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    Battery energy storage systems and demand response applied to power system frequency control

    , Article International Journal of Electrical Power and Energy Systems ; Volume 136 , 2022 ; 01420615 (ISSN) Hosseini, S.A ; Toulabi, M ; Ashouri Zadeh, A ; Ranjbar, A. M ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    In this paper, several new control strategies for employing the battery energy storage systems (BESSs) and demand response (DR) in the load frequency control (LFC) task are proposed. In this way, first, the unit commitment problem considering the BESSs’ constraints in presence of wind farms and responsive loads is solved and the best location and the optimal size of the BESSs as well as the regulation power of the responsive loads are obtained. A rule-based plan is then suggested to improve the frequency regulation considering participation of wind farms. This plan is takes into account different states associated with power system frequency response as well as BESSs’ state of charge (SOC).... 

    Tuning the implementable structures of fractional-order PID controllers for control of FOPDT processes

    , Article Scientia Iranica ; Volume 29, Issue 2 D , 2022 , Pages 660-675 ; 10263098 (ISSN) Ashjaee, M ; Tavazoei, M. S ; Sharif University of Technology
    Sharif University of Technology  2022
    Abstract
    This study presents a set of rules for optimal tuning of a class of integer-order controllers, known as implementable fractional-order PID controllers, so that they can be employed to control First Order Plus Dead Time (FOPDT) processes. To this end, "tuning based on the implementable form of the controller"is an approach that has been applied instead of the common approach of "tuning based on the ideal form of the controller". Consequently, no contradiction is found between the behavior of the tuned controller and that of the implemented controller. Also, algebraic relations between the values of cost functions, which are defined based on Integral Square Error (ISE) and Integral Square Time... 

    Load frequency control (LFC) strategies in renewable energy‐based hybrid power systems: a review

    , Article Energies ; Volume 15, Issue 10 , 2022 ; 19961073 (ISSN) Gulzar, M. M ; Iqbal, M ; Shahzad, S ; Muqeet, H. A ; Shahzad, M ; Hussain, M. M ; Sharif University of Technology
    MDPI  2022
    Abstract
    The hybrid power system is a combination of renewable energy power plants and conventional energy power plants. This integration causes power quality issues including poor settling times and higher transient contents. The main issue of such interconnection is the frequency variations caused in the hybrid power system. Load Frequency Controller (LFC) design ensures the reliable and efficient operation of the power system. The main function of LFC is to maintain the system frequency within safe limits, hence keeping power at a specific range. An LFC should be supported with modern and intelligent control structures for providing the adequate power to the system. This paper presents a... 

    A PID controller design to suppress chatter vibrations in the turning process studying its effect in nonlinear delayed process

    , Article 10th International Conference on Modern Circuits and Systems Technologies, MOCAST 2021, 5 July 2021 through 7 July 2021 ; 2021 ; 9781665418478 (ISBN) Khajoee, M ; Moradi, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    High-quality, high-production-rate machining operations are significantly hindered by the regenerative chatter. Therefore, chatter suppression is of great significance; and active control is one of the best ways to curb it. In this paper, the orthogonal turning process is modeled as a single-degree-of-freedom system that includes the effect of tool wear; and described through a delay differential equation (DDE). Based on the model, stability lobes diagrams are obtained by the trial and error. The actuator force is the input for the control system and the tool vibration is the output. A classical PID controller is designed to improve the stability of the process and curb the self-excited... 

    Modeling and active control of chatter vibrations of piezoelectric stacked machining arm in micro-turning process

    , Article Meccanica ; Volume 55, Issue 9 , 18 July , 2020 , Pages 1707-1731 Hesabi Hesari, A ; Moradi, H ; Movahhedy, M. R ; Sharif University of Technology
    Springer  2020
    Abstract
    Self-excited vibrations known as chatter are considered as the most detrimental issue in micro-turning processes. Occurring unpredictably, they adversely affect the tool life, productivity rate and surface quality of the machining processes. In this paper, a novel machining arm is modeled as a piezoelectric stacked rod which is subjected to a chatter force in the orthogonal micro-turning process. Due to the fact that machining processes are affected by various sources of uncertainties, H∞ robust control approach is used to suppress the chatter vibrations of the machining arm in the presence of tool wear and dynamic model parameter variations. Also, input control force of the system is... 

    Delay compensation of demand response and adaptive disturbance rejection applied to power system frequency control

    , Article IEEE Transactions on Power Systems ; Volume 35, Issue 3 , 2020 , Pages 2037-2046 Hosseini, S. A ; Toulabi, M. R ; Salehi Dobakhshari, A ; Ashouri Zadeh, A ; Ranjbar, A. M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    In this paper, a modified frequency control model is proposed, where the demand response (DR) control loop is added to the traditional load frequency control (LFC) model to improve the frequency regulation of the power system. One of the main obstacles for using DR in the frequency regulation is communication delay which exists in transferring data from control center to appliances. To overcome this issue, an adaptive delay compensator (ADC) is used in order to compensate the communication delay in the control loop. In this regard, a weighted combination of several vertex compensators, whose weights are updated according to the measured delay, is employed. Generating the phase lead is the... 

    Harmonic effects optimization at a system level using a harmonic power flow controller

    , Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 28, Issue 5 , 2020 , Pages 2586-2601 Mehri, R ; Mokhtari, H ; Sharif University of Technology
    Turkiye Klinikleri  2020
    Abstract
    Increase of nonlinear loads in industries has resulted in high levels of harmonic currents and consequently harmonic voltages in power networks. Harmonics have several negative effects such as higher energy losses and equipment life reduction. To reduce the levels of harmonics in power networks, different methods of harmonic suppression have been employed. The basic idea in all of these methods is to prevent harmonics from flowing into a power network at customer sides and the point of common coupling (PCC). Due to the costs, none of the existing mitigating methods result in a harmonic-free power system. The remaining harmonic currents, which rotate in a power network according to the system... 

    The impact of demand response programs on UPFC placement

    , Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 27, Issue 6 , 2019 , Pages 4624-4639 ; 13000632 (ISSN) Sharifi Nasab Anari, A ; Ehsan, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
    Turkiye Klinikleri  2019
    Abstract
    Demand response (DR) and flexible AC transmission system (FACTS) devices can be effectively used for congestion management in power transmission systems. However, demand response program (DRP) implementation can itself affect the optimum location of FACTS devices, which is one of the main issues in power system planning. This paper investigates the impact of DRPs on unified power flow controller (UPFC) placement. The harmony search algorithm is employed to determine the optimum locations and parameter setting of UPFC in a long-term framework. The optimization problem is solved with different objectives including generation and congestion cost reduction, as well as loss reduction. In this... 

    Decentralized multivariable PID controller with pre compensator for gas turbine system

    , Article 2017 IEEE 4th International Conference on Knowledge-Based Engineering and Innovation, KBEI 2017 ; Volume 2018-January , 2018 , Pages 0074-0082 ; 9781538626405 (ISBN) Mousavi, H ; Azizi, A ; Nourisola, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In this paper, a restricted structure of PID controller is proposed for automobile gas turbine by considering a LQG cost function. So PID Controller coefficients are calculated by minimizing this cost function. One of the most important characteristics of this approach, its ability to design various structure PID controllers by solving optimization problem only for one time, moreover it can approximate main optimization problem by a repetitive Quadratic optimization Problem (QP). This approach is convex optimization and has an analytic solution; therefore its calculations are not complicated. In defined cost function, there are two weighting functions, control error and control action; they... 

    Design and assessment of variable-structure LQG PID multivariable controllers

    , Article Optimal Control Applications and Methods ; Volume 38, Issue 4 , 2017 , Pages 634-652 ; 01432087 (ISSN) Mousavi, H ; Nobakhti, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2017
    Abstract
    Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that... 

    Comment on “Design of PID controllers for interval plants with time delay”

    , Article Journal of Process Control ; Volume 44 , 2016 , Pages 160-161 ; 09591524 (ISSN) Firouzbahrami, M ; Nobakhti, A ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    In [1] three theorems are presented which relate to the problem of stabilizing PID controller design for interval time-delay plants. We present a counterexample for these results  

    Design and assessment of variable-structure LQG PID multivariable controllers

    , Article Optimal Control Applications and Methods ; 2016 ; 01432087 (ISSN) Mousavi, H ; Nobakhti, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    Control Performance Assessment (CPA) and tuning of PID controllers are studied in this paper. We propose a framework for systematic analysis of the tradeoff between the structural complexity of the controller and its performance. As the measure of the controller performance, an LQG based index is used. The problem is augmented with an additional term which forces sparsity on the complexity of a decentralized PID controller. The desired complexity is controlled via a weighting parameter which determines the cost of each additional element (i.e., P, I, and D terms). The result is a decentralized multivariable PID controller in which the complexity of each loop controller is optimized such that... 

    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... 

    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...