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High Voltage Rectification

Description: Introduction: "This meeting was called by Mr. S. H. Smiley in order to review progress made on the corrosion problem since the last meeting on September 5th, and to devise a definite program on the specific problem of the corrosion of the coolant coolers. The minutes of the last meeting were reviewed briefly and it was pointed out that neither the corrosion of the water piping nor the hot water tanks presented any immediate concern. The chief concern then is with the excessive pitting of the cooler shells as disclosed in E.T.4I's. reports on those coolers which were removed for inspection."
Date: 1945
Creator: Nelson, Walter H.
Partner: UNT Libraries Government Documents Department

Recovery Act: High-Efficiency, Wideband Three-Phase Rectifiers and Adaptive Rectifier Management for Telecomm Central Office and Large Data Center Applications

Description: Lineage Power and Verizon teamed up to address a DOE funding opportunity focused on improving the power conversion chain in telecommunications facilities and data centers. The project had three significant elements: the design and development of high efficiency and high power three-phase rectifiers by Lineage Power, design and development of software to optimize overall plant energy efficiency by Lineage Power, and a field trial in active Verizon telecommunications facilities where energy consumption was measured before and after efficiency upgrades.
Date: June 29, 2012
Creator: Johnson, Mark A.
Partner: UNT Libraries Government Documents Department

Evaluation of dynamic and static electrical characteristics for the DY8 and YI8 process gallium diodes in comparison to the DI8 process boron diodes.

Description: A rectifier is an electrical device, comprising one or more semiconductor devices arranged for converting alternating current to direct current by blocking the negative or positive portion of the waveform. The purpose of this study would be to evaluate dynamic and static electrical characteristics of rectifier chips fabricated with (a) DY8 process and (b) YI8 process and compare them with the existing DI8 process rectifiers. These new rectifiers were tested to compare their performance to meet or exceed requirements of lower forward voltages, leakage currents, reverse recovery time, and greater sustainability at higher temperatures compared to diodes manufactured using boron as base (DI8 process diodes) for similar input variables.
Access: This item is restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2006
Creator: Dhoopati, Swathi
Partner: UNT Libraries

THz transceiver characterization : LDRD project 139363 final report.

Description: LDRD Project 139363 supported experiments to quantify the performance characteristics of monolithically integrated Schottky diode + quantum cascade laser (QCL) heterodyne mixers at terahertz (THz) frequencies. These integrated mixers are the first all-semiconductor THz devices to successfully incorporate a rectifying diode directly into the optical waveguide of a QCL, obviating the conventional optical coupling between a THz local oscillator and rectifier in a heterodyne mixer system. This integrated mixer was shown to function as a true heterodyne receiver of an externally received THz signal, a breakthrough which may lead to more widespread acceptance of this new THz technology paradigm. In addition, questions about QCL mode shifting in response to temperature, bias, and external feedback, and to what extent internal frequency locking can improve stability have been answered under this project.
Date: September 1, 2009
Creator: Nordquist, Christopher Daniel; Wanke, Michael Clement; Cich, Michael Joseph; Reno, John Louis; Fuller, Charles T.; Wendt, Joel Robert et al.
Partner: UNT Libraries Government Documents Department

Power Supplies for Precooler Ring

Description: Eight power supplies will energize the antiproton Precooler ring. there will be two series connected supplies per quadrant. These supplies will power 32 dipole and 19 quadrupole magnets. The resistance and inductance per quadrant is R = 1.4045 Ohms and L = 0.466. Each powr supply will have 12-phase series bridge rectifiers and will be energized from the 480 V 3-phase grid. The total of eight power supplies are numbered IA, IIA, IIIA, IVA, and IB, IIB, IIIB, and IVB. Each quadrant will contain one A and one B supply. A block diagram of the Precooler ring with its power supplies is shown in Figure 1.
Date: December 12, 1980
Creator: Fuja, Raymond & Praeg, Walter
Partner: UNT Libraries Government Documents Department

GaN High Power Devices

Description: A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers, GaN/AlGaN heterojunction bipolar transistors, GaN heterostructure and metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.
Date: July 17, 2000
Creator: PEARTON,S.J.; REN,F.; ZHANG,A.P.; DANG,G.; CAO,X.A.; LEE,K.P. et al.
Partner: UNT Libraries Government Documents Department

Hybrid high direct current circuit interrupter

Description: A device and a method for interrupting very high direct currents (greater than 100,000 amperes) and simultaneously blocking high voltages (greater than 600 volts). The device utilizes a mechanical switch to carry very high currents continuously with low loss and a silicon controlled rectifier (SCR) to bypass the current around the mechanical switch while its contacts are separating. A commutation circuit, connected in parallel with the SCR, turns off the SCR by utilizing a resonant circuit to divert the SCR current after the switch opens.
Date: December 31, 1996
Creator: Rockot, J.H.; Mikesell, H.E. & Jha, K.N.
Partner: UNT Libraries Government Documents Department

High Voltage GaN Schottky Rectifiers

Description: Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.
Date: October 25, 1999
Creator: CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T. et al.
Partner: UNT Libraries Government Documents Department

Theory of High Frequency Rectification by Silicon Crystals

Description: The excellent performance of British ''red dot'' crystals is explained as due to the knife edge contact against a polished surface. High frequency rectification depends critically on the capacity of the rectifying boundary layer of the crystal. C. For high conversion efficiency, the product of this capacity and of the ''forward'' (bulk) resistance R{sub b} of the crystal must be small. For a knife edge, this product depends primarily on the breadth of the knife edge and very little upon its length. The contact can therefore have a rather large area which prevents burn-out. For a wavelength of 10 cm. the computations show that the breadth of the knife edge should be less than about 10{sup -3} cm. For a point contact the radius must be less than 1.5 x 10{sup -3} cm. and the resulting small area is conductive to burn-out. The effect of ''tapping'' is probably to reduce the area of contact.
Date: October 29, 1942
Creator: Bethe, H.A.
Partner: UNT Libraries Government Documents Department

Progress on PEP-II Magnet Power Conversion System?

Description: The various power systems for supplying the PEP-II DCmagnets rely exclusively on switch mode conversion, utilizing a varietyof means depending on the requirements. All of the larger power supplies,ranging from 10 to 200 kW, are powered from DC sources utilizingrectified 480 V AC. Choppers can be used for the series connectedstrings, but for smaller groups and individual magnets, inverters drivinghigh-frequency transformers with secondary rectifiers comprise the bestapproach. All of the various systems use a "building block" approach ofmultiple standard-size units connected in series or parallel to mostcost-effectively deal with a great range of voltage and currentrequirements. Utilization of existing infrastructure from PEP-I has beena cost-effective determinant. Equipment is being purchased eitheroff-the-shelf, through performance specification, or by hardware purchasebased on design-through-prototype. The corrector magnet power system,utilizing inexpensive, off-the-shelf four-quadrant switching motorcontrollers, has already proven very reliable: 120 of the total of 900units have been running on the injection system for four months with nofailures.
Date: June 1, 1996
Creator: Bellomo, P.; Genova, L.; Jackson, T. & Shimer, D.
Partner: UNT Libraries Government Documents Department

Ac-dc converter firing error detection

Description: 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.
Date: July 15, 1996
Creator: Gould, O.L.
Partner: UNT Libraries Government Documents Department

Design and testing of a 320 MW pulsed power supply

Description: For a 60 Tesla, 100 millisecond long pulse magnet five 64 MW (87.6 MVA) power converter modules have been installed. Each module provides a no-load voltage of 4.18 kV and a full load voltage of 3.20 kV at the rated current of 20 kA. The modules are connected to a 1,430 MVA/650 MJ inertial energy storage generator set, which is operated at 21 kV and frequencies between 60 and 42 Hz. They are designed to provide the rated power output for 2 seconds once every hour. Each module consists of two 21 kV/3.1 kV cast coil transformers and two 6-pulse rectifiers connected in parallel without an interphase reactor, forming a 12-pulse converter module. As far as possible standard high power industrial converter components were used, operated closer to their allowable limits. The converters are controlled by three programmable high speed controllers. In this paper the design of the pulsed converters, including control and special considerations for protection schemes with the converters supplying a mutually coupled magnet system, is detailed. Test results of the converters driving an ohmic-inductive load for 2 seconds at 20 kA and 3.2 kV are presented.
Date: March 1, 1998
Creator: Schillig, J.B.; Boenig, H.J. & Ferner, J.A.
Partner: UNT Libraries Government Documents Department

GaN Electronics For High Power, High Temperature Applications

Description: A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers. GaN/AlGaN heterojunction bipolar transistors and GaN metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.
Date: June 12, 2000
Creator: PEARTON,S.J.; REN,F.; ZHANG,A.P.; DANG,G.; CAO,X.A.; LEE,K.P. et al.
Partner: UNT Libraries Government Documents Department

Digital regulation of a phase controlled power converter

Description: The Relativistic Heavy Ion Collider, now in construction at Brookhaven National Laboratory, will use phase controlled power converters for the main dipole and quadrupole magnet strings. The rectifiers in these power supplies will be controlled by a digital regulator based on the TI 320C30 Digital Signal Processor (DSP). The DSP implements the current loop, the voltage loop, and a system to actively reduce the sub-harmonic ripple components. Digital firing circuits consisting of a phase locked lop and counters are used to fire the SCRs. Corrections for the sub-harmonic reduction are calculated by the DSP and stored in registers in the firing circuit. These corrections are added in hardware, to the over-all firing count provided by the DSP. the resultant count is compared to a reference counter to fire the SCRs. This combination of a digital control system and the digital firing circuits allows the correction of the sub-harmonics in a real-time sense. A prototype of the regulator has been constructed, and the preliminary testing indicates a sub-harmonic reduction of 60 dB.
Date: December 1, 1995
Creator: Schultheiss, C. & Haque, T.
Partner: UNT Libraries Government Documents Department

Cathodic protection -- Addition of 6 anodes to existing rectifier 31

Description: This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the cathodic protection system additions are installed, connected, and function as required by project criteria. The cathodic protection system is for the tank farms on the Hanford Reservation. The tank farms store radioactive wastes.
Date: June 14, 1995
Creator: Lane, W.M.
Partner: UNT Libraries Government Documents Department

Dual Mode Inverter Control Test Verification

Description: Permanent Magnet Motors with either sinusoidal back emf (permanent magnet synchronous motor [PMSM]) or trapezoidal back emf (brushless dc motor [BDCM]) do not have the ability to alter the air gap flux density (field weakening). Since the back emf increases with speed, the system must be designed to operate with the voltage obtained at its highest speed. Oak Ridge National Laboratory's (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has developed a dual mode inverter controller (DMIC) that overcomes this disadvantage. This report summarizes the results of tests to verify its operation. The standard PEEMRC 75 kW hard-switched inverter was modified to implement the field weakening procedure (silicon controlled rectifier enabled phase advance). A 49.5 hp motor rated at 2800 rpm was derated to a base of 400 rpm and 7.5 hp. The load developed by a Kahn Industries hydraulic dynamometer, was measured with a MCRT9-02TS Himmelstein and Company torque meter. At the base conditions a current of 212 amperes produced the 7.5 hp. Tests were run at 400, 1215, and 2424 rpm. In each run, the current was no greater than 214 amperes. The horsepower obtained in the three runs were 7.5, 9.3, and 8.12. These results verified the basic operation of the DMIC in producing a Constant Power Speed Ratios (CPSR) of six.
Date: April 25, 2001
Creator: Bailey, J.M.
Partner: UNT Libraries Government Documents Department

Calibrating Accelerometers Using an Electromagnetic Launcher

Description: A Pulse Forming Network (PFN), Helical Electromagnetic Launcher (HEML), Command Module (CM), and Calibration Table (CT) were built and evaluated for the combined ability to calibrate an accelerometer. The PFN has a maximum stored energy of 19.25 kJ bank and is fired by a silicon controlled rectifier (SCR), with appropriate safety precautions. The HEML is constructed out of G-10 fiberglass and is designed to accelerate 600 grams to 10 meters per second. The CM is microcontroller based running Arduino Software. The CM has a keypad input and 7 segment outputs of the bank voltage and desired voltage. After entering a desired bank voltage, the CM controls the charge of the PFN. When the two voltages are equal it allows the fire button to send a pulse to the SCR to fire the PFN and in turn, the HEML. The HEML projectile's tip hits a target that is held by the CT. The CT consists of a table to hold the PFN and HEML, a vacuum chuck, air bearing, velocity meter and catch pot. The Target is held with the vacuum chuck awaiting impact. After impact, the air bearing allows the target to fall freely for the velocity meter to get an accurate reading. A known acceleration is determined from the known change in velocity of the target. Thus, if an accelerometer was attached to the target, the measured value can be compared to the known value.
Date: May 13, 2012
Creator: Timpson, Erik
Partner: UNT Libraries Government Documents Department

Inductive-storage pulse-circuit device

Description: Inductive storage pulse circuit device is disclosed which is capable of delivering a series of electrical pulses to a load in a sequential manner. Silicon controlled rectifiers as well as spark gap switches can be utilized in accordance with the present invention. A commutation switching array is utilized to produce a reverse current to turn-off the main opening switch. A commutation capacitor produces the reverse current and is initially charged to a predetermined voltage and subsequently charged in alternating directions by the inductive storage current.
Date: January 21, 1982
Creator: Parsons, W.M. & Honig, E.M.
Partner: UNT Libraries Government Documents Department