivalent transmittances for the DC-DC converters. Its application to a boost converter operating in the discontinuous condition mode at variable frequency rate enables the comparison of the obtained results with other existing methods and equivalence between the two of them to be easily established. The revision of the initial hypothesis leads to the establishment of a small signal model valid in the high frequency domain and to the results obtained being derived in a more systematic way. A model for switching DC-DC converters is given. Its validity is established, whatever its order and conduction modes, either in an open loop or a closed loop.

Guinjoan, Francisco

213

Theoretical and experimental investigation of the fast- and slow-scale instabilities of a DC-DC converter  

Microsoft Academic Search

We use an exact formulation based on nonlinear maps to investigate both the fast-scale and slow-scale instabilities of a voltage-mode buck converter operating in the continuous conduction mode and its interaction with a filter. Comparing the results of the exact model with those of the averaged model shows the shortcomings of the latter in predicting fast-scale instabilities. We show the

Sudip K. Mazumder; Ali H. Nayfeh; Dushan Boroyevich

2001-01-01

214

Research on the Reconfigurable Implementation of Neural Network Controller Based on FPGA for DC-DC Converters  

Microsoft Academic Search

A neural network controller for DC\\/DC buck converters is proposed, and then the hardware implementation problem of the controller\\u000a based on FPGA is discussed in this paper. The neural network is trained using bp method. The reconfigurable feature is analyzed\\u000a and then three basic reconfigurable units are built based on SG \\/ Simulink. The simulation results show that the FPGA-based

Yanxia Shen; Tai Li; Zhicheng Ji

2009-01-01

215

Closed-loop sampled-data error model for PWM DC\\/DC converters with input variations  

Microsoft Academic Search

This paper proposes an extended sampled-data error (small-signal) model of closed-loop Switched Mode Power Supplies (SMPS) operated with Pulse-Width Modulated (PWM) signals. This model includes a formulation of the input-to-state sensitivity matrix as well as support for non-linear ramps in expression of the switching conditions. A practical implementation of this model is derived for a Buck DC\\/DC converter operating in

S. Cliquennois

2010-01-01

216

A transformer-less inverter using buck-boost type chopper circuit for photovoltaic power system  

Microsoft Academic Search

This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. The proposed system consists of two sets of PV array and buck-boost type chopper circuit. However, the system has lower “using rate” of PV energy than that of the ordinary PV system, as each PV array is only operated in the half duration of

Nobuyuki Kasa; Haruki Ogawa; Takahiko Iida; Hideo Iwamoto

1999-01-01

217

1927 Buck vs. Bell trial, Paul LombardoSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Paul Lombardo DNAi Location:Chronicle>Trial of Carrie Buck>outcome Carrie's sterilization in context. Carrie's one-hour sterilization took place in 1927, the same year that Babe Ruth hit 60 home runs and Charles Lindbergh flew solo across the Atlantic.

2008-10-06

218

Analysis and control of Buck-Boost Chopper type AC voltage regulator  

Microsoft Academic Search

Traditional AC voltage regulator used servo-motor position regulation or thyristor phased controlled method which had low dynamic response speed or large amount of harmonic components. However, these drawbacks can be overcome by using Pusle Width Modulation chopper techniques in AC voltage regulation. Buck-Boost Chopper type AC voltage regulator, derived from the DC chopper modulated method, is a kind of direct

Jin Nan; Tang Hou-jun; Liu Wei; Ye Peng-sheng

2009-01-01

219

A new current-source gate driver for a buck voltage regulator  

Microsoft Academic Search

A new current-source gate drive circuit is proposed for a synchronous buck voltage regulator (VR). The proposed driver can drive two MOSFETs independently with different drive currents for optimal design. Furthermore, the new drive circuit can achieve 1) significant switching loss reduction; 2) gate energy recovery; 3) reduced body diode losses and reverse recovery losses; 4) ZVS of all the

Zhiliang Zhang; Wilson Eberle; Yan-Fei Liu; P. C. Sen

2008-01-01

220

Dynamic characteristics analysis and instantaneous value control design for buck-type power electronic transformer (PET)  

Microsoft Academic Search

Detail dynamic characteristics analysis of buck-type PET under general load condition was accomplished and the study showed that: under general inductive load condition, the open-loop system is marginally stable and serious output voltage oscillation can be provoked by any random disturbance upon input voltage, control signal or output current. Therefore, in order to ensure the out power quality, we must

Ma Huasheng; Zhang Bo; Zheng Jianchao; Liu Xuechao

2005-01-01

221

Production and Costs of Manual Delimbing, Bucking, and Piling in Thinnings.  

National Technical Information Service (NTIS)

Studies were made of chainsaw delimbing and bucking with manual piling of bunched trees to determine productivity rates and costs for each function. Information was obtained from observations of six thinning operations in the South. Average d.b.h. and bol...

B. J. Stokes B. L. Lanford

1986-01-01

222

A simple switching loss model for buck voltage regulators with current source drive  

Microsoft Academic Search

A review of switching loss mechanisms for synchronous buck voltage regulators is presented. Following the review, a new simple analytical switching loss model is proposed for voltage regulators with current source drive. The model includes the impact of common source inductance and parasitic inductance on switching loss. It uses simple equations to calculate the rise and fall times and piecewise

Wilson Eberle; Zhiliang Zhang; Yan-Fei Liu; Paresh Sen

2008-01-01

223

Adaptive neuron PID control of Buck type AC chopper voltage regulator  

Microsoft Academic Search

The PID controller has been used as the effective control method. The proper adjustment of the gains is of great importance to obtain the desired performance of the controller. However, it is necessary to find suitable PID gains automatically. This paper presents the modeling and control of Buck chopper type AC voltage regulator while the system is operating under uncertainty

Jin Nanl; Tang Hou-jun; Cui Guang-zhao

2009-01-01

224

Chaos, bifurcation and intermittent phenomena in DC-DC converters under resonant parametric perturbation  

NASA Astrophysics Data System (ADS)

DC-DC converters act as a black box to study various bifurcations. In the present study, the influence of external periodic interference signal in the input of DC-DC voltage-mode controlled buck converter has been considered. It is found that the presence of sinusoidal or saw-tooth interference signal whose frequency is comparable with the switching frequency of the converter or its rational multiples manifests as remerging chaotic band attractors (or Feigenbaum trees) and intermittent chaos. However, the presence of sinusoidal interference signal having irrational frequency ratios with the switching frequency of the converter leads to quasi-periodic route to chaos. The study was carried out both theoretically and experimentally.

Deivasundari, P.; Geetha, R.; Uma, G.; Murali, K.

2013-07-01

225

Carrie Buck's wedding photograph, still image with audio by Paul LombardoSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

DNAi location: Chronicle>Trial of Carrie Buck>epilogue Carrie Buck sent this photo, taken on her wedding day in 1933, to Dr. Bell, still at the Virginia Colony for Epileptics and Feebleminded. She remained married to Mr. Eagle, shown here in the wedding picture, for 25 years. Though it was claimed that she was unstable, morally uninhibited, and feebleminded, this first marriage lasted a quarter of a century until the death of her spouse.

2008-10-06

226

A 5MHz 91% PeakPower-Efficiency Buck Regulator With Auto-Selectable Peak and Valley-Current Control  

Microsoft Academic Search

This paper presents a multi-MHz buck regulator for portable applications using an auto-selectable peak- and valley-current control (ASPVCC) scheme. The proposed AS- PVCC scheme can enable the current-mode buck regulator to reduce the settling-time requirement of the current sensing by two times. In addition, the dynamically biased shunt feedback technique is employed to improve the sensing speed and the sensing

Mengmeng Du; Hoi Lee; Jin Liu

2011-01-01

227

A Bidirectional High-Power-Quality Grid Interface With a Novel Bidirectional Noninverted Buck–Boost Converter for PHEVs  

Microsoft Academic Search

Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on

Omer C. Onar; Jonathan Kobayashi; Dylan C. Erb; Alireza Khaligh

2012-01-01

228

A new synchronous reluctance generator AC\\/DC buck rectifier as a controllable power supply  

Microsoft Academic Search

This paper sets forth the use of a three-phase synchronous reluctance generator feeding a pulse-width modulation (PWM) based AC\\/DC buck rectifier to produce controllable AC and\\/or DC power. This is made possible by controlling both the modulation magnitude and phase angle of the rectifier. This generating scheme is targeted for application requirements for equipment on airplanes, ships or ground vehicles

Olorunfemi Ojo; Ishwar Bhat

1994-01-01

229

Interpreted reflection seismic events near the North Central Oil Corporation Well, Newark Basin, Bucks County, Pennsylvania  

Microsoft Academic Search

In 1985, North Central Oil Corporation drilled a 10,500-ft well in Bucks County, Pennsylvania, to test for oil and gas in Triassic-Jurassic strata of the Newark Group in the Newark basin. The hole was located about 5 mi southeast of the border fault on the crest of the Revere anticline, a transverse structure that plunges northwestward toward the border fault.

R. T. Ryder; J. J. Miller; J. A. Grow; N. M. Ratcliffe

1993-01-01

230

A High Efficiency Synchronous Buck VRM with Current Source Gate Driver  

Microsoft Academic Search

In this paper, a new current source gate drive circuit is proposed for high efficiency synchronous buck VRMs. The proposed circuit achieves quick turn-on and turn-off transition times to reduce switching loss and conduction loss in power MOSFETS. The driver circuit consists of two sets of four control switches and two very small inductors (typically 50 nH-300 nH each at

Wilson Eberle; Zhiliang Zhang; Yan-Fei Liu; P. C. Sen

2007-01-01

231

Application of sliding-mode control to the design of a buck-based sinusoidal generator  

Microsoft Academic Search

This paper is devoted to the design of a sliding-mode control scheme for a buck-based inverter, with programmable amplitude, frequency, and DC offset, with no external sinusoidal reference required. A general procedure for obtaining an autonomous (time independent) switching surface from a time-dependent one is presented. For this surface, the system exhibits a zeroth-order dynamics in sliding motion. On the

Domingo Biel; Enric Fossas; Francisco Guinjoan; Eduard Alarcón; Alberto Poveda

2001-01-01

232

Tolazoline antagonises ketamine–xylazine anaesthesia in an endangered Black buck ( Antilope cervicapra )  

Microsoft Academic Search

Seventy-seven anaesthetic events were carried out in 22 captive adult Black bucks (Antilope cervicapra) of either sex with a combination of 2 mg kg?1 ketamine hydrochloride with 0.25 mg kg?1 xylazine hydrochloride using a dart delivered from a blowpipe. Randomised anaesthetised animals received an intravenous injection\\u000a of either yohimbine hydrochloride (0.125 or 0.25 mg kg?1) or tolazoline hydrochloride (1 or 2 mg kg?1) after

Sadanand D. Sontakke; Govindaswamy Umapathy; Manoj S. Patil; Sisinthy Shivaji

2009-01-01

233

Double-loop control and stability analysis based on three-phase Buck-Boost inverter  

Microsoft Academic Search

To develop and apply renewable energy, one of the key technologies is that a kind of inverter outputting high quality sinusoid signals to power network is required. This paper proposed a three-phase buck-boost inverter, which can generate a three-phase ac output voltage larger than the dc input one. Its basic configuration is introduced, and the system stability of open-loop is

Zhu Jianlin; Xiang Lidan; Liu Shasha

2008-01-01

234

A new control algorithm for three-phase PWM buck rectifier with input displacement factor compensation  

Microsoft Academic Search

A new control algorithm for the three-phase buck rectifier with an input filter is developed. The algorithm employs a separate control loop for compensation of the input current displacement factor in steady-state, in addition to the standard output voltage regulation loop. The algorithm allows separate design of the input filter and of closed-loop output voltage control. The design procedure is

S. Hiti; V. Vlatkovic; D. Borojevic; F. C. Y. Lee

1994-01-01

235

Experimental analysis of a DC bucking motor blocking geomagnetically induced currents  

Microsoft Academic Search

An experimental study investigates the performance of a dc bucking motor for the blocking of geomagnetically induced currents (GICs) within a 3 kVA\\/416 V three-phase distribution feeder. This blocking method consists of connecting a separately excited dc motor between neutral and ground of a Y-grounded transformer consisting of a bank of three single-phase transformers. Losses and currents of the transformer

A. A. Fardoun; E. F. Fuchs; M. A. S. Masoum

1994-01-01

236

Effect of nutrition on lipid production and composition of Cashmere buck fleece  

Microsoft Academic Search

This study examined the lipid content and fatty acid composition of fleece samples collected in April, which is during the breeding period, from different body regions of Cashmere bucks fed ad libitum diets of high (pelleted lucerne, Medicago sativa, 8.3 mJ kg?1 ME, 17.6% CP) and low (coarsely hammermilled pangola grass, Digitaria decumbens, 6.6 mJ kg?1 ME, 6.9% CP) quality.

G. C. Hillbrick; D. J. Tucker

1996-01-01

237

Operation principles of bi-directional full-bridge DC\\/DC converter with unified soft-switching scheme and soft-starting capability  

Microsoft Academic Search

A new bi-directional dual full-bridge DC\\/DC converter with a unified soft-switching scheme and soft-start capability is proposed in this paper. A simple voltage clamp branch is used to limit transient voltage across the current-fed bridge and realize zero-voltage-switching (ZVS) in boost mode operation, while achieving hybrid zero-voltage\\/zero-current switching (ZVZCS) for the voltage-fed bridge in buck mode operation. The theory of

Kunrong Wang; Fred C. Lee; Jason Lai

2000-01-01

238

Comparison of control structures for a bidirectional high-frequency dc-dc converter  

NASA Astrophysics Data System (ADS)

A system for dc-dc power conversion based on a buck-boost converter topology is presented. It makes power flow in both directions possible. The possibility of bidirectional power flow is useful for certain applications, such as uninterruptable power supplies. Starting from a structural diagram the transfer function of the system is derived. The controller for the converter is then designed. It is made up of a simple voltage controller, a voltage controller with an inner loop current controller (cascade control) and with two kinds of state space control. The transfer functions of the different system parts are derived and dimensioning guidelines for the controller sections are presented. The closed loop behavior of the bidirectional converter for the different control structures is analyzed based on simulation using duty cycle averaging. Bodediagrams and step responses are shown.

Himmelstoss, Felix A.; Kolar, Johann W.; Zach, Franz C.

1989-08-01

239

PWM Converter Topologies.  

National Technical Information Service (NTIS)

Dc to dc converters using an electrical switch to control power flow between a dc source and a dc load are discussed. Only Pulse Width Modulation (PWM) type converter topologies are considered. A basic three element, three terminal converter topology is d...

E. R. W. Meerman H. J. N. Spruyt

1989-01-01

240

Study of nonlinear phenomena in switching DC/DC converters  

NASA Astrophysics Data System (ADS)

This thesis studies some nonlinear phenomena such as bifurcation and chaos in DC/DC switching converters. Five phases of investigations are described. The first phase reviews the existing tools for analyzing nonlinear systems that are helpful to the investigation of nonlinear phenomena in power electronic circuits. Some of these existing tools are employed to study the nonlinear behaviour of power electronic circuits in the subsequent phases. The second phase focuses on the analysis of bifurcation behaviour of parallel-connected DC/DC converters under a master-slave current sharing scheme. An iterative discrete-time map and its Jacobian are established to predict the onset of period-doubling or Neimark-Sacker bifurcation. Both parallel-connected buck converters and boost converters are studied. The third phase studies an autonomous free-running Cuk converter under a hysteretic current-mode control. Hopf bifurcation is observed, for the first time, in this kind of autonomous power electronic circuits. The method of state-space averaging is employed to predict the occurrence of such bifurcation. Extensive simulations and experiments confirm the predicted results. A typical bifurcation sequence from stable fixed points to chaos, via limit cycles and quasiperiodic orbits, is demonstrated. The fourth phase investigates the possibility of synchronization of two chaotic autonomous free-running Cuk converters. With a particular capacitor voltage as driving signal, synchronization is found possible. Averaged state equations and conditional Lyapunov exponents are used to predict the possibility of synchronization while computer simulations and PSPICE simulations provide the verification. The last phase gives suggestions for future research.

Iu, Herbert Ho-Ching

241

Analysis of transistor and snubber turn-off dynamics in high-frequency high-voltage high-power converters  

NASA Astrophysics Data System (ADS)

Dc to dc converters which operate reliably and efficiently at switching frequencies high enough to effect substantial reductions in the size and weight of converter energy storage elements are studied. A two winding current or voltage stepup (buck boost) dc-to-dc converter power stage submodule designed to operate in the 2.5-kW range, with an input voltage range of 110 to 180 V dc, and an output voltage of 250 V dc is emphasized. In order to assess the limitations of present day component and circuit technologies, a design goal switching frequency of 10 kHz was maintained. The converter design requirements represent a unique combination of high frequency, high voltage, and high power operation. The turn off dynamics of the primary circuit power switching transistor and its associated turn off snubber circuitry are investigated.

Wilson, P. M.; Wilson, T. G.; Owen, H. A., Jr.

242

Predicted sex ratio of juvenile Hawksbill Seaturtles inhabiting Buck Island Reef national monument, U.S. Virgin Islands  

USGS Publications Warehouse

Hawksbill Seaturtles have temperature-dependent sex determination. As such, the resulting sex ratios are of conservational and ecological significance. Buck Island Reef is an interesting location for sex ratio studies since it represents a natural and unexploited foraging ground for hawksbills in the Caribbean. To examine sex ratios, blood samples were obtained from juvenile Hawksbill Seaturtles captured on Buck Island Reef over a four-year period. We used a radioimmunoassay to determine testosterone levels in those samples and compared those values to testosterone levels of juvenile hawksbills from the Caribbean whose sex has been verified by laparoscopy. The results of this study reveal a significantly female-biased sex ratio (approximately 80% female) occurs in this juvenile aggregation inhabiting Buck Island Reef.

Geis, A.; Wibbels, T.; Phillips, B.; Hillis-Starr, Z.; Meylan, A.; Meylan, P.; Diez, C.; Van Dam, R.

2003-01-01

243

Period-doubling bifurcation in two-stage power factor correction converters using the method of incremental harmonic balance and Floquet theory  

NASA Astrophysics Data System (ADS)

In this paper, period-doubling bifurcation in a two-stage power factor correction converter is analyzed by using the method of incremental harmonic balance (IHB) and Floquet theory. A two-stage power factor correction converter typically employs a cascade configuration of a pre-regulator boost power factor correction converter with average current mode control to achieve a near unity power factor and a tightly regulated post-regulator DC—DC Buck converter with voltage feedback control to regulate the output voltage. Based on the assumption that the tightly regulated post-regulator DC—DC Buck converter is represented as a constant power sink and some other assumptions, the simplified model of the two-stage power factor correction converter is derived and its approximate periodic solution is calculated by the method of IHB. And then, the stability of the system is investigated by using Floquet theory and the stable boundaries are presented on the selected parameter spaces. Finally, some experimental results are given to confirm the effectiveness of the theoretical analysis.

Wang, Fa-Qiang; Zhang, Hao; Ma, Xi-Kui

2012-02-01

244

Bucking coil implementation on PMT for active canceling of magnetic field  

NASA Astrophysics Data System (ADS)

Aerogel and water ?herenkov detectors were employed to tag kaons for a ? hypernuclear spectroscopic experiment which used the (e,e?K+) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 gauss at the photomultiplier tubes for these detectors. These fields, which could not be easily passively shielded, would result in a lowered kaon detection efficiency if not mitigated. A bucking coil was placed on each photomultiplier tube to actively cancel this magnetic field, thus recovering kaon detection efficiency.

Gogami, T.; Asaturyan, A.; Bono, J.; Baturin, P.; Chen, C.; Chiba, A.; Chiga, N.; Fujii, Y.; Hashimoto, O.; Kawama, D.; Maruta, T.; Maxwell, V.; Mkrtchyan, A.; Nagao, S.; Nakamura, S. N.; Reinhold, J.; Shichijo, A.; Tang, L.; Taniya, N.; Wood, S. A.; Ye, Z.

2013-11-01

245

GraphicConverter  

NSDL National Science Digital Library

GraphicConverter goes beyond the ability to convert a large number of graphic file formats. It provides tools for the creation and/or editing of graphics, animations, movies, and slide presentations; it also supports Adobe Photoshop compatible plug-ins. Currently, GraphicConverter can import 96 different graphic file formats and export 38. Conversion of several files (graphic or text) at a time is also possible through the "convert more..." feature. The tools offered for graphic editing are Photoshop-like. Detailed documentation is provided. This Macintosh shareware is provided by Lemke Software.

246

PWM converter topologies  

NASA Astrophysics Data System (ADS)

Dc to dc converters using an electrical switch to control power flow between a dc source and a dc load are discussed. Only Pulse Width Modulation (PWM) type converter topologies are considered. A basic three element, three terminal converter topology is defined followed by two universal rules allowing for derivation of a wide variety of different topologies. A summary of different topology types is provided with steady state and small signal relations given for each. The survey shows 46 converter topologies of which 18 are known and 28 are new (under, patent application). The number of topologies could be increased to 68 if negative input voltages are considered.

Meerman, E. R. W.; Spruyt, H. J. N.

1989-08-01

247

Performance study of the Bucked Coils cooling lattice for the Neutrino Factory  

NASA Astrophysics Data System (ADS)

In a Neutrino Factory (NF), neutrinos are produced from the decays of muons. The muon beam itself is produced with large emittance at the NF front-end and in order to be efficiently transported to downstream accelerator systems, the beam emittance needs to be cooled using ionisation cooling. The reference ionisation cooling channel of the NF reduces the transverse emittance by a factor of ~3. However, this lattice has a large magnetic field at the position of the RF cavities and therefore its feasibility has come under question when recent studies indicated high external magnetic field may lower the maximum achievable gradient of the RF cavities. The present work summarizes the performance of a new lattice named "Bucked Coils", designed to mitigate the magnetic field issue of the reference lattice of the NF while aiming to achieve similar cooling performance and transmission. This new lattice offers solution by reducing the longitudinal component of the magnetic field to almost 0 T while at the same time achieving a transmission comparable to the reference lattice within the transverse acceptance of 30 mm. Detailed comparison between the Bucked Coils lattice and the reference lattice of the NF follows with respect to the magnetic field reduction, cooling performance and transmission.

Alekou, A.; Pasternak, J.; Rogers, C.

2013-02-01

248

Complex brecciation and shock effects in the Buck Mountain Wash (H3-5) chondrite  

NASA Astrophysics Data System (ADS)

Buck Mountain Wash (BMW) is a new genomict breccia (H3-5) found in the Franconia (H5) strewn field in Arizona that shows complex brecciation and shock effects. It contains three distinct chondritic lithologies in sharp contact: a) a main lithology that consists primarily of petrographic type 5 material but which has finely intermixed type 3 and 4 material, b) a shock-blackened (shock stage S5) type 3 lithology (lithology A), and c) a shock-blackened type 3/4 lithology (lithology B). Buck Mountain Wash was lithified after impact-mixing and impact-melting of weakly and strongly metamorphosed materials, possibly at depth in the regolith of the parent body. Shock effects included brecciation on a fine scale, localized impact-melting of silicates, partial melting, and mobilization of metal-sulfide, and chemical fractionations that produced non-H-group composition kamacite by two disequilibrium mechanisms. Shock heating did not cause significant thermal metamorphism in the shock-blackened lithologies of BMW, except possibly in areas adjacent to whole-rock shock melt. During lithification, cooling must have been rapid at high temperatures to preserve glass and inhomogeneous silicate compositions, but not so fast at lower temperatures as to produce dendritic metal-sulfide globules or martensite.

Hutson, Melinda; Ruzicka, Alex; Pugh, Richard; Sloan, Larry; Thompson, Edwin

2007-06-01

249

Interpretation of the Perey-Buck nonlocality in terms of the relativistic optical model formalism  

SciTech Connect

Under certain conditions the solution of a nonlocal, nonrelativistic Schroedinger equation is the same as the upper component of a relativistic four-spinor which obeys a local Dirac equation. This result is obtained by combining the observation recently made by Fiedeldey and Sofianos, that a nonlocal Schroedinger equation can be transformed into a local one if a gradient term (or velocity term) is added, together with the well-known fact that the upper component of the solution of a Dirac equation also obeys a second-order equation which has a gradient term. For the case of a nonlocality of the Perey-Buck--type, the gradient term is nearly equal to the Darwin term, and hence the conditions for the validity of the relativistic-nonrelativistic equivalence are nearly valid. A numerical example is presented for the case of 21.7 MeV neutrons scattering elastically from /sup 40/Ca, for which a local relativistic optical potential has been recently obtained. The gradient term is given in terms of derivatives of the Wronskian of two independent solutions of the nonlocal equation, and numerical values for the latter are compared with the corresponding relativistic quantity. The differences are not larger than 25%. Results for the nonlocality due to exchange are also shown, and are found to be very similar to the Perey-Buck nonlocality. An implication of these results is that the relativistic optical potential may be less nonlocal than the nonrelativistic one.

Rawitscher, G.H.

1985-04-01

250

Thermionic converters for ISUS  

Microsoft Academic Search

Eight alkali metal thermionic power converters were produced for a ground-based design verification test of a bimodal power and propulsion system. The effort provided a significant development step toward a spaceflight demonstration of the Integrated Solar Upper Stage (ISUS). The converters are electrically connected in series to produce a nominal eight (8) volt, 250 Watt output. In the power mode

Edmund L. James; William D. Ramsey; Gregory J. Talbot

1997-01-01

251

Analog to Digital Converter.  

National Technical Information Service (NTIS)

An analog-to-digital converters, finding particular application in a multichannel pulse height analyzer, with a means for digitizing the analog input in two conversion steps is presented. To digitize the input to 13 bits, a 7-bit digital to analog convert...

C. H. Lucas

1974-01-01

252

Respectful Type Converters  

Microsoft Academic Search

In converting an object of one type to another, we expect some of the original object's behavior to remain the same and some to change. How can we state the relationship between the original object and converted object to characterize what information is preserved and what is lost after the conversion takes place? We answer this question by introducing the

Jeannette M. Wing; John Ockerbloom

2000-01-01

253

Diodes as pseudo-active elements in high-frequency dc/dc converters  

NASA Astrophysics Data System (ADS)

A novel approach to realizing zero-voltage switching in high-frequency dc/dc converters is presented. Utilizing the parasitic associated with the diode stored charge, it is shown that the diode reverse current established for charge removal can be used advantageously to accomplish soft switching. The entire family of single-transistor dc/dc converters can be realized using the technique. The converter topologies are seen to differ from their hard-switched counterparts only by the presence of a resonant capacitor. It is also shown that device and component stresses are moderate as compared to existing quasi-resonant and resonant techniques. Converter analysis is rather complex as a result of the dominant diode nonlinearities, and no closed-form expressions are possible. Converter transfer characteristics are obtained through simulation, and operating limits are analytically obtained. The concept is validated by experimental results using buck-type converters rated at approximately 100 W and operating at frequencies around 1 MHz.

Divan, Deepakraj M.

1989-01-01

254

The Economic Impact of Bucks County Community College on the Local Economy During Fiscal Year 1978-79.  

ERIC Educational Resources Information Center

The effects of Bucks County Community College (BCCC) on the local economy during fiscal year (FY) 1979 were investigated in terms of the monies spent in operating BCCC through purchases of goods and services, salaries to college employees, student financial aid expenditures, veterans' benefits, and property taxes paid by college employees, as well…

Mahon, Jack

255

Improving Fruit and Vegetable Consumption Among Low-Income Customers at Farmers Markets: Philly Food Bucks, Philadelphia, Pennsylvania, 2011  

PubMed Central

Introduction We evaluated whether Philly Food Bucks, a bonus incentive program at farmers markets, is associated with increased fruit and vegetable consumption and Supplemental Nutrition Assistance Program (SNAP) sales at farmers markets in low-income areas. Methods A convenience sample of 662 customers at 22 farmers markets in low-income neighborhoods in Philadelphia, Pennsylvania, was surveyed via face-to-face interviews. Questions addressed shopping characteristics, self-reported change in fruit and vegetable consumption, whether customers tried new fruits or vegetables, use of Philly Food Bucks, and demographic information. Market-level SNAP sales and Philly Food Bucks redemption data were also collected to monitor sales patterns. Results Philly Food Bucks users were significantly more likely than nonusers to report increasing fruit and vegetable consumption (OR, 2.4; 95% CI, 1.6–3.7; P < .001) and to report trying new fruits or vegetables (OR 1.8; 95% CI, 1.2–2.7; P = .006). At the market level, average SNAP sales more than doubled at farmers markets in low-income areas in the first 2 years of the Philly Food Bucks program. At the city’s largest farmers market in a low-income area, the program was associated with an almost 5-fold higher increase in annual SNAP sales compared with baseline. Conclusion Results from this study demonstrate that a bonus incentive program tied to SNAP was associated with self-reported increases in fruit and vegetable consumption and increased SNAP sales at participating farmers markets in low-income communities. More research is warranted to evaluate the long-term impact of bonus incentives on farmers market use, dietary behaviors, and health outcomes.

Aquilante, Jennifer L.; Solomon, Sara; Colby, Lisa; Kawinzi, Mukethe A.; Uy, Nicky; Mallya, Giridhar

2013-01-01

256

Catalytic converter efficiency monitoring  

SciTech Connect

This patent describes a method for monitoring an internal combustion engine on-board catalytic converter efficiency. It comprises: establishing predetermined test entry conditions; transferring fuel control system input to an EGO sensor located downstream of a converter; measuring a characteristic of a first air/fuel ratio limit cycle with a first set of fuel controller parameters; changing fuel controller parameters; measuring a characteristic of a second air/fuel ratio limit cycle with a second set of fuel controller parameters; calculating a transport time delay and a time constant of a converter as a function of the first and second limit cycles; and determining catalytic converter efficiency from a predetermined catalytic efficiency characterized as a function of a transport time delay and a time constant.

Gopp, A.Y.

1992-10-27

257

Template Converter Program.  

National Technical Information Service (NTIS)

The computer program represents one of three FORTRAN IV programs necessary to generate perspective views of highways from design data. The Template Converter Program performs essentially a bookkeeping function for the Perspective Plot Program. It accepts ...

J. P. Penzien

1971-01-01

258

Wirephoto Standards Converter.  

National Technical Information Service (NTIS)

A standards converter that translates simultaneously between the United States and European wirephoto networks has been developed. Items of noncompatibility include picture duration, lines per minute, lines per inch, and scanning direction. The system ope...

D. E. Troxel W. F. Schreiber C. L. Seitz

1968-01-01

259

Cascaded thermionic converters  

NASA Astrophysics Data System (ADS)

A combination of experimental results and analytical work indicates the feasibility of a cascaded thermionic converter comprised of a barium-cesium stage with an emitter temperature of 2000 K and a cesium close-spaced stage with a collector temperature of 740 K having an overall lead efficiency of 27%. This cascaded converter has potential beneficial applications to space nuclear power, space terrestrial solar power and topping cycles in fossil or nuclear central stations.

Fitzpatrick, Gary O.; Allen, Daniel T.; McVey, John B.

1992-01-01

260

PDF to HTML Converter  

NSDL National Science Digital Library

If you're looking for a way to convert pdf files to html, this helpful application can do just that. Visitors just need to click the browse button here to locate the pdf that they wish to transfer. After doing this, they will supply their own email, and seconds later, they will have the converted file. This version is compatible with all operating systems.

2010-01-01

261

Analog to digital converter  

Microsoft Academic Search

An analog-to-digital converter, finding particular application in a multichannel pulse height analyzer, includes means for digitizing the analog input in two conversion steps. To digitize the input to 13 bits, a 7-bit digital to analog converter with a 7-bit up-down counter is used. During the first conversion step which is a coarse conversion, the input V sub i is compared

C. H. Lucas

1976-01-01

262

[Pearl S. Buck, Literature Nobel Price, and phenylketonuria: a moving relationship].  

PubMed

Art and Medicine, in some occasions have singular contact points. An example of this is the life of the North American writer Pearl S. Buck, a Litterature Nobel Prize winner in 1938, and her relation with phenylketonuria and mental retardation. The present paper is a biographical sketch of this brilliant writer, whose only daughter had phenylketonuria, an inborn error of metabolism of low frequency. If this disease is not treated, it may cause mental retardation. At the same time, we point out some of the highlights of the discovery of this disorder in Norway in 1934, and the description of its first treatment in 1953. At the present time, the mental retardation that this disease causes, can be prevented by means of the neonatal screening. PMID:11921532

Vela Amieva, M

263

High performance ripple feedback for the buck unity-power-factor rectifier  

SciTech Connect

The buck unity-power-factor rectifier has harmonic-free input current with complete load regulation down to zero output voltage. A new ``nonlinear ripple feedback`` is proposed which exactly cancels the spoiling effect of dc-side current ripple on the low-distortion ac line current waveforms, even for large amounts of ripple. This cancellation is independent of operating point and readily implemented with analog hardware, thereby permitting economies in the design of the dc filter while maintaining harmonic-free operation. Both large-signal and incremental analyses of the rectifier are given. Confirming experimental results from a 1-kW 48-V isolated battery charger operating with current-ripple levels ranging from 50% to discontinuous-conduction-mode operation are given.

Lo, Y.W.; King, R.J. [Univ. of Toledo, OH (United States). Dept. of Electrical Engineering

1995-03-01

264

Performance of a Voltage Step-Up/Step-Down Transformerless DC/DC Converter: Analytical Model  

NASA Astrophysics Data System (ADS)

The authors present an analytical model for a voltage step-up/step-down DC/DC converter without transformers. The proposed topology is a combination of classic buck and boost converters in one single circuit but with differing operational principles. The converter is developed for a wind power autonomous supply system equipped with a hydrogen electrolytic tank and a fuel cell for energy stabilization. The main power source of the hydrogen-based autonomous supply system is energized by a synchronous generator operating on permanent magnets and equipped with a diode bridge. The input voltage of the converter in this case varies in the range 0-700 V, while its output DC voltage must be 540 V according to the demand of other parts of the system. To maintain the rated voltage, a special electrical load regulation is introduced. The calculations of the converter, the generator (equipped with a diode bridge) as element of the power system supply joint, and the load replaced by resistance are verified with PSIM software.

Suskis, P.; Rankis, I.

2012-01-01

265

Vector generator scan converter  

DOEpatents

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

Moore, J.M.; Leighton, J.F.

1988-02-05

266

The Impact of New York City's Health Bucks Program on Electronic Benefit Transfer Spending at Farmers Markets, 2006-2009  

PubMed Central

Introduction Increasing the accessibility and affordability of fresh produce is an important strategy for municipalities combatting obesity and related health conditions. Farmers markets offer a promising venue for intervention in urban settings, and in recent years, an increasing number of programs have provided financial incentives to Supplemental Nutrition Assistance Program (SNAP) recipients. However, few studies have explored the impact of these programs on use of SNAP benefits at farmers markets. Methods New York City’s Health Bucks Program provides SNAP recipients with a $2 coupon for every $5 spent using SNAP benefits at participating farmers markets. We analyzed approximately 4 years of electronic benefit transfer (EBT) sales data, from July 2006 through November 2009, to develop a preliminary assessment of the effect of the Health Bucks Program on EBT spending at participating markets. Results Farmers markets that offered Health Bucks coupons to SNAP recipients averaged higher daily EBT sales than markets without the incentive ($383.07, 95% confidence interval [CI], 333.1–433.1, vs $273.97, 95% CI, 243.4–304.5, P < 0.001) following the introduction of a direct point-of-purchase incentive. Multivariate analysis indicated this difference remained after adjusting for the year the market was held and the neighborhood poverty level. Conclusion When a $2 financial incentive was distributed with EBT, use of SNAP benefits increased at participating New York City farmers markets. We encourage other urban jurisdictions to consider adapting the Health Bucks Program to encourage low-income shoppers to purchase fresh produce as one potential strategy in a comprehensive approach to increasing healthful food access and affordability in low-income neighborhoods.

Dunn, Lillian; Nonas, Cathy; Dannefer, Rachel; Sacks, Rachel

2013-01-01

267

Fluorometer to spectrophotometer converter  

Microsoft Academic Search

A simple accessory has been constructed that will convert a standard laboratory spectrofluorometer into a spectrophotometer. This attachment fits within the sample compartment of a spectrofluorometer and consists of a cuvette holder, two mirrors, and two collimators. Light is redirected from the excitation lamp through the cuvette and then into the emission detector to measure absorbance instead of fluorescence. One

H. R. Garner

1996-01-01

268

Fiber optic power converter  

NASA Astrophysics Data System (ADS)

High-efficiency, narrow-band fiber optic power converters have been produced under pilot line conditions. Power conversion efficiencies as high as 30 percent are obtained for devices illuminated with 50 mw from a 1060 nm Nd:YAG laser. The devices have an average power conversion efficiency in excess of 23 percent and fill factor greater than 74 percent. These devices can be used in remote locations to provide power for a variety of uses.

Eide, John; Mueller, Chip; Leonard, Ted

1989-09-01

269

Purplemath: Cancelling / Converting Units  

NSDL National Science Digital Library

This page contains a step-by-step tutorial in converting between units. It begins with one-step conversions, progressing to problems requiring multiple unit conversion. Areas of frequent student difficulty are given extra attention by the author, who presents the tutorial in an informal writing style designed to engage high school students. This tutorial is part of an award-winning collection of free resources developed to promote understanding and confidence in algebra.

Stapel, Elizabeth

270

Free FLV Converter  

NSDL National Science Digital Library

Taking Flash files from the web can be a bit cumbersome, so this application will definitely be a most welcome find. This free Flash converter (the second to last link on the left) allows users to take Flash files and transfer them to formats appropriate for portable devices and other items. The site is available in both French and English and this particular version is compatible with computers running Windows 2000, XP, 2003, and Vista.

2007-01-01

271

Electrothermodynamic (etd) power converter  

Microsoft Academic Search

These inventions relate to novel advances in Electrothermodynamics (ETD), also known as charged aerosol, heat\\/electric power generators: (1) A new more efficient, compact converging\\/diverging configuration comprising a torus of revolution (TORON) used with a gas flywheel. (2) A ''Method II'' two-fluid mixed flow ejector\\/converter in a gas flywheel loop employing a primary steam or a high molecular weight driver jet

1983-01-01

272

Multilevel converters -- A new breed of power converters  

SciTech Connect

Multilevel voltage source converters are emerging as a new breed of power converter options for high-power applications. The multilevel voltage source converters typically synthesize the staircase voltage wave from several levels of dc capacitor voltages. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. The techniques to balance the voltage between different levels normally involve voltage clamping or capacitor charge control. There are several ways of implementing voltage balance in multilevel converters. Without considering the traditional magnetic coupled converters, this paper presents three recently developed multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded-inverters with separate dc sources. The operating principle, features, constraints, and potential applications of these converters will be discussed.

Lai, J.S. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.; Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

1995-09-01

273

Ecology of juvenile hawksbills (Eretmochelys imbricata) at Buck Island Reef National Monument, US Virgin Islands  

USGS Publications Warehouse

Surveys of juvenile hawksbills around Buck Island Reef National Monument, US Virgin Islands from 1994 to 1999 revealed distributional patterns and resulted in a total of 75 individual hawksbill captures from all years; turtles ranged from 23.2 to 77.7 cm curved carapace length (CCL; mean 42.1 ± 12.3 cm SD). Juveniles concentrated where Zoanthid cover was highest. Length of time between recaptures, or presumed minimum site residency, ranged from 59 to 1,396 days (mean 620.8 ± 402.4 days SD). Growth rates for 23 juveniles ranged from 0.0 to 9.5 cm year?1 (mean 4.1 ± 2.4 cm year?1SD). Annual mean growth rates were non-monotonic, with the largest mean growth rate occurring in the 30–39 cm CCL size class. Gastric lavages indicated that Zoanthids were the primary food source for hawksbills. These results contribute to our understanding of juvenile hawksbill ecology and serve as a baseline for future studies or inventories of hawksbills in the Caribbean.

Hart, Kristen M.; Sartain, Autumn R.; Hillis-Starr, Zandy-Marie; Phillips, Brendalee; Mayor, Philippe A.; Roberson, Kimberly; Pemberton, Roy A., Jr.; Allen, Jason B.; Lundgren, Ian; Musick, Susanna

2013-01-01

274

Experimental analysis of a DC bucking motor blocking geomagnetically induced currents  

SciTech Connect

An experimental study investigates the performance of a dc bucking motor for the blocking of geomagnetically induced currents (GICs) within a 3 kVA/416 V three-phase distribution feeder. This blocking method consists of connecting a separately excited dc motor between neutral and ground of a Y-grounded transformer consisting of a bank of three single-phase transformers. Losses and currents of the transformer and the blocking device are measured at no-load, rated-load, unbalanced-load and line-to-neutral short circuit conditions without and with GICs. Thereafter, the dc, ac and total [lambda]-i characteristics of one single-phase transformer of the above-mentioned transformer bank are simultaneously measured using an arbitrary waveform generator, a power amplifier and a digital data acquisition network. These [lambda]-i characteristics -- where the dc bias current is a parameter -- are then used to model a single-phase transformer under dc bias current conditions (e.g., assumed GICs) and to calculate voltages and currents of a single-phase transformer when subjected to GICs. The simulated signals are then compared with measured time functions.

Fardoun, A.A.; Fuchs, E.F.; Masoum, M.A.S. (Univ. of Colorado, Boulder, CO (United States). Dept. of Electrical and Computer Engineering)

1994-01-01

275

Thyristor converter simulation and analysis.  

National Technical Information Service (NTIS)

In this paper we present a simulation on thyristor converters. The simulation features nonlinearity, non-uniform firing, and the commutations. Several applications such as a current regulation, a converter frequency characteristics analysis, and a power l...

S. Y. Zhang

1991-01-01

276

Electrothermodynamic (etd) power converter  

SciTech Connect

These inventions relate to novel advances in Electrothermodynamics (ETD), also known as charged aerosol, heat/electric power generators: (1) A new more efficient, compact converging/diverging configuration comprising a torus of revolution (TORON) used with a gas flywheel. (2) A ''Method II'' two-fluid mixed flow ejector/converter in a gas flywheel loop employing a primary steam or a high molecular weight driver jet such as a fluorocarbon containing charged aerosol water droplets and a low molecular weight carrier gas such as hydrogen or helium with an electro-negative gas additive, in a Rankine cycle including a vapor/gas and liquid separator with a bypass to the ejector/converter loop. (3) A ''Method III'' two-fluid mixed flow comprising a supersonic jet expanding conically within a subsonic flow, separated by a boundary layer in which the charged aerosol forms downstream of the orifice, at a cross section of at least 100 times the orifice section; and in which the electric charge density of the charged aerosol decreases along the jet axis, whereby substantially all of the kinetic power of the jet is converted to electric power within the jet, there being no ejector. (4) An array of supersonic jets utilizing Method III. (5) An array of supersonic jets utilizing Method III without separating duct walls in which ''convection cells'' provide return flows, forming a plurality of TORON configurations. (6) A supercritical Rankline cycle in a single stage employing Method III. (7) A method IV two-fluid cycle uses charged aerosols in an inert gas and operates on an Ericsson-type cycle. (8) Optimum operating conditions are defined for Methods II, III, and IV. (9) A high potential emitter is employed with a grounded body, and a sapphire tube sealed to metal by a new technique provides an insulating duct for the high temperature, high pressure vapor.

Marks, A.M.

1983-07-26

277

Unidirectional energy converter  

SciTech Connect

Thermal energy is converted into rotational energy by using the expansion of a fluid medium to propel a plurality of pistons within at least one continuous, closed-loop passageway mounted on a rotatable platform. In at least one region of the passageway, the pistons must move inwardly against centrifugal force as the platform rotates. In at least one other region of the passageway, the pistons are moved outwardly under the influence of centrifugal force. Means are provided for imparting force to successive ones of the pistons to propel them against centrifugal force in said one region; while means are provided for converting the energy of pistons moving outwardly under the influence of centrifugal force in said other region into rotational energy. This rotational energy is used to drive gears mounted on the platform which mesh with a stationary gear carried beneath the platform to cause rotation of the platform about its rotational axis. The energy used to accelerate the pistons is thereby converted into rotational energy of the platform. In one embodiment of the invention, at least two continuous, closed-loop passageways are used on the platform in order to prevent an unbalanced condition. In another embodiment of the invention, a single passageway is used on the platform comprising two essentially straight portions on opposite sides of the axis of rotation of the platform interconnected at their opposite ends by curved portions, also on opposite sides of the axis of rotation of the platform. By forcibly rotating the platform in reverse, the invention can be used as a compressor.

Anno, J.N.; Fawcett, S.L.

1981-07-28

278

Plastic molded torque converter turbine  

Microsoft Academic Search

A turbine disposed within a torque converter is described, the torque converter disposed between an engine and a transmission within a vehicle, the turbine rotatively fixed to a converter output element, the turbine comprising: a hub, formed of ferrous material, including: a flange portion, having a first side and a second side, having a complement of projections protruding from the

R. R; T. E. Hojna

1993-01-01

279

Rupee Convertibility and Exit Policy  

Microsoft Academic Search

The successful of partial convertibility of rupee and adequate foreign reserves have boosted confidence of the government. It is more than likely that we are going to see a convertible rupee on trade account before the end of this year. In official quarters it is believed that fiscal imbalance is only stumbling block in the path of a fully convertible

Rastogi A B

280

164 Currencies Converter  

NSDL National Science Digital Library

Olsen and Associates of Zurich, Switzerland, a "developer of online forecasting technology for business and finance" has made this simple and fun service available. Simply enter the amount of currency for any of 164 currencies, the currency to be converted to, and the date of the exchange rate (back to January 1, 1990, in day/month/year format) into an online form, and presto, an exchange rate (which is then reversible) is obtained. As this is a demonstration product, neither multiple currencies nor multiple dates are allowed. Users should also read the FAQ to understand why the rate they get might be slightly different from the one their bank advertises.

1997-01-01

281

Cycloidal Wave Energy Converter  

SciTech Connect

This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

Stefan G. Siegel, Ph.D.

2012-11-30

282

Series Connected Buck Boost Regulator Concept for High Efficiency Light Weight DC Voltage Regulation.  

National Technical Information Service (NTIS)

Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Bo...

A. G. Birchenough

2003-01-01

283

Converting Biomass to Products  

SciTech Connect

For nearly 30 years, PNNL has been developing and applying novel thermal, chemical and biological processes to convert biomass to industrial and consumer products, fuels and energy. Honors for technologies resulting from this research include the Presidential Green Chemistry Award and several Federal Laboratory Consortium and R&D 100 Awards. PNNL’s research and development activities address the complete processing scheme, from feedstock pretreatment to purified product recovery. The laboratory applies fundamental science and advanced engineering capabilities to biomass conversion and processing to ensure effective recovery of optimal value from biomass; carbohydrate polymer systems to maximize energy efficiencies; and micro-technology systems for separation and conversion processes. For example, bioproducts researchers in the laboratory’s Institute for Interfacial Catalysis develop and demonstrate the utility of new catalyst formulations for production of bio-based chemicals. This article describes a sampling of current and recent catalysis projects for biomass conversion.

Graybeal, Judith W.

2006-06-01

284

A Comparison Between the GPI and PID Controllers for the Stabilization of a DC–DC “BuckConverter: A Field Programmable Gate Array Implementation  

Microsoft Academic Search

This paper presents a comparison between two sta- bilizing average output feedback controllers implemented on a field programmable gate array (FPGA) facility. A generalized proportional integral (GPI) controller and a proportional integral derivative (PID) controller are implemented using an FPGA, and their respective performances are duly compared. The GPI con- troller is found to present a better dynamic response than

Eric William Zurita-Bustamante; Jesús Linares-Flores; Enrique Guzman-Ramirez; Hebertt Sira-Ramirez

2011-01-01

285

High intensity solar energy converter  

Microsoft Academic Search

A photovoltaic energy converter is described for converting incident radiant energy, such as solar energy, to electrical energy. The converter comprises a cell formed from integrally interconnected p-n junction-containing semiconductor wafers. The wafers are stacked end-to-end so that the respective junctions in each wafer are parallel to each other. The efficiency and performance of the cell is improved, upon exposure

R. E. House; R. A. Irvin; D. F. Kane

1978-01-01

286

A ZCS bidirectional flyback converter  

Microsoft Academic Search

This paper addresses the design and analysis of a zero-current-switched (ZCS) bi-directional flyback dc\\/dc converter. The converter is based on extending a previously developed unidirectional ZCS flyback converter and replacing the output diode with a controlled switch, which acts as either a rectifier or a power control switch in the corresponding power flow direction. By adding an auxiliary winding in

H. S. H. Chung; Wai-leung Cheung; Kam-shing Tang

2004-01-01

287

Indian Converts Collection  

NSDL National Science Digital Library

First published in 1727, the remarkable book "Indian Converts, or Some account of the lives and dying speeches of a considerable number of the Christianized Indians of Martha's Vineyard" is now available in full online. Written by Experience Mayhew, the book provides remarkable insights into the lives and culture of four generations of Native Americans in colonial America. This digitized version was created at Reed College, and visitors can look through all four sections of the work, which include "Indian Ministers" and "Pious Children." Throughout the work, Mayhew details the books that different age groups were reading, provides insights into early New England pedagogy and childrearing practices, and also describes each individual in terms of their own genealogy and personal history. The truly fantastic thing about the site is that it also contains an archive with over 600 images and documents that further contextualize the work. Also, the site contains study guides designed for classroom use that cover artifact analysis, genealogy, and reading gravestones.

288

Potential for conversion to coal as a fuel by major fuel users in the Pennsylvania counties of Bucks, Chester, Delaware, Montgomery and Philadelphia  

Microsoft Academic Search

Major fuel users in the Pennsylvania counties of Bucks, Chester, Delaware, Montgomery and Philadelphia are identified. Their present fuel use is discussed and the potential for their conversion from oil and gas to coal as fuel is briefly assessed. Impacts on air quality and freight rail needs are also reviewed. Finally, the attitudes of these industries toward conversion is discussed,

C. R. Roxin; M. Tinkleman

1974-01-01

289

Potential for conversion to coal as a fuel by major fuel users in the Pennsylvania counties of Bucks, Chester, Delaware, Montgomery, and Philadelphia. Final report  

Microsoft Academic Search

This report identifies major fuel users in the Pennsylvania counties of Bucks, Chester, Delaware, Montgomery and Philadelphia. Their present fuel use is discussed and the potential for their conversion from oil and gas to coal as fuel is briefly assessed. Impacts on air quality and freight rail needs are also reviewed. Finally, the attitudes of these industries toward conversion is

C. L. Roxin; M. Tinkleman

1974-01-01

290

A study of the Kent and Buck screen tests of mental ability in relation to Otis and Stanford Achievement Test scores  

Microsoft Academic Search

100 first offenders admitted to a federal correctional institution for boys were given the Kent Oral Emergency Test, the Buck Time Appreciation Test, the Otis Group Intelligence Scale, Advanced Examination, and the Stanford Achievement Test. The screen tests were highly related to each other and to the Otis. Of the 2 screen tests, the Kent test (Scale D) seemed less

Charles N. Cofer; Mark M. Biegel

1948-01-01

291

Distribution of caprine arthritis encephalitis virus provirus, RNA, and antigen in the reproductive tract of one naturally and seven experimentally infected bucks.  

PubMed

Caprine arthritis encephalitis is a worldwide, multisystemic disease caused by a small ruminant lentivirus. Although the main route of transmission is oral, detection of proviral DNA of the caprine arthritis encephalitis virus (CAEV) in caprine semen has been previously described. However, the presence of viral antigens in the male reproductive tract has apparently never been reported. The objective was to study lesions in the buck reproductive system and to detect, in these tissues, the presence of proviral DNA, viral RNA and CAEV antigens. Tissues from eight CAEV-infected bucks (one naturally and seven experimentally infected) were analyzed by histopathology, nested polymerase chain reaction, reverse transcriptase-polymerase chain reaction, and immunohistochemistry. Interstitial pneumonia, synovitis, and lesions in the male reproductive tract were detected in some of the bucks. Proviral DNA was detected in the lungs and joints as well as in the reproductive systems of all animals, whereas viral RNA was detected only in the genital tract of the naturally infected buck. Viral antigens were immunostained in most of the organs of the male reproductive tract. This report was apparently the first to clearly demonstrate CAEV antigen expression in the male reproductive tract, which indicates the possibility of venereal transmission of CAEV. PMID:23973050

Turchetti, Andréia P; Paniago, Juliana J; da Costa, Luciana F; da Cruz, Juliano C M; Braz, Gissandra F; Gouveia, Aurora M G; Paixão, Tatiane A; Santos, Renato L; Heinemann, Marcos B

2013-08-20

292

Matrix converters: a technology review  

Microsoft Academic Search

The matrix converter is an array of controlled semiconductor switches that connects directly the three-phase source to the three-phase load. This converter has several attractive features that have been investigated in the last two decades. In the last few years, an increase in research work has been observed, bringing this topology closer to the industrial application. This paper presents the

Patrick W. Wheeler; José Rodríguez; Jon C. Clare; Lee Empringham; Alejandro Weinstein

2002-01-01

293

Thyristor converter simulation and analysis  

NASA Astrophysics Data System (ADS)

In this paper we present a simulation on thyristor converters. The simulation features nonlinearity, non-uniform firing, and the commutations. Several applications such as a current regulation, a converter frequency characteristics analysis, and a power line disturbance analysis will be presented.

Zhang, S. Y.

1991-05-01

294

The Angiotensin I Converting Enzyme.  

National Technical Information Service (NTIS)

The angiotensin I converting enzyme (kininase II; peptidyl dipeptidase; EC 3.4. 15.1) has a dual function: it converts angiotensin I to angiotensin II and it inactivates bradykinin. Lung, kidney, guinea pig plasma and testicles are among the richest sourc...

E. G. Erdos

1977-01-01

295

High Efficiency Flyback Converter Technology  

Microsoft Academic Search

Technologies are discussed to realize a DC\\/DC Flyback converter with high power conversion efficiency. The focus is on efficiency because of its high value in the application to process electricity generated by photovoltaic modules. Experiments with a 200 W active-clamped bidirectional Flyback converter prototype demonstrate power train efficiencies above 90% between 10% and 100% of the rated power and peak

U. Boeke

2007-01-01

296

High power density dc-to-dc converters for aerospace applications  

NASA Astrophysics Data System (ADS)

Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.

Divan, Deepakraj M.

1990-12-01

297

A Multichannel Airborne Coding Converter.  

National Technical Information Service (NTIS)

The paper describes an eight-channel aircraft coding converter designed for conversion of signals from transducers sensing pulsation meteorological parameters to a form suitable for subsequent magnetic recording. (Author)

N. K. Vinnichenko G. N. Shur

1967-01-01

298

Thermionic-photovoltaic energy converter  

SciTech Connect

A thermionic-photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or galium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

Chubb, D. L.

1985-07-09

299

Radiation tolerant power converter controls  

NASA Astrophysics Data System (ADS)

The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to significantly increased radiation induced effects in materials close to the accelerator, including the FGC. Recent radiation tests indicate that the current FGC would not be sufficiently reliable. A so-called FGClite is being designed to work reliably in the radiation environment in the post-LS1 era. This paper outlines the concepts of power converter controls for machines such as the LHC, introduces the risks related to radiation and a radiation tolerant project flow. The FGClite is then described, with its key concepts and challenges: aiming for high reliability in a radiation field.

Todd, B.; Dinius, A.; King, Q.; Uznanski, S.

2012-11-01

300

Digitally corrected multi-bit ?? data converters  

Microsoft Academic Search

?? data converters using multibit internal A\\/D and D\\/A converters (noise-shaping converters) have lower quantization noise and are more stable than the usual single-bit systems. However, the required linearity of the internal multibit digital-to-analog converter (DAC) is very difficult to achieve for an untrimmed integrated converter. A description is given of several novel multibit ?? converters which use digital correction

T. Cataltepe; A. R. Kramer; L. E. Larson; G. C. Temes; R. H. Walden

1989-01-01

301

High Efficiency RFID UHF Power Converter  

Microsoft Academic Search

The paper proposes a high efficiency RFID UHF power converter unit to overcome the low efficiency problem. This power converter is mainly composed of an RF-DC converter and a DC-DC converter. In order to overcome the low efficiency problem in low current consuming condition, a DC-DC converter is added to conventional single RF-DC converter rectifier to increase the rectifying efficiency

Zhou Shenghua; Yang Zhichao; Wu Nanjian

2006-01-01

302

Residence time, chemical and isotopic analysis of nitrate in the groundwater and surface water of a small agricultural watershed in the Coastal Plain, Bucks Branch, Sussex County, Delaware  

USGS Publications Warehouse

Nitrate is a common contaminant in groundwater and surface water throughout the Nation, and water-resource managers need more detailed small-scale watershed research to guide conservation efforts aimed at improving water quality. Concentrations of nitrate in Bucks Branch are among the highest in the state of Delaware and a scientific investigation was performed to provide water-quality information to assist with the management of agriculture and water resources. A combination of major-ion chemistry, nitrogen isotopic composition and age-dating techniques was used to estimate the residence time and provide a chemical and isotopic analysis of nitrate in the groundwater in the surficial aquifer of the Bucks Branch watershed in Sussex County, Delaware. The land use was more than 90 percent agricultural and most nitrogen inputs were from manure and fertilizer. The apparent median age of sampled groundwater is 18 years and the estimated residence time of groundwater contributing to the streamflow for the entire Bucks Branch watershed at the outlet is approximately 19 years. Concentrations of nitrate exceeded the U.S. Environmental Protection Agency drinking-water standard of 10 milligrams per liter (as nitrogen) in 60 percent of groundwater samples and 42 percent of surface-water samples. The overall geochemistry in the Bucks Branch watershed indicates that agriculture is the predominant source of nitrate contamination and the observed patterns in major-ion chemistry are similar to those observed in other studies on the Mid-Atlantic Coastal Plain. The pattern of enrichment in nitrogen and oxygen isotopes (?15N and ?18O) of nitrate in groundwater and surface water indicates there is some loss of nitrate through denitrification, but this process is not sufficient to remove all of the nitrate from groundwater discharging to streams, and concentrations of nitrate in streams remain elevated.

Clune, John W.; Denver, Judith M.

2012-01-01

303

Early Archaean hydrothermal fluids; a study of inclusions from the ? 3.4 Ga Buck Ridge Chert, Barberton Greenstone Belt, South Africa  

Microsoft Academic Search

Fluid inclusions have been studied from cavities and breccias in one of the oldest well-preserved, relatively low-grade metamorphosed sedimentary sequences on Earth. The fluid inclusion-bearing samples are from the uppermost part of the early Archaean (?3.4 Ga) Buck Ridge volcano-sedimentary complex in the Barberton Greenstone Belt (South Africa), which was affected by hydrothermal alteration during and immediately after its deposition. In

Sjoukje T. de Vries; Jacques L. R. Touret

2007-01-01

304

Parallel Connection of Two Three-Phase Three-Switch Buck-Type Unity-Power-Factor Rectifier Systems With DC-Link Current Balancing  

Microsoft Academic Search

Connecting three-phase rectifier systems in parallel shows many advantages as compared to a single rectifier system with higher output power, such as higher reliability, smaller current and voltage ripple components, lower filtering effort, or higher system bandwidth. However, current unbalance or circulating currents can occur for modular design. In this paper, the parallel connection of two three-phase three-switch buck-type unity-power-factor

Martina Baumann; Johann W. Kolar

2007-01-01

305

Automotive catalytic converter exhaust system  

SciTech Connect

Disclosed is a vehicle exhaust system containing a three-way catalytic converter. An insulated flexible duct connects the outlet of the engine exhaust manifold with the inlet of the three-way catalytic converter to retain the exhaust engine gases at a temperature greater than the ignition temperature of the threeway catalyst in the catalytic converter. The insulated flexible duct is preferably made of an inner flexible metal conduit surrounded by fibrous insulation which in turn is surrounded on the outside by a second flexible metal conduit. The system is economical, contains no active elements which would require maintenance or could get out of order, is adaptable to motor vehicles of all types (especially automobiles, light trucks and vans) including those powered by either gasoline and diesel engines and entirely eliminates the need for expensive and complicated light-off catalysts in the system.

Pallo, J.M.; Previte, S.J.; Schafer, W.

1982-08-24

306

Topological constraints on basic PWM converters  

NASA Astrophysics Data System (ADS)

A modeling and synthesis technique is introduced for single-ended ladder-structured dc-dc converter topologies. Topological constraints are derived that enhance the understanding of structural properties of converter circuits and clarify the roles of inductors and capacitors in various converters using magnetic or capacitive energy storage/transfer mechanisms. The exact duality relationships among the basic converter topologies are established.

Liu, Kwang-Hwa; Lee, Fred C.

307

Multilevel converters for power system applications  

SciTech Connect

Multilevel converters are emerging as a new breed of power converter options for power system applications. These converters are most suitable for high voltage high power applications because they connect devices in series without the need for component matching. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. To avoid voltage unbalance between different levels, several techniques have been proposed for different applications. Excluding magnetic-coupled converters, this paper introduces three multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded inverters with separate dc sources. The operation principle, features, constraints, and potential applications of these converters will be discussed.

Lai, J.S.; Stovall, J.P. [Oak Ridge National Lab., TN (United States); Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

1995-09-01

308

Half-Bridge Type Immittance Converter  

NASA Astrophysics Data System (ADS)

The immittance converter has the input impedance that is proportional to the admittance of the load connected across output terminals. Therefore, in this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant voltage source into a constant current source and a constant current source into a constant voltage source. In this paper, we propose a new type immittance converter, named half-bridge type immittance converter, consists of a tapped transformer and a pair of L, C. The new immittance converter is developed from the hybrid type immittance converter, and has almost same characteristics of that.

Irie, Hisaichi; Takayama, Nobuyuki

309

CONVERTING ABANDONED LANDS TO CROPLAND  

Technology Transfer Automated Retrieval System (TEKTRAN)

Because of economic conditions, areas of cropland in Ukraine have been left unused for several years. These abandoned lands are now infested with perennial weeds. Producers are interested in converting these lands back to cropland with no-till systems to preserve soil benefits gained by not tillin...

310

A novel interferometric wavelength converter  

Microsoft Academic Search

The fiber Kerr effect employment in a wavelength conversion version, owing to low silica nonlinearity, has been prevented by the lack of an efficient interferometric architecture. A novel all-fiber wavelength converter is presented and characterized. The proposed scheme while taking advantage of the Kerr effect properties in standard communication optical fiber overcomes classical interferometric structure limitations, such as high environmental

Pierpaolo Boffi; Lucia Marazzi; Mario Martinelli

1999-01-01

311

Tactical Data Converter Design Study.  

National Technical Information Service (NTIS)

The report contains the studies performed and the systems analysis used to provide design data necessary for construction of a tactically-oriented digital-to-video converter. This study was conducted in two parts: the first was an investigation into the v...

A. W. Brown A. B. Cohen G. G. Strohmeyer

1969-01-01

312

Sea water battery power converter  

Microsoft Academic Search

The invention converts the voltage output of a DC source to a higher voltage. A germanium transistor start-up circuit receives a DC supply voltage input and includes an astable multivibrator which produces a square wave voltage output that is transformed to a substantially DC steady-state voltage output by a transformer and a capacitor. This elevated voltage is provided to an

Russell E. Hammond; John L. Henry

1991-01-01

313

Wide-load-range resonant converter supplying the SAE J-1773 electric vehicle inductive charging interface  

SciTech Connect

The recommended practice for electric vehicle battery charging using inductive coupling (SAE J-1773), published in January 1995 by the Society of Automotive Engineers, Inc., outlines values and tolerances for critical vehicle inlet parameters which must be considered when selecting a coupler driving topology. The inductive coupling vehicle inlet contains a significant discrete capacitive component in addition to low magnetizing and high leakage inductances. Driving the vehicle interface with a variable-frequency series-resonant converter results in a four-element topology with many desirable features: unity transformer turns ratio; buck/boost voltage gain; current-source operation; monotonic power transfer characteristic over a wide load range; throttling capability down to no load; high-frequency operation; narrow modulation frequency range; use of zero-voltage-switched MOSFET's with slow integral diodes; high efficiency; inherent short-circuit protection; soft recovery of output rectifiers and secondary dv/dt control and current waveshaping for the cable. coupler, and vehicle inlet, resulting in enhanced electromagnetic compatibility. In this paper, characteristics of the topology are derived and analyzed using two methods. Firstly, the fundamental mode ac sine-wave approximation is extended to battery loads and provides a simple, yet insightful, analysis of the topology. A second method of analysis is based on the more accurate, but complex, time-based modal approach. Finally, typical experimental results verify the analysis of the topology presented in the paper.

Hayes, J.G.; Egan, M.G.; Murphy, J.M.D.; Schulz, S.E.; Hall, J.T.

1999-08-01

314

Microenergy Converter Using Insect Wings  

Microsoft Academic Search

This paper is concerned with the development of novel type of micro wind energy converter using insect wings. A series of\\u000a experimental studies are made on the function of wing apparatus of flying insects. In the first place, the structural properties\\u000a of insect wings are studied through measurements of certain morphological parameters. The scanning electron microscopic observation\\u000a of an insect

Seiichi Sudo; Kazumasa Nashimoto; Koji Tsuyuki; Tetsuya Yano; Muneo Futamura

315

Human Lung Angiotensin Converting Enzyme  

PubMed Central

To enable its immunohistologic localization, angiotensin converting enzyme (EC 3.4.15.1) from human lung was solubilized by trypsinization and purified ?2,660-fold to apparent homogeneity from a washed lung particulate fraction. The specific activity of pure enzyme was estimated to be 117 ?mol/min per mg protein with the substrate hippuryl-l-histidyl-l-leucine. Consistent with previously described lung enzyme studies, catalytic activity was strongly inhibited by EDTA, O-phenanthroline, SQ 20,881, and SQ 14,225 and increased by CoCl2. SQ 20,881 was a somewhat more potent inhibitor than SQ 14,225, unlike rabbit lung enzyme. The Michaelis constant (Km) with hippuryl-l-histidyl-l-leucine was 1.6 mM. The molecular weight was estimated at 150,000 from sucrose density gradient centrifugation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a single polypeptide chain estimated at 130,000 daltons. Rabbit antibody to human lung enzyme was prepared by parenteral administration of pure angiotensin-converting enzyme in Freund's adjuvant. Rabbit antibody to human lung angiotensin-converting enzyme appeared to crossreact weakly with the rabbit enzyme and strongly inhibited the catalytic activity of the enzymes from human serum, lung, and lymph node. The specificity of the rabbit antibody and purity of the final human lung enzyme preparation was suggested by the single precipitin lines obtained by radial double immunodiffusion, and by the coincidence of enzyme catalytic activity and immunoreactivity on polyacrylamide gel electrophoresis, with both relatively pure and highly impure enzymes. Generally applicable sensitive analysis of acrylamide gels for immunoreactivity (and subsequently for any other activity) by use of intact gel slices in radial double immunodiffusion was devised. Human lung enzyme was very tightly bound to and catalytically active on anti-human enzyme antibody covalently bound to Sepharose 4B, and could not be readily dissociated without inactivation. Antibody to human lung angiotensin converting enzyme has permitted tissue localization of the enzyme, which appears to be clinically useful in diseases associated with abnormal abundance of angiotensin-converting enzyme in tissues, such as sarcoidosis. Images

Friedland, Joan; Silverstein, Emanuel; Drooker, Martin; Setton, Charlotte

1981-01-01

316

Direct Conversion Analog to Digital Converter.  

National Technical Information Service (NTIS)

A four bit subtractor analog to digital converter provides direct conversion of analog voltage signals into binary or binary coded decimal output signals for digital display or digital signal processing. The analog to digital converter utilizes a pluralit...

W. E. Chapple

1980-01-01

317

Frequency Converter, 60 Cps to 400 Cps.  

National Technical Information Service (NTIS)

The specification covers the requirements for a shipboard motor alternator, 60 cps to 400 cps frequency converter. The specifications define the frequency converter physical configuration and performance characteristics. (Author)

H. Clark

1965-01-01

318

Novel zero-voltage-transition PWM converters  

Microsoft Academic Search

A class of zero voltage transition (ZVT) power converters is proposed in which both the transistor and the rectifier operate with zero voltage switching and are subjected to minimum voltage and current stresses. The boost ZVT-PWM converter is used as an example to illustrate the operation of these converters. A 300 kHz, 600 W ZVT-PWM boost, DC-DC converter, and a

Guichao Hua; Ching-Shan Leu; Fred C. Lee

1992-01-01

319

Novel DC-DC Multilevel Boost Converter  

Microsoft Academic Search

This paper proposes a new DC-DC converter. The DC-DC multilevel boost converter, based on one inductor, one switch, 2N-1 diodes and 2N-1 capacitor, for N levels plus the reference (total N+1 levels), is a boost converter able to control and maintain the same voltage in all the Nx output levels, and able to control the input current. This converter is

Julio C. Rosas-Caro; Juan M. Ramírez; Pedro Martín García-Vite

2008-01-01

320

Auxiliary resonant DC tank converter  

DOEpatents

An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

Peng, Fang Z. (Knoxville, TN)

2000-01-01

321

Heat flow in a pyroelectric converter  

Microsoft Academic Search

A simulated pyroelectric converter has been constructed. The heat flow and temperature profiles within the converter have been measured. Computer simulations of the heat flow compare well with the measurements and predict an efficiency of 12 percent of the Carnot limit for a real pyroelectric converter with the operating configuration of the simulation. These heat flow results are useful in

R. B. Olsen; W. F. Butler; J. E. Drummond; D. A. Bruno; J. M. Briscoe

1985-01-01

322

Convertible undeniable signature with subliminal channels  

Microsoft Academic Search

The concept of subliminal channel was first proposed in 1983. After that, many subliminal channel schemes based on digital signatures are proposed. A convertible undeniable signature is an undeniable signature and can be converted to a general digital signature. In this paper, we combine both concepts to propose a new scheme which can embed subliminal channels into a convertible undeniable

Narn-yih Lee; Pei-hsiu Ho

2004-01-01

323

THERMIONIC CONVERTERS, NUCLEAR HEAT, AND POWER GENERATION  

Microsoft Academic Search

A thermionic converter is a static high-temperature engine convertirg ; heat to electricity. It is a vacuum- or gas-filled device containing a hot ; cathode and a cold anode. Properties and operating characteristics of typical ; types of converters are described. Nuclear energy such as produced in a power ; reactor is an ideal heat source for a thermionic converter.

Grattidge

1960-01-01

324

Analytic Signal Converter for Nondestructive Testing.  

National Technical Information Service (NTIS)

An analytic signal converter was developed to improve flaw detection in parts. The converter can resolve echoes 700 ns apart. The converter oprerates in real-time by using a single-sideband conversion technique, Weaver's Method. The transducer range is 1 ...

M. G. Duncan

1986-01-01

325

A microprocessor controlled piezoelectric power converter  

Microsoft Academic Search

Piezoelectric transformer (PT) for power conversion is receiving more and more attention because of its small thickness and high energy density. A major challenge of PT converter is the resonant characteristic of the PT that affects the performance of the whole converter. This paper presents a microprocessor controlled piezoelectric power converter system for cold cathode fluorescent lamp (CCFL) that can

S. W. Fung; M. H. Pong

2004-01-01

326

Effect of dietary monensin inclusion on performance, nutrient utilisation, rumen volatile fatty acid concentration and blood status of West African dwarf bucks fed with basal diets of forages.  

PubMed

This experiment investigated the effect of dietary monensin on performance, nutrient utilisation, rumen volatile fatty acid and blood status in West African dwarf (WAD) goats fed with basal diets of forages. Four concentrate supplements were formulated to include 0 (MO), 15 (M15), 30 (M30) and 45 (M45) mg monensin/kg dry matter. Twenty-four WAD bucks (7.3 ± 1.20 kg initial body weight, aged 9-12 months) were randomly allotted to four experimental diets in a completely randomised design for 90 days, six animals per diet. Results indicated that animals fed M15, M30 and M45 diets had lower (P < 0.01) dry matter and water intake than those fed M0 diet. Crude protein and neutral detergent fibre intakes by the bucks followed similar trend. Animals on M15, M30 and M45 had better (P < 0.001) feed and protein efficiency ratio than those fed M0 diet. Rumen pH and total volatile fatty acid concentration were maintained (P > 0.05) while monensin decreased (P < 0.001) acetate/propionate ratio. Blood glucose increased (P < 0.001) from 59.1 mg/dl in animals on M0 diet to 67.8, 66.0 and 66.3 mg/dl in animals on M15, M30 and M45 diets. Overall, there were no variations among animals on M15, M30 and M45 diets. It is concluded that feeding monensin at 15 to 45 mg/kg DM of supplemental concentrate diets to West African dwarf bucks could be effective in improving feed and protein efficiency, manipulating the rumen for increased propionate production and increasing blood glucose levels. PMID:22201011

Aderinboye, Ronke Yemisi; Onwuka, Chryss Friday Ijeoma; Arigbede, Oluwasanmi Moses; Oduguwa, Oluseyi Olutosin; Aina, Ayobami Bukola Joseph

2011-12-27

327

Changes in testicular development, ultrasonographic and histological appearance of the testis in buck kids immunized against LHRH using recombinant LHRH fusion protein.  

PubMed

This study was designed to evaluate the effectiveness of recombinant Ovalbumin-LHRL (OL) immunization on changes in testicular size, histological appearance and testosterone production in buck kids. Thirty native buck kids at 18 weeks of age were divided into three groups, control (n = 10), immunization (n = 10) and castration (n = 10) groups. Immunized animals received OL protein generated by recombinant DNA technology. Ultrasonographic and histological examinations of the testes were performed. Animals were slaughtered at 44 weeks of age. Semen and epididymides were evaluated for the presence of sperm cells. Immunized animals generated anti-LHRH antibodies. Testosterone production, testicular and accessory glands development and sperm production were suppressed in the immunized animals (p < 0.01). Semineferous tubule diameters decreased (p < 0.01), basal membrane of the tubule was thickened and hyalinized in immunized kids. Immunization affected ultrasonographic appearance of the testes drastically. While testes of control animals gained their normal ultrasonographic appearance as the age increased, immunized animals had uniform hypoechogenic testicular structure as observed at 18 weeks of age until slaughter. Simultaneous histological and ultrasonographic evaluations indicated that the changes in testicular histology could partly be monitored via ultrasonographic imaging; nevertheless, it is difficult to claim that ultrasonographic image reflects the exact changes in such instances. In conclusion, these results indicate that recombinant OL fusion protein is effective in immunocastration in buck kids and has a potential to be used as an alternative to physical castration. Further researches should be conducted to help assessing reproductive status of testes from ultrasound images. PMID:18507800

Ulker, H; Küçük, M; Yilmaz, A; Yörük, M; Arslan, L; deAvila, D M; Reeves, J J

2008-05-27

328

Fertility results after vaginal deposition of frozen-thawed buck semen diluted with two different extenders using one- or two-step procedures.  

PubMed

In two field trials (T1 and T2), the effect of two different extenders for buck semen was tested. Semen from six (T1) and seven (T2) bucks of the Norwegian Dairy Goat breed was diluted either in a milk-based extender containing egg yolk (M) or in a commercially available extender without egg yolk [Andromed(®) (A)]. Dilution in M was performed in a two-step procedure including centrifugation of the ejaculates and removal of the supernatant, while dilution in A was performed in one step. During the two trials (T1 and T2) 514 and 714, does, respectively, were artificially inseminated during natural oestrus, and the farmers performed the inseminations themselves after attending an artificial insemination (AI) training course. Vaginal insemination with 200 × 10(6) spermatozoa diluted in M resulted in a 25-day non-return rate (NRR) and kidding rate of 37.3% and 24.5%, respectively, while semen diluted in A resulted in 31.7% NRR and a kidding rate of 19.8% (T1). In T2, NRR and kidding rate for AI performed with semen diluted with M were 42.7% and 28.5%, respectively, while dilution in A gave 37.2% NRR and a kidding rate of 26.8%. There was no significant effect of extender in the two trials [T1:p=0.068 (NRR), p=0.148 (kidding rate), T2:p=0.096 (NRR), p=0.38 (kidding rate)], but farmer had a significant effect on the fertility parameters in both trials. In conclusion, the present studies may indicate that Andromed(®) is suitable for buck semen. However, more research is necessary to confirm the results and to improve the fertility of does after vaginal AI with frozen-thawed semen. PMID:20210882

Nordstoga, A B; Söderquist, L; Adnøy, T; Paulenz, H

2011-02-01

329

Bremsstrahlung converters for powerful industrial electron accelerators  

NASA Astrophysics Data System (ADS)

The converters were designed for generation of intensive bremsstrahlung radiation. The powerful electron beam (5MeV, 50kW) was generated by ILU-10 accelerator. The converters differ in technology of manufacturing and material of target, tungsten carbide or tantalum. The aluminum board with the channels for cooling water is used as the base of the converter and filter for low energy part of bremsstrahlung spectrum. The converters can be installed in vacuum or outside the accelerator in air under the beam window. The results of testing of different converters are given.

Auslender, V. L.; Bukin, A. D.; Voronin, L. A.; Kokin, E. N.; Korobeinikov, M. V.; Krainov, G. S.; Lukin, A. N.; Radchenko, V. M.; Sidorov, A. V.; Tkachenko, V. O.

2004-09-01

330

Synthesis of switched-mode converters  

NASA Astrophysics Data System (ADS)

An analytical synthesis method is described which is capable of generating the complete set of switching converters which possess given attributes. This leads to a number of useful new converter topologies, as well as to a more fundamental understanding of switched-mode conversion. Two examples are considered. It is found that the class of single-inductor two-topology converters contains seven basic members. In addition, a class of converters with nonpulsating input and output currents also contains seven members. Zero input or output current ripple may be obtained in three of these converters.

Erickson, R. W.

331

Radicalization of Homegrown Sunni Militants in the United States: Comparing Converts and Non-Converts  

Microsoft Academic Search

Are the mechanisms and processes that lead to radicalization different for Muslim converts and non-converts in the United States? While many scholars attempt to explain why people violently radicalize, the theories are diverse and most treat converts and non-converts the same. This study answers this question by categorizing the many radicalization theories into three levels of analysis so that cases

Scott Matthew Kleinmann

2012-01-01

332

High Power Density DC/DC Converter: Selection of Converter Topology.  

National Technical Information Service (NTIS)

The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; a...

D. M. Divan

1990-01-01

333

Thermionic converter emitter support arrangement  

DOEpatents

A support is provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

Allen, Daniel T. (La Jolla, CA)

1990-01-01

334

Thermionic converter emitter support arrangement  

DOEpatents

A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

Allen, Daniel T. (La Jolla, CA)

1990-01-01

335

Catalytic converter for an automobile  

SciTech Connect

A catalytic converter is described for an automobile comprising a single strip of metal folded back and forth upon itself, the strip having at least one slot along each line of folding, the slots being aligned with each other across adjacent layers of the strip, each folded slot defining a notch. The notches together define at least one groove along the periphery of the folded strip, and at least one canister section, the canister section being shaped to coincide with the shape of the folded strip, the canister section having at least one ridge shaped to mate with the groove, the canister section being wrapped around the folded strip so as to maintain the strip in a fixed position.

Retallick, W.B.

1986-03-18

336

Heat flow in a pyroelectric converter  

NASA Astrophysics Data System (ADS)

A simulated pyroelectric converter has been constructed. The heat flow and temperature profiles within the converter have been measured. Computer simulations of the heat flow compare well with the measurements and predict an efficiency of 12 percent of the Carnot limit for a real pyroelectric converter with the operating configuration of the simulation. These heat flow results are useful in considerations of heat engines using active materials other than pyroelectrics, such as Nitinol, when these engines utilize similar heat flow management.

Olsen, R. B.; Butler, W. F.; Drummond, J. E.; Bruno, D. A.; Briscoe, J. M.

1985-12-01

337

Gadolinium sheet converter for neutron radiography.  

PubMed

This work describes a methodology developed for the confection of gadolinium sheet converter for neutron radiography using the gadolinium chloride (GdCl3) as material converter. Though manufactured at a relatively low cost, they are as good as the sheet converter on the market. Here, we present neutron radiography of the penetrameter, the edge spread function, the modulation transfer function and characteristic curves for each set sheet-AA400 Kodak film. PMID:17702586

Lima, C T S; Crispim, V R; Santos, W M S

2007-07-17

338

Converted-wave seismology for coal exploration  

Microsoft Academic Search

Despite the success of multi-component seismology and asso- ciated converted-wave (PS-wave) imaging methods in the petroleum industry, there has been relatively little effort devoted to shallow, high-resolution converted-wave imaging in the coal sector. By analogy to petroleum-scale applications, converted-wave seismic imaging in the coal environment offers interesting possibilities for independent validation of mapped stru c t u res, clearer imaging

Natasha Hendrick

339

New passive polarization converter on glass substrate  

Microsoft Academic Search

We report on a new design and realization of highly efficient passive polarization converters made by K+-Na+ ion-exchange on glass substrate. The converter principle is based on periodic application of integrated asymmetric ion-exchanged stress segments. Polarization conversion up to 99% at low excess losses of less than 0.4 dB has been achieved. The converters combine the advantages of a highly

Thiemo Lang; F. Bahnmuller; P. Benech

1998-01-01

340

Fault-Tolerant Multilevel Converter Topology  

Microsoft Academic Search

This paper presents a modified topology of the neutral-point-clamped converter. The main change consists on adding a fourth leg, which is based on the flying-capacitor converter structure. The aim of this additional leg is to provide fault tolerance to the converter. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage

Salvador Ceballos; Josep Pou; Igor Gabiola; J. L. Villate; Jordi Zaragoza; Dushan Boroyevich

2006-01-01

341

Low-frequency characterization of PWM converters  

NASA Astrophysics Data System (ADS)

Low-frequency components of states or outputs in PWM dc and ac converters can be characterized by differential equations called describing equations. These equations are derived by inspection of converter topology and use of switching functions and duty ratios. Their steady-state and small-signal dynamic solution shows how energy-storage elements in a converter/load system shape the frequency response of conversion functions established by the switches.

Ngo, K. D. T.

342

One-cycle control of switching converters  

Microsoft Academic Search

A pulsed nonlinear control technique, one-cycle control, is introduced. This technique takes advantage of the pulsed and nonlinear nature of switching converters and achieves instantaneous control of the average value of the chopped voltage or current. This technique provides fast dynamic response and good input-perturbation rejection. It is suitable for the control of pulsewidth-modulated (PWM) converters and quasi-resonant converters. The

Keyue M. Smedley; Slobodan Cuk

1991-01-01

343

National Dam Inspection Program. Newtown Dam (NDS I.D. Number PA 01604, DER I.D. Number 9-178, SCS PA 621), Delaware River Basin, Newtown Creek, Bucks County, Pennsylvania. Phase I Inspection Report.  

National Technical Information Service (NTIS)

Newtown Dam is owned by the Neshaminy Water Resources Authority and maintained by Bucks County. The dam and reservoir are used as a flood control structure for the downstream town of Newtown, Pennsylvania. The impoundment was designed by the United States...

M. F. Buck J. H. Frederick

1980-01-01

344

CMOS pH-to-Digital Converter  

Microsoft Academic Search

A CMOS delta-sigma (??) pH-to-digital converter has been developed for continuous monitoring of H+-ion concentrations. The SnO2\\/ITO glass, fabricated sputtering SnO2 on the conductive ITO glass, was used as a pH-sensitive membrane of extended gate field effect transistor (EGFET) operational amplifier. The ?? pH-to-digital converter, constructed by using EGFET-OP to realize switched-capacitor (SC) ?? converter, converted the H+-ion concentration into

Chung-Yuan Chen; Tai-Ping Sun; Hsiu-Li Hsieh

2010-01-01

345

Public Health Advisory: Angiotensin-Converting Enzyme ...  

Center for Drug Evaluation (CDER)

... Public Health Advisory: Angiotensin-Converting Enzyme Inhibitor (ACE inhibitor) Drugs and Pregnancy. [ACE inhibitor drugs ... More results from www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandproviders

346

Generation and classification of PWM dc-to-dc converters  

NASA Astrophysics Data System (ADS)

A method is presented by which generation and classification of pulsewidth-modulated (PWM) dc-to-dc converters can be effected. Fundamental blocks known as converter cells can be used to generate a plethora of converters leading to a number of useful new converter topologies. A classification of basic converters is proposed in terms of converter-cell generated families.

Tymerski, Richard; Vorperian, Vatche

1988-11-01

347

Multilevel converters for 10 MW Wind Turbines  

Microsoft Academic Search

Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters, therefore the evaluations are mainly focused on the power device thermal performances, which are closely related to the life

Ke Ma; Frede Blaabjerg

2011-01-01

348

Machine and Converter Reliabilities in Wind Turbines  

Microsoft Academic Search

Electrical Machine\\/Converter combinations are used in a variety of applications, from powers of Watts to MegaWatts. Some applications, such as propulsion and generation, have high reliability & availability requirements. Modern large wind turbines incorporate variable pitch blades and a variable speed Generator, which feeds the Grid through a Converter and have a need for high reliability & availability. There are

P J Tavner; G J W van Bussel; F Spinato

349

Thermionic converters for ground demonstration testing  

NASA Astrophysics Data System (ADS)

Sixteen thermionic converters were fabricated for the Engine Ground Demonstration (EGD) tests of the Integrated Solar Upper Stage (ISUS). EGD power generation tests mapped the array performance under simulated semi-synchronous orbit conditions. Results from these tests have been reported elsewhere. This paper describes converter development and the manufacturing techniques used to ensure good performance, reliability and minimum unit-to-unit variations.

Talbot, Gregory J.; Ramsey, William D.; James, Edmund L.

1998-01-01

350

Converter concepts to increase the integration level  

Microsoft Academic Search

In the previous work, a way to improve packaging of power electronic converters by increasing integration level and using multifunctional construction parts is presented. The quantities intended to evaluate integration level and volumetric utilization in power converters are introduced. Based on these values, a number of methods to increase the integration level are presented. A design process in the form

Jelena Popovic; J. A. Ferreira

2005-01-01

351

Cooperative converters in power electronic systems  

Microsoft Academic Search

The specifications of power electronic systems are becoming ever more exigent - better performance (dynamic and steady state), increased efficiency, reliability, and quality, and decreased power rating, size (volume and weight), and cost. One strategy for the overall improvement of these systems is to use various cooperating converters with the system functions being shared among them, optimizing each converter for

E. Romero-Cadaval; M. I. Milane?s-Montero

2010-01-01

352

Series resonant converter using flyback control  

Microsoft Academic Search

Series resonant converters are widely used in applications requiring high power density. They offer several advantages over other topologies such as simplicity of design, switching at zero current levels, and high efficiency due to low switching losses. A new converter will be proposed that delivers pulses of equal energy to the load with comparatively small pulse-to-pulse delay and draws sinusoidal

H. T. Lee; L. C. Josephs

1985-01-01

353

RF digital-to-analog converter  

DOEpatents

A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

Conway, P.H.; Yu, D.U.L.

1995-02-28

354

RF digital-to-analog converter  

DOEpatents

A digital-to analogue converter for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration.

Conway, Patrick H. (Rancho Palos Verdes, CA); Yu, David U. L. (Rancho Palos Verdes, CA)

1995-01-01

355

ZETA converter applied in power factor correction  

Microsoft Academic Search

This paper presents the analysis of the ZETA converter operating in discontinuous conduction mode (DCM) for power factor correction. The main attraction of the ZETA converter is that it is a naturally isolated structure, which allows a regulated output voltage with only one power processing stage. The principle of operation, mathematical analysis, design procedure and experimental results obtained from a

ADRIANO PERES; DENIZAR CRUZ MARTINS; I. Barbi

1994-01-01

356

Intentional islanded operation of converter fed microgrids  

Microsoft Academic Search

This paper develops a dynamic model of a converter fed islanded microgrid and proposes a control scheme to regulate its voltage and frequency. The model, which is formulated in an instantaneously synchronized reference frame, shows that the microgrid voltage depends on the real power balance between the converter and the load while reactive power balance determines the frequency. These results

Charles K. Sao; Peter W. Lehn

2006-01-01

357

Dammann-grating-based optodigital position converter  

NASA Astrophysics Data System (ADS)

An optodigital position converter based on a Dammann grating is proposed. The converter is based on a diffraction grating with a high diffraction efficiency coupled with a binary encoding mask. The module permits parallel processing of a scene so that one can extract the position of a correlation peak. Compression of the information is also performed. The binary output is compatible with digital systems.

Bergeron, Alain; Gingras, Denis; Arsenault, Henri H.

1995-09-01

358

DC current sensor for PWM converters  

Microsoft Academic Search

A sensor for inductor current in PWM converters which offers improved performance over presently available sensors is presented. The sensor is based on a saturable transformer, derives power from existing converter waveforms, provides DC isolation, and has inherently wide bandwidth. The sensor is compared to available current sensors. A theory of operation for the sensor is presented, the results of

Arthur W. Kelley; John E. Titus

1991-01-01

359

Distributed electrical leads for thermionic converter  

DOEpatents

In a thermionic converter, means are provided for coupling an electrical lead to at least one of the electrodes thereof. The means include a bus bar and a plurality of distributed leads coupled to the bus bar each of which penetrates through one electrode and are then coupled to the other electrode of the converter in spaced apart relation.

Fitzpatrick, Gary O. (Livermore, CA); Britt, Edward J. (Cupertino, CA)

1979-01-01

360

Application of integrated magnetics in resonant converters  

Microsoft Academic Search

The physical size of inductors in resonant converters was examined in terms of inductor to transformer size ratio. Following the general discussion of the issue, the inductor size in a series resonant DC-DC converter is examined in detail. It is shown that the inductor to transformer size ratio is a function of the peak voltage of the inductor to the

Arkadiy Kats; Gregory Ivensky; Sam Ben-Yaakov

1997-01-01

361

The detoxication of nitrate by two antioxidants or a probiotic, and the effects on blood and seminal plasma profiles and reproductive function of New Zealand White rabbit bucks.  

PubMed

Forty-two New Zealand White male rabbits were housed individually in wire cages and randomly distributed among six experimental groups of seven rabbits each, during 16 to 61 weeks of age. There were three main nitrate groups: 0 (tap water), 350 and 700 ppm. Within the 700 ppm of nitrate, there were four subgroups, in which one group was used as control group and the other three groups were supplemented with either 200 ppm of ascorbic acid (vitamin (Vit) C), 200 ppm of Vit E with 0.2 ppm of selenium (Se) and 1000 ppm of probiotic. The nitrate was supplemented as a sodium nitrate. The aim is to test the ability of Vit C and Vit E, Se and probiotic on the deleterious effects (blood and seminal plasma biochemical constituents, semen quality and productive performance) of nitrate in drinking water. Rabbits given nitrate at 700 ppm had significantly lower plasma globulin, red blood cells (RBCs), hemoglobin (Hgb), packed cell volume % (PCV%) and total antioxidant capacity (TAC) than those given the other concentrations of nitrate. Vit C, Vit E with Se and probiotic resulted in significantly (P < 0.05) greater Hgb, RBCs, PCV% and TAC than those of bucks given water supplemented with only 700 ppm nitrate, but the aspartate aminotransferase and alanine aminotransferase concentrations in seminal plasma were lower. Testosterone in the blood plasma and the seminal plasma was significantly (P < 0.05) lower in rabbits given 700 ppm nitrate than in those given other concentrations of nitrate. Vit C, Vit E with Se and the probiotic significantly increased testosterone, fertility, number of offspring and total offspring weight of rabbits sired by bucks supplemented with 700 ppm of nitrate. PMID:23177268

Attia, Y A; Abd El Hamid, E A; Ismaiel, A M; El-Nagar, A

2012-11-26

362

Multimodule parallel series-loaded resonant converters  

NASA Astrophysics Data System (ADS)

The design and implementation of a multimodule parallel series-loaded resonant (SLR) converter system is presented. The SLR converter to be paralleled is operated in the n = 2 discontinuous mode (DCM). Its dc analysis and dynamic modeling are made. In parallel operation, an average control technique is proposed to compensate the mismatch in current control characteristics of each parallel converter. Good dynamic and static current sharing characteristics are obtained. In addition, to obtain good output voltage regulating control performance, a design procedure is presented to find the parameters of feedback voltage controller according to the prescribed specifications.

Chiang, S. J.; Liaw, C. M.; Ouyang, J. H.; Chiang, C. C.

1995-01-01

363

Three-Phase Constant-Current Source Using Immittance Converter  

Microsoft Academic Search

The immittance converter is the combined word for the impedance-admittance converter. The immittance converter has an input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant voltage source

Hisaichi Irie; Shunsuke Oohashi

2004-01-01

364

Multichannel Measuring Converter for Temperature Control.  

National Technical Information Service (NTIS)

Described is the multichannel measuring normalizing converter constructed on the base of magnetic second harmonic modulators and intended for preliminary voltage amplification of thermocouples controlling the unit discharge chamber temperature. The conver...

M. P. Vasil'ev V. G. Ivkin Y. M. Fedorishin

1979-01-01

365

Light-off behavior of catalytic converters  

SciTech Connect

This paper studies a system of partial differential equations modeling the behavior of an automotive catalytic converter. The particular phenomenon considered in detail is light-off, when the temperature of the converter changes dramatically from cold to hot somewhere within the converter. The initial position of light-off and the subsequent movement of this steep jump in temperature toward the inlet of the converter are analyzed. The method of matched asymptotic expansions is used to study light-off and to derive approximate formulas that determine its behavior in the limits of small heat diffusion and large activation energy. Numerical calculations are presented and are used to compare with the analytical formulas. These calculations reveal that the asymptotic results for small diffusion are quantitatively accurate, while those for small diffusion and large activation energy give the qualitative behavior of the solution but give poor quantitative predictions for the range of parameters encountered in practice.

Please, C.P.; Hagan, P.S.; Schwendeman, D.W.

1994-02-01

366

Optimization of Aperiodic Waveguide Mode Converters.  

National Technical Information Service (NTIS)

Previous studies by Haq, Webb and others have demonstrated the design of aperiodic waveguide structures to act as filters and mode converters. These aperiodic structures have been shown to yield high efficiency mode conversion or filtering in lengths cons...

G. J. Burke D. A. White C. A. Thompson

2004-01-01

367

Power system applications for PASC converter systems.  

National Technical Information Service (NTIS)

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source level voltage converter system. The method can be applied to any single terminal pair source w...

M. K. Donnelly R. M. Johnson

1994-01-01

368

New magnetic structures for switching converters  

NASA Astrophysics Data System (ADS)

It is pointed out that heretofore the majority of processing applications have centered on very few standard switching converter topologies. Recently, a number of new converter topologies have been proposed in the hope of finding the best possible electrical interconnection of power processing elements (switches, storage components, and transformers) with respect to efficiency and performance. The complementary problem, of equal importance, regarding the magnetic interconnection, however, has been completely overlooked. In certain of the new converter structures, the nature of the switching process and existing waveforms has made the integration of previously separate inductors and transformers into a single magnetic structure possible. Several magnetic core structures of this type are proposed and analyzed here. These are seen as leading to further converter simplifications and performance improvements.

Cuk, S.

1983-03-01

369

Angiotensin-Converting Enzyme Inhibitor (ACE inhibitor) ...  

Center for Drug Evaluation (CDER)

... events associated with the use of these ... FDA MedWatch program using the contact ... Professionals: Angiotensin-Converting Enzyme Inhibitor (ACE ... More results from www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandproviders

370

Damping assembly for a torque converter clutch  

SciTech Connect

This patent describes a turbine damped torque converter and clutch. It comprises: a pressure plate; a torque converter turbine; a torque converter impeller; means including a control chamber for the pressure plate means for controlling the apply and release of the clutch for engaging the clutch with the impeller; a torque converter output shaft; a planetary gear arrangement including an input gear drivingly connected with the pressure plate, a reaction gear drivingly connected with the turbine, an output member drivingly connected with the output shaft and pinion gear means meshing with the input gear and the reaction gear for drivingly interconnecting the turbine and the pressure plate at a drive ratio of the turbine to the pressure plate of less than 1:1; and one-way drive means disposed between the turbine and the output shaft for preventing the turbine from overrunning the output shaft.

Dull, D.C.

1989-12-26

371

Analog-to-digital converter technology comparison  

Microsoft Academic Search

Analog-to-digital converters are ubiquitous, critical components of signal processing systems. This presentation surveys the state-of-the-art for ADCs and includes both experimental converters and commercially available parts. The shape of the distribution on a resolution vs. sampling rate graph provides insight into ADC performance limitations. For sampling frequencies ranging from ?0.5 MSPS to ?4 GSPS, resolution falls off by ?1 bit

R. H. Walden

1994-01-01

372

Performance trends for analog to digital converters  

Microsoft Academic Search

Analog-to-digital converters are key components of signal processing systems, and may even dictate system architectures due to their limitations on sampling rate and resolution. The state of the art for ADCs, including both experimental converters and commercially available parts, is reviewed. The data imply that the performance measure, P=2SNRbits·fsamp, uncertainty in the sampling process (aperture jitter) over a very wide

Robert H. Walden

1999-01-01

373

Multifrequency averaging of DC\\/DC converters  

Microsoft Academic Search

This paper presents some of the issues involved in applying frequency-selective averaging to modeling the dynamic behavior of pulsewidth-modulated (PWM) DC-DC converters. We use the boost converter as an example to show the details involved in deriving some novel extended averaged models, and we use simulations to highlight the accuracy of the models even when traditional small-ripple conditions are not

V. A. Caliskan; O. C. Verghese; A. M. Stankovic

1999-01-01

374

Method of processing converted mode seismic data  

SciTech Connect

This patent describes method for processing converted mode seismic data. Compressional and converted compressional to shear wave data is acquired by generating compressional energy into a subsurface formation and recording the amplitude of reflections as a function of time at spaced locations along a line of exploration. A series of compressional to shear wave velocity (Vp/Vs) ratios are selected based on an analysis of the acquired seismic data. The shear wave velocity for each Vp/Vs ratio is determined.

Bloomquist, M.G.; Warner, B.N.

1989-11-14

375

ANALOG-TO-DIGITAL DATA CONVERTER  

DOEpatents

Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.

1960-09-01

376

General analysis of harmonic transfer through converters  

Microsoft Academic Search

Harmonic transfer from DC-side to AC-side and vice-versa through a three-phase bridge power converter is treated by using space vectors. The dependency of the relative frequency of a harmonic and its sequence (positive\\/negative) is illustrated. It is shown that the derived relationships are valid for both voltage-source and current-source power converters. Thereby, the relationships for the frequency transformation through power

Ying Jiang; A. Ekstrom

1997-01-01

377

Novel zero-voltage-transition PWM converters  

Microsoft Academic Search

To date, soft-switching techniques applied to the PWM converters, with the exception of a few isolated cases, are subjected to either high switch voltage stresses or high switch current stresses, or both. A new class of zero-voltage-transition PWM converters is proposed, where both the transistor and the rectifier operate with zero-voltage switching and are subjected to minimum voltage and current

Guichao Hua; Ching-Shan Leu; Yimin Jiang; Fred C. Y. Lee

1994-01-01

378

Application of microcontrollers to control HVDC converters  

Microsoft Academic Search

The author presents the design of the hardware and software of the AC\\/DC converter controllers for an HVDC transmission system. The structure of the converter controllers is based on a 16-b microcontroller. The microcontroller includes the facilities needed to support fast real-time control in a single chip. The main functions included in the terminal controllers are the control of the

Edmundo Barrera-Cardiel

1993-01-01

379

An oversampling converter for strain gauge transducers  

Microsoft Academic Search

An oversampling converter that directly digitizes low-level strain gauge transducer outputs is presented. An instrumentation amplifier and two independent chopper-stabilized delta-sigma modulators amplify and convert the transducer's output and excitation. Digital division of the two independent conversions produces a 20-b ratiometric measurement. Drift due to external thermocouple junctions and RF rectification is eliminated by AC excitation of the transducer. Interference

Donald A. Kerth; Douglas S. Piasecki

1992-01-01

380

TCO Endpoint Control System for Converter Steelmaking  

Microsoft Academic Search

\\u000a In the course of production technology of converter steelmaking, accurate and fast measurement such technical indicators as\\u000a temperature, content of carbon and content of oxygen of molten steel in the converter, especially the technical indicator\\u000a of the molten steel of endpoint, it is significant to guarantee the quality of steel products and reducing energy consumption.\\u000a The structure of equipments, the

Yanhua Zhao; Jianyi Kong; Jintang Yang; Zhaohui Xia; Gongfa Li

381

78 FR 40132 - Wave Energy Converter Prize Administration Webinar  

Federal Register 2010, 2011, 2012, 2013

...Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar...Announcement (FOA), tentatively titled, ``Wave Energy Converter Prize Administration...structuring a prize competition related to wave energy converters. The WWPTO...

2013-07-03

382

Control of Paralleled Negative Output Elementary Luo Converters  

Microsoft Academic Search

DC to DC converters are widely used in applications such as computer hardware peripherals, power supplies, car auxiliary power supplies, servo-motor drives and medical equipments. Luo converter is a recently developed DC-DC converter. Negative output Luo converter performs the conversion from positive source voltage to negative load voltage. Parallel connection of DC-DC converters is used when available converters are of

R. Kayalvizhi; S. P. Natarajan; P. Suresh Pandiarajan; R. Vijayarajeswaran

2005-01-01

383

Bidirectional forward-flyback DC-DC converter  

Microsoft Academic Search

Bi-directional DC-DC converter is widely used in more and more areas. The paper proposed a novel type of bi-directional DC-DC converter topologies-forward-flyback bi-directional DC-DC converters. The converter has the following merits: 1) The spike on the switches is much smaller than the current-fed type converter, the energy that cause the spike is much smaller than that in the current-fed converter;

Fanghua Zhang; Lan Xiao; Yangguang Yan

2004-01-01

384

Bidirectional converter interface for a battery energy storage test bench  

Microsoft Academic Search

This paper presents the bidirectional converter interface for a 6 kV battery energy storage test bench. The power electronic interface consists a two stage converter topology having a low voltage dc-ac grid connected converter and a new dual active bridge dc-dc converter with high transformation ratio. The dc-dc converter controls the battery charge\\/discharge current while the grid converter controls the

Ionut Trintis; Stephan Thomas; Tobias Blank; Christoph Roggendorf; Stig Munk-Nielsen; Remus Teodorescu

2011-01-01

385

Ac-dc converter firing error detection  

SciTech Connect

Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal.

Gould, O.L.

1996-07-15

386

The effect of raffinose and methionine on frozen/thawed Angora buck (Capra hircus ancryrensis) semen quality, lipid peroxidation and antioxidant enzyme activities.  

PubMed

The aim of the present study was to determine the effects of different doses of raffinose and methionine on post-thawed semen quality, lipid peroxidation and antioxidant enzyme activities of Angora buck (Capra hircus ancryrensis) sperm following cryopreservation. Ejaculates collected from three Angora bucks were evaluated and pooled at 37 degrees C. Semen samples, which were diluted with a Tris-based extender containing the additives raffinose (2.5, 5, 10mM) and methionine (2.5, 5, 10mM) and an extender containing no antioxidants (control), were cooled to 5 degrees C and frozen in 0.25 ml French straws. Frozen straws were thawed individually at 37 degrees C for 20s in a water bath for evaluation. The freezing extender supplemented with 2.5 and 5mM methionine led to higher percentages of CASA motility (63.6+/-7.0; 63.4+/-3.1%, respectively), in comparison to the controls (P<0.01) following the freeze-thawing process. The addition of antioxidants did not provide any significant effect on the percentages of post-thaw subjective and CASA progressive motilities as well as sperm motion characteristics (VSL and VCL), compared to the control groups (P>0.05). The freezing extender with raffinose (5 and 10mM) and methionine at three different doses (2.5, 5 and 10mM) led to lower percentages of acrosome abnormalities, in comparison to the controls (P<0.001). In the comet test, raffinose (5 and 10mM) and methionine (10mM) gave scores lower than those of the controls, and thereby reduced DNA damage (P<0.05). Malondialdehyde formation was found to be lower (1.8+/-0.1 nmol/L) in the group of 5mM raffinose, compared to the controls following the freeze-thawing process (P<0.01). The additives did not show any effectiveness on the maintenance of SOD, GSH-PX and GSH activities, when compared to the controls (P>0.05). In conclusion, methionine and raffinose play a cryoprotective role against sperm CASA motility, acrosome abnormality and DNA damage. Raffinose 5mM exhibited antioxidative properties, decreasing MDA levels. Further studies are required to obtain more concrete results on the characterization of microscopic parameters and antioxidant activities in cryopreserved goat sperm with different additives. PMID:20515679

Tuncer, Pürhan Barbaros; Bucak, Mustafa Numan; Sariözkan, Serpil; Sakin, Fatih; Yeni, Deniz; Ci?erci, Ibrahim Hakki; Ate??ahin, Ahmet; Avdatek, Fatih; Gündo?an, Mustafa; Büyükleblebici, Olga

2010-05-31

387

Power system applications for PASC converter systems  

SciTech Connect

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source level voltage converter system. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here employs banks of transformers, one bank per phase, in which the primaries are connected in parallel through a switch matrix to the dc source. Two opposite polarity primaries per transformer are pulsed alternatively in time to produce an oscillatory sinusoidal output waveform. PASC conversion system capabilities to produce both leading and lagging power factor power output in single-phase and three-phase {Delta} or Y configurations are illustrated. EMTP simulations are used to demonstrate the converter capabilities. Also included are discussions regarding harmonics and potential control strategies to adapt the converter to an application or to minimize harmonics.

Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Johnson, R.M. [Montana State Univ., Bozeman, MT (United States)

1994-04-01

388

Power system applications for PASC converter systems  

SciTech Connect

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source voltage converter systems. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here employs banks of transformers, one bank per phase, in which the primary are connected in parallel through a switch matrix to the dc source. Two opposite polarity primaries per transformer are pulsed alternatively in time to produce an oscillatory sinusoidal output waveform. PASC conversion system capabilities to produce both leading and lagging power factor power output in single-phase and three-phase {Delta} or Y configurations are illustrated. EHTP simulations are used to demonstrate the converter capabilities. Also included are discussions regarding harmonics and potential control strategies to adapt the converter to an application or to minimize harmonics.

Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Johnson, R.M. [Montana State Univ., Bozeman, MT (United States)

1995-01-01

389

Power system applications for PASC converter systems  

NASA Astrophysics Data System (ADS)

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source level voltage converter system. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here employs banks of transformers, one bank per phase, in which the primaries are connected in parallel through a switch matrix to the dc source. Two opposite polarity primaries per transformer are pulsed alternatively in time to produce an oscillatory sinusoidal output waveform. PASC conversion system capabilities to produce both leading and lagging power factor power output in single-phase and three-phase (Delta) or Y configurations are illustrated. EMTP simulations are used to demonstrate the converter capabilities. Also included are discussions regarding harmonics and potential control strategies to adapt the converter to an application or to minimize harmonics.

Donnelly, M. K.; Johnson, R. M.

1994-04-01

390

Kinetics : CatalyticConverters (4 Variations)  

NSDL National Science Digital Library

The following table illustrates the changes in emissions requirements for automobiles: Pollutant 1970 Emissions 1990 Emissions CA ultra-low emissions C x H y 1.5 g/mile 0.25 g/mile 0.04 g/mile CO 15 g/mile 3.4 g/mile 1.7 g/mile NO x 3.1 g/mile 0.4 g/mile 0.2 g/mile Catalytic converters are used in automobiles to convert pollutants in engine emissions to benign products. Catalytic converters in today's automobiles are made of a porous ceramic brick that has been coated with catalysts, additives, stabilizers, and support materials. Corning has developed bricks that have very thin-walled channels with 600 channels per square inch. Which of the following research goals did they target?

391

Metamaterial polarization converter analysis: limits of performance  

NASA Astrophysics Data System (ADS)

In this paper, we analyze the theoretical limits of a metamaterial-based converter with orthogonal linear eigenpolarizations that allow linear-to-elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50 %, while the realistic reflection configuration can give the conversion efficiency up to 90 %. We show that a double layer transmission converter and a single layer with a ground plane can have 100 % polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design for virtually any frequency range of the electromagnetic waves.

Markovich, Dmitry L.; Andryieuski, Andrei; Zalkovskij, Maksim; Malureanu, Radu; Lavrinenko, Andrei V.

2013-03-01

392

Design of high power density DC Bus Converter based on LLC resonant converter with synchronous rectifier  

Microsoft Academic Search

The LLC resonant converter can easily achieve soft-switching and magnetic components integration that makes it an excellent candidate for DC bus converter. In low voltage high output current applications, the design of synchronous rectifier (SR) and transformer is the key issue. A SR driving scheme with less circuit complexity is adopted for switching frequency at the resonant frequency in this

Niu Huapeng; Pei Yunqing; Yang Xu; Wang Laili; Wang Zhaoan

2009-01-01

393

High Current, Low Voltage Power Converter [20kA, 6V] - LHC Converter Prototype  

Microsoft Academic Search

The superconducting LHC accelerator requires high currents (approximately 12.5 kA) and relatively low voltages (approximately 10 V) for its magnets. The need to install the power converters underground is the driving force for reduced volume and high efficiency. Moreover, the LHC machine will require a very high level of performance from the power converters, particularly in terms of DC stability,

F. Bordry; A. Dupaquier; G. Fernqvist; H. E. Jorgensen; P. Madsen; E. Steinmann

1997-01-01

394

Global Hybrid Modeling and Control of DC-DC Converters: A Boost Converter Topology  

Microsoft Academic Search

Developing efficient and appropriate modeling and control techniques for DC-DC converters is of major importance in power electronics area and has attracted much attention from automatic control theory. Since DC-DC converters have a complex hybrid nature, recently several techniques based on hybrid modeling and control are introduced. These techniques have shown better results as compared to conventional averaging based schemes

Mohammad Hejri; Hossein Mokhtari

395

Quasi-resonant converters - Topologies and characteristics  

NASA Astrophysics Data System (ADS)

In designing switching dc-dc converters, the effort to increase operating frequency to reduce weight, size, and cost of magnetic and filter elements is constantly hampered by higher switching stresses and switching losses. To overcome these obstacles, the concept of the 'resonant switch' is proposed. By incorporating additional inductor and capacitor elements to shape the semiconductor switch's current waveform, a 'zero-current switching' property can be realized. Based on the resonant switch technique, a new host of quasi-resonant converter circuits have been derived, which can be operated in the megahertz range.

Liu, Kwang-Hwa; Oruganti, Ramesh; Lee, Fred C. Y.

1987-01-01

396

STUDY OF TIME-TO-PULSE-HEIGHT CONVERTER  

Microsoft Academic Search

The methods for time analysis are reviewed briefly, and a time-to-pulse-; height converter was developed based on the Rossi- alpha method. The ; specifications and circuit of the converter are described in detail. A device ; was developed for the simple calibration of the converter. The converter ; characteristics, which include linearity over the entire range, are described. ; (D.L.C.);

Y. Murata; E. Arai; E. Takeda

1962-01-01

397

Efficient HVDC converter model for real time transients simulation  

Microsoft Academic Search

An efficient model has been developed to simulate high voltage direct current (HVDC) power converters in real-time transient simulators. Real time performance of 45 ?s per solution step has been achieved for a 12-pulse monopolar converter and 81 ?s for the bipolar converter using a single processor Pentium Pro 200 MHz desktop computer. The HVDC power converter model is solved

S. Acevedo; L. R. Linares; J. R. Marti; Y. Fujimoto

1999-01-01

398

Electrostatic direct energy converter performance and cost scaling laws  

Microsoft Academic Search

Simplified equations were presented for each of the important loss mechanisms in both single stage direct converters and multistage venetian blind type direct converters. These equations can be used to estimate the efficiency and electric power output of the direct converter subsystem. Scaling relations for the cost of each major component in the direct converter subsystem were also given; these

M. A. Hoffman

1977-01-01

399

Quasi-electrostatic converters in materials' quality control  

Microsoft Academic Search

The action of electrostatic converters is based on well known in physics phenomenon of electrostatic induction. A construction of converters may be various depending on properties of materials (structures) under investigation and on control or measurement objectives. Schematic diagrams of vibrating probe converter and capacity converter with linear varying voltage pulse source are presented in the paper and the main

S. Sakalauskas; R. Pûras; Z. Vaitonis

400

Rotating-hoop, pulsed-energy converter  

NASA Astrophysics Data System (ADS)

The rotating-hoop, pulsed energy converter (ROHPEC) is a system that uses an integrated generator/flywheel to store terajoules (1 times 10 to the 12th power J) of energy and deliver gigawatts of power. The generator and all associated power conversion and conditioning hardware will be modifications to existing designs. The flywheel will use composite technology that has been subscale tested.

McKee, Bobby D.

401

Method of making a catalytic converter  

SciTech Connect

Arrangement for resiliently mounting a ceramic monolithic type catalytic converter element in a metal housing with a blanket of knit wire mesh material includes at least one circumferential band of high temperature intumescent material containing ceramic fibers positioned within the wire mesh blanket which prevents virtually all bypass leakage around the element and substantially reduces the temperature of the wire mesh.

Bailey, C.H.; De Palma, T.V.; Dillon, J.E.

1982-08-10

402

Machine for converting thermal energy into work  

Microsoft Academic Search

A closed circuit machine for converting thermal energy into work has a heating fluid circulating therethrough which constitutes a source of heat. The machine includes a tank adapted to hold liquid and traversed by a first coil for circulating the heating fluid. The coil has two ends which are attached to a basin containing liquid. A condenser is positioned above

Dachon

1982-01-01

403

Spectral converters and luminescent solar concentrators  

Microsoft Academic Search

In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of luminescent solar concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples

Petra F. Scudo; Luigi Abbondanza; Roberto Fusco; Luciano Caccianotti

2010-01-01

404

Molecular pharmacology of endothelin converting enzymes  

Microsoft Academic Search

A critical processing step in endothelin biosynthesis is the conversion of the intermediate “big endothelin” to its biologically active product catalysed by endothelin converting enzyme (ECE). In this commentary we discuss critically the cellular location, structure, and activity of the isoforms of ECE. The current evidence supporting a metallopeptidase ECE as the physiological regulator of endothelin production is described. Its

Anthony J. Turner; Leonard J. Murphy

1996-01-01

405

Converting Waste Plastic to Hydrocarbon Fuel Materials  

Microsoft Academic Search

The increased demand and high price for energy sources are driving efforts to convert organic compounds into useful hydrocarbon fuels. Although much of this work has focused on biomass, there are strong benefits to deriving fuels from waste plastic material. Waste plastic is abundant and its disposal creates large problems for the environment. Plastic does not break down in landfills,

Moinuddin Sarker

2011-01-01

406

Power electronics converters for wind turbine systems  

Microsoft Academic Search

The steady growth of installed wind power which reached 200 GW capacity in 2010, together with the up-scaling of the single wind turbine power capability - 7 MW's has been announced by manufacturers - has pushed the research and development of power converters towards full scale power conversion, lowered cost pr kW, and increased power density and the need for

F. Blaabjerg; M. Liserre; K. Ma

2011-01-01

407

Multilevel converters for large electric drives  

SciTech Connect

Traditional two-level high frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high frequency switching which produces common-mode voltage and high voltage change (dV/dt) rates to the motor windings. Multilevel inverters solve these problems because their devices can switch at a much lower frequency. Two different multilevel topologies are identified for use as a converter for electric drives, a cascade inverter with separate dc sources and a back-to-back diode clamped converter. The cascade inverter is a natural fit for large automotive all electric drives because of the high VA ratings possible and because it uses several levels of dc voltage sources which would be available from batteries or fuel cells. The back to back diode damped converter is ideal where a source of ac voltage is available such as a hybrid electric vehicle. Simulation and experimental results show the superiority of these two converters over PWM based drives.

Tolbert, L.M.; Peng, F.Z.

1997-11-01

408

A scan converter radar display system  

Microsoft Academic Search

A radar display system, designed to integrate on a single display target information from several radars, has been designed and evaluated. Integration is obtained through the use of single gun scan converter tubes. The resultant image on the TV monitor is a bright steady PPI image which is updated at the end of each radar scan. Limitations imposed on the

N. V. Oneal; P. M. Thiebaud

1975-01-01

409

Fuel densifier converts biomass into fuel cubes  

SciTech Connect

A new cost-effective means to produce clean-burning and low cost commercial and industrial fuel is being introduced by Columbia Fuel Densification Corp., Phoenix. The Columbia Commercial Hydraulic Fuel Densifier converts raw biomass materials such as wood chips, paper, peat moss and rice hulls into densified fuel cubes. The densifier is mobile and its operation is briefly outlined.

Not Available

1982-02-01

410

DC/DC Converter Stability Testing Study.  

National Technical Information Service (NTIS)

This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop os...

B. L. Wang

2008-01-01

411

Multijunction thermal converters by commerical CMOS fabrication  

Microsoft Academic Search

New multijunction thermal converters (MJTCs) fabricated in a commerical CMOS foundry are described. The MJTC is a cantilever structure with a suspended, resistance heating element and thermocouple hot junctions located near the heater on the cantilever. The pit etched below is 150 × 150 ?m in size. The heater structure is composed of a polysilicon resistor and the thermocouples are

Michael Gaitan; John Suehle; Joseph R. Kinard; D. X. Huang

1993-01-01

412

Implementing WCDMA digital up converter in FPGA  

Microsoft Academic Search

This paper will discuss the design and implementation of the digital up converter (DUC) in Field Programmable Gate Array (FPGA). DUC is a digital circuit which generating digital intermediate frequency (IF) signal from low complex digital baseband signal. The DUC provides pulse shaping, interpolation and frequency translation where the up-sampled signal is shifted from centered frequency (0 Hz) to intermediate

N. M. Zawawi; M. F. Ain; S. I. S. Hassan; M. A. Zakariya; C. Y. Hui; R. Hussin

2008-01-01

413

A\\/D converters with midpoint correction  

Microsoft Academic Search

The analog to digital converter (ADC) has been widely used in modern electronic systems and instruments. Characterizing and improving the performances of ADCs has been an active research area for years based on IEEE Standard 1241 (2001), B.E. Peetz et al. (1982), J. Doernberg et al. (1984), G. Chiorboli et al. (1996) and N. Giaquinto et al. (1996). In this

Yih-Chyun Jenq

2003-01-01

414

Achieving capital account convertibility in China  

Microsoft Academic Search

China has been delaying the plan of achieving capital account convertibility since the Asian financial crisis, although restrictions on capital flows have been reduced steadily, confirmed by the falling Capital Account Control Index. Current restrictions exist mainly for cross-border portfolio investment, debt financing and outward direct investment (ODI). Effectiveness of these restrictions, however, has been declining over time. While capital

Yiping Huang; Xun Wang; Qin Gou; Daili Wang

2011-01-01

415

Plasma Energy to Electrical Energy Converter.  

National Technical Information Service (NTIS)

The present invention relates to direct conversion of plasma energy to electrical energy, and more particularly it relates to a converter that separates the charged particles of a plasma produced in a fusion reactor according to the kinetic energy of the ...

R. W. Moir

1974-01-01

416

Regulation of Cuk converters using fuzzy controllers  

Microsoft Academic Search

Synthesis of a control system using a fuzzy inference is proposed for switching regulators. A computer simulation result is given, as an example, where an output voltage of a Cuk converter is regulated by using the proposed fuzzy inference. The simulated waveforms of the output voltage at start-up and the responses to disturbances (variations of the load resistance and of

F. Ueno; T. Inoue; I. Oota; M. Sasaki

1991-01-01

417

Power system applications for PASC converter systems  

Microsoft Academic Search

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source voltage converter systems. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here employs

M. K. Donnelly; R. M. Johnson

1995-01-01

418

Power system applications for PASC converter systems  

Microsoft Academic Search

This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source level voltage converter system. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here

M. K. Donnelly; R. M. Johnson

1994-01-01

419

A new generalized direct matrix converter  

Microsoft Academic Search

In this paper, the authors attempt to introduce a new modulation algorithm for matrix power converters, with an alternative PWM strategy, regardless of type of input and output (AC or DC), and also the number of input and output phases, by using suitable toggling matrix switches, such that favorable output patterns are achieved (with variable amplitudes and frequency). The switch

S. H. Hosseini; E. Babaei

2001-01-01

420

Digital to Analog Converters: a Metrological Overview  

Microsoft Academic Search

In the last years the technology improvement of Digital-to-Analog Converters (DACs) has extended the use of digital techniques in a multitude of applications. Consequently, there is an increasing attention to DAC topics, from researchers and manufacturers. The paper is aimed at providing a metrological overview and the leading trends of the research in the field of DACs.

E. Balestrieri; P. Daponte; S. Rapuano

421

AN/APX-72 Power-Converter.  

National Technical Information Service (NTIS)

This report describes the development of an AC to DC converter from 115VAC to 28 VDC using 60 or 400 cycles. A working unit will be used with the APX-72 Transponder and associated equipment aboard ship permitting operation from the ship's AC power source....

W. Beiles

1966-01-01

422

STIFF: Converting Scientific FITS Images to TIFF  

NASA Astrophysics Data System (ADS)

STIFF is a program that converts scientific FITS1 images to the more popular TIFF2 format for illustration purposes. Most FITS readers and converters do not do a proper job at converting FITS image data to 8 bits. 8-bit images stored in JPEG, PNG or TIFF files have the intensities implicitely stored in a non-linear way. Most current FITS image viewers and converters provide the user an incorrect translation of the FITS image content by simply rescaling linearly input pixel values. A first consequence is that the people working on astronomical images usually have to apply narrow intensity cuts or square-root or logarithmic intensity transformations to actually see something on their deep-sky images. A less obvious consequence is that colors obtained by combining images processed this way are not consistent across such a large range of surface brightnesses. Though with other software the user is generally afforded a choice of nonlinear transformations to apply in order to make the faint stuff stand out more clearly in the images, with the limited selection of choices provides, colors will not be accurately rendered, and some manual tweaking will be necessary. The purpose of STIFF is to produce beautiful pictures in an automatic and consistent way.

Bertin, Emmanuel

2011-10-01

423

Multilevel converters as series VAr compensators  

Microsoft Academic Search

This paper presents experimental results of a multilevel converter applied as a series static VAr compensator (SVS or STATCOM). An outer feedback loop maintains the VAr operating condition and inner feedback loops equalize the DC capacitor voltages. The delta connection of the transformer secondaries provide paths for zero sequence currents to flow. The tests show its capability for operation under

Bakari Mwinyiwiwa; Zbigniew Wolanski; Boon-Teck Ooi; Yiqiang Chen

1997-01-01

424

Ocean tide energy converter having improved efficiency  

Microsoft Academic Search

A tide motor useful for converting periodic rising and falling water levels to useful work such as electric power generation includes a primary piston having a large enclosed chamber that can selectively be filled with air for generation of upward thrust when submerged in rising tidal water or filled with water for generating downward gravitational thrust when the piston is

Rainey

1980-01-01

425

Voltage balancing in DC\\/DC multilevel boost converters  

Microsoft Academic Search

This paper discusses the multilevel boost converter, a DC-DC converter recently proposed. The DC-DC multilevel boost converter is based on one inductor, one switch, 2N-1 diodes and 2N-1 capacitor, for an Nx converter, it is a boost converter able to control and maintain the same voltage in all the N output levels, and able to control the input current. The

Julio C. Rosas-Caro; Juan M. Ramirez; Antonio Valderrabano

2008-01-01

426

Ultrasonic rotary motor using a longitudinal-torsional vibration converter  

Microsoft Academic Search

The characteristics of ultrasonic rotary motors using a converter from longitudinal to torsional vibration are studied. To obtain a rotary motor with large torque, ultrasonic motors using some types of slitted longitudinal-torsional converters are proposed. The longitudinal-torsion vibration converter consists of cylinders with a diagonally slitted vibration-converting part. Ultrasonic motors consist of such a converter with a driving part at

J. Tsujino; M. Takeuchi; H. Koshisako

1992-01-01

427

High Current, Low Voltage Power Converter [20kA, 6V]:LHC Converter Prototype  

Microsoft Academic Search

The superconducting LHC accelerator requires high currents (~12.5kA) and relatively low voltages (~10 V) for its magnets. The need to install the power converters underground is the driving force for reduced volume and high efficiency. Moreover, the LHC machine will require a very high level of performance from the power converters, particularly in terms of DC stability, dynamic response and

H E Jørgensen; Frederick Bordry; A Dupaquier; G Fernqvist

1998-01-01

428

A high efficiency photovoltaic module integrated converter with the asymmetrical half-bridge flyback converter  

SciTech Connect

A module integrated converter (MIC) for a photovoltaic (PV) cell is important part of power conditioning system (PCS). It performs maximum power point tracking of a PV cell to generate the power as much as possible from solar energy. There are several methods for connection between the PV modules and the MICs. In order to avoid partial shading effects, converter-per-module approach was proposed. The MIC that performs maximum power point tracking (MPPT), if it is low efficiency, is no use. The MIC whose output is connected to the output of PV module was proposed for high efficiency. However, there are some problems. In this study, an asymmetrical half-bridge flyback converter is proposed instead of the original flyback converter with same method to solve the problems. The proposed MIC was built to verify the performance. The new topology using soft switching technique showed good performance for the efficiency. At the higher power, the efficiency of the proposed converter is higher than existing converter. (author)

Kim, Heeje; Kim, Jongrak; Shin, Dongsul [Department of Electrical Engineering, Pusan National University, Jangjeon, Geumjeong, Busan 609-735 (Korea); Kim, Hosung; Lee, Kyungjun [Department of Electrical Engineering, Pusan National University, Jangjeon, Geumjeong, Busan 609-735 (Korea); New and Renewable Energy System Research Center, Korea Electro-technology Research Institute, 28-1, Sungju-dong Changwon-si, Kyungsannam-do, 641-120 (Korea); Kim, Jonghyun; Yoo, Dongwook [New and Renewable Energy System Research Center, Korea Electro-technology Research Institute, 28-1, Sungju-dong Changwon-si, Kyungsannam-do, 641-120 (Korea)

2010-08-15

429

The GLAST LAT Silicon Strip Tracker Converter  

SciTech Connect

The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements.

Johnson, R. P. [Physics Department, University of California at Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States); Institute for Particle Physics, University of California at Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States)

2007-07-12

430

Thyristor converter for capacitive laser accumulators  

SciTech Connect

Theoretical and experimental investigations showed the possibility of construction of a thyristor converter for power supply of capacitive accumulators of gas-discharge lamps for a laser with provision for constancy of power consumed from the power source. The curves given for the law of change of energy depending on voltage on the accumulator capacitance and the expressions for current and voltage in the charging circuit make it possible to make an engineer calculation of the circuit of the thyristor converter. The proposed method of calculating the process of charging of a capacitive accumulator can be used for the calculation of a circuit, providing other laws of change of power in time which differ from the law P const.

Benediktov, G.L.

1983-12-01

431

Thyristor converter for capacitive laser accumulators  

NASA Astrophysics Data System (ADS)

Theoretical and experimental investigations showed the possibility of construction of a thyristor converter for power supply of capacitive accumulators of gas-discharge lamps for a laser with provision for constancy of power consumed from the power source. The curves given for the law of change of energy depending on voltage on the accumulator capacitance and the expressions for current and voltage in the charging circuit make it possible to make an engineer calculation of the circuit of the thyristor converter. The proposed method of calculating the process of charging of a capacitive accumulator can be used for the calculation of a circuit, providing other laws of change of power in time which differ from the law P=const.

Benediktov, G. L.

1983-12-01

432

Optical analog-to-digital converter  

DOEpatents

An optical analog-to-digital converter (ADC) is disclosed which converts an input optical analog signal to an output optical digital signal at a sampling rate defined by a sampling optical signal. Each bit of the digital representation is separately determined using an optical waveguide interferometer and an optical thresholding element. The interferometer uses the optical analog signal and the sampling optical signal to generate a sinusoidally-varying output signal using cross-phase-modulation (XPM) or a photocurrent generated from the optical analog signal. The sinusoidally-varying output signal is then digitized by the thresholding element, which includes a saturable absorber or at least one semiconductor optical amplifier, to form the optical digital signal which can be output either in parallel or serially.

Vawter, G. Allen (Corrales, NM); Raring, James (Goleta, CA); Skogen, Erik J. (Albuquerque, NM)

2009-07-21

433

Monolithic and Hybrid Integrated ZB Converter Design  

NASA Astrophysics Data System (ADS)

In this study we have conducted two studies one in hybrid technology and the second one in monolithic technology. We have developed and processed two hybrid microwave converters @ 2.45 GHz. One for large signal applications and the other for small levels of power with 68% as RF-DC conversion efficiency for an input power of 20dBm.Afterwards, to test and validate the rectenna system we have optimised and achieved a 2x2 patch array which was associated to the both rectifiers processed. In order to minimize the RF- DC converter dimensions, we have optimised and developed a monolithic microwave zero bias rectifier @2.45GHz with an efficiency of 60% and 30dBm as a maximum input power using the ED02AH process derived from OMMIC.

Zbitou, J.; Latrach, M.; Toutain, S.

2004-12-01

434

A dual mode forward/flyback converter  

NASA Astrophysics Data System (ADS)

This paper presents a single transistor dc-dc converter that combines both forward and flyback action. The resulting circuit is ohmically isolated and can operate over a wide range of input-to-output voltage ratios. An analysis of the circuit indicates that the forward and flyback portions of the circuit interact to produce three distinct regions of operation. With the design information presented, the circuit can be tailored to utilize the desirable characteristics of either converter action for a specific application. The dynamics of the dual mode circuit are modeled by means of the state-space averaging technique. An ac-dc regulator that takes advantage of the wide operating range of the dual mode circuit operating off the ac line, with only a small input filter, is described.

Park, J. N.; Zaloum, T. R.

435

ZVS Double-Ended ?uk Converter  

Microsoft Academic Search

This brief presents a zero-voltage switching (ZVS) C?uk converter with double-ended rectifier to reduce switching losses on power semiconductors, decrease voltage stresses on rectifier diodes, and achieve power delivery to the output load in both the positive and negative half cycles of the secondary winding voltage. An auxiliary switch and a clamp capacitor are connected in parallel with the primary

Bor-Ren Lin; Yu-Siang Huang

2010-01-01

436

APPARATUS FOR CONVERTING HEAT INTO ELECTRICITY  

DOEpatents

This patent shows an apparatus for converting heat to electricity. It includes a galvanic cell having an anodic metal anode, a fused salt electrolyte, and a hydrogen cathode having a diffusible metal barrier of silver-- palladium alloy covered with sputtered iron on the side next to the fused electrolyte. Also shown is a regenerator for regenerating metal hydride produced by the galvanic cell into hydrogen gas and anodic metal, both of which are recycled. (AEC)

Crouthamel, C.E.; Foster, M.S.

1964-01-28

437

Serum angiotensin converting enzyme in pulmonary disease  

Microsoft Academic Search

Synthetic acylated tripeptides, which may or may not be radiolabelled, are generally used as substrates for measuring serum\\u000a angiotensin converting enzyme (SACE) activity. The capillary endothelial cells are the major source of SACE in normals and\\u000a certain diseased states, however Gaucher’s cells in Gaucher’s disease and epithelioid cells in granulomatous disorders, including\\u000a sarcoidosis, are the major source of enzyme in

P. K. Rohatgi

1982-01-01

438

An overview of sigma-delta converters  

Microsoft Academic Search

Using sigma-delta A\\/D methods, high resolution can be obtained for only low to medium signal bandwidths. This article describes conventional A\\/D conversion, as well as its performance modeling. We then look at the technique of oversampling, which can be used to improve the resolution of classical A\\/D methods. We discuss how sigma-delta converters use the technique of noise shaping in

PERVEZ M. AZIZ; HENRIK V. SORENSEN; JAN VAN DER SPIEGEL

1996-01-01

439

Flower-petal mode converter for NLC  

Microsoft Academic Search

It is important to minimize power loss in the waveguide system connecting klystron, pulse-compressor, and accelerator in an X-Band NLC. However, existing designs of klystron output cavity circuits and accelerator input couplers utilize rectangular waveguide which has relatively high transmission loss. It is therefore necessary to convert to and from the low-loss mode in circular waveguide at each end of

H. A. Hoag; S. G. Tantawi; R. Callin; H. Deruyter; Z. D. Farkas; K. Ko; N. Kroll; T. L. Lavine; A. Menegat; A. E. Vlieks

1993-01-01

440

Fracture imaging with converted elastic waves  

SciTech Connect

This paper examines the seismic signatures of discrete, finite-length fractures, and outlines an approach for elastic, prestack reverse-time imaging of discrete fractures. The results of this study highlight the importance of incorporating fracture-generated P-S converted waves into the imaging method, and presents an alternate imaging condition that can be used in elastic reverse-time imaging when a direct wave is recorded (e.g., for crosswell and VSP acquisition geometries).

Nihei, K.T.; Nakagawa, S.; Myer, L.R.

2001-05-29

441

Superconductor analog-to-digital converters  

Microsoft Academic Search

Ultrafast switching speed, low power, natural quantization of magnetic flux, quantum accuracy, and low noise of cryogenic superconductor circuits enable fast and accurate data conversion between the analog and digital domains. Based on rapid single-flux quantum (RSFQ) logic, these integrated circuits are capable of achieving performance levels unattainable by any other technology. Two major classes of superconductor analog-to-digital converters (ADCs)

OLEG A. MUKHANOV; DEEPNARAYAN GUPTA; ALAN M. KADIN; VASILI K. SEMENOV

2004-01-01

442

32 CFR 538.4 - Convertibility of military payment certificates.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Convertibility of military payment certificates. 538.4 Section...DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS MILITARY PAYMENT CERTIFICATES § 538.4 Convertibility of military payment certificates. (a) For...

2010-07-01

443

32 CFR 538.4 - Convertibility of military payment certificates.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Convertibility of military payment certificates. 538.4 Section...DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS MILITARY PAYMENT CERTIFICATES § 538.4 Convertibility of military payment certificates. (a) For...

2009-07-01

444

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

445

7 CFR 12.32 - Converted wetland identification criteria.  

Code of Federal Regulations, 2012 CFR

(a) Converted wetland shall be identified by determining whether the wetland was altered so as to meet the definition of converted wetland. In making this determination, the following factors are to be...

2012-01-01

446

7 CFR 12.32 - Converted wetland identification criteria.  

Code of Federal Regulations, 2012 CFR

(a) Converted wetland shall be identified by determining whether the wetland was altered so as to meet the definition of converted wetland. In making this determination, the following factors are to be...

2013-01-01

447

Incremental Language Conversion Method to Convert C++ into Ada95.  

National Technical Information Service (NTIS)

This thesis develops a methodology to incrementally convert a legacy object oriented C++ application into Ada95. Using the experience of converting a graphic application, called Remote Debriefing Tool (RDT), in the Graphics Lab of the Air Force Institute ...

D. Sheu

1995-01-01

448

38 CFR 9.11 - Criteria for reinsurers and converters.  

Code of Federal Regulations, 2013 CFR

... false Criteria for reinsurers and converters. 9.11 Section 9.11 Pensions, Bonuses, and Veterans' Relief DEPARTMENT...LIFE INSURANCE AND VETERANS' GROUP LIFE INSURANCE § 9.11 Criteria for reinsurers and converters. The...

2013-07-01

449

Applications and Benefits of Catalytic Converter Thermal Management.  

National Technical Information Service (NTIS)

A catalytic converter thermal management system (TMS) using variable-conductance vacuum insulation and phase-change thermal storage can maintain the converter temperature above its operating temperature for many hours, allowing most trips to begin with mi...

S. D. Burch M. A. Keyser C. P. Colucci T. F. Potter D. K. Benson J. P. Biel

1996-01-01

450

Applications and benefits of catalytic converter thermal management.  

National Technical Information Service (NTIS)

A catalytic converter thermal management system (TMS) using variable-conductance vacuum insulation and phase-change thermal storage can maintain the converter temperature above its operating temperature for many hours, allowing most trips to begin with mi...

S. D. Burch M. A. Keyser C. P. Colucci T. F. Potter D. K. Benson

1996-01-01

451

3. Rear (north) and east elevations of converted chicken house, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Rear (north) and east elevations of converted chicken house, with smokehouse, cooling (well) house, and residence in background - Henry E. Williams Farmstead, Converted Chicken House, East of Residence & Smokehouse, Cedar Point, Chase County, KS

452

7 CFR 12.32 - Converted wetland identification criteria.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Converted wetland identification criteria. 12.32 Section 12...Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Wetland Conservation § 12.32 Converted wetland...

2010-01-01

453

7 CFR 12.32 - Converted wetland identification criteria.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Converted wetland identification criteria. 12.32 Section 12...Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Wetland Conservation § 12.32 Converted wetland...

2009-01-01

454

High Current, Low Voltage Power Converter [20kA, 6V] - LHC Converter Prototype  

NASA Astrophysics Data System (ADS)

The superconducting LHC accelerator requires high currents (approximately 12.5 kA) and relatively low voltages (approximately 10 V) for its magnets. The need to install the power converters underground is the driving force for reduced volume and high efficiency. Moreover, the LHC machine will require a very high level of performance from the power converters, particularly in terms of DC stability, dynamic response and also in matters of EMC. To meet these requirements soft-switching techniques will be used. This paper describes the development of a [20kA, 6V] power converter intended as a stable high-current source for DCCT calibration and an evaluation prototype for the future LHC converters. The converter is made up using a modular concept where five current sources [4kA, 6V] are placed in parallel. The 4 kA sources are configured in plug-in modules : a diode rectifier on the AC mains with a damped L-C passive filter, a Zero Voltage Switching inverter working at 20 kHz and an output stage with high frequency transformers, Schottky rectifiers and output filters. The obtained performance (DC stability, bandwidth, efficiency, EMC,...) is presented and discussed.

Bordry, F.; Dupaquier, A.; Fernqvist, G.; Jorgensen, H. E.; Madsen, P.; Steinmann, E.

1997-05-01

455

High power density dc/dc converter: Selection of converter topology  

NASA Astrophysics Data System (ADS)

The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

Divan, Deepakraj M.

1990-01-01

456

Design of low cost power Converter system for fuel cell  

Microsoft Academic Search

This paper studies the design of DC-DC Converter to convert low-voltage energy sources generated from renewable power like battery power, photovoltaic power, or fuel cells into high-voltage ones. The circuit topology of H-bridge converter to convert input voltage, 24 V, into out voltage, 270 V, was realized through applying phase shift angle control so as to manage electric power and

Taeuk Jung; Juyong Kim; Cheol Choi

2009-01-01

457

A study of volume vs. frequency for soft switching converters  

Microsoft Academic Search

The present study is concerned with determining the volume vs. frequency for the 6 kW converters with forced-air cooling. Both circuits have the same physical layout, but one is operated as a zero-voltage-switching\\/zero-current-switching (ZVS\\/ZCS) converter while the other is operated as a more conventional phase-shift converter. Since the switching losses are lower for the ZVS\\/ZCS converter, its optimum frequency is

B. J. Masserant; E. W. Beans; T. A. Stuart

1992-01-01

458

A comparison of half-bridge resonant converter topologies  

Microsoft Academic Search

The half-bridge series-resonant, parallel-resonant, and combination series-parallel resonant converters are compared for use in low-output-voltage power supply applications. It is shown that the combination series-parallel converter, which takes on the desirable characteristics of the pure series and the pure parallel converter, avoids the main disadvantages of each of them. Analyses and breadboard results show that the combination converter can run

R. L. Steigerwald

1988-01-01

459

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

460

Efficient Output Mode Converter for 30 GHz Gyroklystron at IAP  

Microsoft Academic Search

An output mode converter for Ka-band multi-MW gyroklystron in the Institute of Applied Physics (IAP) operating in the TE53 mode is suggested. Two variants of the converter, aimed for different applications, are presented: the TE53 to TE01 mode converter with power output along the device axis and the TE53 mode to Gaussian wavebeam quasi-optical converter with a visor. The suggested

Sergey V. Kuzikov; Mikhail E. Plotkin; Nikolay I. Zaitsev

2010-01-01

461

A fuzzy controller for DC-DC converters  

Microsoft Academic Search

A controller for DC-DC converters based on fuzzy logic is proposed. Being free of complex equations and heavy computation, the controller is expected to control converters that operate at high frequencies. This paper presents the derivation of fuzzy control rules for the basic converter circuits and simulations of the performance of the closed-loop converters in respect of start-up transient, load

W. C. So; C. K. Tse; Y. S. Lee

1994-01-01

462

An ac-ac power converter for custom power applications  

SciTech Connect

A versatile ac-ac converter that can be utilized as a control device for Custom Power applications is presented. The converter has the ability to regulate bus voltage through voltage sags and overvoltages, and act as a solid state circuit breaker. Performance characteristics under typical conditions are presented along with experimental verification of converter operation. Technical feasibility, projected efficiency and other practical implementation issues are discussed. Operation of the power converter is illustrated using EMTP simulations.

Venkataramanan, G. [Montana State Univ., Bozeman, MT (United States). Dept. of Electrical Engineering; Johnson, B.K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering; Sundaram, A. [Electric Power Research Inst., Palo Alto, CA (United States)

1996-07-01

463

Limiting efficiency of coupled thermal and photovoltaic converters  

Microsoft Academic Search

This paper presents a general energetic and entropic analysis of ideal photovoltaic and solar-thermal converters. Its purpose is to determine the efficiency limit when both types of converters operate together (hybrid converters). It has been found that, while in practical cases hybrid converters may give very high efficiency (61.7% vs. 40.0% of the solar thermal at 500K and 40.7% of

Antonio Luque; Antonio Mart??

1999-01-01

464

An improved RNS reverse converter for the {2  

Microsoft Academic Search

In this paper, we propose a novel high speed memoryless reverse converter for the moduli set {22n+1-1, 2n, 2n-1}. First, we simplify the traditional Chinese Remainder Theorem in order to obtain a reverse converter that only requires arithmetic mod-(22n+l -1). Second, we further improve the resulting architecture to obtain a purely adder based reverse converter. The proposed converter has a

Kazeem Alagbe Gbolagade; Ricardo Chaves; Leonel Sousa; Sorin Dan Cotofana

2010-01-01

465

Voltage balanced multilevel voltage source converter system  

DOEpatents

Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

Peng, F.Z.; Lai, J.S.

1997-07-01

466

Voltage balanced multilevel voltage source converter system  

DOEpatents

A voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means.

Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

1997-01-01

467

Small-Signal Domain Analysis of Digitally Controlled Converters  

Microsoft Academic Search

As the performance of microcontrollers has increased rapidly during the last decade, there is a growing interest to replace the analog controllers in low power switching converters by more complicated and flexible digital control algorithms. Compared to high power converters, the control loop bandwidths for converters in the lower power range are generally much higher. Because of this, the dynamic

D. M. VandeSype; K. DeGusseme; F. M. L. L. DeBelie; A. P. VandenBossche; J. A. Melkebeek

2006-01-01

468

Comparison of capacitively and inductively coupled parallel resonant converters  

Microsoft Academic Search

Both the capacitively and the inductively coupled parallel resonant converters are analyzed by means of the state-plane technique. Based on the results of the analysis, a set of characteristic curves for the converters operated in the continuous conduction mode is presented. These curves can be used to facilitate the analysis and design for such converters. The circuit performances of these

Rui Liu; I. Batarseh; C. Q. Lee

1993-01-01

469

Soft-switched DC\\/DC converter with PWM control  

Microsoft Academic Search

In this paper, a new power converter with two variations is proposed. A novel asymmetrical pulse-width-modulation (PWM) control scheme is used to control the power converter under constant switching frequency operation. The modes of operation for both variations are discussed. The DC characteristics, which can be used in the design of the power converters, are also presented. Two 50 W

Ramesh Oruganti; Phua Chee Heng; Jeffrey Tan Kian Guan; Liew Ah Choy

1998-01-01

470

A general computer algorithm for analysis of switching converters  

Microsoft Academic Search

A general computer algorithm for the analysis of switching power converters and a software tool called SCAT (switching converter analysis tool) is introduced. The algorithm is fast and efficient because it is based on averaging techniques, but it is sufficiently accurate. In addition, it is so general that any type of converter can be analyzed

Masatoshi NAKAHARA; Tamotsu NINOMIYA

1992-01-01

471

Development of a Unipolar Converter for Variable Reluctance Motor Drives  

Microsoft Academic Search

A new converter concept for driving the switched reluctance motor has been developed. This converter has only one switching device per phase, uses a unipolar dc supply, returns all the trapped energy to the source, and does not require bifilar windings; it is called a C-dump converter because the trapped energy is dumped in a capacitor and then returned to

Mehrdad Ehsani; James T. Bass; Timothy J. E. Miller; Robert L. Steigerwald

1987-01-01

472

26 CFR 1.305-6 - Distributions of convertible preferred.  

Code of Federal Regulations, 2010 CFR

...convertible into class A stock for a period of 20...extent to which the stock will be converted...it is impossible to predict the extent to which the class B stock will be converted into...slightly higher than the market price of class A...

2010-04-01

473

26 CFR 1.305-6 - Distributions of convertible preferred.  

Code of Federal Regulations, 2010 CFR

...convertible into class A stock for a period of 20...extent to which the stock will be converted...it is impossible to predict the extent to which the class B stock will be converted into...slightly higher than the market price of class A...

2009-04-01

474

A direct frequency converter controlled by space vectors  

Microsoft Academic Search

Frequency converters have received considerable attention during the past decade. To improve price, volume, weight, reliability, and performance, the trend has been set to rely mainly on semiconductors while removing unnecessary passive components. Among the various converter structures proposed to compete with rectifier-inverter structures, direct frequency converters share the capability of integrating high-tech semiconductors and advanced PWM techniques. A space

E. P. Wiechmann; J. R. Espinoza; L. D. Salazar; J. R. Rodriquez

1993-01-01

475

A Series-Connected Hybrid Triple Converter System  

NASA Astrophysics Data System (ADS)

A hybrid converter system aims at a large capacity high voltage high efficiency converter system with being free from harmonics in the output. The system can consist of n GTO converters and a single NPC IGBT converter connected series by n+1 output transformers. It is proved that a triple converter system consists of two GTO converters and one IGBT converter is most feasible based on the performance evaluation. Thus, this paper treats a triple converter system in detail. The GTO converters operate in a square-wave switching mode, while the IGBT converter operates in a PWM switching mode. The former produces a base part of the total output voltage. The latter not only produces an additional part of the total output, but offsets the harmonic components generated by the GTO converters. The control strategy for the system is proposed, and the experiments on inverter, rectifier and STATCOM operation are demonstrated. The experimental results verified the validity of the proposed hybrid triple converter configuration and its control strategy.

Li, Dongsheng; Fukuda, Shoji; Kubo, Yusuke

476

Power converter simulation module connected to the EMTP  

Microsoft Academic Search

A novel approach for power converter simulation in the electromagnetic transients program (EMTP) is presented. It is based on simultaneous interfacing of a converter simulation module with the EMTP network equations. Hybrid analysis, demonstrated to be more general than the compensation method, is used to model the nonlinear converter module network. The procedure used to formulate hybrid port equations is

J. Mahseredjian; S. Lefebvre; D. Mukhedkar

1991-01-01

477

The THEK program for solar energy plants with 'distributed' converters  

Microsoft Academic Search

The THEK development program for solar energy plants in the medium-power (100 kW) range is discussed. 'Distributed' heliothermal converters in modular units will be used to convert solar energy to heat, most of which will be used at a cascade of decreasing temperatures to meet as many energy needs as possible. Some thermal energy will be converted to electricity to

G. Peri

1979-01-01

478

Multimodular multilevel converters with input\\/output linearity  

Microsoft Academic Search

Multilevel converters constitute the key technology of power electronics to reach the high power ratings required by controllers of flexible AC transmission systems (FACTS). This paper shows that the sinusoidal pulsewidth modulation (SPWM) technique, as applied to multilevel converters, inherently requires a high switching rate. The paper then presents a strategy based on multiple modules of multilevel converters which operate

Bakari Mwinyiwiwa; Zbigniew Wolanski; Yiqiang Chen; Boon-Teck Ooi

1997-01-01

479

Research on a Novel Interleaved Flyback DC\\/DC Converter  

Microsoft Academic Search

Flyback converter has been widely used in low-power applications because of its relative simplicity when compared with other topologies. This paper proposes a novel interleaved flyback DC\\/DC converter, which provides the additional benefit of recycling transformer leakage inductance energy and reducing voltage stress of the power switches. Its input and output current ripple is much smaller than basic flyback converter.

Hongmei Wang; Chunying Gong; Haixiao Ma; Yangguang Yan

2006-01-01

480

A modified flyback DC-DC converter topology  

Microsoft Academic Search

This paper proposes a modified flyback converter topology, its steady state analysis at constant frequency and a control strategy in variable frequency constant ripple mode of operation. The transient characteristics of the converter with proposed variable frequency control law has fast dynamics. That is, the output voltage remains almost constant for any change in load and supply voltage. The converter

R. K. Singh; A. Joshi; Arindam Ghosh

1998-01-01

481

Novel Forward–Flyback Hybrid Bidirectional DC–DC Converter  

Microsoft Academic Search

This paper presents a novel topology named forward-flyback bidirectional DC-DC converter (BDC), which is a hybrid of forward and flyback converters. The windings of forward and flyback transformers are connected in series on the primary side and in parallel on the secondary side. The proposed converter has no startup problem and no high voltage spikes on the switches, which otherwise

Fanghua Zhang; Yangguang Yan

2009-01-01

482

Use of a Converted Magnetron for Making Electric Generator with Radioisotopes or a Converting Cell of the Fission Nuclear Energy.  

National Technical Information Service (NTIS)

The principle of the electric generator with radioisotopes as well as of the converting cell of the fission nuclear energy using a modified magnetron is explained. Both the electric generator with radioisotopes and the converting cell of the fission nucle...

G. Cristea G. Fratiloiu

1975-01-01

483

A current-sourced DC-DC converter derived via the duality principle from the half-bridge converter  

Microsoft Academic Search

A current-sourced switch-mode power supply topology is developed by applying a duality principle to a voltage-sourced half-bridge converter. The converter has boost converter characteristics and is suited to low-voltage high-current input applications. It is shown to compare favorably with the center-tapped transformer converter. Two optional enhancements-nondissipative snubber networks and inductor clamping windings-are also examined. Some results obtained with a low-power

Peter J. Wolfs

1993-01-01

484

Mode-converted diffuse ultrasonic backscatter.  

PubMed

Diffuse ultrasonic backscatter describes the scattering of elastic waves from interfaces within heterogeneous materials. Previously, theoretical models have been developed for the diffuse backscatter of longitudinal-to-longitudinal (L-L) wave scattering within polycrystalline materials. Following a similar formalism, a mode-conversion scattering model is presented here to quantify the component of an incident longitudinal wave that scatters and is converted to a transverse (shear) wave within a polycrystalline sample. The model is then used to fit experimental measurements associated with a pitch-catch transducer configuration performed using a sample of 1040 steel. From these measurements, an average material correlation length is determined. This value is found to be in agreement with results from L-L scattering measurements and is on the order of the grain size as determined from optical micrographs. Mode-converted ultrasonic backscatter is influenced much less by the front-wall reflection than an L-L measurement and it provides additional microstructural information that is not accessible in any other manner. PMID:23927097

Hu, Ping; Kube, Christopher M; Koester, Lucas W; Turner, Joseph A

2013-08-01

485

Tracking with converted position and Doppler measurements  

NASA Astrophysics Data System (ADS)

In many target tracking applications, estimation of target position and velocity is performed in Cartesian coordinates. Use of Cartesian coordinates for estimation stands in contrast to the measurements, which are traditionally the range, azimuth and elevation measurements of the spherical coordinate system. It has been shown in previous works that the classical nonlinear transformation from spherical to Cartesian coordinates introduces a bias in the position measurement. Various means to negate this bias have been proposed. In many active sonar and radar applications, the sensor also provides a Doppler, or equivalently range rate, measurement. Use of Doppler in the estimation process has also been proposed by various authors. First, the previously proposed unbiased conversions are evaluated in dynamic situations, where the performance of the tracking filter is affected by the correlation between the filter gains and the errors in the converted position measurements. Following this, the "decorrelated unbiased converted measurement" approach is presented and shown to be superior to the previous approaches. Second, an unbiased conversion is derived for Doppler measurements from a moving platform.

Bordonaro, Steven V.; Willett, Peter; Bar-Shalom, Yaakov

2011-09-01

486

Forback DC-to-DC converter  

NASA Astrophysics Data System (ADS)

A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

Lukemire, Alan T.

1993-03-01

487

Forback DC-to-DC converter  

NASA Astrophysics Data System (ADS)

A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

Lukemire, Alan T.

1995-05-01

488

Torque converter and assembly utilizing same  

SciTech Connect

This patent describes a torque converter for converting a first torque to a second torque. It comprises: a housing; an input shaft having the first torque; a driving sun gear rotatable about a first axis, the input shaft being coupled to the sun gear; a driven carrier including a shaft portion rotatable about the first axis; a first planetary shaft mounted on the driven carrier coaxillay with a second axis parallel to the first axis; a first planetary gear meshing with and driven by the sun gear and mounted on the first planetary shaft so that the first planetary gear is rotatable about the second axis; a first mass eccentric to the second axis and coupled to the first planetary gear for rotation together about the second axis; first and second unidirectional clutches connected to the shaft portion of the driven carrier and operating in opposite directions; an output torque shaft, one if the first and second unidirectional clutches being coupled to the output torque shaft to transmit the second torque thereto in a pulsating fashion and to permit continuous rotation of the output torque shaft and the other one of the first and second unidirectional clutches being connected to the housing to transmit an algebraic addition of the first and second torques together.

Pitassi, V.E.; Fernandez, A.

1989-12-26

489

Prototype of Free Piston Stirling Converter for Household Use  

NASA Astrophysics Data System (ADS)

A test model of a free piston Stirling engine (FPSE) converter was developed as a heat-to-electricity power converter for a demonstration of solar heat energy utilization at the Japan Aerospace Exploration Agency, for future aerospace applications. The target performance of the converter was 200 W electrical power output and 20% overall efficiency. A bench test of the converter was conducted to evaluate performance. The converter showed good performance as expected. In addition, the characteristics of the FPSE were investigated. Based on these achievements, prototype models of the FPSE for household use were designed and tested as part of a project supported by the New Energy and Industrial Technology Development Organization.

Hoshino, Takeshi; Yoshihara, Shoichi; Akazawa, Teruyuki; Murao, Keiji

490

Trans-Linked Single Phase Interleaved PFC Converter  

NASA Astrophysics Data System (ADS)

The novel trans-linked single phase interleaved PFC converter suitable for the plug-in hybrid electric vehicle is proposed in this paper. The proposed trans-linked PFC converter can achieve the miniaturized performance for its scale and weight. As compared with the conventional single phase PFC converter, the core size and the value of the smoothing capacitor in the proposed trans-linked PFC converter is less than 1/2 that in the conventional one. Though the miniaturized performance, the proposed trans-linked PFC converter can be operated under the control system of the conventional interleaved single phase PFC converter. The operation characteristics and performances of the proposed trans-linked PFC converter is evaluated and discussed with experimental results.

Yamamoto, Masayoshi; Horii, Hiroyuki

491

Bifurcation behaviours of peak current controlled PFC boost converter  

NASA Astrophysics Data System (ADS)

Bifurcation behaviours of the peak current controlled power-factor-correction (PFC) boost converter, including fast-scale instability and low-frequency bifurcation, are investigated in this paper. Conventionally, the PFC converter is analysed in continuous conduction mode (CCM). This prevents us from recognizing the overall dynamics of the converter. It has been pointed out that the discontinuous conduction mode (DCM) can occur in the PFC boost converter, especially in the light load condition. Therefore, the DCM model is employed to analyse the PFC converter to cover the possible DCM operation. By this way, the low-frequency bifurcation diagram is derived, which makes the route from period-double bifurcation to chaos clear. The bifurcation diagrams versus the load resistance and the output capacitance also indicate the stable operation boundary of the converter, which is useful for converter design.

Ren, Hai-Peng; Liu, Ding

2005-07-01

492

On Designs of Radix Converters Using Arithmetic Decompositions--Binary to Decimal Converters  

Microsoft Academic Search

In digital signal processing, radixes other than two are often used for high-speed computation. In the computa- tion for finance, decimal numbers are used instead of bi- nary numbers. In such cases, radix converters are neces- sary. This paper considers design methods for binary to q- naryconverters. It introduces a new design technique based on weighted-sum (WS) functions. The method

Yukihiro Iguchi; Tsutomu Sasao; Munehiro Matsuura

2007-01-01

493

Fluid energy converting method and apparatus  

SciTech Connect

A method and apparatus are disclosed for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

Arnold, L.

1980-01-22

494

Fluid energy converting method and apparatus  

SciTech Connect

There is disclosed a method and apparatus for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

Arnold, L.

1982-08-31

495

Catalytic converter for a diesel engine  

SciTech Connect

A catalytic converter is described for a diesel engine comprising at least two metal strips having a plurality of indentations, the indentations being of substantially equal height so that the spacing between the strips is equal to this height, the indentations in adjacent strips being offset so that the adjacent strips cannot coincide and nest together, the indentation being aligned transversely to the direction of flow of exhaust gas from the engine, the indentations being staggered, the indentations and the strips defining a tortuous flow path, between the strips, for exhaust gas from the engine, the tortuous flow path including a least one generally right-angle bend relative to the initial direction of flow of gas from the engine, and wherein the metal strips are coated with a combustion catalyst.

Retallick, W.B.

1986-07-01

496

[Convertible energy sources in Neisseria gonorrhoeae].  

PubMed

Availability of two major sources of convertible energy in gonococci--the intracellular pool of ATP and electrochemical potential of hydrogen ions--has been established. ATP synthesis occurs when inducing membrane potential by creation of K+ gradient with presence of valinomycin and when inducing the proton gradient. Transmembrane difference of electric potentials has been determined which changes within 103-145 mV under the increase of pH from 5.0 to 8.0, and concentration gradient of protons decreases from 80 to 47 mV. The proton-motive force value remains unchanged (183-192 mV) in the range of pH 5.0-8.0. PMID:15554294

Skliar, T V; Vinnikov, A N

497

Serum angiotensin converting enzyme in pneumonias.  

PubMed Central

Serum concentrations of angiotensin converting enzyme (ACE) were studied in pneumonias caused by different pathogens and in cases in which the aetiology could not be defined. In all aetiological groups, except in viral pneumonia, there was a significant increase in ACE during recovery (p less than 0.001). In several patients the lowest values during the acute phase of disease and the highest values during recovery were outside the reference limits. In cases with known aetiology the highest ACE values and the difference between the lowest and the highest values correlated positively with C-reactive protein concentrations at admission (p less than 0.001). The pathophysiology behind the fluctuations of the ACE concentrations is unknown.

Kerttula, Y; Weber, T H

1986-01-01

498

A 60 channel PCM-ADPCM converter  

NASA Astrophysics Data System (ADS)

Coding techniques based on adaptive linear prediction and quantization are well suited to signals carried by telephone channels and can provide, with a per channel rate of 32 kbits/s, a level of quality compatible with the specifications of the conventional 64 kbit/s rate. The ADPCM technique described in this paper features a simple adaptive quantization scheme and a tenth-order linear prediction adaptive filter realized as a cascade of five second-order sections. Besides superior performance characteristics, the nonaccumulation of degradations in tandem connections is achieved. The implementation is a 60 channel PCM-ADPCM converter, called TMN 162. It is a fully digital equipment which offers a doubling of the capacity of digital links in telephone networks.

Raulin, J.-M.; Bonnerot, G.; Jeandot, J.-L.; Lacroix, R.

1982-04-01

499

Converting low dose radiation to redox signaling  

PubMed Central

In contrast to the damaging effects of high doses, low dose radiation (UV, gamma) has been reported to provoke constructive changes in plants. However, the mechanisms by which plants recognize and respond to low dose radiation are not understood. We have shown recently that polygalacturonic acid, cell wall polysaccharide, converts the highly reactive product of radiation - hydroxyl radical into superoxide which may be further dismutated to hydrogen peroxide. Superoxide has been proposed to act as a signaling molecule, while hydrogen peroxide is known to be the key species in redox signaling cascades which are involved in the regulation of various physiological processes. Hence we propose that polygalacturonic acid may operate as radiation-signaling convertor. The outlined principles of radiation-sensing could also be valid for mammalian cells, with some other molecules mediating the conversion.

Pristov, Jelena Bogdanovic; Spasic, Mihajlo; Spasojevic, Ivan

2013-01-01

500

Converting a fuel to combustible gas  

SciTech Connect

A sulfur-containing fuel is passed into a first fluidized bed containing CaSO/sub 4/ and CaO and an oxygen-transfer mediator (e.g. H/sub 2/) whereby the fuel is converted to combustible gas, some CaSO/sub 4/ being reduced to CaS and sulfur being fixed as CaS by reaction with CaO. Bed particles pass from the bottom layer of the first bed into the bottom layer of the second bed which is fluidized by air at conditions such that some, but not all of the CaS is selectively oxidized to CaSO/sub 4/ with no liberation of sulfur moieties. Bed particles pass from the bottom layer of second bed to the bottom layer of a third bed optionally after passage via a fourth bed between the second and third beds. In the third bed particles are fluidized with air to convert CaS selectively to CaSO/sub 4/ with no liberation of sulfur moiety whereby to raise the particles' temperature sufficiently above that of the first bed that particles passing from the bottom layer of the third bed into the bottom layer of the first bed provide sufficient sensible heat to maintain the fuel conversion temperature of the first bed. In the fourth bed particles are fluidized with air under such conditions that sulfur moiety is liberated, preferably at a rate which approximately equals the rate of sulfur-capture in the first bed whereby to maintain approximately a constant amount of reactive CaO in the beds for sulfur-capture in the first bed.

Moss, G.

1985-04-02