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Articles 1 - 20 of 20
Full-Text Articles in Engineering
Polar Fuzzy Logic Based Power System Stabilizer, D. K. Chaturvedi
Polar Fuzzy Logic Based Power System Stabilizer, D. K. Chaturvedi
D. K. Chaturvedi Dr.
A neuro fuzzy logic based adaptive power system stabilizer (AFPSS) has been developed using angularspeed deviation and angular acceleration as the input variables. It consists of two main parts, namely, fuzzylogic controller (FLC) and generalized neuron (GN) based identifier. The inference mechanism of the fuzzylogic controller is represented by rule-base and a data-base. Three parameters have been introduced to tunethe FPSS. These parameters are decided on the basis of GN-identifier output and present system conditions.This mechanism of tuning the AFPSS makes the fuzzy logic based power system stabilizer adaptive tochanges with the operating conditions. Therefore, the degradation of the system …
Power Handling And Related Frequency Scaling Advantages In Piezoelectric Aln Contour-Mode Mems Resonators, Chengjie Zuo, Matteo Rinaldi, Gianluca Piazza
Power Handling And Related Frequency Scaling Advantages In Piezoelectric Aln Contour-Mode Mems Resonators, Chengjie Zuo, Matteo Rinaldi, Gianluca Piazza
Chengjie Zuo
This paper reports on the analytical modeling and experimental verification of the mechanically-limited power handling and nonlinearity in piezoelectric aluminum nitride (AlN) contour-mode resonators (CMR) having different electrode configurations (thickness field excitation, lateral field excitation, one-port and two-port configurations) and operating at different frequencies (177-3047 MHz). Despite its simplicity, the one-dimensional analytical model fits the experimental behavior of AlN CMRs in terms of power handling capabilities. The model and experiment also confirm the advantage of scaling (i.e. miniaturizing) the AlN CMRs to higher frequencies at which higher critical power density can be more easily attained up to values in excess …
Parameter Identification Of Hydro Generation System With Fluid Transients Based On Improved Genetic Algorithm, Lin Gao
Lin Gao
More accurate models are adopted for dynamic stability analysis of hydro generation systems but the parameters of these models are often estimated roughly. Inaccurate parameters may decrease the analysis accuracy improved by using an accurate model. An improved genetic algorithm is proposed in this paper to estimate the parameters of a hydro generation system model which contains a series of basic differential equations to represent the flow transients more accurately. The numerical and experimental results show good accordance between the actual systems and the identification results.
Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Chengjie Zuo
This paper reports on the demonstration of a new class of ultra-thin (250 nm thick) Super High Frequency (SHF) AlN piezoelectric two-port resonators and filters. A thickness field excitation scheme was employed to excite a higher order contour extensional mode of vibration in an AlN nano plate (250 nm thick) above 3 GHz and synthesize a 1.96 GHz narrow-bandwidth channel-select filter. The devices of this work are able to operate over a frequency range from 1.9 to 3.5 GHz and are employed to synthesize the highest frequency MEMS filter based on electrically self-coupled AlN contour-mode resonators. Very narrow bandwidth (~ …
Demonstration Of Inverse Acoustic Band Gap Structures In Aln And Integration With Piezoelectric Contour Mode Transducers, Nai-Kuei Kuo, Chengjie Zuo, Gianluca Piazza
Demonstration Of Inverse Acoustic Band Gap Structures In Aln And Integration With Piezoelectric Contour Mode Transducers, Nai-Kuei Kuo, Chengjie Zuo, Gianluca Piazza
Chengjie Zuo
This paper presents the first design and demonstration of a novel inverse acoustic band gap (IABG) structure in aluminum nitride (AlN) and its direct integration with piezoelectric contour-mode transducers. The experimental results indicate that the IABG structure has a stop band from 185 MHz to 240 MHz and is centered around 219 MHz with maximum rejection of 30 dB. The ABG-induced phonon scattering causes a frequency band gap that prohibits the propagation of certain acoustic wavelengths. In this work, the IABG unit cell consists of a high acoustic velocity (V) center material, which is formed by 2-μm-thick AlN sandwiched by …
A New Framework For Power System Identification Based On An Improved Genetic Algorithm, Lin Gao
A New Framework For Power System Identification Based On An Improved Genetic Algorithm, Lin Gao
Lin Gao
Accuracy parameters of power system model are of great importance in stability and security evaluation or simulation. Some of the conventional methods may have inadequate adaptability or effectiveness for identification of different power systems. A general framework for power system identification is proposed based on an improved genetic algorithm with a logarithmic fitness function and an adaptive searching space. It can be used for most power system models (linear or nonlinear) and can readily be performed on different models just by rebuilt corresponding map lists between the parameters and the coefficients of the general model. The numerical experiment and practical …
Proceedings Of The Scientific Conference On Energy And It At Alvsjo Fair, Stockholm March 11-12, 2009 In Connection With The “Energitinget 2009, Dr. Erik Dahlquist, Dr. Jenny Palm
Proceedings Of The Scientific Conference On Energy And It At Alvsjo Fair, Stockholm March 11-12, 2009 In Connection With The “Energitinget 2009, Dr. Erik Dahlquist, Dr. Jenny Palm
Dr. Erik Dahlquist
This book contains the proceedings from the Energy and IT conference at Alvsjo Energy conference "Energitinget" arranged by Swedish Energy Agency, with approximately 2500 visitors. The papers contain both technical and social science papers, relating to both energy efficiency in buildings and in industry.
Aln Contour-Mode Resonators For Narrow-Band Filters Above 3 Ghz, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Aln Contour-Mode Resonators For Narrow-Band Filters Above 3 Ghz, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza
Chengjie Zuo
This paper reports on the design and experimental verification of a new class of thin-film (250 nm) Super High Frequency (SHF) laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions in order to excite a contour-extensional mode of vibration in nano features of an ultra-thin (250 nm) Aluminum Nitride (AlN) film. In this first demonstration two-port resonators vibrating up to 4.5 GHz were fabricated on the same die and attained electromechanical coupling, kt2, in excess of …
Demonstration Of Inverse Acoustic Band Gap Structures In Aln And Integration With Piezoelectric Contour Mode Wideband Transducers, Nai-Kuei Kuo, Chengjie Zuo, Gianluca Piazza
Demonstration Of Inverse Acoustic Band Gap Structures In Aln And Integration With Piezoelectric Contour Mode Wideband Transducers, Nai-Kuei Kuo, Chengjie Zuo, Gianluca Piazza
Chengjie Zuo
This paper presents the first design and demonstration of a novel inverse acoustic band gap (IABG) structure in aluminum nitride (AlN) and its direct integration with contour-mode wideband transducers in the Very High Frequency (VHF) range. This design implements an efficient approach to co-fabricate in-plane AlN electro-acoustic transducers with bulk acoustic waves (BAWs) IABG arrays (10x10). The IABG unit cell consists of a cylindrical high acoustic velocity (V) media, which is held by four thin tethers, surrounded by a low acoustic velocity matrix (air). The center media is formed by 2-μm-thick AlN, which is sandwiched by 200-nm-thick top and bottom …
1.05 Ghz Mems Oscillator Based On Lateral-Field-Excited Piezoelectric Aln Resonators, Chengjie Zuo, Jan Van Der Spiegel, Gianluca Piazza
1.05 Ghz Mems Oscillator Based On Lateral-Field-Excited Piezoelectric Aln Resonators, Chengjie Zuo, Jan Van Der Spiegel, Gianluca Piazza
Chengjie Zuo
This paper reports on the first demonstration of a 1.05 GHz microelectromechanical (MEMS) oscillator based on lateral-field-excited (LFE) piezoelectric Aluminum Nitride (AlN) contour-mode resonators. The oscillator shows a phase noise level of –81 dBc/Hz at 1 kHz offset frequency and a phase noise floor of –146 dBc/Hz, which satisfies the GSM requirements of Ultra High Frequency (UHF) local oscillators (LO). The circuit was fabricated in the AMIS 0.5 μm CMOS process, with the oscillator core consuming only 3.5 mW static power. A simple two-mask process was used to fabricate the LFE AlN resonators from 843 MHz to 1.64 GHz with …
Target Detection In Single- And Multiple-View Through-The-Wall Radar Imaging, Christian Debes, Moeness G. Amin, Abdelhak M. Zoubir
Target Detection In Single- And Multiple-View Through-The-Wall Radar Imaging, Christian Debes, Moeness G. Amin, Abdelhak M. Zoubir
Christian Debes
A detector of targets behind walls and in enclosed structures is presented. The detector is applied to through-the-wall radar images obtained by wideband delay and sum beamforming. We consider the detection problem using single- and multiple-view imaging. The statistics of noise, clutter, and target images are examined and formulated using sample scenes. The effects of wall parameter errors on the image statistics are shown. An iterative detection scheme, which adapts itself to the image statistics, is presented. The proposed detection schemes are evaluated using real data.
Effect Of Salts On The Electrospinning Of Poly(Vinyl Alcohol), Jonathan J. Stanger, Nick Tucker, Mark P. Staiger, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Nigel Larsen
Effect Of Salts On The Electrospinning Of Poly(Vinyl Alcohol), Jonathan J. Stanger, Nick Tucker, Mark P. Staiger, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Nigel Larsen
Jonathan J Stanger
Fibres with a diameter in the nanometer range were electrospun from aqueous poly(vinyl alcohol) (PVOH). In order to improve the mass deposition rate and decrease the final fibre diameter salts (NaCl, LiCl, LiBr and LiF) were added to the solution. The aim was to increase the charge density and hence increase the electrostatic forces on the fluid. It was found that with increasing salt concentration the charge density did increase. However the mass deposition rate was found to decrease and the final fibre diameter was found to increase. The decrease in mass deposition rate is explained by considering the concept …
Effect Of Charge Density On The Taylor Cone In Electrospinning, Jonathan J. Stanger, Nick Tucker, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Mark P. Staiger
Effect Of Charge Density On The Taylor Cone In Electrospinning, Jonathan J. Stanger, Nick Tucker, Kerry Kirwan, Stuart Coles, Daniel Jacobs, Mark P. Staiger
Jonathan J Stanger
A detailed understanding of charge density and its origins during the electrospinning process is desirable for developing new electrospinnable polymer-solvent systems and ensuring mathematical models of the process are accurate. In this work, two different approaches were taken to alter the charge density in order to measure its effect on the Taylor cone, mass deposition rate and initial jet diameter. It was found that an increase in charge density results in a decrease in the mass deposition rate and initial jet diameter. A theory is proposed for this behaviour in that an increase in charge density leads to the tip …
The Effect Of Electrode Configuration And Substrate Material On The Mass Deposition Rate Of Electrospinning, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Nigel Larsen, Mark P. Staiger, Roger Reeves
The Effect Of Electrode Configuration And Substrate Material On The Mass Deposition Rate Of Electrospinning, Jonathan J. Stanger, Nick Tucker, Andrew Wallace, Nigel Larsen, Mark P. Staiger, Roger Reeves
Jonathan J Stanger
Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution. A positive high voltage relative to the collecting electrode significantly increased the fibre deposition rate. Electron microscopy showed that approximately half of the increase in fibre mass was due to thicker fibres being deposited. The current flowing from the grounded electrode was measured to determine the charge carried on the PVOH jet. This showed that for a positive voltage charging condition there is a much larger current and hence more charge carriers generated in the PVOH solution. As a result, more mass is ejected from the Taylor …
Voltage Sag Effects On A Refinery With Induction Motors Loads, Tarek Ibrahim Elshennawy Dr., Amr Yehia Abou-Ghazala A. Prof., Mahmoud El-Gammal Prof.
Voltage Sag Effects On A Refinery With Induction Motors Loads, Tarek Ibrahim Elshennawy Dr., Amr Yehia Abou-Ghazala A. Prof., Mahmoud El-Gammal Prof.
Tarek Ibrahim ElShennawy
Process continuity of industrial plants (like a refinery) is subjected to several shutdowns due to voltage sags causing large induction motors (IM) to trip. In this paper, the response of induction motors to voltage sags is investigated through computer simulations using the MATLAB/SIMULINK toolbox. The simulations are verified by actual performance. The basic observed effects of voltage sags on IM are speed loss and current and torque transients associated with both voltage reduction and recovery. Results have also showed that three-phase voltage sags and sags occurring at zero crossing are the most severe events. Transient currents occurring at the instants …
Design And Implementation Of A Multi Level Three-Phase Inverter With Less Switches And Low Qutput Voltage Distortion, Saad Mekhilef
Design And Implementation Of A Multi Level Three-Phase Inverter With Less Switches And Low Qutput Voltage Distortion, Saad Mekhilef
Saad Mekhilef
This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic …
Novel Biconical Antenna Configuration With Directive Radiation, M. Shahpari, F. H. Kashani, Hossein Ameri Mahabadi
Novel Biconical Antenna Configuration With Directive Radiation, M. Shahpari, F. H. Kashani, Hossein Ameri Mahabadi
Hossein Ameri Mahabadi
In this paper a novel biconical antenna geometry has been proposed that has directive radiation pattern, higher gain and enhanced front to back ratio. Wide band performance is another characteristic of this new antenna.
Assemble A Ku-Band Frequency Synthesizer, Hossein Ameri Mahabadi, M. Moghavvemi
Assemble A Ku-Band Frequency Synthesizer, Hossein Ameri Mahabadi, M. Moghavvemi
Hossein Ameri Mahabadi
This straightforward design shows how to assemble commercial components into a low-noise 14.4-to-15.5-GHz frequency synthesizer with 625-kHz tuning steps for digital microwave radio systems.
Qualification And Provisioning Of Xdsl Broadband Lines Using A Gis Approach, John Karamitsos, Athanassios Mavridis, Paola Saletti
Qualification And Provisioning Of Xdsl Broadband Lines Using A Gis Approach, John Karamitsos, Athanassios Mavridis, Paola Saletti
John P. Karamitsos
No abstract provided.
Solar References, Djamila Rekioua