Yazar "Naveed, Ausnain" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • Küçük Resim
    Öğe
    Damping Based Relative Stability Regions in Load Frequency Control System with Plug-in Electric Vehicles and Communication Delays
    (IEEE (Institute of Electrical and Electronics Engineers), 2020) Naveed, Ausnain; Sönmez, Şahin; Ayasun, Saffet
    This paper presents a damping based stability analysis of a time delayed single-area load frequency control (LFC) system with plug-in Electric Vehicles (EVs) Aggregator by employing a graphical method. The proposed technique computes all the stabilizing gain values of Proportional Integral (PI) controller of the LFC with plug-in EVs (LFC-EVs) system. The proposed method relies on identifying stability region and the stability boundary locus in the PI controller parameter plane having user defined relative stability. These damping based stability regions are obtained and the accuracy of their Complex Root Boundary (CRB) and Real Root Boundary (RRB) is validated by an independent algorithm and time-domain simulations. Moreover, a simple and effective analytical approach known as Weighted Geometrical Center (WGC) is used for tuning the stabilizing controller parameters to achieve better system performance.
  • Küçük Resim
    Öğe
    The effect of demand response control on stability delay margins of load frequency control systems with communication time-delays
    (TÜBİTAK, 2021) Katipoğlu, Deniz; Sönmez, Şahin; Ayasun, Saffet; Naveed, Ausnain
    ThIs paper studIes the effect of dynamIc demand response (DR) control on stabIlIty delay margIns of load frequency control (LFC) systems IncludIng communIcatIon tIme-delays. A DR control loop Is Included In each control area, called as LFC-DR system and RekasIus substItutIon Is utIlIzed to IdentIfy stabIlIty margIns for varIous proportIonalIntegral (PI) gaIns and partIcIpatIon ratIos of the secondary and DR control loops. The purpose of RekasIus substItutIon technIque Is to obtaIn purely complex roots on the ImagInary axIs of the tIme-delayed LFC-DR system. ThIs substItutIon fIrst converts the characterIstIc equatIon of the LFC-DR system IncludIng delay-dependent exponentIal terms Into an ordInary polynomIal. Then the well-known Routh-HurwItz stabIlIty method Is applIed to fInd those ImagInary roots and the correspondIng stabIlIty delay margIn known as maxImal tIme-delay. Delay margIn results IndIcate that the InclusIon of DR control loop sIgnIfIcantly Increases stabIlIty delay margIn and Improves the frequency dynamIc behavIor of the LFC system IncludIng tIme-delays. TheoretIcal stabIlIty margIns are confIrmed by a proven algorIthm, quasI-polynomIal mappIng-based root fInder (QPmR) algorIthm and tIme-domaIn sImulatIons. © 2021 Turkiye Klinikleri. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Impact of electric vehicles aggregators with communication delays on stability delay margins of two-area load frequency control system
    (SAGE Publications, 2021) Naveed, Ausnain; Sönmez, Şahin; Ayasun, Saffet
    This paper investigates the impact of electric vehicles (EVs) aggregator with communication time delay on stability delay margin of a two-area load frequency control (LFC) system. A frequency-domain exact method is used to calculate stability delay margins for various values of proportional-integral (PI) controller gains. The proposed method first eliminates the transcendental terms in the characteristic equation without using any approximation and then transforms the transcendental characteristic equation into a regular polynomial using a recursive approach. The key result of the elimination process is that real roots of the new polynomial correspond to imaginary roots of the transcendental characteristic equation. With the help of new polynomial, delay-dependent system stability and root tendency with respect to the time delay is determined. An analytical formula is then developed to compute delay margins in terms of system parameters. The qualitative impact of EVs aggregator on stability delay margins is thoroughly analysed and the results are verified by time domain simulations and quasi-polynomial mapping-based root finder (QPmR) algorithm.
  • Küçük Resim Yok
    Öğe
    Impact of load sharing schemes on the stability delay margins computed by Rekasius substitution method in load frequency control system with electric vehicles aggregator
    (2020) Naveed, Ausnain; Sönmez, Şahin; Ayasun, Saffet
    The impact of load sharing between the electric vehicles (EVs) aggregator and theconventional generator on stability delay margins in a two-area load frequencycontrol (LFC) system is investigated in this work. A frequency-domain Rekasiussubstitution method is used to compute stability delay margins for different valuesof proportional-integral (PI) controller gains. The proposed method computes com-plex roots on the imaginary axis of the quasi-characteristic equation. The substitu-tion first converts the quasi-characteristic equation of the LFC with EVsaggregator (LFC-EVs) system including delay-dependent exponential terms intoan ordinary polynomial. Then, the Routh–Hurwitz stability method is applied tofind those imaginary roots and the corresponding stability delay margins. Thequalitative impact of different sharing schemes between the conventional genera-tor and EVs aggregator and the impact of EVs gains on stability delay margins arethoroughly analyzed, and the results are validated by time domain simulationsand quasi-polynomial mapping-based root finder algorithm. It is observed that forany given PI controller gains, stability delay margins decrease when the participa-tion of EVs into the frequency regulation increases.
  • Küçük Resim
    Öğe
    Stability regions in time delayed two-area LFC system enhanced by EVs
    (TÜBİTAK / Türkiye Bilimsel ve Teknik Araştırma Kurumu / Scientific and Technical research Council of Turkey, 2022) Naveed, Ausnain; Sönmez, Şahin; Ayasun, Saffet
    With the extensive usage of open communication networks, time delays have become a great concern in load frequency control (LFC) systems since such inevitable large delays weaken the controller performance and even may lead to instabilities. Electric vehicles (EVs) have a potential tool in the frequency regulation. The integration of a large number of EVs via an aggregator amplifies the adverse effects of time delays on the stability and controller design of LFC systems. This paper investigates the impacts of the EVs aggregator with communication time delay on the stability. Primarily, a graphical method characterizing stability boundary locus is implemented. The approach is based on the stability boundary locus that can be easily determined by equating the real and the imaginary parts of the characteristic equation to zero. For a given time delay, the method computes all the stabilizing proportional-integral (PI) controller gains, which constitutes a stability region in the parameter space of PI controller.The effects of communication delay and participation factor of EVs aggregator on the obtained stability regions is thoroughly examined. Results clearly illustrate that stability regions become smaller as the time delay and participation factor of EVs increase. Finally, the accuracy of region boundaries known as real root boundary and complex root boundary is confirmed by time-domain simulations along with an independent algorithm, quasipolynomial mapping-based root finder (QPmR) algorithm.