Digital Feed-Forward Control of Gas Mixture With High-Speed Valve Switching

Volume 3: Manufacturing Equipment and Systems ◽

10.1115/msec2018-6388 ◽

2018 ◽

Author(s):

Christopher R. Martin ◽

Todd D. Batzel

Keyword(s):

Flow Rate ◽

High Speed ◽

Gas Flow ◽

Pulse Width Modulation ◽

Modulation Scheme ◽

Switching Frequency ◽

Gas Mixture ◽

Constant Flow Rate ◽

Feed Forward Control ◽

Flow Rate Control

To address a need for digital gas mixture control, this paper presents a valve design for digital gas flow rate control without a feedback measurement. This design uses a transonic nozzle to regulate a constant flow rate with partial pressure recovery and a pulse-width modulation scheme to actuate flow rate without needing precise location of a throttle body. Experimental results from a prototype are presented showing linear variation of flow with respect to duty cycle and switching frequency consistent with the valve’s theory of operation. Outliers are especially prominant as frequency is varied, and are believed to be due to acoustic effects in the supply line.

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Experimental validation of new self-voltage balanced 9L-ANPC inverter for photovoltaic applications

Scientific Reports ◽

10.1038/s41598-021-84531-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

M. Jagabar Sathik ◽

Dhafer J. Almakhles ◽

N. Sandeep ◽

Marif Daula Siddique

Keyword(s):

Output Voltage ◽

Pulse Width Modulation ◽

Superior Performance ◽

Modulation Scheme ◽

Switching Frequency ◽

Switched Capacitor ◽

Renewable Energy Resources ◽

High Quality ◽

Multilevel Inverters ◽

Blocking Voltage

AbstractMultilevel inverters play an important role in extracting the power from renewable energy resources and delivering the output voltage with high quality to the load. This paper proposes a new single-stage switched capacitor nine-level inverter, which comprises an improved T-type inverter, auxiliary switch, and switched cell unit. The proposed topology effectively reduces the DC-link capacitor voltage and exhibits superior performance over recently switched-capacitor inverter topologies in terms of the number of power components and blocking voltage of the switches. A level-shifted multilevel pulse width modulation scheme with a modified triangular carrier wave is implemented to produce a high-quality stepped output voltage waveform with low switching frequency. The proposed nine-level inverter’s effectiveness, driven by the recommended modulation technique, is experimentally verified under varying load conditions. The power loss and efficiency for the proposed nine-level inverter are thoroughly discussed with different loads.

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Influence of the Variation of Plasma Torch Parameters on Particle Melting and Solidification

Thermal Spray 1997: Proceedings from the United Thermal Spray Conference ◽

10.31399/asm.cp.itsc1997p0535 ◽

1997 ◽

Author(s):

M. Vardelle ◽

P. Fauchais ◽

A. Vardelle ◽

A.C. Léger

Keyword(s):

Flow Rate ◽

High Speed ◽

Gas Flow ◽

Operating Conditions ◽

Characteristic Parameters ◽

Powder Mass ◽

Arc Current ◽

Plasma Sprayed ◽

Carrier Gas Flow ◽

Melting And Solidification

Abstract A study of the flattening and cooling of particles plasma-sprayed on a substrate is presented. The characteristic parameters of the splats are linked to the parameters of the impacting particles by using an experimental device consisting of a phase Doppler particle analyzer and a high-speed pyrometer. However, during the long experiments required to get reliable correlations, it was observed that variations in plasma spray operating conditions may alter the particles behavior in the plasma jet. Therefore, a simple and easy-to-use system was developed to control in real time the spray jet. In this paper, the effect of carrier gas flow rate, arc current and powder mass flow rate is investigated. The results on zirconia and alumina powders show the capability of the technique to sense the particle spray position and width.

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Fabrication of Rheological Material by Rotating Gas Bubble Stirring

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.1573 ◽

2011 ◽

Vol 239-242 ◽

pp. 1573-1576 ◽

Cited By ~ 1

Author(s):

Lei Zhang ◽

Xuan Pu Dong ◽

Wen Jun Wang ◽

Rong Ma ◽

Ke Li ◽

...

Keyword(s):

Flow Rate ◽

Gas Flow ◽

Rotation Speed ◽

Gas Bubble ◽

Gas Flow Rate ◽

Control Functions ◽

Stirring Effect ◽

Strong Convection ◽

Semi Solid ◽

Flow Rate Control

A rotating gas bubble stirring technique with specially designed equipment has been developed for the production of light alloy semi-solid slurry. The equipment was specially designed to have temperature, rotation speed and gas flow rate control functions. An Al-Si aluminum alloy was applied as the experimental material. The results showed that large volume of semi-solid slurry could be achieved with the actual stirring temperature of 4 °C to 20 °C below the liquidus temperature of the alloy, and the rotation speed of 195 r/min, and the gas flow rate of 2 L/min. A strong convection and weak stirring effect which was induced by the rotating gas bubbles in the melt was founded responsible for the formation of the semi-solid slurry.

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Research on collaborative control of double-plunger gas prover based on EtherCAT

Thermal Science ◽

10.2298/tsci191022002x ◽

2020 ◽

Vol 24 (5 Part A) ◽

pp. 2667-2687

Author(s):

Zhipeng Xu ◽

Feipeng Xu ◽

Dailiang Xie

Keyword(s):

Flow Rate ◽

High Speed ◽

Gas Flow ◽

Control Unit ◽

External Diameter ◽

Piston Cylinder ◽

Collaborative Control ◽

Critical Nozzles ◽

Parallel Mode ◽

Working Principle

Piston prover has been widely used as a gas flow standard for its advantages of high accuracy in standard volume, flow stability and repeatability. It has also been employed as the primary gas flow standard in many countries to calibrate meters. However, it is difficult to ensure the uniformity of the inside dimension of the piston, thus the application of conventional piston provers are limited by the maximum calibration flow generated by the piston cylinder volume. In this paper, an improved piston gas prover that mainly consists of two uniform plungers was proposed. Their external diameter constitutes the flow standard. The plungers are driven by servo motor, and the high speed fieldbus EtherCAT has been introduced as the control unit. Hence the two pistons could work collaboratively and operate in three modes: single-piston mode, double-pistons parallel mode, and double-pistons reciprocating mode. Besides generating steady-flow rate, the double-plunger prover can even produce an unsteady-flow rate which could be used to research the dynamic characteristics of flow meters. The structure and working principle of the three modes were carefully introduced. Then experiments for calibrating critical nozzles were carried out, and the results show that the repeatability of the discharge coefficient could be better than 0.06%, and the pressure fluctuation during the process was less than 50 Pa.

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Application of Constant Flow Rate Control Valve in Pump Discharge Regulation

Journal of Irrigation and Drainage Engineering ◽

10.1061/(asce)ir.1943-4774.0001393 ◽

2019 ◽

Vol 145 (7) ◽

pp. 06019005 ◽

Cited By ~ 1

Author(s):

Soheil Atashparvar ◽

Mohammad Bijankhan ◽

Ali Mahdavi Mazdeh

Keyword(s):

Flow Rate ◽

Rate Control ◽

Control Valve ◽

Constant Flow ◽

Constant Flow Rate ◽

Discharge Regulation ◽

Flow Rate Control

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Design of a Crank-Slider Spool Valve for Switch-Mode Circuits With Experimental Validation

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4038537 ◽

2017 ◽

Vol 140 (6) ◽

Cited By ~ 1

Author(s):

Shaun E. Koktavy ◽

Alexander C. Yudell ◽

James D. Van de Ven

Keyword(s):

Flow Rate ◽

High Speed ◽

Experimental Validation ◽

Viscous Friction ◽

Transition Time ◽

Switching Frequency ◽

Experimental Demonstration ◽

High Switching Frequency ◽

Switch Mode ◽

Spool Valve

A challenge in realizing switch-mode hydraulic circuits is the need for a high-speed valve with fast transition time and high switching frequency. The work presented includes the design and modeling of a suitable valve and experimental demonstration of the prototype in a hydraulic boost converter. The design consists of two spools driven by crank-sliders, designed for 120 Hz maximum switching frequency at a flow rate of 22.7 lpm. The fully open throttling loss is designed for <2% of the rated pressure of 34.5 MPa. The transition time is less than 5% (0.42 ms at 120 Hz) of the total cycle and the duty cycle is adjustable from 0 to 1. Leakage and viscous friction losses in the design are less than 2% of the rated hydraulic energy per cycle. The experimental results agreed well with the model resulting in a 3% variation in transition time. The use of the high-speed valve in a pressure boosts converter demonstrated boost ratio capabilities of 1.08–2.06.

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High-Power Multimodular Matrix Converters and Modulation

10.32920/ryerson.14648358.v1 ◽

2021 ◽

Author(s):

Jiacheng Wang

Keyword(s):

High Power ◽

Pulse Width Modulation ◽

Low Voltage ◽

Input Voltage ◽

Duty Ratio ◽

Modulation Scheme ◽

Switching Frequency ◽

Space Vector ◽

Phase Switching ◽

Matrix Converters

High-power multimodular matrix converters (MMMCs) comprising multiple threephase to single-phase matrix converter modules have emerged as a viable topology candidate for medium-voltage adjustable speed drives. As a combination of direct power conversion and cascaded multilevel structure, the MMMCs inherit features such as elimination of dc capacitors, four quadrant operation capability, employment of lowvoltage devices only, and superior output waveform quality under a limited device switching frequency. Due to their particular topological structure, modulation scheme design for the MMMCs is not straightforward and complicated. The presented work is mainly focused on development of suitable modulation schemes for the MMMCs. Several viable schemes as well as their corresponding switching patterns are proposed and verified by both simulation and experimental results. In order for the MMMCs to produce sinusoidal waveforms at both input and output ac terminals, a direct transfer matrix based modulation scheme is presented. It is revealed that a suitable modulation strategy for the MMMCs should aim at fabricating the total input current on the primary side of the isolation transformer. For topologies with more than two modules in cascade on each output phase, switching period displacement is necessary among modules to generate multilevel output waveforms. An indirect space vector based modulation scheme for the MMMCs is developed. With a few presumptions satisfied and viewed from a certain perspective, the MMMCs can still be modeled indirectly and be divided into fictitious rectifier and inverter stages. Therefore, space vector modulation methods can be independently applied to both stages for duty ratio calculation, before the results are converted and combined for determining per-phase output pulses. A new output switching pattern providing improved harmonic performance is also proposed. A novel modulation scheme based on diode rectifier emulation and phase-shifted sinusoidal pulse-width modulation is proposed. The method sacrifices input power factor adjustment, but enables the use of an indirect module construction leading to significantly reduced device count and complexity. Strategy for reducing additional switchings caused by input voltage ripples is also implemented and explained. In addition to simulation verifications, all the proposed schemes are further tested experimentally on a low-voltage prototype built in the lab. Details about the prototype implementation are introduced.

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Compression Technology Selection for Downhole Application in Gas Wells

Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2019-90854 ◽

2019 ◽

Author(s):

Ameen Malkawi ◽

Ahmed AlAdawy ◽

Rajesh Kumar V. Gadamsetty ◽

Rafael Lastra Melo

Keyword(s):

Flow Rate ◽

High Speed ◽

Gas Flow ◽

Optimal Solution ◽

Operating Conditions ◽

Technology Selection ◽

Well Performance ◽

Ambient Conditions ◽

Gas Wells ◽

Selection For

Abstract Downhole gas compression technology is an artificial lift method that aims to boost production, maximize recovery and delay onset of liquid loading in gas wells. There are different available compression technologies that can be considered for downhole applications, such as screw, scroll, centrifugal and axial compressors. Selection of the appropriate type mainly depends on expected well performance, ambient conditions, compressor operating envelope, technology characteristics, limitations and size constraints. The objective of this study is to perform a feasibility evaluation of compression solutions applicable for a given set of candidate gas wells. Aerodynamic and hydraulic models are used to determine operating conditions, compressor performance, and to select equipment specifications such as impeller diameter, compressor envelope, shaft HP requirement and number of stages among other parameters. A Pugh analysis is performed for all compression technologies and their characteristics to down-select the most suitable solutions for the given set of wells. The results of the analysis indicated an optimal downhole compression technology that covers most of the gas flow rate requirements and meet the performance expectations. The study also provided critical specifications for the compressor, including high-speed operation needed to provide the required flow rates and compression ratio for a relatively small housing diameter. The study also finds that other technologies may be applicable but only to certain population of wells, as the flow rate spectrum is narrower than the optimal solution at the studied conditions. The analysis for the discarded compression technologies in this study showed relatively significant disadvantages for downhole application when compared to the selected compressor. This study presents a holistic analysis for compression technology selection for gas wells that, as per to the understanding of the authors, is unique in the existing literature of gas well applications.

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