High-Efficiency Operating Modes for Isolated Piezoelectric-Transformer-Based DC-DC Converters

2020 ◽  
Author(s):  
Jessica D. Boles ◽  
Elaine Ng ◽  
Jeffrey H. Lang ◽  
David J. Perreault
Keyword(s):  
High Efficiency ◽  
Piezoelectric Transformer ◽  
Operating Modes

scholarly journals Octane Index Applicability over the Pressure-Temperature Domain

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Tommy R. Powell ◽  
James P. Szybist ◽  
Flavio Dal Forno Chuahy ◽  
Scott J. Curran ◽  
John Mengwasser ◽  
...  
Keyword(s):  
High Efficiency ◽  
National Laboratory ◽  
Operating Conditions ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Oak Ridge ◽  
Operating Modes ◽  
Wide Range ◽  
Thermodynamic Conditions ◽  
Si Engines

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.

scholarly journals A Modified High Voltage Gain SEPIC Based DC-DC Converter with Continuous Conduction Mode

2020 ◽  
Vol 6 (12) ◽  
pp. 268-274
Author(s):  
G.Vijaykumar and Dr.V.Geetha
Keyword(s):  
High Voltage ◽  
High Efficiency ◽  
Input Voltage ◽  
Voltage Gain ◽  
Pv System ◽  
Operating Modes ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
High Output Voltage ◽  
High Output

A high voltage gain modified SEPIC converter is proposed in this paper. This proposed converter has many advantages i.e., high output voltage, lower voltage stress, high efficiency, voltage gain is high without any coupled inductor and transformer, continuous input current. Thus, there is no overshoot voltage at turn-off process for switches. By using single switches, the CCM mode operation can be easily controlled by this converter, so control system is simple and also wide output values is obtained only by modifying the duty cycle. This modified converter has lower components than conventional converter. The operating modes and design of modified converter are discussed. The output power of this converter is 6 watts. By this converter, this converter capable of developing the two and half times of input voltage. The PV system also used this converter to develop high voltage gain. This high voltage gain is achieved by using MATLAB/SIMULIMK platform.

scholarly journals Online parallel accumulation − serial fragmentation (PASEF) with a novel trapped ion mobility mass spectrometer

2018 ◽  
Author(s):  
Florian Meier ◽  
Andreas-David Brunner ◽  
Scarlet Koch ◽  
Heiner Koch ◽  
Markus Lubeck ◽  
...  
Keyword(s):  
Cross Sections ◽  
Ion Mobility ◽  
Large Scale ◽  
High Efficiency ◽  
Low Voltage ◽  
Shotgun Proteomics ◽  
Trapped Ion ◽  
Operating Modes ◽  
Third Dimension ◽  
Mobility Device

ABSTRACTIn bottom-up proteomics, peptides are separated by liquid chromatography with elution peak widths in the range of seconds, while mass spectra are acquired in about 100 microseconds with time-of-fight (TOF) instruments. This allows adding ion mobility as a third dimension of separation. Among several formats, trapped ion mobility spectrometry (TIMS) is attractive due to its small size, low voltage requirements and high efficiency of ion utilization. We have recently demonstrated a scan mode termed parallel accumulation – serial fragmentation (PASEF), which multiplies the sequencing speed without any loss in sensitivity (Meier et al., PMID: 26538118). Here we introduce the timsTOF Pro instrument, which optimally implements online PASEF. It features an orthogonal ion path into the ion mobility device, limiting the amount of debris entering the instrument and making it very robust in daily operation. We investigate different precursor selection schemes for shotgun proteomics to optimally allocate in excess of 100 fragmentation events per second. More than 800,000 fragmentation spectra in standard 120 min LC runs are easily achievable, which can be used for near exhaustive precursor selection in complex mixtures or re-sequencing weak precursors. MaxQuant identified more than 6,400 proteins in single run HeLa analyses without matching to a library, and with high quantitative reproducibility (R > 0.97). Online PASEF achieves a remarkable sensitivity with more than 2,900 proteins identified in 30 min runs of only 10 ng HeLa digest. We also show that highly reproducible collisional cross sections can be acquired on a large scale (R > 0.99). PASEF on the timsTOF Pro is a valuable addition to the technological toolbox in proteomics, with a number of unique operating modes that are only beginning to be explored.

scholarly journals High Efficiency Buck-Boost Converter with Three Modes Selection for HV Applications using 0.18 μm Technology

2020 ◽  
Vol 18 (2) ◽  
pp. 137-144
Author(s):  
Fouad Farah ◽  
Mustapha El Alaoui ◽  
Abdelali El Boutahiri ◽  
Mounir Ouremchi ◽  
Karim El Khadiri ◽  
...  
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Output Voltage ◽  
High Efficiency ◽  
Power Conversion ◽  
Boost Converter ◽  
Current Control ◽  
Voltage Range ◽  
Operating Modes ◽  
Soft Start

In this paper, we aim to make a detailed study on the evaluation and the characteristics of the non-inverting buck–boost converter. In order to improve the behaviour of the buck-boost converter for the three operating modes, we propose an architecture based on peak current-control. Using a three modes selection circuit and a soft start circuit, this converter is able to expand the power conversion efficiency and reduce inrush current at the feedback loop. The proposed converter is designed to operate with a variable output voltage. In addition, we use LDMOS transistors with low on-resistance, which are adequate for HV applications. The obtained results show that the proposed buck-boost converter perform perfectly compared to others architecture and it is successfully implemented using 0.18 μm CMOS TSMC technology, with an output voltage regulated to 12V and input voltage range of 4-20 V. The power conversion efficiency for the three operating modes buck, boost and buck-boost are 97.6%, 96.3% and 95.5% respectively at load current of 4A.

STEAM: A Mobile Hydraulic System With Engine Integration

2013 ◽  
Author(s):  
Milos Vukovic ◽  
Sebastian Sgro ◽  
Hubertus Murrenhoff
Keyword(s):  
Hydraulic System ◽  
High Efficiency ◽  
Combustion Engine ◽  
Low Cost ◽  
Total System ◽  
Hydraulic Systems ◽  
Pressure System ◽  
Operating Modes ◽  
Hydraulic Design ◽  
Displacement Pump

In recent years, research institutions worldwide have developed a number of new mobile hydraulic systems. Despite their improved energy efficiency, these systems have yet to gain market acceptance due to their related increase in component costs and decrease in robustness. At the Institute for Fluid Power Drives and Controls in Aachen, a new system for mobile machines, named STEAM (Steigerung der Energieeffizienz in der Arbeitshydraulik mobiler Arbeitsmaschinen), is being developed using inexpensive off-the-shelf components. The aim is to improve the total system efficiency by considering all the subsystems in the machine. This is done by integrating the internal combustion engine (ICE) into the hydraulic design process. By using a constant pressure system in combination with a low-cost fixed displacement pump the hydraulic system is designed to ensure the ICE experiences a constantly high load in a region of high efficiency, so-called point operation. To decrease the hydraulic losses incurred when supplying the linear actuators with flow, an additional intermediate pressure rail with independent metering edges is used. This enables various energy efficient discrete operating modes, including energy regeneration and recuperation.

Design, Simulation, and Implementation of an Electric Hybrid Motorcycle

2010 ◽  
Author(s):  
Behzad Asaei ◽  
Seyed Hosein Seyed mohammadi ◽  
Aghil Yousefi koma ◽  
Mahdi Habibidoost ◽  
Roohollah Aghnoot ◽  
...  
Keyword(s):  
Control Strategy ◽  
High Efficiency ◽  
Power Transmission ◽  
Combustion Engine ◽  
Front Wheel ◽  
Bldc Motor ◽  
Brushless Dc ◽  
Operating Modes ◽  
Proposed Model ◽  
Variable Transmission

This paper presents a general integrated procedure of fabricating a Hybrid Electric Motorcycle (HEM). Firstly, a simple model designed and simulated using ADVISOR2002 and the proposed model is exported to MATLAB/SIMULINK. Secondly, the controller schematic and its optimized control strategy are described. In addition, the ratings of the components including the batteries, electric motor, and internal combustion engine (ICE) are calculated based on the design. A 125 cc ICE motorcycle is selected for conversion to HEM. A brushless DC (BLDC) motor assembled in front wheel as accessory propellant. The nominal powers are 8.2 kW at 8500 rpm and 500 W for the ICE and BLDC respectively. The original motorcycle has a Continues Variable Transmission (CVT) that is the best choice for the HEM power transmission because it can operate in automatic handling mode and has high efficiency. Moreover, by using CVT the ICE can be started while it is running at 15 km/h. Finally, the three operating modes of the HEM, the servo motors, and the LCD panel were explained.

Coaxial cavity vircator with enhanced efficiency

2008 ◽  
Vol 74 (2) ◽  
pp. 233-244 ◽  
Author(s):  
G.Z. LIU ◽  
H. SHAO ◽  
Z.F. YANG ◽  
Z.M. SONG ◽  
C.H. CHEN ◽  
...  
Keyword(s):  
Power Efficiency ◽  
High Efficiency ◽  
Virtual Cathode ◽  
Coaxial Cavity ◽  
High Power Microwave ◽  
Operating Modes ◽  
Power And Energy ◽  
Designing Method ◽  
Power Microwave ◽  
Good Agreement

AbstractA vircator with a coaxial cavity has the potential to increase the beam–microwave conversion efficiency. According to the E-field distribution pattern of the modes in the anode cavity of a coaxial vircator, the resonant frequency band of the injected electron beam and the lowest two operating modes are derived. The main frequency of the virtual cathode is also deduced. The optimal operating frequency and high-efficiency designing method of a coaxial cavity vircator is discussed. An experimental setup is designed and built to test the high-power microwave (HPM) generation mechanism described by theoretical analysis as well as increase the power efficiency. HPM frequency obtained in the experiment is in good agreement with the analysis. The power and energy efficiencies obtained in the experiment are, respectively, 8.7% and 6.8% with 50 ns pulse width. Frequency and phase stable HPM radiation is observed as well as pulse shortening is evidently depressed.

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