Boost Half-Bridge DC-DC Converter with Reconfigurable Rectifier for Ultra-Wide Input Voltage Range Applications

DEFF Research Database (Denmark)

Vinnikov, Dmitri; Chub, Andrii; Liivik, Elizaveta

2018-01-01

This paper introduces a novel galvanically isolated boost half-bridge dc-dc converter intended for modern power electronic applications where ultra-wide input voltage regulation range is needed. A reconfigurable output rectifier stage performs a transition between the voltage doubler and the full......-bridge diode rectifiers and, by this means, extends the regulation range significantly. The converter features a low number of components and resonant soft switching of semiconductors, which result in high power conversion efficiency over a wide input voltage and load range. The paper presents the operating...

Fuzzy Load-Shedding Strategy Considering Photovoltaic Output Fluctuation Characteristics and Static Voltage Stability

Directory of Open Access Journals (Sweden)

Sheng Li

2018-03-01

Full Text Available Based on the equilibrium point equations of a classic three-node system integrated with a large-scale photovoltaic cell (PV power plant, the impact of PV output fluctuation on the saddle-node bifurcation (SNB was derived and analyzed. When PV runs in a unity power factor and the PV output active power Ppv is not too large (several hundred MW and below, the PV output fluctuation has little effect on the SNB point position and load margin index, so that the load margin index can be calculated online using the SNB point at Ppv = 0 pu. On the other hand, the local reactive power compensation in the load center can effectively raise the load bus voltage and make the voltage stability problem become more concealed; the traditional under-voltage load-shedding (UVLS strategy only carries out load shedding when the bus voltage amplitude is below the specified value and cannot effectively maintain the system static voltage stability in some occasions. In this paper, a fuzzy load-shedding strategy considering the impact of PV output fluctuations for the large-scale PV grid-connected system was designed, taking the load bus voltage amplitude and load margin index as fuzzy input variables, and the load-shedding command as a fuzzy output variable. Nine fuzzy IF-THEN rules were extracted for the fuzzy controller and the corresponding practical calculation method of load-shedding quantity was put forward. The simulation results of the classic three-node system and IEEE 14-bus system, both with a 100 MW PV power plant, verified the effectiveness of the fuzzy load-shedding controller whose input variable load margin index was calculated using the SNB point when the PV active power output was 0. The designed fuzzy load-shedding strategy can compensate for the defect—that the traditional UVLS strategy cannot effectively guarantee the system static voltage stability—and it can be widely used in power grids integrated with PV power plants whose scales are at a

Design and Implementation of a High-Voltage Generator with Output Voltage Control for Vehicle ER Shock-Absorber Applications

Directory of Open Access Journals (Sweden)

Chih-Lung Shen

2013-01-01

Full Text Available A self-oscillating high-voltage generator is proposed to supply voltage for a suspension system in order to control the damping force of an electrorheological (ER fluid shock absorber. By controlling the output voltage level of the generator, the damping force in the ER fluid shock absorber can be adjusted immediately. The shock absorber is part of the suspension system. The high-voltage generator drives a power transistor based on self-excited oscillation, which converts dc to ac. A high-frequency transformer with high turns ratio is used to increase the voltage. In addition, the system uses the car battery as dc power supply. By regulating the duty cycle of the main switch in the buck converter, the output voltage of the buck converter can be linearly adjusted so as to obtain a specific high voltage for ER. The driving system is self-excited; that is, no additional external driving circuit is required. Thus, it reduces cost and simplifies system structure. A prototype version of the actual product is studied to measure and evaluate the key waveforms. The feasibility of the proposed system is verified based on experimental results.

Capacitive divider for output voltage measurement of intense electron beam accelerator

International Nuclear Information System (INIS)

Ding Desheng; Yi Lingzhi; Yu Binxiong; Hong Zhiqiang; Liu Jinliang

2012-01-01

A kind of simple-mechanism, easy-disassembly self-integrating capacitive divider used for measuring diode output voltage of intense electron beam accelerator (IEBA) is developed. The structure of the capacitive divider is described, and the capacitance value of the capacitive divider is calculated by theoretical analysis and electromagnetic simulation. The dependence of measurement voltage on electrical parameters such as stray capacitance, earth capacitance of front resistance is obtained by PSpice simulation. Measured waveforms appear overshoot phenomenon when stray capacitance of front resistance is larger, and the wavefront will be affected when earth capacitance of front resistance is larger. The diode output voltage waveforms of intense electron beam accelerator, are measured by capacitive divider and calibrated by water resistance divider, which is accordance with that measured by a resistive divider, the division ratio is about 563007. The designed capacitive divider can be used to measure high-voltage pulse with 100 ns full width at half maximum. (authors)

The harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter.

OpenAIRE

ПАНЧЕНКО, В В

2015-01-01

The author investigates a rectifier unit constructed on the basis of cascade connection of the main non-controlled m-pulse rectifier and PWM voltage booster converter. The research presents the analysis of the harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter on completely controlled keys. The dependence of the relative harmonic amplitude on the commutation corner is defined. The estimation of a rectifier unit electromagnetic compatibility wit...

Universal Voltage Conveyor and its Novel Dual-Output Fully-Cascadable VM APF Application

Directory of Open Access Journals (Sweden)

Norbert Herencsar

2017-03-01

Full Text Available This letter presents a novel realization of a voltage-mode (VM first-order all-pass filter (APF with attractive features. The proposed circuit employs a single readily available six-terminal active device called as universal voltage conveyor (UVC and only grounded passive components, which predict its easy monolithic integration with desired circuit simplicity. The auxiliary voltage input (W and output (ZP, ZN terminals of the device fully ensure easy cascadability of VM APF, since the input and output terminal impedances are theoretically infinitely high and zero, respectively. Moreover, thanks to mutually inverse outputs of the UVC, the proposed filter simultaneously provides both inverting and non-inverting outputs from the same configuration. All of these features make the UVC a unique active device currently available in the literature. The behavior of the filter was experimentally measured using the readily available UVC-N1C 0520 chip, which was produced in cooperation with ON Semiconductor Czech Republic, Ltd.

Monitoring the consistency of the dynalyser output via digital display unit and calculated practical peak voltage

International Nuclear Information System (INIS)

Wan Hazlinda Ismail; Muhammad Jamal Mohd Isa; Abdul Aziz Mohd Ramli; Shahrul Azlan Azizan

2010-01-01

This study was carried out to ensure the adequacy and accuracy of the Dynalyser Digital Display unit for measuring the true kVp from the invasive kVp meter unit during calibration of non-invasive kVp meters. An invasive high voltage divider (dynalyser) coupled to the x-ray system measures the true kilo voltage supplied to the x-ray tube. The kVp output measured was displayed via its digital display unit while its waveform was acquired using a calibrated oscilloscope. The waveform was used to calculate the Practical Peak Voltage (PPV) using the International Standard method adapted from IEC 61676 and treated as the true kVp value. The kVp output was measured at 9 points ranging between 40 kV-120 kV with interval steps of 10 kV and monitored every day. The test result was evaluated for variation of output, intrinsic error and limit of variation in compliance with the IEC standard. Results showed that kVp output measured by the display unit everyday is consistent with variations of not more than ±0.45 kV, intrinsic error of not more than ±0.009 kV and limits of variation of less than 1% which comply with the IEC standard requirement. The kVp output via digital display unit has a total uncertainty of not more than 2.8 kV (k=2) while the PPV output via oscilloscope has total uncertainty of not more than 0.75 kV (k=2). As a conclusion, the dynalyser digital display unit complies with standard requirement and can be used to measure the true kVp output during the calibration of non-invasive kVp meters. (author)

A Reconfigurable Series Resonant DC-DC Converter for Wide-Input and Wide-Output Voltages

DEFF Research Database (Denmark)

Shen, Yanfeng; Wang, Huai; Qin, Zian

2017-01-01

This paper proposes a dual-bridge based LC series resonant dc-dc converter. The input inverter unit incorporates two bridge structures, i.e., a full-bridge inverter and a half-bridge inverter. For the output rectifier, it can be a full-bridge rectifier or an asymmetric half-bridge rectifier....... Different from the conventional resonant converter, a fixed-frequency PWM control is employed which makes the optimization of magnetic components easier. The primary-side switches can achieve ZVS and the secondary-side diodes turn off with ZCS. In addition, the root-mean-square (RMS) values...... of the transformer currents do not significantly vary with respect to the voltage variation. Therefore, this converter can maintain high efficiency over a wide voltage range. The topology and operating principle are firstly described. Then the dc voltage gain and the RMS current characteristics are detailed. Finally...

Non-linear Membrane Properties in Entorhinal Cortical Stellate Cells Reduce Modulation of Input-Output Responses by Voltage Fluctuations

Science.gov (United States)

Fernandez, Fernando R.; Malerba, Paola; White, John A.

2015-01-01

The presence of voltage fluctuations arising from synaptic activity is a critical component in models of gain control, neuronal output gating, and spike rate coding. The degree to which individual neuronal input-output functions are modulated by voltage fluctuations, however, is not well established across different cortical areas. Additionally, the extent and mechanisms of input-output modulation through fluctuations have been explored largely in simplified models of spike generation, and with limited consideration for the role of non-linear and voltage-dependent membrane properties. To address these issues, we studied fluctuation-based modulation of input-output responses in medial entorhinal cortical (MEC) stellate cells of rats, which express strong sub-threshold non-linear membrane properties. Using in vitro recordings, dynamic clamp and modeling, we show that the modulation of input-output responses by random voltage fluctuations in stellate cells is significantly limited. In stellate cells, a voltage-dependent increase in membrane resistance at sub-threshold voltages mediated by Na+ conductance activation limits the ability of fluctuations to elicit spikes. Similarly, in exponential leaky integrate-and-fire models using a shallow voltage-dependence for the exponential term that matches stellate cell membrane properties, a low degree of fluctuation-based modulation of input-output responses can be attained. These results demonstrate that fluctuation-based modulation of input-output responses is not a universal feature of neurons and can be significantly limited by subthreshold voltage-gated conductances. PMID:25909971

Consciousness can reduce the voltage of the output signal of solar cell

Science.gov (United States)

Cao, Dayong

2011-03-01

When the sun's light radiate on the solar cell, it can produce the output signal as the pho- tocurrent. We use the Data Acquisition Modules to record the voltage of the output signals. The v1 is voltage of the photocurrent of solar cell1; The v2 is the one of solar cell2. And these two solar cells stay side by side. When we record the voltages from the morning to the noon, the voltages will go up, and the v1 is bigger than the v2 during this time. But in other experi- menter, not only sun's light ratiade on two solar cells, but also consciousness act on two solar cells. Not only I can use consciousness to reduce the growth voltage of the output signals, but also can change the v1 to be littler than the v2. The experiment was conducted on Sep. 2010. When light of lamp radiate on two solar cells, I can reduce v1, at the same time, can augment v2. These experiments had been finished in Los Angeles, Oct. 26th. And the experiment show that the consciousness active function differ from the passive function of conditioned reflex (of Pavlov). There is the physical system of the mass, energy, space and time-MEST; There is the spirited system of the mind, consciousness, emotion and desire-MECD; the information system is the code system. We can use the consciousness change the electron-structure of solar cell by the interaction of the information.

The effect of voltage droop on the output of an electrostatic accelerator free electron laser

CERN Document Server

Wright, C C; Lucas, J; Stuart, R A

2000-01-01

Electrostatic accelerator FEL oscillators when operated with energy recovery offer the prospect of long pulse, single-mode operation with very narrow linewidth at high-power levels. However, special care with wiggler construction, electron beam steering, and collector design is necessary to reduce the fraction of the electron beam lost before depressed collection to a sufficiently small value to stop the output hopping from one longitudinal mode of the cavity to another due to the droop of the terminal accelerating voltage. We are investigating what minimum recovery fraction is required both experimentally and theoretically. We have constructed a pulsed microwave FEM oscillator having an accelerating voltage of 65 kV supplied by a source, which is a capacitor, charged by a low-current, high-voltage supply. By changing the capacitor value, it is easily possible to achieve a range of voltage droop rates. Furthermore, because the gain bandwidth of the FEM is small, only 1 or 2 longitudinal modes are capable of b...

The effect of voltage droop on the output of an electrostatic accelerator free electron laser

International Nuclear Information System (INIS)

Wright, C.C.; Al-Shamma'a, A.I.; Lucas, J.; Stuart, R.A.

2000-01-01

Electrostatic accelerator FEL oscillators when operated with energy recovery offer the prospect of long pulse, single-mode operation with very narrow linewidth at high-power levels. However, special care with wiggler construction, electron beam steering, and collector design is necessary to reduce the fraction of the electron beam lost before depressed collection to a sufficiently small value to stop the output hopping from one longitudinal mode of the cavity to another due to the droop of the terminal accelerating voltage. We are investigating what minimum recovery fraction is required both experimentally and theoretically. We have constructed a pulsed microwave FEM oscillator having an accelerating voltage of 65 kV supplied by a source, which is a capacitor, charged by a low-current, high-voltage supply. By changing the capacitor value, it is easily possible to achieve a range of voltage droop rates. Furthermore, because the gain bandwidth of the FEM is small, only 1 or 2 longitudinal modes are capable of being amplified at any voltage which eases the problem of analysing mode hopping behaviour. A simple model of mode switching is outlined

CAMAC system for data acquisition on output of digital panel meter for DC voltage measurement

International Nuclear Information System (INIS)

Noda, Nobuaki.

1979-03-01

An interface between the digital panel meter (DPM) for DC voltage measurement and the CAMAC system for T-2 experiment in JIPP (Japan Institute of Plasma Physics) was designed and produced. This panel meter is used for the purpose of monitoring the deflected electrode voltage of a 6 channel, neutral particle, energy analyzer (parallel plate electrodes, electro static type). The method of connecting the DPM to the CAMAC system is that of taking the gate pulses with the width proportional to the voltage to be measured out of the output of the DPM and counting the clock pulses. This system uses each one channel of output register, interrupting register, scaler and clock generator, and the binary digital data is obtained in the scaler, and sent to the main memory of the computer HITAC 10-2 through the CAMAC crate controller. At this time, the interface gives the output of the gate pulses with the width proportional to the DPM input voltage from the DPM BUSY output and PRINT COMMAND output, depending on the sampling pulses from the output register. The interface also gives the end pulse communicating the completion of the output of gate pulses to the interrupting register. The software is summarized in the flow chart of the program and in the program list used for the test on this data acquisition system. The features of this system are to be able to obtain the binary data directly, and to be capable of saving the number of transmission lines required for data transfer. (Wakatsuki, Y.)

PI and Fuzzy Control Strategies for High Voltage Output DC-DC Boost Power Converter - Hardware Implementation and Analysis

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Siano, Pierluigi

2016-01-01

This paper presents the control strategies by Proportional-Integral (P-I) and Fuzzy Logic (FL) for a DC-DC boost power converter for high output voltage configuration. Standard DC-DC converters are traditionally used for high voltage direct current (HVDC) power transmission systems. But, lack its...... converter with inbuilt voltage-lift technique and overcome the aforementioned deficiencies. Further, the control strategy is adapted based on proportional-integral (P-I) and fuzzy logic, closed-loop controller to regulate the outputs and ensure the performances. Complete hardware prototype of EHV converter...... performances in terms of efficiency, reduced transfer gain and increased cost with sensor units. Moreover, the internal self-parasitic components reduce the output voltage and efficiency of classical high voltage converters (HVC). This investigation focused on extra high-voltage (EHV) DC-DC boost power...

A utility piezoelectric energy harvester with low frequency and high-output voltage: Theoretical model, experimental verification and energy storage

Directory of Open Access Journals (Sweden)

Guangyi Zhang

2016-09-01

Full Text Available In this paper, a utility piezoelectric energy harvester with low frequency and high-output voltage is presented. Firstly, the harvester’s three theoretical models are presented, namely the static model, the quasi static model and the dynamic vibration model. By analyzing the influence of the mass ratio of the mass block to the beam on output characteristics of the harvester, we compare the quasi static model and the dynamic vibration model and then define their applicable ranges. Secondly, simulation and experiments are done to verify the models, using the harvester with PZT-5H piezoelectric material, which are proved to be consistent with each other. The experimental results show that the output open-circuit voltage and the output power can reach up to 86.36V and 27.5mW respectively. The experiments are conducted when this harvester system is excited by the first modal frequency (58.90Hz with the acceleration 10m/s2. In this low frequency vibration case, it is easy to capture the energy in the daily environment. In addition, LTC 3588-1 chip (Linear Technology Corporation is used as the medium energy circuit to transfer charges from the PZT-5H electrode to the 0.22F 5V super capacitor and ML621 rechargeable button battery. For this super-capacitor, it takes about 100min for the capacitor voltage to rise from 0V to 3.6V. For this button battery, it takes about 200min to increase the battery voltage from 2.5V to 3.48V.

The use of an improved technique to reduce the variability of output voltage in real-time Fibre Bragg Grating based monitoring system

Science.gov (United States)

Vorathin, E.; Hafizi, Z. M.; Che Ghani, S. A.; Lim, K. S.; Aizzuddin, A. M.

2017-10-01

Fibre Bragg Grating (FBG) sensors have been widely utilized in the structural health monitoring (SHM) of structures. However, one of the main challenges of FBGs is the existence of inconsistency in output voltage during wavelength intensity demodulation utilizing photodetector (PD) to convert the light signal into digital voltage readings. Thus, the designation of this experimental work is to develop a robust FBG real-time monitoring system with the benefit of MATLAB graphical user interface (GUI) and voltage normalization algorithm to scale down the voltage inconsistency. Low-cost edge filter interrogation system has been practiced in the experimentation and splitter optical component is make use to reduce the intensity of the high power light source that leads to the formation of noise due to unwanted reflected wavelengths. The results revealed that with the advancement of the proposed monitoring system, the sensitivity of the FBG has been increased from 2.4 mV/N to 3.8 mV/N across the range of 50 N. The redundancy in output voltage variation data points has been reduced from 26 data/minute to 17 data/minute. The accuracy of the FBG in detecting the load induced falls in the acceptable range of total average error which is 1.38 %.

Graphene-Based Linear Tandem Micro-Supercapacitors with Metal-Free Current Collectors and High-Voltage Output.

Science.gov (United States)

Shi, Xiaoyu; Wu, Zhong-Shuai; Qin, Jieqiong; Zheng, Shuanghao; Wang, Sen; Zhou, Feng; Sun, Chenglin; Bao, Xinhe

2017-11-01

Printable supercapacitors are regarded as a promising class of microscale power source, but are facing challenges derived from conventional sandwich-like geometry. Herein, the printable fabrication of new-type planar graphene-based linear tandem micro-supercapacitors (LTMSs) on diverse substrates with symmetric and asymmetric configuration, high-voltage output, tailored capacitance, and outstanding flexibility is demonstrated. The resulting graphene-based LTMSs consisting of 10 micro-supercapacitors (MSs) present efficient high-voltage output of 8.0 V, suggestive of superior uniformity of the entire integrated device. Meanwhile, LTMSs possess remarkable flexibility without obvious capacitance degradation under different bending states. Moreover, areal capacitance of LTMSs can be sufficiently modulated by incorporating polyaniline-based pseudocapacitive nanosheets into graphene electrodes, showing enhanced capacitance of 7.6 mF cm -2 . To further improve the voltage output and energy density, asymmetric LTMSs are fabricated through controlled printing of linear-patterned graphene as negative electrodes and MnO 2 nanosheets as positive electrodes. Notably, the asymmetric LTMSs from three serially connected MSs are easily extended to 5.4 V, triple voltage output of the single cell (1.8 V), suggestive of the versatile applicability of this technique. Therefore, this work offers numerous opportunities of graphene and analogous nanosheets for one-step scalable fabrication of flexible tandem energy storage devices integrating with printed electronics on same substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An improved design of virtual output impedance loop for droop-controlled parallel three-phase Voltage Source Inverters

DEFF Research Database (Denmark)

Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

2012-01-01

-sequence virtual resistance even in the case of feeding a balanced three-phase load. Furthermore, to adapt to the variety of unbalanced loads, a dynamically-tuned negative-sequence resistance loop is designed, such that a good compromise between the quality of inverter output voltage and the performance of load......The virtual output impedance loop is known as an effective way to enhance the load sharing stability and quality of droop-controlled parallel inverters. This paper proposes an improved design of virtual output impedance loop for parallel three-phase voltage source inverters. In the approach...... sharing can be obtained. Finally, laboratory test results of two parallel three-phase voltage source inverters are shown to confirm the validity of the proposed method....

Three-Input Single-Output Voltage-Mode Multifunction Filter with Electronic Controllability Based on Single Commercially Available IC

Directory of Open Access Journals (Sweden)

Supachai Klungtong

2017-01-01

Full Text Available This paper presents a second-order voltage-mode filter with three inputs and single-output voltage using single commercially available IC, one resistor, and two capacitors. The used commercially available IC, called LT1228, is manufactured by Linear Technology Corporation. The proposed filter is based on parallel RLC circuit. The filter provides five output filter responses, namely, band-pass (BP, band-reject (BR, low-pass (LP, high-pass (HP, and all-pass (AP functions. The selection of each filter response can be done without the requirement of active and passive component matching condition. Furthermore, the natural frequency and quality factor are electronically controlled. Besides, the nonideal case is also investigated. The output voltage node exhibits low impedance. The experimental results can validate the theoretical analyses.

Output pressure and harmonic characteristics of a CMUT as function of bias and excitation voltage

DEFF Research Database (Denmark)

Lei, Anders; Diederichsen, Søren Elmin; Hansen, Sebastian Molbech

2015-01-01

of the transmitted signal. The generation of intrinsic harmonics by the CMUT can be minimized by decreasing the excitation signal. This, however, leads to lower fundamental pressure which limits the desired generation of harmonics in the medium. This work examines the output pressure and harmonic characteristics...... of a CMUT as function of bias and excitation voltage. The harmonic to fundamental ratio of the surface pressures declines for decreasing excitation voltage and increasing bias voltage. The ratio, however, becomes unchanged for bias levels close to the pull-in voltage. The harmonic limitations of the CMUT...

Series asymmetric supercapacitors based on free-standing inner-connection electrodes for high energy density and high output voltage

Science.gov (United States)

Tao, Jiayou; Liu, Nishuang; Rao, Jiangyu; Ding, Longwei; Al Bahrani, Majid Raissan; Li, Luying; Su, Jun; Gao, Yihua

2014-11-01

Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high output voltage.Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high

Pulse-voltage fast generator

International Nuclear Information System (INIS)

Valeev, R.I.; Nikiforov, M.G.; Kharchenko, A.F.

1988-01-01

The design is described and the test results of a four-channel pulse-voltage generator with maximum output voltage 200 kV are presented. The measurement results of generator triggering time depending on the value and polarity of the triggering voltage pulse for different triggering circuits are presented. The tests have shown stable triggering of all four channels of the generator in the range up to 40 % from selfbreakdown voltage. The generator triggering delay in the given range is <25 ns, asynchronism in channel triggering is <±1 ns

Optimal Design of a High Efficiency LLC Resonant Converter with a Narrow Frequency Range for Voltage Regulation

Directory of Open Access Journals (Sweden)

Junhao Luo

2018-05-01

Full Text Available As a key factor in the design of a voltage-adjustable LLC resonant converter, frequency regulation range is very important to the optimization of magnetic components and efficiency improvement. This paper presents a novel optimal design method for LLC resonant converters, which can narrow the frequency variation range and ensure high efficiency under the premise of a required gain achievement. A simplified gain model was utilized to simplify the calculation and the expected efficiency was initially set as 96.5%. The restricted area of parameter optimization design can be obtained by taking the intersection of the gain requirement, the efficiency requirement, and three restrictions of ZVS (Zero Voltage Switch. The proposed method was verified by simulation and experiments of a 150 W prototype. The results show that the proposed method can achieve ZVS from full-load to no-load conditions and can reach 1.6 times the normalized voltage gain in the frequency variation range of 18 kHz with a peak efficiency of up to 96.3%. Moreover, the expected efficiency is adjustable, which means a converter with a higher efficiency can be designed. The proposed method can also be used for the design of large-power LLC resonant converters to obtain a wide output voltage range and higher efficiency.

Input-output rearrangement of isolated converters

DEFF Research Database (Denmark)

Madsen, Mickey Pierre; Kovacevic, Milovan; Mønster, Jakob Døllner

2015-01-01

This paper presents a new way of rearranging the input and output of isolated converters. The new arrangement posses several advantages, as increased voltage range, higher power handling capabilities, reduced voltage stress and improved efficiency, for applications where galvanic isolation...

Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

KAUST Repository

Useinov, Arthur; Mryasov, Oleg; Kosel, Jü rgen

2011-01-01

In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR

A comprehensive analysis and hardware implementation of control strategies for high output voltage DC-DC boost power converter

OpenAIRE

Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede; Wheeler, Patrick; Siano, Pierluigi; Hammami, Manel

2017-01-01

Classical DC-DC converters used in high voltage direct current (HVDC) power transmission systems, lack in terms of efficiency, reduced transfer gain and increased cost with sensor (voltage/current) numbers. Besides, the internal self-parasitic behavior of the power components reduces the output voltage and efficiency of classical HV converters. This paper deals with extra high-voltage (EHV) dc-dc boost converter by the application of voltage-lift technique to overcome the aforementioned defic...

Membrane voltage fluctuations reduce spike frequency adaptation and preserve output gain in CA1 pyramidal neurons in a high conductance state

Science.gov (United States)

Fernandez, Fernando R.; Broicher, Tilman; Truong, Alan; White, John A.

2011-01-01

Modulating the gain of the input-output function of neurons is critical for processing of stimuli and network dynamics. Previous gain control mechanisms have suggested that voltage fluctuations play a key role in determining neuronal gain in vivo. Here we show that, under increased membrane conductance, voltage fluctuations restore Na+ current and reduce spike frequency adaptation in rat hippocampal CA1 pyramidal neurons in vitro. As a consequence, membrane voltage fluctuations produce a leftward shift in the f-I relationship without a change in gain, relative to an increase in conductance alone. Furthermore, we show that these changes have important implications for the integration of inhibitory inputs. Due to the ability to restore Na+ current, hyperpolarizing membrane voltage fluctuations mediated by GABAA-like inputs can increase firing rate in a high conductance state. Finally, our data show that the effects on gain and synaptic integration are mediated by voltage fluctuations within a physiologically relevant range of frequencies (10–40 Hz). PMID:21389243

A Three-Level Quasi-Two-Stage Single-Phase PFC Converter with Flexible Output Voltage and Improved Conversion Efficiency

DEFF Research Database (Denmark)

Tang, Yi; Zhu, Dexuan; Jin, Chi

2015-01-01

voltages, and it will be very suitable for high-power applications where the output voltage can be either lower or higher than the peak ac input voltage, e.g., plug-in hybrid electric vehicle charging systems. Moreover, the involved dc/dc buck conversion stage may only need to process partial input power...

A Comprehensive Analysis and Hardware Implementation of Control Strategies for High Output Voltage DC-DC Boost Power Converter

Directory of Open Access Journals (Sweden)

Sanjeevikumar Padmanaban

2017-01-01

Full Text Available Classical DC-DC converters used in high voltage direct current (HVDC power transmission systems, lack in terms of efficiency, reduced transfer gain and increased cost with sensor (voltage/current numbers. Besides, the internal self-parasitic behavior of the power components reduces the output voltage and efficiency of classical HV converters. This paper deals with extra high-voltage (EHV dc-dc boost converter by the application of voltage-lift technique to overcome the aforementioned deficiencies. The control strategy is based on classical proportional-integral (P-I and fuzzy logic closed-loop controller to get high and stable output voltage. Complete hardware prototype of EHV is implemented and experimental tasks are carried out with digital signal processor (DSP TMS320F2812. The control algorithms P-I, fuzzy logic and the pulse-width modulation (PWM signals for N-channel MOSFET device are performed by the DSP. The experimental results provided show good conformity with developed hypothetical predictions. Additionally, the presented study confirms that the fuzzy logic controller provides better performance than classical P-I controller under different perturbation conditions.

Development of a New Cascade Voltage-Doubler for Voltage Multiplication

OpenAIRE

Toudeshki, Arash; Mariun, Norman; Hizam, Hashim; Abdul Wahab, Noor Izzri

2014-01-01

For more than eight decades, cascade voltage-doubler circuits are used as a method to produce DC output voltage higher than the input voltage. In this paper, the topological developments of cascade voltage-doublers are reviewed. A new circuit configuration for cascade voltage-doubler is presented. This circuit can produce a higher value of the DC output voltage and better output quality compared to the conventional cascade voltage-doubler circuits, with the same number of stages.

Characteristics of output voltage and current of integrated nanogenerators

KAUST Repository

Yang, Rusen

2009-01-01

Owing to the anisotropic property and small output signals of the piezoelectric nanogenerators (NGs) and the influence of the measurement system and environment, identification of the true signal generated by the NG is critical. We have developed three criteria: Schottky behavior test, switching-polarity tests, and linear superposition of current and voltage tests. The 11 tests can effectively rule out the system artifacts, whose sign does not change with the switching measurement polarity, and random signals, which might change signs but cannot consistently add up or cancel out under designed connection configurations. This study establishes the standards for designing and scale up of integrated nanogenerators. © 2009 American Institute of Physics.

Output Force Enhancement of Scratch Drive Actuator in Low-Voltage Region by Using Flexible Joint

Directory of Open Access Journals (Sweden)

Shawn CHEN

2010-04-01

Full Text Available Here a low-voltage scratch drive actuator (LVSDA is proposed by incorporating flexible joint into the conventional SDA to improve performance in low-voltage region. Experimental results show that, at the same total plate length of 80 mm and width of 65 mm, the proposed LVSDA can be actuated as low as 40 V, much lower than 80 V, the minimum required input voltage of the conventional SDA. From finite element analysis by CosmosWorks, yielding effect is found to be a critical factor. Before yielding, LVSDA can provide better performance than SDA at the same input voltage. However, the yielding stress in flexible joint would limit the achievable maximum output force in high-voltage region. By varying joint length, width, or location, LVSDA is shown to be operated in low-voltage region where the conventional SDA can not be operated, and can still provide comparable performance as SDA in high-voltage region.

New internal multi-range resistors for ac voltage calibration by using TVC

International Nuclear Information System (INIS)

Ali, Rasha S M

2015-01-01

Accurate calibration of ac voltages up to 1000 V by using thermal converters requires range resistors connected in series with the converter. The combination of a thermal converter and range resistor is known as the thermal voltage converter. In this paper, multi-range internal range resistors are designed and implemented in the National Institute for Standards (NIS), Egypt to cover the ac voltage ranges from 10 V to 750 V. The range resistor values are 2 kΩ, 10 kΩ, 20 kΩ, 40 kΩ, 100 kΩ, and 150 kΩ to cover the voltage ranges 10 V, 50 V, 100 V, 200 V, 500 V, and 750 V, respectively. The six range resistors are mounted in series with a single-junction thermo-element in the same box to provide a new thermal voltage converter. The required range resistor is selected by using a six-pin selector switch. Each resistor is connected to a selector pin. The new thermal voltage converter ranges are automatically calibrated against other standard thermal voltage converters at different frequencies by using a LabVIEW program to determine their ac–dc transfer difference at each range. The expanded uncertainties are estimated according to the GUM for all ranges at different frequencies. The performance of the new thermal voltage converter is also evaluated by comparing its ac–dc differences and its accuracy in measuring the ac voltage at different frequencies with a traditional thermal voltage converter. (paper)

Identifying individual n- and p-type ZnO nanowires by the output voltage sign of piezoelectric nanogenerator

KAUST Repository

Lin, S S

2009-08-18

Based on a comparative study between the piezoelectric outputs of n-type nanowires (NWs) and n-core/p-shell NWs along with the previous study (Lu et al 2009 Nano. Lett. 9 1223), we demonstrate a one-step technique for identifying the conductivity type of individual ZnO nanowires (NWs) based on the output of a piezoelectric nanogenerator without destroying the sample. A negative piezoelectric output voltage indicates an NW is n-type and it appears after the tip scans across the center of the NW, while a positive output voltage reveals p-type conductivity and it appears before the tip scans across the central line of the NW. This atomic force microscopy based technique is reliable for statistically mapping the majority carrier type in ZnO NWs arrays. The technique may also be applied to other wurtzite semiconductors, such as GaN, CdS and ZnS. © 2009 IOP Publishing Ltd.

Direct model-based predictive control scheme without cost function for voltage source inverters with reduced common-mode voltage

Science.gov (United States)

Kim, Jae-Chang; Moon, Sung-Ki; Kwak, Sangshin

2018-04-01

This paper presents a direct model-based predictive control scheme for voltage source inverters (VSIs) with reduced common-mode voltages (CMVs). The developed method directly finds optimal vectors without using repetitive calculation of a cost function. To adjust output currents with the CMVs in the range of -Vdc/6 to +Vdc/6, the developed method uses voltage vectors, as finite control resources, excluding zero voltage vectors which produce the CMVs in the VSI within ±Vdc/2. In a model-based predictive control (MPC), not using zero voltage vectors increases the output current ripples and the current errors. To alleviate these problems, the developed method uses two non-zero voltage vectors in one sampling step. In addition, the voltage vectors scheduled to be used are directly selected at every sampling step once the developed method calculates the future reference voltage vector, saving the efforts of repeatedly calculating the cost function. And the two non-zero voltage vectors are optimally allocated to make the output current approach the reference current as close as possible. Thus, low CMV, rapid current-following capability and sufficient output current ripple performance are attained by the developed method. The results of a simulation and an experiment verify the effectiveness of the developed method.

Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

Directory of Open Access Journals (Sweden)

Sreenivasappa Veeranna Bhupasandra

2010-01-01

Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

Complete low power controller for high voltage power systems

International Nuclear Information System (INIS)

Sumner, R.; Blanar, G.

1997-01-01

The MHV100 is a custom CMOS integrated circuit, developed for the AMS experiment. It provides complete control for a single channel high voltage (HV) generator and integrates all the required digital communications, D to A and A to D converters, the analog feedback loop and output drivers. This chip has been designed for use in both distributed high voltage systems or for low cost single channel high voltage systems. The output voltage and current range is determined by the external components

Electron emission of cathode holder of vacuum diode of an intense electron-beam accelerator and its effect on the output voltage

Directory of Open Access Journals (Sweden)

Xin-Bing Cheng

2011-04-01

Full Text Available The vacuum diode which is used to generate relativistic electron beams is one of the most important parts of a pulsed-power modulator. In this paper, the electron emission of cathode holder of a vacuum diode and its effect on the output voltage is investigated by experiments on an intense electron-beam accelerator with 180 ns full width at half maximum and 200–500 kV output voltage. First, the field emission is analyzed and the electric field of the vacuum chamber is calculated. Then, the flatness of the output voltage is discussed before and after adding an insulation plate when a water load is used. It is found that the electron emission at the edges of the cathode holder is the main reason to cause the change of the flatness. Last, a piece of polyester film is used as a target to further show the electron emission of the cathode holder. This analysis shows that decreasing the electron emission of the cathode holder in such a pulse power modulator could be a good way to improve the quality of the output voltage.

Transient analysis of the output short-circuit fault of high power and high voltage DC power supply

International Nuclear Information System (INIS)

Yang Zhigang; Zhang Jian; Huang Yiyun; Hao Xu; Sun Haozhang; Guo Fei

2014-01-01

The transient conditions of output short-circuit fault of high voltage DC power supply was introduced, and the energy of power supply injecting into klystron during the protection process of three-electrode gas switch were analyzed and calculated in detail when klystron load happening electrode arc faults. The results of calculation and simulation are consistent with the results of the experiment. When the output short-circuit fault of high voltage power supply occurs, switch can be shut off in the microsecond, and the short circuit current can be controlled in 200 A. It has verified the rapidity and reliability of the three-electrode gas switch protection, and it has engineering application value. (authors)

Enhanced piezoelectric output voltage and Ohmic behavior in Cr-doped ZnO nanorods

International Nuclear Information System (INIS)

Sinha, Nidhi; Ray, Geeta; Godara, Sanjay; Gupta, Manoj K.; Kumar, Binay

2014-01-01

Highlights: • Low cost highly crystalline Cr-doped ZnO nanorods were synthesized. • Enhancement in dielectric, piezoelectric and ferroelectric properties were observed. • A high output voltage was obtained in AFM. • Cr-doping resulted in enhanced conductivity and better Ohmic behavior in ZnO/Ag contact. - Abstract: Highly crystalline Cr-doped ZnO nanorods (NRs) were synthesized by solution technique. The size distribution was analyzed by high resolution tunneling electron microscope (HRTEM) and particle size analyzer. In atomic force microscope (AFM) studies, peak to peak 8 mV output voltage was obtained on the application of constant normal force of 25 nN. It showed high dielectric constant (980) with phase transition at 69 °C. Polarization vs. electric field (P–E) loops with remnant polarization (6.18 μC/cm 2 ) and coercive field (0.96 kV/cm) were obtained. In I–V studies, Cr-doping was found to reduce the rectifying behavior in the Ag/ZnO Schottky contact which is useful for field effect transistor (FET) and solar cell applications. With these excellent properties, Cr-doped ZnO NRs can be used in nanopiezoelectronics, charge storage and ferroelectric applications

Improving the output voltage waveform of an intense electron-beam accelerator based on helical type Blumlein pulse forming line

Directory of Open Access Journals (Sweden)

Xin-Bing Cheng

2010-07-01

Full Text Available The Blumlein pulse forming line (BPFL consisting of an inner coaxial pulse forming line (PFL and an outer coaxial PFL is widely used in the field of pulsed power, especially for intense electron-beam accelerators (IEBA. The output voltage waveform determines the quality and characteristics of the output beam current of the IEBA. Comparing with the conventional BPFL, an IEBA based on a helical type BPFL can increase the duration of the output voltage in the same geometrical volume. However, for the helical type BPFL, the voltage waveform on a matched load may be distorted which influences the electron-beam quality. In this paper, an IEBA based on helical type BPFL is studied theoretically. Based on telegrapher equations of the BPFL, a formula for the output voltage of IEBA is obtained when the transition section is taken into account, where the transition section is between the middle cylinder of BPFL and the load. From the theoretical analysis, it is found that the wave impedance and transit time of the transition section influence considerably the main pulse voltage waveform at the load, a step is formed in front of the main pulse, and a sharp spike is also formed at the end of the main pulse. In order to get a well-shaped square waveform at the load and to improve the electron-beam quality of such an accelerator, the wave impedance of the transition section should be equal to that of the inner PFL of helical type BPFL and the transit time of the transition section should be designed as short as possible. Experiments performed on an IEBA with the helical type BPFL show reasonable agreement with theoretical analysis.

Thought waves remotely affect the performance (output voltage) of photoelectric cells

Science.gov (United States)

Cao, Dayong; Cao, Daqing

2012-02-01

In our experiments, thought waves have been shown to be capable of changing (affecting) the output voltage of photovoltaic cells located from as far away as 1-3 meters. There are no wires between brain and photoelectric cell and so it is presumed only the thought waves act on the photoelectric cell. In continual rotations, the experiments tested different solar cells, measuring devices and lamps, and the experiments were done in different labs. The first experiment was conducted on Oct 2002. Tests are ongoing. Conclusions and assumptions include: 1) the slow thought wave has the energy of space-time as defined by C1.00007: The mass, energy, space and time systemic theory- MEST. Every process releases a field effect electrical vibration which be transmitted and focussed in particular paths; 2) the thought wave has the information of the order of tester; 3) the brain (with the physical system of MEST) and consciousness (with the spirit system of the mind, consciousness, emotion and desire-MECD) can produce the information (a part of them as the Genetic code); 4) through some algorithms such as ACO Ant Colony Optimization and EA Evolutionary Algorithm (or genetic algorithm) working in RAM, human can optimize the information. This Optimizational function is the intelligence; 5) In our experiments, not only can thought waves affect the voltage of the output photoelectric signals by its energy, but they can also selectively increase or decrease those photoelectric currents through remote consciousness interface and a conscious-brain information technology.

Dose estimate by personal music players based on weighted output voltage

DEFF Research Database (Denmark)

Hammershøi, Dorte; Ordoñez Pizarro, Rodrigo Eduardo; Christensen, Anders Tornvig

2015-01-01

The exposure by personal music players may in future be displayed to users, as described in the current draft of EN 50332-3. The suggested procedure includes a weighting of the electrical output voltages of the music player, and does not include the significance of the earphone sensitivity. It does...... not include the weighting principles necessary for sound sources close to the ears either, which constitutes an inverse head-related transfer function for the free- or diffuse field. The purpose of the present study is to assess the uncertainties in the dose estimate determined this way. Measurements for 20...

Quantitative Analysis Method of Output Loss due to Restriction for Grid-connected PV Systems

Science.gov (United States)

Ueda, Yuzuru; Oozeki, Takashi; Kurokawa, Kosuke; Itou, Takamitsu; Kitamura, Kiyoyuki; Miyamoto, Yusuke; Yokota, Masaharu; Sugihara, Hiroyuki

Voltage of power distribution line will be increased due to reverse power flow from grid-connected PV systems. In the case of high density grid connection, amount of voltage increasing will be higher than the stand-alone grid connection system. To prevent the over voltage of power distribution line, PV system's output will be restricted if the voltage of power distribution line is close to the upper limit of the control range. Because of this interaction, amount of output loss will be larger in high density case. This research developed a quantitative analysis method for PV systems output and losses to clarify the behavior of grid connected PV systems. All the measured data are classified into the loss factors using 1 minute average of 1 second data instead of typical 1 hour average. Operation point on the I-V curve is estimated to quantify the loss due to the output restriction using module temperature, array output voltage, array output current and solar irradiance. As a result, loss due to output restriction is successfully quantified and behavior of output restriction is clarified.

E-beam high voltage switching power supply

Science.gov (United States)

Shimer, Daniel W.; Lange, Arnold C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

E-beam high voltage switching power supply

International Nuclear Information System (INIS)

Shimer, D.W.; Lange, A.C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360 degree/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs

An optical fiber Bragg grating and piezoelectric ceramic voltage sensor

Science.gov (United States)

Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

2017-10-01

Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

An optical fiber Bragg grating and piezoelectric ceramic voltage sensor.

Science.gov (United States)

Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

2017-10-01

Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

Analysis of loss distribution of Conventional Boost, Z-source and Y-source Converters for wide power and voltage range

DEFF Research Database (Denmark)

Gadalla, Brwene Salah Abdelkarim; Schaltz, Erik; Siwakoti, Yam Prasad

2017-01-01

Boost converters are needed in many applications which require the output voltage to be higher than the input voltage. Recently, boost type converters have been applied for industrial applications, and hence it has become an interesting topic of research. Many researchers proposed different...... impedance source converters with their unique advantages as having a high voltage gain in a small range of duty cycle ratio. However, the thermal behaviour of the semiconductor devices and passive elements in the impedance source converter is an important issue from a reliability point of view and it has...... not been investigated yet. Therefore, this paper presents a comparison between the conventional boost, the Z-source, and the Y-source converters based on a thermal evaluation of the semiconductors. In addition, the three topologies are also compared with respect to their efficiency. In this study...

Fuel Cell/Electrochemical Cell Voltage Monitor

Science.gov (United States)

Vasquez, Arturo

2012-01-01

A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

Electron emission of cathode holder of vacuum diode of an intense electron-beam accelerator and its effect on the output voltage

OpenAIRE

Xin-Bing Cheng; Jin-Liang Liu; Hong-Bo Zhang; Zhi-Qiang Hong; Bao-Liang Qian

2011-01-01

The vacuum diode which is used to generate relativistic electron beams is one of the most important parts of a pulsed-power modulator. In this paper, the electron emission of cathode holder of a vacuum diode and its effect on the output voltage is investigated by experiments on an intense electron-beam accelerator with 180 ns full width at half maximum and 200–500 kV output voltage. First, the field emission is analyzed and the electric field of the vacuum chamber is calculated. Then, the fla...

Newton Output Blocking Force under Low-Voltage Stimulation for Carbon Nanotube-Electroactive Polymer Composite Artificial Muscles.

Science.gov (United States)

Chen, I-Wen Peter; Yang, Ming-Chia; Yang, Chia-Hui; Zhong, Dai-Xuan; Hsu, Ming-Chun; Chen, YiWen

2017-02-15

This is a study on the development of carbon nanotube-based composite actuators using a new ionic liquid-doped electroactive ionic polymer. For scalable production purposes, a simple hot-pressing method was used. Carbon nanotube/ionic liquid-Nafion/carbon nanotube composite films were fabricated that exhibited a large output blocking force and a stable cycling life with low alternating voltage stimuli in air. Of particular interest and importance, a blocking force of 1.5 N was achieved at an applied voltage of 6 V. Operational durability was confirmed by testing in air for over 30 000 cycles (or 43 h). The superior actuation performance of the carbon nanotube/ionic liquid-Nafion/carbon nanotube composite, coupled with easy manufacturability, low driving voltage, and reliable operation, promises great potential for artificial muscle and biomimetic applications.

An implantable neurostimulator with an integrated high-voltage inductive power-recovery frontend

International Nuclear Information System (INIS)

Wang Yuan; Zhang Xu; Liu Ming; Li Peng; Chen Hongda

2014-01-01

This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery frontend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full-wave rectifier (up to 100 V AC input), high-voltage series regulators (24/5 V outputs) and a linear regulator (1.8/3.3 V output) with bandgap voltage reference. With the high voltage output of the series regulator, the proposed neurostimulator could deliver a considerably large current in high electrode-tissue contact impedance. This neurostimulator has been fabricated in a CSMC 1 μm 5/40/700 V BCD process and the total silicon area including pads is 5.8 mm 2 . Preliminary tests are successful as the neurostimulator shows good stability under a 13.56 MHz AC supply. Compared to previously reported works, our design has advantages of a wide induced voltage range (26–100 V), high output voltage (up to 24 V) and high-level integration, which are suitable for implantable neurostimulators. (semiconductor integrated circuits)

Multifunction Voltage-Mode Filter Using Single Voltage Differencing Differential Difference Amplifier

Directory of Open Access Journals (Sweden)

Chaichana Amornchai

2017-01-01

Full Text Available In this paper, a voltage mode multifunction filter based on single voltage differencing differential difference amplifier (VDDDA is presented. The proposed filter with three input voltages and single output voltage is constructed with single VDDDA, two capacitors and two resistors. Its quality factor can be adjusted without affecting natural frequency. Also, the natural frequency can be electronically tuned via adjusting of bias current. The filter can offer five output responses, high-pas (HP, band-pass (BP, band-reject (BR, low-pass (LP and all-ass (AP functions in the same circuit topology. The output response can be selected by choosing the suitable input voltage without the component matching condition and the requirement of additional double gain voltage amplifier. PSpice simulation results to confirm an operation of the proposed filter correspond to the theory.

Spectrum analysis of a voltage source converter due to semiconductor voltage drops

DEFF Research Database (Denmark)

Rasmussen, Tonny Wederberg; Eltouki, Mustafa

2017-01-01

It is known that power electronic voltage source converters are non-ideal. This paper presents a state-of-the-art review on the effect of semiconductor voltage drop on the output voltage spectrum, using single-phase H-bridge two-level converter topology with natural sampled pulse width modulation....... The paper describes the analysis of output voltage spectrum, when the semiconductor voltage drop is added. The results of the analysis of the spectral contribution including and excluding semiconductor voltage drop reveal a good agreement between the theoretical results, simulations and laboratory...

Logarithmic circuit with wide dynamic range

Science.gov (United States)

Wiley, P. H.; Manus, E. A. (Inventor)

1978-01-01

A circuit deriving an output voltage that is proportional to the logarithm of a dc input voltage susceptible to wide variations in amplitude includes a constant current source which forward biases a diode so that the diode operates in the exponential portion of its voltage versus current characteristic, above its saturation current. The constant current source includes first and second, cascaded feedback, dc operational amplifiers connected in negative feedback circuit. An input terminal of the first amplifier is responsive to the input voltage. A circuit shunting the first amplifier output terminal includes a resistor in series with the diode. The voltage across the resistor is sensed at the input of the second dc operational feedback amplifier. The current flowing through the resistor is proportional to the input voltage over the wide range of variations in amplitude of the input voltage.

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

Science.gov (United States)

Shimer, Daniel W.; Lange, Arnold C.

1995-01-01

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

Science.gov (United States)

Shimer, D.W.; Lange, A.C.

1995-05-23

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

Robust optimization of the output voltage of nanogenerators by statistical design of experiments

KAUST Repository

Song, Jinhui

2010-09-01

Nanogenerators were first demonstrated by deflecting aligned ZnO nanowires using a conductive atomic force microscopy (AFM) tip. The output of a nanogenerator is affected by three parameters: tip normal force, tip scanning speed, and tip abrasion. In this work, systematic experimental studies have been carried out to examine the combined effects of these three parameters on the output, using statistical design of experiments. A statistical model has been built to analyze the data and predict the optimal parameter settings. For an AFM tip of cone angle 70° coated with Pt, and ZnO nanowires with a diameter of 50 nm and lengths of 600 nm to 1 μm, the optimized parameters for the nanogenerator were found to be a normal force of 137 nN and scanning speed of 40 μm/s, rather than the conventional settings of 120 nN for the normal force and 30 μm/s for the scanning speed. A nanogenerator with the optimized settings has three times the average output voltage of one with the conventional settings. © 2010 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Robust optimization of the output voltage of nanogenerators by statistical design of experiments

KAUST Repository

Song, Jinhui; Xie, Huizhi; Wu, Wenzhuo; Roshan Joseph, V.; Jeff Wu, C. F.; Wang, Zhong Lin

2010-01-01

Nanogenerators were first demonstrated by deflecting aligned ZnO nanowires using a conductive atomic force microscopy (AFM) tip. The output of a nanogenerator is affected by three parameters: tip normal force, tip scanning speed, and tip abrasion. In this work, systematic experimental studies have been carried out to examine the combined effects of these three parameters on the output, using statistical design of experiments. A statistical model has been built to analyze the data and predict the optimal parameter settings. For an AFM tip of cone angle 70° coated with Pt, and ZnO nanowires with a diameter of 50 nm and lengths of 600 nm to 1 μm, the optimized parameters for the nanogenerator were found to be a normal force of 137 nN and scanning speed of 40 μm/s, rather than the conventional settings of 120 nN for the normal force and 30 μm/s for the scanning speed. A nanogenerator with the optimized settings has three times the average output voltage of one with the conventional settings. © 2010 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

High voltage wide range marx generator design and construction

International Nuclear Information System (INIS)

Thompson, J.E.

1976-01-01

A wide range, long pulse, Marx generator has been designed and constructed for the purpose of exciting a thermionic electron gun utilized for quasi-cw gas laser medium ionization. The Marx generator has been specifically designed to operate over a voltage range variable from 100 kV to 200 kV into a resistive load of between 83 kΩ and open circuit. This wide operating range, both in voltage and load impedance, was obtained using interstage coupling capacitors to assure overvoltage and subsequent breakdown of the three element spark gap switches used. This paper will discuss the motivation and specific application for the Marx generator and will present the relevant design procedure with particular emphasis on the interstage coupling and triggering techniques employed. Experimental data regarding the measured Marx generator performance will also be presented

Design & Fabrication of a High-Voltage Photovoltaic Cell

Energy Technology Data Exchange (ETDEWEB)

Felder, Jennifer; /North Carolina State U. /SLAC

2012-09-05

Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.

High voltage pulse generator. [Patent application

Science.gov (United States)

Fasching, G.E.

1975-06-12

An improved high-voltage pulse generator is described which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of the first rectifier connected between the first and second capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. The output voltage can be readily increased by adding additional charging networks. The circuit allows the peak level of the output to be easily varied over a wide range by using a variable autotransformer in the charging circuit.

Highly efficient integrated rectifier and voltage boosting circuits for energy harvesting applications

Directory of Open Access Journals (Sweden)

D. Maurath

2008-05-01

Full Text Available This paper presents novel circuit concepts for integrated rectifiers and voltage converting interfaces for energy harvesting micro-generators. In the context of energy harvesting, usually only small voltages are supplied by vibration-driven generators. Therefore, rectification with minimum voltage losses and low reverse currents is an important issue. This is realized by novel integrated rectifiers which were fabricated and are presented in this article. Additionally, there is a crucial need for dynamic load adaptation as well as voltage up-conversion. A circuit concept is presented, which is able to obtain both requirements. This generator interface adapts its input impedance for an optimal energy transfer efficiency. Furthermore, this generator interface provides implicit voltage up-conversion, whereas the generator output energy is stored on a buffer, which is connected to the output of the voltage converting interface. As simulations express, this fully integrated converter is able to boost ac-voltages greater than |0.35 V| to an output dc-voltage of 2.0 V–2.5 V. Thereby, high harvesting efficiencies above 80% are possible within the entire operational range.

A transimpedance CMOS multichannel amplifier with a 50 Ω-wide output range buffer for high counting rate applications

International Nuclear Information System (INIS)

Haralabidis, N.; Loukas, D.; Misiakos, K.; Katsafouros, S.

1997-01-01

A fast transimpedance multichannel amplifier has been designed, fabricated in CMOS 1.2-microm technology and tested. Each channel consists of a current sensitive preamplifier followed by a voltage amplification stage and an on-chip buffer able to drive 50 Ω loads with an output range of ±800 mV. Measured peaking time at the output is 40 ns and the circuit recovers to baseline in 90 ns. This results in a counting capability of more than 10 7 hits/s. Signals of both polarities can be handled. The first two stages consume a total of 2 mW per channel and the 50 Ω buffer consumes another 17 mW. The equivalent noise charge (ENC) is 1,100 e - rms with a slope of 40e - /pF. The IC is intended for use in gas and solid-state detectors with high particle rate and extensive charge release as in high energy calorimetry

A Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

DEFF Research Database (Denmark)

Shen, Yanfeng; Wang, Huai; Al-Durra, Ahmed

2018-01-01

This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant dc-dc converters, and meanwhile achieves high efficiency...... losses. The operation principles and characteristics of the proposed converter are firstly analyzed in this paper. Then the analytical solutions for the voltage gain, soft-switching, and rms currents are derived, which facilitates the parameters design and optimization. Finally, the proposed topology...... and analysis are verified with experimental results obtained from a 1-kW converter prototype....

High voltage short plus generation based on avalanche circuit

International Nuclear Information System (INIS)

Hu Yuanfeng; Yu Xiaoqi

2006-01-01

Simulate the avalanche circuit in series with PSPICE module, design the high voltage short plus generation circuit by avalanche transistor in series for the sweep deflection circuit of streak camera. The output voltage ranges 1.2 KV into 50 ohm load. The rise time of the circuit is less than 3 ns. (authors)

Voltage balancing strategies for serial connection of microbial fuel cells

Science.gov (United States)

Khaled, Firas; Ondel, Olivier; Allard, Bruno; Buret, François

2015-07-01

The microbial fuel cell (MFC) converts electrochemically organic matter into electricity by means of metabolisms of bacteria. The MFC power output is limited by low voltage and low current characteristics in the range of microwatts or milliwatts per litre. In order to produce a sufficient voltage level (>1.5 V) and sufficient power to supply real applications such as autonomous sensors, it is necessary to either scale-up one single unit or to connect multiple units together. Many topologies of connection are possible as the serial association to improve the output voltage, or the parallel connection to improve the output current or the series/parallel connection to step-up both voltage and current. The association of MFCs in series is a solution to increase the voltage to an acceptable value and to mutualize the unit's output power. The serial association of a large number of MFCs presents several issues. The first one is the hydraulic coupling among MFCs when they share the same substrate. The second one is the dispersion between generators that lead to a non-optimal stack efficiency because the maximum power point (MPP) operation of all MFCs is not permitted. Voltage balancing is a solution to compensate non-uniformities towards MPP. This paper presents solutions to improve the efficiency of a stack of serially connected MFCs through a voltage-balancing circuit. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2014)", edited by Adel Razek

Systems and methods for switched-inductor integrated voltage regulators

Science.gov (United States)

Shepard, Kenneth L.; Sturcken, Noah Andrew

2017-12-12

Power controller includes an output terminal having an output voltage, at least one clock generator to generate a plurality of clock signals and a plurality of hardware phases. Each hardware phase is coupled to the at least one clock generator and the output terminal and includes a comparator. Each hardware phase is configured to receive a corresponding one of the plurality of clock signals and a reference voltage, combine the corresponding clock signal and the reference voltage to produce a reference input, generate a feedback voltage based on the output voltage, compare the reference input and the feedback voltage using the comparator and provide a comparator output to the output terminal, whereby the comparator output determines a duty cycle of the power controller. An integrated circuit including the power controller is also provided.

Optimum voltage of auxiliary systems for thermal and nuclear power plants

International Nuclear Information System (INIS)

Tokumitsu, Iwao; Segawa, Motomichi

1979-01-01

In the power plants in Japan, their unit power output has been greatly enhanced since the introduction of new powerful thermal power plants from 1950's to 1960's. In both thermal and nuclear power plants, 1,000 MW machines have been already in operation. The increase of unit power output results in the increase of in-plant load capacity. Of these the voltage adopted for in-plant low voltage systems is now mainly 440 V at load terminals, and the voltage for in-plant high voltage systems has been changing to 6 kV level via 3 kV and 4 kV levels. As plant capacity increases, the load of low voltage systems significantly increases, and it is required to raise the voltage of 400 V level. By the way, the low voltage in AC is specified to be not higher than 600 V. This makes the change within the above range comparatively easy. Considering these conditions, it is recommended to change the voltage for low voltage systems to 575 V at power source terminals and 550 V at load terminals. Some merits in constructing power systems and in economy by raising the voltage were examined. Though demerits are also found, they are only about 15% of total merits. The most advantageous point in raising the voltage is to be capable of increasing the supplying range to low voltage system loads. (Wakatsuki, Y.)

Efficient Wide Range Converters (EWiRaC): A new family of high efficient AC-DC Converters

DEFF Research Database (Denmark)

Petersen, Lars; Andersen, Michael Andreas E.

2006-01-01

The performance in terms of efficiency of the existing power supplies used for PFC is very dependent on the input voltage range. The boost converter is the most commonly used PFC converter because of its simplicity and high efficiency. But, the boost converter as well as other known converters...... suffers a major penalty in efficiency when used at the low end of the voltage range (90VAC) in a universal voltage range application (90-270VAC). This paper addresses this problem by suggesting a new family of converters that effectively reduces the apparent voltage range with a factor of 2 by changing...... the converter topology according to the input voltage. This new converter type has been named: efficient wide range converter (EWiRaC). The performance of the EWiRaC is experimental verified in a universal input range (90-270VAC) application with an output voltage of 185VDC capable of 500W output power. The EWi...

A Voltage Doubler Circuit to Extend the Soft-switching Range of Dual Active Bridge Converters

DEFF Research Database (Denmark)

Qin, Zian; Shen, Yanfeng; Wang, Huai

2017-01-01

A voltage doubler circuit is realized to extend the soft-switching range of Dual Active Bridge (DAB) converters. No extra hardware is added to the DAB to form this circuit, since it is composed of the dc blocking capacitor and the low side full bridge converter, which already exist in DAB....... With the voltage doubler, the DAB converter can achieve soft switching and high efficiency when the low side dc voltage is close to 2 pu (1 pu is the high side dc voltage divided by the transformer turn ratio), which can be realized only when the low side dc voltage is close to 1 pu by using the conventional phase...... shift modulation in DAB. Thus the soft switching range is extended. The soft switching boundary conditions are derived. A map to show the soft switching or hard switching in the full load and voltage range is obtained. The feasibility and effectiveness of the proposed method is finally verified...

Novel Voltage limiting concept for avalance breakdown protection

NARCIS (Netherlands)

Ruijs, L.C.H.; Bezooijen, van A.; Mahmoudi, R.; Roermund, van A.H.M.

2006-01-01

Destructive over-voltage breakdown of cellular phone power transistors is prevented by using a new voltage-limiting concept. The output voltage is detected by an avalanche-based detector, and limited by decreasing the output power when needed. The voltage detector contains a low voltage bipolar NPN

Computer controlled high voltage system

Energy Technology Data Exchange (ETDEWEB)

Kunov, B; Georgiev, G; Dimitrov, L [and others

1996-12-31

A multichannel computer controlled high-voltage power supply system is developed. The basic technical parameters of the system are: output voltage -100-3000 V, output current - 0-3 mA, maximum number of channels in one crate - 78. 3 refs.

A CMOS frontend chip for implantable neural recording with wide voltage supply range

International Nuclear Information System (INIS)

Liu Jialin; Zhang Xu; Hu Xiaohui; Li Peng; Liu Ming; Chen Hongda; Guo Yatao; Li Bin

2015-01-01

A design for a CMOS frontend integrated circuit (chip) for neural signal acquisition working at wide voltage supply range is presented in this paper. The chip consists of a preamplifier, a serial instrumental amplifier (IA) and a cyclic analog-to-digital converter (CADC). The capacitive-coupled and capacitive-feedback topology combined with MOS-bipolar pseudo-resistor element is adopted in the preamplifier to create a −3 dB upper cut-off frequency less than 1 Hz without using a ponderous discrete device. A dual-amplifier instrumental amplifier is used to provide a low output impedance interface for ADC as well as to boost the gain. The preamplifier and the serial instrumental amplifier together provide a midband gain of 45.8 dB and have an input-referred noise of 6.7 μV rms integrated from 1 Hz to 5 kHz. The ADC digitizes the amplified signal at 12-bits precision with a highest sampling rate of 130 kS/s. The measured effective number of bits (ENOB) of the ADC is 8.7 bits. The entire circuit draws 165 to 216 μA current from the supply voltage varied from 1.34 to 3.3 V. The prototype chip is fabricated in the 0.18-μm CMOS process and occupies an area of 1.23 mm 2 (including pads). In-vitro recording was successfully carried out by the proposed frontend chip. (paper)

High Voltage Charge Pump

KAUST Repository

Emira, Ahmed A.; Abdelghany, Mohamed A.; Elsayed, Mohannad Yomn; Elshurafa, Amro M; Salama, Khaled N.

2014-01-01

Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

High Voltage Charge Pump

KAUST Repository

Emira, Ahmed A.

2014-10-09

Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

Design of planar electron gun for UHF range, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L.M.

2015-01-01

Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

Cell voltage versus electrode potential range in aqueous supercapacitors

Science.gov (United States)

Dai, Zengxin; Peng, Chuang; Chae, Jung Hoon; Ng, Kok Chiang; Chen, George Z.

2015-01-01

Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the capacitive potential ranges and the capacitance ratio of the two electrodes. Beyond the maximum charging voltage, a supercapacitor may still operate, but at the expense of a reduced cycle life. In addition, it is shown that the supercapacitor performance is strongly affected by the initial and zero charge potentials of the electrodes. Further, the differences are highlighted and elaborated between freshly prepared, aged under open circuit conditions, and cycled electrodes of composites of conducting polymers and carbon nanotubes. The first voltammetric charging-discharging cycle has an electrode conditioning effect to change the electrodes from their initial potentials to the potential of zero voltage, and reduce the irreversibility. PMID:25897670

AC Voltage Control of DC/DC Converters Based on Modular Multilevel Converters in Multi-Terminal High-Voltage Direct Current Transmission Systems

Directory of Open Access Journals (Sweden)

Rui Li

2016-12-01

Full Text Available The AC voltage control of a DC/DC converter based on the modular multilevel converter (MMC is considered under normal operation and during a local DC fault. By actively setting the AC voltage according to the two DC voltages of the DC/DC converter, the modulation index can be near unity, and the DC voltage is effectively utilized to output higher AC voltage. This significantly decreases submodule (SM capacitance and conduction losses of the DC/DC converter, yielding reduced capital cost, volume, and higher efficiency. Additionally, the AC voltage is limited in the controllable range of both the MMCs in the DC/DC converter; thus, over-modulation and uncontrolled currents are actively avoided. The AC voltage control of the DC/DC converter during local DC faults, i.e., standby operation, is also proposed, where only the MMC connected on the faulty cable is blocked, while the other MMC remains operational with zero AC voltage output. Thus, the capacitor voltages can be regulated at the rated value and the decrease of the SM capacitor voltages after the blocking of the DC/DC converter is avoided. Moreover, the fault can still be isolated as quickly as the conventional approach, where both MMCs are blocked and the DC/DC converter is not exposed to the risk of overcurrent. The proposed AC voltage control strategy is assessed in a three-terminal high-voltage direct current (HVDC system incorporating a DC/DC converter, and the simulation results confirm its feasibility.

A Pseudo Fractional-N Clock Generator with 50% Duty Cycle Output

Science.gov (United States)

Yang, Wei-Bin; Lo, Yu-Lung; Chao, Ting-Sheng

A proposed pseudo fractional-N clock generator with 50% duty cycle output is presented by using the pseudo fractional-N controller for SoC chips and the dynamic frequency scaling applications. The different clock frequencies can be generated with the particular phase combinations of a four-stage voltage-controlled oscillator (VCO). It has been fabricated in a 0.13µm CMOS technology, and work with a supply voltage of 1.2V. According to measured results, the frequency range of the proposed pseudo fractional-N clock generator is from 71.4MHz to 1GHz and the peak-to-peak jitter is less than 5% of the output period. Duty cycle error rates of the output clock frequencies are from 0.8% to 2% and the measured power dissipation of the pseudo fractional-N controller is 146µW at 304MHz.

A Fixed-Frequency Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

DEFF Research Database (Denmark)

Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

2017-01-01

This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant DC-DC converters, and meanwhile achieves high efficiency...... and characteristics of the proposed converter are analyzed. Finally, a 1-kW converter prototype is built and the experimental results verify the theoretical analyses....

Complementary power output characteristics of electromagnetic generators and triboelectric generators.

Science.gov (United States)

Fan, Feng-Ru; Tang, Wei; Yao, Yan; Luo, Jianjun; Zhang, Chi; Wang, Zhong Lin

2014-04-04

Recently, a triboelectric generator (TEG) has been invented to convert mechanical energy into electricity by a conjunction of triboelectrification and electrostatic induction. Compared to the traditional electromagnetic generator (EMG) that produces a high output current but low voltage, the TEG has different output characteristics of low output current but high output voltage. In this paper, we present a comparative study regarding the fundamentals of TEGs and EMGs. The power output performances of the EMG and the TEG have a special complementary relationship, with the EMG being a voltage source and the TEG a current source. Utilizing a power transformed and managed (PTM) system, the current output of a TEG can reach as high as ∼3 mA, which can be coupled with the output signal of an EMG to enhance the output power. We also demonstrate a design to integrate a TEG and an EMG into a single device for simultaneously harvesting mechanical energy. In addition, the integrated NGs can independently output a high voltage and a high current to meet special needs.

Wide-range voltage modulation

International Nuclear Information System (INIS)

Rust, K.R.; Wilson, J.M.

1992-06-01

The Superconducting Super Collider's Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-μs wide pulse with a rise time of less than 1 μs, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented

High Output Piezo/Triboelectric Hybrid Generator

Science.gov (United States)

Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

2015-03-01

Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA.cm-2, and average power density of ~4.44 mW.cm-2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.

High Output Piezo/Triboelectric Hybrid Generator

Science.gov (United States)

Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

2015-01-01

Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA·cm−2, and average power density of ~4.44 mW·cm−2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

Comparison of x-ray output of inverter-type x-ray equipment

International Nuclear Information System (INIS)

Asano, Hiroshi; Miyake, Hiroyuki; Yamamoto, Keiichi

2000-01-01

The x-ray output of 54 inverter-type x-ray apparatuses used at 18 institutions was investigated. The reproducibility and linearity of x-ray output and variations among the x-ray equipment were evaluated using the same fluorescence meter. In addition, the x-ray apparatuses were re-measured using the same non-invasive instrument to check for variations in tube voltage, tube current, and irradiation time. The non-invasive instrument was calibrated by simultaneously obtaining measurements with an invasive instrument, employing the tube voltage and current used for the invasive instrument, and the difference was calculated. Reproducibility of x-ray output was satisfactory for all x-ray apparatuses. The coefficient of variation was 0.04 or less for irradiation times of 5 ms or longer. In 84.3% of all x-ray equipment, variation in the linearity of x-ray output was 15% or less for an irradiation time of 5 ms. However, for all the apparatuses, the figure was 50% when irradiation time was the shortest (1 to 3 ms). Variation in x-ray output increased as irradiation time decreased. Variation in x-ray output ranged between 1.8 and 2.5 compared with the maximum and minimum values, excluding those obtained at the shortest irradiation time. The relative standard deviation ranged from ±15.5% to ±21.0%. The largest variation in x-ray output was confirmed in regions irradiated for the shortest time, with smaller variations observed for longer irradiation times. The major factor responsible for variation in x-ray output in regions irradiated for 10 ms or longer, which is a relatively long irradiation time, was variation in tube current. Variation in tube current was slightly greater than 30% at maximum, with an average value of 7% compared with the preset tube current. Variations in x-ray output in regions irradiated for the shortest time were due to photographic effects related to the rise and fall times of the tube voltage waveform. Accordingly, in order to obtain constant x

A low-ripple chargepump circuit for high voltage applications

NARCIS (Netherlands)

Berkhout, M.; Berkhout, M.; van Steenwijk, G.; van Steenwijk, Gijs; van Tuijl, Adrianus Johannes Maria

1995-01-01

The subject of this paper is a fully integrated chargepump circuit with a very low output voltage ripple. At a supply voltage of 30V the chargepump can source 1mA at an output voltage of 40V. Two simple modifications to the classical chargepump circuit give a substantial reduction of the output

A novel method of methanol concentration control through feedback of the amplitudes of output voltage fluctuations for direct methanol fuel cells

International Nuclear Information System (INIS)

An, Myung-Gi; Mehmood, Asad; Hwang, Jinyeon; Ha, Heung Yong

2016-01-01

This study proposes a novel method for controlling the methanol concentration without using methanol sensors for DMFC (direct methanol fuel cell) systems that have a recycling methanol-feed loop. This method utilizes the amplitudes of output voltage fluctuations of DMFC as a feedback parameter to control the methanol concentration. The relationship between the methanol concentrations and the amplitudes of output voltage fluctuations is correlated under various operating conditions and, based on the experimental correlations, an algorithm to control the methanol concentration with no sensor is established. Feasibility tests of the algorithm have been conducted under various operating conditions including varying ambient temperature with a 200 W-class DMFC system. It is demonstrated that the sensor-less controller is able to control the methanol-feed concentration precisely and to run the DMFC systems more energy-efficiently as compared with other control systems. - Highlights: • A new sensor-less algorithm is proposed to control the methanol concentration without using a sensor. • The algorithm utilizes the voltage fluctuations of DMFC as a feedback parameter to control the methanol feed concentration. • A 200 W DMFC system is operated to evaluate the validity of the sensor-less algorithm. • The algorithm successfully controls the methanol feed concentration within a small error bound.

Study on the construction and its operating characteristics of Marx high voltage pulse generator

International Nuclear Information System (INIS)

Chung, W.K.; Yook, C.C.

1984-01-01

This study is to investigate the operating characteristics of a Marx high voltage pulse generator, which is designed and fabricated for the purpose of constructing a linear theta-pinch plasma generating facility. The Marx generator consists of a 2 kJ capacitor bank of maximum output voltage of 200kV, a set of main spark switch, a triggring system, and high voltage charging power supply. The experimental results show that the operating characteristics of the generator can be controlled through varying nitrogen pressure as a filling gas. The output pulse of the generator is achieved close to the estimated voltage with the rise time of 3*m seconds. The stability of the generator is also very satisfactory within operating range of main spark switch. (Author)

Differential-output B-dot and D-dot monitors for current and voltage measurements on a 20-MA, 3-MV pulsed-power accelerator

Directory of Open Access Journals (Sweden)

T. C. Wagoner

2008-10-01

Full Text Available We have developed a system of differential-output monitors that diagnose current and voltage in the vacuum section of a 20-MA 3-MV pulsed-power accelerator. The system includes 62 gauges: 3 current and 6 voltage monitors that are fielded on each of the accelerator’s 4 vacuum-insulator stacks, 6 current monitors on each of the accelerator’s 4 outer magnetically insulated transmission lines (MITLs, and 2 current monitors on the accelerator’s inner MITL. The inner-MITL monitors are located 6 cm from the axis of the load. Each of the stack and outer-MITL current monitors comprises two separate B-dot sensors, each of which consists of four 3-mm-diameter wire loops wound in series. The two sensors are separately located within adjacent cavities machined out of a single piece of copper. The high electrical conductivity of copper minimizes penetration of magnetic flux into the cavity walls, which minimizes changes in the sensitivity of the sensors on the 100-ns time scale of the accelerator’s power pulse. A model of flux penetration has been developed and is used to correct (to first order the B-dot signals for the penetration that does occur. The two sensors are designed to produce signals with opposite polarities; hence, each current monitor may be regarded as a single detector with differential outputs. Common-mode-noise rejection is achieved by combining these signals in a 50-Ω balun. The signal cables that connect the B-dot monitors to the balun are chosen to provide reasonable bandwidth and acceptable levels of Compton drive in the bremsstrahlung field of the accelerator. A single 50-Ω cable transmits the output signal of each balun to a double-wall screen room, where the signals are attenuated, digitized (0.5-ns/sample, numerically compensated for cable losses, and numerically integrated. By contrast, each inner-MITL current monitor contains only a single B-dot sensor. These monitors are fielded in opposite-polarity pairs. The two

Network feedback regulates motor output across a range of modulatory neuron activity.

Science.gov (United States)

Spencer, Robert M; Blitz, Dawn M

2016-06-01

Modulatory projection neurons alter network neuron synaptic and intrinsic properties to elicit multiple different outputs. Sensory and other inputs elicit a range of modulatory neuron activity that is further shaped by network feedback, yet little is known regarding how the impact of network feedback on modulatory neurons regulates network output across a physiological range of modulatory neuron activity. Identified network neurons, a fully described connectome, and a well-characterized, identified modulatory projection neuron enabled us to address this issue in the crab (Cancer borealis) stomatogastric nervous system. The modulatory neuron modulatory commissural neuron 1 (MCN1) activates and modulates two networks that generate rhythms via different cellular mechanisms and at distinct frequencies. MCN1 is activated at rates of 5-35 Hz in vivo and in vitro. Additionally, network feedback elicits MCN1 activity time-locked to motor activity. We asked how network activation, rhythm speed, and neuron activity levels are regulated by the presence or absence of network feedback across a physiological range of MCN1 activity rates. There were both similarities and differences in responses of the two networks to MCN1 activity. Many parameters in both networks were sensitive to network feedback effects on MCN1 activity. However, for most parameters, MCN1 activity rate did not determine the extent to which network output was altered by the addition of network feedback. These data demonstrate that the influence of network feedback on modulatory neuron activity is an important determinant of network output and feedback can be effective in shaping network output regardless of the extent of network modulation. Copyright © 2016 the American Physiological Society.

A low-voltage fully balanced CMFF transconductor with improved linearity

Science.gov (United States)

Calvo, B.; Celma, S.; Alegre, J. P.; Sanz, M. T.

2007-05-01

This paper presents a new low-voltage pseudo-differential continuous-time CMOS transconductor for wideband applications. The proposed cell is based on a feedforward cancellation of the input common-mode signal and keeps the input common mode voltage constant, while the transconductance is easily tunable through a continuous bias voltage. Linearity is preserved during the tuning process for a moderate range of transconductance values. Simulation results for a 0.35 μm CMOS design show a 1:2 G m tuning range with an almost constant bandwidth over 600 MHz. Total harmonic distortion figures are below -60 dB over the whole range at 10 MHz up to a 200 μA p-p differential output. The proposed cell consumes less than 1.2 mW from a single 2.0 V supply.

Method and apparatus for current-output peak detection

Science.gov (United States)

De Geronimo, Gianluigi

2017-01-24

A method and apparatus for a current-output peak detector. A current-output peak detector circuit is disclosed and works in two phases. The peak detector circuit includes switches to switch the peak detector circuit from the first phase to the second phase upon detection of the peak voltage of an input voltage signal. The peak detector generates a current output with a high degree of accuracy in the second phase.

Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

Directory of Open Access Journals (Sweden)

Bing-Yu Wang

2014-11-01

Full Text Available In this study, we develop a clamped–clamped beam-type piezoelectric vacuum pressure sensing element. The clamped–clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10−6 to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage.

MAGY: An innovative high voltage-low current power supply for gyrotron

International Nuclear Information System (INIS)

Siravo, Ugo; Alex, Juergen; Bader, Michael; Carpita, Mauro; Fasel, Damien; Gavin, Serge; Perez, Albert

2011-01-01

From the electrical point of view, the body and the anode of high power gyrotrons behave as capacitive loads. A highly dynamic power supply is, therefore, hard to achieve. The MAGY concept (Modulator for the Anode of a triode type GYrotron) embodies an innovative solution to manage the capacitive current ensuring a very low ripple on the output voltage. It consists of a series of independent, bi-directional and regulated DC sources. Compared to existing topologies, this solution requires a smaller number of power modules. It avoids internal high frequency modulation and simultaneously offers high resolution of the output voltage and a wide range of operating scenarios.

A CMOS frontend chip for implantable neural recording with wide voltage supply range

Science.gov (United States)

Jialin, Liu; Xu, Zhang; Xiaohui, Hu; Yatao, Guo; Peng, Li; Ming, Liu; Bin, Li; Hongda, Chen

2015-10-01

A design for a CMOS frontend integrated circuit (chip) for neural signal acquisition working at wide voltage supply range is presented in this paper. The chip consists of a preamplifier, a serial instrumental amplifier (IA) and a cyclic analog-to-digital converter (CADC). The capacitive-coupled and capacitive-feedback topology combined with MOS-bipolar pseudo-resistor element is adopted in the preamplifier to create a -3 dB upper cut-off frequency less than 1 Hz without using a ponderous discrete device. A dual-amplifier instrumental amplifier is used to provide a low output impedance interface for ADC as well as to boost the gain. The preamplifier and the serial instrumental amplifier together provide a midband gain of 45.8 dB and have an input-referred noise of 6.7 μVrms integrated from 1 Hz to 5 kHz. The ADC digitizes the amplified signal at 12-bits precision with a highest sampling rate of 130 kS/s. The measured effective number of bits (ENOB) of the ADC is 8.7 bits. The entire circuit draws 165 to 216 μA current from the supply voltage varied from 1.34 to 3.3 V. The prototype chip is fabricated in the 0.18-μm CMOS process and occupies an area of 1.23 mm2 (including pads). In-vitro recording was successfully carried out by the proposed frontend chip. Project supported by the National Natural Science Foundation of China (Nos. 61474107, 61372060, 61335010, 61275200, 61178051) and the Key Program of the Chinese Academy of Sciences (No. KJZD-EW-L11-01).

SoC-Based Output Voltage Control for BESS with a Lithium-Ion Battery in a Stand-Alone DC Microgrid

Directory of Open Access Journals (Sweden)

Seung-Yeong Yu

2016-11-01

Full Text Available This paper proposes a new DC output voltage control for a battery energy storage system (BESS with a lithium-ion battery based on the state of charge (SoC. The proposed control scheme was verified through computer simulations for a typical stand-alone DC microgrid, which consists of a BESS, photovoltaic (PV panel, engine generator (EG, and DC load. A scaled hardware prototype for a stand-alone DC microgrid was set up in the lab, in which the proposed control scheme was loaded in a DSP controller. The experimental results were compared with the simulation results for performance verification. The proposed control scheme provides relatively lower variation of the DC grid voltage than the conventional droop control.

A CMOS integrated voltage and power efficient AC/DC converter for energy harvesting applications

International Nuclear Information System (INIS)

Peters, Christian; Ortmanns, Maurits; Manoli, Yiannos; Spreemann, Dirk

2008-01-01

In this paper, a fully CMOS integrated active AC/DC converter for energy harvesting applications is presented. The rectifier is realized in a standard 0.35 µm CMOS process without special process options. It works as a full wave rectifier and can be separated into two stages—one passive and one active. The active part is powered from the storage capacitor and consumes about 600 nA at 2 V supply. The input voltage amplitude range is between 1.25 and 3.75 V, and the operating frequency range is from 1 Hz to as much as several 100 kHz. The series voltage drop over the rectifier is less than 20 mV. Measurements in combination with an electromagnetic harvester show a significant increase in the achievable output voltage and power compared to a common, discrete Schottky diode rectifier. The measured efficiency of the rectifier is over 95%. Measurements show a negligible temperature influence on the output voltage between −40 °C and +125 °C

An ultra-low power output capacitor-less low-dropout regulator with slew-rate-enhanced circuit

Science.gov (United States)

Cheng, Xin; Zhang, Yu; Xie, Guangjun; Yang, Yizhong; Zhang, Zhang

2018-03-01

An ultra-low power output-capacitorless low-dropout (LDO) regulator with a slew-rate-enhanced (SRE) circuit is introduced. The increased slew rate is achieved by sensing the transient output voltage of the LDO and then charging (or discharging) the gate capacitor quickly. In addition, a buffer with ultra-low output impedance is presented to improve line and load regulations. This design is fabricated by SMIC 0.18 μm CMOS technology. Experimental results show that, the proposed LDO regulator only consumes an ultra-low quiescent current of 1.2 μA. The output current range is from 10 μA to 200 mA and the corresponding variation of output voltage is less than 40 mV. Moreover, the measured line regulation and load regulation are 15.38 mV/V and 0.4 mV/mA respectively. Project supported by the National Natural Science Foundation of China (Nos. 61401137, 61404043, 61674049).

Light-voltage conversion apparatus

Energy Technology Data Exchange (ETDEWEB)

Fujioka, Yoshiki

1987-09-19

In a light-voltage conversion unit, when input signal is applied, the output signal to the control circuit has quick rise-up time and slow breaking time. In order to improve this, a short-circuit transistor is placed at the diode, and this transistor is forced ON, when an output signal to the control circuit is lowered down to a constant voltage, to short-circuit between the output terminals. This, however, has a demerit of high power consumption by a transistor. In this invention, by connecting a light-emitting element which gets ON at the first transition and a light-emitting element which gets ON at the last transition, placing a light receiving element in front of each light-emitting element, when an input signal is applied; thus a load is driven only with ON signal of each light-emitting element, eliminating the delay in the last transition. All of these give a quick responsive light-voltage conversion without unnecessary power consumption. (5 figs)

Studying the effect of over-modulation on the output voltage of three-phase single-stage grid-connected boost inverter

Directory of Open Access Journals (Sweden)

A. Abbas Elserougi

2013-09-01

Full Text Available Voltage boosting is very essential issue in renewable-energy fed applications. The classical two-stage power conversion process is typically used to interface the renewable energy sources to the grid. For better efficiency, single-stage inverters are recommended. In this paper, the performance of single-stage three-phase grid-connected boost inverter is investigated when its gain is extended by employing over-modulation technique. Using of over-modulation is compared with the employment of third order harmonic injection. The latter method can increase the inverter gain by 15% without distorting the inverter output voltage. The performance of extended gain grid-connected boost inverter is also tested during normal operation as well as in the presence of grid side disturbances. Simulation and experimental results are satisfactory.

Fiber-optic voltage measuring system

Science.gov (United States)

Ye, Miaoyuan; Nie, De-Xin; Li, Yan; Peng, Yu; Lin, Qi-Qing; Wang, Jing-Gang

1993-09-01

A new fibre optic voltage measuring system has been developed based on the electrooptic effect of bismuth germanium oxide (Bi4Ge3O12)crystal. It uses the LED as the light source. The light beam emitted from the light source is transmitted to the sensor through the optic fibre and the intensity of the output beam is changed by the applied voltage. This optic signal is transmitted to the PIN detector and converted to an electric signal which is processed by the electronic circuit and 8098 single chip microcomputer the output voltage signal obtained is directly proportional to the applied voltage. This paper describes the principle the configuration and the performance parameters of the system. Test results are evaluated and discussed.

A cascaded three-phase symmetrical multistage voltage multiplier

International Nuclear Information System (INIS)

Iqbal, Shahid; Singh, G K; Besar, R; Muhammad, G

2006-01-01

A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM

Enhanced Voltage Control of VSC-HVDC Connected Offshore Wind Farms Based on Model Predictive Control

DEFF Research Database (Denmark)

Guo, Yifei; Gao, Houlei; Wu, Qiuwei

2018-01-01

This paper proposes an enhanced voltage control strategy (EVCS) based on model predictive control (MPC) for voltage source converter based high voltage direct current (VSCHVDC) connected offshore wind farms (OWFs). In the proposed MPC based EVCS, all wind turbine generators (WTGs) as well...... as the wind farm side VSC are optimally coordinated to keep voltages within the feasible range and reduce system power losses. Considering the high ratio of the OWF collector system, the effects of active power outputs of WTGs on voltage control are also taken into consideration. The predictive model of VSC...

Dynamic range of low-voltage cascode current mirrors

DEFF Research Database (Denmark)

Bruun, Erik; Shah, Peter Jivan

1995-01-01

Low-voltage cascode current mirrors are reviewed with respect to the design limitations imposed if all transistors in the mirror are required to operate in the saturation region. It is found that both a lower limit and an upper limit exist for the cascode transistor bias voltage. Further, the use....... The proposed configuration has the advantage of simplicity combined with a complete elimination of the need for fixed bias voltages or bias currents in the current mirror. A disadvantage is that it requires a higher input voltage to the current mirror...

A study on stimulation of DC high voltage power of LCC series parallel resonant in projectile velocity measurement system

Science.gov (United States)

Lu, Dong-dong; Gu, Jin-liang; Luo, Hong-e.; Xia, Yan

2017-10-01

According to specific requirements of the X-ray machine system for measuring velocity of outfield projectile, a DC high voltage power supply system is designed for the high voltage or the smaller current. The system comprises: a series resonant circuit is selected as a full-bridge inverter circuit; a high-frequency zero-current soft switching of a high-voltage power supply is realized by PWM output by STM32; a nanocrystalline alloy transformer is chosen as a high-frequency booster transformer; and the related parameters of an LCC series-parallel resonant are determined according to the preset parameters of the transformer. The concrete method includes: a LCC series parallel resonant circuit and a voltage doubling circuit are stimulated by using MULTISM and MATLAB; selecting an optimal solution and an optimal parameter of all parts after stimulation analysis; and finally verifying the correctness of the parameter by stimulation of the whole system. Through stimulation analysis, the output voltage of the series-parallel resonant circuit gets to 10KV in 28s: then passing through the voltage doubling circuit, the output voltage gets to 120KV in one hour. According to the system, the wave range of the output voltage is so small as to provide the stable X-ray supply for the X-ray machine for measuring velocity of outfield projectile. It is fast in charging and high in efficiency.

Enhanced Buck–Boost Neutral-Point-Clamped Inverters With Simple Capacitive-Voltage Balancing

DEFF Research Database (Denmark)

Tan, Kuan Khoon; Gao, Feng; Loh, Poh Chiang

2010-01-01

introduced for extending the inverters’ variation range to include voltageboost operation, but they generally require the inclusion of large passive components or have not yet been optimized in terms of waveform quality. The balancing of their capacitive voltages using a simple technique has also not yet...... simultaneously, two new buck–boost NPC inverters with simple capacitive-voltage-balancing capability are proposed. Both inverters are demonstrated to exhibit a doubling of voltage gain, with one of them also shown to produce a better output waveform quality. Simulation and experimental results are provided...

Symmetric voltage-controlled variable resistance

Science.gov (United States)

Vanelli, J. C.

1978-01-01

Feedback network makes resistance of field-effect transistor (FET) same for current flowing in either direction. It combines control voltage with source and load voltages to give symmetric current/voltage characteristics. Since circuit produces same magnitude output voltage for current flowing in either direction, it introduces no offset in presense of altering polarity signals. It is therefore ideal for sensor and effector circuits in servocontrol systems.

Universal Voltage Conveyor and Current Conveyor in Fast Full-Wave Rectifier

Directory of Open Access Journals (Sweden)

Josef Burian

2012-12-01

Full Text Available This paper deals about the design of a fast voltage-mode full-wave rectifier, where universal voltage conveyor and second-generation current conveyor are used as active elements. Thanks to the active elements, the input and output impedance of the non-linear circuit is infinitely high respectively zero in theory. For the rectification only two diodes and three resistors are required as passive elements. The performance of the circuit is shown on experimental measurement results showing the dynamic range, time response, frequency dependent DC transient value and RMS error for different values of input voltage amplitudes.

Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator

DEFF Research Database (Denmark)

Tuan Vu, Cao; Wisland, Dag T.; Lande, Tor Sverre

A low-voltage, low-power, and wide-tuning-range VCO which converts an analog input voltage to phase information for a frequency ΔΣ modulator is proposed in this paper. The VCO is based on a differential ring oscillator, which is improved with modified symmetric load and a positive feedback...

A 600kV 15mA Cockcroft-Walton high-voltage power supply with high stability and low-ripple voltage

International Nuclear Information System (INIS)

Su Tongling; Zhang Yimin; Chen Shangwen; Liu Yantong; Lv Huiyi; Liu Jiangtao

2006-01-01

A Cockcroft-Walton high-voltage power supply with high stability and low-ripple voltage has been developed. This power supply has been operated in a ns pulse neutron generator. The maximum non-load voltage is 600kV while the working voltage and load current are 550kV and 15mA, respectively. The tested results indicate that when the power supply is operated at 300kV, 6.7mA and the input voltage varies +/-10%, the long-term stability of the output voltage is S=(0.300-1.006)x10 -3 . The ripple voltage is δU P-P =6.2V at 300kV, 6.8-8.3mA and the ratio of δU P-P to the output voltage V H is δU P-P /V H =2.1x10 -5

An efficient high-voltage power supply for a photomultiplier tube

NARCIS (Netherlands)

Ainutdinov, VM; Vonsovskii, NN; Kompaniets, KG; Kozyr, AI; Mikhailov, YV

2003-01-01

An adjustable power supply for a photomultiplier tube operating in the pulsed spectrometric mode with a wide range of linearity is described. The power consumed by the source is 50 mW. The output voltage is varied from 800 to 2000 V. The maximum ripple amplitude is 2.5 mV.

Fully on-chip switched capacitor NMOS low dropout voltage regulator

CERN Document Server

Camacho, D; Camacho, Daniel; Moreira, Paulo

2010-01-01

This paper presents a 1.5 V 50 mA low dropout voltage (LDO) regulator using an NMOS transistor as the output pass element. Continuous time,operation of the LDO is achieved using a new switched floating capacitor scheme that raises the gate voltage of the pass element. The regulator has a 0.2 V dropout at a 50 mA load and is stable for a wide load current range with loading capacitances up to 50 pF. The output variation when a full load step is applied is 300 mV and the recovery time is below 0.3 mu s. it is designed in a 0.13 mu m CMOS process with an area of 0.008 mm(2) and its operation does not require any external component.

Effects of range-wide variation in climate and isolation on floral traits and reproductive output of Clarkia pulchella.

Science.gov (United States)

Bontrager, Megan; Angert, Amy L

2016-01-01

Plant mating systems and geographic range limits are conceptually linked by shared underlying drivers, including landscape-level heterogeneity in climate and in species' abundance. Studies of how geography and climate interact to affect plant traits that influence mating system and population dynamics can lend insight to ecological and evolutionary processes shaping ranges. Here, we examined how spatiotemporal variation in climate affects reproductive output of a mixed-mating annual, Clarkia pulchella. We also tested the effects of population isolation and climate on mating-system-related floral traits across the range. We measured reproductive output and floral traits on herbarium specimens collected across the range of C. pulchella. We extracted climate data associated with specimens and derived a population isolation metric from a species distribution model. We then examined how predictors of reproductive output and floral traits vary among populations of increasing distance from the range center. Finally, we tested whether reproductive output and floral traits vary with increasing distance from the center of the range. Reproductive output decreased as summer precipitation decreased, and low precipitation may contribute to limiting the southern and western range edges of C. pulchella. High spring and summer temperatures are correlated with low herkogamy, but these climatic factors show contrasting spatial patterns in different quadrants of the range. Limiting factors differ among different parts of the range. Due to the partial decoupling of geography and environment, examining relationships between climate, reproductive output, and mating-system-related floral traits reveals spatial patterns that might be missed when focusing solely on geographic position. © 2016 Botanical Society of America.

Tuning range and output power optimization of an external-cavity GaN diode laser at 455 nm

DEFF Research Database (Denmark)

Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

2016-01-01

In this paper we discuss how different feedback gratings affect the tuning range and the output power of external feedback diode laser systems. A tunable high-power narrow-spectrum external-cavity diode laser system around 455 nm is investigated. The laser system is based on a high-power GaN diode...... laser in a Littrow external-cavity. Both a holographic diffraction grating and a ruled diffraction grating are used as feedback elements in the external cavity. The output power, spectral bandwidth, and tunable range of the external cavity diode laser system are measured and compared with the two...... gratings at different injected currents. When the holographic grating is used, the laser system can be tuned over a range of 1.4 nm with an output power around 530 mW. When the ruled grating is used, the laser system can be tuned over a range of 6.0 nm with an output power around 80 mW. The results can...

Improvement the Capacity of Cockcroft-Walton High Voltage Source from 300 kV/20 mA to 500 kV/20 mA for Accelerating Voltage of Electron Beam Machine

International Nuclear Information System (INIS)

Suprapto; Djasiman

2002-01-01

The improvement capacity of Cockcroft-Walton high voltage source from 300 kV/20 mA to 500 kV/mA has been carrying out. To improve the capacity of high voltage source was done by means of increasing the stage number of voltage multiplier from 11 to 18 and its output voltage measuring resistance. Each stage of voltage multiplier consists of 2 capacitors and 2 circuits of high voltage diode. This voltage multiplier is constructed using main components of high voltage capacitor and high voltage diode each of 0.22 μF/50 kV and UF 5408 respectively. To avoid stray discharge and corona it was provided with high voltage electrode and corona ring. The test result indicated that the output voltage obtained from 16 stages was 350 kV according to operating condition of 25 MΩ resistive load and first stage voltage of 28.5 kV with oscillator frequency of 24 Hz. That condition requires anode voltage and current of 5.5 kV and 2.5 A respectively. The no load test for 16 stages indicates 400 kV of output voltage and 28.5 kV first stage voltage. Efficiency of high voltage source was 48 % at 6.75 kW of output power. The expected test of 500 kV with 18 stages of voltage multiplier can not be carried out because of some restrictive of loading system. From the test result can be predicted that the output voltage of 500 kV with 18 stages of voltage multiplier requires 31.2 kV of first stage voltage. Then the expected high voltage source of Cockcroft-Walton is capable as accelerating voltage source for Electron Beam Machine with energy of 500 kV. (author)

Development of Amorphous/Microcrystalline Silicon Tandem Thin-Film Solar Modules with Low Output Voltage, High Energy Yield, Low Light-Induced Degradation, and High Damp-Heat Reliability

Directory of Open Access Journals (Sweden)

Chin-Yi Tsai

2014-01-01

Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film solar modules with low output voltage, high energy yield, low light-induced degradation, and high damp-heat reliability were successfully designed and developed. Several key technologies of passivation, transparent-conducting-oxide films, and cell and segment laser scribing were researched, developed, and introduced into the production line to enhance the performance of these low-voltage modules. A 900 kWp photovoltaic system with these low-voltage panels was installed and its performance ratio has been simulated and projected to be 92.1%, which is 20% more than the crystalline silicon and CdTe counterparts.

A high voltage gain quasi Z-source isolated DC/DC converter

DEFF Research Database (Denmark)

Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang

2014-01-01

A compact quasi-Z-source DC/DC converter is presented with high voltage gain, isolated output, and improved efficiency. The improvements in size and performance were achieved by using a square wave inverter with only two output switches driving an isolating transformer in push-pull mode, followed...... by a voltage doubling output rectifier. The converter is well-suited to applications requiring a high voltage gain, especially renewable energy sources such as photovoltaic and fuel-cell power supplies. To demonstrate the converter's performance a prototype designed to output 400 V at 500 W was constructed...

Development of an intelligent high-voltage direct-current power supply for nuclear detectors

International Nuclear Information System (INIS)

Zhao Xiuliang

1997-01-01

The operation and performances of a new type direct-current high-voltage power supply are described. The power supply with intelligent feature is controlled by a single-chip microcomputer (8031), and various kinds of output voltage can be preset. The output-voltage is monitored and regulated by the single-chip microcomputer and displayed by LED. The output voltage is stable when the load current is within the allowable limits

Characterization of a low-voltage electron beam

International Nuclear Information System (INIS)

Berejka, A.J.

2004-01-01

Growing interests in low-voltage electron beam (EB) processing in areas that may require regulatory compliance, such as the curing of inks and coatings for food packaging materials and in the surface disinfection of medicinal and food containers, lead to the characterization of a low-voltage EB by two methods: a widely used thin radiochromic film and a film strip made on a continuous basis with an alanine coating. Using a laboratory unit, beam currents and voltages were varied and then optical density and alanine/matrix ratios were, respectively, determined. No inferences as to 'dose' were made. The radiochromic film was found to be insensitive to slight changes at low beam currents and to show considerable divergence and a broadening in response as current was increased across a meaningful range at the three applied beam voltages of 80, 100 and 120 kV. The electron paramagnetic resonance (EPR) increase in response of the alanine coated film taken as a ratio to an internal reference material within the test instrument itself was shown to have a linear response with respect to beam current and no divergence as current increased. The use of an alanine coating of thickness greater than that of the extrapolated range of the electron penetration offers a method for the characterization of the output of such very low-voltage beams

47 CFR 17.54 - Rated lamp voltage.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Rated lamp voltage. 17.54 Section 17.54... voltage. To insure the necessary lumen output by obstruction lights, the rated voltage of incandescent lamps used shall correspond to be within 3 percent higher than the voltage across the lamp socket during...

Mechanisms of Gain Control by Voltage-Gated Channels in Intrinsically-Firing Neurons

Science.gov (United States)

Patel, Ameera X.; Burdakov, Denis

2015-01-01

Gain modulation is a key feature of neural information processing, but underlying mechanisms remain unclear. In single neurons, gain can be measured as the slope of the current-frequency (input-output) relationship over any given range of inputs. While much work has focused on the control of basal firing rates and spike rate adaptation, gain control has been relatively unstudied. Of the limited studies on gain control, some have examined the roles of synaptic noise and passive somatic currents, but the roles of voltage-gated channels present ubiquitously in neurons have been less explored. Here, we systematically examined the relationship between gain and voltage-gated ion channels in a conductance-based, tonically-active, model neuron. Changes in expression (conductance density) of voltage-gated channels increased (Ca2+ channel), reduced (K+ channels), or produced little effect (h-type channel) on gain. We found that the gain-controlling ability of channels increased exponentially with the steepness of their activation within the dynamic voltage window (voltage range associated with firing). For depolarization-activated channels, this produced a greater channel current per action potential at higher firing rates. This allowed these channels to modulate gain by contributing to firing preferentially at states of higher excitation. A finer analysis of the current-voltage relationship during tonic firing identified narrow voltage windows at which the gain-modulating channels exerted their effects. As a proof of concept, we show that h-type channels can be tuned to modulate gain by changing the steepness of their activation within the dynamic voltage window. These results show how the impact of an ion channel on gain can be predicted from the relationship between channel kinetics and the membrane potential during firing. This is potentially relevant to understanding input-output scaling in a wide class of neurons found throughout the brain and other nervous systems

Three-level boost converter with zero voltage transition

Directory of Open Access Journals (Sweden)

Kuo-Ing Hwu

2017-06-01

Full Text Available As compared with the traditional boost converter, the three-level boost converter possesses several advantages, such as lower switch voltage stresses and lower inductor current ripple. To improve the efficiency, this paper proposes a zero voltage transition (ZVT three-level boost converter. With the proposed ZVT circuit, the switches can achieve soft switching. Moreover, by using the voltage balance control, the output voltage can be equally across the output capacitors. In this study, the effectiveness of the proposed topology is verified by the experimental results based on the field-programmable gate array control.

Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

Directory of Open Access Journals (Sweden)

Ryunosuke Miyoshi

2016-01-01

Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

High-voltage transistor converter for pulsed x-ray sources

International Nuclear Information System (INIS)

Krasil'nikov, S.B.; Kristalinskii, A.L.; Lozovoi, L.N.; Markov, S.N.; Sindalovskii, E.I.

1986-01-01

A 24-V/12-kV converter for MIRA-2D and NORA pulsed x-ray sources is described. When the low-voltage supply varies within 20-26 V, the frequency stability of the x-ray pulses is higher by a factor of 3 ≅ 3 than when the PRIMA converter is used. For 14-24 V, the average output power of the converter is independent of the load impedance and increases linearly with an increase in supply voltage. The efficiency of the converter reaches 60%. The converter operates in the temperature range of -40 to +60 0 C

Technique for enhancing the power output of an electrostatic generator employing parametric resonance

Science.gov (United States)

Post, Richard F.

2016-02-23

A circuit-based technique enhances the power output of electrostatic generators employing an array of axially oriented rods or tubes or azimuthal corrugated metal surfaces for their electrodes. During generator operation, the peak voltage across the electrodes occurs at an azimuthal position that is intermediate between the position of minimum gap and maximum gap. If this position is also close to the azimuthal angle where the rate of change of capacity is a maximum, then the highest rf power output possible for a given maximum allowable voltage at the minimum gap can be attained. This rf power output is then coupled to the generator load through a coupling condenser that prevents suppression of the dc charging potential by conduction through the load. Optimized circuit values produce phase shifts in the rf output voltage that allow higher power output to occur at the same voltage limit at the minimum gap position.

GaN Nanowire Arrays for High-Output Nanogenerators

KAUST Repository

Huang, Chi-Te

2010-04-07

Three-fold symmetrically distributed GaN nanowire (NW) arrays have been epitaxially grown on GaN/sapphire substrates. The GaN NW possesses a triangular cross section enclosed by (0001), (2112), and (2112) planes, and the angle between the GaN NW and the substrate surface is ∼62°. The GaN NW arrays produce negative output voltage pulses when scanned by a conductive atomic force microscope in contact mode. The average of piezoelectric output voltage was about -20 mV, while 5-10% of the NWs had piezoelectric output voltages exceeding -(0.15-0.35) V. The GaN NW arrays are highly stable and highly tolerate to moisture in the atmosphere. The GaN NW arrays demonstrate an outstanding potential to be utilized for piezoelectric energy generation with a performance probably better than that of ZnO NWs. © 2010 American Chemical Society.

Voltage regulator for generator

Energy Technology Data Exchange (ETDEWEB)

Naoi, K

1989-01-17

It is an object of this invention to provide a voltage regulator for a generator charging a battery, wherein even if the ambient temperature at the voltage regulator rises abnormally high, possible thermal breakage of the semiconductor elements constituting the voltage regulator can be avoided. A feature of this invention is that the semiconductor elements can be protected from thermal breakage, even at an abnormal ambient temperature rise at the voltage regulator for the battery charging generator, by controlling a maximum conduction ratio of a power transistor in the voltage regulator in accordance with the temperature at the voltage regulator. This is achieved through a switching device connected in series to the field coil of the generator and adapted to be controlled in accordance with an output voltage of the generator and the ambient temperature at the voltage regulator. 6 figs.

Fast response double series resonant high-voltage DC-DC converter

International Nuclear Information System (INIS)

Lee, S S; Iqbal, S; Kamarol, M

2012-01-01

In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

Science.gov (United States)

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters.

Output Current Ripple Reduction Algorithms for Home Energy Storage Systems

Directory of Open Access Journals (Sweden)

Jin-Hyuk Park

2013-10-01

Full Text Available This paper proposes an output current ripple reduction algorithm using a proportional-integral (PI controller for an energy storage system (ESS. In single-phase systems, the DC/AC inverter has a second-order harmonic at twice the grid frequency of a DC-link voltage caused by pulsation of the DC-link voltage. The output current of a DC/DC converter has a ripple component because of the ripple of the DC-link voltage. The second-order harmonic adversely affects the battery lifetime. The proposed algorithm has an advantage of reducing the second-order harmonic of the output current in the variable frequency system. The proposed algorithm is verified from the PSIM simulation and experiment with the 3 kW ESS model.

Voltage control on TEG-inverter system with pulse width modulation

International Nuclear Information System (INIS)

Kimura, N.; Kinoshita, H.; Matsuura, K.

1984-01-01

An ocean thermoelectric generating system can be expected to supply cheap electric power in future. And it can be used as base power supply or isolated power source in developing areas. The authors propose to apply forced-commutation inverter to thermoelectric energy conversion system and construct an electric power station which can be operated without any other synchronous generator (S-G) and can control ac system as stable as S-G. This paper shows that inverters can control voltage constant, though within a range of 10% load change, by using pulse width modulation (PWM). It also describes the design of the voltage control system covering from 50% to 100% load with combination of PWM and output voltage tap changing of TEG

Circuitry for monitoring a high direct current voltage supply for an ionization chamber

International Nuclear Information System (INIS)

1981-01-01

An arrangement to measure the voltage of the supply and a switching means controlled by this is described. The voltage measurer consists of first and second signal coupling means, the input of the second (connected to the voltage supply) is connected in series with the output of the first. An ionization chamber with this circuitry may be used to monitor the radiation output of a particle accelerator more accurately. Faulty measurements of the dose output, caused by voltages in the earth circuit, are avoided. (U.K.)

Power-MOSFET Voltage Regulator

Science.gov (United States)

Miller, W. N.; Gray, O. E.

1982-01-01

Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

Design and characterization of a high-power ultrasound driver with ultralow-output impedance

Science.gov (United States)

Lewis, George K.; Olbricht, William L.

2009-11-01

We describe a pocket-sized ultrasound driver with an ultralow-output impedance amplifier circuit (less than 0.05 Ω) that can transfer more than 99% of the voltage from a power supply to the ultrasound transducer with minimal reflections. The device produces high-power acoustical energy waves while operating at lower voltages than conventional ultrasound driving systems because energy losses owing to mismatched impedance are minimized. The peak performance of the driver is measured experimentally with a PZT-4, 1.54 MHz, piezoelectric ceramic, and modeled using an adjusted Mason model over a range of transducer resonant frequencies. The ultrasound driver can deliver a 100 Vpp (peak to peak) square-wave signal across 0-8 MHz ultrasound transducers in 5 ms bursts through continuous wave operation, producing acoustic powers exceeding 130 W. Effects of frequency, output impedance of the driver, and input impedance of the transducer on the maximum acoustic output power of piezoelectric transducers are examined. The small size, high power, and efficiency of the ultrasound driver make this technology useful for research, medical, and industrial ultrasonic applications.

Characteristics of output voltage and current of integrated nanogenerators

KAUST Repository

Yang, Rusen; Qin, Yong; Li, Cheng; Dai, Liming; Wang, Zhong Lin

2009-01-01

three criteria: Schottky behavior test, switching-polarity tests, and linear superposition of current and voltage tests. The 11 tests can effectively rule out the system artifacts, whose sign does not change with the switching measurement polarity

The output characteristic of cantilever-like tactile sensor based on the inverse magnetostrictive effect

Directory of Open Access Journals (Sweden)

Lili Wan

2017-05-01

Full Text Available The output characteristic model of a magnetostrictive cantilever-like tactile sensor has been founded based on the inverse-magnetostrictive effect, the flexure mode, and the Jiles-Atherton model. The magnetostrictive sensor has been designed and an output voltage is analyzed under the conditions of bias magnetic field, contact pressure and deflection of cantilever beam. The experiment has been performed to determine the relation among the induced output voltage, bias magnetic field, and pressure. It is found that the peak of the induced output voltage increases with an increasing pressure under the bias magnetic field of 4.8kA/m. The experimental result agrees well with the theoretical one and it means that the model can describe the relation among the induced output voltage, bias magnetic field, and pressure. The sensor with a Galfenol sheet may hold potentials in sample characterization and deformation predication in artificial intelligence area.

PC-based control of a high-voltage injector

International Nuclear Information System (INIS)

Constantin, F.

1998-01-01

The stability of high voltage injectors is one of the major problems in any accelerator system. Most of the troubles encountered in the normal operation of an accelerator are connected with the ion source and associated high voltage platforms, regardless of the source or high voltage generator type. The quality of the ion beam injected in the accelerator strongly depends on the power supplies used in the injector and on the ability to control the non-electrical parameters (gas-flow, temperature, etc.). A wide used method in controlling is based on optical links between high-voltage platform and computer, the adjustments being more or less automated. Although the method mentioned above can be still useful in injector control, a different approach is presented in this work, i.e., the computer itself is placed inside the high-voltage terminal. Only one optical link is still necessary to connect this computer with an user-friendly host at ground potential. Requirements: - varying and monitoring the filament current; - gas flow control in the ion source; - reading the vacuum values; - current and voltage control for the anodic, magnet, extraction, suppression and lens' sources. Even in the high voltage terminal there are compartments with different voltages regardless the floating ground. In our injector the extraction voltage is applied on the top of the ion source including the filament and the anodic voltage. The extraction voltage is of maximum 30 kV. In this situation a second optical link is required to transfer the control for the anodic and magnet source power supply assuming the dedicated computer on the floating ground. One PC is placed inside the high voltage terminal and one PC outside the injector. The optical link (more precisely two optical wires) connects the serial ports. The inside computer is equipped with two multipurpose ADC/DAC and digital I/O card. They permit to read or output DC levels ranging between 0 to 10 volts or TTL signals. The filament

Modular high voltage power supply for chemical analysis

Science.gov (United States)

Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

2008-07-15

A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

A Comparison Study of Sinusoidal PWM and Space Vector PWM Techniques for Voltage Source Inverter

Directory of Open Access Journals (Sweden)

Ömer Türksoy

2017-06-01

Full Text Available In this paper, the methods used to control voltage source inverters which have been intensively investigated in recent years are compared. Although the most efficient result is obtained with the least number of switching elements in the inverter topologies, the method used in the switching is at least as effective as the topology. Besides, the selected switching method to control the inverter will play an effective role in suppressing harmonic components while producing the ideal output voltage. There are many derivatives of pulse width modulation techniques that are commonly used to control voltage source inverters. Some of widespread methods are sinusoidal pulse width modulation and space vector pulse width modulation techniques. These modulation techniques used for generating variable frequency and amplitude output voltage in voltage source inverters, have been simulated by using MATLAB/SIMULINK. And, the total harmonic distortions of the output voltages are compared. As a result of simulation studies, sinusoidal pulse width modulation has been found to have more total harmonic distortion in output voltages of voltage source inverters in the simulation. Space vector pulse width modulation has been shown to produce a more efficient output voltage with less total harmonic distortion.

A high PSRR Class-D audio amplifier IC based on a self-adjusting voltage reference

OpenAIRE

Huffenus , Alexandre; Pillonnet , Gaël; Abouchi , Nacer; Goutti , Frédéric; Rabary , Vincent; Cittadini , Robert

2010-01-01

International audience; In a wide range of applications, audio amplifiers require a large Power Supply Rejection Ratio (PSRR) that the current Class-D architecture cannot reach. This paper proposes a self-adjusting internal voltage reference scheme that sets the bias voltages of the amplifier without losing on output dynamics. This solution relaxes the constraints on gain and feedback resistors matching that were previously the limiting factor for the PSRR. Theory of operation, design and IC ...

Very low power, high voltage base for a Photo Multiplier Tube for the KM3NeT deep sea neutrino telescope

International Nuclear Information System (INIS)

Timmer, P; Heine, E; Peek, H

2010-01-01

The described system is developed in the framework of a deep-sea submerged Very Large Volume neutrino Telescope where photons are detected by a large number of Photo Multiplier Tubes. These PMTs are placed in optical modules (OM). A basic Cockcroft-Walton (CW) voltage multiplier circuit design is used to generate multiple voltages to drive the dynodes of the photomultiplier tube. To achieve a long lifetime and a high reliability the dissipation in the OM must be kept to the minimum. The design is also constrained by size restrictions, load current, voltage range, and the maximum allowable ripple in the output voltage. A surface mount PMT-base PCB prototype is designed and successfully tested. The system draws less than 1.5 mA of supply current at a voltage of 3.3 V with outputs up to -1400 Vdc cathode voltage, a factor 10 less than the commercially available state of the art.

Very low power, high voltage base for a Photo Multiplier Tube for the KM3NeT deep sea neutrino telescope

CERN Document Server

Timmer, P; Peek, H

2010-01-01

The described system is developed in the framework of a deep-sea submerged Very Large Volume neutrino Telescope where photons are detected by a large number of Photo Multiplier Tubes. These PMTs are placed in optical modules (OM). A basic Cockcroft-Walton (CW) voltage multiplier circuit design is used to generate multiple voltages to drive the dynodes of the photomultiplier tube. To achieve a long lifetime and a high reliability the dissipation in the OM must be kept to the minimum. The design is also constrained by size restrictions, load current, voltage range, and the maximum allowable ripple in the output voltage. A surface mount PMT-base PCB prototype is designed and successfully tested. The system draws less than 1.5 mA of supply current at a voltage of 3.3 V with outputs up to -1400 Vdc cathode voltage, a factor 10 less than the commercially available state of the art

Compact driver, notably for a light emitting diode, having an auxiliary output

NARCIS (Netherlands)

2015-01-01

The current invention relates to a driver(10,20) for driving at least one main load and one auxiliary load comprising: ä power converter(101) adapted to convert an input voltage(Vin) into at least one main output voltage provided through a main output(1011) for driving said main load, and at least

Computer simulation for the effect of target angle in diagnostic x-ray tube output and half-value layer

International Nuclear Information System (INIS)

Hayami, Akimune; Fuchihata, Hajime; Yamazaki, Takeshi; Mori, Yoshinobu; Ozeki, Syuji.

1980-01-01

The change of target angle of X-ray tube plays an important role in changing both the output and the quality of X-rays. A computer simulation was made to estimate the effect of target angle on the output and the quality (half-value layer: HVL) in the central ray using Storm's semiempirical formula. The data here presented are the values of output and HVL for the target angles of 10, 15, 20 and 30 degrees and for the total filtrations of 1, 2, 3 and 4 mm Al eq., at an increment of 10 kV steps of applied voltage between 50 and 150 kV. The output values and HVL's as a function of target angle, applied voltage and total filtration are shown for a full-wave rectified diagnostic X-ray generator. As a result, changes ranging from 17 to 76% in the output and 5 to 66% in the HVL were noted by varying the target angle from 10 to 30 degrees. Therefore, the target angle of X-ray tube should be clearly stated whenever the output and the quality (HVL) of X-ray generator are discussed. (author)

IGZO TFT-based circuit with tunable threshold voltage by laser annealing

Science.gov (United States)

Huang, Xiaoming; Yu, Guang; Wu, Chenfei

2017-11-01

In this work, a high-performance inverter based on amorphous indium-gallium-zinc oxide thin-film transistors (TFTs) has been fabricated, which consists of a driver TFT and a load TFT. The threshold voltage (Vth) of the load TFT can be tuned by applying an area-selective laser annealing. The transfer curve of the load TFT shows a parallel shift into the negative bias direction upon laser annealing. Based on x-ray photoelectron spectroscopy analyses, the negative Vth shift can be attributed to the increase of oxygen vacancy concentration within the device channel upon laser irradiation. Compared to the untreated inverter, the laser annealed inverter shows much improved switching characteristics, including a large output swing range which is close to full swing, as well as an enhanced output voltage gain. Furthermore, the dynamic performance of ring oscillator based on the laser-annealed inverter is improved.

Analysis of Input and Output Ripples of PWM AC Choppers

Directory of Open Access Journals (Sweden)

Pekik Argo Dahono

2008-11-01

Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.

50V All-PMOS Charge Pumps Using Low-Voltage Capacitors

KAUST Repository

Emira, Ahmed

2012-10-06

In this work, two high-voltage charge pumps are introduced. In order to minimize the area of the pumping capacitors, which dominates the overall area of the charge pump, high density capacitors have been utilized. Nonetheless, these high density capacitors suffer from low breakdown voltage which is not compatible with the targeted high voltage application. To circumvent the breakdown limitation, a special clocking scheme is used to limit the maximum voltage across any pumping capacitor. The two charge pump circuits were fabricated in a 0:6m CMOS technology with poly0-poly1 capacitors. The output voltage of the two charge pumps reached 42:8V and 51V while the voltage across any capacitor did not exceed the value of the input voltage. Compared to other designs reported in the literature, the proposed charge pump provides the highest output voltage which makes it more suitable for tuning MEMS devices.

50V All-PMOS Charge Pumps Using Low-Voltage Capacitors

KAUST Repository

Emira, Ahmed; AbdelGhany, M.; Elsayed, M.; Elshurafa, Amro M.; Sedky, S.; Salama, Khaled N.

2012-01-01

In this work, two high-voltage charge pumps are introduced. In order to minimize the area of the pumping capacitors, which dominates the overall area of the charge pump, high density capacitors have been utilized. Nonetheless, these high density capacitors suffer from low breakdown voltage which is not compatible with the targeted high voltage application. To circumvent the breakdown limitation, a special clocking scheme is used to limit the maximum voltage across any pumping capacitor. The two charge pump circuits were fabricated in a 0:6m CMOS technology with poly0-poly1 capacitors. The output voltage of the two charge pumps reached 42:8V and 51V while the voltage across any capacitor did not exceed the value of the input voltage. Compared to other designs reported in the literature, the proposed charge pump provides the highest output voltage which makes it more suitable for tuning MEMS devices.

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

Science.gov (United States)

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

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.

A digital output piezoelectric accelerometer using a Pb(Zr, Ti)O3 thin film array electrically connected in series

International Nuclear Information System (INIS)

Kobayashi, T; Okada, H; Maeda, R; Itoh, T; Masuda, T

2010-01-01

A digital output piezoelectric accelerometer is proposed to realize an ultra-low power consumption wireless sensor node. The accelerometer has patterned piezoelectric thin films (piezoelectric plates) electrically connected in series accompanied by CMOS switches at the end of some of the piezoelectric plates. The connected piezoelectric plates amplify the output voltage without the use of amplifiers. The CMOS switches turn on when the output voltage of the piezoelectric plates is higher than the CMOS threshold voltage. The piezoelectric accelerometer converts the acceleration into a number of on-state CMOS switches, which can be called the digital output. The proposed digital output piezoelectric accelerometer, using Pb(Zr, Ti)O 3 (PZT) thin films as the piezoelectric material, was fabricated through a microelectromechanical system (MEMS) microfabrication process. The output voltage was found to be amplified by the number of connected piezoelectric plates. The DC output voltage obtained by using an AC to DC conversion circuit is proportional to the number of connections. The results show the potential for realizing the proposed digital output piezoelectric accelerometer

Influence of X and gamma radiation and bias conditions on dropout voltage of voltage regulators serial transistors

International Nuclear Information System (INIS)

Vukic, V.; Osmokrovic, P.; Stankovic, S.; Kovacevic, M.

2005-01-01

Research topic presented in this paper is degradation of characteristics of low-dropout voltage regulator's serial transistor during exposure of device to the ionizing radiation. Voltage regulators were exposed to X and γ radiation in two modes: without bias conditions, and with bias conditions and load. Tested circuits are representatives of the first and the second generation of low-dropout voltage regulators, with lateral and vertical PNP serial transistor: LM2940 and L4940. Experimental results of output voltage and serial dropout voltage change in function of total ionizing dose, during the medium-dose-rate exposure, were presented. (author) [sr

High Voltage Gain Dual Active Bridge Converter with an Extended Operation Range for Renewable Energy Systems

DEFF Research Database (Denmark)

Zhang, Zhe; Tomas Manez, Kevin; Yudi, Xiao

2018-01-01

Bridge (P2DAB) converter, i.e. low-voltage (LV) side parallel and high-voltage (HV) side series, is proposed to achieve high voltage gain and low current stress over switching devices and transformer windings. Given the unmodified P2DAB power stage, by regulating the phase-shift angle between......Developing bidirectional dc-dc converters has become a critical research topic and gains more and more attention in recent years due to the extensive applications of smart grids with energy storages, hybrid and electrical vehicles and dc microgrids. In this paper, a Partial Parallel Dual Active...... the paralleled active bridges, the power equations and voltage gain are then modified, and therefore the operation range can be extended effectively. The operating principles of the proposed converter and its power characteristics under various operation modes are studied, and the design constraints...

Sliding-mode control of single input multiple output DC-DC converter

Science.gov (United States)

Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

2016-10-01

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

Combined resonant tank capacitance and pulse frequency modulation control for ZCS-SR inverter-fed high voltage DC power supply

International Nuclear Information System (INIS)

Lee, S S; Iqbal, S; Kamarol, M

2011-01-01

Conventional pulse frequency modulated (PFM) zero current switching (ZCS) series resonant (SR) inverter fed high voltage dc power supplies have nearly zero switching loss. However, they have limitations of poor controllability at light loads and large output voltage ripple at low switching frequencies. To address these problems, this paper proposes a combined resonant tank capacitance and pulse frequency modulation based control approach. For the realization of the proposed control approach, the tank circuit of the resonant inverter is made up of several resonant capacitors that are switched into or out of the tank circuit by electromechanical switches. The output voltage of the converter is regulated by digitally modulating the resonant tank capacitance and narrowly varying the switching frequency. The proposed control scheme has several features, namely a wide range of controllability even at light loads, less output voltage ripple, and less current stress on the inverter's power switches at light loads. Therefore, the proposed control approach alleviates most of the problems associated with conventional PFM. Experimental results obtained from a scaled down laboratory prototype are presented to verify the effectiveness of the proposed system.

A high-voltage equipment (high voltage supply, high voltage pulse generators, resonant charging inductance, synchro-instruments for gyrotron frequency measurements) for plasma applications

International Nuclear Information System (INIS)

Spassov, Velin

1996-01-01

This document reports my activities as visitor-professor at the Gyrotron Project - INPE Plasma Laboratory. The main objective of my activities was designing, construction and testing a suitable high-voltage pulse generator for plasma applications, and efforts were concentrated on the following points: Design of high-voltage resonant power supply with tunable output (0 - 50 kV) for line-type high voltage pulse generator; design of line-type pulse generator (4 microseconds pulse duration, 0 - 25 kV tunable voltage) for non linear loads such as a gyrotron and P III reactor; design of resonant charging inductance for resonant line-type pulse generator, and design of high resolution synchro instrument for gyrotron frequency measurement. (author)

Integration Testing of a Modular Discharge Supply for NASA's High Voltage Hall Accelerator Thruster

Science.gov (United States)

Pinero, Luis R.; Kamhawi, hani; Drummond, Geoff

2010-01-01

NASA s In-Space Propulsion Technology Program is developing a high performance Hall thruster that can fulfill the needs of future Discovery-class missions. The result of this effort is the High Voltage Hall Accelerator thruster that can operate over a power range from 0.3 to 3.5 kW and a specific impulse from 1,000 to 2,800 sec, and process 300 kg of xenon propellant. Simultaneously, a 4.0 kW discharge power supply comprised of two parallel modules was developed. These power modules use an innovative three-phase resonant topology that can efficiently supply full power to the thruster at an output voltage range of 200 to 700 V at an input voltage range of 80 to 160 V. Efficiencies as high as 95.9 percent were measured during an integration test with the NASA103M.XL thruster. The accuracy of the master/slave current sharing circuit and various thruster ignition techniques were evaluated.

Universal and inductorless DC/DC converter for multi-output power supplies in sensor and actuator networks

Science.gov (United States)

Saponara, Sergio; Ciarpi, Gabriele

2017-05-01

This work proposes a universal and inductorless DC/DC converter that can be used for a wide input range, from few V to 60 V, to regulate output voltages from 5 V down to 1 V in Sensor and Actuator Network nodes. The proposed converter has been developed within the Athenis3D European project. It is composed by a cascade of multiple switching capacitor stages, with a proper skip-mode control to implement both step-down and step-up converting ratios, thus regulating all input sources to a voltage of about 6 V. These switching stages are further cascaded with linear regulators, which can provide stable output voltages down to 1 V. The multi-output regulator has been realized as a single-chip in a low-cost 0.35 μm CMOS technology. It is available as a naked die or in a ceramic package. The only needed external components are surface mount capacitors, which can be integrated on top of the naked chip die, creating a 3D structure, using trench capacitors embedded in a passive interposing layer. This way the size of the power management unit is further minimized. An advantage of the proposed converter is that it isn't optimized for a particular input voltage, therefore it can be used with no constant input power, like power harvesting systems (e.g. solar cells, wind and water turbines) and very disturbed power supplies.

Design of a High Linearity Four-Quadrant Analog Multiplier in Wideband Frequency Range

Directory of Open Access Journals (Sweden)

Abdul kareem Mokif Obais

2017-05-01

Full Text Available In this paper, a voltage mode four quadrant analog multiplier in the wideband frequency rangeis designed using a wideband operational amplifier (OPAMP and squaring circuits. The wideband OPAMP is designed using 10 identical NMOS transistorsand operated with supply voltages of ±12V. Two NMOS transistors and two wideband OPAMP are utilized in the design of the proposed squaring circuit. All the NMOS transistors are based on 0.35µm NMOStechnology. The multiplier has input and output voltage ranges of ±10 V, high range of linearity from -10 V to +10 V, and cutoff frequency of about 5 GHz. The proposed multiplier is designed on PSpice in Orcad 16.6

A Novel Variable Stiffness Mechanism Capable of an Infinite Stiffness Range and Unlimited Decoupled Output Motion

Directory of Open Access Journals (Sweden)

Stefan Groothuis

2014-06-01

Full Text Available In this paper, a novel variable stiffness mechanism is presented, which is capable of achieving an output stiffness with infinite range and an unlimited output motion, i.e., the mechanism output is completely decoupled from the rotor motion, in the zero stiffness configuration. The mechanism makes use of leaf springs, which are engaged at different positions by means of two movable supports, to realize the variable output stiffness. The Euler–Bernoulli leaf spring model is derived and validated through experimental data. By shaping the leaf springs, it is shown that the stiffness characteristic of the mechanism can be changed to fulfill different application requirements. Alternative designs can achieve the same behavior with only one leaf spring and one movable support pin.

Development of a fast rise-time, high-voltage pulse generator

International Nuclear Information System (INIS)

Zhang Yanxia; Zhu Jie; Li Xianyou

2006-01-01

In order to test the attenuation of the system, a fast rise-time, high-voltage pulse generator is required for the fast pulse signal measurement. The paper presents the development of the generator. More emphasis is paid on the discussion of the difficulties occurring in the circuit debugging and their resolutions. The output rise-time of the generator is 700 ps, the amplitude is adjustable in the range of 0 to 500 V, the pulse-width is adjustable in the range of 4ns to 1μs. (authors)

Evaluation of indices for voltage stability monitoring using PMU measurements

Directory of Open Access Journals (Sweden)

Sindy Lorena Ramirez Perdomo

2014-09-01

Full Text Available Large disturbances such as voltage collapse and its consequences represent a large challenge to the operational safety of power systems. Therefore, it is important to have indicators of the presence of voltage stability problems in real time. Using phasor measure-ments of voltage and current that are presented in Phasor Measurement Units (PMU, indices for voltage stability monitoring can be calculated in real time. This paper presents some indices for voltage stability monitoring using PMU measurements. Evaluation of such indices on a simplified system was carried out, and the indices were classified according to their method of calculation. Finally, one of these indices was used with the New England 39-bus system under different operating scenarios, including load increments, line output and generator output, to check the indices’ behavior for voltage stability monitoring based on synchronized local measurements.

Improving the efficiency of microwave devices with a double output cavity

International Nuclear Information System (INIS)

Eppley, K.R.; Herrmannsfeldt, W.B.; Lee, T.G.

1986-05-01

Double output cavities have been used experimentally to increase the efficiency of high-power klystrons. We have used particle-in-cell simulations with the 2 + 1/2 dimensional code MASK to optimize the design of double output cavities for the lasertron and the 50 MW klystron under development at SLAC. We discuss design considerations for double output cavities (e.g., optimum choice of voltages and phases, efficiency, wall interception, breakdown). We describe how one calculates the cavity impedance matrix from the gap voltages and phases. Simulation results are compared to experience with the 150 MW klystron

Extending the Linear Modulation Range to the Full Base Speed Using a Single DC-Link Multilevel Inverter With Capacitor-Fed H-Bridges for IM Drives

DEFF Research Database (Denmark)

Rahul, Arun; Pramanick, Sumit; Kaarthik, R. Sudharshan

2017-01-01

In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage of the in......In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage...... of the inverter can be increased from 0.577 to 0.637Vdc without increasing the dc bus voltage and without exceeding the induction motor voltage rating. This new technique makes use of cascaded inverter pole voltage redundancy and property of the space vector structure for its operation. Using this, the induction...

Eliminating harmonics in line to line voltage using genetic algorithm using multilevel inverter

Energy Technology Data Exchange (ETDEWEB)

Gunasekaran, R. [Excel College of Engineering and Technology, Komarapalayam (India). Electrical and Electronics Engineering; Karthikeyan, C. [K.S. Rangasamy College of Engineering, Tamil Nadu (India). Electrical and Electronics Engineering

2017-04-15

In this project the total harmonic distortion (THD) minimization of the multilevel inverters output voltage is discussed. The approach in reducing harmonics contents in inverters output voltage is THD elimination. The switching angles are varied with the fundamental frequency so the output THD is minimized. In three phase applications, the line voltage harmonics are of the main concern from the load point of view. Using a genetic algorithm, a THD minimization process is directly applied to the line to line voltage of the inverter. Genetic (GA) algorithm allows the determination of the optimized parameters and consequently an optimal operating point of the circuit and a wide pass band with a unity gain is obtained.

High-voltage pulsed generator for dynamic fragmentation of rocks.

Science.gov (United States)

Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

2010-10-01

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

High-voltage pulsed generator for dynamic fragmentation of rocks

Science.gov (United States)

Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.

2010-10-01

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

A simple output voltage control scheme for single phase wavelet ...

African Journals Online (AJOL)

DR OKE

of the wavelet modulated (WM) scheme is that a single synthesis function, derived ... a single-phase H-bridge voltage-source (VS) inverter using MATLAB simulations. ... reconstruction process has been suggested to device a new class of ...

Determining the mode of high voltage breakdowns in vacuum devices

International Nuclear Information System (INIS)

Miller, H.C.; Furno, E.J.; Sturtz, J.P.

1980-01-01

Devices were constructed which were essentially vacuum diodes equipped with windows allowing observation of high voltage breakdowns. The waveform of the applied voltage was photographed, and the x-ray output was monitored to investigate electrical breakdown in these vacuum diodes. Results indicate that breakdowns may be divided into two types: (1) vacuum (interelectrode) breakdown - characterized by a diffuse moderately bright discharge, a relative slow and smooth voltage collapse, and a large burst of x-rays, and (2) surface (insulator) flashover - characterized by a bright discharge with a very bright filamentary core, a relatively fast and noisy voltage collapse and no x-ray burst. Useful information concerning the type of breakdown in a vacuum device can be obtained by monitoring the voltage (current) waveform and the x-ray output

Voltage Balancing Control of Diode-Clamped Multilevel Inverter

Directory of Open Access Journals (Sweden)

ŞCHIOP Adrian

2013-10-01

Full Text Available In this paper is developed a control scheme for mono-phase diode clamped inverter to achieve balancing voltages on inverter capacitors. First, it develops a control scheme without taking into account the need to balance voltage on two capacitors. It examines the effects on the output voltage inverter, and then it realizes two control schemes that will balance the voltages. The simulations of control schemes were performed in OrCAD Pspice.

Reducing Ripple In A Switching Voltage Regulator

Science.gov (United States)

Paulkovich, John; Rodriguez, G. Ernest

1994-01-01

Ripple voltage in output of switching voltage regulator reduced substantially by simple additional circuitry adding little to overall weight and size of regulator. Heretofore, additional filtering circuitry needed to obtain comparable reductions in ripple typically as large and heavy as original regulator. Current opposing ripple current injected into filter capacitor.

The design and development of low- and high-voltage ASICs for space-borne CCD cameras

Science.gov (United States)

Waltham, N.; Morrissey, Q.; Clapp, M.; Bell, S.; Jones, L.; Torbet, M.

2017-12-01

The CCD remains the pre-eminent visible and UV wavelength image sensor in space science, Earth and planetary remote sensing. However, the design of space-qualified CCD readout electronics is a significant challenge with requirements for low-volume, low-mass, low-power, high-reliability and tolerance to space radiation. Space-qualified components are frequently unavailable and up-screened commercial components seldom meet project or international space agency requirements. In this paper, we describe an alternative approach of designing and space-qualifying a series of low- and high-voltage mixed-signal application-specific integrated circuits (ASICs), the ongoing development of two low-voltage ASICs with successful flight heritage, and two new high-voltage designs. A challenging sub-system of any CCD camera is the video processing and digitisation electronics. We describe recent developments to improve performance and tolerance to radiation-induced single event latchup of a CCD video processing ASIC originally developed for NASA's Solar Terrestrial Relations Observatory and Solar Dynamics Observatory. We also describe a programme to develop two high-voltage ASICs to address the challenges presented with generating a CCD's bias voltages and drive clocks. A 0.35 μm, 50 V tolerant, CMOS process has been used to combine standard low-voltage 3.3 V transistors with high-voltage 50 V diffused MOSFET transistors that enable output buffers to drive CCD bias drains, gates and clock electrodes directly. We describe a CCD bias voltage generator ASIC that provides 24 independent and programmable 0-32 V outputs. Each channel incorporates a 10-bit digital-to-analogue converter, provides current drive of up to 20 mA into loads of 10 μF, and includes current-limiting and short-circuit protection. An on-chip telemetry system with a 12-bit analogue-to-digital converter enables the outputs and multiple off-chip camera voltages to be monitored. The ASIC can drive one or more CCDs and

Construction of an input sensitivity variable CAMAC module for measuring DC voltage

International Nuclear Information System (INIS)

Noda, Nobuaki.

1979-03-01

In on-line experimental data processing systems, the collection of DC voltage data is frequently required. In plasma confinement experiments, for example, the range of input voltage is very wide from over 1 kV applied to photomultiplier tubes to 10 mV full scale of the controller output for ionization vacuum gauges. A DC voltmeter CAMAC module with variable input range, convenient for plasma experiments and inexpensive, has been constructed for trial. The number of input channels is 16, and the input range is changeable in six steps from +-10 mV to +-200 V; these are all set by commands from a computer. The module is actually used for the on-line data processing system for JIPP T-2 experiment. The ideas behind its development, and the functions, features and usage of the module are described in this report. (J.P.N.)

Electronically Tunable Quadrature Sinusoidal Oscillator with Equal Output Amplitudes during Frequency Tuning Process

Directory of Open Access Journals (Sweden)

Den Satipar

2017-01-01

Full Text Available A new configuration of voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator employs two voltage differencing current conveyors (VDCCs, two resistors, and two grounded capacitors. In this design, the use of multiple/dual output terminal active building block is not required. The tuning of frequency of oscillation (FO can be done electronically by adjusting the bias current of active device without affecting condition of oscillation (CO. The electronic tuning can be done by controlling the bias current using a digital circuit. The amplitude of two sinusoidal outputs is equal when the frequency of oscillation is tuned. This makes the sinusoidal output voltages meet good total harmonic distortions (THD. Moreover, the proposed circuit can provide the sinusoidal output current with high impedance which is connected to external load or to another circuit without the use of buffer device. To confirm that the oscillator can generate the quadrature sinusoidal output signal, the experimental results using VDCC constructed from commercially available ICs are also included. The experimental results agree well with theoretical anticipation.

A 240W Monolithic Class-D Audio Amplifier Output Stage

OpenAIRE

Nyboe, Flemming; Kaya, Cetin; Risbo, Lars; Andreani, Pietro

2006-01-01

A single-channel class-D audio amplifier output stage outputs 240W undipped into 4Omega 0.1% open-loop THD+N allows using the device in a fully-digital audio signal path with no feedback. The output current capability is plusmn18A and the part is fabricated in a 0.4mum/1.8mum high-voltage BiCMOS process. Over-current sensing protects the output from short circuits.

Design of the all solid high-voltage power supply for a gyrotron body

Energy Technology Data Exchange (ETDEWEB)

Rao, Yihua [School of Mathematics and Physics, University of South China, Hengyang, 421001 (China); Chen, Wenguang, E-mail: 430000485393@usc.edu.cn [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Hu, Bo [School of Electrical Engineering, University of South China, Hengyang, 421001 (China); Rao, Jun; Huang, Mei; Kang, Zihua; Feng, Kun [Southwestern Institute of Physics, Chengdu, 610041 (China); Huang, Jiaqi [School of Electrical Engineering, University of South China, Hengyang, 421001 (China)

2017-04-15

Highlights: • Completed design of all solid-state high-voltage power supply for gyrotron body on HL-2M ECRH. • Consist of 58 PSM modules and one BUCK module, controlled by DSP system. • Fabricated full voltage 35 kV, 200 mA BPS and tested in dummy load. • The BPS can operate in three modes: single pulse mode, multi-pulse modulation mode and the six-level preset mode. - Abstract: Gyrotron plays an important role in the research of electron cyclotron resonance heating (ECRH) on Tokomak. The high-frequency switched power supply technology and pulse step modulation (PSM) technology are used in the development of the all solid high-voltage body power supply (BPS) for 1 MW/105 GHz Gyrotron on ECRH system. Firstly, the basic structure of the BPS and its control system are introduced. Secondly, the software control algorithm of voltage stabilization and modulate method are developed. Finally, the design is verified by the experiments. The experimental results of the single pulse mode, the multi-pulse modulation mode and the six-level preset mode, are shown. The output voltage of the power supply can reach 35 kV and the current at about 200 mA, which are adjustable in the full range. The maximum modulation frequency can reach 1 kHz and the front edge of the pulse can be adjust from 0 to 3 ms and the accuracy of the output voltage is less than 100 V. The results show that the control method is feasible and can be applied to other high power microwave sources.

Discussion - a high voltage DC generator

International Nuclear Information System (INIS)

Bhagwat, P.V.; Singh, Jagir; Hattangadi, V.A.

1993-01-01

One of the requirements for a high power ion source is a high voltage, high current DC generator. The high voltage, high current generator, DISCATRON, presently under development in our laboratory is a rotating disc type electrostatic generator similar in design to the one reported by A. Isoya et al. (1985). It is compact and rugged electrostatic DC generator based on the principle of induction charging by pellet chains used in the pelletron accelerator. It is, basically, a constant-current device with little stored energy, so that, in case of a breakdown, damage to the equipment connected to the output terminals is minimal. Since the present generator is only a proto-type, meant for a study of the practical difficulties that would be encountered in its manufacture, the output voltage and current specified has been kept quite modest viz., 300 kV at 500 μA, maximum. Some results of the preliminary tests carried out with this generator are described. (author). 4 figs

A compact, all solid-state LC high voltage generator.

Science.gov (United States)

Fan, Xuliang; Liu, Jinliang

2013-06-01

LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

HVDC Solution for Offshore Wind Park Comprising Turbines Equipped with Full-Range Converters

DEFF Research Database (Denmark)

Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj

2010-01-01

a voltage drop is created at the collection grid, the wind turbines go into fault-ride-through mode. The power output from each of the wind turbines is thus reduced to balance the system power. The detailed explanation of the strategy is presented in the paper. Matlab simulation model was prepared and some...... of a HVDC transmission system. The power system under study includes an offshore wind farm comprising turbines equipped with full range converters. The collection network is a local AC grid. Power transmission is done through HVDC system. The grid side VSC (voltage source converter) controls the DC voltage...

Design of power oscillator for 500 keV/20 mA Cockroft-Walton high voltage supply

International Nuclear Information System (INIS)

Djasiman; Sudjatmoko; Suprapto

1999-01-01

A design of power oscillator for Cockroft-Walton high voltage supply was carried out. This high voltage supply would be used as the acceleration voltage supply of an electron beam machine designed to have 500 keV/20 mA capacity. The power oscillator design consisted of output specification, circuit diagram, power supply and oscillator main components determinations. The power oscillator output wave power, voltage and frequency designed according to voltage multiplier input requirements. The design results showed that the circuit was class-c tickler oscillator having an output specification of 12.1 kW, 15 kV and 40 kHz sinus wave. The main component was a ITK 15-2 triode tube. (author)

New circuits high-voltage pulse generators with inductive-capacitive energy storage

International Nuclear Information System (INIS)

Gordeev, V.S.; Myskov, G.A.

2001-01-01

The paper describes new electric circuits of multi-cascade generators based on stepped lines. The distinction of the presented circuits consists in initial storage of energy in electric and magnetic fields simultaneously. The circuit of each generator,relations of impedances,values of initial current and charge voltages are selected in such a manner that the whole of initially stored energy is concentrated at the generator output as a result of transient wave processes. In ideal case the energy is transferred with 100% efficiency to the resistive load where a rectangular voltage pulse is formed, whose duration is equals to the double electrical length of the individual cascade. At the same time there is realized a several time increase of output voltage as compared to the charge voltage of the generator. The use of the circuits proposed makes it possible to ensure a several time increase (as compared to the selection of the number of cascades) of the generator energy storage, pulse current and output electric power

Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

Science.gov (United States)

Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

2011-01-01

A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

Programmable Input Mode Instrumentation Amplifier Using Multiple Output Current Conveyors

Directory of Open Access Journals (Sweden)

Pankiewicz Bogdan

2017-03-01

Full Text Available In this paper a programmable input mode instrumentation amplifier (IA utilising second generation, multiple output current conveyors and transmission gates is presented. Its main advantage is the ability to choose a voltage or current mode of inputs by setting the voltage of two configuration nodes. The presented IA is prepared as an integrated circuit block to be used alone or as a sub-block in a microcontroller or in a field programmable gate array (FPGA, which shall condition analogue signals to be next converted by an analogue-to-digital converter (ADC. IA is designed in AMS 0.35 µm CMOS technology and the power supply is 3.3 V; the power consumption is approximately 9.1 mW. A linear input range in the voltage mode reaches ± 1.68 V or ± 250 µA in current mode. A passband of the IA is above 11 MHz. The amplifier works in class A, so its current supply is almost constant and does not cause noise disturbing nearby working precision analogue circuits.

Voltage Stabilizer Based on SPWM technique Using Microcontroller

OpenAIRE

K. N. Tarchanidis; J. N. Lygouras; P. Botsaris

2013-01-01

This paper presents an application of the well known SPWM technique on a voltage stabilizer, using a microcontroller. The stabilizer is AC/DC/AC type. So, the system rectifies the input AC voltage to a suitable DC level and the intelligent control of an embedded microcontroller regulates the pulse width of the output voltage in order to produce through a filter a perfect sinusoidal AC voltage. The control program on the microcontroller has the ability to change the FET transistor ...

Construction of control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen

International Nuclear Information System (INIS)

Saminto; Eko Priyono; Sugeng Riyanto

2013-01-01

A control and instrumentation devices of high voltage power supply of double chamber plasma nitrogen have been made. This device consists of the software and hardware component. Hardware component consists of SCR phase angle controller LPC-50HDA type, T100MD1616+ PLC, high voltage transformer and voltage rectifier system. Software component used a LADDER program and TBasic serves to control of the high voltage output. The components in these devices have been tested in the double chamber plasma nitrogen. Its performance meet with the design criteria that can supply of plasma nitrogen operation voltage in the range 290 Vdc to 851 Vdc with glow discharge current 0.4 A to 1.4 A. In general it can be said that the control and instrumentation devices of high voltage power supply is ready for use at the double chamber plasma nitrogen device. (author)

An Integrated Inductor For Parallel Interleaved Three-Phase Voltage Source Converters

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

2016-01-01

Three phase Voltage Source Converters (VSCs) are often connected in parallel to realize high current output converter system. The harmonic quality of the resultant switched output voltage can be improved by interleaving the carrier signals of these parallel connected VSCs. As a result, the line...... of the state-of-the-art filtering solution. The performance of the integrated inductor is also verified by the experimental measurements....

A 240W Monolithic Class-D Audio Amplifier Output Stage

DEFF Research Database (Denmark)

Nyboe, Flemming; Kaya, Cetin; Risbo, Lars

2006-01-01

A single-channel class-D audio amplifier output stage outputs 240W undipped into 4Omega 0.1% open-loop THD+N allows using the device in a fully-digital audio signal path with no feedback. The output current capability is plusmn18A and the part is fabricated in a 0.4mum/1.8mum high-voltage Bi...

Low start-up voltage dc–dc converter with negative voltage control for thermoelectric energy harvesting

Directory of Open Access Journals (Sweden)

Pui-Sun Lei

2015-01-01

Full Text Available This Letter presents a low start-up voltage dc–dc converter for low-power thermoelectric systems which uses a native n-type MOS transistor as the start-up switch. The start-up voltage of the proposed converter is 300 mV and the converter does not need batteries to start up. The negative voltage control is proposed to reduce the leakage current caused by native n-type transistor and increase the efficiency. The proposed converter was designed using standard 0.18 µm CMOS process with chip size of 0.388 mm^2. The peak efficiency is 63% at load current of 1.5 mA. The proposed converter provides output voltage >1 V at maximum load current of 3.2 mA.

Harmonic elimination technique for a single-phase multilevel converter with unequal DC link voltage levels

DEFF Research Database (Denmark)

Ghasemi, N.; Zare, F.; Boora, A.A.

2012-01-01

Multilevel converters, because of the benefits they attract in generating high quality output voltage, are used in several applications. Various modulation and control techniques are introduced by several researchers to control the output voltage of the multilevel converters like space vector...... modulation and harmonic elimination (HE) methods. Multilevel converters may have a DC link with equal or unequal DC voltages. In this study a new HE technique based on the HE method is proposed for multilevel converters with unequal DC link voltage. The DC link voltage levels are considered as additional...

Cooperative Control with Virtual Selective Harmonic Capacitance for Harmonic Voltage Compensation in Islanded MicroGrids

DEFF Research Database (Denmark)

Micallef, A.; Apap, M.; Spitero-Stanies, C.

2012-01-01

This paper focuses on the islanded operation of microgrids. In this mode of operation, the microsources are required to cooperate autonomously to regulate the local grid voltage and frequency. Droop control is typically used to achieve this autonomous voltage and frequency regulation. Inverters...... having LCL output filters would cause voltage distortion to be present at the PCC of the local load when non-linear current is supplied to the load due to the voltage drop across the grid side inductor. Techniques to reduce the output voltage distortion typically consist of installing either passive...

Study on Control Scheme for the Inverters in Low Voltage Microgrid with Nonlinear Loads

Science.gov (United States)

Xu, Jiqiang; Lu, Wenzhou; Wu, Lei

2017-05-01

There are a lot of nonlinear loads in real low voltage microgrid system. It will cause serious output voltage and grid current harmonic distortions problems in island and grid-connected modes, respectively. To solve this problem, this paper proposes a droop control scheme with quasi-proportion and resonant (quasi-PR) controller based on αβ stationary reference frame to make microgrid smoothly switch between grid-connected and island modes without changing control method. Moreover, in island mode, not only stable output voltage and frequency, but also reduced output voltage harmonics with added nonlinear loads can be achieved; In grid-connected mode, not only constant power, but also reduced grid current harmonics can be achieved. Simulation results verify the effectiveness of the proposed control scheme.

A nanoscale piezoelectric transformer for low-voltage transistors.

Science.gov (United States)

Agarwal, Sapan; Yablonovitch, Eli

2014-11-12

A novel piezoelectric voltage transformer for low-voltage transistors is proposed. Placing a piezoelectric transformer on the gate of a field-effect transistor results in the piezoelectric transformer field-effect transistor that can switch at significantly lower voltages than a conventional transistor. The piezoelectric transformer operates by using one piezoelectric to squeeze another piezoelectric to generate a higher output voltage than the input voltage. Multiple piezoelectrics can be used to squeeze a single piezoelectric layer to generate an even higher voltage amplification. Coupled electrical and mechanical modeling in COMSOL predicts a 12.5× voltage amplification for a six-layer piezoelectric transformer. This would lead to more than a 150× reduction in the power needed for communications.

A Reduced Switch Voltage Stress Class E Power Amplifier Using Harmonic Control Network

OpenAIRE

Ali Reza Zirak; Sobhan Roshani

2016-01-01

In this paper, a harmonic control network (HCN) is presented to reduce the voltage stress (maximum MOSFET voltage) of the class E power amplifier (PA). Effects of the HCN on the amplifier specifications are investigated. The results show that the proposed HCN affects several specifications of the amplifier, such as drain voltage, switch current, output power capability (Cp factor), and drain impedance. The output power capability of the presented amplifier is also improved, compared with the ...

Fine Output Voltage Control Method considering Time-Delay of Digital Inverter System for X-ray Computed Tomography

Science.gov (United States)

Shibata, Junji; Kaneko, Kazuhide; Ohishi, Kiyoshi; Ando, Itaru; Ogawa, Mina; Takano, Hiroshi

This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.

An analog RF gap voltage regulation system for the Advanced Photon Source storage ring

International Nuclear Information System (INIS)

Horan, D.

1999-01-01

An analog rf gap voltage regulation system has been designed and built at Argonne National Laboratory to maintain constant total storage ring rf gap voltage, independent of beam loading and cavity tuning effects. The design uses feedback control of the klystron mod-anode voltage to vary the amount of rf power fed to the storage ring cavities. The system consists of two independent feedback loops, each regulating the combined rf gap voltages of eight storage ring cavities by varying the output power of either one or two rf stations, depending on the mode of operation. It provides full operator control and permissive logic to permit feedback control of the rf system output power only if proper conditions are met. The feedback system uses envelope-detected cavity field probe outputs as the feedback signal. Two different methods of combining the individual field probe signals were used to generate a relative DC level representing one-half of the total storage ring rf voltage, an envelope-detected vector sum of the field probe rf signals, and the DC sum of individual field probe envelope detector outputs. The merits of both methods are discussed. The klystron high-voltage power supply (HVPS) units are fitted with an analog interface for external control of the mod-anode voltage level, using a four-quadrant analog multiplier to modulate the HVPS mod-anode voltage regulator set-point in response to feedback system commands

Design of high voltage power supply of miniature X-ray tube based on resonant Royer

International Nuclear Information System (INIS)

Liu Xiyao; Zeng Guoqiang; Tan Chengjun; Luo Qun; Gong Chunhui; Huang Rui

2013-01-01

Background: In recent years, X rays are widely used in various fields. With the rapid development of national economy, the demand of high quality, high reliability, and high stability miniature X-ray tube has grown rapidly. As an important core component of miniature X-ray tube, high voltage power supply has attracted wide attention. Purpose: To match miniature, the high voltage power supply should be small, lightweight, good quality, etc. Based on the basic performance requirements of existing micro-X-ray tube high voltage power supply, this paper designs an output from 0 to -30 kV adjustable miniature X-ray tube voltage DC power supply. Compared to half-bridge and full-bridge switching-mode power supply, its driving circuit is simple. With working on the linear condition, it has no switching noise. Methods: The main circuit makes use of DC power supply to provide the energy. The resonant Royer circuit supplies sine wave which drives to the high frequency transformer's primary winding with resultant sine-like high voltage appearing across the secondary winding. Then, the voltage doubling rectifying circuit would achieve further boost. In the regulator circuit, a feedback control resonant transistor base current is adopted. In order to insulate air, a silicone rubber is used for high pressure part packaging, and the output voltage is measured by the dividing voltage below -5 kV. Results: The stability of circuit is better than 0.2%/6 h and the percent of the output ripple voltage is less than 0.3%. Keeping the output voltage constant, the output current can reach 57 μA by changing the size of load resistor. This high voltage power supply based on resonant Royer can meet the requirement of miniature X-ray tube. Conclusions: The circuit can satisfy low noise, low ripple, low power and high voltage regulator power supply design. However, its efficiency is not high enough because of the linear condition. In the next design, to further reduce power consumption, we

Scintillator-CCD camera system light output response to dosimetry parameters for proton beam range measurement

Energy Technology Data Exchange (ETDEWEB)

Daftari, Inder K., E-mail: idaftari@radonc.ucsf.edu [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States); Castaneda, Carlos M.; Essert, Timothy [Crocker Nuclear Laboratory,1 Shields Avenue, University of California-Davis, Davis, CA 95616 (United States); Phillips, Theodore L.; Mishra, Kavita K. [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States)

2012-09-11

The purpose of this study is to investigate the luminescence light output response in a plastic scintillator irradiated by a 67.5 MeV proton beam using various dosimetry parameters. The relationship of the visible scintillator light with the beam current or dose rate, aperture size and the thickness of water in the water-column was studied. The images captured on a CCD camera system were used to determine optimal dosimetry parameters for measuring the range of a clinical proton beam. The method was developed as a simple quality assurance tool to measure the range of the proton beam and compare it to (a) measurements using two segmented ionization chambers and water column between them, and (b) with an ionization chamber (IC-18) measurements in water. We used a block of plastic scintillator that measured 5 Multiplication-Sign 5 Multiplication-Sign 5 cm{sup 3} to record visible light generated by a 67.5 MeV proton beam. A high-definition digital video camera Moticam 2300 connected to a PC via USB 2.0 communication channel was used to record images of scintillation luminescence. The brightness of the visible light was measured while changing beam current and aperture size. The results were analyzed to obtain the range and were compared with the Bragg peak measurements with an ionization chamber. The luminescence light from the scintillator increased linearly with the increase of proton beam current. The light output also increased linearly with aperture size. The relationship between the proton range in the scintillator and the thickness of the water column showed good linearity with a precision of 0.33 mm (SD) in proton range measurement. For the 67.5 MeV proton beam utilized, the optimal parameters for scintillator light output response were found to be 15 nA (16 Gy/min) and an aperture size of 15 mm with image integration time of 100 ms. The Bragg peak depth brightness distribution was compared with the depth dose distribution from ionization chamber measurements

Dual-range linearized transimpedance amplifier system

Science.gov (United States)

Wessendorf, Kurt O.

2010-11-02

A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).

Voltage control in Z-source inverter using low cost microcontroller for undergraduate approach

Science.gov (United States)

Zulkifli, Shamsul Aizam; Sewang, Mohd Rizal; Salimin, Suriana; Shah, Noor Mazliza Badrul

2017-09-01

This paper is focussing on controlling the output voltage of Z-Source Inverter (ZSI) using a low cost microcontroller with MATLAB-Simulink that has been used for interfacing the voltage control at the output of ZSI. The key advantage of this system is the ability of a low cost microcontroller to process the voltage control blocks based on the mathematical equations created in MATLAB-Simulink. The Proportional Integral (PI) control equations are been applied and then, been downloaded to the microcontroller for observing the changes on the voltage output regarding to the changes on the reference on the PI. The system has been simulated in MATLAB and been verified with the hardware setup. As the results, the Raspberry Pi and Arduino that have been used in this work are able to respond well when there is a change of ZSI output. It proofed that, by applying/introducing this method to student in undergraduate level, it will help the student to understand more on the process of the power converter combine with a control feedback function that can be applied at low cost microcontroller.

47.8 GHz InPHBT quadrature VCO with 22% tuning range

DEFF Research Database (Denmark)

Hadziabdic, Dzenan; Johansen, Tom Keinicke; Krozer, Viktor

2007-01-01

A 38-47.8 GHz quadrature voltage controlled oscillator (QVCO) in InP HBT technology is presented. The measured output power is - 15 dBm. The simulated phase noise ranges from -84 to -86 dBc/Hz at 1 MHz offset. It is believed that this is the first millimetre-wavc QVCO implemented in InP HBT...

SYNTHESIS OF VOLTAGES OF UNIFORM PWM IN TIME REGULATION

Directory of Open Access Journals (Sweden)

A. G. Stryzhniou

2014-01-01

Full Text Available The article describes a process of synthesis and qualitative assessment of the harmonic composition of voltages of multiple and single PWM pulses in time regulation, being, along with amplitude, frequency and phase method, one of control methods of an asynchronous motor. The main point of time regulation is that a pause after any two single PWM pulses with different polarity or after any two groups of multiple PWM pulses with different polarity changes during a process of regulation. Feature of time regulation is that a motor has fast response in the range of small-signal of control and good linearity of speed-torque characteristics in the whole control range. Analytical expressions of parameters of PWM pulses ai and ti are obtained which allow to simplify considerably a process of formation and implementation of time regulation using tabular or indexed-tabular methods. These expressions allow not only to define voltage amplitude of  harmonic but also to perform qualitative assessment of harmonic composition of output voltages at time regulation. It is specified that harmonic frequencies wi = w0/q change in inverse proportion to magnitude of parameter q during a process of regulation and there is a replacement of a fundamental frequency by frequencies of higher harmonics.The offered approach allows to synthesize voltage of uniform single and multiple PWM pulses and to perform their comparative and qualitative analysis and the obtained expressions can be used at modeling of AC motor work. Voltage of multiple PWM pulses which is formed using stepped reference voltage with even quantity of steps in a half period and a pause on a zero level has the best parameters by criterion of a minimum of harmonic components and a maximum of a factor of anharmonicity Kнс at time regulation.

Ultra-Fast Tracking Power Supply with 4th order Output Filter and Fixed-Frequency Hysteretic Control

DEFF Research Database (Denmark)

Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

2008-01-01

A practical solution is presented for the design of a non-isolated DC/DC power converter with very low output ripple voltage and very fast output voltage step response. The converter is intended for use as an envelope tracking power supply for an RFPA (Radio Frequency Power Amplifier) in a Tetra2...

Development of anode high voltage power supply system for ECRH of HL-2A tokamak

International Nuclear Information System (INIS)

Chen Wenguang

2009-01-01

The anode high voltage power supply system consist of DC high-voltage power supply (HVPS) and pulse modulator. SCR is used to vary AC input voltage of the step-up transformer by controlling the trigger phase in the HVPS, and regulate the DC output voltage linearly at the potential of low-end via BJT, Dual closed-loop control technology is applied in the controller, and its maximum output is at 30kV and 130mA. Tetrode is the core component of the modulator. The circuit design is optimized by using the simulation software. Test and HL-2A discharge experimental results show that the power supply system is designed with some characteristics of output scale widely, low ripple and modulate quickly. (authors)

Use of medium-range numerical weather prediction model output to produce forecasts of streamflow

Science.gov (United States)

Clark, M.P.; Hay, L.E.

2004-01-01

This paper examines an archive containing over 40 years of 8-day atmospheric forecasts over the contiguous United States from the NCEP reanalysis project to assess the possibilities for using medium-range numerical weather prediction model output for predictions of streamflow. This analysis shows the biases in the NCEP forecasts to be quite extreme. In many regions, systematic precipitation biases exceed 100% of the mean, with temperature biases exceeding 3??C. In some locations, biases are even higher. The accuracy of NCEP precipitation and 2-m maximum temperature forecasts is computed by interpolating the NCEP model output for each forecast day to the location of each station in the NWS cooperative network and computing the correlation with station observations. Results show that the accuracy of the NCEP forecasts is rather low in many areas of the country. Most apparent is the generally low skill in precipitation forecasts (particularly in July) and low skill in temperature forecasts in the western United States, the eastern seaboard, and the southern tier of states. These results outline a clear need for additional processing of the NCEP Medium-Range Forecast Model (MRF) output before it is used for hydrologic predictions. Techniques of model output statistics (MOS) are used in this paper to downscale the NCEP forecasts to station locations. Forecasted atmospheric variables (e.g., total column precipitable water, 2-m air temperature) are used as predictors in a forward screening multiple linear regression model to improve forecasts of precipitation and temperature for stations in the National Weather Service cooperative network. This procedure effectively removes all systematic biases in the raw NCEP precipitation and temperature forecasts. MOS guidance also results in substantial improvements in the accuracy of maximum and minimum temperature forecasts throughout the country. For precipitation, forecast improvements were less impressive. MOS guidance increases

Mitigating voltage lead errors of an AC Josephson voltage standard by impedance matching

Science.gov (United States)

Zhao, Dongsheng; van den Brom, Helko E.; Houtzager, Ernest

2017-09-01

A pulse-driven AC Josephson voltage standard (ACJVS) generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test (DUT) at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. Error correction mechanisms investigated so far allow the ACJVS to be operational for frequencies up to 100 kHz. In this paper, calculations are presented to deal with these errors in terms of reflected waves. Impedance matching at the source side of the system, which is loaded with a high-impedance DUT, is proposed as an accurate method to mitigate these errors for frequencies up to 1 MHz. Simulations show that the influence of non-ideal component characteristics, such as the tolerance of the matching resistor, the capacitance of the load input impedance, losses in the voltage leads, non-homogeneity in the voltage leads, a non-ideal on-chip connection and inductors between the Josephson junction array and the voltage leads, can be corrected for using the proposed procedures. The results show that an expanded uncertainty of 12 parts in 106 (k  =  2) at 1 MHz and 0.5 part in 106 (k  =  2) at 100 kHz is within reach.

Optimization of voltage output of energy harvesters with continuous mechanical rotation extracted from human motion (Conference Presentation)

Science.gov (United States)

Rashid, Evan; Hamidi, Armita; Tadesse, Yonas

2017-04-01

With increasing popularity of portable devices for outdoor activities, portable energy harvesting devices are coming into spot light. The next generation energy harvester which is called hybrid energy harvester can employ more than one mechanism in a single device to optimize portion of the energy that can be harvested from any source of waste energy namely motion, vibration, heat and etc. In spite of few recent attempts for creating hybrid portable devices, the level of output energy still needs to be improved with the intention of employing them in commercial electronic systems or further applications. Moreover, implementing a practical hybrid energy harvester in different application for further investigation is still challenging. This proposal is projected to incorporate a novel approach to maximize and optimize the voltage output of hybrid energy harvesters to achieve a greater conversion efficiency normalized by the total mass of the hybrid device than the simple arithmetic sum of the individual harvesting mechanisms. The energy harvester model previously proposed by Larkin and Tadesse [1] is used as a baseline and a continuous unidirectional rotation is incorporated to maximize and optimize the output. The device harvest mechanical energy from oscillatory motion and convert it to electrical energy through electromagnetic and piezoelectric systems. The new designed mechanism upgrades the device in a way that can harvest energy from both rotational and linear motions by using magnets. Likewise, the piezoelectric section optimized to harvest at least 10% more energy. To the end, the device scaled down for tested with different sources of vibrations in the immediate environment, including machinery operation, bicycle, door motion while opening and closing and finally, human motions. Comparing the results from literature proved that current device has capability to be employed in commercial small electronic devices for enhancement of battery usage or as a backup

Determination of the aging offset voltage of AMR sensors based on accelerated degradation test

NARCIS (Netherlands)

Zambrano Constantini, A.C.; Kerkhoff, Hans G.

Usually Anisotropic Magnetoresistance angle sensors are configured with two Wheatstone bridges, but an undesirable offset voltage included in the sensor output affects its accuracy. The total offset voltage combines a voltage due to resistance mismatches during manufacturing and a voltage from

Simple programmable voltage reference for low frequency noise measurements

Science.gov (United States)

Ivanov, V. E.; Chye, En Un

2018-05-01

The paper presents a circuit design of a low-noise voltage reference based on an electric double-layer capacitor, a microcontroller and a general purpose DAC. A large capacitance value (1F and more) makes it possible to create low-pass filter with a large time constant, effectively reducing low-frequency noise beyond its bandwidth. Choosing the optimum value of the resistor in the RC filter, one can achieve the best ratio between the transient time, the deviation of the output voltage from the set point and the minimum noise cut-off frequency. As experiments have shown, the spectral density of the voltage at a frequency of 1 kHz does not exceed 1.2 nV/√Hz the maximum deviation of the output voltage from the predetermined does not exceed 1.4 % and depends on the holding time of the previous value. Subsequently, this error is reduced to a constant value and can be compensated.

Wide-Range Adaptive RF-to-DC Power Converter for UHF RFIDs

KAUST Repository

Ouda, Mahmoud H.

2016-07-27

A wide-range, differential, cross-coupled rectifier is proposed with an extended dynamic range of input RF power that enables wireless powering from varying distances. The proposed architecture mitigates the reverse-leakage problem in conven- tional, cross-coupled rectifiers without degrading sensitivity. A prototype is designed for UHF RFID applications, and is imple- mented using 0.18 μ m CMOS technology. On-chip measurements demonstrate a sensitivity of − 18 dBm for 1 V output over a 100 k Ω load and a peak RF-to-DC power conversion efficiency of 65%. A conventional, fully cross-coupled rectifier is fabricated along- side for comparison and the proposed rectifier shows more than 2 × increase in dynamic range and a 25% boosting in output voltage than the conventional rectifier

Component-Minimized Buck-Boost Voltage Source Inverters

DEFF Research Database (Denmark)

Gao, F.; Loh, P.C.; Blaabjerg, Frede

2007-01-01

This paper presents the design of buck-boost B4 inverters that can be derived from either Ćuk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion...... between capacitors. Modulation wise, the proposed buck-boost B4 inverters can be controlled using a carefully designed carrier-based pulse-width modulation (PWM) scheme that will always ensure balanced threephase outputs as desired, while simultaneously achieving minimal voltage stress across...

Influence of illumination on the output characteristics in pentacene thin film transistors

Energy Technology Data Exchange (ETDEWEB)

Lin, Yow-Jon, E-mail: rzr2390@yahoo.com.tw; Huang, Bo-Chieh

2013-10-01

The influence of illumination on the output characteristics of pentacene-based organic thin film transistors (OTFTs) was researched in this study. It is shown that light illumination may lead to an increase in the drain current, shifting the threshold voltage towards positive gate–source voltages. This is because of the light-induced acceptor activation, which is a new concept for illumination-dependent output characteristics of OTFTs. However, the field-effect mobility is insensitive to light illumination. It is found that electron trapping is responsible for the experimentally observed illumination-dependent output behavior of charge transport in OTFTs. - Highlights: • Light illumination may lead to an increase in the drain current. • This is because of the light-induced acceptor activation. • The field-effect mobility is insensitive to light illumination. • Electron trapping is responsible for the illumination-dependent output behavior.

Interconnected High-Voltage Pulsed-Power Converters System Design for H− Ion Sources

CERN Document Server

Aguglia, D

2014-01-01

This paper presents the design and experimental validations of a system of three new high-voltage (HV) pulsedpower converters for the H− sources. The system requires three pulsed voltages (50, 40, and 25 kV to ground) at 2-Hz repetition rate, for 700 μs of usable flat-top. The solution presents ripplefree output voltages and minimal stored energy to protect the ion source from the consequences of arc events. Experimental results on the final full-scale prototype are presented. In case of short-circuit events, the maximal energy delivered to the source is in the Joule range. HV flat-top stability of 1% is experimentally achieved with a simple Proportional-Integral- Derivative regulation and preliminary tuned H− source (e.g., radio frequency control, gas injection, and so forth). The system is running since more than a year with no power converter failures and damage to the source.

A New Asymmetrical Current-fed Converter with Voltage Lifting

Directory of Open Access Journals (Sweden)

DELSHAD, M.

2011-05-01

Full Text Available This paper presents a new zero voltage switching current-fed DC-DC converter with high voltage gain. In this converter all switches (main and auxiliary turn on under zero voltage switching and turn off under almost zero voltage switching due to snubber capacitor. Furthermore, the voltage spike across the main switch due to leakage inductance of forward transformer is absorbed. The flyback transformer which is connected to the output in series causes to high voltage gain and less voltage stress on the power devices. Considering high efficiency and voltage gain of this converter, it is suitable for green generated systems such as fuel cells or photovoltaic systems. The presented experimental results verify the integrity of the proposed converter.

Improved transmission of electrostatic accelerator in a wide range of terminal voltages by controlling the focal strength of entrance acceleration tube

Science.gov (United States)

Lobanov, Nikolai R.; Tunningley, Thomas; Linardakis, Peter

2018-04-01

Tandem electrostatic accelerators often require the flexibility to operate at a variety of terminal voltages to accommodate various user requirements. However, the ion beam transmission will only be optimal for a limited range of terminal voltages. This paper describes the operational performance of a novel focusing system that expands the range of terminal voltages for optimal transmission. This is accomplished by controlling the gradient of the entrance of the low-energy tube, providing an additional focusing element. In this specific case it is achieved by applying up to 150 kV to the fifth electrode of the first unit of the accelerator tube. Numerical simulations and beam transmission tests have been performed to confirm the effectiveness of the lens. An analytical expression has been derived describing its focal properties. These tests demonstrate that the entrance lens control eliminates the need to short out sections of the tube for operation at low terminal voltage.

Design and analysis of optimised class E power amplifier using shunt capacitance in the output structure

Science.gov (United States)

Hayati, Mohsen; Roshani, Sobhan; Zirak, Ali Reza

2017-05-01

In this paper, a class E power amplifier (PA) with operating frequency of 1 MHz is presented. MOSFET non-linear drain-to-source parasitic capacitance, linear external capacitance at drain-to-source port and linear shunt capacitance in the output structure are considered in design theory. One degree of freedom is added to the design of class E PA, by assuming the shunt capacitance in the output structure in the analysis. With this added design degree of freedom it is possible to achieve desired values for several parameters, such as output voltage, load resistance and operating frequency, while both zero voltage and zero derivative switching (ZVS and ZDS) conditions are satisfied. In the conventional class E PA, high value of peak switch voltage results in limitations for the design of amplifier, while in the presented structure desired specifications could be achieved with the safe margin of peak switch voltage. The results show that higher operating frequency and output voltage can also be achieved, compared to the conventional structure. PSpice software is used in order to simulate the designed circuit. The presented class E PA is designed, fabricated and measured. The measured results are in good agreement with simulation and theory results.

Static inverter with synchronous output waveform synthesized by time-optimal-response feedback

Science.gov (United States)

Kernick, A.; Stechschulte, D. L.; Shireman, D. W.

1976-01-01

Time-optimal-response 'bang-bang' or 'bang-hang' technique, using four feedback control loops, synthesizes static-inverter sinusoidal output waveform by self-oscillatory but yet synchronous pulse-frequency-modulation (SPFM). A single modular power stage per phase of ac output entails the minimum of circuit complexity while providing by feedback synthesis individual phase voltage regulation, phase position control and inherent compensation simultaneously for line and load disturbances. Clipped sinewave performance is described under off-limit load or input voltage conditions. Also, approaches to high power levels, 3-phase arraying and parallel modular connection are given.

Novel composite resonance DC-DC converter with voltage doubler rectifier

OpenAIRE

Kato, Hisatsugu; Matsuo, Hirohumi; Eguchi, Masaki; Sakamoto, Yukitaka; Nakaishi, Masaki

2009-01-01

This paper deals with a novel composite resonance DC-DC converter with the voltage doubler rectifier, which is developed to be applied to the power conditioner of the photovoltaic generation system. The proposed DC-DC converter has the current and voltage resonance functions. Therefore, the output voltage regulation can be achieved for the large variations of the input voltage and load. Also, this converter has the high power efficiency. The maximum power efficiency 96.1% can be realized.

Load Insensitive, Low Voltage Quadrature Oscillator Using Single Active Element

Directory of Open Access Journals (Sweden)

Jitendra Mohan

2017-01-01

Full Text Available In this paper, a load insensitive quadrature oscillator using single differential voltage dual-X second generation current conveyor operated at low voltage is proposed. The proposed circuit employs single active element, three grounded resistors and two grounded capacitors. The proposed oscillator offers two load insensitive quadrature current outputs and three quadrature voltage outputs simultaneously. Effects of non-idealities along with the effects of parasitic are further studied. The proposed circuit enjoys the feature of low active and passive sensitivities. Additionally, a resistorless realization of the proposed quadrature oscillator is also explored. Simulation results using PSPICE program on cadence tool using 90 nm Complementary Metal Oxide Semiconductor (CMOS process parameters confirm the validity and practical utility of the proposed circuit.

The high voltage homopolar generator

Science.gov (United States)

Price, J. H.; Gully, J. H.; Driga, M. D.

1986-11-01

System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

Experimental Investigation of the Effect of the Driving Voltage of an Electroadhesion Actuator

Directory of Open Access Journals (Sweden)

Keng Huat Koh

2014-06-01

Full Text Available This paper investigates the effect of driving voltage on the attachment force of an electroadhesion actuator, as the existing literature on the saturation of the adhesive force at a higher electric field is incomplete. A new type of electroadhesion actuator using normally available materials, such as aluminum foil, PVC tape and a silicone rubber sheet used for keyboard protection, has been developed with a simple layered structure that is capable of developing adhesive force consistently. The developed actuator is subjected to the experiment for the evaluation of various test surfaces; aluminum, brick, ceramic, concrete and glass. The driving high voltage is varied in steps to determine the characteristics of the output holding force. Results show a quadratic relation between F (adhesion force and V (driving voltage within the 2 kV range. After this range, the F-V responses consistently show a saturation trend at high electric fields. Next, the concept of the leakage current that can occur in the dielectric material and the corona discharge through air has been introduced. Results show that the voltage level, which corresponds to the beginning of the supply current, matches well with the beginning of the force saturation. With the confirmation of this hypothesis, a working model for electroadhesion actuation is proposed. Based on the experimental results, it is proposed that such a kind of actuator can be driven within a range of optimum high voltage to remain electrically efficient. This practice is recommended for the future design, development and characterization of electroadhesion actuators for robotic applications.

Experimental Investigation of the Effect of the Driving Voltage of an Electroadhesion Actuator.

Science.gov (United States)

Koh, Keng Huat; Sreekumar, M; Ponnambalam, S G

2014-06-25

This paper investigates the effect of driving voltage on the attachment force of an electroadhesion actuator, as the existing literature on the saturation of the adhesive force at a higher electric field is incomplete. A new type of electroadhesion actuator using normally available materials, such as aluminum foil, PVC tape and a silicone rubber sheet used for keyboard protection, has been developed with a simple layered structure that is capable of developing adhesive force consistently. The developed actuator is subjected to the experiment for the evaluation of various test surfaces; aluminum, brick, ceramic, concrete and glass. The driving high voltage is varied in steps to determine the characteristics of the output holding force. Results show a quadratic relation between F (adhesion force) and V (driving voltage) within the 2 kV range. After this range, the F - V responses consistently show a saturation trend at high electric fields. Next, the concept of the leakage current that can occur in the dielectric material and the corona discharge through air has been introduced. Results show that the voltage level, which corresponds to the beginning of the supply current, matches well with the beginning of the force saturation. With the confirmation of this hypothesis, a working model for electroadhesion actuation is proposed. Based on the experimental results, it is proposed that such a kind of actuator can be driven within a range of optimum high voltage to remain electrically efficient. This practice is recommended for the future design, development and characterization of electroadhesion actuators for robotic applications.

Fault Modeling and Testing for Analog Circuits in Complex Space Based on Supply Current and Output Voltage

Directory of Open Access Journals (Sweden)

Hongzhi Hu

2015-01-01

Full Text Available This paper deals with the modeling of fault for analog circuits. A two-dimensional (2D fault model is first proposed based on collaborative analysis of supply current and output voltage. This model is a family of circle loci on the complex plane, and it simplifies greatly the algorithms for test point selection and potential fault simulations, which are primary difficulties in fault diagnosis of analog circuits. Furthermore, in order to reduce the difficulty of fault location, an improved fault model in three-dimensional (3D complex space is proposed, which achieves a far better fault detection ratio (FDR against measurement error and parametric tolerance. To address the problem of fault masking in both 2D and 3D fault models, this paper proposes an effective design for testability (DFT method. By adding redundant bypassing-components in the circuit under test (CUT, this method achieves excellent fault isolation ratio (FIR in ambiguity group isolation. The efficacy of the proposed model and testing method is validated through experimental results provided in this paper.

Simulating threshold voltage shift of MOS devices due to radiation in the low-dose range

CERN Document Server

Wan Xin Heng; Gao Wen Yu; Huang Ru; Wang Yang Yuan

2002-01-01

An analytical MOSFET threshold voltage shift model due to radiation in the low-dose range has been developed for circuit simulations. Experimental data in the literature shows that the model predictions are in good agreement. It is simple in functional form and hence computationally efficient. It can be used as a basic circuit simulation tool for analysing MOSFET exposed to a nuclear environment up to about 1 Mrad(Si). In accordance with common believe, radiation induced absolute change of threshold voltage was found to be larger in irradiated PMOS devices. However, if the radiation sensitivity is defined in the way authors did it, the results indicated NMOS rather than PMOS devices are more sensitive, specially at low doses. This is important from the standpoint of their possible application in dosimetry

Control design for a wind turbine-generator using output feedback

Science.gov (United States)

Javid, S. H.; Murdoch, A.; Winkelman, J. R.

1981-01-01

The modeling and approach to control design for a large horizontal axis wind turbine (WT) generator are presented. The control design is based on a suboptimal output regulator which allows coordinated control of WT blade pitch angle and field voltage for the purposes of regulating electrical power and terminal voltage. Results of detailed non-linear simulation tests of this controller are shown.

Variable self-powered light detection CMOS chip with real-time adaptive tracking digital output based on a novel on-chip sensor.

Science.gov (United States)

Wang, HongYi; Fan, Youyou; Lu, Zhijian; Luo, Tao; Fu, Houqiang; Song, Hongjiang; Zhao, Yuji; Christen, Jennifer Blain

2017-10-02

This paper provides a solution for a self-powered light direction detection with digitized output. Light direction sensors, energy harvesting photodiodes, real-time adaptive tracking digital output unit and other necessary circuits are integrated on a single chip based on a standard 0.18 µm CMOS process. Light direction sensors proposed have an accuracy of 1.8 degree over a 120 degree range. In order to improve the accuracy, a compensation circuit is presented for photodiodes' forward currents. The actual measurement precision of output is approximately 7 ENOB. Besides that, an adaptive under voltage protection circuit is designed for variable supply power which may undulate with temperature and process.

OFCC based voltage and transadmittance mode instrumentation amplifier

Science.gov (United States)

Nand, Deva; Pandey, Neeta; Pandey, Rajeshwari; Tripathi, Prateek; Gola, Prashant

2017-07-01

The operational floating current conveyor (OFCC) is a versatile active block due to the availability of both low and high input and output impedance terminals. This paper addresses the realization of OFCC based voltage and transadmittance mode instrumentation amplifiers (VMIA and TAM IA). It employs three OFCCs and seven resistors. The transadmittance mode operation can easily be obtained by simply connecting an OFCC based voltage to current converter at the output. The effect of non-idealities of OFCC, in particular finite transimpedance and tracking error, on system performance is also dealt with and corresponding mathematical expressions are derived. The functional verification is performed through SPICE simulation using CMOS based implementation of OFCC.

Ultra-low Voltage CMOS Cascode Amplifier

OpenAIRE

Lehmann, Torsten; Cassia, Marco

2000-01-01

In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique, which reduces the MOST threshold voltage by forcing a constant current though the transistor bulk terminal. We also look at limitations and improvements of this CDB technique.

Ultra-low Voltage CMOS Cascode Amplifier

DEFF Research Database (Denmark)

Lehmann, Torsten; Cassia, Marco

2000-01-01

In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique......, which reduces the MOST threshold voltage by forcing a constant current though the transistor bulk terminal. We also look at limitations and improvements of this CDB technique....

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

A high-efficiency low-voltage class-E PA for IoT applications in sub-1 GHz frequency range

Science.gov (United States)

Zhou, Chenyi; Lu, Zhenghao; Gu, Jiangmin; Yu, Xiaopeng

2017-10-01

We present and propose a complete and iterative integrated-circuit and electro-magnetic (EM) co-design methodology and procedure for a low-voltage sub-1 GHz class-E PA. The presented class-E PA consists of the on-chip power transistor, the on-chip gate driving circuits, the off-chip tunable LC load network and the off-chip LC ladder low pass filter. The design methodology includes an explicit design equation based circuit components values' analysis and numerical derivation, output power targeted transistor size and low pass filter design, and power efficiency oriented design optimization. The proposed design procedure includes the power efficiency oriented LC network tuning, the detailed circuit/EM co-simulation plan on integrated circuit level, package level and PCB level to ensure an accurate simulation to measurement match and first pass design success. The proposed PA is targeted to achieve more than 15 dBm output power delivery and 40% power efficiency at 433 MHz frequency band with 1.5 V low voltage supply. The LC load network is designed to be off-chip for the purpose of easy tuning and optimization. The same circuit can be extended to all sub-1 GHz applications with the same tuning and optimization on the load network at different frequencies. The amplifier is implemented in 0.13 μm CMOS technology with a core area occupation of 400 μm by 300 μm. Measurement results showed that it provided power delivery of 16.42 dBm at antenna with efficiency of 40.6%. A harmonics suppression of 44 dBc is achieved, making it suitable for massive deployment of IoT devices. Project supported by the National Natural Science Foundation of China (No. 61574125) and the Industry Innovation Project of Suzhou City of China (No. SYG201641).

A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

Directory of Open Access Journals (Sweden)

Yabiao Gao

2015-08-01

Full Text Available The efficiency of wireless power transfer is sensitive to the horizontal and vertical distances between the transmitter and receiver coils due to the magnetic coupling change. To address the output voltage variation and efficiency drop caused by misalignment, a uniform voltage gain frequency control is implemented to improve the power delivery and efficiency of wireless power transfer under misalignment. The frequency is tuned according to the amplitude and phase-frequency characteristics of coupling variations in order to maintain a uniform output voltage in the receiver coil. Experimental comparison of three control methods, including fixed frequency control, resonant frequency control, and the proposed uniform gain control was conducted and demonstrated that the uniform voltage gain control is the most robust method for managing misalignment in wireless charging applications.

A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

2016-01-01

Passive trap filters are widely used in high power Voltage Source Inverters (VSI) for the switching harmonic attenuation. The usage of the passive trap filters requires clustered and fixed switching harmonic spectrum, which is not the case for low pulse-ratio or Variable Switching Frequency (VSF...... current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...

New topology of multiple-input single-output PV system for DC load applications

Directory of Open Access Journals (Sweden)

Mohsen M. ELhagry

2016-12-01

Full Text Available Improving PV system structure and maximizing the output power of a PV system has drawn many researchers attention nowadays. A proposed multi-input single-output PV system is proposed in this paper. The system consists of multiple PV modules; each module feeds a DC–DC converter. The outputs of the converters are tied together to form a DC voltage source. In order to minimize the output ripples of the converters, the control signal of each converter is time shifted from each other by a certain time interval depending on the number of converters used in the topology. In this study a battery is used as the main load, the load current used as the control variable. A fuzzy logic controller designed to modulate the operating point of the system to get the maximum power. The results show that the proposed system has very good response for various operating conditions of the PV system. In addition the output filter is minimized with excellent quality of the DC output voltage.

250 kV 6 mA compact Cockcroft-Walton high-voltage power supply

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhan-Wen; Su, Xiao-Dong; Wei, Zhen; Huang, Zhi-Wu; Miao, Tian-You; Su, Tong-Ling [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Lu, Xiao-Long; Wang, Jun-Run; Yao, Ze-En, E-mail: zeyao@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

2016-08-15

A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm. Test results indicate that the maximum output voltage of the power supply is 282 kV, and the stability of the output voltage is better than 0.63% when the high voltage power supply is operated at 250 kV, 6.9 mA with the input voltage varying ±10%.

Differential Amplifier with Current-Mirror Load: Influence of Current Gain, Early Voltage, and Supply Voltage on the DC Output Voltage

Science.gov (United States)

Paulik, G. F.; Mayer, R. P.

2012-01-01

A differential amplifier composed of an emitter-coupled pair is useful as an example in lecture presentations and laboratory experiments in electronic circuit analysis courses. However, in an active circuit with zero input load V[subscript id], both laboratory measurements and PSPICE and LTspice simulation results for the output voltage…

A current-mode voltage regulator with an embedded sub-threshold reference for a passive UHF RFID transponder

Energy Technology Data Exchange (ETDEWEB)

Liu Zhongqi [Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China); Zhang Chun; Li Yongming; Wang Zhihua, E-mail: liu-zq04@mails.tsinghua.edu.c [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2010-06-15

This paper presents a current-mode voltage regulator for a passive UHF RFID transponder. The passive tag power is extracted from RF energy through the RF-to-DC rectifier. Due to huge variations of the incoming RF power, the rectifier output voltage should be regulated to achieve a stable power supply. By accurately controlling the current flowing into the load with an embedded sub-threshold reference, the regulated voltage varies in a range of 1-1.3 V from -20 to 80 {sup 0}C, and a bandwidth of about 100 kHz is achieved for a fast power recovery. The circuit is fabricated in UMC 0.18 {mu}m mixed-mode CMOS technology, and the current consumption is only 1 {mu}A. (semiconductor integrated circuits)

A current-mode voltage regulator with an embedded sub-threshold reference for a passive UHF RFID transponder

International Nuclear Information System (INIS)

Liu Zhongqi; Zhang Chun; Li Yongming; Wang Zhihua

2010-01-01

This paper presents a current-mode voltage regulator for a passive UHF RFID transponder. The passive tag power is extracted from RF energy through the RF-to-DC rectifier. Due to huge variations of the incoming RF power, the rectifier output voltage should be regulated to achieve a stable power supply. By accurately controlling the current flowing into the load with an embedded sub-threshold reference, the regulated voltage varies in a range of 1-1.3 V from -20 to 80 0 C, and a bandwidth of about 100 kHz is achieved for a fast power recovery. The circuit is fabricated in UMC 0.18 μm mixed-mode CMOS technology, and the current consumption is only 1 μA. (semiconductor integrated circuits)

The development of long pulse high voltage power supply for MNI-1U neutral beam injector

International Nuclear Information System (INIS)

Detai Wang

1989-01-01

A high power long pulse high voltage power supply (HVPS) for MNI- 1 U neutral beam injector (NBI) is described. This HVPS is used as a switching regulator with a duty cycle of 1/100, the specifications of circuit are as follows, output pulse voltage 50kv, pulse current 30A, pulse width 50ms, rise-time and fall-time of the voltage are less than 25 μs, stability of the pulse flat is better than 0.5%, regulation response time of the pulse voltage less than 30 μs can be attained. It is also used as a stable DC HVPS, output voltage is 1 to 100kv, current is 1 to 5A. If regulation tube is shunted with high power resistor in parallel, the current can be extended to 10 A, stability of the output voltage or current is better than 0.1%. Now, the HVPS has been put into operation for MNI- 1 U NBI and PIG ion source made in French. 3 refs., 5 figs

Electronic voltage and current transformers testing device.

Science.gov (United States)

Pan, Feng; Chen, Ruimin; Xiao, Yong; Sun, Weiming

2012-01-01

A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs) with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation signal is fed to their primaries. The test that estimates the performance of the prototype has been carried out at the National Centre for High Voltage Measurement and the prototype is approved for testing transformers with precision class up to 0.2 at the industrial frequency (50 Hz or 60 Hz). The device is suitable for on-site testing due to its high accuracy, simple structure and low-cost hardware.

Note: A 102 dB dynamic-range charge-sampling readout for ionizing particle/radiation detectors based on an application-specific integrated circuit (ASIC)

Science.gov (United States)

Pullia, A.; Zocca, F.; Capra, S.

2018-02-01

An original technique for the measurement of charge signals from ionizing particle/radiation detectors has been implemented in an application-specific integrated circuit form. The device performs linear measurements of the charge both within and beyond its output voltage swing. The device features an unprecedented spectroscopic dynamic range of 102 dB and is suitable for high-resolution ion and X-γ ray spectroscopy. We believe that this approach may change a widespread paradigm according to which no high-resolution spectroscopy is possible when working close to or beyond the limit of the preamplifier's output voltage swing.

High-Voltage, Low-Power BNC Feedthrough Terminator

Science.gov (United States)

Bearden, Douglas

2012-01-01

This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

Analysis of dc-Link Voltage Switching Ripple in Three-Phase PWM Inverters

Directory of Open Access Journals (Sweden)

Marija Vujacic

2018-02-01

Full Text Available The three-phase voltage source inverter (VSI is de facto standard in power conversion systems. To realize high power density systems, one of the items to be correctly addressed is the design and selection of the dc-link capacitor in relation to the voltage switching ripple. In this paper, effective formulas for designing the dc-link capacitor as a function of the switching voltage ripple amplitude are obtained, considering the operating conditions such as the modulation index and the output current amplitude. The calculations are obtained considering the requirements and restrictions referring to the high (switching-frequency dc-link voltage ripple component. Analyses have been performed considering the dc source impedance (non-ideal dc voltage source at the switching frequency and a balanced load. Analytical expressions are derived for the dc-link voltage switching ripple amplitude and its maximum value over the fundamental period. Different values of modulation index and output phase angle have been considered and different diagrams are presented. Analytical results were validated both by simulations and comprehensive experimental tests.

Fast Reactive Power Sharing, Circulating Current and Resonance Suppression for Parallel Inverters Using Resistive-Capacitive Output Impedance

DEFF Research Database (Denmark)

Chen, Yandong; Guerrero, Josep M.; Shuai, Zhikang

2016-01-01

In this paper, an inverter using resistivecapacitive output impedance (RC-type inverter) is proposed not only to provide fast reactive power sharing to support microgrid voltage, and but also to reduce circulating currents and damp high-frequency resonances among inverters. Introducing the RC......-frequency resonances among parallel inverters are quantitatively analyzed. The control parameters are systematically selected, and effect of virtual complex impedance on the inverter output voltage is depicted. The RC-type inverter can reduce circulating currents and damp resonances due to different equivalent output...

A voltage regulator system with dynamic bandwidth boosting for passive UHF RFID transponders

International Nuclear Information System (INIS)

Shen Jinpeng; Wang Xin'an; Liu Shan; Li Shoucheng; Ruan Zhengkun

2013-01-01

This paper presents a voltage regulator system for passive UHF RFID transponders, which contains a rectifier, a limiter, and a regulator. The rectifier achieves power by rectifying the incoming RF energy. Due to the huge variation of the rectified voltage, a limiter at the rectifier output is used to clamp the rectified voltage. In this paper, the design of a limiter circuit is discussed in detail, which can provide a stable limiting voltage with low sensitivity to temperature variation and process dispersion. The key aspect of the voltage regulator system is the dynamic bandwidth boosting in the regulator. By sensing the excess current that is bypassed in the limiter during periods of excess energy, the bias current as well as the bandwidth of the regulator are increased, the output supply voltage can recover quickly from line transients during the periods of no RF energy to a full blast of RF energy. This voltage regulator system is implemented in a 0.18 μm CMOS process. (semiconductor integrated circuits)

Systematic evaluation of a secondary method for measuring diagnostic-level medical ultrasound transducer output power based on a large-area pyroelectric sensor

Science.gov (United States)

Zeqiri, B.; Žauhar, G.; Rajagopal, S.; Pounder, A.

2012-06-01

A systematic study of the application of a novel pyroelectric technique to the measurement of diagnostic-level medical ultrasound output power is described. The method exploits the pyroelectric properties of a 0.028 mm thick membrane of polyvinylidene fluoride (PVDF), backed by an acoustic absorber whose ultrasonic absorption coefficient approaches 1000 dB cm-1 at 3 MHz. When exposed to an ultrasonic field, absorption of ultrasound adjacent to the PVDF-absorber interface results in heating and the generation of a pyroelectric output voltage across gold electrodes deposited on the membrane. For a sensor large enough to intercept the whole of the acoustic beam, the output voltage can be calibrated for the measurement of acoustic output power. A number of key performance properties of the method have been investigated. The technique is very sensitive, with a power to voltage conversion factor of typically 0.23 V W-1. The frequency response of a particular embodiment of the sensor in which acoustic power reflected at the absorber-PVDF interface is subsequently returned to the pyroelectric membrane to be absorbed, has been evaluated over the frequency range 1.5 MHz to 10 MHz. This has shown the frequency response to be flat to within ±4%, above 2.5 MHz. Below this frequency, the sensitivity falls by 20% at 1.5 MHz. Linearity of the technique has been demonstrated to within ±1.6% for applied acoustic power levels from 1 mW up to 120 mW. A number of other studies targeted at assessing the achievable measurement uncertainties are presented. These involve: the effects of soaking, the influence of the angle of incidence of the acoustic beam, measurement repeatability and sensitivity to transducer positioning. Additionally, over the range 20 °C to 30 °C, the rate of change in sensitivity with ambient temperature has been shown to be +0.5% °C-1. Implications of the work for the development of a sensitive, traceable, portable, secondary method of ultrasound output power

A high voltage pulse generator based on silicon-controlled rectifier for field-reversed configuration experiment.

Science.gov (United States)

Lin, Munan; Liu, Ming; Zhu, Guanghui; Wang, Yanpeng; Shi, Peiyun; Sun, Xuan

2017-08-01

A high voltage pulse generator based on a silicon-controlled rectifier has been designed and implemented for a field reversed configuration experiment. A critical damping circuit is used in the generator to produce the desired pulse waveform. Depending on the load, the rise time of the output trigger signal can be less than 1 μs, and the peak amplitudes of trigger voltage and current are up to 8 kV and 85 A in a single output. The output voltage can be easily adjusted by changing the voltage on a capacitor of the generator. In addition, the generator integrates an electrically floating heater circuit so it is capable of triggering either pseudosparks (TDI-type hydrogen thyratron) or ignitrons. Details of the circuits and their implementation are described in the paper. The trigger generator has successfully controlled the discharging sequence of the pulsed power supply for a field reversed configuration experiment.

Performance Analysis of Phase Controlled Unidirectional and Bidirectional AC Voltage Controllers

Directory of Open Access Journals (Sweden)

Abdul Sattar Larik

2011-01-01

Full Text Available AC voltage controllers are used to vary the output ac voltage from a fixed ac input source. They are also commonly called ac voltage regulators or ac choppers. The output voltage is either controlled by PAC (Phase Angle Control method or on-off control method. Due to various advantages of ac voltage controllers, such as high efficiency, simplicity, low cost and ability to control large amount of power they efficiently control the speed of ac motors, light dimming and industrial heating, etc. These converters are variable structure systems and generate harmonics during the operation which will affect the power quality when connected to system network. During the last couple of years, a number of new semiconductor devices and various power electronic converters has been introduced. Accordingly the subject of harmonics and its problems are of great concern to power industry and customers. In this research work, initially the simulation models of single phase unidirectional and bidirectional ac voltage controllers were developed by using MATLAB software. The harmonics of these models are investigated by simulation. In the end, the harmonics were also analyzed experimentally. The simulated as well as experimental results are presented.

A Novel Output Filter Topology to Reduce Motor Overvoltage

DEFF Research Database (Denmark)

Hanigovszki, Norbert; Poulsen, Joern; Blaabjerg, Frede

2004-01-01

When an induction machine is supplied with a voltage-source pulsewidth-modulation (PWM) inverter, a ringing voltage overshoot appears at motor terminals due to steep PWM voltage pulse propagation along the motor cable. It has been reported that in particular situations, when very long motor cable....... The proposed filter drastically reduces the voltage overshoot at the motor terminals, thus reducing motor insulation stress. This is a cheap alternative to more known industrial solutions. LC...... are used and retrofit installations, the overvoltage could stress motors with poor insulation. This paper presents a novel inverter output filter topology consisting of an filter which has the star point of the common-mode capacitors clamped to the + and ? dc-link rails by the means of two diodes...

Dynamic characteristics of an orthogonal turbine and output-control systems for TPP with high-voltage frequency converter

Energy Technology Data Exchange (ETDEWEB)

Berlin, V. V.; Murav' ev, O. A.; Golubev, A. V.

2012-03-15

A mathematical description of a closed control system with allowance for pressure fluctuations in the head system, which makes it possible to analyze the regime stability of orthogonal generating sets at tidal electric power plants when operating in the complete range of heads, outputs, and rotational speeds, and to select parameters of the control system, is obtained for an orthogonal hydroturbine and a generator with a load regulator.

Dynamic characteristics of an orthogonal turbine and output-control systems for TPP with high-voltage frequency converter

International Nuclear Information System (INIS)

Berlin, V. V.; Murav’ev, O. A.; Golubev, A. V.

2012-01-01

A mathematical description of a closed control system with allowance for pressure fluctuations in the head system, which makes it possible to analyze the regime stability of orthogonal generating sets at tidal electric power plants when operating in the complete range of heads, outputs, and rotational speeds, and to select parameters of the control system, is obtained for an orthogonal hydroturbine and a generator with a load regulator.

Dose-rate effects of low-dropout voltage regulator at various biases

International Nuclear Information System (INIS)

Wang Yiyuan; Zheng Yuzhan; Gao Bo; Chen Rui; Fei Wuxiong; Lu Wu; Ren Diyuan

2010-01-01

A low-dropout voltage regulator, LM2941, was irradiated by 60 Co γ-rays at various dose rates and biases for investigating the total dose and dose rate effects. The radiation responses show that the key electrical parameters, including its output and dropout voltage, and the maximum output current, are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias. The integrated circuits damage change with the dose rates and biases, and the dose-rate effects are relative to its electric field. (authors)

A 350 KV nanosecond pulse voltage generator with adjustable pulsed-width

International Nuclear Information System (INIS)

Wang, X.; Wang, M.; Chen, Y.Q.; Zeng, L.G.; Han, M.

2002-01-01

This paper presents a 350 kV nanosecond pulse voltage generator (NPVG). The voltage pulsed-width can be adjusted from 30 to 160 ns. The generator consists of: Marx generator, pulsed forming line (PFL), main switch and matched impedance. The output voltage of Marx generator is over than nU c (n- the stage number of Marx generator, U c -the charging voltage of capacitor). When the pulse forming line is terminated with an impedance that is over than the characteristic impedance of PFL, the higher voltage pulse was provided for the load

Design of High-Voltage Switch-Mode Power Amplifier Based on Digital-Controlled Hybrid Multilevel Converter

Directory of Open Access Journals (Sweden)

Yanbin Hou

2016-01-01

Full Text Available Compared with conventional Class-A, Class-B, and Class-AB amplifiers, Class-D amplifier, also known as switching amplifier, employs pulse width modulation (PWM technology and solid-state switching devices, capable of achieving much higher efficiency. However, PWM-based switching amplifier is usually designed for low-voltage application, offering a maximum output voltage of several hundred Volts. Therefore, a step-up transformer is indispensably adopted in PWM-based Class-D amplifier to produce high-voltage output. In this paper, a switching amplifier without step-up transformer is developed based on digital pulse step modulation (PSM and hybrid multilevel converter. Under the control of input signal, cascaded power converters with separate DC sources operate in PSM switch mode to directly generate high-voltage and high-power output. The relevant topological structure, operating principle, and design scheme are introduced. Finally, a prototype system is built, which can provide power up to 1400 Watts and peak voltage up to ±1700 Volts. And the performance, including efficiency, linearity, and distortion, is evaluated by experimental tests.

Modulating the Voltage-sensitivity of a Genetically Encoded Voltage Indicator.

Science.gov (United States)

Jung, Arong; Rajakumar, Dhanarajan; Yoon, Bong-June; Baker, Bradley J

2017-10-01

Saturation mutagenesis was performed on a single position in the voltage-sensing domain (VSD) of a genetically encoded voltage indicator (GEVI). The VSD consists of four transmembrane helixes designated S1-S4. The V220 position located near the plasma membrane/extracellular interface had previously been shown to affect the voltage range of the optical signal. Introduction of polar amino acids at this position reduced the voltage-dependent optical signal of the GEVI. Negatively charged amino acids slightly reduced the optical signal by 33 percent while positively charge amino acids at this position reduced the optical signal by 80%. Surprisingly, the range of V220D was similar to that of V220K with shifted optical responses towards negative potentials. In contrast, the V220E mutant mirrored the responses of the V220R mutation suggesting that the length of the side chain plays in role in determining the voltage range of the GEVI. Charged mutations at the 219 position all behaved similarly slightly shifting the optical response to more negative potentials. Charged mutations to the 221 position behaved erratically suggesting interactions with the plasma membrane and/or other amino acids in the VSD. Introduction of bulky amino acids at the V220 position increased the range of the optical response to include hyperpolarizing signals. Combining The V220W mutant with the R217Q mutation resulted in a probe that reduced the depolarizing signal and enhanced the hyperpolarizing signal which may lead to GEVIs that only report neuronal inhibition.

Sensorless Control Technology for PMSG base on the Dead-time Compensation voltage

Directory of Open Access Journals (Sweden)

Yang Li-yong

2015-01-01

Full Text Available In order to improve the speed sensorless-control system of PMSG in low speed performance, this paper introduces a novel Dead-time compensation control method .Mathematical model is established according to the Dead-zone of the influence of the voltage source type inverter output voltage. At the same time, the given value of current regulator output voltage has been fixed based on the established model. Then the stator voltage after compensationed is applied to the flux estimation, which improves the performance of flux estimation. Finally, the position and speed of the rotor is estimated based on Back-Electromotive Force, which has Simple algorithm and good robustness. In order to verify the correctness of theoretical analysis, the experiment was done according to the new control method. The results proved the correctness and feasibility of this control method.

Reduction of Voltage Harmonics for Parallel-operated Inverters

DEFF Research Database (Denmark)

Zhong, Qing-Chang; Blaabjerg, Frede; Guerrero, Josep M.

2011-01-01

The inherent limitations of the conventional droop control scheme have recently been revealed and a robust droop controller to achieve exact proportional load sharing has been proposed. This paper continues the work with a strategy to improve the voltage quality so that the total harmonic...... distortion of the output voltage can be maintained small even when nonlinear loads are connected. Experimental results are provided to verify the analysis and design....

A Low Input Current and Wide Conversion Ratio Buck Regulator with 75% Efficiency for High-Voltage Triboelectric Nanogenerators

Science.gov (United States)

Luo, Li-Chuan; Bao, De-Chun; Yu, Wu-Qi; Zhang, Zhao-Hua; Ren, Tian-Ling

2016-01-01

It is meaningful to research the Triboelectric Nanogenerators (TENG), which can create electricity anywhere and anytime. There are many researches on the structures and materials of TENG to explain the phenomenon that the maximum voltage is stable and the current is increasing. The output voltage of the TENG is high about 180-400 V, and the output current is small about 39 μA, which the electronic devices directly integration of TENG with Li-ion batteries will result in huge energy loss due to the ultrahigh TENG impedance. A novel interface circuit with the high-voltage buck regulator for TENG is introduced firstly in this paper. The interface circuit can transfer the output signal of the TENG into the signal fit to a lithium ion battery. Through the circuit of the buck regulator, the average output voltage is about 4.0 V and the average output current is about 1.12 mA. Further, the reliability and availability for the lithium ion battery and the circuit are discussed. The interface circuit is simulated using the Cadence software and verified through PCB experiment. The buck regulator can achieve 75% efficiency for the High-Voltage TENG. This will lead to a research hot and industrialization applications.

Development of parallel-plate-based MEMS tunable capacitors with linearized capacitance–voltage response and extended tuning range

International Nuclear Information System (INIS)

Shavezipur, M; Nieva, P; Khajepour, A; Hashemi, S M

2010-01-01

This paper presents a design technique that can be used to linearize the capacitance–voltage (C–V) response and extend the tuning range of parallel-plate-based MEMS tunable capacitors beyond that of conventional designs. The proposed technique exploits the curvature of the capacitor's moving electrode which could be induced by either manipulating the stress gradients in the plate's material or using bi-layer structures. The change in curvature generates a nonlinear structural stiffness as the moving electrode undergoes out-of-plane deformation due to the actuation voltage. If the moving plate curvature is tailored such that the capacitance increment is proportional to the voltage increment, then a linear C–V response is obtained. The larger structural resistive force at higher bias voltage also delays the pull-in and increases the maximum tunability of the capacitor. Moreover, for capacitors containing an insulation layer between the two electrodes, the proposed technique completely eliminates the pull-in effect. The experimental data obtained from different capacitors fabricated using PolyMUMPs demonstrate the advantages of this design approach where highly linear C–V responses and tunabilities as high as 1050% were recorded. The design methodology introduced in this paper could be easily extended to for example, capacitive pressure and temperature sensors or infrared detectors to enhance their response characteristics.

Increased voltage photovoltaic cell

Science.gov (United States)

Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

1985-01-01

A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

The Sterilization Effect of Cooperative Treatment of High Voltage Electrostatic Field and Variable Frequency Pulsed Electromagnetic Field on Heterotrophic Bacteria in Circulating Cooling Water

Science.gov (United States)

Gao, Xuetong; Liu, Zhian; Zhao, Judong

2018-01-01

Compared to other treatment of industrial circulating cooling water in the field of industrial water treatment, high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization technology, an advanced technology, is widely used because of its special characteristics--low energy consumption, nonpoisonous and environmentally friendly. In order to get a better cooling water sterilization effect under the premise of not polluting the environment, some experiments about sterilization of heterotrophic bacteria in industrial circulating cooling water by cooperative treatment of high voltage electrostatic field and variable frequency pulsed electromagnetic field were carried out. The comparison experiment on the sterilization effect of high-voltage electrostatic field and variable frequency pulsed electromagnetic field co-sterilization on heterotrophic bacteria in industrial circulating cooling water was carried out by change electric field strength and pulse frequency. The results show that the bactericidal rate is selective to the frequency and output voltage, and the heterotrophic bacterium can only kill under the condition of sweep frequency range and output voltage. When the voltage of the high voltage power supply is 4000V, the pulse frequency is 1000Hz and the water temperature is 30°C, the sterilization rate is 48.7%, the sterilization rate is over 90%. Results of this study have important guiding significance for future application of magnetic field sterilization.

Power conditioning using dynamic voltage restorers under different voltage sag types.

Science.gov (United States)

Saeed, Ahmed M; Abdel Aleem, Shady H E; Ibrahim, Ahmed M; Balci, Murat E; El-Zahab, Essam E A

2016-01-01

Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

The active control strategy on the output power for photovoltaic-storage systems based on extended PQ-QV-PV Node

Science.gov (United States)

Xu, Chen; Zhou, Bao-Rong; Zhai, Jian-Wei; Zhang, Yong-Jun; Yi, Ying-Qi

2017-05-01

In order to solve the problem of voltage exceeding specified limits and improve the penetration of photovoltaic in distribution network, we can make full use of the active power regulation ability of energy storage(ES) and the reactive power regulation ability of grid-connected photovoltaic inverter to provide support of active power and reactive power for distribution network. A strategy of actively controlling the output power for photovoltaic-storage system based on extended PQ-QV-PV node by analyzing the voltage regulating mechanism of point of commom coupling(PCC) of photovoltaic with energy storage(PVES) by controlling photovoltaic inverter and energy storage. The strategy set a small wave range of voltage to every photovoltaic by making the type of PCC convert among PQ, PV and QV. The simulation results indicate that the active control method can provide a better solution to the problem of voltage exceeding specified limits when photovoltaic is connectted to electric distribution network.

An Integrated Chip High-Voltage Power Receiver for Wireless Biomedical Implants

Directory of Open Access Journals (Sweden)

Vijith Vijayakumaran Nair

2015-06-01

Full Text Available In near-field wireless-powered biomedical implants, the receiver voltage largely overrides the compliance of low-voltage power receiver systems. To limit the induced voltage, generally, low-voltage topologies utilize limiter circuits, voltage clippers or shunt regulators, which are power-inefficient methods. In order to overcome the voltage limitation and improve power efficiency, we propose an integrated chip high-voltage power receiver based on the step down approach. The topology accommodates voltages as high as 30 V and comprises a high-voltage semi-active rectifier, a voltage reference generator and a series regulator. Further, a battery management circuit that enables safe and reliable implant battery charging based on analog control is proposed and realized. The power receiver is fabricated in 0.35-μm high-voltage Bipolar-CMOS-DMOStechnology based on the LOCOS0.35-μm CMOS process. Measurement results indicate 83.5% power conversion efficiency for a rectifier at 2.1 mA load current. The low drop-out regulator based on the current buffer compensation and buffer impedance attenuation scheme operates with low quiescent current, reduces the power consumption and provides good stability. The topology also provides good power supply rejection, which is adequate for the design application. Measurement results indicate regulator output of 4 ± 0.03 V for input from 5 to 30 V and 10 ± 0.05 V output for input from 11 to 30 V with load current 0.01–100 mA. The charger circuit manages the charging of the Li-ion battery through all if the typical stages of the Li-ion battery charging profile.

Ranging and Correlating Sensor Development Program.

Science.gov (United States)

1983-11-01

amp- lifies the induced voltage. The output of the amplifier -. can be level detected to alarm on a minimum value of electrostatically induced voltage...with RC networks such that the S voltage drops of both wires are the same in phase and am- * plitude. When an intruder approaches the pair of wires...bandwidth and the bandwidth of n cascaded networks relative * to the bandwidth of a single network is B/B1 = _l___ and the rise time ratio is the

Control strategy and hardware implementation for DC–DC boost power circuit based on proportional–integral compensator for high voltage application

Directory of Open Access Journals (Sweden)

Sanjeevikumar Padmanaban

2015-06-01

Full Text Available For high-voltage (HV applications, the designers mostly prefer the classical DC–DC boost converter. However, it lacks due to the limitation of the output voltage by the gain transfer ratio, decreased efficiency and its requirement of two sensors for feedback signals, which creates complex control scheme with increased overall cost. Furthermore, the output voltage and efficiency are reduced due to the self-parasitic behavior of power circuit components. To overcome these drawbacks, this manuscript provides, the theoretical development and hardware implementation of DC–DC step-up (boost power converter circuit for obtaining extra output-voltage high-performance. The proposed circuit substantially improves the high output-voltage by voltage-lift technology with a closed loop proportional–integral controller. This complete numerical model of the converter circuit including closed loop P-I controller is developed in simulation (Matlab/Simulink software and the hardware prototype model is implemented with digital signal processor (DSP TMS320F2812. A detailed performance analysis was carried out under both line and load regulation conditions. Numerical simulation and its verification results provided in this paper, prove the good agreement of the circuit with theoretical background.

A digital output accelerometer using MEMS-based piezoelectric accelerometers and arrayed CMOS inverters with satellite capacitors

International Nuclear Information System (INIS)

Kobayashi, T; Okada, H; Maeda, R; Itoh, T; Masuda, T

2011-01-01

The present paper describes the development of a digital output accelerometer composed of microelectromechanical systems (MEMS)-based piezoelectric accelerometers and arrayed complementary metal–oxide–semiconductor (CMOS) inverters accompanied by capacitors. The piezoelectric accelerometers were fabricated from multilayers of Pt/Ti/PZT/Pt/Ti/SiO 2 deposited on silicon-on-insulator (SOI) wafers. The fabricated piezoelectric accelerometers were connected to arrayed CMOS inverters. Each of the CMOS inverters was accompanied by a capacitor with a different capacitance called a 'satellite capacitor'. We have confirmed that the output voltage generated from the piezoelectric accelerometers can vary the output of the CMOS inverters from a high to a low level; the state of the CMOS inverters has turned from the 'off-state' into the 'on-state' when the output voltage of the piezoelectric accelerometers is larger than the threshold voltage of the CMOS inverters. We have also confirmed that the CMOS inverters accompanied by the larger satellite capacitor have become 'on-state' at a lower acceleration. On increasing the acceleration, the number of on-state CMOS inverters has increased. Assuming that the on-state and off-state of CMOS inverters correspond to logic '0' and '1', the present digital output accelerometers have expressed the accelerations of 2.0, 3.0, 5.0, and 5.5 m s −2 as digital outputs of 111, 110, 100, and 000, respectively

Optimal Constant DC Link Voltage Operation of aWave Energy Converter

Directory of Open Access Journals (Sweden)

Mats Leijon

2013-04-01

Full Text Available This article proposes a simple and reliable damping strategy for wave powerfarm operation of small-scale point-absorber converters. The strategy is based on passiverectification onto a constant DC-link, making it very suitable for grid integration of the farm.A complete model of the system has been developed in Matlab Simulink, and uses real sitedata as input. The optimal constant DC-voltage is evaluated as a function of the significantwave height and energy period of the waves. The total energy output of the WEC is derivedfor one year of experimental site data. The energy output is compared for two cases, onewhere the optimal DC-voltage is determined and held constant at half-hour basis throughoutthe year, and one where a selected value of the DC-voltage is kept constant throughout theyear regardless of sea state.

High-Voltage DC-DC Converter Topology for PV Energy Utilization - Investigation and Implementation

DEFF Research Database (Denmark)

Sanjeevikumar, Padmanaban; Blaabjerg, Frede; Wheeler, Patrick

2017-01-01

This paper exploited the utilization of photovoltaic (PV) energy system with high-voltage (HV) output DC-DC converter. Classical boost converters are used for both renewable energy integration and HV applications, but limited by reducing output/efficiency in performance. Moreover, as parasitic...... elements suppress the power transfer ratio, converter needs to maximize the PV energy utilization. This investigation study focused to include additional parasitic elements (voltage-lift technique) to a standard DC-DC buck converter and to overcome all the above drawbacks to maximize the PV power...

Stabilization of Voltage Parameters of Induction Generator Excited by a Voltage Inverter

Directory of Open Access Journals (Sweden)

Padalko D.A.

2017-12-01

Full Text Available The article reveals the operational aspects of induction generator. Methods for stabilization of induction generator (IG parameters under inverter excitation are investigated. The study was carried out using mathematical description and simulation modeling in MATLAB Simulink. The paper provides analysis of causes of generated voltage amplitude and frequency displacement when the loading condition and the rate vary. Due to the parametric resonance nature of IG self-excitation, the author introduces the expression that allows estimating the capacitor capacitance required to maintain the generation process, depending on the rotor speed of electric machine, load nature and rate. Based on the studies, it was proved that it is possible to stabilize the IG voltage parameters by maintaining the magnetizing circuit inductance Lm at the constant level., and realizing a control law close to U/f = const. The study proves that using the inverter together with the voltage regulator allows ensuring the quality of electricity corresponding to modern standards. The necessity of problem solving of the required quality of the voltage by the harmonic component for the exciter - inverter with PWM is shown. The prospects of the power generation system based on induction machine (IM with a semiconductor frequency converter, which serves as an adjustable supplier of capacitive current for IM for autonomous objects, are substantiated. The use of semiconductor frequency converters makes it possible to provide high stability of the output voltage parameters and good speed of the mechatronic generation system with an asynchronous machine.

A Wide-Range Tunable Level-Keeper Using Vertical Metal-Oxide-Semiconductor Field-Effect Transistors for Current-Reuse Systems

Science.gov (United States)

Tanoi, Satoru; Endoh, Tetsuo

2012-04-01

A wide-range tunable level-keeper using vertical metal-oxide-semiconductor field-effect transistors (MOSFETs) is proposed for current-reuse analog systems. The design keys for widening tunable range of the operation are a two-path feed-back and a vertical MOSFET with back-bias-effect free. The proposed circuit with the vertical MOSFETs shows the 1.23-V tunable-range of the input level with the 2.4-V internal-supply voltage (VDD) in the simulation. This tunable-range of the proposed circuit is 4.7 times wider than that of the conventional. The achieved current efficiency of the proposed level-keeper is 66% at the 1.2-V output with the 2.4-V VDD. This efficiency of the proposed circuit is twice higher than that of the traditional voltage down converter.

Innovation of High Voltage Supply Adjustment Device on Diagnostic X-Ray Machine

International Nuclear Information System (INIS)

Sujatno; Wiranto Budi Santoso

2010-01-01

Innovation of high voltage supply adjustment device on diagnostic x-ray machine has been carried out. The innovation is conducted by utilizing an electronic circuit as a high voltage adjustment device. Usually a diagnostic x-ray machine utilizes a transformer or an auto-transformer as a high voltage supply adjustment device. A high power diagnostic x-ray machine needs a high power transformer which has big physical dimension. Therefore a box control where the transformer is located has to have big physical dimension. Besides, the price of the transformer is expensive and hardly found in local markets. In this innovation, the transformer is replaced by an electronic circuit. The main component of the electronic circuit is Triac BTA-40. As adjustment device, the triac is controlled by a variable resistor which is coupled by a stepper motor. A step movement of stepper motor varies a value of resistor. The resistor value determines the triac gate voltage. Furthermore the triac will open according to the value of electrical current flowing to the gate. When the gate is open, electrical voltage and current will flow from cathode to anode of the triac. The value of these electrical voltage and current depend on gate open condition. Then this triac output voltage is feed to diagnostic x-ray machine high voltage supply. Therefore the high voltage value of diagnostic x-ray machine is adjusted by the output voltage of the electronic circuit. By using this electronic circuit, the physical dimension of diagnostic x-ray machine box control and the price of the equipment can be reduced. (author)

Characterization of a pulsed mode high voltage power supply for nuclear detectors

International Nuclear Information System (INIS)

Ghazali, A B; Ahmad, T S; Abdullah, N A

2013-01-01

This paper discusses the characterization of a pulsed mode high voltage power supply (HVPS) using LT1073 chip. The pulsed modulated signal generated from this chip is amplified using a step-up ferrite core transformer of 1:20 turn ratio and then further multiplied and converted into DC high voltage output using a diode-capacitor arrangement. The circuit is powered by a 9V alkaline battery but regulated at 5V supply. It was found that the output for this setup is 520V, 87 μA with 10% load regulation. This output is suitable to operate a pancake-type GM detector, typically model LND 7317 where the plateau is from 475V to 675V. It was also found that when a β-source with intensity of 120 cps is used, the power consumption of the circuit is 5 V, 10.1 mA only. When the battery was left 'on' for 40 hours continuously, the battery's voltage has dropped to 6.9V, meaning that the 5V supply as well as 520V output is still maintained. It is noted that the minimum output voltage of 475V has reached when the regulated supply has reduced to 4.6V and consequently the 9V battery dropped to 6.5V, and this had happened after approximately 3 days of continuous operation. The power efficiency for this circuitry was found to be 89.5%. This result has far better in performance since the commercial portable equipment of this type has normally specified that not less than 8 hours continuous operation only. On the circuit design for this power supply, it was found that the enveloped frequency is 133 Hz with approximately 50% duty cycle. The modulated frequency during 'on' state was found to be 256 KHz in which the majority of power consumption is required.

Design, experiments and simulation of voltage transformers on the basis of a differential input D-dot sensor.

Science.gov (United States)

Wang, Jingang; Gao, Can; Yang, Jie

2014-07-17

Currently available traditional electromagnetic voltage sensors fail to meet the measurement requirements of the smart grid, because of low accuracy in the static and dynamic ranges and the occurrence of ferromagnetic resonance attributed to overvoltage and output short circuit. This work develops a new non-contact high-bandwidth voltage measurement system for power equipment. This system aims at the miniaturization and non-contact measurement of the smart grid. After traditional D-dot voltage probe analysis, an improved method is proposed. For the sensor to work in a self-integrating pattern, the differential input pattern is adopted for circuit design, and grounding is removed. To prove the structure design, circuit component parameters, and insulation characteristics, Ansoft Maxwell software is used for the simulation. Moreover, the new probe was tested on a 10 kV high-voltage test platform for steady-state error and transient behavior. Experimental results ascertain that the root mean square values of measured voltage are precise and that the phase error is small. The D-dot voltage sensor not only meets the requirement of high accuracy but also exhibits satisfactory transient response. This sensor can meet the intelligence, miniaturization, and convenience requirements of the smart grid.

Number-to-voltage converter on commutated condensers

International Nuclear Information System (INIS)

Grekhov, Yu.N.

1975-01-01

A code-voltage converter using precision voltage dividers based on commutated capacitors [1] is described which is distinguished by the absence of precision elements. Each digit includes eight field-effect transistors in two 1KT682 microcircuit assemblies and three microcapacitors with a conventional unstable capacitance 6200 pF +- 50%. The converter has a speed of response that is not inferior to that of converters based on R-2R matrices, while in time stability of the characteristics, low interference level, and low output impedance it is superior to such converters

High-voltage nanosecond pulse shaper

International Nuclear Information System (INIS)

Kapishnikov, N.K.; Muratov, V.M.; Shatanov, A.A.

1987-01-01

A high-voltage pulse shaper with an output of up to 250 kV, a base duration of ∼ 10 nsec, and a repetition frequency of 50 pulses/sec is described. The described high-voltage nanosecond pulse shaper is designed for one-orbit extraction of an electron beam from a betatron. A diagram of the pulse shaper, which employs a single-stage generator is shown. The shaping element is a low-inductance capacitor bank of series-parallel KVI-3 (2200 pF at 10 kV) or K15-10 (4700 pF at 31.5 kV) disk ceramic capacitors. Four capacitors are connected in parallel and up to 25 are connected in series

Characteristics of a new non-invasive X-ray output analyzer

International Nuclear Information System (INIS)

Shinohara, Fuminori; Ishikawa, Mitsuo; Miyazaki, Shigeru

2002-01-01

The X-ray systems study group used the Victoreen NERO mAx model 8000, a new non-invasive X-ray output analyzer, to measure the tube voltage, tube voltage waveform, tube current, and irradiation time for conditions corresponding to general radiography and mammography. The measurement results were then compared with those obtained using a conventional invasive measuring instrument. The peak values of the tube voltage measured by the NERO mAx and the invasive measuring instrument were compared. The NERO mAx had a good measurement error range of -1.2 to +0.9 kV. For tube current measurement by the NERO mAx, the maximum error for general radiography conditions was +11 mA and that for mammography conditions was +6 mA. For irradiation time measurement, the value for general radiography conditions was slightly greater and the value for mammography conditions was slightly less than the corresponding values obtained by the invasive measuring instrument. If radiation quality is changed during measurement of the characteristics, measurement values change. Since the NERO mAx incorporates two types of X-ray detectors, it shows good measurement reproducibility. The NERO mAx has been shown to have suitable characteristics for use as a measuring instrument for constancy tests. In the future, constancy tests should be used to quantitatively control the factors determining clinical image quality. (author)

A low-voltage Op Amp with rail-to-rail constant-gm input stage and a class AB rail-to-rail output stage

NARCIS (Netherlands)

Botma, J.H.; Wassenaar, R.F.; Wiegerink, Remco J.

1993-01-01

In this paper a low-voltage two-stage Op Amp is presented. The Op Amp features rail-to-rail operation and has an @put stage with a constant transconductance (%) over the entire common-mode input range. The input stage consists of an n- and a PMOS differential pair connected in parallel. The constant

Frequency to Voltage Converter Analog Front-End Prototype

Science.gov (United States)

Mata, Carlos; Raines, Matthew

2012-01-01

The frequency to voltage converter analog front end evaluation prototype (F2V AFE) is an evaluation board designed for comparison of different methods of accurately extracting the frequency of a sinusoidal input signal. A configurable input stage is routed to one or several of five separate, configurable filtering circuits, and then to a configurable output stage. Amplifier selection and gain, filter corner frequencies, and comparator hysteresis and voltage reference are all easily configurable through the use of jumpers and potentiometers.

Containment and Consensus-based Distributed Coordination Control for Voltage Bound and Reactive Power Sharing in AC Microgrid

DEFF Research Database (Denmark)

Han, Renke; Meng, Lexuan; Ferrari-Trecate, Giancarlo

2017-01-01

This paper offers a highly flexible and reliable control strategy to achieve voltage bounded regulation and accurate reactive power sharing coordinately in AC Micro-Grids. A containment and consensus-based distributed coordination controller is proposed, by which each output voltage magnitude can...... be bounded within a reasonable range and the accurate reactive power sharing among distributed generators can be also achieved. Combined with the two proposed controllers and electrical part of the AC Micro-Grid, a small signal model is fully developed to analyze the sensitivity of different control...... parameters. The effectiveness of the proposed controller in case of load variation, communication failure, plug-and-play capability are verified by the experimental setup as an islanded Micro-Grid....

A High-Voltage Low-Power Switched-Capacitor DC-DC Converter Based on GaN and SiC Devices for LED Drivers

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

2018-01-01

Previous research on switched-capacitor DC-DC converters has focused on low-voltage and/or high-power ranges where the efficiencies are dominated by conduction loss. Switched-capacitor DC-DC converters at high-voltage (> 100 V) low-power (high efficiency and high power density...... are anticipated to emerge. This paper presents a switched-capacitor converter with an input voltage up to 380 V (compatible with rectified European mains) and a maximum output power of 10 W. GaN switches and SiC diodes are analytically compared and actively combined to properly address the challenges at high......-voltage low-current levels, where switching loss becomes significant. Further trade-off between conduction loss and switching loss is experimentally optimized with switching frequencies. Three variant designs of the proposed converter are implemented, and the trade-off between the efficiency and the power...

Time-division-multiplex control scheme for voltage multiplier rectifiers

Directory of Open Access Journals (Sweden)

Bin-Han Liu

2017-03-01

Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

Regulation of the output power at the resonant converter

Energy Technology Data Exchange (ETDEWEB)

Stefanov, Goce G.; Sarac, Vasilija J. [University Goce Delecev-Stip, Faculty of Electrical Engineering, Radovis (Macedonia, The Former Yugoslav Republic of); Karadzinov, Ljupco V., E-mail: goce.stefanov@ugd.edu.mk [University Kiril and Methodyus-Skopje, FEIT Skopje(Macedonia, The Former Yugoslav Republic of)

2011-07-01

In this paper a method for regulating an alternating current voltage source with pair of IGBT transistor’s modules, in a full bridge configuration with series resonant converter is given. With the developed method a solution is obtained which can regulate the phase difference between output voltage and current through the inductor, in order to maintain maximum output power. Control electronic via feedback signals regulates the energy transfer to the tank by changing the pulse width of signals which are used as inputs to the gates of the IGBTs. By increasing or decreasing the pulse width transmitted to the various gates of the IGBT the energy transfer to the tank is increased or decreased . PowerSim simulations program is used for development of controlling methodology. Developed method is practically implemented in a prototype of the device for phase control of resonant converter with variable the resonant load. Key words: pulse width method, phase regulation , power converter.

Artificial Neural Network Application for Power Transfer Capability and Voltage Calculations in Multi-Area Power System

Directory of Open Access Journals (Sweden)

Palukuru NAGENDRA

2010-12-01

Full Text Available In this study, the use of artificial neural network (ANN based model, multi-layer perceptron (MLP network, to compute the transfer capabilities in a multi-area power system was explored. The input for the ANN is load status and the outputs are the transfer capability among the system areas, voltage magnitudes and voltage angles at concerned buses of the areas under consideration. The repeated power flow (RPF method is used in this paper for calculating the power transfer capability, voltage magnitudes and voltage angles necessary for the generation of input-output patterns for training the proposed MLP neural network. Preliminary investigations on a three area 30-bus system reveal that the proposed model is computationally faster than the conventional method.

Driving Pressure Influence in Voltage Maps Measurement Process Using Advanced Pneumatic Mapping Probe

Directory of Open Access Journals (Sweden)

Marek Kukucka

2016-01-01

Full Text Available Our paper deals with the method of the voltage-impedance map measurement process as a method useful for the electric mapping of human skin. The area of research extends from the basic research to its practical application in acupuncture skin mapping and acupuncture point localization and visualization. The problem of sufficient skin coverage and electrical contact with measuring electrodes is solved by the conventional mechanical telescopic electrodes and by the pneumatic matrix electrode probe. A 2D or 3D voltage-impedance map of skin is an output of the measuring, interpretation and evaluation process. New pneumatic construction of measuring probe was implemented to achieve a better coverage of specified skin area and get a reduced force range of the touching electrodes allowing the steady contact of the skin-electrode. A skin contact is related to the driving pressure of touching electrodes. Our paper offers experimentally measured results, voltage maps of skin on specific areas, selected measured and described acupuncture points and their applications in electro-acupuncture.

Design and construction of constant voltage and current regulated source with proper characteristics to be used in electronics laboratory designs

International Nuclear Information System (INIS)

Peon A, R.

1978-01-01

A regulated direct current feeding source was designed for the Nuclear Energy National Institute Electronics Labortory, with the following characteristics: a) voltage input 105-130V a.c. 50-60 Hz; b) voltage output 0.40 V d.c.; c) output current 0-2 Amp d.c.; d) load regulation 0.001%; e) line regulation 0.001%; f) ripple and noise 200 μ Vpp; g) temperature interval 3-60 0 C; h) stability 0.5%; i) output impedance as voltage source 0.01 ohms; j) transient response 50 μ seg. Besides of operating normally, that is as voltage source or current-source through the front controls, the source can be used and interconnected with one or other compatible sources (autoseries, autoparallel and programmed reference). The source will cost 70,000 pesos approximately. (author)

IBM-PC based high voltage controller [Paper No.: L7

International Nuclear Information System (INIS)

Mondal, N.K.; Kalmani, S.D.

1993-01-01

A simple IBM-PC/XT based high voltage controller is designed for C.A.E.N. high voltage supply unit, which is being used for testing the prototype detector for future accelerator experiment. The high voltage output of the supply unit can be remotely programmed. The V-set Lemo connectors at the rear panel provides the remote control facility. Similarly V-mon and I-mon can be used for remotely monitoring the voltage set and the current drawn from the supply unit. The controller described here sets the high voltage through V-set and monitors the voltage set, through V-mon at a pre-determined time interval. The monitoring is a background job and is done as an interrupt service routine of IRQ3. A simple menu driven software package used is written in Q-Basic and MASM. (author). 1 fig

An approach for high voltage power supply system for HCAL of LHCb experiment

International Nuclear Information System (INIS)

Cimpean, A.; Dumitru, D.; Kluger, A.; Magureanu, C.; Tarta, D.; Coca, C.; Orlandea, M.; Popescu, S.

2003-01-01

The main aim of the calorimeter system of the LHCb (Large Hadron Collider Beauty) experiment dedicated to precision measurements of CP violation and rare phenomena is to provide identification of the electrons, hadrons and photons, for the level-0 trigger and offline analysis with measurements of position and energy. The system consists in a scintillator pad/preshower (SPD/PS) detector, an electromagnetic calorimeter (ECAL) and a hadron calorimeter (HCAL), all the sub-detectors having a similar technology with scintillating tiles as active material and being read out via wavelength-shifting fibers and with an identical readout electronics for ECAL and HCAL and similar electronics for the PS. During 1997-1999 a computer controlled High Voltage (HV) distribution scheme was developed by Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) group and used to supply the PMTs of half HCAL prototype during the beam tests (1998-2000). This scheme consisted of three parts: 1) a control box which includes low voltage power supply, the RS232 interface to a PC and three modules of high voltage power supply; 2) two types of multichannel HV distributors with an individual voltage setting; 3) a software package to control all settings and refresh them periodically. Based on the acquired experience, a new design for a High Voltage Power Supply (HVPS) which satisfies the LHCb requirements has been developed for PMTs of the hadron calorimeter. The demands of this system are simplicity and low cost. This HVPS with multiple outputs (HV for photocathode and D1 - D4 dynodes) is destined to supply, with the same high voltage, groups of PMTs sorted by similar characteristics as gain and sensitivity. Because of the high rates (∼ 40 MHz) supported by PMTs, booster voltage sources are necessary to supply current for the last 4 dynodes. The box has 5 HV power supplies for photocathodes and the last 4 dynodes, each HV power supply being followed by a 4 channel

Analysis of Voltage Forming Methods for Multiphase Inverters

Directory of Open Access Journals (Sweden)

Tadas Lipinskis

2013-05-01

Full Text Available The article discusses advantages of the multiphase AC induction motor over three or less phase motors. It presents possible stator winding configurations for a multiphase induction motor. Various fault control strategies were reviewed for phases feeding the motor. The authors propose a method for quality evaluation of voltage forming algorithm in the inverter. Simulation of a six-phase voltage source inverter, voltage in which is formed using a simple SPWM control algorithm, was performed in Matlab Simulink. Simulation results were evaluated using the proposed method. Inverter’s power stage was powered by 400 V DC source. The spectrum of output currents was analysed and the magnitude of the main frequency component was at least 12 times greater than the next biggest-magnitude component. The value of rectified inverter voltage was 373 V.Article in Lithuanian

The Design of Operational Amplifier for Low Voltage and Low Current Sound Energy Harvesting System

Science.gov (United States)

Fang, Liew Hui; Rahim, Rosemizi Bin Abd; Isa, Muzamir; Idris Syed Hassan, Syed; Ismail, Baharuddin Bin

2018-03-01

The objective of this paper is to design a combination of an operational amplifier (op-amp) with a rectifier used in an alternate current (ac) to direct current (dc) power conversion. The op-amp was designed to specifically work at low voltage and low current for a sound energy harvesting system. The goal of the op-amp design with adjustable gain was to control output voltage based on the objectives of the experiment conducted. The op-amp was designed for minimum power dissipation performance, with the means of increasing the output current when receiving a large amount of load. The harvesting circuits which designed further improved the power output efficiency by shortening the fully charged time needed by a supercapacitor bank. It can fulfil the long-time power demands for low power device. Typically, a small amount of energy sources were converted to electricity and stored in the supercapacitor bank, which was built by 10 pieces of capacitors with 0.22 F each, arranged in parallel connection. The highest capacitance was chosen based on the characteristic that have the longest discharging time to support the applications of a supercapacitor bank. Testing results show that the op-amp can boost the low input ac voltage (∼3.89 V) to high output dc voltage (5.0 V) with output current of 30 mA and stored the electrical energy in a big supercapacitor bank having a total of 2.2 F, effectively. The measured results agree well with the calculated results.

A Hybrid, Current-Source/Voltage-Source Power Inverter Circuit

DEFF Research Database (Denmark)

Trzynadlowski, Andrzej M.; Patriciu, Niculina; Blaabjerg, Frede

2001-01-01

A combination of a large current-source inverter and a small voltage-source inverter circuits is analyzed. The resultant hybrid inverter inherits certain operating advantages from both the constituent converters. In comparison with the popular voltage-source inverter, these advantages include...... reduced switching losses, improved quality of output current waveforms, and faster dynamic response to current control commands. Description of operating principles and characteristics of the hybrid inverter is illustrated with results of experimental investigation of a laboratory model....

Sigma-Delta Voltage to Frequency Converter With Phase Modulation Possibility

OpenAIRE

STORK, Milan

2014-01-01

Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. There are two common VFC architectures: the current steering multivibrator and the charge-balance VFC. For higher linearity, the charge-balancing method is preferred. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge balanced VFC or "sigma delta" (S-D) VFC is used when output pulses are synchroni...

Design and Implementation of a High Efficiency, Low Component Voltage Stress, Single-Switch High Step-Up Voltage Converter for Vehicular Green Energy Systems

Directory of Open Access Journals (Sweden)

Yu-En Wu

2016-09-01

Full Text Available In this study, a novel, non-isolated, cascade-type, single-switch, high step-up DC/DC converter was developed for green energy systems. An integrated coupled inductor and voltage lift circuit were applied to simplify the converter structure and satisfy the requirements of high efficiency and high voltage gain ratios. In addition, the proposed structure is controllable with a single switch, which effectively reduces the circuit cost and simplifies the control circuit. With the leakage inductor energy recovery function and active voltage clamp characteristics being present, the circuit yields optimizable conversion efficiency and low component voltage stress. After the operating principles of the proposed structure and characteristics of a steady-state circuit were analyzed, a converter prototype with 450 W, 40 V of input voltage, 400 V of output voltage, and 95% operating efficiency was fabricated. The Renesas MCU RX62T was employed to control the circuits. Experimental results were analyzed to validate the feasibility and effectiveness of the proposed system.

Flexible operation of parallel grid-connecting converters under unbalanced grid voltage

DEFF Research Database (Denmark)

Lu, Jinghang; Savaghebi, Mehdi; Guerrero, Josep M.

2017-01-01

-link voltage ripple, and overloading. Moreover, under grid voltage unbalance, the active power delivery ability is decreased due to the converter's current rating limitation. In this paper, a thorough study on the current limitation of the grid-connecting converter under grid voltage unbalance is conducted....... In addition, based on the principle that total output active power should be oscillation free, a coordinated control strategy is proposed for the parallel grid-connecting converters. The case study has been conducted to demonstrate the effectiveness of this proposed control strategy....

Power-supply system for high-voltage electron guns with grid control

International Nuclear Information System (INIS)

Grigorev, Y.V.

1985-01-01

A power-supply system for electron guns with grid control is described which consists of a source of accelerating voltage between 20 and 180 kV with a current of 100 mA and a control circuit for an electron gun that contains a pulse generator having an output voltage of up to 5 kV for pulse durations of 2, 10, 50 and 90 microseconds. The output pulses of the generator are synchronized with a certain phase of the cathode heater current of the gun, and they can be repeated at a frequency between 100 and 0.4 Hz. The system is reliable and resistant to the overloads associated with breakdowns in the gun

Micro controller application as x-ray machine's high voltage controller

International Nuclear Information System (INIS)

Wiranto Budi Santoso; Beny Syawaludin

2010-01-01

The micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive the stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-B051 compiler. The test results show that the stepper motor could rotate according to an input value. (author)

Technical feasibility study of Voltage Optimization Unit

DEFF Research Database (Denmark)

Hu, Junjie; Marinelli, Mattia; Coppo, Massimiliano

This report provides an analysis on the benefits of a transformer with on load tap chang-ers on each phase that can be applied in the distribution system to accommodate more renewable generations such as photovoltaic power. The main purpose of this research is to verify whether power distribution...... are used as load basics for the analysis. In term of PV genera-tion profiles, a realistic PV output power is assumed. Four relevant indicies such as phase neutral voltage, netural potential voltage, unbalanced factor (VUF), and power losses are evaluated in the present study. The simulation tests include...

A novel on-chip high to low voltage power conversion circuit

International Nuclear Information System (INIS)

Wang Hui; Wang Songlin; Mou Zaixin; Guo Baolong; Lai Xinquan; Ye Qiang; Li Xianrui

2009-01-01

A novel power supply transform technique for high voltage IC based on the TSMC 0.6 μm BCD process is achieved. An adjustable bandgap voltage reference is presented which is different from the traditional power supply transform technique. It can be used as an internal power supply for high voltage IC by using the push-pull output stage to enhance its load capability. High-order temperature compensated circuit is designed to ensure the precision of the reference. Only 0.01 mm 2 area is occupied using this novel power supply technique. Compared with traditional technique, 50% of the area is saved, 40% quiescent power loss is decreased, and the temperature coefficient of the reference is only 4.48 ppm/deg. C. Compared with the traditional LDO (low dropout) regulator, this power conversion architecture does not need external output capacitance and decreases the chip-pin and external components, so the PCB area and design cost are also decreased. The testing results show that this circuit works well.

A novel on-chip high to low voltage power conversion circuit

Energy Technology Data Exchange (ETDEWEB)

Wang Hui; Wang Songlin; Mou Zaixin; Guo Baolong [Institute of Mechano-electronic Engineering, Xidian University, Xi' an 71007 (China); Lai Xinquan; Ye Qiang; Li Xianrui, E-mail: whui94@126.co [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China)

2009-03-15

A novel power supply transform technique for high voltage IC based on the TSMC 0.6 mum BCD process is achieved. An adjustable bandgap voltage reference is presented which is different from the traditional power supply transform technique. It can be used as an internal power supply for high voltage IC by using the push-pull output stage to enhance its load capability. High-order temperature compensated circuit is designed to ensure the precision of the reference. Only 0.01 mm{sup 2} area is occupied using this novel power supply technique. Compared with traditional technique, 50% of the area is saved, 40% quiescent power loss is decreased, and the temperature coefficient of the reference is only 4.48 ppm/deg. C. Compared with the traditional LDO (low dropout) regulator, this power conversion architecture does not need external output capacitance and decreases the chip-pin and external components, so the PCB area and design cost are also decreased. The testing results show that this circuit works well.

Non-linear control of the output stage of a solar microinverter

Science.gov (United States)

Lopez-Santos, Oswaldo; Garcia, Germain; Martinez-Salamero, Luis; Avila-Martinez, Juan C.; Seguier, Lionel

2017-01-01

This paper presents a proposal to control the output stage of a two-stage solar microinverter to inject real power into the grid. The input stage of the microinverter is used to extract the maximum available power of a photovoltaic module enforcing a power source behavior in the DC-link to feed the output stage. The work here reported is devoted to control a grid-connected power source inverter with a high power quality level at the grid side ensuring the power balance of the microinverter regulating the voltage of the DC-link. The proposed control is composed of a sinusoidal current reference generator and a cascade type controller composed by a current tracking loop and a voltage regulation loop. The current reference is obtained using a synchronized generator based on phase locked loop (PLL) which gives the shape, the frequency and phase of the current signal. The amplitude of the reference is obtained from a simple controller regulating the DC-link voltage. The tracking of the current reference is accomplished by means of a first-order sliding mode control law. The solution takes advantage of the rapidity and inherent robustness of the sliding mode current controller allowing a robust behavior in the regulation of the DC-link using a simple linear controller. The analytical expression to determine the power quality indicators of the micro-inverter's output is theoretically solved giving expressions relating the converter parameters. The theoretical approach is validated using simulation and experimental results.

Technological Aspects: High Voltage

CERN Document Server

Faircloth, D.C.

2013-12-16

This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.

Flying capacitor resonant pole inverter applying five voltage levels

NARCIS (Netherlands)

Settels, S.J.

2017-01-01

Industrial applications, e.g. semiconductor manufacturing equipment, require power amplifiers providing high power with high precision and bandwidth. Due to limitations in system infrastructure, increasing voltage is favorable to increasing current to generate more output power. This research

Power supply and impedance matching to drive technological radio-frequency plasmas with customized voltage waveforms.

Science.gov (United States)

Franek, James; Brandt, Steven; Berger, Birk; Liese, Martin; Barthel, Matthias; Schüngel, Edmund; Schulze, Julian

2015-05-01

We present a novel radio-frequency (RF) power supply and impedance matching to drive technological plasmas with customized voltage waveforms. It is based on a system of phase-locked RF generators that output single frequency voltage waveforms corresponding to multiple consecutive harmonics of a fundamental frequency. These signals are matched individually and combined to drive a RF plasma. Electrical filters are used to prevent parasitic interactions between the matching branches. By adjusting the harmonics' phases and voltage amplitudes individually, any voltage waveform can be approximated as a customized finite Fourier series. This RF supply system is easily adaptable to any technological plasma for industrial applications and allows the commercial utilization of process optimization based on voltage waveform tailoring for the first time. Here, this system is tested on a capacitive discharge based on three consecutive harmonics of 13.56 MHz. According to the Electrical Asymmetry Effect, tuning the phases between the applied harmonics results in an electrical control of the DC self-bias and the mean ion energy at almost constant ion flux. A comparison with the reference case of an electrically asymmetric dual-frequency discharge reveals that the control range of the mean ion energy can be significantly enlarged by using more than two consecutive harmonics.

Cell voltage versus electrode potential range in aqueous supercapacitors

OpenAIRE

Dai, Zengxin; Peng, Chuang; Chae, Jung Hoon; Ng, Kok Chiang; Chen, George Z.

2015-01-01

Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the c...

PV source based high voltage gain current fed converter

Science.gov (United States)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Adaptive Sliding Mode Control of MEMS AC Voltage Reference Source

Directory of Open Access Journals (Sweden)

Ehsan Ranjbar

2017-01-01

Full Text Available The accuracy of physical parameters of a tunable MEMS capacitor, as the major part of MEMS AC voltage reference, is of great importance to achieve an accurate output voltage free of the malfunctioning noise and disturbance. Even though strenuous endeavors are made to fabricate MEMS tunable capacitors with desiderated accurate physical characteristics and ameliorate exactness of physical parameters’ values, parametric uncertainties ineluctably emerge in fabrication process attributable to imperfections in micromachining process. First off, this paper considers applying an adaptive sliding mode controller design in the MEMS AC voltage reference source so that it is capable of giving off a well-regulated output voltage in defiance of jumbling parametric uncertainties in the plant dynamics and also aggravating external disturbance imposed on the system. Secondly, it puts an investigatory comparison with the designed model reference adaptive controller and the pole-placement state feedback one into one’s prospective. Not only does the tuned adaptive sliding mode controller show remarkable robustness against slow parameter variation and external disturbance being compared to the pole-placement state feedback one, but also it immensely gets robust against the external disturbance in comparison with the conventional adaptive controller. The simulation results are promising.

An Improved Droop Control Method for DC Microgrids Based on Low Bandwidth Communication with DC Bus Voltage Restoration and Enhanced Current Sharing Accuracy

DEFF Research Database (Denmark)

Lu, Xiaonan; Guerrero, Josep M.; Sun, Kai

2014-01-01

Droop control is the basic control method for load current sharing in dc microgrid applications. The conventional dc droop control method is realized by linearly reducing the dc output voltage as the output current increases. This method has two limitations. First, with the consideration of line...... resistance in a droop-controlled dc microgrid, since the output voltage of each converter cannot be exactly the same, the output current sharing accuracy is degraded. Second, the DC bus voltage deviation increases with the load due to the droop action. In this paper, in order to improve the performance......, and the LBC system is only used for changing the values of the dc voltage and current. Hence, a decentralized control scheme is accomplished. The simulation test based on Matlab/Simulink and the experimental validation based on a 2×2.2 kW prototype were implemented to demonstrate the proposed approach....

Design of a CMOS temperature sensor with current output

NARCIS (Netherlands)

Kolling, A.; Kölling, Arjan; Bak, Frans; Bergveld, Piet; Seevinck, E.; Seevinck, Evert

1990-01-01

In this paper a CMOS temperature-to-current converter is presented of which the output current is the difference between a PTC current and an NTC current. The PTC current is derived from a PTAT cell, while the NTC current is derived from a threshold voltage reference source. It is shown that this

Design, Experiments and Simulation of Voltage Transformers on the Basis of a Differential Input D-dot Sensor

Directory of Open Access Journals (Sweden)

Jingang Wang

2014-07-01

Full Text Available Currently available traditional electromagnetic voltage sensors fail to meet the measurement requirements of the smart grid, because of low accuracy in the static and dynamic ranges and the occurrence of ferromagnetic resonance attributed to overvoltage and output short circuit. This work develops a new non-contact high-bandwidth voltage measurement system for power equipment. This system aims at the miniaturization and non-contact measurement of the smart grid. After traditional D-dot voltage probe analysis, an improved method is proposed. For the sensor to work in a self-integrating pattern, the differential input pattern is adopted for circuit design, and grounding is removed. To prove the structure design, circuit component parameters, and insulation characteristics, Ansoft Maxwell software is used for the simulation. Moreover, the new probe was tested on a 10 kV high-voltage test platform for steady-state error and transient behavior. Experimental results ascertain that the root mean square values of measured voltage are precise and that the phase error is small. The D-dot voltage sensor not only meets the requirement of high accuracy but also exhibits satisfactory transient response. This sensor can meet the intelligence, miniaturization, and convenience requirements of the smart grid.

Harmonic Analysis and Mitigation of Low- Frequency Switching Voltage Source Inverter with Auxiliary VSI

DEFF Research Database (Denmark)

Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

2018-01-01

The output currents of high-power Voltage Source Inverters (VSIs) are distorted by the switching harmonics and the background harmonics in the grid voltage. This paper presents an active harmonic filtering scheme for high-power, low-frequency switching VSIs with an additional auxiliary VSI. In th...

Digitally Programmable High-Q Voltage Mode Universal Filter

Directory of Open Access Journals (Sweden)

D. Singh

2013-12-01

Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

Technological Aspects: High Voltage

International Nuclear Information System (INIS)

Faircloth, D C

2013-01-01

This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered. (author)

Means and method for controlling the neutron output of a neutron generator tube

International Nuclear Information System (INIS)

Langford, O.M.; Peelman, H.E.

1980-01-01

A gas filled neutron tube in a nuclear well logging tool has a target an ion source voltage and a replenisher connected to ground. A negative high voltage is applied to the target by a power supply also providing a target current corresponding to the neutron output of the neutron generator tube. A constant current source provides a constant current. A network receiving the target current and the constant current provides a portion of the constant current as a replenisher current which is applied to the replenisher in a neutron generating tube. The network controls the magnitude of the replenisher current in accordance with the target current so as to control the neutron output of the neutron generating tube. (auth)

Digital Control of a High Voltage (2.5 kV) Bidirectional Flyback DC-DC Converter for Driving a Capacitive Incremental Actuator

DEFF Research Database (Denmark)

Thummala, Prasanth; Maksimovic, Dragan; Zhang, Zhe

2016-01-01

This paper presents a digital control technique to achieve valley switching in a bidirectional flyback converter used to drive a dielectric electro-active polymer based capacitive incremental actuator. The paper also provides the design of a low input voltage (24 V) and variable high output voltage...... on the output high-voltage (HV) side. Experimental results verifying the bidirectional operation of a high voltage flyback converter are presented, using a 3 kV polypropylene film capacitor as the load. The energy loss distributions of the converter when 4 kV and 4.5 kV HV MOSFETs are used on HV side...

Direct DC 10 V comparison between two programmable Josephson voltage standards made of niobium nitride (NbN)-based and niobium (Nb)-based Josephson junctions

Science.gov (United States)

Solve, S.; Chayramy, R.; Maruyama, M.; Urano, C.; Kaneko, N.-H.; Rüfenacht, A.

2018-04-01

BIPM’s new transportable programmable Josephson voltage standard (PJVS) has been used for an on-site comparison at the National Metrology Institute of Japan (NMIJ) and the National Institute of Advanced Industrial Science and Technology (AIST) (NMIJ/AIST, hereafter called just NMIJ unless otherwise noted). This is the first time that an array of niobium-based Josephson junctions with amorphous niobium silicon Nb x Si1-x barriers, developed by the National Institute of Standards and Technology4 (NIST), has been directly compared to an array of niobium nitride (NbN)-based junctions (developed by the NMIJ in collaboration with the Nanoelectronics Research Institute (NeRI), AIST). Nominally identical voltages produced by both systems agreed within 5 parts in 1012 (0.05 nV at 10 V) with a combined relative uncertainty of 7.9  ×  10-11 (0.79 nV). The low side of the NMIJ apparatus is, by design, referred to the ground potential. An analysis of the systematic errors due to the leakage current to ground was conducted for this ground configuration. The influence of a multi-stage low-pass filter installed at the output measurement leads of the NMIJ primary standard was also investigated. The number of capacitances in parallel in the filter and their insulation resistance have a direct impact on the amplitude of the systematic voltage error introduced by the leakage current, even if the current does not necessarily return to ground. The filtering of the output of the PJVS voltage leads has the positive consequence of protecting the array from external sources of noise. Current noise, when coupled to the array, reduces the width or current range of the quantized voltage steps. The voltage error induced by the leakage current in the filter is an order of magnitude larger than the voltage error in the absence of all filtering, even though the current range of steps is significantly decreased without filtering.

Application of Newton's optimal power flow in voltage/reactive power control

Energy Technology Data Exchange (ETDEWEB)

Bjelogrlic, M.; Babic, B.S. (Electric Power Board of Serbia, Belgrade (YU)); Calovic, M.S. (Dept. of Electrical Engineering, University of Belgrade, Belgrade (YU)); Ristanovic, P. (Institute Nikola Tesla, Belgrade (YU))

1990-11-01

This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

Constant voltage and constant current control implementation for electric vehicles (evs) wireless charger

Science.gov (United States)

Tampubolon, Marojahan; Pamungkas, Laskar; Hsieh, Yao Ching; Chiu, Huang Jen

2018-04-01

This paper presents the implementation of Constant Voltage (CV) and Constant Current (CC) control for a wireless charger system. A battery charging system needs these control modes to ensure the safety of the battery and the effectiveness of the charging system. Here, the wireless charger system does not employ any post-regulator stage to control the output voltage and output current of the charger. But, it uses a variable frequency control incorporated with a conventional PI control. As a result, the size and the weight of the system are reduced. This paper discusses the brief review of the SS-WPT, control strategy and implementation of the CV and CC control. Experimental hardware with 2kW output power has been performed and tested. The results show that the proposed CV and CC control method works well with the system.

Improving the voltage quality of an inverter via by-passing the harmonic current components

DEFF Research Database (Denmark)

Zhong, Qing-Chang; Blaabjerg, Frede; Guerrero, Josep M.

2012-01-01

In this paper, a control strategy is proposed to improve the total harmonic distortion (THD) of the output voltage of an inverter. The physical interpretation of the control strategy is to connect shunt resonant filters at harmonic frequencies to the output so that the harmonic current components...

Selective virtual capacitive impedance loop for harmonics voltage compensation in islanded microgrids

DEFF Research Database (Denmark)

Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

2013-01-01

Parallel inverters having LCL output filters cause voltage distortions at the point of common coupling (PCC) in islanded microgrids when non-linear loads are present. A capacitive virtual impedance loop could be used to provide selective harmonic compensation in islanded microgrids, instead of in...... resistance for selective harmonic compensation in islanded microgrids. Simulation results were given to show the suitability of the proposed algorithms in reducing the voltage harmonics at the PCC.......Parallel inverters having LCL output filters cause voltage distortions at the point of common coupling (PCC) in islanded microgrids when non-linear loads are present. A capacitive virtual impedance loop could be used to provide selective harmonic compensation in islanded microgrids, instead...... of introducing additional active or passive filters into the system that could compromise the stability of the microgrid. However, the performance of these compensation loops becomes degraded when a virtual resistance is introduced with the aim to improve the overall stability of the parallel inverters...

Integrated Three-Voltage-Booster DC-DC Converter to Achieve High Voltage Gain with Leakage-Energy Recycling for PV or Fuel-Cell Power Systems

Directory of Open Access Journals (Sweden)

Chih-Lung Shen

2015-09-01

Full Text Available In this paper, an integrated three-voltage-booster DC-DC (direct current to direct current converter is proposed to achieve high voltage gain for renewable-energy generation systems. The proposed converter integrates three voltage-boosters into one power stage, which is composed of an active switch, a coupled-inductor, five diodes, and five capacitors. As compared with conventional high step-up converters, it has a lower component count. In addition, the features of leakage-energy recycling and switching loss reduction can be accomplished for conversion efficiency improvement. While the active switch is turned off, the converter can inherently clamp the voltage across power switch and suppress voltage spikes. Moreover, the reverse-recovery currents of all diodes can be alleviated by leakage inductance. A 200 W prototype operating at 100 kHz switching frequency with 36 V input and 400 V output is implemented to verify the theoretical analysis and to demonstrate the feasibility of the proposed high step-up DC-DC converter.

Effect of argon plasma treatment on the output performance of triboelectric nanogenerator

Energy Technology Data Exchange (ETDEWEB)

Cheng, Guang-Gui, E-mail: ggcheng@ujs.edu.cn [Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou (China); Jiang, Shi-Yu; Li, Kai [Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang (China); Zhang, Zhong-Qiang [Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou (China); Wang, Ying; Yuan, Ning-Yi [Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou (China); Ding, Jian-Ning, E-mail: dingjn@ujs.edu.cn [Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang (China); Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Changzhou University, Changzhou (China); Zhang, Wei [Research Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang (China)

2017-08-01

Highlights: • Two different kinds of PDMS films were prepared by spin-coated. • The PDMS surface was plasma treated with different power and time. • The output performance of TENG was significantly enhanced by plasma treatment. • Plasma treatment effect has time-efficient, the output declines with store time. - Abstract: Physical and chemical properties of the polymer surface play great roles in the output performance of triboelectric nanogenerator (TENG). Specific texture on the surface of polymer can enlarge the contact area and enhance the power output performance of TENG. In this paper, polydimethylsiloxane (PDMS) films with smooth and micro pillar arrays on the surface were prepared respectively. The surfaces were treated by argon plasma before testing their output performance. By changing treatment parameters such as treating time and plasma power, surfaces with different roughness and their relationship were achieved. The electrical output performances of the assembled TENG for each specimen showed that argon plasma treatment has a significant etching effect on the PDMS surface and greatly strengthen its output performance. The average surface roughness of PDMS film increases with the etching time from 5 mins to 15 mins when the argon plasma power is 60 W. Nevertheless, the average surface roughness is inversely proportional to the treatment time for the power of 90W. When treated with 90 W and 5 mins, many uniform micro pillars appeared on the both PDMS surface, and the output performance of the TENG for plasma treated smooth surface is 2.6 times larger than that before treatment. The output voltage increases from 42 V to 72 V, and the short circuit current increases from 4.2 μA to 8.3 μA after plasma treatment of the micro pillar array surface. However, this plasma treatment has time-efficient due to the hydrophobic recovery property of Ar plasma treated PDMS surface, both output voltage and short circuit current decrease significantly after 3

Analog Amplitude Modulation of a High Voltage, Solid State Inductive Adder, Pulse Generator Using MOSFETS

International Nuclear Information System (INIS)

Gower, E J; Sullivan, J S

2002-01-01

High voltage, solid state, inductive adder, pulse generators have found increasing application as fast kicker pulse modulators for charged particle beams. The solid state, inductive adder, pulse generator is similar in operation to the linear induction accelerator. The main difference is that the solid state, adder couples energy by transformer action from multiple primaries to a voltage summing stalk, instead of an electron beam. Ideally, the inductive adder produces a rectangular voltage pulse at the load. In reality, there is usually some voltage variation at the load due to droop on primary circuit storage capacitors, or, temporal variations in the load impedance. Power MOSFET circuits have been developed to provide analog modulation of the output voltage amplitude of a solid state, inductive adder, pulse generator. The modulation is achieved by including MOSFET based, variable subtraction circuits in the multiple primary stack. The subtraction circuits can be used to compensate for voltage droop, or, to tailor the output pulse amplitude to provide a desired effect in the load. Power MOSFET subtraction circuits have been developed to modulate short, temporal (60-400 ns), voltage and current pulses. MOSFET devices have been tested up to 20 amps and 800 Volts with a band pass of 50 MHz. An analog modulation cell has been tested in a five cell high, voltage adder stack

E-cigarettes: voltage- and concentration-dependent loss in human lung adenocarcinoma viability.

Science.gov (United States)

Otręba, Michał; Kośmider, Leon; Knysak, Jakub; Warncke, Jared D; Sobczak, Andrzej

2018-04-17

E-cigarettes are used by millions of people despite the fact that the harmful effect of aerosol emitted from these products to the human organism is still not clear. In this paper, toxicity of vapor generated using different solutions and battery output voltage on A549 cells viability is presented. The obtained EC 50 values for commercially available propylene glycol/glycerol solution 1:1 e-liquids based on 3.2 V (0.127%), 4.0 V (0.112%) and 4.8 V (0.038%) were about 1.5-4.5 times higher than in tobacco smoke (0.0086%). Furthermore, it was shown that the increase of battery output voltage decreased A549 cell viability. In addition, commercially available extracts were more cytotoxic than laboratory made extracts. Owing to the expansiveness of e-cigarettes, it is very important to estimate their impact on public health. Our results not only confirm less cytotoxicity of e-liquid aerosol than cigarette smoke, but also demonstrate that solutions used in e-liquids and, for the first time, battery output voltage have a significant impact on cytotoxicity of e-cigarette vapor. Thus, the results of this study are very important for the current and future legal regulations on e-cigarettes. Copyright © 2018 John Wiley & Sons, Ltd.

High-voltage pulse generator synchronous with LINAC

International Nuclear Information System (INIS)

Muto, M.; Hiratsuka, Yoshio; Niimura, Nobuo

1974-01-01

High-voltage pulse generator (H.V. Flip-Flop) No.2, an improved type of No.1, is described, which is used in the structural analysis of transient phenomena in materials through the neutron TOF with a Linac. The method of producing positive and negative high-voltage pulses synchronous with the Linac is identical with that in No.1. However, No.2 has outstanding features as follows: (1) The rise time of output pulses is reduced to 0.3 msec, due to the improvement of switching circuit and the winding of a step-up transformer; (2) The widths of positive and negative pulses are variable up to maximum 8 and 16 frames, respectively (One frame = 10 msec); (3) The distribution of TOF signals from a BF 3 counter to a time analyzer is possible even in the negative voltage duration. The panel is provided with the switches for choosing pulse width and the frame for analysis, as well as the dials for setting positive/negative pulse voltage values and the respective indicating meters. (Mori, K)

A Study on Energy Saving of Single Phase Induction Motor By Voltage Control

Energy Technology Data Exchange (ETDEWEB)

Bae, Jong Moon [Pusan College of Information Technolgy, Pusan (Korea); Kim, Joon Hong [Dong Myong College, Pusan (Korea)

2001-06-01

This paper describes a simple effective method for energy saving of AC motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, TRIAC voltage control characteristics. The parameters of simplified voltage-current pattern can be determined approximately and reliably from the rated voltage and current of the motor. Experiments are focused on a single phase capacitor motor, the optimal energy saving are proved by proposed method. (author). 8 refs., 15 figs.

Programmable pulse sequence generator with multiple output lines

Science.gov (United States)

Drabczyk, Hubert

2006-10-01

This paper presents a novel concept of pulse sequence generator and its prototype as an electronic circuit testing laboratory tool. The generator has multiple output lines and is capable of using control data defining different pulse sequences to be given to the outputs. It is also possible to use different voltage levels in output signal and switch output lines for reading data from driven system. The pulse sequence generator can be used for runtime environment simulation, as hardware tester or auxiliary tool in new designs. Important design factors were to keep cost of the tool low and allow integration with other projects by using flexible architecture. The prototype was based on universal programmer with adjustable power supply, '51 microcontroller and Altera Cyclone chip. The generator communicates witch PC computer via RS232 port. Dedicated software was developed in the course of this project, to control the tool and data transmission. The prototype confirmed the possibility to create an inexpensive multipurpose laboratory tool for programming, testing and simulation of digital devices.

A comprehensive analysis and hardware implementation of control strategies for high output voltage DC-DC boost power converter

DEFF Research Database (Denmark)

Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede

2017-01-01

voltage and efficiency of classical HV converters. This paper deals with extra high-voltage (EHV) dc-dc boost converter by the application of voltage-lift technique to overcome the aforementioned deficiencies. The control strategy is based on classical proportional-integral (P-I) and fuzzy logic closed...... are performed by the DSP. The experimental results provided show good conformity with developed hypothetical predictions. Additionally, the presented study confirms that the fuzzy logic controller provides better performance than classical P-I controller under different perturbation conditions....

High voltage switch triggered by a laser-photocathode subsystem

Science.gov (United States)

Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

2013-01-08

A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

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

Science.gov (United States)

Fan, Haifeng

2011-12-01

switching loss and conduction loss are must-haves for high efficiency, while bidirectional power flow capability is a must for power management requirement. To address the demand, the phase-shift dual-halfbridge (DHB) is proposed as the constituent module of ISOP configuration for MV application. The proposed ISOP DHB converter employs zero-voltage-switching (ZVS) technique combined with LV MOSFETs to achieve low switching and conduction losses under high frequency operation, and therefore high efficiency and high power density, and bidirectional power flow as well. Secondly, a large load range of high efficiency is desired rather than only a specific load point due to the continuous operation and large load variation range of utility application, which is of high importance because of the rising energy cost. This work proposes a novel DHB converter with an adaptive commutation inductor. By utilizing an adaptive inductor as the main energy transfer element, the output power can be controlled by not only the phase shift but also the commutation inductance, which allows the circulating energy to be optimized for different load conditions to maintain ZVS under light load conditions and minimize additional conduction losses under heavy load conditions as well. As a result, the efficiency at both light and heavy load can be significantly improved compared with the conventional DHB converter, and therefore extended high-efficiency range can be achieved. In addition, current stress of switch devices can be reduced. The theoretical analysis is presented and validated by the experimental results on a 50 kHz, 1 kW dc-dc converter module. Thirdly, input-voltage sharing and output-current sharing are critical to assure the advantages of the ISOP modular configuration. To solve this issue, an identically distributed control scheme is proposed in this work. The proposed control scheme, using only one distributed voltage loop to realize both input-voltage and output-current sharing

Tuning the threshold voltage of carbon nanotube transistors by n-type molecular doping for robust and flexible complementary circuits

Science.gov (United States)

Wang, Huiliang; Wei, Peng; Li, Yaoxuan; Han, Jeff; Lee, Hye Ryoung; Naab, Benjamin D.; Liu, Nan; Wang, Chenggong; Adijanto, Eric; Tee, Benjamin C.-K.; Morishita, Satoshi; Li, Qiaochu; Gao, Yongli; Cui, Yi; Bao, Zhenan

2014-01-01

Tuning the threshold voltage of a transistor is crucial for realizing robust digital circuits. For silicon transistors, the threshold voltage can be accurately controlled by doping. However, it remains challenging to tune the threshold voltage of single-wall nanotube (SWNT) thin-film transistors. Here, we report a facile method to controllably n-dope SWNTs using 1H-benzoimidazole derivatives processed via either solution coating or vacuum deposition. The threshold voltages of our polythiophene-sorted SWNT thin-film transistors can be tuned accurately and continuously over a wide range. Photoelectron spectroscopy measurements confirmed that the SWNT Fermi level shifted to the conduction band edge with increasing doping concentration. Using this doping approach, we proceeded to fabricate SWNT complementary inverters by inkjet printing of the dopants. We observed an unprecedented noise margin of 28 V at VDD = 80 V (70% of 1/2VDD) and a gain of 85. Additionally, robust SWNT complementary metal−oxide−semiconductor inverter (noise margin 72% of 1/2VDD) and logic gates with rail-to-rail output voltage swing and subnanowatt power consumption were fabricated onto a highly flexible substrate. PMID:24639537

Evaluation of the Voltage Support Strategies for the Low Voltage Grid Connected PV

DEFF Research Database (Denmark)

Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

2010-01-01

Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from...... PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power curtailment strategies regarding the development of PV connection capacity by evaluation...... of reactive power efforts and requirement of minimum active power curtailment. Furthermore, a small scale experimental setup is built to reflect real grid interaction in the laboratory by achieving critical types of grid (weak and sufficiently stiff)....

Low Voltage Electrowetting on Ferroelectric PVDF-HFP Insulator with Highly Tunable Contact Angle Range.

Science.gov (United States)

Sawane, Yogesh B; Ogale, Satishchandra B; Banpurkar, Arun G

2016-09-14

We demonstrate a consistent electrowetting response on ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) insulator covered with a thin Teflon AF layer. This bilayer exhibits a factor of 3 enhancement in the contact angle modulation compared to that of conventional single-layered Teflon AF dielectric. On the basis of the proposed model the enhancement is attributed to the high value of effective dielectric constant (εeff ≈ 6) of the bilayer. Furthermore, the bilayer dielectric exhibits a hysteresis-free contact angle modulation over many AC voltage cycles. But the contact angle modulation for DC voltage shows a hysteresis because of the field-induced residual polarization in the ferroelectric layer. Finally, we show that a thin bilayer exhibits contact angle modulation of Δθ (U) ≈ 60° at merely 15 V amplitude of AC voltage indicating a potential dielectric for practical low voltage electrowetting applications. A proof of concept confirms electrowetting based rapid mixing of a fluorescent dye in aqueous glycerol solution for 15 V AC signal.

New pixel circuit compensating poly-si TFT threshold-voltage shift for a driving AMOLED

International Nuclear Information System (INIS)

Fan, C. L.; Lin, Y. Y.; Lin, B. S.; Chang, J. Y.; Fan, C. L.; Chang, H. C.

2010-01-01

This study presents a novel pixel circuit that uses only n-type low-temperature polycrystalline silicon (poly-Si) thin-film transistors (LTPS-TFTs) to simplify the fabrication process of active matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit consists of five switching TFTs, one driving TFT (DTFT), and two capacitors. The output current and the OLED anode voltage error rates are about 3% and 0.7%, respectively. Thus, the pixel circuit can realize uniform output current with high immunity to the poly-Si TFT threshold voltage deviation. The proposed novel pixel design has great potential for use in large-size, high-resolution AMOLED displays.

Selective Harmonic Virtual Impedance for Voltage Source Inverters with LCL filter in Microgrids

DEFF Research Database (Denmark)

Savaghebi, Mehdi; Vasquez, Juan Carlos; Jalilian, Alireza Jalilian

2012-01-01

This paper presents a new control approach for voltage source inverters ended with LCL filters for microgrid applications. The control approach consists of voltage and current inner control loops in order to fix the filter capacitor voltage and a virtual impedance loop. The virtual impedance...... is added in order to mitigate the voltage distortion after the output inductor and improve the load sharing among parallel inverters. A general case with a combined voltage harmonic and unbalance distortion is considered. In such a case, voltage distortion is mitigated by inserting capacitive virtual...... impedance for negative sequence of fundamental component as well as positive and negative sequences of main harmonic components. Furthermore, resistive virtual impedances are added at these components in order to provide a proper load sharing and make the overall system more damped. Simulation results...

Bi-directional power control system for voltage converter

Science.gov (United States)

Garrigan, Neil Richard; King, Robert Dean; Schwartz, James Edward

1999-01-01

A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals.

Application of Multipoint DC Voltage Control in VSC-MTDC System

Directory of Open Access Journals (Sweden)

Yang Xi

2013-01-01

Full Text Available The voltage-source-converter- (VSC- based multiterminal VSC-HVDC power transmission system (VSC-MTDC is an ideal approach to connect wind farm with power grid. Analyzing the characteristics of doubly fed induction generators as well as the basic principle and the control strategy of VSC-MTDC, a multiterminal DC voltage control strategy suitable for wind farm connected with VSC-MTDC is proposed. By use of PSCAD/EMTDC, the proposed control strategy is simulated, and simulation results show that using the proposed control strategy the conversion between constant power control mode and constant DC voltage control mode can be automatically implemented; thus the DC voltage stability control and reliable power output of wind farm can be ensured after the fault-caused outage of converter station controlled by constant DC voltage and under other faults. The simulation result shows that the model can fulfill multiterminal power transmission and fast response control.

Application of SMES in wind farm to improve voltage stability

International Nuclear Information System (INIS)

Shi, J.; Tang, Y.J.; Ren, L.; Li, J.D.; Chen, S.J.

2008-01-01

For the wind farms introducing doubly fed induction generators (DFIGs), voltage stability is an essential issue which influences their widely integration into the power grid. This paper proposes the application of superconducting magnetic energy storage (SMES) in the power system integrated with wind farms. SMES can control the active and reactive power flow, realizing the operation in four quadrants independently. The introducing of SMES can smooth the output power flow of the wind farms, and supply dynamic voltage support. Using MATLAB/SIMULINK, the models of the DFIG, the power grid connected and the SMES are created. Simulation results show that the voltage stability of the power system integrated with wind farms can be improved considerably

High-voltage integrated transmitting circuit with differential driving for CMUTs

DEFF Research Database (Denmark)

Llimos Muntal, Pere; Larsen, Dennis Øland; Færch, Kjartan Ullitz

2016-01-01

In this paper, a high-voltage integrated differential transmitting circuit for capacitive micromachined ultrasonic transducers (CMUTs) used in portable ultrasound scanners is presented. Due to its application, area and power consumption are critical and need to be minimized. The circuitry...... is designed and implemented in AMS 0.35 μ m high-voltage process. Measurements are performed on the fabricated integrated circuit in order to assess its performance. The transmitting circuit consists of a low-voltage control logic, pulse-triggered level shifters and a differential output stage that generates...... conditions is 0.936 mW including the load. The integrated circuits measured prove to be consistent and robust to local process variations by measurements....

A microcontroller application as X-ray machine's high voltage controller

International Nuclear Information System (INIS)

Wiranto Budi Santoso; Beny Syawaludin

2010-01-01

A micro controller application as x-ray machine's high voltage controller has been carried out. The purpose of this micro controller application is to give an accurate high voltage supply to the x-ray tube so that the x-ray machine could produce the result as expected. The micro controller based X-ray machine's high voltage controller receives an input voltage from the keypad. This input value is displayed in the LCD (Liquid Crystal Display) screen. Then micro controller uses this input data to drive a stepper motor. The stepper motor adjusts the high voltage auto transformer's output according to the input value. The micro controller is programmed using BASCOM-8051 compiler. The test results show that the stepper motor could rotate according to an input value (author)

An improved partially interleaved transformer structure for high-voltage high-frequency multiple-output applications

DEFF Research Database (Denmark)

Zhao, Bin; Ouyang, Ziwei; Andersen, Michael A. E.

2017-01-01

. The proposed structure features lower leakage inductance, smaller AC capacitance and lower rate of AC-DC resistance, which is suitable for high-frequency high-efficiency applications. A planar transformer with the proposed structure was built and tested in an LCLC resonant converter, where the input voltage...

Monolithic blue LED series arrays for high-voltage AC operation

Energy Technology Data Exchange (ETDEWEB)

Ao, Jin-Ping [Satellite Venture Business Laboratory, University of Tokushima, Tokushima 770-8506 (Japan); Sato, Hisao; Mizobuchi, Takashi; Morioka, Kenji; Kawano, Shunsuke; Muramoto, Yoshihiko; Sato, Daisuke; Sakai, Shiro [Nitride Semiconductor Co. Ltd., Naruto, Tokushima 771-0360 (Japan); Lee, Young-Bae; Ohno, Yasuo [Department of Electrical and Electronic Engineering, University of Tokushima, Tokushima 770-8506 (Japan)

2002-12-16

Design and fabrication of monolithic blue LED series arrays that can be operated under high ac voltage are described. Several LEDs, such as 3, 7, and 20, are connected in series and in parallel to meet ac operation. The chip size of a single device is 150 {mu}m x 120 {mu}m and the total size is 1.1 mm x 1 mm for a 40(20+20) LED array. Deep dry etching was performed as device isolation. Two-layer interconnection and air bridge are utilized to connect the devices in an array. The monolithic series array exhibit the expected operation function under dc and ac bias. The output power and forward voltage are almost proportional to LED numbers connected in series. On-wafer measurement shows that the output power is 40 mW for 40(20+20) LED array under ac 72 V. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

High-Voltage-Input Level Translator Using Standard CMOS

Science.gov (United States)

Yager, Jeremy A.; Mojarradi, Mohammad M.; Vo, Tuan A.; Blalock, Benjamin J.

2011-01-01

proposed integrated circuit would translate (1) a pair of input signals having a low differential potential and a possibly high common-mode potential into (2) a pair of output signals having the same low differential potential and a low common-mode potential. As used here, "low" and "high" refer to potentials that are, respectively, below or above the nominal supply potential (3.3 V) at which standard complementary metal oxide/semiconductor (CMOS) integrated circuits are designed to operate. The input common-mode potential could lie between 0 and 10 V; the output common-mode potential would be 2 V. This translation would make it possible to process the pair of signals by use of standard 3.3-V CMOS analog and/or mixed-signal (analog and digital) circuitry on the same integrated-circuit chip. A schematic of the circuit is shown in the figure. Standard 3.3-V CMOS circuitry cannot withstand input potentials greater than about 4 V. However, there are many applications that involve low-differential-potential, high-common-mode-potential input signal pairs and in which standard 3.3-V CMOS circuitry, which is relatively inexpensive, would be the most appropriate circuitry for performing other functions on the integrated-circuit chip that handles the high-potential input signals. Thus, there is a need to combine high-voltage input circuitry with standard low-voltage CMOS circuitry on the same integrated-circuit chip. The proposed circuit would satisfy this need. In the proposed circuit, the input signals would be coupled into both a level-shifting pair and a common-mode-sensing pair of CMOS transistors. The output of the level-shifting pair would be fed as input to a differential pair of transistors. The resulting differential current output would pass through six standoff transistors to be mirrored into an output branch by four heterojunction bipolar transistors. The mirrored differential current would be converted back to potential by a pair of diode-connected transistors

A fully integrated, wide-load-range, high-power-conversion-efficiency switched capacitor DC-DC converter with adaptive bias comparator for ultra-low-power power management integrated circuit

Science.gov (United States)

Asano, Hiroki; Hirose, Tetsuya; Kojima, Yuta; Kuroki, Nobutaka; Numa, Masahiro

2018-04-01

In this paper, we present a wide-load-range switched-capacitor DC-DC buck converter with an adaptive bias comparator for ultra-low-power power management integrated circuit. The proposed converter is based on a conventional one and modified to operate in a wide load range by developing a load current monitor used in an adaptive bias comparator. Measurement results demonstrated that our proposed converter generates a 1.0 V output voltage from a 3.0 V input voltage at a load of up to 100 µA, which is 20 times higher than that of the conventional one. The power conversion efficiency was higher than 60% in the load range from 0.8 to 100 µA.

Vivitron 1995, transient voltage simulation, high voltage insulator tests, electric field calculation

International Nuclear Information System (INIS)

Frick, G.; Osswald, F.; Heusch, B.

1996-01-01

Preliminary investigations showed clearly that, because of the discrete electrode structure of the Vivitron, important overvoltage leading to insulator damage can appear in case of a spark. The first high voltage tests showed damage connected with such events. This fact leads to a severe voltage limitation. This work describes, at first, studies made to understand the effects of transients and the associated over-voltage appearing in the Vivitron. Then we present the high voltage tests made with full size Vivitron components using the CN 6 MV machine as a pilot machine. Extensive field calculations were made. These involve simulations of static stresses and transient overvoltages, on insulating boards and electrodes. This work gave us the solutions for arrangements and modifications in the machine. After application, the Vivitron runs now without any sparks and damage at 20 MV. In the same manner, we tested column insulators of a new design and so we will find out how to get to higher voltages. Electric field calculation around the tie bars connecting the discrete electrodes together showed field enhancements when the voltages applied on the discrete electrodes are not equally distributed. This fact is one of the sources of discharges and voltage limitations. A scenario of a spark event is described and indications are given how to proceed towards higher voltages, in the 30 MV range. (orig.)

LIMIT SOLUTIONS OF EQUATIONS OF A DC HIGH-VOLTAGE CASCADE GENERATOR

Directory of Open Access Journals (Sweden)

V. O. Brzhezitsky

2015-04-01

Full Text Available In the paper the issue of calculating the high voltage cascade mode oscillator with a nonlinear load using the analytical method under different conditions of selection values of its components is presented. The peculiarity of the method of the study is that during multivariate calculations output parameters load generator remain unchanged. For high-voltage cascade direct current power found conditions under which can be significantly reduced high capacity capacitors cascade generator. The calculations show that acceptable for practical applications of high-voltage characteristics of cascade generators can be achieved with substantial reduction of the volume of their constituents, and thus substantial decline in their value.

Design of spherical electron gun for ultra high frequency, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L. M.

2016-01-01

Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

Design of spherical electron gun for ultra high frequency, CW power inductive output tube

Energy Technology Data Exchange (ETDEWEB)

Kaushik, Meenu, E-mail: mkceeri@gmail.com; Joshi, L. M., E-mail: lmj1953@gmail.com [Microwave Tubes Division, CSIR-Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India)

2016-03-09

Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

On the modelling of linear-assisted DC-DC voltage regulators for photovoltaic solar energy systems

Science.gov (United States)

Martínez-García, Herminio; García-Vílchez, Encarna

2017-11-01

This paper shows the modelling of linear-assisted or hybrid (linear & switching) DC/DC voltage regulators. In this kind of regulators, an auxiliary linear regulator is used, which objective is to cancel the ripple at the output voltage and provide fast responses for load variations. On the other hand, a switching DC/DC converter, connected in parallel with the linear regulator, allows to supply almost the whole output current demanded by the load. The objective of this topology is to take advantage of the suitable regulation characteristics that series linear voltage regulators have, but almost achieving the high efficiency that switching DC/DC converters provide. Linear-assisted DC/DC regulators are feedback systems with potential instability. Therefore, their modelling is mandatory in order to obtain design guidelines and assure stability of the implemented power supply system.

A highly sensitive RF-to-DC power converter with an extended dynamic range

KAUST Repository

Almansouri, Abdullah Saud Mohammed

2017-10-24

This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross-coupled rectifier, the proposed design offers 3.2× the dynamic range. It is also highly sensitive and requires −18 dBm of input power to produce a 1 V-output voltage when operating with a 100 kΩ load. Furthermore, the proposed design offers an open circuit sensitivity of −23.4 dBm and a peak power conversion efficiency of 67%.

Analysis and design of a high-efficiency zero-voltage-switching step ...

Indian Academy of Sciences (India)

to soft-switching operation of the power switches and output diodes, the ... However, the complexity and the overall cost are raised and the system ... the proposed converter has a voltage doubler structure which consists of two secondary wind-.

Design of a Programmable Gain, Temperature Compensated Current-Input Current-Output CMOS Logarithmic Amplifier.

Science.gov (United States)

Ming Gu; Chakrabartty, Shantanu

2014-06-01

This paper presents the design of a programmable gain, temperature compensated, current-mode CMOS logarithmic amplifier that can be used for biomedical signal processing. Unlike conventional logarithmic amplifiers that use a transimpedance technique to generate a voltage signal as a logarithmic function of the input current, the proposed approach directly produces a current output as a logarithmic function of the input current. Also, unlike a conventional transimpedance amplifier the gain of the proposed logarithmic amplifier can be programmed using floating-gate trimming circuits. The synthesis of the proposed circuit is based on the Hart's extended translinear principle which involves embedding a floating-voltage source and a linear resistive element within a translinear loop. Temperature compensation is then achieved using a translinear-based resistive cancelation technique. Measured results from prototypes fabricated in a 0.5 μm CMOS process show that the amplifier has an input dynamic range of 120 dB and a temperature sensitivity of 230 ppm/°C (27 °C- 57°C), while consuming less than 100 nW of power.

Class D audio amplifier with 4th order output filter and self-oscillating full-state hysteresis based feedback driving capacitive transducers

OpenAIRE

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

A practical solution is presented for the design of a non-isolated high voltage DC/AC power converter. The converter is intended to be used as a class D audio amplifier for a Dielectric Electro Active Polymer (DEAP) transducer. A simple and effective hysteretic control scheme for the converter (buck with fourth- order output filter) is developed and analyzed. The proposed design is verified experimentally by a 125 VAR prototype amplifier, capable of delivering a peak output voltage of 240 V w...

An analytic current-voltage model for quasi-ballistic III-nitride high electron mobility transistors

Science.gov (United States)

Li, Kexin; Rakheja, Shaloo

2018-05-01

We present an analytic model to describe the DC current-voltage (I-V) relationship in scaled III-nitride high electron mobility transistors (HEMTs) in which transport within the channel is quasi-ballistic in nature. Following Landauer's transport theory and charge calculation based on two-dimensional electrostatics that incorporates negative momenta states from the drain terminal, an analytic expression for current as a function of terminal voltages is developed. The model interprets the non-linearity of access regions in non-self-aligned HEMTs. Effects of Joule heating with temperature-dependent thermal conductivity are incorporated in the model in a self-consistent manner. With a total of 26 input parameters, the analytic model offers reduced empiricism compared to existing GaN HEMT models. To verify the model, experimental I-V data of InAlN/GaN with InGaN back-barrier HEMTs with channel lengths of 42 and 105 nm are considered. Additionally, the model is validated against numerical I-V data obtained from DC hydrodynamic simulations of an unintentionally doped AlGaN-on-GaN HEMT with 50-nm gate length. The model is also verified against pulsed I-V measurements of a 150-nm T-gate GaN HEMT. Excellent agreement between the model and experimental and numerical results for output current, transconductance, and output conductance is demonstrated over a broad range of bias and temperature conditions.

Utility Interfaced Pulse-Width Modulation of Solar Fed Voltage ...

African Journals Online (AJOL)

Utility Interfaced Pulse-Width Modulation of Solar Fed Voltage Source Inverter Using Fixed-Band Hysteresis Current Controller Method. ... with the conversion of solar energy into electrical energy; boosting the dc power; inversion of the dc to ac and then synchronization of the inverter output with the utility, and consequently, ...

Commissioning of output factors for uniform scanning proton beams

International Nuclear Information System (INIS)

Zheng Yuanshui; Ramirez, Eric; Mascia, Anthony; Ding Xiaoning; Okoth, Benny; Zeidan, Omar; Hsi Wen; Harris, Ben; Schreuder, Andries N.; Keole, Sameer

2011-01-01

Purpose: Current commercial treatment planning systems are not able to accurately predict output factors and calculate monitor units for proton fields. Patient-specific field output factors are thus determined by either measurements or empirical modeling based on commissioning data. The objective of this study is to commission output factors for uniform scanning beams utilized at the ProCure proton therapy centers. Methods: Using water phantoms and a plane parallel ionization chamber, the authors first measured output factors with a fixed 10 cm diameter aperture as a function of proton range and modulation width for clinically available proton beams with ranges between 4 and 31.5 cm and modulation widths between 2 and 15 cm. The authors then measured the output factor as a function of collimated field size at various calibration depths for proton beams of various ranges and modulation widths. The authors further examined the dependence of the output factor on the scanning area (i.e., uncollimated proton field), snout position, and phantom material. An empirical model was developed to calculate the output factor for patient-specific fields and the model-predicted output factors were compared to measurements. Results: The output factor increased with proton range and field size, and decreased with modulation width. The scanning area and snout position have a small but non-negligible effect on the output factors. The predicted output factors based on the empirical modeling agreed within 2% of measurements for all prostate treatment fields and within 3% for 98.5% of all treatment fields. Conclusions: Comprehensive measurements at a large subset of available beam conditions are needed to commission output factors for proton therapy beams. The empirical modeling agrees well with the measured output factor data. This investigation indicates that it is possible to accurately predict output factors and thus eliminate or reduce time-consuming patient-specific output

Fifth harmonic and sag impact on PMSG wind turbines with a balancing new strategy for capacitor voltages

International Nuclear Information System (INIS)

Seixas, M.; Melício, R.; Mendes, V.M.F.

2014-01-01

Highlights: • Impact on wind turbines due to fifth harmonic and sag content. • Converter topologies considered are two-level and three-level ones. • Controllers are based on PI and fractional-order methods. • New control strategy for the selection of output voltage vectors. • Balancing voltages in the DC-link capacitors. - Abstract: This paper deals with the computing simulation of the impact on permanent magnet synchronous generator wind turbines due to fifth harmonic content and grid voltage decrease. Power converter topologies considered in the simulations are the two-level and the three-level ones. The three-level converters are limited by unbalance voltages in the DC-link capacitors. In order to lessen this limitation, a new control strategy for the selection of the output voltage vectors is proposed. Controller strategies considered in the simulation are respectively based on proportional integral and fractional-order controllers. Finally, a comparison between the results of the simulations with the two controller strategies is presented in order to show the main advantage of the proposed strategy

Conservation voltage regulation (CVR) applied to energy savings by voltage-adjusting equipment through AMI

Science.gov (United States)

Lan, B.-R.; Chang, C.-A.; Huang, P.-Y.; Kuo, C.-H.; Ye, Z.-J.; Shen, B.-C.; Chen, B.-K.

2017-11-01

Conservation voltage reduction (CVR) includes peak demand reduction, energy conservation, carbon emission reduction, and electricity bill reduction. This paper analyzes the energy-reduction of Siwei Feeders with applying CVR, which are situated in Penghu region and equipped with smart meters. Furthermore, the applicable voltage reduction range for the feeders will be explored. This study will also investigate how the CVR effect and energy conservation are improved with the voltage control devices integrated. The results of this study can serve as a reference for the Taiwan Power Company to promote and implement voltage reduction and energy conservation techniques. This study is expected to enhance the energy-reduction performance of the Penghu Low Carbon Island Project.

Test Operations Procedure (TOP) 05-2-543 Enhanced Flight Termination Receiver (EFTR) Range Certification Testing

Science.gov (United States)

2011-07-25

35 5.10 Signal Strength Telemetry Output ( SSTO ) (Test Number 10) ............ 38 5.11 Operational...All command outputs and monitor outputs shall respond properly. TOP 05-2-543 25 July 2011 38 5.10 Signal Strength Telemetry Output ( SSTO ...Test Number 10). a. Purpose. This test verifies that the signal strength telemetry output ( SSTO ) voltage is monotonic and directly related to the

Analysis and Design of Symmetrical Capacitor Diode Voltage Multiplier Driven by LCL-T Resonant Converter

Science.gov (United States)

Malviya, Devesh; Borage, Mangesh Balkrishna; Tiwari, Sunil

2017-12-01

This paper investigates the possibility of application of Resonant Immittance Converters (RICs) as a current source for the current-fed symmetrical Capacitor-Diode Voltage Multiplier (CDVM) with LCL-T Resonant Converter (RC) as an example. Firstly, detailed characterization of the current-fed symmetrical CDVM is carried out using repeated simulations followed by the normalization of the simulation results in order to derive the closed-form curve fit equations to predict the operating modes, output voltage and ripple in terms of operating parameters. RICs, due to their ability to convert voltage source into a current source, become a possible candidate for the realization of current source for the current-fed symmetrical CDVM. Detailed analysis, optimization and design of LCL-T RC with CDVM is performed in this paper. A step by step design procedure for the design of CDVM and the converter is proposed. A 5-stage prototype symmetrical CDVM driven by LCL-T RC to produce 2.5 kV, 50 mA dc output voltage is designed, built and tested to validate the findings of the analysis and simulation.

A Novel Realization of Low-Power and Low-Distortion Multiplier Circuit with Improved Dynamic Range

Directory of Open Access Journals (Sweden)

Ali Naderi Saatlo

2017-01-01

Full Text Available A novel topology of four-quadrant analog multiplier circuit is presented in this paper. The voltage mode technique is employed to design the circuit in CMOS technology. The dynamic input and output ranges of the circuit are improved owing to the fact that the circuit works in the saturation region not in weak inversion. Also the proposed multiplier is suitable for low voltage operation and its power consumption is relatively low. In order to verify the performance of the proposed circuit, performance of the circuit affected by second order effects including transistor mismatch and mobility reduction is analyzed in detail. It will be shown that any conceivable mismatch in the transistor parameters leads to second harmonic distortion. Additionally, the effect of mobility reduction in the third harmonic distortion will be computed. In order to simulate the circuit, Cadence and HSPICE software are used with TSMC level 49 (BSIM3v3 parameters for 0.18 μm CMOS technology, where under supply voltage of 1.5 V, total power consumption is 44 µW, the corresponding average nonlinearity remains as low as 1 %, and the input range of the circuit is ± 400 mV.

Voltage-Mode All-Pass Filters Including Minimum Component Count Circuits

Directory of Open Access Journals (Sweden)

Sudhanshu Maheshwari

2007-01-01

Full Text Available This paper presents two new first-order voltage-mode all-pass filters using a single-current differencing buffered amplifier and four passive components. Each circuit is compatible to a current-controlled current differencing buffered amplifier with only two passive elements, thus resulting in two more circuits, which employ a capacitor, a resistor, and an active element, thus using a minimum of active and passive component counts. The proposed circuits possess low output impedance, and hence can be easily cascaded for voltage-mode systems. PSPICE simulation results are given to confirm the theory.

Design and development of high voltage and high frequency center tapped transformer for HVDC test generator

International Nuclear Information System (INIS)

Thaker, Urmil; Saurabh Kumar; Amal, S.; Baruah, U.K.; Bhatt, Animesh

2015-01-01

A High Voltage center tapped transformer for high frequency application had been designed, fabricated, and tested. It was designed as a part of 200 kV HVDC Test Generator. The High Frequency operation of transformer increases power density. Therefore it is possible to reduce power supply volume. The step up ratio in High Voltage transformer is limited due to stray capacitance and leakage inductance. The limit was overcome by winding multi secondary outputs. Switching frequency of transformer was 15.8 kHz. Input and output voltages of transformer were 270V and 16.5kV-0V-16.5kV respectively. Power rating of transformer is 7kVA. High Voltage transformer with various winding and core arrangement was fabricated to check variation in electrical characteristics. The transformer used a ferrite core (E Type) and nylon insulated primary and secondary bobbins. Two set of E-E geometry cores had been stacked in order to achieve the estimated core volume. Compared with traditional high voltage transformer, this transformer had good thermal behavior, good line insulation properties and a high power density. In this poster, design procedures, development stages and test results of high voltage and high frequency transformer are presented. Results of various parameters such as transformer loss, temperature rise, insulation properties, impedance of primary and secondary winding, and voltage regulation are discussed. (author)

Voltage-assisted polymer wafer bonding

International Nuclear Information System (INIS)

Varsanik, J S; Bernstein, J J

2012-01-01

Polymer wafer bonding is a widely used process for fabrication of microfluidic devices. However, best practices for polymer bonds do not achieve sufficient bond strength for many applications. By applying a voltage to a polymer bond in a process called voltage-assisted bonding, bond strength is shown to improve dramatically for two polymers (Cytop™ and poly(methyl methacrylate)). Several experiments were performed to provide a starting point for further exploration of this technique. An optimal voltage range is experimentally observed with a reduction in bonding strength at higher voltages. Additionally, voltage-assisted bonding is shown to reduce void diameter due to bond defects. An electrostatic force model is proposed to explain the improved bond characteristics. This process can be used to improve bond strength for most polymers. (paper)

Wide-range bipolar pulse conductance instrument employing current and voltage modes with sampled or integrated signal acquisition

Energy Technology Data Exchange (ETDEWEB)

Calhoun, R K; Holler, F J [Kentucky Univ., Lexington, KY (United States). Dept. of Chemistry; Geiger, jr, R F; Nieman, T A [Illinois Univ., Urbana, IL (United States). Dept. of Chemistry; Caserta, K J [Procter and Gamble Co., Cincinnati, OH (United States)

1991-11-05

An instrument for measuring solution conductance using the bipolar pulse technique is described. The instrument is capable of measuring conductances in the range of 5x10{sup -9}-10{Omega}{sup -1} with 1% accuracy or better in as little as 32 {mu}s. Accuracy of 0.001-0.01% is achievable over the range 1x10{sup -6}-1{Omega}{sup -1}. Circuitry and software are described that allow the instrument to adjust automatically the pulse height, pulse duration, excitation mode (current or voltage pulse) and data acquisition mode (sampled or integrated) to acquire data of optimum accuracy and precision. The urease-catalyzed decomposition of urea is used to illustrate the versality of the instrument, and other applications are cited. (author). 60 refs.; 7 figs.; 2 tabs.

An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier

Science.gov (United States)

Lee, Sin-woo; Do, Hyun-Lark

2016-12-01

This paper proposed an isolated bridgeless AC-DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input-output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.

Model Based Optimization of Integrated Low Voltage DC-DC Converter for Energy Harvesting Applications

Science.gov (United States)

Jayaweera, H. M. P. C.; Muhtaroğlu, Ali

2016-11-01

A novel model based methodology is presented to determine optimal device parameters for the fully integrated ultra low voltage DC-DC converter for energy harvesting applications. The proposed model feasibly contributes to determine the maximum efficient number of charge pump stages to fulfill the voltage requirement of the energy harvester application. The proposed DC-DC converter based power consumption model enables the analytical derivation of the charge pump efficiency when utilized simultaneously with the known LC tank oscillator behavior under resonant conditions, and voltage step up characteristics of the cross-coupled charge pump topology. The verification of the model has been done using a circuit simulator. The optimized system through the established model achieves more than 40% maximum efficiency yielding 0.45 V output with single stage, 0.75 V output with two stages, and 0.9 V with three stages for 2.5 kΩ, 3.5 kΩ and 5 kΩ loads respectively using 0.2 V input.

High voltage pulse system for the streamer chamber supply of the GIBS spectrometer

International Nuclear Information System (INIS)

Aksinenko, V.D.; Glagoleva, N.S.; Dement'ev, E.A.; Kaminskij, N.I.; Matyushin, A.T.; Matyushin, V.T.; Rozhnyatovskaya, S.A.; Ryakhovskij, V.N.; Nurgozhin, N.N.; Khusainov, E.K.

1987-01-01

Results of development and testing of high voltage pulse system HVPS for the streamer chamber supply of the GIBS spectrometer are presented. HVPS consists of the following basic blocks: nanosecond pulse high voltage generator, high voltage charging supply, trigger generator, chamber parameter control devices, gas-oil vacuuming supply systems, auxiliary and fire-prevention devices. The system blocks are described. Experimental results of HVPC testing are presented. HVPC provides a reliable (10 5 operations) of streamer chamber supply with high voltage pulse parameters: amplitude - 500 kV, amplitude instability (0.5-1.5)%, pulse duration - 12 ns, delay time - 500 ns, delay instability (2.5-5)%, mean frequency of output a signals - 0.1 Hz

Recording membrane potential changes through photoacoustic voltage sensitive dye

Science.gov (United States)

Zhang, Haichong K.; Kang, Jeeun; Yan, Ping; Abou, Diane S.; Le, Hanh N. D.; Thorek, Daniel L. J.; Kang, Jin U.; Gjedde, Albert; Rahmim, Arman; Wong, Dean F.; Loew, Leslie M.; Boctor, Emad M.

2017-03-01

Monitoring of the membrane potential is possible using voltage sensitive dyes (VSD), where fluorescence intensity changes in response to neuronal electrical activity. However, fluorescence imaging is limited by depth of penetration and high scattering losses, which leads to low sensitivity in vivo systems for external detection. In contrast, photoacoustic (PA) imaging, an emerging modality, is capable of deep tissue, noninvasive imaging by combining near infrared light excitation and ultrasound detection. In this work, we develop the theoretical concept whereby the voltage-dependent quenching of dye fluorescence leads to a reciprocal enhancement of PA intensity. Based on this concept, we synthesized a novel near infrared photoacoustic VSD (PA-VSD) whose PA intensity change is sensitive to membrane potential. In the polarized state, this cyanine-based probe enhances PA intensity while decreasing fluorescence output in a lipid vesicle membrane model. With a 3-9 μM VSD concentration, we measured a PA signal increase in the range of 5.3 % to 18.1 %, and observed a corresponding signal reduction in fluorescence emission of 30.0 % to 48.7 %. A theoretical model successfully accounts for how the experimental PA intensity change depends on fluorescence and absorbance properties of the dye. These results not only demonstrate the voltage sensing capability of the dye, but also indicate the necessity of considering both fluorescence and absorbance spectral sensitivities in order to optimize the characteristics of improved photoacoustic probes. Together, our results demonstrate photoacoustic sensing as a potential new modality for sub-second recording and external imaging of electrophysiological and neurochemical events in the brain.

Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

KAUST Repository

Ouda, Mahmoud H.

2016-08-29

A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of -15.2dBm (30μW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kω load. © 2004-2012 IEEE.

130 kV 130 A high voltage switching mode power supply for neutral beam injectors-Control issues and algorithms

International Nuclear Information System (INIS)

Ganuza, D.; Garcia, F.; Zulaika, M.; Perez, A.; Jones, T.T.C.

2005-01-01

The company JEMA has delivered to the Joint European Torus (JET facility in Culham) two high voltage switching mode power supplies (HVSMPS) each rated 130 kVdc and 130 A. One HVSMPS feeds the grids of two PINI loads. This paper describes the main control issues and the algorithms developed for the project. The most demanding requirements from the control point of view is an absolute accuracy of ±1300 V and the possibility of performing up to 255 re-applications of the high voltage during a 20 s pulse. Keeping the output voltage ripple to the specified tolerance has been a major achievement of the control system. Since the output stage is formed of several modules (120) connected in series, their stray capacitance to ground significantly influences the individual contribution of each single module to the global output voltage. Two complementary techniques have been used to balance the effects of the stray capacities. The fast re-applications requirement has a significant impact on the intermediate dc link. This section is composed of a capacity of 0.83 F, which feeds the 120 invertor modules. The dc link is fed by a 12 pulse SCR rectifier, whose matching transformers are connected to the 36 kV grid. Every re-application and every voltage shutdown supposes a quasi-instantaneous power step of 17 MW. Fast open loop algorithms have been implemented in order to keep the dc link voltage within acceptable margins. Moreover, the HVSMPS output characteristics have to be maintained during the rapid and important voltage fluctuations of the 36 kV mains (28-37 kV). The general control system is based on a Simatic S7 PLC, and a SCADA user interface. Up to 1000 signals are acquired. The control system has shown to be also a useful tool to allow for a rapid and accurate identification of faults and their origin

Optimal Design of a Push-Pull-Forward Half-Bridge (PPFHB) Bidirectional DC–DC Converter With Variable Input Voltage

DEFF Research Database (Denmark)

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high-frequency tr......This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high...

Light-weight DC to very high voltage DC converter

Energy Technology Data Exchange (ETDEWEB)

Druce, Robert L. (Union City, CA); Kirbie, Hugh C. (Dublin, CA); Newton, Mark A. (Livermore, CA)

1998-01-01

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

Fast switching thyristor applied in nanosecond-pulse high-voltage generator with closed transformer core.

Science.gov (United States)

Li, Lee; Bao, Chaobing; Feng, Xibo; Liu, Yunlong; Fochan, Lin

2013-02-01

For a compact and reliable nanosecond-pulse high-voltage generator (NPHVG), the specification parameter selection and potential usage of fast controllable state-solid switches have an important bearing on the optimal design. The NPHVG with closed transformer core and fast switching thyristor (FST) was studied in this paper. According to the analysis of T-type circuit, the expressions for the voltages and currents of the primary and secondary windings on the transformer core of NPHVG were deduced, and the theoretical maximum analysis was performed. For NPHVG, the rise-rate of turn-on current (di/dt) across a FST may exceed its transient rating. Both mean and maximum values of di/dt were determined by the leakage inductances of the transformer, and the difference is 1.57 times. The optimum winding ratio is helpful to getting higher voltage output with lower specification FST, especially when the primary and secondary capacitances have been established. The oscillation period analysis can be effectively used to estimate the equivalent leakage inductance. When the core saturation effect was considered, the maximum di/dt estimated from the oscillating period of the primary current is more accurate than one from the oscillating period of the secondary voltage. Although increasing the leakage inductance of NPHVG can decrease di/dt across FST, it may reduce the output peak voltage of the NPHVG.

Biased low differential input impedance current receiver/converter device and method for low noise readout from voltage-controlled detectors

Science.gov (United States)

Degtiarenko, Pavel V [Williamsburg, VA; Popov, Vladimir E [Newport News, VA

2011-03-22

A first stage electronic system for receiving charge or current from voltage-controlled sensors or detectors that includes a low input impedance current receiver/converter device (for example, a transimpedance amplifier), which is directly coupled to the sensor output, a source of bias voltage, and the device's power supply (or supplies), which use the biased voltage point as a baseline.

Governmentally amplified output volatility

Science.gov (United States)

Funashima, Yoshito

2016-11-01

Predominant government behavior is decomposed by frequency into several periodic components: updating cycles of infrastructure, Kuznets cycles, fiscal policy over business cycles, and election cycles. Little is known, however, about the theoretical impact of such cyclical behavior in public finance on output fluctuations. Based on a standard neoclassical growth model, this study intends to examine the frequency at which public investment cycles are relevant to output fluctuations. We find an inverted U-shaped relationship between output volatility and length of cycle in public investment. This implies that periodic behavior in public investment at a certain frequency range can cause aggravated output resonance. Moreover, we present an empirical analysis to test the theoretical implication, using the U.S. data in the period from 1968 to 2015. The empirical results suggest that such resonance phenomena change from low to high frequency.

A PASSIVELY MODE-LOCKED CR4+:FORSTERITE LASER WITH ELEСTRONICALLY CONTROLLED OUTPUT CHARACTERISTICS

Directory of Open Access Journals (Sweden)

S. A. Zolotovskaya

2011-01-01

Full Text Available Applicability of electronic control of laser output parameters to bulk solid-state laser sources is demonstrated. A single laser source with variable pulse duration for novel imaging and manipulation systems is presented. Stable passive mode-locking of a Cr4+:forsterite laser using a voltage controlled p-n junction quantum dot saturable absorber was achieved. Output shortening from 17,4 to 6,4 ps near-transform limited pulses was obtained by applying reverse bias.

Cooled solar PV panels for output energy efficiency optimisation

International Nuclear Information System (INIS)

Peng, Zhijun; Herfatmanesh, Mohammad R.; Liu, Yiming

2017-01-01

Highlights: • Effects of cooling on solar PV performance have been experimentally investigated. • As a solar panel is cooled down, the electric output can have significant increase. • A cooled solar PV system has been proposed for resident application. • Life cycle assessment suggests the cost payback time of cooled PV can be reduced. - Abstract: As working temperature plays a critical role in influencing solar PV’s electrical output and efficacy, it is necessary to examine possible way for maintaining the appropriate temperature for solar panels. This research is aiming to investigate practical effects of solar PV surface temperature on output performance, in particular efficiency. Experimental works were carried out under different radiation condition for exploring the variation of the output voltage, current, output power and efficiency. After that, the cooling test was conducted to find how much efficiency improvement can be achieved with the cooling condition. As test results show the efficiency of solar PV can have an increasing rate of 47% with the cooled condition, a cooling system is proposed for possible system setup of residential solar PV application. The system performance and life cycle assessment suggest that the annual PV electric output efficiencies can increase up to 35%, and the annual total system energy efficiency including electric output and hot water energy output can increase up to 107%. The cost payback time can be reduced to 12.1 years, compared to 15 years of the baseline of a similar system without cooling sub-system.

The pulse-driven AC Josephson voltage normal

International Nuclear Information System (INIS)

Kieler, Oliver

2016-01-01

In this contribution quantum precise alternating-voltage sources are presented, which make the generation of arbitrary wave forms with highest spectral purity with a high bandwidth from DC up to the MHz range possible. Heartpiece of these Josephson voltage normals is a serial circuit of many thousand Josephson contacts, which make by irradiation with high-frequency radiation (microwaves) the generation of highly precise voltage values possible. Thereby in the current-voltage characteristics stages of constant voltage, so called Shapiro stages, occur. Illustratively these stages can be described by the transfer of a certain number of flux quanta through the Josephson contacts.

Low cardiac output as physiological phenomenon in hibernating, free-ranging Scandinavian brown bears (Ursus arctos) - an observational study.

Science.gov (United States)

Jørgensen, Peter Godsk; Arnemo, Jon; Swenson, Jon E; Jensen, Jan S; Galatius, Søren; Frøbert, Ole

2014-09-16

Despite 5-7 months of physical inactivity during hibernation, brown bears (Ursus arctos) are able to cope with physiological conditions that would be detrimental to humans. During hibernation, the tissue metabolic demands fall to 25% of the active state. Our objective was to assess cardiac function associated with metabolic depression in the hibernating vs. active states in free-ranging Scandinavian brown bears. We performed echocardiography on seven free-ranging brown bears in Dalarna, Sweden, anesthetized with medetomidine-zolazepam-tiletamine-ketamine during winter hibernation in February 2013 and with medetomidine-zolazepam-tiletamine during active state in June 2013. We measured cardiac output noninvasively using estimates of hemodynamics obtained by pulsed wave Doppler echocardiography and 2D imaging. Comparisons were made using paired T-tests. During hibernation, all hemodynamic indices were significantly decreased (hibernating vs. active state): mean heart rate was 26.0 (standard deviation (SD): 5.6) beats per min vs. 75.0 (SD: 17.1) per min (P=0.002), mean stroke volume 32.3 (SD: 5.2) ml vs. 47.1 (SD: 7.9) ml (P=0.008), mean cardiac output 0.86 (SD: 0.31) l/min vs. 3.54 (SD: 1.04) l/min (P=0.003), and mean cardiac index 0.63 (SD: 0.21) l/min/kg vs. 2.45 (SD: 0.52) l/min/ m2 (Pbears during hibernation, despite the absence of atrial arrhythmias and valvular disease. Free-ranging brown bears demonstrate hemodynamics comparable to humans during active state, whereas during hibernation, we documented extremely low-flow hemodynamics. Understanding these physiological changes in bears may help to gain insight into the mechanisms of cardiogenic shock and heart failure in humans.

Voltage linear transformation circuit design

Science.gov (United States)

Sanchez, Lucas R. W.; Jin, Moon-Seob; Scott, R. Phillip; Luder, Ryan J.; Hart, Michael

2017-09-01

Many engineering projects require automated control of analog voltages over a specified range. We have developed a computer interface comprising custom hardware and MATLAB code to provide real-time control of a Thorlabs adaptive optics (AO) kit. The hardware interface includes an op amp cascade to linearly shift and scale a voltage range. With easy modifications, any linear transformation can be accommodated. In AO applications, the design is suitable to drive a range of different types of deformable and fast steering mirrors (FSM's). Our original motivation and application was to control an Optics in Motion (OIM) FSM which requires the customer to devise a unique interface to supply voltages to the mirror controller to set the mirror's angular deflection. The FSM is in an optical servo loop with a wave front sensor (WFS), which controls the dynamic behavior of the mirror's deflection. The code acquires wavefront data from the WFS and fits a plane, which is subsequently converted into its corresponding angular deflection. The FSM provides +/-3° optical angular deflection for a +/-10 V voltage swing. Voltages are applied to the mirror via a National Instruments digital-to-analog converter (DAC) followed by an op amp cascade circuit. This system has been integrated into our Thorlabs AO testbed which currently runs at 11 Hz, but with planned software upgrades, the system update rate is expected to improve to 500 Hz. To show that the FSM subsystem is ready for this speed, we conducted two different PID tuning runs at different step commands. Once 500 Hz is achieved, we plan to make the code and method for our interface solution freely available to the community.

Voltage-regulating constant-current sources in a linear induction accelerator

International Nuclear Information System (INIS)

Zhao Juan; Cao Kefeng; Deng Jianjun; Zhu Lijun; Yang Jia; Ye Chao; Huang Bin; Cao Ningxiang; Dong Jinxuan; Zhang Jichang; Yu Zhiguo; Chen Min

2002-01-01

Constant-current Sources are one of key units in a linear induction accelerator. The requirements for the sources are to supply stable direct current of high power for the induction coil, be easy to computer-control and highly stable and reliable. Applying the technique of linear current source regulating in series, the primary voltage of the power transformer is regulated through an MJYS-JL-350A type three-phase alterative voltage-regulating module. The output current variation is 300-500 A when the load variation is 0.06-0.1 Ω and the voltage drop of the regulator tube is controlled within 8 V±2V when the variation of mains voltage is in ±10%. Both the current ripple and stability meet the technical requirements. The constant-current sources are controlled through an industrial controller. For each of the constant-current sources has a smallest system comprised of 8051 which is communication-controlled through a RS-485 interface, the sources can be controlled remotely

Development of Electromechanical Architectures for AC Voltage Metrology

Directory of Open Access Journals (Sweden)

Alexandre BOUNOUH

2010-12-01

Full Text Available This paper presents results of work undertaken for exploring MEMS capabilities to fabricate AC voltage references for electrical metrology and high precision instrumentation through the mechanical-electrical coupling in MEMS. From first MEMS test structures previously realized, a second set of devices with improved characteristics has been developed and fabricated with Silicon on Insulator (SOI Surface Micromachining process. These MEMS exhibit pull-in voltages of 5 V and 10 V to match with the best performance of the read-out electronics developed for driving the MEMS. Deep Level Transient Spectroscopy measurements carried out on the new design show resonance frequencies of about only some kHz, and the stability of the MEMS output voltage measured at 100 kHz has been found very promising for the best samples where the relative deviation from the mean value over almost 12 hours showed a standard deviation of about 6.3 ppm.

Constancy of radiation output during diagnostic X-ray exposures

International Nuclear Information System (INIS)

Ardran, G.M.; Crooks, H.E.; Birch, R.

1978-01-01

Variation in X-ray output and quality during a diagnostic exposure can be undesirable and may result in unnecessary dose to the patient. When significant build-up or decay periods are present errors will arise if factors obtained under steady-state conditions are employed to estimate the exposure. These parameters must be taken into account when calibrating X-ray generators. A variable speed spinning film device and a spectrometry system have been used to measure the variations under fluoroscopic and radiographic conditions for a number of generators. Variations in output due to filament heating, voltage supply and rectification, cable capacity and target pitting have been demonstrated. At low fluoroscopic currents, large surges and long decays have been observed; the significance of these effects is considered. (author)

Determining the Frequency for Load-Independent Output Current in Three-Coil Wireless Power Transfer System

Directory of Open Access Journals (Sweden)

Longzhao Sun

2015-09-01

Full Text Available Conditions for load-independent output voltage or current in two-coil wireless power transfer (WPT systems have been studied. However, analysis of load-independent output current in three-coil WPT system is still lacking in previous studies. This paper investigates the output current characteristics of a three-coil WPT system against load variations, and determines the operating frequency to achieve a constant output current. First, a three-coil WPT system is modeled by circuit theory, and the analytical expression of the root-mean-square of the output current is derived. By substituting the coupling coefficients, the quality factor, and the resonant frequency of each coil, we propose a method of calculating the frequency for load-independent output current in a three-coil WPT system, which indicates that there are two frequencies that can achieve load-independent output current. Experiments are conducted to validate these analytical results.

Capacitor current feedback for output filter damping in switched-mode magnet power supplies

International Nuclear Information System (INIS)

Paven Kumar, M.R.; Kim, J.M.S.

1994-01-01

In magnet power supplies for a particle accelerator system, a second-order low-pass filter is used to reduce the output current ripple content within specifications. The output filter must be properly damped in order to avoid any large amplification at the resonant frequency and large transient responses of voltages and currents at the step change of the line voltage. Conventionally, a series combination of resistance and capacitance is added in parallel with the filter capacitor to provide the required damping. This approach, however, requires a large dc-blocking capacitor which has to be several times larger than the filter capacitor. In this paper, a filter damping technique using capacitor current feedback is presented. The basic concept of the capacitor current feedback is established using a linear model of the converter involved, and then a sampled-data model of the converter is used to analyze the filter damping technique. The filter damping effect of the capacitor current feedback is verified experimentally

Reference voltage calculation method based on zero-sequence component optimisation for a regional compensation DVR

Science.gov (United States)

Jian, Le; Cao, Wang; Jintao, Yang; Yinge, Wang

2018-04-01

This paper describes the design of a dynamic voltage restorer (DVR) that can simultaneously protect several sensitive loads from voltage sags in a region of an MV distribution network. A novel reference voltage calculation method based on zero-sequence voltage optimisation is proposed for this DVR to optimise cost-effectiveness in compensation of voltage sags with different characteristics in an ungrounded neutral system. Based on a detailed analysis of the characteristics of voltage sags caused by different types of faults and the effect of the wiring mode of the transformer on these characteristics, the optimisation target of the reference voltage calculation is presented with several constraints. The reference voltages under all types of voltage sags are calculated by optimising the zero-sequence component, which can reduce the degree of swell in the phase-to-ground voltage after compensation to the maximum extent and can improve the symmetry degree of the output voltages of the DVR, thereby effectively increasing the compensation ability. The validity and effectiveness of the proposed method are verified by simulation and experimental results.

Voltage-Sharing Converter to Supply Single-Phase Asymmetrical Four-Level Diode-Clamped Inverter With High Power Factor Loads

DEFF Research Database (Denmark)

Boora, Arash A.; Nami, Alireza; Zare, Firuz

2010-01-01

The output voltage quality of some of the single-phase multilevel inverters can be improved when their dc-link voltages are regulated asymmetrically. Symmetrical and asymmetrical multilevel diode-clamped inverters have the problem of dc-link capacitor voltage balancing, especially when power factor...... that the proposed combination of introduced multioutput dc–dc converter and single-phase ADCI is a good candidate for power conversion in residential photovoltaic (PV) utilization....

Restrictions on TWT Helix Voltage Ripple for Acceptable Notch Filter Performance

Energy Technology Data Exchange (ETDEWEB)

Hyslop, B.

1984-12-01

An ac ripple on the helix voltage of the 1-2 GHz TWT's creates FM sidebands that cause amplitude and phase modulation of the microwave TWT output signal. A limit of 16 volts peak-to-peak is required for acceptable superconducting notch filter performance.

An AMOLED AC-Biased Pixel Design Compensating the Threshold Voltage and I-R Drop

Directory of Open Access Journals (Sweden)

Ching-Lin Fan

2011-01-01

Full Text Available We propose a novel pixel design and an AC bias driving method for active-matrix organic light-emitting diode (AM-OLED displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs. The proposed threshold voltage and I-R drop compensation circuit, which comprised three transistors and one capacitor, have been verified to supply uniform output current by simulation work using the Automatic Integrated Circuit Modeling Simulation Program with Integrated Circuit Emphasis (AIM-SPICE simulator. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<0.7% and low voltage drop of VDD power line. The proposed pixel circuit effectively enables threshold-voltage-deviation correction of driving TFT and compensates for the voltage drop of VDD power line using AC bias on OLED cathode.

Synchronised Voltage Space Vector Modulation for Three-level Inverters with Common-mode Voltage Elimination

DEFF Research Database (Denmark)

Oleschuk, Valentin; Blaabjerg, Frede

2002-01-01

A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...... of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...... advantages of synchronous PWM in comparison with asynchronous at low ratios between the switching frequency and fundamental frequency....

A novel sourceline voltage compensation circuit for embedded NOR flash memory

International Nuclear Information System (INIS)

Zhang Shengbo; Yang Guangjun; Hu Jian; Xiao Jun

2014-01-01

A novel sourceline voltage compensation circuit for program operation in embedded flash memory is presented. With the sourceline voltage compensation circuit, the charge pump can modulate the output voltage according to the number of cells to be programmed with data “0”. So the IR drop on the sourceline decoding path is compensated, and a stable sourceline voltage can be obtained. In order to reduce the power dissipation in program operation, a bit-inversion program circuit is adopted. By using the bit-inversion program circuit, the cells programmed to data “0” are limited to half of the bits of a write data word, thus power dissipation in program operation is greatly reduced. A 1.8-V 8 × 64-kbits embedded NOR flash memory employing the two circuits has been integrated using a GSMC 0.18-μm 4-poly 4-metal CMOS process. (semiconductor integrated circuits)

Nanosecond pulsed power generator for a voltage amplitude up to 300 kV and a repetition rate up to 16 Hz for fine disintegration of quartz

Energy Technology Data Exchange (ETDEWEB)

Krastelev, E. G., E-mail: ekrastelev@yandex.ru; Sedin, A. A.; Tugushev, V. I. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2015-12-15

A generator of high-power high-voltage nanosecond pulses is intended for electrical discharge disintegration of mineral quartz and other nonconducting minerals. It includes a 320 kV Marx pulsed voltage generator, a high-voltage glycerin-insulated coaxial peaking capacitor, and an output gas spark switch followed by a load, an electric discharge disintegration chamber. The main parameters of the generator are as follows: a voltage pulse amplitude of up to 300 kV, an output impedance of ≈10 Ω, a discharge current amplitude of up to 25 kA for a half-period of 80–90 ns, and a pulse repetition rate of up to 16 Hz.

Nanosecond pulsed power generator for a voltage amplitude up to 300 kV and a repetition rate up to 16 Hz for fine disintegration of quartz

International Nuclear Information System (INIS)

Krastelev, E. G.; Sedin, A. A.; Tugushev, V. I.

2015-01-01

A generator of high-power high-voltage nanosecond pulses is intended for electrical discharge disintegration of mineral quartz and other nonconducting minerals. It includes a 320 kV Marx pulsed voltage generator, a high-voltage glycerin-insulated coaxial peaking capacitor, and an output gas spark switch followed by a load, an electric discharge disintegration chamber. The main parameters of the generator are as follows: a voltage pulse amplitude of up to 300 kV, an output impedance of ≈10 Ω, a discharge current amplitude of up to 25 kA for a half-period of 80–90 ns, and a pulse repetition rate of up to 16 Hz

High-Voltage Clock Driver for Photon-Counting CCD Characterization

Science.gov (United States)

Baker, Robert

2013-01-01

A document discusses the CCD97 from e2v technologies as it is being evaluated at Goddard Space Flight Center's Detector Characterization Laboratory (DCL) for possible use in ultra-low background noise space astronomy applications, such as Terrestrial Planet Finder Coronagraph (TPF-C). The CCD97 includes a photoncounting mode where the equivalent output noise is less than one electron. Use of this mode requires a clock signal at a voltage level greater than the level achievable by the existing CCD (charge-coupled-device) electronics. A high-voltage waveform generator has been developed in code 660/601 to support the CCD97 evaluation. The unit generates required clock waveforms at voltage levels from -20 to +50 V. It deals with standard and arbitrary waveforms and supports pixel rates from 50 to 500 kHz. The system is designed to interface with existing Leach CCD electronics.

Low settings of the ventricular pacing output in patients dependent on a pacemaker: are they really safe?

Science.gov (United States)

Schuchert, Andreas; Frese, Jens; Stammwitz, Ekkehard; Novák, Miroslav; Schleich, Arthur; Wagner, Stefan M; Meinertz, Thomas

2002-06-01

It is generally acknowledged that pacemaker output must be adjusted with a 100% voltage safety margin above the pacing threshold to avoid ineffective pacing, especially in patients dependent on pacemakers. The aim of this prospective crossover study was to assess the beat-to-beat safety of low outputs in patients who are dependent on a pacemaker between 2 follow-up examinations. The study included 12 patients who had received a DDD pacemaker with an automatic beat-to-beat capture verification function. The ventricular output at 0.4 milliseconds pulse duration was programmed independently of the actual pacing threshold in a crossover randomization to 1.0 V, 1.5 V, and 2.5 V for 6 weeks each. At each follow-up, the diagnostic counters were interrogated and the pacing threshold at 0.4 milliseconds was determined in 0.1-V steps. The diagnostic pacemaker counters depict the frequency of back-up pulses delivered because of a loss of capture. During the randomization to 1.0-V output, we evaluated whether the adjustment of the output under consideration of the >100% voltage safety margin reduced the frequency of back-up pulses. Pacing thresholds at the randomization to 1.0-V, 1.5-V, and 2.5-V output were not significantly different, with 0.7 +/- 0.3 V at 2.5-V output, 0.6 +/- 0.2 V at 1.5-V output, and 0.6 +/- 0.2 V at 1.0-V output. The frequency of back-up pulses was similar at 2.5-V and 1.5-V output, 2.2% +/- 1.9% and 2.0% +/- 2.0%, respectively. The frequency of back-up pulses significantly increased at 1.0-V output to 5.8% +/- 6.4% (P 5% of the time between the 2 follow-ups were observed in no patient at 2.5 V, in 1 patient at 1.5 V, and in 5 patients at 1.0 V. At the randomization to the 1.0-V output, 6 patients had pacing thresholds of 0.5 V or less, and 6 patients had pacing thresholds >0.5 V. The frequency of back-up pulses in the 2 groups was not significantly different, 6.4% +/- 8.6% and 5.7% +/- 2.6%. The frequency of back-up pulses was significantly higher at 1

Tunable First-Order Resistorless All-Pass Filter with Low Output Impedance

Directory of Open Access Journals (Sweden)

Parveen Beg

2014-01-01

Full Text Available This paper presents a voltage mode cascadable single active element tunable first-order all-pass filter with a single passive component. The active element used to realise the filter is a new building block termed as differential difference dual-X current conveyor with a buffered output (DD-DXCCII. The filter is thus realized with the help of a DD-DXCCII, a capacitor, and a MOS transistor. By exploiting the low output impedance, a higher order filter is also realized. Nonideal and parasitic study is also carried out on the realised filters. The proposed DD-DXCCII filters are simulated using TSMC the 0.25 µm technology.

Tunable first-order resistorless all-pass filter with low output impedance.

Science.gov (United States)

Beg, Parveen

2014-01-01

This paper presents a voltage mode cascadable single active element tunable first-order all-pass filter with a single passive component. The active element used to realise the filter is a new building block termed as differential difference dual-X current conveyor with a buffered output (DD-DXCCII). The filter is thus realized with the help of a DD-DXCCII, a capacitor, and a MOS transistor. By exploiting the low output impedance, a higher order filter is also realized. Nonideal and parasitic study is also carried out on the realised filters. The proposed DD-DXCCII filters are simulated using TSMC the 0.25 µm technology.

New series half-bridge converters with the balance input split capacitor voltages

Science.gov (United States)

Lin, Bor-Ren; Chiang, Huann-Keng; Wang, Shang-Lun

2016-03-01

This article presents a new dc/dc converter to perform the main functions of zero voltage switching (ZWS), low converter size, high switching frequency and low-voltage stress. Metal-oxide-semiconductor field-effect transistors (MOSFETs) with high switching frequency are used to reduce the converter size and increase circuit efficiency. To overcome low-voltage stress and high turn-on resistance of MOSFETs, the series half-bridge topology is adopted in the proposed converter. Hence, the low-voltage stress MOSFETs can be used for medium-input voltage applications. The asymmetric pulse-width modulation is used to generate the gating signals and achieve the ZWS. On the secondary side, the parallel connection of two diode rectifiers is adopted to reduce the current rating of passive components. On the primary side, the series connection of two transformers is used to balance two output inductor currents. Two flying capacitors are used to automatically balance the input split capacitor voltages. Finally, experiments with 1000 W rated power are performed to verify the theoretical analysis and the effectiveness of proposed converter.

Improved detection of electrical activity with a voltage probe based on a voltage-sensing phosphatase.

Science.gov (United States)

Tsutsui, Hidekazu; Jinno, Yuka; Tomita, Akiko; Niino, Yusuke; Yamada, Yoshiyuki; Mikoshiba, Katsuhiko; Miyawaki, Atsushi; Okamura, Yasushi

2013-09-15

  One of the most awaited techniques in modern physiology is the sensitive detection of spatiotemporal electrical activity in a complex network of excitable cells. The use of genetically encoded voltage probes has been expected to enable such analysis. However, in spite of recent progress, existing probes still suffer from low signal amplitude and/or kinetics too slow to detect fast electrical activity. Here, we have developed an improved voltage probe named Mermaid2, which is based on the voltage-sensor domain of the voltage-sensing phosphatase from Ciona intestinalis and Förster energy transfer between a pair of fluorescent proteins. In mammalian cells, Mermaid2 permits ratiometric readouts of fractional changes of more than 50% over a physiologically relevant voltage range with fast kinetics, and it was used to follow a train of action potentials at frequencies of up to 150 Hz. Mermaid2 was also able to detect single action potentials and subthreshold voltage responses in hippocampal neurons in vitro, in addition to cortical electrical activity evoked by sound stimuli in single trials in living mice.