Коммутация энергии тиристорами и транзисторами из низковольтной цепи в высоковольтную в трансформаторных генераторах высоковольтных импульсов

Рассмотрены отличия тиристоров и транзисторов в качестве ключей при коммутации низковольтных цепей для передачи энергии в нагрузку в трансформаторных генераторах высоковольтных импульсов.Differences are considered for thyristors and transistors as keys when switching low voltage circuits to transmit energy in load of transformer high-voltage pulse generators

High frequency AC power converter for low voltage circuits

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 74-76).This thesis presents a novel AC power delivery architecture that is suitable for VHF frequency (50-100MHz) polyphase AC/DC power conversion in low voltage integrated circuits. A complete AC power delivery architecture was evaluated demonstrating the benefits of delivering power across the interconnect at high voltage and lower current with on- or over-die transformation to low voltage and high current. Two approaches to polyphase matching networks in the transformation stage are compared: a 3-phase system with separate single-phase matching networks and individual full bridge rectifiers, and a 3-phase delta-to-wye matching network and a 3-phase rectifier bridge. In addition, a novel switch-capacitor rectifier capable of 3V, 1W output, was evaluated as an alternative circuit to the diode rectifiers. A 50MHz prototype of each version of the system was designed and built for a 12:1 conversion ratio with 24Vpp line-to-line AC input, 2V DC output and 0.7W output power. The measured overall system efficiency is about 63 % for the 3-phase delta system. Although the application is intended for an integrated CMOS implementation, this thesis primarily focuses on discrete PCB level realizations of the proposed architectures to validate the concept and provide insights for future designs.by Nathaniel Jay Tobias Salazar.M.Eng

0.5V 3rd-order Tunable gm-C Filter

This paper proposes a 3rd-order gm-C filter that operates with the extremely low voltage supply of 0.5V. The employed transconductor is capable for operating in an extremely low voltage power supply environment. A benefit offered by the employed transconductor is that the filter’s cut-off frequency can be tuned, through a dc control current, for relatively large ranges. The filter structure was designed using normal threshold transistors of a triple-well 0.13μm CMOS process and is operated under a 0.5V supply voltage; its behavior has been evaluated through simulation results by utilizing the Analog Design Environment of the Cadence software

Voltage regulation considerations for the design of hybrid distribution transformers

The future substation depends on finding a way to mitigate the effects of the drawbacks of the conventional legacy by employing the efficiency of the solid state switches [1]. This paper discusses the considerations of designing a distribution transformer that provides additional functions in regulating the voltage and controlling the reactive power that is injected in the distribution network, using a fractional rated converter attached partially with the windings of the transformer. This approach aims mainly to enhance the unit with more flexibility in controlling the voltage at the last mile of the network, in order to decrease the losses and meet the future expectations for low voltage networks modifications, and that by using a power electronic (PE) approach has less losses and more functionality (depending on the reliability of transformer and intelligence of PE). The design of a hybrid distribution transformer is detailed and its functionality in regulating the voltage is discussed as a combination between the features of one of the most reliable network devices, the transformer, and the effect of PE existence with less losses in both switching and conduction losses. Reduced ratings PE are used in this approach, whereby the solid state switches are controlled according to the immediate need for voltage control in low voltage (LV) networks

Hand-arm vibration disorder among grass-cutter workers in Malaysia

Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand-arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand-arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand-arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers

Development and performance of power processor system for 2-gigahertz, 200-watt amplifier for communications technology satellite

The electrical and environmental requirements for a power processor system (PPS) designed to supply the appropriate voltages and currents to a 200-watt traveling wave tube (TWT) for a communication technology satellite is described. A block diagram of the PPS, the interface requirements between the PPS and spacecraft, the interface requirements between the PPS and 200-watt TWT, and the environmental requirements of the PPS are presented. Also included are discussions of protection circuits, interlocking sequences, and transient requirements. Predictions of the flight performance, based on ground test data, are provided

Supercapacitor assisted LDO (SCALDO) techniquean extra low frequency design approach to high efficiency DC-DC converters and how it compares with the classical switched capacitor converters

Supercapacitor assisted low dropout regulators (SCALDO) were proposed as an alternative design approach to DC-DC converters, where the supercapacitor circulation frequency (switching frequency) is in the order of few Hz to few 10s of Hz, with an output stage based on a low dropout regulator stage. For converters such as 12–5V, 5–3.3V and 5–1.5V, the technique provides efficiency improvement factors of 2, 1.33 and 3 respectively, in compared to linear converters with same input-output combinations. In a 5–1.5V SCALDO regulator, using thin profile supercapacitors in the range of fractional farads to few farads, this translates to an approximate end to end efficiency of near 90%. However, there were concerns that this patented technique is merely a variation of well-known switched capacitor (charge pump) converters. This paper is aimed at providing a broad overview of the capability of SCALDO technique with generalized theory, indicating its capabilities and limitations, and comparing the practical performance with a typical switched capacitor converter of similar current capability

Влияние электромагнитных процессов в вентильных преобразователях на параметры качества электроэнергии в низковольтных электрических сетях

Приведены основные результаты теоретических исследований, полученные в отделе стабилизации параметров электромагнитной энергии ИЭД НАН Украины при выполнении в 2010 году научно-исследовательской работы по теме ”Сигма - Ш2” в соответствии с планом фундаментальных исследований в области повышения качества электроэнергии и обеспечения ЭМС в электрических сетях низкого напряжения с изменяющимися и нелинейными электроприемниками.Наведено основні результати теоретичних досліджень, отримані у відділі стабілізації параметрів електромагнітної енергії ІЕД НАН України при виконанні в 2010 році науково-дослідної роботи за темою ”Сигма - Ш2” відповідно до плану фундаментальних досліджень у сфері підвищення якості електроенергії та забезпечення ЕМС в електричних мережах низької напруги зі змінними і нелінійними електроприймачами.It is given basic results of theoretical investigations obtained in №2 department of Institute of Electrodynamics of National Academy of Seiencies of Ukraine, which are fulfilled in accordance with fundamental research work “Sigma - SH2”, in the field of high quality electrical energy supplying and electromagnetic compatibility providing in low voltage circuits with non-linear loads

Design, characterization and modeling of a tunneling break-down photodiode integrated in a standard 0.5ƒÝm CMOS technology

A low-voltage tunneling-breakdown photodiode has been designed, fabricated and characterized. Tests have been done to find dark-current, break-down voltage, turn on voltage, series and shunt resistance as well as spectral response. An average breakdown voltage of 1.1V states the device suitable for low-voltage circuits. After characterization, a model aimed for simulation in Spice was developed.Keywords: Photodetectors, Photodiodes, Solid state detectors

Bipolar-CMOS-DMOS Process-Based a Robust and High-Accuracy Low Drop-Out Regulator

A 40V BCD process high-accuracy and robust Low Drop-Out Regulator was proposed and tape-out in CSMC; the LDO was integrated in a LED Control and Driver SOC of outdoor applications. The proposed LDO converted the 12V~40V input power to 5V for the low voltage circuits inside the SOC. The robustness of LDO was important because the application condition of the SOC was bad. It was simulated in all process corner, -55℃~150℃ temperature and 12V~40V power voltage conditions. Simulation result shows that the LDO works robustly in conditions mentioned above. The default precision of LDO output voltage is ±2.75% max in all conditions, moreover, by utilizing a trim circuit in the feedback network, the precision can be improved to ±0.5% max after being trimmed by 3 bit digital trim signal Trim[3:1]. The total size of the proposed LDO is 135um*450um and the maximum current consumption is 284uA