scholarly journals Design of an universal source for semi-automatic ac welding and induction heating

2021 ◽  
Vol 6 (1 (114)) ◽  
pp. 38-46
Author(s):  
Vladimir Burlaka ◽  
Elena Lavrova ◽  
Svetlana Podnebennaya ◽  
Vitaliy Ivanov ◽  
Serhii Burikov
Keyword(s):  
Induction Heating ◽  
Power Factor ◽  
Distinctive Feature ◽  
Source Control ◽  
Stable Operation ◽  
Technical Solution ◽  
Automatic Welding ◽  
Feed Drive ◽  
Wide Range ◽  
Small Parts

This paper proposes a circuit solution and a power source control algorithm for semi-automatic AC welding with improved energy and weight-size characteristics. A distinctive feature of the designed source is the absence of an input rectifier: welding is carried out with a high-frequency alternating current. That has made it possible to significantly reduce power losses in the source, as well as provide the possibility of implementing induction heating by connecting an inductor to the source output. Another distinctive feature of the designed source is an increased power factor and a reduced level of higher harmonics of the current consumed. The power factor of the described source reaches 0.94 against 0.5÷0.7 for sources equipped with a conventional rectifier with capacitive smoothing. The designed source's composition includes a power supply system for the wire feed drive with speed stabilization due to positive feedback on the motor current. That has made it possible to ensure the stable operation of the drive in a wide range of speeds. A model has also been developed of a flux wire welding torch containing a feed drive and a coil with a wire (up to 100 mm in diameter), placed, in order to reduce the size, in the handle of the torch. In addition to the welding function, the source makes it possible to solve the tasks related to induction heating and/or hardening of small parts; to that end, a compact inductor is connected to its output. Tests of the source showed the feasibility of the proposed ideas and circuit solutions. The dimensions of the source are 190×107×65 mm; weight, 1.4 kg; output current, up to 120 A. The proposed technical solution enables the construction of small-sized, lightweight, universal, easy-to-use power supplies for semi-automatic welding with the option of induction heating

scholarly journals Features stabilization of the consumer current using electro-ferromagnetic circuits

2019 ◽  
Vol 139 ◽  
pp. 01075 ◽  
Author(s):  
G.R. Rafikova ◽  
M.R. Ruzinazarov ◽  
S.K. Makhmutkhonov
Keyword(s):  
Power Factor ◽  
Distinctive Feature ◽  
Input Voltage ◽  
Load Resistance ◽  
Curve Shape ◽  
Paramagnetic Resonance ◽  
Wide Range ◽  
Electron Microscopes ◽  
Very High ◽  
Amplitude Characteristics

Electromagnetic ferromagnetic oscillatory circuits having falling sections on the amplitude characteristics formed the basis of stabilizers based on the principle of summing the currents of individual branches. A distinctive feature of such stabilizers is that the current remains unchanged both when the load resistance changes, so when the input voltage varies over a wide range. This is required by devices such as electromagnets of physical instruments, electromagnetic lenses of electron microscopes, instruments for emitting nuclear paramagnetic resonance, instruments and devices of various automation schemes, measuring and computing equipment, as well as many electrotechnological processes. Therefore, current stabilization has long attracted the attention of many researchers, and this is still one of the important problems of electrical engineering. The curve shape of the proposed current stabilizer is close to a sinusoid, the power factor is very high, since the device operates in capacitive mode.

scholarly journals Research on Zero-Voltage Ride Through Control Strategy of Doubly Fed Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2287
Author(s):  
Kaina Qin ◽  
Shanshan Wang ◽  
Zhongjian Kang
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Control Strategy ◽  
Large Scale ◽  
Sliding Mode ◽  
Stable Operation ◽  
Wide Range ◽  
Dc Bus ◽  
Doubly Fed ◽  
Zero Voltage

With the rapid increase in the proportion of the installed wind power capacity in the total grid capacity, the state has put forward higher and higher requirements for wind power integration into the grid, among which the most difficult requirement is the zero-voltage ride through (ZVRT) capability of the wind turbine. When the voltage drops deeply, a series of transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur in the motor, which will seriously endanger the safe operation of the wind turbine itself and its control system, and cause large-scale off-grid accident of wind generator. Therefore, it is of great significance to improve the uninterrupted operation ability of the wind turbine. Doubly fed induction generator (DFIG) can achieve the best wind energy tracking control in a wide range of wind speed and has the advantage of flexible power regulation. It is widely used at present, but it is sensitive to the grid voltage. In the current study, the DFIG is taken as the research object. The transient process of the DFIG during a fault is analyzed in detail. The mechanism of the rotor overcurrent and DC bus overvoltage of the DFIG during fault is studied. Additionally, the simulation model is built in DIgSILENT. The active crowbar hardware protection circuit is put into the rotor side of the wind turbine, and the extended state observer and terminal sliding mode control are added to the grid side converter control. Through the cooperative control technology, the rotor overcurrent and DC bus overvoltage can be suppressed to realize the zero-voltage ride-through of the doubly fed wind turbine, and ensure the safe and stable operation of the wind farm. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy.

Electrodeposited Thin Conformal TiO2 Coating Enabling Stable Operation of BiVO4 Photoanodes in Basic Media

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1917-1917
Author(s):  
Dongho Lee ◽  
Kyoung-Shin Choi
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Synthesis Method ◽  
Protective Layer ◽  
Photoelectrochemical Cell ◽  
Semiconductor Surface ◽  
Stable Operation ◽  
Solar Water Splitting ◽  
Wide Range ◽  
Basic Solutions

Producing hydrogen via solar water splitting using a photoelectrochemical cell (PEC) persists as one of the most exciting research topics in the field of solar fuels. The construction of efficient PECs requires the integration of multiple components including a photoanode, a photocathode, an oxygen evolution catalyst, and a hydrogen evolution catalyst. Therefore, the compatibility and stability of all of these elements in a given operating condition are crucial. When the stability of a semiconductor electrode used as the photoanode or photocathode is limited in an acidic or basic condition which is optimum for the operation of the other components, a thin protective layer has been deposited on the semiconductor surface to prevent its chemical dissolution. Surface coating of a thin and conformal TiO2 layer has been proven to be successful for protecting photoelectrodes since TiO2 is chemically and electrochemically stable in a wide range of pH conditions under both anodic and cathodic conditions. In order to prevent the semiconductor surface from coming into direct contact with the corrosive electrolyte, complete coverage of the photoelectrode with TiO2 is required. At the same time, the TiO2 layer should be thin enough not to interfere with the charge transport properties of the photoelectrode. As a result, atomic layer deposition (ALD) has been the only successful tool used to date to produce an effective protective layer. However, the slow processing time and economic viability of ALD methods motivated us to develop an inexpensive and facile solution-based synthesis method for the deposition of high quality TiO2 coating layers. In this presentation, we report a new electrochemical method to deposit a thin and conformal TiO2 layer on nanoporous BiVO4 that has an intricate, high surface area morphology. BiVO4 is a promising n-type photoanode material with a relatively low bandgap (2.4~2.5 eV). However, its usage has been limited to neutral and mildly basic conditions (pH 5~9) because it is chemically unstable in strongly acidic and basic conditions. Our method allows for the deposition of a 5~6 nm thick TiO2 layer on BiVO4 within 1 min and the resulting BiVO4/TiO2 electrodes exhibit chemical stability in basic solutions (pH 12~13). Sulfite oxidation measurements of BiVO4 and BiVO4/TiO2 electrodes show that the thin TiO2 protective layer does not significantly reduce the hole transfer to the electrolyte. Finally, we demonstrate the photoelectrochemical stability of the BiVO4/TiO2 electrode for photoelectrochemical water oxidation in basic solutions by coupling the BiVO4/TiO2 electrode with appropriate oxygen evolution catalysts.

Influence of operating conditions on population dynamics in nitrifying biofilms

1999 ◽  
Vol 39 (7) ◽  
pp. 5-11 ◽  
Author(s):  
Valentina Lazarova ◽  
Danièle Bellahcen ◽  
Jacques Manem ◽  
David A. Stahl ◽  
Bruce E. Rittmann
Keyword(s):  
Population Dynamics ◽  
Ammonia Oxidation ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Stable Operation ◽  
N Removal ◽  
Wide Range ◽  
Total Nitrogen Removal ◽  
Nitrite Oxidizers

TURBO N® is a circulating-bed biofilm reactor that provides stable operation and high N removal for a wide range of N and BOD loadings. This paper describes the influence of operating conditions on biofilm composition and population dynamics when the TURBO N® is operated to achieve tertiary nitrification, simultaneous carbon and ammonia oxidation and total nitrogen removal when coupled with a pre-denitrification fixed floating bed reactor. In situ specific nitrification rates and respiration tests showed that ammonium and nitrite oxidizers became less active in the biofilm once oxidation of influent BOD became important. Analyses of community structure with oligonucleotide probes targeted to the 16S rRNA showed the same general trends for nitrifiers, but also suggested shifts in the makeup of the ammonium and nitrite oxidizers that could not be detected with respirometry or specific nitrification rates.

scholarly journals Self-Power Dynamic Sensor Based on Triboelectrification for Tilt of Direction and Angle

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2384 ◽  
Author(s):  
Hyeonhee Roh ◽  
Inkyum Kim ◽  
Jinsoo Yu ◽  
Daewon Kim
Keyword(s):  
Electrical Power ◽  
Stable Operation ◽  
Huge Number ◽  
Channel System ◽  
Active Sensor ◽  
Electrostatic Induction ◽  
Wide Range ◽  
Self Powered ◽  
The Internet Of Things ◽  
Great Development

With the great development of the Internet of Things (IoT), the use of sensors have increased rapidly because of the importance in the connection between machines and people. A huge number of IoT sensors consume vast amounts of electrical power for stable operation and they are also used for a wide range of applications. Therefore, sensors need to operate independently, sustainably, and wirelessly to improve their capabilities. In this paper, we propose an orientation and the tilt triboelectric sensor (OT-TES) as a self-powered active sensor, which can simultaneously sense the tilting direction and angle by using the two classical principles of triboelectrification and electrostatic induction. The OT-TES device consists of a rectangular acrylic box containing polytetrafluoroethylene (PTFE) balls moved by gravity. The output voltage and current were 2 V and 20 nA, respectively, with a PTFE ball and Al electrode. The multi-channel system was adopted for measuring the degree and direction of tilt by integrating the results of measured electrical signals from the eight electrodes. This OT-TES can be attached on the equipment for drones or divers to measure their stability. As a result, this proposed device is expected to expand the field of TES, as a sensor for sky and the underwater.

scholarly journals Methods for controlling the elastic damping characteristics of pneumatic seat suspensions

2021 ◽  
Vol 1 (2) ◽  
pp. 27-33
Author(s):  
M.V. Lyashenko ◽  
◽  
V.V. Shekhovtsov ◽  
P.V. Potapov ◽  
A.I. Iskaliyev ◽  
...  
Keyword(s):  
Vibrational Energy ◽  
Working Fluid ◽  
Technical Solution ◽  
Technical Literature ◽  
Seat Suspension ◽  
Suspension Systems ◽  
Damping Characteristics ◽  
Air Suspension ◽  
Wide Range ◽  
Vehicle Seat

The pneumatic seat suspension is one of the most important, and in some situations, one of the key components of the vibration protection system for the human operator of the vehicle. At the present stage of scientific and technical activities of most developers, great emphasis is placed on controlled seat suspension systems, as the most promising systems. This article analyzes the methods of controlling the elastic damping characteristics of the air suspension of a vehicle seat. Ten dif-ferent and fairly well-known methods of changing the shape and parameters of elastic damping characteristics due to electro-pneumatic valves, throttles, motors, additional cavities, auxiliary mechanisms and other actuators were considered, the advantages, application limits and disad-vantages of each method were analyzed. Based on the results of the performed analytical procedure, as well as the recommendations known in the scientific and technical literature on improving the vibration-protective properties of suspension systems, the authors proposed and developed a new method for controlling the elastic-damping characteristic, which is implemented in the proposed technical solution for the air suspension of a vehicle seat. The method differs in the thing that it im-plements a cyclic controlled exchange of the working fluid between the cavities of the pneumatic elastic element and the additional volume of the receiver on the compression and rebound strokes, forming an almost symmetric elastic damping characteristic, and partial recuperation of vibrational energy by a pneumatic drive, presented in the form of a rotary type pneumatic motor. In addition, the method does not require an unregulated hydraulic shock absorber, while still having the ad-vantage of improved vibration-proof properties of the air suspension of a vehicle seat over a wide range of operating influences.

scholarly journals Design and Implementation of Single Stage PFC Microcontroller Based Drive For Permanent Magnet Brushless DC Motor

2013 ◽  
pp. 289-293
Author(s):  
Minal A Bodkhe ◽  
Vaishali Nandanwar
Keyword(s):  
Permanent Magnet ◽  
Power Factor ◽  
Dc Motor ◽  
Brushless Dc Motor ◽  
Brushless Dc ◽  
Three Phase ◽  
Wide Range ◽  
Sinusoidal Input ◽  
Bridge Rectifier ◽  
Permanent Magnet Brushless Dc

In this paper ,a new approach is presented aim at improving the power factor of three phase bridge inverter that equip with permanent Magnet Brushless DC motor(PMBLDCM)drive through microcontroller. Power factor correction converter is used for feeding a three phase bridge inverter based PMBLDC motor drive. The front end of PFC converter is a diode bridge rectifier fed from a step down transformer. In this three phase bridge inverter is operated as electronic commutator of the PMBLDCM .Nearly sinusoidal input current is achieved using. The proposed PMBLDCM drive with PFC converter is designed to run the motor to desired speed. This scheme improves an efficiency of proposed drive system with PFC feature in wide range of the speed and an input AC voltage.

Effect of Different Methods on Properties of SMA490BW Steel Welded Joints

2015 ◽  
Vol 1095 ◽  
pp. 902-905
Author(s):  
Xiang Yang Wu ◽  
Wei Chuang Qi ◽  
Yong Jun Liu ◽  
Yong Bin Han ◽  
Chun Hui Xia
Keyword(s):  
High Speed ◽  
High Strength ◽  
Automatic Welding ◽  
High Speed Train ◽  
Single Wire ◽  
Bogie Frame ◽  
Microstructure Observation ◽  
Wide Range ◽  
Design Requirements ◽  
Welding Productivity

Because of its advantages of high strength, good toughness and strong corrosion resistance capability, SMA490BW was access to a wide range of applications in bogie frame of high-speed train. Manual welding, single-wire automatic welding and double-wires automatic welding were used to weld plate butt joints of SMA490BW steel. The mechanical properties testing and microstructure observation were carried out. Results showed that the strength of welded joint and impact toughness could meet the design requirements with the above methods. Double-wires welding owned an outstanding advantages of saving energy and welding productivity in such the above methods which laid the foundation for application of double wires welding in bogie frame of high-speed train.

Stability Analysis of Finite Difference Model of Orthogonal Metal Cutting in Presence of Random Noises

1999 ◽  
Author(s):  
Alexandra Rodkina ◽  
Marian Wiercigroch
Keyword(s):  
Metal Cutting ◽  
Necessary Conditions ◽  
Random Noise ◽  
Resistance Force ◽  
Stable Operation ◽  
Difference Model ◽  
Single Degree Of Freedom ◽  
Wide Range ◽  
Orthogonal Metal Cutting ◽  
Cutting Processes

Abstract The dynamics of a nonlinear cutting process in the presence of random noise is defined and investigated. This approach is adequate for a wide range of models describing the orthogonal metal cutting processes by a single-degree-of-freedom oscillator, where the nonlinearity comes from the cutting force in form of a variable resistance force. The method of Lyapunov–Krasovskii functional was adopted to analyze the necessary conditions for a stable operation. The conditions ensuring an asymptotic stability in the presence of random noises are established.

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