922 research outputs found
A Compact Integrated High-Voltage Pulser Insensitive to Supply Transients for 3-D Miniature Ultrasound Probes
No full textIn this letter, a compact high-voltage (HV) transmit circuit for dense 2-D transducer arrays used in 3-D ultrasonic imaging systems is presented. Stringent area requirements are addressed by a unipolar pulser with embedded transmit/receive switch. Combined with a capacitive HV level shifter, it forms the ultrasonic HV transmit circuit with the lowest reported HV transistor count and area without any static power consumption. The balanced latched-based level shifter implementation makes the design insensitive to transients on the HV supply caused by pulsing, facilitating application in probes with limited local supply decoupling, such as imaging catheters. Favorable scaling through resource sharing benefits massively arrayed architectures while preserving full individual functionality. A prototype of 8 × 9 elements was fabricated in the TSMC 0.18 μm HV BCD technology and a 160μm×160μm PZT transducer matrix is manufactured on the chip. The system is designed to drive 65-V peak-to-peak pulses on 2-pF transducer capacitance and hardware sharing of six elements allows for an area of only 0.008 mm2 per element. Electrical characterization as well as acoustic results obtained with the 6-MHz central frequency transducer are demonstrated.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationImPhys/Medical Imagin
A Low-Noise HV Interface Circuit for MEMS Vibratory Gyroscope
No full textThe paper presents a low-noise high voltage (HV) CMOS Interface ASIC designed for MEMS vibratory gyroscopes. A closed-loop control is realized in the driving mode. An in-chip level shifter is designed in the loop to achieve a high DC voltage level of 5V which can excite the gyroscope. A DC biasing method is adopted in the interface circuit to convert the amplitude-modulated capacitive signal into voltage. The chip occupies 2.5 X 2.0mm(2) in a 0.35 mu m 2P3M BCD HV process, which offers buried layer and high voltage N-well isolation to block out the potential coupling noise. Simulation results show that the drive axis can accomplish a closed-loop self-oscillation of the MEMS gyroscope.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000304037500035&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicPhysics, AppliedEICPCI-S(ISTP)
Practical application of on-line partial discharge monitoring technique on 500kV shunt reactor
No full textConsidering the damage mechanism of oil-impregnated paper insulation in power transformers, shunt reactors and other high voltage electrical apparatus caused by partial discharge, a concept of “destructive partial discharge” is introduced in this paper. The intensity of this discharge is regarded as several thousands pico-coulomb (pC) and may cause the insulation a fatal damage. An oil-paper insulation is usually able to withstand this type of partial discharge for a period of time prior to failure. This provides engineers a time window to detect it. This paper describes an on-line partial discharge monitoring system for 500kV shunt reactors. The commission results from 3 single-phase shunt reactors either connected or disconnected to the grid showed that the on-line partial discharge detecting system has a high noise immunising ability. Two years later after the installation, a pre-warning signal was received from one shunt reactor indicating the existence of an intermittent discharge. The acoustic emission system located its position at the low end of the high voltage bushing in the oil. Dissolved gasses analysis (DGA) in the oil suggested the presence of partial discharge, as acetylene (C2H2) was as high as 20ppm. PD activity was further confirmed by a physical examination on the reactor
EHV/HV Italian Network Three-Phase Power-Flow by PFPD
No full textIn this paper, the three-phase generalization of a single-phase power flow (named PFPD) developed by the first author is presented. This novel formulation is mainly developed for HV/EHV transmission network applications, but it preserves validity also for distribution power system. The algorithm quantitatively aims at investigating the impact of the asymmetrical transmission structures and unbalanced loads on power systems. This impact is evaluated in terms of voltage sequence components. The algorithm is implemented in Matlab environment and tested by several fictitious networks
The Devil's altar? : crime and the early modern public house
No full textWas the early modern public house really such a dangerous place, as Puritan preachers (and many historians) suggested? This article discusses offences by publicans and patrons. It argues that the evidence for crime needs to be carefully contextualised and that taverns could stabilise as well as threaten the social order
The impacts of short break provision on disabled children and families: an international literature review
No full textFor over 30 years, short breaks have been part of the landscape of support provision for families with a disabled child. Historically, the term ‘respite care’ has been used in much of the research literature concerning short breaks for families with a disabled child. However, ‘short breaks’ has become the preferred term, partly due to the negative connotations of family carers requiring ‘respite’ from their children, and partly because short breaks now encompass a much wider range of supports than out-of-home placement in specialist residential facilities (Cramer and Carlin, 2008). As such, the term ‘short breaks’ will be used throughout this review, with the exception of direct quotes from research studies where the term ‘respite’ is used by study participants or study authors
Investigation of Wireless Power Transfer for Smart Grid On-line Monitoring Devices under HV Condition
No full textAbstractMagnetically coupled resonant wireless power transfer (WPT) has been employed in many applications, such as wireless charging of portable electronic devices and electric vehicles. This technology can also provide solutions for power transfer in complex environment and special scenario with mid-range transfer distance and acceptable transfer efficiency. In this paper, a mid-range WPT system is designed to provide an effective solution for power supply to smart grid on-line monitoring devices in high voltage (HV) on-site condition. Both the model, design, and experimental implementation of a two-coil system are represented. To find out the transfer characteristic of the proposed mid-range WPT system, the circuit model, exciting frequency, coupling, output power and transfer efficiency are analyzed based on the circuit and magnetic principles. Some key points about the optimal working area for the mid-range WPT system are demonstrated. Finally, a prototype system with transfer distance 1.1 meter for 110kV HV power cables is built to verify the effectiveness of the regular law of system. By carefully tuning the circuit parameters, the prototype is able to deliver 20W power through 1.1 meter distance with 20.23% efficiency
Comparison of Pulse Current Capability of Different Switches for Modular Multilevel Converter-based Arbitrary Wave shape Generator used for Dielectric Testing of High Voltage Grid Assets
No full textThis article compares the pulse current capability of various Semiconductor (SM) device technologies for Modular Multilevel Converter (MMC)-based High Voltage (HV) Arbitrary Waveform Generator (AWG) for dielectric testing of grid assets to find the most suitable SM device technology which can perform well in generating lightning impulse that demands a high peak current for a relatively short time. For the typical HV loads of the AWG, Lightning Impulse (LI) test may require a pulse current to rise to 1.7 kA in 0.2 µs. It is essential to highlight that most other dielectric tests performed with an HV AWG demand a relatively low current such as less than 10 A. Therefore, TO-packaged semiconductors would be well-suited for a large number of tests other than short impulses. To optimize the size and cost of the HV AWG, this paper evaluates the pulse current capabilities of TO-packaged semiconductors for the above-mentioned current requirement to generate LI waveform. The first comparison is made among Non-Punch Through (NPT) Si IGBT, Field Stop (FS) Si IGBT, Si MOSFET, and SiC MOSFETs with roughly the same current rating of 40 A. It is found that the Si MOSFET gives the fastest rise time of 0.42 µs and the NPT IGBT gives the highest current amplification factor of almost 12 times greater than its own rated current. However, 3rd Generation SiC MOSFET combines Si MOSFET and NPT IGBT capabilities to generate a fast rise time and high peak pulse current. Additionally, the FS IGBT is compared with the SiC MOSFET. The SiC MOSFET performs better in peak current capability and the obtained rise time. All in all, the research results and the stringent HV AWG requirements for LI show that the application requires a relatively complex switch implementation with far superior current capability than in normal operation. Therefore, a parallel connection of several TO-packaged devices is necessary to generate LI from MMC-based HV AWG.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.DC systems, Energy conversion & Storag
Command and Staff College ´Blago Zadro´ - The Education of Senior HV Officers during The Homeland War
No full textRad "Zapovjedno-stožerna škola 'BlagoZadro' – izobrazba najviših časnika HV-a tijekom Domovinskog rata" će u uvodnom dijelu u najosnovnijim crtama obuhvatiti početnu koncepciju sustava izobrazbe Hrvatske vojske i početnu časničku izobrazbu prije ustrojavanja Zapovjedno-stožerne škole "Blago Zadro", a u glavnom dijelu prikazat će povijesni tijek izobrazbe u školi do kraja 1995. i sve aspekte odgojno-obrazovnog procesa. U radu će biti analizirani svi elementi didaktičko-metodičkog četverokuta, a bit će ukazano i na ograničenja nastavnog procesa i načine na koji su ista rješavana. U radu će biti prikazan i razvoj nastavne institucije i unapređenje nastavnog procesa od I. do IV. naraštaja. Rad je sastavni je dio projekta "Vojna izobrazba HV-a tijekom Domovinskog rata".The paper provides short overview of the beginnings of officer education and describes the outlook of the education system prior to the establishment of the Command and Staff College 'Blago Zadro'. Author describes all the aspects of officer education before the end of 1995 and analyzes all elements of didactical-methodical square. He describes the problems and difficulties within the education process and the ways they were resolved. Furthermore, he presents the establishment of the institution of officer education and the improvements of education process from 1st to 4th officer education class. The paper is written as a part of "Military Education in HV During the Homeland War"
A Front-End ASIC With High-Voltage Transmit Switching and Receive Digitization for 3-D Forward-Looking Intravascular Ultrasound Imaging
No full textThis paper presents an area- and power-efficient application-specified integrated circuit (ASIC) for 3-D forward-looking intravascular ultrasound imaging. The ASIC is intended to be mounted at the tip of a catheter, and has a circular active area with a diameter of 1.5 mm on the top of which a 2-D array of piezoelectric transducer elements is integrated. It requires only four micro-coaxial cables to interface 64 receive (RX) elements and 16 transmit (TX) elements with an imaging system. To do so, it routes high-voltage (HV) pulses generated by the system to selected TX elements using compact HV switch circuits, digitizes the resulting echo signal received by a selected RX element locally, and employs an energy-efficient load-modulation datalink to return the digitized echo signal to the system in a robust manner. A multi-functional command line provides the required sampling clock, configuration data, and supply voltage for the HV switches. The ASIC has been realized in a 0.18-μm HV CMOS technology and consumes only 9.1 mW. Electrical measurements show 28-V HV switching and RX digitization with a 16-MHz bandwidth and 53-dB dynamic range. Acoustical measurements demonstrate successful pulse transmission and reception. Finally, a 3-D ultrasound image of a three-needle phantom is generated to demonstrate the imaging capability.Accepted author manuscriptElectronic InstrumentationImPhys/Acoustical Wavefield Imagin
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