The Experts below are selected from a list of 1019022 Experts worldwide ranked by ideXlab platform
Rahmat-allah Hooshmand - One of the best experts on this subject based on the ideXlab platform.
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adaptive filter design based on the lms algorithm for delay elimination in tcr fc Compensators
Isa Transactions, 2011Co-Authors: Rahmat-allah Hooshmand, Mahdi Torabian EsfahaniAbstract:Thyristor controlled reactor with fixed capacitor (TCR/FC) Compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such Compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR Compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC Compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC Compensator efficiently eliminated delay in the response and improved the performance of the Compensator in the power system.
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Adaptive filter design based on the LMS algorithm for delay elimination in TCR/FC Compensators.
ISA Transactions, 2011Co-Authors: Rahmat-allah Hooshmand, Torabian EsfahaniAbstract:Thyristor controlled reactor with fixed capacitor (TCR/FC) Compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such Compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR Compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC Compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC Compensator efficiently eliminated delay in the response and improved the performance of the Compensator in the power system.
Mahdi Torabian Esfahani - One of the best experts on this subject based on the ideXlab platform.
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adaptive filter design based on the lms algorithm for delay elimination in tcr fc Compensators
Isa Transactions, 2011Co-Authors: Rahmat-allah Hooshmand, Mahdi Torabian EsfahaniAbstract:Thyristor controlled reactor with fixed capacitor (TCR/FC) Compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such Compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR Compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC Compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC Compensator efficiently eliminated delay in the response and improved the performance of the Compensator in the power system.
Torabian Esfahani - One of the best experts on this subject based on the ideXlab platform.
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Adaptive filter design based on the LMS algorithm for delay elimination in TCR/FC Compensators.
ISA Transactions, 2011Co-Authors: Rahmat-allah Hooshmand, Torabian EsfahaniAbstract:Thyristor controlled reactor with fixed capacitor (TCR/FC) Compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such Compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR Compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC Compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC Compensator efficiently eliminated delay in the response and improved the performance of the Compensator in the power system.
Galal Ali Hassaan - One of the best experts on this subject based on the ideXlab platform.
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Tuning of a Feedforward Lag-Lead Second-Order Compensator used with a Highly Oscillating Second-order Process
viXra, 2016Co-Authors: Galal Ali HassaanAbstract:Lag-lead Compensators are well known in automatic control engineering. They have 4 parameters to be adjusted (tuned) for proper operation. The frequency response of the control system or the root locus plot are traditionally used to tune the Compensator in a lengthy procedure. A highly oscillating second-order process has a time response to a unit step input of 85.4 % maximum overshoot and about 6 seconds settling time is controlled using a lag-lead Compensator (through simulation). The lag-lead Compensator is tuned by minimizing the sum of time multiplied by the absolute error (ITAE) of the control system using MATLAB. Three functional constrains are used to control the performance of the lag-lead compensated control system. The result was reducing the process oscillation to 6.926 % overshoot and a 1.413 seconds settling time. The steady-state characteristics of closed-loop control system using the lag-lead Compensator were excellent. It is possible reduce the steady-state error to any desired value through one of the Compensator parameters.
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Robustness of Feedforward Notch and Sallen-Key Compensators used with Second-Order Process
2015Co-Authors: Galal Ali HassaanAbstract:Copyright © 2014 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT: Robustness is one of the requirements used in controllers and Compensators design. This paper examines the robustness of a Notch and a Sallen-Key Compensator when used to control a highly oscillating second-order process. A variation of ± 20 % in process parameters is considered through simulation to study its effect on the system performance parameters using the tuned Compensators. With a feedforward notch Compensator, the variation in process damping ratio has small effect on the settling time, maximum percentage overshoot, and phase margin of the control system, while the change in the process damping ratio has a clear effect on the control system performance. For a negative change in the process parameters, the control system is unstable. With the Sallen-Key Compensator, the control system is stable for the whole range of the process parameters variation ( ± 20 %). The change in the process damping ratio has a minor effect on the control system settling time, maximum percentage overshoot and phase margin. The change in the process natural frequency has a minor effect on the control system settling time and maximum percentage overshoot. The phase margin changes in the range 40-47 degrees corresponding to the ± 20 % change in process natural frequency
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TUNING OF A FIRST-ORDER LAG-LEAD Compensator USED WITH A VERY SLOW SECOND-ORDER PROCESS
International Journal of Advances in Engineering & Technology, 2015Co-Authors: Galal Ali HassaanAbstract:Lag-lead Compensators are well known in automatic control engineering. They have 3 or 4 parameters to be adjusted (tuned) for proper operation depending on the Compensator order. The frequency response of the control system or the root locus plot are traditionally used to tune the Compensator in a lengthy procedure. A selected very slow second-order process has a time response to a unit step input of 150 seconds settling time is controlled using a first-order lag-lead Compensator (through simulation). The lag-lead Compensator is tuned by minimizing the sum of square of errors of the control system using MATLAB. Four functional constrains are used to control the performance of the lag-lead compensated control system. The result was reducing the settling time to only 0.666 seconds. The steady-state characteristics of closed-loop control system using the first-order lag-lead Compensator were excellent. It was possible reduce the steady-state error to less than 0.01 using the tuned first-order lag-lead Compensator.
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Robustness of Feedforward Notch and Sallen-Key Compensators used with Second-Order Process
International Journal of Innovation and Applied Studies, 2014Co-Authors: Galal Ali HassaanAbstract:Robustness is one of the requirements used in controllers and Compensators design. This paper examines the robustness of a Notch and a Sallen-Key Compensator when used to control a highly oscillating second-order process. A variation of
C. De Wagter - One of the best experts on this subject based on the ideXlab platform.
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The value of EDR2 film dosimetry in Compensator-based intensity modulated radiation therapy
Physics in medicine and biology, 2007Co-Authors: R. P. Srivastava, C. De WagterAbstract:Radiographic or silver halide film is a well-established 2D dosimeter with an unquestioned spatial resolution. But its higher sensitivity to low-energy photons has to be taken into consideration. Metal Compensators or physical modulators to deliver intensity modulated radiation therapy (IMRT) are known to change the beam energy spectrum and to produce scattered photons and contaminating electrons. Therefore the reliability of film dosimetry in Compensator-based IMRT might be questioned. Conflicting data have been reported in the literature. This uncertainty about the validity of film dosimetry in Compensator-based IMRT triggered us to conduct this study. First, the effect of MCP-96 Compensators of varying thickness on the depth dose characteristics was investigated using a diamond detector which has a uniform energy response. A beam hardening effect was observed at 6 MV that resulted in a depth dose increase that remained below 2% at 20 cm depth. At 25 MV, in contrast, beam softening produced a dose decrease of up to 5% at the same depth. Second, dose was measured at depth using EDR2 film in perpendicular orientation to both 6 MV and 25 MV beams for different Compensator thicknesses. A film dose underresponse of 1.1% was found for a 30 mm thick block in a 25 MV beam, which realized a transmission factor of 0.243. The effect induced by the Compensators is higher than the experimental error but still within the accepted overall uncertainty of film dosimetry in clinical IMRT QA. With radiographic film as an affordable QA tool, the physical Compensator remains a low threshold technique to deliver IMRT.
