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    UPFC for enhancing power system reliability

    , Article IEEE Transactions on Power Delivery ; Vol. 25, issue. 4 , 2010 , p. 2881-2890 ; ISSN: 8858977 Rajabi-Ghahnavieh, A ; Fotuhi-Firuzabad, M ; Shahidehpour, M ; Feuillet, R ; Sharif University of Technology
    Abstract
    This paper discusses various aspects of unified power flow controller (UPFC) control modes and settings and evaluates their impacts on the power system reliability. UPFC is the most versatile flexible ac transmission system device ever applied to improve the power system operation and delivery. It can control various power system parameters, such as bus voltages and line flows. The impact of UPFC control modes and settings on the power system reliability has not been addressed sufficiently yet. A power injection model is used to represent UPFC and a comprehensive method is proposed to select the optimal UPFC control mode and settings. The proposed method applies the results of a contingency... 

    Robust analysis and design of power system load frequency control using the Kharitonov's theorem

    , Article International Journal of Electrical Power and Energy Systems ; Vol. 55, issue , 2014 , p. 51-58 Toulabi, M. R ; Shiroei, M ; Ranjbar, A. M ; Sharif University of Technology
    Abstract
    This paper presents a robust decentralized proportional-integral (PI) control design as a solution of the load frequency control (LFC) in a multi-area power system. In the proposed methodology, the system robustness margin and transient performance are optimized simultaneously to achieve the optimum PI controller parameters. The Kharitonov's theorem is used to determine the robustness margin, i.e., the maximal uncertainty bounds under which the stable performance of the power system is guaranteed. The integral time square error (ITSE) is applied to quantify the transient performance of the LFC system. In order to tune the PI gains, the control objective function is optimized using the... 

    Robust non-fragile fractional order PID controller for linear time invariant fractional delay systems

    , Article Journal of Process Control ; Vol. 24, issue. 9 , 2014 , pp. 1489-1494 Mesbahi, A ; Haeri, M ; Sharif University of Technology
    Abstract
    A fractional order PID controller is designed to stabilize fractional delay systems with commensurate orders and multiple commensurate delays, where the time delays in the system may belong to several distinct intervals. Moreover, the controller parameters should belong to given intervals. In order to stabilize the system, the D-subdivision method is employed to choose the stabilizing set of the controller parameters from their available values. Furthermore, the nearest values of the obtained stabilizing set to their mean values are selected as the controller parameters so that a non-fragile controller is concluded. Two numerical examples evaluate the proposed control design method  

    Optimal PID control of a nano-Newton CMOS-MEMS capacitive force sensor for biomedical applications

    , Article Mechanics and Industry ; Vol. 15, issue. 2 , January , 2014 , p. 139-145 Mozhdehi, R. J ; Ghafari, A. S ; Sharif University of Technology
    Abstract
    This paper presents closed loop simulation of a CMOS-MEMS force sensor for biomedical applications employing an optimal proportional-integral-derivative controller. Since the dynamic behavior of the sensor under investigation is nonlinear the iterative feedback tuning approach was proposed for optimal gains tuning of the proposed controller. Simulation results presented in this research illustrate that the proposed controller suppresses the undesired in-plane vibration induced by environment or gripper 40 times faster than the nonlinear controller proposed in the literature. To suppress the maximum input disturbance the maximum voltage was approximately 18 V which was less than the pull-in... 

    Supervisory predictive control of power system load frequency control

    , Article International Journal of Electrical Power and Energy Systems ; Vol. 61, issue , October , 2014 , p. 70-80 Shiroei, M ; Ranjbar, A. M ; Sharif University of Technology
    Abstract
    Objective: The objective of this paper is to develop a hierarchical two-level power system load frequency control. Design: At the button level, standard PI controllers are utilized to control area's frequency and tie-line power interchanges. At the higher layer, model predictive control (MPC) is employed as a supervisory controller to determine the optimal set-point for the PI controllers in the lower layer. The proposed supervisory predictive controller computes the optimal set-points such that to coordinate decentralized local controllers. Blocking and coincidence point technology is employed to alleviate the computational effort of the MPC. In order to achieve the best closed loop... 

    Modeling and control of dissolved oxygen concentration in the fermentation of glucose to gluconic acid

    , Article Periodica Polytechnica: Chemical Engineering ; Volume 57, Issue 1-2 , 2013 , Pages 63-70 ; 03245853 (ISSN) Kazemi, M. A ; Bamdad, H ; Papari, S ; Yaghmaei, S ; Sharif University of Technology
    2013
    Abstract
    Fermentation systems are often highly nonlinear, with poorly understood dynamic behaviour of the reactor. In this work, mathematical modeling of the fermentation process based on aeration rate control was performed in a semi-batch airlift loop bioreactor. The bioconversion of glucose to gluconic acid by the Aspergillus niger strain was considered in an oxygen consuming system in the liquid phase. The proper kinetic model for the bioconversion of glucose to gluconic acid was investigated using experimental data from a 40 dm3reactor. Kinetic parameter estimation was used from the literature. The model was validated by experimental data and was compared with the Monod kinetic model. The... 

    Two-level optimal load-frequency control for multi-area power systems

    , Article International Journal of Electrical Power and Energy Systems ; Volume 53, Issue 1 , December , 2013 , Pages 540-547 ; 01420615 (ISSN) Rahmani, M ; Sadati, N ; Sharif University of Technology
    2013
    Abstract
    In large-scale power systems, classical centralized control approaches may fail due to geographically distribution of information and decentralized controllers result in sub-optimal solution for load-frequency control (LFC) problems. In this paper, a two-level structure is presented to obtain optimal solution for LFC problems and also reduce the computational complexity of centralized controllers. In this approach, an interconnected multi-area power system is decomposed into several sub-systems (areas) at the first-level. Then an optimization problem in each area is solved separately, with respect to its local information and interaction signals coming from other areas. At the second-level,... 

    Robust stability check for fractional PID-based control systems

    , Article Transactions of the Institute of Measurement and Control ; Volume 35, Issue 2 , 2013 , Pages 236-246 ; 01423312 (ISSN) Akbari Moornani, K ; Haeri, M ; Sharif University of Technology
    2013
    Abstract
    This paper considers a closed-loop system consisting of a fractional/integer order system and a fractional PID controller. Assuming that the uncertain coefficients of the fractional PID controller lie in some known intervals independently (i.e. that controller is a member of an interval family), the paper presents some easy to use theorems to investigate the robust bounded-input bounded-output stability of the resultant closed-loop system. Moreover, a finite frequency bound required in drawing the related graphs has also been provided. Finally, some numerical examples are presented to illustrate the results  

    A functional model predictive control approach for power system load frequency control considering generation rate constraint

    , Article International Transactions on Electrical Energy Systems ; Volume 23, Issue 2 , 2013 , Pages 214-229 ; 20507038 (ISSN) Shiroei, M ; Ranjbar, A. M ; Amraee, T ; Sharif University of Technology
    2013
    Abstract
    In this paper, a wide area measurement, centralized, load frequency control using model predictive control (MPC) is presented for multi-area power systems. A multivariable constrained MPC was used to calculate optimal control actions including generation rate constraints. To alleviate computational effort and to reduce numerical problems, particularly in large prediction horizon, an exponentially weighted functional MPC was employed. Time-based simulation studies were performed on a three-area power system, and the results were then compared with decentralized MPC and classical PI controller. The results show that the proposed MPC scheme offers significantly better performance against load... 

    Robust multivariable predictive based load frequency control considering generation rate constraint

    , Article International Journal of Electrical Power and Energy Systems ; Volume 46, Issue 1 , March , 2013 , Pages 405-413 ; 01420615 (ISSN) Shiroei, M ; Toulabi, M. R ; Ranjbar, A. M ; Sharif University of Technology
    2013
    Abstract
    In this paper, a robust multivariable Model based Predictive Control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area power system. The proposed control scheme is designed to consider multivariable nature of LFC, system uncertainty and generation rate constraint, simultaneously. A constrained MPC is employed to calculate optimal control input including generation rate constraints. Economic allocation of generation is further ensured by modification of the predictive control objective function. To achieve robustness against system uncertainty and variation of parameters, a linear matrix inequality (LMI) based approach is employed. To validate the... 

    AQM controller design for TCP networks based on a new control strategy

    , Article Telecommunication Systems ; Volume 57, Issue 4 , December , 2013 , Pages 295-311 ; 10184864 (ISSN) Kahe, G ; Jahangir, A. H ; Ebrahimi, B ; Sharif University of Technology
    Kluwer Academic Publishers  2013
    Abstract
    When the network suffers from congestion, the core or edge routers signal the incidence of congestion through the active queue management (AQM) to the sources. The time-varying nature of the network dynamics and the complex process of retuning the current AQM algorithms for different operating points necessitate the development of a new AQM algorithm. Since the non-minimum phase characteristics of the network dynamics restrict direct application of the proportional-integral-derivative (PID) controller, we propose a compensated PID controller based on a new control strategy addressing the phase-lag and restrictions caused by the delay. Based on the unstable internal dynamics caused by the... 

    Dynamic participation of wind farms in system frequency control

    , Article IEEE PES Innovative Smart Grid Technologies Conference Europe, 14 October 2012 through 17 October 2012 ; October , 2012 ; 9781467325974 (ISBN) Toulabi, M ; Ranjbar, A. M ; Karimi, H ; Shiroie, M ; Sharif University of Technology
    2012
    Abstract
    In this paper, the participation of wind farms in load frequency control (LFC) is studied. A previously proposed macromodel for the wind farm is employed to regulate its output power. The wind farm including its proposed control strategy is incorporated into the conventional LFC model. The proposed LFC structure is able to dynamically maintain the system frequency at the nominal value against the power imbalances. To achieve proper transient response, the integral control parameter of the LFC controller is optimized using the genetic algorithm (GA). To verify the effectiveness of the proposed method, several simulation case studies are carried out. The results show that the wind farm can... 

    Load-frequency control of interconnected power system using emotional learning-based intelligent controller

    , Article International Journal of Electrical Power and Energy Systems ; Volume 36, Issue 1 , March , 2012 , Pages 76-83 ; 01420615 (ISSN) Farhangi, R ; Boroushaki, M ; Hosseini, S. H ; Sharif University of Technology
    2012
    Abstract
    In this paper a novel approach based on the emotional learning is proposed for improving the load-frequency control (LFC) system of a two-area interconnected power system with the consideration of generation rate constraint (GRC). The controller includes a neuro-fuzzy system with power error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critic's stress is reduced. The convergence and performance of the proposed controller, both in presence and absence of GRC, are compared with those of proportional integral (PI), fuzzy logic (FL), and hybrid neuro-fuzzy (HNF)... 

    Fractional order model reduction approach based on retention of the dominant dynamics: Application in IMC based tuning of FOPI and FOPID controllers

    , Article ISA Transactions ; Volume 50, Issue 3 , July , 2011 , Pages 432-442 ; 00190578 (ISSN) Tavakoli Kakhki, M ; Haeri, M ; Sharif University of Technology
    2011
    Abstract
    Fractional order PI and PID controllers are the most common fractional order controllers used in practice. In this paper, a simple analytical method is proposed for tuning the parameters of these controllers. The proposed method is useful in designing fractional order PI and PID controllers for control of complicated fractional order systems. To achieve the goal, at first a reduction technique is presented for approximating complicated fractional order models. Then, based on the obtained reduced models some analytical rules are suggested to determine the parameters of fractional order PI and PID controllers. Finally, numerical results are given to show the efficiency of the proposed tuning... 

    Robust control of the variable speed wind turbines in the presence of uncertainties: A comparison between H∞ and PID controllers

    , Article Energy ; Volume 90 , October , 2015 , Pages 1508-1521 ; 03605442 (ISSN) Moradi, H ; Vossoughi, G ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    To achieve a cost-effective and reliable use of wind power generation, advanced control techniques are required. In this paper, the application of two control strategies for the improvement of wind turbine power output is investigated in the presence of model/environmental uncertainties. Rotational speed of the wind turbine and consequently its power output are controlled via manipulation of blades pitch angle (at a constant generator torque). First, the classical PID controller is designed based on root locus analysis while in the second scheme, an H∞-robust controller is designed via μ-synthesis based on DKiteration algorithm. Performance of the two controllers in tracking of the desired... 

    Optimal unified power flow controller application to enhance total transfer capability

    , Article IET Generation, Transmission and Distribution ; Volume 9, Issue 4 , 2015 , Pages 358-368 ; 17518687 (ISSN) Rajabi Ghahnavieh, A ; Fotuhi Firuzabad, M ; Othman, M ; Sharif University of Technology
    Institution of Engineering and Technology  2015
    Abstract
    For a power transfer path, total transfer capability (TTC) represents maximum power that can be transferred over the transmission system. Unified power flow controller (UPFC) is a device that can be used to increase in TTC. This study presents a new method for optimal UPFC application to minimise power loss while enhancing TTC. Based on UPFC injection model, the solution region of UPFC parameters is first found using the proposed method to maximise TTC. It then searches the solution region to find optimal UPFC control mode and setting to minimise system power loss. The proposed method is applied to the IEEE-Reliability Test System and the UPFC application impact are evaluated. Comparative... 

    UPFC for enhancing power system reliability

    , Article IEEE Transactions on Power Delivery ; Volume 25, Issue 4 , 2010 , Pages 2881-2890 ; 08858977 (ISSN) Rajabi Ghahnavieh, A ; Fotuhi Firuzabad, M ; Shahidehpour, M ; Feuillet, R ; Sharif University of Technology
    2010
    Abstract
    This paper discusses various aspects of unified power flow controller (UPFC) control modes and settings and evaluates their impacts on the power system reliability. UPFC is the most versatile flexible ac transmission system device ever applied to improve the power system operation and delivery. It can control various power system parameters, such as bus voltages and line flows. The impact of UPFC control modes and settings on the power system reliability has not been addressed sufficiently yet. A power injection model is used to represent UPFC and a comprehensive method is proposed to select the optimal UPFC control mode and settings. The proposed method applies the results of a contingency... 

    Locating and parameters setting of unified power flow controller for congestion management and improving the voltage profile

    , Article Asia-Pacific Power and Energy Engineering Conference, APPEEC, 28 March 2010 through 31 March 2010 ; March , 2010 ; 21574839 (ISSN) ; 9781424448135 (ISBN) Hashemzadeh, H ; Ehsan, M ; Sharif University of Technology
    2010
    Abstract
    This paper propose a particle swarm optimization based algorithm for locating Unified power flow controller (UPFC), as well as set its parameters, with static point of view in deregulated electricity markets in order to reduce generation cost, voltage violation and manage congestion. The modeling of UPFC has been adapted based on power injection method. In order to verify and validate the effectiveness of the proposed method, it was applied to 24-bus Reliability Test System (RTS) and the results have been discussed  

    Design of pid controller for control of speed of the robotic fish modeled by Lighthill's large amplitude elongated body theory in linear path

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings, 13 November 2009 through 19 November 2009, Lake Buena Vista, FL ; Volume 10, Issue PART A , 2010 , Pages 117-124 ; 9780791843833 (ISBN) Shahi, M ; Meghdari, A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2010
    Abstract
    Design of robotic fish based on hydrodynamics is presented and Lighthill's Large Amplitude Elongated Body Theory (LAEBT) is used for modeling of the robotic fish in linear path. A PID controller for control of speed in linear path is designed and simulations are presented which shows its effectiveness for speed control of the robotic fish. It has been shown that in perspective of used approximate LAEBT model, the used control law maintains kinematic parameters and therefore, the associated efficiency will be maintained  

    A cost/worth approach to evaluate UPFC impact on ATC

    , Article Journal of Electrical Engineering and Technology ; Vol. 5, issue. 3 , 2010 , p. 389-399 ; ISSN: 19750102 Rajabi Ghahnavieh, A ; Fotuhi Firuzabad, M ; Shahidehpour, M ; Feuillet, R ; Sharif University of Technology
    Abstract
    Available transfer capability (ATC) is a measure of the transfer capability remaining in a transmission system. Application of unified power flow controllers (UPFCs) could have positive impacts on the ATC of some paths while it might have a negative impact on the ATC of other paths. This paper presents an approach to evaluate the impacts of UPFCs on the ATC from a cost/worth point of view. The UPFC application worth is considered as the maximum cost saving in enhancing the ATC of the paths due to the UPFC implementation. The cost saving is considered as the cost of optimal application of other system reinforcement alternatives (except for UPFC) to reach the same ATC level obtained by UPFC...