Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Variable frequency drive schemes.
Artykuły w czasopismach na temat „Variable frequency drive schemes”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „Variable frequency drive schemes”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Alwadie, Abdullah. "A Concise Review of Control Techniques for Reliable and Efficient Control of Induction Motor". International Journal of Power Electronics and Drive Systems (IJPEDS) 9, nr 3 (1.09.2018): 1124. http://dx.doi.org/10.11591/ijpeds.v9.i3.pp1124-1139.
Pełny tekst źródłaStreszczenie:
<span style="color: black; font-family: 'Times New Roman','serif'; font-size: 10pt; mso-fareast-font-family: SimSun; mso-themecolor: text1; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;">Induction motors are work-horse of the industry and major element in energy conversion. The replacement of the existing non-adjustable speed drives with the modern variable frequency drives would save considerable amount of electricity. A proper control scheme for variable frequency drives can enhance the efficiency and performance of the drive. This paper attempt to provide a rigorous review of various control schemes for the induction motor control and provides critical analysis and guidelines for the future research work. A detailed study of sensor based control schemes and sensor-less control schemes has been investigated. The operation, advantages, and limitations of the various control schemes are highlighted and different types of optimization techniques have been suggested to overcome the limitations of control techniques</span>
2
Okedu, Kenneth E., i Akhtar Kalam. "Comparative Study of Grid Frequency Stability Using Flywheel-Based Variable-Speed Drive and Energy Capacitor System". Energies 16, nr 8 (18.04.2023): 3515. http://dx.doi.org/10.3390/en16083515.
Pełny tekst źródłaStreszczenie:
Recently, there has been a rise in the integration of renewable energy sources into power grids. As a result of this, there is a need to carry out new studies in order to understand the dynamics of power grids during disturbances that is mainly caused by the stochastic nature of wind energy. The operation of modern power grids that are tied to wind farms follows a stipulated grid requirement or grid codes, considering the allowable threshold frequency variation during grid dynamics. This paper presents a comparative study of two frequency control schemes considering grid frequency stability using two frequency control topologies. A novel dynamic flywheel scheme with a doubly fed induction generator (DFIG) variable-speed wind turbine with the coordinated control of excess kinetic energy and mechanical torque during operation was the first scheme, and a control strategy of an energy capacitor system (ECS) with a squirrel cage induction generator fixed-speed wind turbine (FSWT) was the second scheme. The salient part of this study was that the DFIG maximum point power tracking for effective smoothing of the output of the wind generator in the first scheme was designed based on the control strategy of its reference power to achieve smoothing of the wind power at the terminals of the wind generator. The model system employed in this work was a wind farm that is tied to a conventional power grid made of steam and hydro synchronous turbines. For an effective and fair comparison of results, the same natural wind speed was used in PSCAD/EMTDC for both schemes. When no control, Scheme 1, and Scheme 2 were implemented, the frequency dips were 47.20, 49.99, and 49.99 Hz with overshoots of 50.500, 50.005, and 50.001 Hz and recovery times of over 600.00, 0.01, 0.01 s, respectively, for the frequency variable.
3
Vasilyev, D. A., R. I. Gavrilov i L. A. Panteleeva. "Energy-efficient variable frequency asynchronous electric drive". Journal of Physics: Conference Series 2061, nr 1 (1.10.2021): 012053. http://dx.doi.org/10.1088/1742-6596/2061/1/012053.
Pełny tekst źródłaStreszczenie:
Abstract Currently, there are quite a large number of various scientific papers on the creation of a controlled asynchronous engine and the optimization of its modes, and the availability of acceptable results for practical implementation, but there is still no single generally accepted approach to solving the problem. In this regard, the issue of synthesis of scalar control systems that provide the minimum value of one or another criterion of energy efficiency is relevant. In this paper, we consider the obtained mathematical model of an asynchronous engine (AE), which differs from the known ones in that the parameters of the substitution scheme are expressed in terms of the stator and rotor conductivities. The energy characteristics of the AE in the sliding function are obtained, which make it possible to determine the dependences of the active and reactive components of the AE current and the possibility of their redistribution within the nominal value of the AE phase current. The principle of optimal frequency-current control of AE is formulated, which differs from the known ones in that, as an energy efficiency indicator, the value of the maximum energy efficiency of AE is used, expressed as the ratio of the active resistance of the rotor circuit to the total conductivity of the AE phase.
4
Yerbayev, Yerbol, Ivan Artyukhov, Artem Zemtsov, Denis Artyukhov, Svetlana Molot, Dinara Japarova i Viktor Zakharov. "Negative Impact Mitigation on the Power Supply System of a Fans Group with Frequency-Variable Drive". Energies 15, nr 23 (23.11.2022): 8858. http://dx.doi.org/10.3390/en15238858.
Pełny tekst źródłaStreszczenie:
The technological installations’ characteristics are possible to improve by equipping fans with a frequency-controlled electric drive. However, it can lead to an electromagnetic compatibility problem in the electrical supply system. This problem becomes worse if a large number of fans are included in the technological installation and the electric drives are powered from a substation connected to a limited power source. As an example, in this article we investigate the power supply system of a gas cooling unit with variable-frequency electric drives for fans. The electric drives’ operating mode dependences characterizing the non-sinusoidal voltages and currents of the power source are obtained with the help of simulation modeling in the MATLAB environment with the Simulink expansion package. The typical substation circuit usage for the power supply of a group of fans with a frequency-controlled drive does not meet the requirements of IEEE Standard 519-2014. We can solve the problem of electromagnetic compatibility by changing the substation topology and organizing DC busbars and replacing frequency converters with inverters. We proposed forming DC busbars using 12-pulse rectifiers powered by transformers with two secondary windings with different connection schemes. The simulation results confirmed that the proposed substation topology provides the voltage and current harmonics level on the substation power busbars in accordance with the IEEE Standard 519-2014 requirements over the entire frequency range of the fans’ motor control.
5
Han, Qiguo, Kai Zhu, Wenming Shi, Kuayu Wu i Kai Chen. "Research on the supercapacitor support schemes for LVRT of variable-frequency drive in the thermal power plant". IOP Conference Series: Earth and Environmental Science 121 (luty 2018): 042021. http://dx.doi.org/10.1088/1755-1315/121/4/042021.
Pełny tekst źródła
6
Rekha, Mudundi, i Malligunta Kiran Kumar. "Variable frequency drive optimization using torque ripple control and self-Tuning PI controller with PSO". International Journal of Electrical and Computer Engineering (IJECE) 9, nr 2 (1.04.2019): 802. http://dx.doi.org/10.11591/ijece.v9i2.pp802-814.
Pełny tekst źródłaStreszczenie:
Drive’s output power must be restricted for the prevention of stresses over higher components in the input power system while utilizing a three-phase Variable Frequency Drive (VFD) which has powered from a single-phase AC source. To resolve this problem, we introduced a novel motor q-axis current (M-QAC) with torque ripple control (TRC) of an induction motor and self-tuning PI controller with particle swarm optimization (STP-PSO) for mitigating the stress over induction motor by the torque ripple elimination and controlling. Our proposed approach has an information related to the different parts stresses of the VFD which includes the terminal block and the diodes in the input side, DC bus capacitors, torque ripple, harmonics in the current and active performance for sudden changes in the speed and load. Our proposed model is simulated in MATLAB/Simulink environment. In this paper the standard dc-bus voltage ripple-based fold- back, q-axis average current fold-back and q-axis ripple current fold-back methods are utilized for the comparative analysis. Also the comparative analysis of proposed M-QAC, TRC and STP-PSO methodologies are provide with respect to steady-state values of peak-to-peak dc voltage (Vdc), peak-to-peak input current (IINPUT), input RMS current (IRMS), motor speed and the output power. Extensive simulated performance show that the STP-PSO obtained superior results over conventional standard dc-bus voltage ripple-based fold-back method, M-QAC and TRC schemes.
7
Hruntovich, N. V., A. A. Kapanski, D. Baczynski, G. V. Vagapov i O. V. Fedorov. "Optimization of a variable frequency drive pump working on a water tower". E3S Web of Conferences 124 (2019): 05060. http://dx.doi.org/10.1051/e3sconf/201912405060.
Pełny tekst źródłaStreszczenie:
The development of the existing water supply system in towns and villages involves the use of frequency converters and specialized control algorithms that can maintain the pressure level established in the supply grid within certain limits. The implementation of the standard scheme includes the elimination of the water tower, which, on the one hand, reduces the cost of its maintenance. On the other hand, in emergency situations, the water tower can still supply water to the consumer, which increases the time of uninterrupted water supply during repairs. The article reveals a method of increasing the energy efficiency of transporting drinking water with the help of a water tower by eliminating the excessive pressure of the water rise when using frequency converters. Our research that involved more than 300 pumping stations, allowed to establish the average value of the excessive pressure of water rise, which reached 0.36 MPa. For the wells under study, optimization of the pump operation modes revealed the energy-saving potential of up to 52% due to excessive pressure reduction and up to 2.0% due to a decrease in starting power at the time of engine acceleration.
8
Choi, Yoon-Geol, Hyeon-Seok Lee, Bongkoo Kang, Su-Chang Lee i Sang-Jin Yoon. "Compact Single-Stage Micro-Inverter with Advanced Control Schemes for Photovoltaic Systems". Energies 12, nr 7 (31.03.2019): 1234. http://dx.doi.org/10.3390/en12071234.
Pełny tekst źródłaStreszczenie:
This paper proposes a grid-connected single-stage micro-inverter with low cost, small size, and high efficiency to drive a 320 W class photovoltaic panel. This micro-inverter has a new and advanced topology that consists of an interleaved boost converter, a full-bridge converter, and a voltage doubler. Variable switching frequency and advanced burst control schemes were devised and implemented. A 320 W prototype micro-inverter was very compact and slim with 60-mm width, 310-mm length, and 30-mm height. In evaluations, the proposed micro-inverter achieved CEC weighted efficiency of 95.55%, MPPT efficiency >95% over the entire load range, and THD 2.65% at the rated power. The proposed micro-inverter is well suited for photovoltaic micro-inverter applications that require low cost, small size, high efficiency, and low noise.
9
Lipinskis, Tadas, i Vytautas Bleizgys. "EXPERIMENTAL INVESTIGATION OF A SIX-PHASE VARIABLE FREQUENCY DRIVE / ŠEŠIŲ FAZIŲ DAŽNINĖS PAVAROS EKSPERIMENTINIS TYRIMAS". Mokslas – Lietuvos ateitis 8, nr 3 (29.06.2016): 339–44. http://dx.doi.org/10.3846/mla.2016.937.
Pełny tekst źródłaStreszczenie:
Experimental results of a variable frequency drive, consisting of a six-phase voltage source inverter and six-phase asynchronous AC motor are presented in this paper. Frequency converter uses a six-phase space vector PWM scheme created by the author. The voltage forming scheme is implemented in Matlab/Simulink, and logical signals for inverter control are transferred from PC via the National instruments PCI-6024E data acquisition card. Voltages, at which the experimental motor operates at maximum efficiency, were determined experimentally. Motor transitions, when it is operating with one, two, and three failed phase windings are presented, confirming that a six-phase motor can operate with up to three failed windings. Darbe pateikiami dažninės pavaros, sudarytos iš šešių fazių dažnio keitiklio ir šešių fazių asinchroninio elektros variklio, eksperimentinių tyrimų rezultatai. Šešių fazių įtampai formuoti taikomas autoriaus sukurtas erdvinių vektorių moduliacijos algoritmas, naudojantis vidutinio ilgio vektorius. Algoritmas realizuotas asmeniniu kompiuteriu Matlab/Simulink terpėje. Signalams inverterio raktų valdymui iš kompiuterio gauti panaudotas National Instruments PCI-6024E duomenų įvesties/ išvesties įrenginys. Atlikti inverterio įtampos, kuriai esant šešių fazių variklis dirba maksimaliu naudingumo koeficientu, tyrimai. Pateikiami šešių fazių variklio greičio ir sukimo momento pereinamųjų procesų tyrimo rezultatai, esant vienos, dviejų ir trijų variklio apvijų gedimams, patvirtinantys, kad šešių fazių variklis gali ribotai veikti sugedus iki trijų apvijų.
10
Soni, Umesh Kumar, i Ramesh Kumar Tripathi. "High Load Fast Startup Sensorless Control of Wheel BLDC Motor with Line-to-Line Back EMF Extraction Using Least Pth-Norm IIR Digital Filter". Journal of Circuits, Systems and Computers 29, nr 09 (19.11.2019): 2050145. http://dx.doi.org/10.1142/s0218126620501455.
Pełny tekst źródłaStreszczenie:
In this paper, an effective scheme of on-load startup with reduced current has been proposed for BLDC motor and the steady as well as dynamic performance in all four quadrants was verified. Hysteresis band-limited back EMF noise provides the starting pulses, the frequency of which depends on the threshold factor in speed proportional threshold. Scheme is quite fast, comparatively to the state-of-the art schemes of startup and less complex than time-consuming initial position detection (IPD) algorithm. Second-order least [Formula: see text]th-norm infinite impulse response (IIR) digital low pass filter realized in MATLAB/Simulink has been used for extraction of line-to line back EMF from line-to-line terminal voltages measured with two voltage sensors. Proposed filter has wide flexibility of online variation of cut-off frequency, gain and phase without any circuit-based modification due to variability of filter coefficients. This enables the smooth filtering with minimized phase delay in low speed range irrespective of any duty cycle and PWM frequency. Linear compensation of phase error or phase advancement for desired current profile can easily be achieved by the varying the threshold factor. In this experiment, the threshold factor of 1/1460 has been found most suitable for smooth sensorless startup without jerk, vibration and reverse rotation, as the motor operates in advanced mode with this value. First, the performance of Hall sensor-based drive was studied using open loop variable duty cycle speed control. The controller was designed in MATLAB/Simulink platform and implemented using TMS320F28069M DSP control stick with Code composer Studio V5. Later on, a complete controller for proposed sensorless scheme was developed in MATLAB/Simulink environment and was implemented using NI-PCI6221 Controller installed in PC. The proposed sensorless drive has been found capable of operating at very low speed of 50[Formula: see text]rpm in voltage control mode and 85[Formula: see text]rpm in current chopping PWM mode. Approximately 85[Formula: see text]ms less time was taken by sensorless drive to reach the same speed when compared with Hall-based control for identical loading. Also less overshoots during startup was observed. Overlap time of 0.05[Formula: see text]ms between phase currents has been achieved during commutation period.
11
Sohaib Choudhary, Muhammad, Muhammad Saqlain Saqi, Muhammad Rameez Javed, Hasan Erteza Gelani, Muhammad Akram, Muhammad Kashif Amjad i Sana Khan. "Solar powered space vector pulse width modulation based induction motor drive for industry applications". Bulletin of Electrical Engineering and Informatics 11, nr 4 (1.08.2022): 1828–36. http://dx.doi.org/10.11591/eei.v11i4.3023.
Pełny tekst źródłaStreszczenie:
The new millennium has witnessed a rapid growth in the development of solar-powered electric systems as well as variable frequency drives (VFDs). Predominantly, pulse width modulation (PWM) based adjustable frequency drives are being employed in the industry for providing superior performance. The space vector pulse width modulation (SVPWM) has gained importance due to its improved harmonic profile. In the current effort, SVPWM based VFD for an induction motor is devised equipped with a push-pull converter for optimal performance. A feedback system is incorporated for motor controls. The SVPWM is implemented using FPGA based my-RIO controller because of its effective processing and power handling capabilities; whereas the feedback control is furnished using Lab-View. The performance of the proposed scheme is analyzed. The results confirm flexible control of the motor incorporated with the presented drive system which is supplied via solar power.
12
Mushtaq, Basit, i Mairaj-Ud-Din Mufti. "Stability Enhancement of Electric Power Systems by Employing Variable Frequency Transformer". IOP Conference Series: Materials Science and Engineering 1228, nr 1 (1.03.2022): 012013. http://dx.doi.org/10.1088/1757-899x/1228/1/012013.
Pełny tekst źródłaStreszczenie:
Abstract Economical and technical advantages inherent in the coordinated operation of power systems resulted in large-scale grid interconnection. The major concern regarding the interconnection of the neighbouring power systems with relatively weak tie-lines is the appearance of poorly damped electromechanical oscillations. Inter-area (IA) oscillations reduce system stability and transmission capacity, and without an efficient damping mechanism, these oscillations can cause system failure and even lead to large-scale blackouts. In this work, the impact of variable frequency transformer (VFT) on the IA oscillations of a two-area power system connected in series with the tie-line is investigated. The VFT is a recent power transmission technology that offers continuous control over bi-directional power flow with no harmonic injection. The VFT is made up of a rotary transformer for continuously regulated phase shift, as well as a drive system and control that regulates the power flow through the VFT by adjusting the angle and speed of the rotary transformer. The VFT is controlled to increase system damping, and consequently suppress inter-area oscillations. A comprehensive model of the interconnected power system including VFT is developed in the MATLAB/Simulink environment to study the efficacy of the proposed scheme.
13
Echeikh, Hamdi, Hichem Kesraoui, Ramzi Trabelsi, Atif Iqbal i Mohamed Faouzi Mimouni. "A novel DTC scheme for a sensorless five-phase IM drive under open-phase fault". COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, nr 2 (4.03.2019): 829–44. http://dx.doi.org/10.1108/compel-01-2018-0036.
Pełny tekst źródłaStreszczenie:
Purpose This paper aims to deal with direct torque controller when the five-phase induction motor drive in faulty operation. Precisely, open-phase fault condition is contemplated. Also, the DTC is combined with a speed-adaptive variable-structure observer based on sliding mode observer. Design methodology/approach Two novel features are presented. First, the concept of the virtual voltage vector is presented, which eliminates low-frequency harmonic currents and simplifies analysis. Second, speed information is introduced into the selection of the inverter states. Findings Direct torque control (DTC) is largely used in traditional three-phase drives as a backup to rotor-stator flux-oriented methods. The classic DTC strategy was primarily designed on the base of hysteresis controllers to control two independent variables (speed, torque and flux). Due to the additional degrees of freedom offered by multiphase machine, extensive works have been extended on the ensemble five-phase drives in healthy operation. In addition, the ability to continue the operation in faulty conditions is considering one of the main advantages of multiphase machines. One can find in the literature different approaches treating this subject. The applicability of DTC after the appearing of a fault has not been enclosed in the literature. Originality/value Theoretical development is presented in details followed by simulation results using Matlab/Simulink to analyze the performance of the drive, comparing with the behavior during healthy situation.
14
Jaafar, Miriam, David Martínez-Martín, Mariano Cuenca, John Melcher, Arvind Raman i Julio Gómez-Herrero. "Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids". Beilstein Journal of Nanotechnology 3 (18.04.2012): 336–44. http://dx.doi.org/10.3762/bjnano.3.38.
Pełny tekst źródłaStreszczenie:
We introduce drive-amplitude-modulation atomic force microscopy as a dynamic mode with outstanding performance in all environments from vacuum to liquids. As with frequency modulation, the new mode follows a feedback scheme with two nested loops: The first keeps the cantilever oscillation amplitude constant by regulating the driving force, and the second uses the driving force as the feedback variable for topography. Additionally, a phase-locked loop can be used as a parallel feedback allowing separation of the conservative and nonconservative interactions. We describe the basis of this mode and present some examples of its performance in three different environments. Drive-amplutide modulation is a very stable, intuitive and easy to use mode that is free of the feedback instability associated with the noncontact-to-contact transition that occurs in the frequency-modulation mode.
15
Khvatov, Oleg Stanislavovich, Timur Zakariyaevich Bilyaletdinov, Pavel Vadimovich Kuznetsov i Dmitriy Konstantinovich Markov. "Assessment of reliability of variable speed diesel asynchronous generator sets". Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2023, nr 3 (31.08.2023): 88–96. http://dx.doi.org/10.24143/2073-1574-2023-3-88-96.
Pełny tekst źródłaStreszczenie:
Calculation and subsequent analysis of reliability indicators is a mandatory stage of development and commissioning of technical devices. There has been carried out an assessment of reliability in relation to diesel generator sets operating in the mode of adjustable rotational speed at shared loads, which ensures their high energy efficiency. Unconditional compliance with the requirements for the quality of the generated energy (amplitude and frequency of the voltage in the ship's network) is realized in these generating devices by means of semiconductor converter technology. It is obvious that the increased technical complexity of variable-speed generator sets, which can be attributed to the class of machine-valve generator complexes, is associated with a certain decrease in their reliability indicators. There are presented structural schemes and indicated the composition of power equipment and controls for machine-valve generator complexes based on asynchronous generators with a short-circuited and phase rotor. The method of calculating the reliability indicators of these asynchronous diesel generator complexes is considered. The results of calculating the failure rate and operating time for failure are given, taking into account the load diagram of the power plant and the tachogram of the drive internal combustion engine, which corresponds to operation at energy-efficient rotational speeds at optimal (close to nominal) specific fuel consumption. The results of a comparative analysis of the operating time for failure allow us to determine the most reliable version of asynchronous generator electrical installation in operation.
16
He, Yunfeng, You-Sheng Wang, Qinfen Lu, Lei Zhang i Fang Liang. "Design of single-sided linear induction motor for low-speed Maglev vehicle in 160 km/h and variable slip frequency control". Transportation Systems and Technology 4, nr 2 (13.09.2018): 120–28. http://dx.doi.org/10.17816/transsyst201842120-128.
Pełny tekst źródłaStreszczenie:
Background: The mid-low speed Maglev train adopts the single-sided linear induction motors (SLIMs) as drive part, of which design and control method has become research hotspot when the velocity is elevated from 120 km/h to 160 km/h.
Aim: For SLIMs applied in 160 km/h low-speed maglev train, the design scheme is introduced and then a novel variable slip frequency control method is proposed.
Methods of the studies: This control method adopts low slip frequency at start-up to produce large starting traction force and high slip frequency during high velocity area to obtain great power. The influence to the normal force is also investigated.
Results: With this method, the weight of the system can be effectively reduced and the lightweight design of SLIM is realized.
Conclusion: The novel variable slip frequency control method meets the requirement of both high starting acceleration and enough residual acceleration for 160 km/h mid-low speed maglev train.
17
Xiao, Fei, Lei Yuan i Ming Liang Chen. "Adaptive Sliding-Mode Observer Scheme for Sensorless Control of Low-Speed IPMSM Drive". Applied Mechanics and Materials 380-384 (sierpień 2013): 536–40. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.536.
Pełny tekst źródłaStreszczenie:
This paper proposes an adaptive sliding-mode observer (SMO) for a low-speed interior permanent magnet synchronous motor (IPMSM) drive. In this paper, an adaptive SMO is employed to estimate the rotor speed and extended EMF, a soft phase locked loop (PLL) technology is used to estimate rotor position due to its strong robustness since under voltage phase unbalance or polluted and variable-frequency environment. The global asymptotic stability of the proposed adaptive SMO is verified using Lyapunov stability analysis with considering motor parameter variations. Simulation results are presented to verify the principles and to demonstrate the effectiveness of the proposed method.
18
Nizimov, Victor, i David Chugunov. "MATHEMATICAL MODEL OF VARIABLE PRODUCTIVITY PROCESS PUMP UNIT OF THE WATER SUPPLY SYSTEM". Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences) 1, nr (42) (22.05.2023): 86–92. http://dx.doi.org/10.31319/2519-2884.42.2023.10.
Pełny tekst źródłaStreszczenie:
The paper solves an actual scientific problem, which consists in the development of a mathematical model of the pumping unit in the variable performance mode. Built compatible characteristics-contacts of the pump unit and the network according to the load schedule when adjusting the performance by the valve and the speed of rotation of the impeller. The functional scheme of the electric drive according to the CF-AM system is given. The purpose of the study is to develop a mathematical model of a pump unit in variable performance modes with a frequency-controlled electric drive of alternating current to ensure the necessary parameters (pressure, performance) and reliable water supply to consumers in general. The structural diagram of the linearized model of the pumping unit was developed. A comparative evaluation of the simulation results was performed when adjusting the variable productivity by the valve and the speed of the impeller. From the above results of mathematical modelling, it was determined that the application of the developed model allows the regulation of productivity as a function of time using a latch or the speed of rotation of the impeller.
19
Rodríguez-Olivares, Noé, José Cruz-Cruz, Alejandro Gómez-Hernández, Rodrigo Hernández-Alvarado, Luciano Nava-Balanzar, Tomás Salgado-Jiménez i Jorge Soto-Cajiga. "Improvement of Ultrasonic Pulse Generator for Automatic Pipeline Inspection". Sensors 18, nr 9 (5.09.2018): 2950. http://dx.doi.org/10.3390/s18092950.
Pełny tekst źródłaStreszczenie:
This paper presents the improvement of an ultrasonic pulse generator for a pipeline inspection gauge (PIG), which uses 64 transducers for inspecting distances up to 100 km with an axial resolution fixed at 3 mm and variable speeds between 0 and 2 m/s. An ultrasonic pulse generator is composed of a high-voltage (HV) MOSFETs, driver logic and an HV power supply. We used a DC-HV DC converter device as the HV power supply because it reduces the size of the ultrasound system considerably. However, pipeline geometry and inspection effects such as hammer and shock cause a variable pulse repetition frequency (PRF), producing voltage drops, poor quality of the HV pulse generated, failures in the dimensioning of defects and damage to devices by over-voltage. Our improvement is to implement a control scheme to maintain the high quality of the HV regardless of the variable PRF. To achieve this, we characterized three transfer functions of the DC-HV DC converter, varying the connected load to 10%, 45% and 80%. For the characterization, we used the least squares technique, considering an autoregressive exogenous (ARX) model. Later, we compared three control schemes: (1) proportional-integral-derivative (PID) tuned by simultaneous optimization of several responses (SOSR), (2) PID tuned by a neural network (NN) and (3) PI tuned by the analytical design method (ADM). The metrics used to compare the control schemes were the recovery time, the maximum over-voltage and the excess energy when the shock and hammer effects happen to occur. Finally, to verify the improvement of the HV pulser, we compared the ultrasonic pulses generated for various frequencies and amplitudes using the pulse generator with and without the control scheme.
20
Ashraf, Naveed, Ghulam Abbas, Nasim Ullah, Ahmad Aziz Al-Ahmadi, Abdul Rehman Yasin, Ahmed Bilal Awan i Mohsin Jamil. "A Transformerless AC-AC Converter with Improved Power Quality Employed to Step-Down Power Frequency at Output". Energies 15, nr 2 (17.01.2022): 667. http://dx.doi.org/10.3390/en15020667.
Pełny tekst źródłaStreszczenie:
Variable voltage and frequency are required to govern the torque-speed characteristics of many industrial drive systems. Traditionally, this is achieved with a power converting system implemented with multistage converters. This technology is based on rectifying AC power into DC and then DC into AC with an inverter circuit. The power quality concerns of both conversion stages are tackled by selecting high switching frequency PWM control and harmonics mitigation filters. Also, using a bulky DC-link capacitor is one of the big sources of low system reliability, so this approach increases the conversion losses, circuit, and control complications. The frequency step-down conversion is very attractive with direct AC-AC converters as it has a simple control and circuit structure, but these converters face poor power quality challenges once the output frequency is decreased with respect to an input. In these converters, the total harmonic distortion (THD) of the output voltage becomes very poor once the output frequency is reduced. The problem of high THD of the output is addressed in the power converting circuits implemented with line frequency multi-winding transformers. The required number of output winding and switching devices (diodes and thyristors) increases once the value of the output frequency is decreased. This will increase the overall volume, cost, and losses. The use of a bulky and costly line frequency transformer may be eliminated if AC voltage controllers have non-inverted and inverted voltage buck capabilities, such existing topologies either have complex control schemes or require a large number of operating devices. Therefore, in this research article, a new transformerless frequency step-down converter employing fewer devices is proposed. This approach is realized with a high-frequency controlled rectifier for the required voltage stabilization and a low-frequency inverter bridge for frequency control. Its validation is supported by the results attained from Simulink and practical-based prototypes.
21
Shamseldin, Mohamed A., Abdel Halim M. Bassiuny i Abdel Ghany M. Abdel Ghany. "Design variable structure fuzzy control based on deep neural network model for servomechanism drive system". International Journal of Power Electronics and Drive Systems (IJPEDS) 13, nr 4 (1.12.2022): 2529. http://dx.doi.org/10.11591/ijpeds.v13.i4.pp2529-2540.
Pełny tekst źródłaStreszczenie:
This paper presents a new scheme for variable structure (VS) fuzzy PD controller. The rule base of the fuzzy PD controller is tuned online. The purpose of the proposed controller is to track accurately a preselected position command for the servomechanism system. Therefore, this study establishes a model using a black-box modeling approach; simulations were performed based on real-time data collected by LabVIEW and processed using MATLAB. The input signal for the servomechanism driver is a pseudo-random binary sequence that considers violent excitation in the frequency interval. The candidate models were obtained using linear least squares, nonlinear least squares, and deep neural network (DNN). The validation results proved that the identified model based on DNN has the smallest mean square errors. Then, the DNN identified model was used to design the proposed control techniques. A comparison had been executed between the VS fuzzy PD control, the conventional PD control, and the fixed structure fuzzy PD control. The experimental results confirm the proposed VS fuzzy PD control can absorb the nonlinear behavior of the system. The speed regulation test, it reduces the rise time from 50% to 56%. While continuously changing in speed, it has the smallest tracking error (0.412 inches).
22
Sankar, A. Bharathi, i R. Seyezhai. "Investigation of PMSG Fed Diode-Clamped Multilevel Inverter for Wind Energy System". Advanced Materials Research 768 (wrzesień 2013): 16–22. http://dx.doi.org/10.4028/www.scientific.net/amr.768.16.
Pełny tekst źródłaStreszczenie:
Wind energy has drawn worldwide attention because of its simple structure, high efficiency and stable operation. Recently, variable speed constant frequency (VSCF) direct-drive wind power generation system using permanent magnet synchronous generator (PMSG) has gained popularity. This paper focuses on the simulation of PMSG fed diode clamped MultiLevel Inverter (MLI) for wind applications. A three-level MLI with phase disposition PWM technique has been proposed. Simulation studies on the proposed scheme have been carried out in MATLAB and spectral quality of the output has been investigated.
23
Magzoub, Muawia A., Nordin B. Saad i Rosdiazli B. Ibrahim. "The Impacts of the Disturbances for the Hybrid Fuzzy-Fuzzy Controller Applied to Induction Motor Drive". Applied Mechanics and Materials 785 (sierpień 2015): 116–21. http://dx.doi.org/10.4028/www.scientific.net/amm.785.116.
Pełny tekst źródłaStreszczenie:
The study of the effects of an internally and externally caused disturbances for the advanced hybrid fuzzy-fuzzy controller (HFFC) scheme in order to gain control over the speed of an induction motor’s (IM) variable speed drive (VSD) is the main objective of this research paper The HFFC works on the principle of gaining control over the rotor speed during steady-state stage using fuzzy stator current magnitude controller whereas, during an accelerate-decelerate stage by utilising a fuzzy frequency controller, to overcome the disadvantage of field oriented control (FOC) method. The design of a scalar controller involves two aspects of FOC i.e current and frequency. Hence, the performance of a controller has been observed with a series of tests which yielded a controller which is more effective, consistent and insensitive to the parameter variation for the motor and system strength to noise and load disturbances.
24
Zheng, Bin, Shengyan Fu i Jilin Lei. "Topology Optimization and Multiobjective Optimization for Drive Axle Housing of a Rear Axle Drive Truck". Materials 15, nr 15 (30.07.2022): 5268. http://dx.doi.org/10.3390/ma15155268.
Pełny tekst źródłaStreszczenie:
As one of the important load-bearing components of a truck, the drive axle housing must meet the requirements of stiffness and strength. The traditional design method uses redundancy design to meet the performance requirements. The joint design between the three-dimensional mathematical model and finite element model is adopted, and the optimal design of the drive axle housing is realized based on topology optimization and multiobjective optimization. Firstly, the static analysis of the drive axle housing of a rear axle drive truck was carried out with four typical working conditions. It was concluded that the four working conditions all operate under the yield limit of the material, and it was found that the maximum equivalent stress of the four working conditions occurs at the step of the half-shaft casing. Among the four working conditions, the most critical one is the maximum vertical force working condition. Then, based on the maximum vertical force working condition, the fatigue life analysis is conducted, and the minimum fatigue life appears at the transition position of the half-shaft sleeve and the arc transition position of the main reducer chamber. The remaining parts can meet the design requirements. The overall safety factor of the drive axle housing is mainly between 1 and 5 when operating under this working condition. Then, through modal analysis, the first to sixth natural frequency and vibration modes of the drive axle housing are extracted. Based on the modal analysis, the dynamic characteristics of the drive axle housing are further studied by harmonic response analysis and random vibration analysis. Finally, two kinds of lightweight optimization schemes for the drive axle housing are given. Topology optimization reduces the mass of the drive axle housing by 17.4%, but the overall performance slightly decreases. Then, the five dimensional parameters of the drive axle housing are selected as design variables. The mass, maximum deformation, equivalent stress, service life, and the first-, second- and third-order natural frequencies are defined as objective functions. Through the optimal space-filling design method, the experimental designs are performed and the sample points are obtained. Based on the results of experiment design, the multiobjective genetic algorithm and response surface method are combined to optimize the objective functions. The analysis results show that the mass is reduced by 4.35%, the equivalent stress is reduced by 21.05%, the minimum life is increased by 72.28%, and the first-, second-, and third-order natural frequency are also increased to varying degrees. Two different optimization strategies are provided for the design of the drive axle housing.
25
Shprekher, Dmitry, Gennady Babokin i Dmitry Ovsyannikov. "The Control System for Leveling Loads in a Drag Conveyor Multi-Motor Drive". Известия высших учебных заведений. Электромеханика 65, nr 3 (2022): 56–65. http://dx.doi.org/10.17213/0136-3360-2022-3-56-65.
Pełny tekst źródłaStreszczenie:
Drag conveyor is the main means of delivering coal from the cutter loader to the vehicles of the belt entry in under-ground mining of coal deposits. In powerful drag conveyors, in conditions of limited equipment in terms of dimensions, a multi-motor electric drive is used, including from two to four electric motors. The load imbalance between the motors in such an electric drive is its main problem. In order to solve this problem, the existing methods of load balancing in a multi-motor electric drive have been analyzed and a strategy for a variable frequency drive with vector control of sev-eral motors based on the "master-slave" principle has been proposed. In this case, the main motor is controlled by the speed controller, and the slave motor is controlled using the torque command strategy. This control scheme has been implemented in the MATLAB/Simulink environment. The simulation results showed that the master-slave control mode can solve the problem of the load leveling of the drag conveyor in all modes of its operation, thereby increasing the life of the drag conveyor, reducing equipment wear, and thus increasing the efficiency of mine production.
26
Shargorodskiy, Serhiy, Vasyliy Yanishevskiy i Olga Yalina. "OVERVIEW OF TECHNOLOGIES AND TECHNOLOGICAL EQUIPMENT FOR HAYME PROCESSING". ENGINEERING, ENERGY, TRANSPORT AIC, nr 3(110) (30.10.2020): 145–52. http://dx.doi.org/10.37128/2520-6168-2020-3-15.
Pełny tekst źródłaStreszczenie:
Fodder production is one of the most important sectors of the agro-industrial complex of Ukraine, the pace and scientific and technical level of development of which largely determines the solution of the country's food problem, full satisfaction of the population's food needs. A limiting factor for the development of this industry is the lack of efficient, easy-to-use and cheap equipment for collecting, raking, stirring, and pressing domestically produced hay, which would be able to compete with foreign analogues. The publication is devoted to the development of a hydraulic drive of the working bodies of the rake of a thief. The analysis of the designs of the existing machines for raking hay into rolls is carried out. A characteristic feature of these machines is the presence of specialized working bodies and the need to ensure a given frequency of their rotation. The proposed hydraulic scheme for the drive of the working bodies. The hydraulic drive consists of a variable displacement pumping station, a hydraulic flow divider and two hydraulic motors. The use of this drive allows to simplify the layout of the machine and provide an efficient drive in compliance with all process requirements. In addition, the use of a hydraulic drive allows you to increase the number of working bodies, thereby increasing the width of the rake - hackers. The introduction of these changes in the design of this unit will allow to reduce the number of passes of the rake-hacker and pick-up press across the field, thereby ensuring fuel economy. As the review of literary sources shows, the issues of collecting and storing hay are relevant not only for our country, but also for other European countries. The designs of domestic rakes - hackers are morally obsolete, do not meet modern agrotechnical requirements, have a small working width and require frequent repair and maintenance. Based on the results of the analysis of the designs of the drives of the working bodies of the rake - hackers, a hydraulic scheme for the drive of the working bodies was proposed. A feature of this hydraulic drive is the presence of a throttle flow distributor with the possibility of smooth flow control.
27
Sahu, M. K., A. K. Panda i B. P. Panigrahi. "Direct Torque Control for Three-Level Neutral Point Clamped Inverter-Fed Induction Motor Drive". Engineering, Technology & Applied Science Research 2, nr 2 (11.04.2012): 201–8. http://dx.doi.org/10.48084/etasr.117.
Pełny tekst źródłaStreszczenie:
Direct torque control (DTC) is a control technique in AC drive systems to obtain high performance torque control. The classical DTC drive contains a pair of hysteresis comparators and suffers from variable switching frequency and high torque ripple. These problems can be solved by using space vector depending on the reference torque and flux. In this paper the space vector modulation technique is applied to the three-level Neutral Point Clamped (NPC) inverter control in the proposed DTC-based induction motor drive system, resulting to a significant reduce of torque ripple. Three-level neutral point clamped inverters have been widely used in medium voltage applications. This type of inverters have several advantages over standard two-level VSI, such as greater number of levels in the output voltage waveforms, less harmonic distortion in voltage and current waveforms and lower switching frequencies. This paper emphasizes the derivation of switching states using the Space Vector Pulse Width Modulation (SVPWM) technique. The control scheme is implemented using Matlab/Simulink. Experimental results using dSPACE validate the steady-state and the dynamic performance of the proposed control strategy.
28
Nikitin, Yury, Pavol Božek i Jozef Peterka. "Logical–Linguistic Model of Diagnostics of Electric Drives with Sensors Support". Sensors 20, nr 16 (8.08.2020): 4429. http://dx.doi.org/10.3390/s20164429.
Pełny tekst źródłaStreszczenie:
The presented paper scientifically discusses the progressive diagnostics of electrical drives in robots with sensor support. The AI (artificial intelligence) model proposed by the authors contains the technical conditions of fuzzy inference rule descriptions for the identification of a robot drive’s technical condition and a source for the description of linguistic variables. The parameter of drive diagnostics for a robotized workplace that is proposed here is original and composed of the sum of vibration acceleration amplitudes ranging from a frequency of 6.3 Hz to 1250 Hz of a one-third-octave filter. Models of systems for the diagnostics of mechatronic objects in the robotized workplace are developed based on examples of CNC (Computer Numerical Control) machine diagnostics and mechatronic modules based on the fuzzy inference system, concluding with a solved example of the multi-criteria optimization of diagnostic systems. Algorithms for CNC machine diagnostics are implemented and intended only for research into precisely determined procedures for monitoring the lifetime of the mentioned mechatronic systems. Sensors for measuring the diagnostic parameters of CNC machines according to precisely determined measuring chains, together with schemes of hardware diagnostics for mechatronic systems are proposed.
29
Xu, Chenhan, Huining Li, Zhengxiong Li, Hanbin Zhang, Aditya Singh Rathore, Xingyu Chen, Kun Wang, Ming-chun Huang i Wenyao Xu. "CardiacWave". Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 5, nr 3 (9.09.2021): 1–26. http://dx.doi.org/10.1145/3478127.
Pełny tekst źródłaStreszczenie:
Using wireless signals to monitor human vital signs, especially heartbeat information, has been intensively studied in the past decade. This non-contact sensing modality can drive various applications from cardiac health, sleep, and emotion management. Under the circumstance of the COVID-19 pandemic, non-contact heart monitoring receives increasingly market demands. However, existing wireless heart monitoring schemes can only detect limited heart activities, such as heart rate, fiducial points, and Seismocardiography (SCG)-like information. In this paper, we present CardiacWave to enable a non-contact high-definition heart monitoring. CardiacWave can provide a full spectrum of Electrocardiogram (ECG)-like heart activities, including the details of P-wave, T-wave, and QRS complex. Specifically, CardiacWave is built upon the Cardiac-mmWave scattering effect (CaSE), which is a variable frequency response of the cardiac electromagnetic field under the mmWave interrogation. The CardiacWave design consists of a noise-resistant sensing scheme to interrogate CaSE and a cardiac activity profiling module for extracting cardiac electrical activities from the interrogation response. Our experiments show that the CardiacWave-induced ECG measures have a high positive correlation with the heart activity ground truth (i.e., measurements from a medical-grade instrument). The timing difference of P-waves, T-waves, and QRS complex is 0.67%, 0.71%, and 0.49%, respectively, and a mean cardiac event difference is within a delay of 5.3 milliseconds. These results indicate that CaridacWave offers high-fidelity and integral heart clinical characteristics. Furthermore, we evaluate the CardiacWave system with participants under various conditions, including heart and breath rates, ages, and heart habits (e.g., tobacco use).
30
Oleschuk, V. I. "Synchronous Multi-Zone Modulation for Control of Inverter-Based Power Electronic Systems: Overview of Recent Research". Elektronnaya Obrabotka Materialov 58, nr 5 (październik 2022): 51–70. http://dx.doi.org/10.52577/eom.2022.58.5.51.
Pełny tekst źródłaStreszczenie:
This publication provides a brief overview of the results of recent research works by the author in the field of power electronics, carried out and published mainly in 2019–2021, and awarded with the Premium “Boris Lazarenko” of the Academy of Sciences of Moldova in the field of engineering. The methodological basis of those investigations is an original alternative method of the synchronous multi-zone space-vector modulation of signals of voltage source inverters as the main workhorses of adjustable speed electric drives and renewable energy systems. Therefore, basic strategies, schemes, and algorithms of synchronous multi-zone modulation have been further developed, modernized, modified, and disseminated for the control of novel promising topologies of power conversion systems for variable speed drives and for photovoltaic installations. It is shown that the developed schemes and algorithms of the synchronous space-vector modulation applied for control of inverter-based systems provide continuous synchronization and symmetry of the basic voltage waveforms of systems during the whole control range. It provides minimization of even harmonics and undesirable subharmonics (of the fundamental frequency) in spectra of the basic voltages of systems, leading to reducing the losses in the systems and to increasing their efficiency. Based on a comparative analysis of the integral spectral characteristics of the phase voltage of the systems, recommendations are formulated for the rational choice of schemes and algorithms of the synchronous space-vector modulation for the relevant installations, depending on the modes of their operation.
31
Moon, Kyeong-Rok, i Dong-Myung Lee. "Analysis of Rotor Position Detection Performance According to the Frequency of Square Waveform Voltage in the Harmonic Injection Sensorless Method through HILS". Processes 9, nr 12 (16.12.2021): 2267. http://dx.doi.org/10.3390/pr9122267.
Pełny tekst źródłaStreszczenie:
In this paper, the rotor position estimation performance of the sensorless scheme for permanent magnet synchronous motors (PMSMs) implemented through the injection of high-frequency square-wave voltage according to the frequency of the square-wave voltage is presented through HILS (Hardware In the Loop Simulation) experiments. An inverter using an IGBT device usually has a switching frequency of around 15 kHz. On the other hand, GaN devices that can be switched on and off at frequencies higher than 100 kHz have been recently developed, and research is being actively conducted to apply GaNs to a variable speed system. The purpose of this study is to conduct HILS experiments to analysis the rotor position estimation ability of the sensorless technique in cases where a high switching frequency was applied, such as GaN devices, with that of a system having a usual switching frequency, such as IGBT. In the HILS system used in this study, an inverter and motor model implemented with Simulink are located in a real-time simulator. A sensorless motor control method was implemented with an FPGA control board, which includes a PWM interrupt service routine of 100 kHz frequency and a harmonic injection and position detection algorithm. The HILS experiments show rotor position detection errors according to the various frequency of the harmonic voltage injected for estimating the rotor position with a PWM frequency of 100 kHz cases. According to the experimental results, good position estimation was possible not only when the harmonic of 10 kHz corresponding to 1/10 of the PWM frequency was injected, but also when the harmonic of 1 kHz corresponding to 1/100 of the PWM frequency was injected. The experiments suggest that position estimation errors decrease as the frequency of the harmonic voltage increases, and, based on the foregoing, it is thought that the application of a GaN device capable of realizing a high switching frequency in a variable speed drive system can be another advantage.
32
Hu, Ting, Hongyi Wan i Huageng Luo. "Vibration-based synchronous sampling and its application in wind-turbine drive-train-condition monitoring". Clean Energy 5, nr 1 (1.03.2021): 79–92. http://dx.doi.org/10.1093/ce/zkaa023.
Pełny tekst źródłaStreszczenie:
Abstract Utilizing shaft-speed information to analyse vibration signals is an important method for fault diagnosis and condition monitoring of rotating machineries, especially for those running at variable speeds. However, in many cases, shaft-speed information is not always available, for a variety of reasons. Fortunately, in most of the measurements, the shaft-speed information is embedded in the vibration response in many different forms, such as in the format of the fundamental shaft-rotation-frequency response and its harmonics, and the gear-meshing-frequency response and its harmonics, etc. Proper signal processing can be used to extract the shaft instantaneous speed from the measured vibration responses. In existing instantaneous shaft-speed-identification methods, a narrow-bandpass filtering technique is used explicitly or implicitly. In a complex gearbox system, such as that used in a wind turbine, the gear-meshing-response component could be modulated by many other shaft speeds, due to the configuration of the gearbox or due to the existence of component damage. As a result, it is very difficult to isolate a single vibration-response component for instantaneous shaft-speed detection. In this paper, an innovative approach is presented. The instantaneous shaft speed is extracted based on maxima tracking from the vibration-response spectrogram. A numerical integration scheme is employed to obtain the shaft instantaneous phase. Digital-domain synchronous resampling is then applied to the vibration data by using the instantaneous phase information. Due to the nature of noise suppression in the numerical integration, the accuracy of synchronous sampling is greatly improved. This proposed approach demonstrates the feasibility and engineering applicability through a controlled laboratory test case and two field wind-turbine cases. More detailed results and conclusions of this research are presented at the end of this paper.
33
Vanin, V., i M. Kruhol. "HYDRAULIC MODELS IN THE PROBLEMS OF THERMAL POWER PLANT AUXILIARY ENERGY EFFICIENCY IMPROVEMENT". Journal of Numerical and Applied Mathematics, nr 1 (135) (2021): 36–42. http://dx.doi.org/10.17721/2706-9699.2021.1.04.
Pełny tekst źródłaStreszczenie:
The work is devoted to the study of thermal power plants auxiliary energy efficiency. The main mechanisms in the auxiliary systems are centrifugal mechanisms that work in complex hydraulic networks with variable productivity. The main ways to adjust the parameters of the centrifugal mechanisms are to change the speed of rotor rotation, change the guide vane angle and throttle. The operation mode of a complex hydraulic network which includes a group of centrifugal mechanisms with a mixed connection scheme is analyzed. The system of equations which characterize the hydraulic system has been obtained on the basis of Kirchhoff's laws. The centrifugal mechanisms' operating characteristics are given by approximation dependences obtained with the method of least squares and similarity laws. To analyze efficiency of different methods of centrifugal mechanisms parameters regulation, optimal control problems were set and solved. The constraints for the problems are a system of equations that describe the hydraulic system operation and technical constraints that depend on the control method. Through solving the problems, values of the optimal parameters and weighted average efficiency of the group mechanisms were obtained. Studies have shown that the most effective way to regulate the centrifugal mechanisms parameters is to use an individual frequency drive, the least effective is to use only changing angle of centrifugal mechanism's guide vane. Utilization of group control is highly efficient and not inferior to individual frequency drive. However, this statement is correct under condition of the operating characteristics agreement with the centrifugal mechanisms’ operating modes similarity.
34
Kulinich, Yu M., S. A. Shukharev i A. V. Gulyaev. "Increasing the energy efficiency of auxiliary machines of AC electric locomotive". VNIIZHT Scientific Journal 80, nr 5 (26.10.2021): 276–84. http://dx.doi.org/10.21780/2223-9731-2021-80-5-276-284.
Pełny tekst źródłaStreszczenie:
Currently, an asynchronous variable frequency drive based on semiconductor converters is widely used due to the relative simplicity and reliability of the design. The use of digital microprocessor systems ensures high accuracy and flexibility of drive control. On the domestic rolling stock, the widespread introduction of asynchronous motors began to replace DC traction motors with sequential excitation. In particular, scalar-controlled asynchronous motors are used on serially produced 2TE25A diesel locomotives and EP20 electric locomotives. The auxiliary asynchronous machines of these locomotives are controlled by the vector control method. The use of a new type of engine on the rolling stock makes it possible to achieve a significant increase in the quality of consumed energy and reduce the consumption of electricity for traction of trains. Ensuring the energy efficiency of the drive in a wide range of loads requires further research. In this regard, the issue of saving energy resources becomes very urgent. The article proposes a vector control scheme for asynchronous motors of auxiliary machines of an electric locomotive, which implements an extreme method of control according to the criterion of minimizing the consumed current. The analysis of the engine operation is carried out based on its mathematical model in a rotating coordinate system d — q, which is implemented in the MatLab/Simulink software package. As a result of simulation modeling, it was found that the extreme control system with a variable step allows for each fixed value of the electromagnetic moment of the motor in the minimum time to find the optimal (extreme) value of the magnetic flux of the motor rotor, which corresponds to the minimum value of the stator current. The developed model of the motor with vector control is supplemented with an extreme regulator device, which allows achieving the best energy performance of the motor and reducing electrical losses in all operating modes with a minimum search time. The presented research results can be used in the development of energy-saving control systems for an asynchronous motor.
35
Cheng, Hsien-Chie, Yan-Cheng Liu, Hsin-Han Lin, Shian-Chiau Chiou, Chih-Ming Tzeng i Tao-Chih Chang. "Development and Performance Evaluation of Integrated Hybrid Power Module for Three-Phase Servo Motor Applications". Micromachines 14, nr 7 (30.06.2023): 1356. http://dx.doi.org/10.3390/mi14071356.
Pełny tekst źródłaStreszczenie:
This study aims to develop a 30 kHz/12 kW silicon carbide (SiC)/Si integrated hybrid power module (iHPM) for variable frequency drive applications, particularly industrial servo motor control, and, additionally, to theoretically and experimentally assess its dynamic characteristics and efficiency during operation. This iHPM integrates a brake circuit, a three-phase Si rectifier, and a three-phase SiC inverter within a single package to achieve a minimal current path. A space-vector pulse width modulation (SVPWM) scheme is used to control the inverter power switches. In order to reduce parasitic inductance and power loss, an inductance cancellation design is implemented in the Si rectifier and SiC inverter. The switching transients and their parasitic effects during a three-phase operation are assessed through an electromagnetic-circuit co-simulation model, by which the power loss and efficiency of the iHPM are estimated. The modeled parasitic inductance of the inverter is validated through inductance measurement, and the effectiveness of the simulated results in terms of switching transients and efficiency is verified using the experimental results of the double pulse test and open-loop inverter operation, respectively. In addition, the power loss and efficiency of the SiC MOSFET inverter are experimentally compared against those of a commercial Si IGBT inverter.
36
Шевченко, І. С., Є. С. Руднєв i Ю. А. Романченко. "Modeling of the electric drive of the main motion of the rolling cage as a multi-mass electromechanical system". ВІСНИК СХІДНОУКРАЇНСЬКОГО НАЦІОНАЛЬНОГО УНІВЕРСИТЕТУ імені Володимира Даля, nr 4(268) (10.06.2021): 30–34. http://dx.doi.org/10.33216/1998-7927-2021-268-4-30-34.
Pełny tekst źródłaStreszczenie:
The model of rolling stand of a thick-plate rolling mill 3000 has been designed in the work in order to determine the oscillations frequencies that occur during operation, the effect of their amplitude on the dynamic deviations of the speed of the working body from the specified one.Presented results of the research dynamic to rolling cage 3000 at presentation her as seven masses electromechanic system. Shown influence clearance in mechanical issue on dynamic of the mechanism.The research by the method of mathematical modeling in the design and operation of mechanical equipment is substantiated.The design diagram of mechanical part of the electromechanical system is presented.Using the simulation results it was confirmed that the influence of internal viscous friction in shafting on the oscillation damping is not significant in relation to the damping properties of electric drive.Therefore, in the first approximation, it can be ignored. The electric drive of the rolling stand was considered as a TP-D system with speed and current regulators at their standard settings to the modular optimum. To reduce the magnitude of the elastic moments in the kinematic chain of the stand the armature current intensity generator in the electric drive is used.Simulation of the processes was carried out in Simulink of the MATLAB package.Thestand model is designed according to design scheme and reflects the branching into two channels with their combination through an elastic element – the material that is rolled.Based on real geometry and taking into account the properties of material the stiffness of shafts of mechanical transmissions were calculated.The model was set to a rolling program with a variable speed – in order to compensate the thickness difference, which corresponds to modern technological trends.Comparing the simulation results, it was found that the presence of a gap provokes the appearance of self-oscillations, the damping of which in a real mechanical system will occur due to damping properties of the shafts.The damping of oscillations takes place due to the damping properties of the electric drive. The appearance of a gap in the spindles leads to an increase in the system vibration frequency (70-80 Hz).
37
Brooks, D. M. "Variable Frequency AC Drive Systems". IEE Review 34, nr 10 (1988): 414. http://dx.doi.org/10.1049/ir:19880167.
Pełny tekst źródła
38
Ng’ang’a, Emmah Wanjiku, i Martine Oleche Odhiambo. "Drivers of Health Insurance Coverage in Low Income Settlements: A Case of Kibera Informal Settlement, Nairobi County, Kenya". European Scientific Journal, ESJ 19, nr 18 (30.06.2023): 94. http://dx.doi.org/10.19044/esj.2023.v19n18p94.
Pełny tekst źródłaStreszczenie:
Insurance is critical for any country's economic growth and development to be sustainable. In rural areas of Kenya, among the illiterate, unemployed, poor, and vulnerable in society, health insurance adoption is extremely low. This paper focuses on determining the drivers for health insurance uptake among low-income populations in Kibera, Nairobi County. Semi structured questionnaires were administered to households located in Kibera informal settlements to collect data. The Yamane (1967) formula was used to select the sample size. Simple random sampling was adopted in selecting 399 respondents. Both descriptive and inferential analysis were conducted. The binary probit regression model was employed. Health insurance ownership was used as the dependent variable while age, gender, marital status, household size, school attainment, occupation, income levels, religion, cultural beliefs, frequency of hospital visits, cost of premiums, and pre-existing illness were used as the independent variables. Findings revealed that only 27.6 percent of the respondents had health insurance coverage. The findings further revealed that occupation, income levels, and religion significantly influence health insurance ownership among low-income populations in Kibera, Nairobi. Public health insurance cover was the most owned type of health insurance scheme. Recommendations were highlighted for the ministry of health and other relevant stakeholders to raise knowledge on the various health insurance options available and improve flexibility of the products to drive insurance uptake. In addition, national and county governments need to develop programmes and policies that could empower households in the informal settlements. Further, it is necessary for the government to subsidise the cost of acquiring public health insurance covers since this would encourage uptake among low-income families. The ministry of health should also work in conjunction with various religious denominations to campaign for uptake of health insurance among the poor.
39
Kennedy, J. "Variable Frequency AC Motor Drive Systems". Power Engineering Journal 3, nr 2 (1989): 103. http://dx.doi.org/10.1049/pe:19890019.
Pełny tekst źródła
40
Yahaya, N. Z., K. M. Begam i M. Awan. "Comparative Assessment of Gate Drive Control Schemes in High Frequency Converter". Engineering, Technology & Applied Science Research 1, nr 4 (16.08.2011): 76–83. http://dx.doi.org/10.48084/etasr.22.
Pełny tekst źródłaStreszczenie:
Several gate drive control schemes are simulated and the results show that the Fixed Duty ratio (FDR) can help drive synchronous rectifier buck converter (SRBC) correctly with low dead time and hence reduce body diode conduction loss. Even though FDR is prone to cross-conduction effects, the design is simple. Apart from that, Adaptive Gate Delay (AGD) and Predictive Gate Delay (PGD) control schemes have also shown high level of efficiency. However, AGD generates more losses. Even though the total switching loss in PGD has not improved much of only 1 %, more than 82 % efficiency has been achieved in spite of the advantage in FDR and AGD schemes.
41
Aleksandrov, Yevgen, Tetyana Aleksandrova, Alexander Grigoriev i Yaroslav Morhun. "STABILITY AND VIBRATIONS OF THE ELECTRONIC CLOSED SYSTEM STABILIZING THE COURSE OF A CAR WITH A TANK". Bulletin of the National Technical University "KhPI". Series: Mathematical modeling in engineering and technologies, nr 1 (5.03.2021): 44–63. http://dx.doi.org/10.20998/2222-0631.2020.01.04.
Pełny tekst źródłaStreszczenie:
To describe the disturbed movement of a car with a tank, a discrete mathematical model has been compiled, which allows one to take into account the oscillations of the free surface of the liquid and determine their effect on the directional stability of the car during uniform movement and during emergency braking. Linearization is carried out and an equation is obtained for the natural frequencies of oscillations of the electrohydromechanical system, which combines dynamic changes in the parameters of the movement of a car with a tank, partial layers of liquid in a tank and the operation of an electromagnetic drive of the control valve and an electronic PID controller for a two-circuit scheme to ensure directional stability. It is shown that low-frequency oscillations of the free surface of liquid lead to a significant reduction in the stability region, which indicates the need to take such oscillations into account when solving problems of analysis and synthesis of this system. It has been established that for a car with a tank, where low-frequency transverse oscillations of the liquid occur, which are accompanied by redistribution of mass and disturb the movement, an increase in the speed unambiguously leads to a deterioration in road-holding ability. This made it possible to exclude the speed from the variable parameters and significantly simplify the task. It was found that the liquid level in the tank, taking into account its connection with the maximum speed, has an ambiguous effect on the road-holding ability of the vehicle, and it is unacceptable to limit the research to calculations for 50 % of the load. Instead of this traditional simplification, it is necessary to find a line that bends from above those stability boundaries that correspond to many liquid levels from the entire range of their variation. It is shown that the dynamics of emergency braking weakly depends on the viscosity of the liquid in the tank, but with long-term continuous operation of the brake control system, self-oscillations appear in it. A method for tuning the parameters of an electronic regulator for low-amplitude self-oscillations is proposed.
42
PORZIO, ALBERTO, VIRGINIA D'AURIA, SALVATORE SOLIMENO, STEFANO OLIVARES i MATTEO G. A. PARIS. "HOMODYNE CHARACTERIZATION OF CONTINUOUS VARIABLE BIPARTITE STATES". International Journal of Quantum Information 05, nr 01n02 (luty 2007): 63–68. http://dx.doi.org/10.1142/s0219749907002529.
Pełny tekst źródłaStreszczenie:
We suggest a scheme to reconstruct the covariance matrix of continuous variable two-mode states using a single homodyne detector and a few polarization elements. Our method can be used to fully characterize the bipartite Gaussian entangled states obtained at the output of a (nondegenerate) optical parametric amplifier driven below threshold, as well as to extract relevant informations on generic bipartite states made of two frequency degenerate but orthogonally polarized modes.
43
Meshcheryakov, Victor, i Dmitriy Sibirtsev. "Synchronized Asynchronous Electric Drive with Variable-Frequency Control". Electrotechnical Systems and Complexes, nr 1(38) (2018): 4–8. http://dx.doi.org/10.18503/2311-8318-2018-1(38)-4-8.
Pełny tekst źródła
44
Zhang, Yi Fang, Xiao Qiang Yan i Qi Hui Ling. "Electromechanical Coupling Vibration of Rolling Mill Excited by Variable Frequency Harmonic". Advanced Materials Research 912-914 (kwiecień 2014): 662–65. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.662.
Pełny tekst źródłaStreszczenie:
Using torque telemetry system to test the mechanical drive system of rolling mill,it is found that the torsional vibration and current signal in the electric drive system have the same obviously vibration frequency. The model of cycloconverter, synchronous motor and mechanical drive system of rolling mill are built and analysed by Matlab/Simulink and ANSYS.The simulation results show when the harmonic torque frequency and the torsional vibration natural frequency of for mechanical drive system are equal or close, the strong torsional vibration arouse It is proved that the convertor output current harmonics can induce the electromechanical coupling vibration of main mechanical drive system under the certain conditions.
45
Ronilaya, Ferdian, i Hajime Miyauchi. "A Load Frequency Control in an Off-Grid Sustainable Power System Based on a Parameter Adaptive PID-Type Fuzzy Controller". International Journal of Emerging Electric Power Systems 15, nr 5 (1.10.2014): 429–41. http://dx.doi.org/10.1515/ijeeps-2014-0094.
Pełny tekst źródłaStreszczenie:
Abstract This paper presents a new implementation of a parameter adaptive PID-type fuzzy controller (PAPIDfc) for a grid-supporting inverter of battery to alleviate frequency fluctuations in a wind-diesel power system. A variable speed wind turbine that drives a permanent magnet synchronous generator is assumed for demonstrations. The PAPIDfc controller is built from a set of control rules that adopts the droop method and uses only locally measurable frequency signal. The output control signal is determined from the knowledge base and the fuzzy inference. The input-derivative gain and the output-integral gain of the PAPIDfc are tuned online. To ensure safe battery operating limits, we also propose a protection scheme called intelligent battery protection (IBP). Several simulation experiments are performed by using MATLAB®/SimPowersystems™. Next, to verify the scheme’s effectiveness, the simulation results are compared with the results of conventional controllers. The results demonstrate the effectiveness of the PAPIDfc scheme to control a grid-supporting inverter of the battery in the reduction of frequency fluctuations.
46
Gürbüz, Riza. "Controlling Flow Rate and Fluid Level by Variable Frequency Drive Unit". Archive of Mechanical Engineering 57, nr 4 (1.01.2010): 393–404. http://dx.doi.org/10.2478/v10180-010-0022-y.
Pełny tekst źródłaStreszczenie:
Controlling Flow Rate and Fluid Level by Variable Frequency Drive Unit The Variable Frequency Drive (VFD) is used to control the speed of the pumpmotor to attain the desired flow rate and fluid level in a fluid system. An AC drive provides efficient flow control by varying the pump-motor speed. The comparison of energy requirements and costs in a system where a throttling device is used for flow control on a centrifugal pump with the power used when an variable frequency drive (VFD) is used to control the same flow, evidently shows potential savings. In this system, AC Motor Frequency drive and static pressure transmitter, turbine type flowmeter and Analog/Digital cards, micro-control unit and computer connection are designed specially to control flow rate, fluid flow type (turbulence or laminar) and water level at the different conditions with different PID parameters.
47
Bawa, Mohd Nassurudden Bin Kader, Muhammad Mokhzaini Bin Azizan i Shamshul Bahar Yaakob. "Application of Variable Frequency Drive (VFD) on Speed Pump". Journal of Advanced Research in Dynamical and Control Systems 11, nr 12-SPECIAL ISSUE (31.12.2019): 843–51. http://dx.doi.org/10.5373/jardcs/v11sp12/20193284.
Pełny tekst źródła
48
Song, Xiao Na. "Research on Multi-Speed Control of Variable-Frequency Drive". Applied Mechanics and Materials 538 (kwiecień 2014): 425–28. http://dx.doi.org/10.4028/www.scientific.net/amm.538.425.
Pełny tekst źródłaStreszczenie:
This paper introduces a noval experimental teaching project. Different from previous experiment, in this project, three-phase motor can operate at multi-speed mode or continuously variable speed mode controlled by PLC and VFD. The obvious characteristic of the experiment is that the VFD is controlled by PLC automatically. The configuration of the experiment including hardware and software is introduced in detail. The results of the execuation of the PLC program reveals that three-phase motor can operate in two modes according to the instructions from PLC. In addition, the speed can be changed with the corresponding parameters seting. Therefore, the knowledge of PLC and VFD are combined in one teaching project, through which student can master more practical technique. The work of this paper is significant for improving the students’ comprehensive capability.
49
Nemikina, Olga V. "The Choice of Supply Cranes with Variable Frequency Drive". ELECTRICAL AND COMPUTER SYSTEMS 19, nr 95 (2.07.2015): 54–57. http://dx.doi.org/10.15276/eltecs.19.95.2015.14.
Pełny tekst źródła
50
Handayani, Sri Utami. "KARAKTERISTIK POMPA SENTRIFUGAL ALIRAN CAMPUR DENGAN VARIABLE FREQUENCY DRIVE". ROTASI 15, nr 3 (19.12.2013): 30. http://dx.doi.org/10.14710/rotasi.15.3.30-34.
Pełny tekst źródłaStreszczenie:
In an industry that uses large centrifugal pumps continuously, pump speed setting can reduce energy consumption significantly. By changing the speed of a centrifugal pump, capacity, head, and pump power required will change according to pump affinity laws. Speed of a centrifugal pump can be changed by variable frequency drive . This study aimed to investigate the characteristics of mixed flow centrifugal pumps with variable frequency drive. The results showed that 10% of maximum speed reduction can decrease power consumtion until 50%, while the increase in the efficiency is maximum 7.2%. The power reduction is different for different speed reduction. In a dynamic head dominated system the efficiency will remain constant during speed reduction while in static head dominated system will change.