Yazar "Aygun, Hilmi" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • Küçük Resim Yok
    Öğe
    Comparison of DC link current and stator phase current in inverter switching faults detection of PMSM drives in HEVs
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2018) Aktas, Mustafa; Aygun, Hilmi
    In this paper, a robust method for detection of inverter short circuit faults in field oriented control (FOC) of permanent magnet synchronous motor (PMSM) drive that is used frequently in hybrid electric vehicles (HEV) thanks to high power density and high efficiency is introduced. In the proposed method, a fault diagnostic and protection technique is developed by using discrete wavelet transform (DWT) and artificial neural network (ANN). The Symlet2 wavelet is selected to perform stator current analysis and the DWT coefficients of the motor currents are used as inputs of ANN for detecting inverter faults in PMSM drives. In HEVs, motor faults can cause permanent damage and accidents. So the early detection of PMSM drive faults in HEV will be provided by the proposed method. For implementing this method, the Matlab program is used to process DWT of signals. DC link and phase currents are compared in inverter switch faults detection and the results show that the proposed technique is very effective for fault diagnostic. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.
  • Küçük Resim Yok
    Öğe
    Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization
    (Univ Suceava, Fac Electrical Eng, 2012) Aygun, Hilmi; Demirel, Huseyin; Cernat, Mihai
    Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID) controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL) controller. The simulation results demonstrate some advantages of the proposed controller.
  • Küçük Resim Yok
    Öğe
    LMC-based DTC for efficiency improvement of IM drives and their electric vehicle applications
    (Springer Heidelberg, 2020) Aygun, Hilmi; Aktas, Mustafa
    Electric vehicles (EVs) with induction motor (IM) drives require energy optimization due to their limited energy storage capacity. Among the energy optimization methods currently available, a loss model-based controller (LMC) is a satisfactory technique, since it converges rapidly to an optimal operating point. Some of the simplifications applied to LMCs, such as neglecting the core loss and leakage inductances, affect IM drive performance negatively in terms of loss minimization. To overcome this problem, this paper presents an efficient LMC combined with direct torque control (DTC). The proposed method is based on the idea that the magnetizing current is much higher than the core loss current. Using the sum of the stator current and the rotor current instead of the magnetizing current, modelling the losses is simplified and the optimal stator flux is determined easily. A simulation study is carried out to evaluate the performance of the proposed scheme with an EV application during an FTP-75 urban driving cycle. A prototype 3 kW IM drive with a TMS320F28335 digital signal processor (DSP) is built to validate the simulation results. A significant efficiency improvement is obtained at low loads. Both simulation and experimental results demonstrate that the proposed DTC improves efficiency and decreases torque ripple.
  • Küçük Resim Yok
    Öğe
    Modeling railway line capacity on Karabuk - Zonguldak line
    (Gazi Univ, 2022) Akay, Mehmet Emin; Aygun, Hilmi
    In this study, passenger train operation on the single track railway on the Karabuk-Zonguldak track was examined. A solution was sought for the problems related to waiting and delays on this railway line and the optimum tariff was tried to be found. In the study, daily train capacity that can be operated on the Karabuk-Zonguldak line, where 10-station and 8 daily passenger trains with both directions are operating, was examined and a particle swarm optimization (PSO) based programming model was applied. In this model, the track of 116.6 km between Karabuk and Zonguldak is considered. The simulation study of the proposed method was carried out with the MATLAB program. As a result of the modeling, according to the data provided, the train departure times were rearranged and it was demonstrated with the simulation that 65% improvement was achieved in delays.
  • Küçük Resim Yok
    Öğe
    A Novel DTC Method with Efficiency Improvement of IM for EV Applications
    (Eos Assoc, 2018) Aygun, Hilmi; Aktas, Mustafa
    Induction motor (IM) stator flux optimization is very important in order to get increasing running distance per battery charge of electric vehicles (EVs). This study introduces a new direct torque control (DTC) method for efficiency improvement of IM in EV applications. Also, it is proposed to decrease the torque ripple of DTC based IM. Generally, loss minimization algorithms can be simplified by neglecting the core loss or the effect of leakage inductance in the motor model. However, neglecting the core loss causes an error in torque control of DTC. Beside this, exact loss minimization cannot be achieved since a large voltage drop across leakage inductance occurs especially in high-speed region. In the proposed method, the motor model is simplified by neglecting the current in the core loss resistance branch instead of neglecting the core loss and the effect of leakage inductance. The proposed method is simulated in Matlab for variable speeds and loads. Results show that it provides a significant reduction of losses and decreases the torque ripple of IM drives.
  • Küçük Resim Yok
    Öğe
    A Novel Sensorless Field Oriented Controller for Permanent Magnet Synchronous Motors
    (Ieee, 2014) Aygun, Hilmi; Gokdag, Mustafa; Aktas, Mustafa; Cernat, Mihai
    In this paper, a Particle Swarm Optimization based PI controller (PSO-PI) is used for control the speed and the torque of a Permanent Magnet Synchronous Motor (PMSM) while a Model Reference Adaptive System (MRAS) based on an Artificial Neural Network (ANN) estimation mechanism is applied to estimate sensorless the speed. In order to show the capability of the proposed PSO-PI controller, it is compared with a Fuzzy-Logic PI controller and with a classical PI controller. The simulation results prove the usefulness of the proposed PSO-PI controller.
  • Küçük Resim Yok
    Öğe
    Parameter estimation of the wind speed distribution model by dragonfly algorithm
    (Gazi Univ, Fac Engineering Architecture, 2023) Kose, Bayram; Aygun, Hilmi; Pak, Semih
    Purpose: In modelling wind speed by Weibull probability distribution function (Wpdf) for potential calculation of wind energy and wind speed characterization, the purpose of the study is to estimate the distribution parameters.Theory and Methods: The performance of the proposed method has been evaluated by comparing not only the classical methods which are the moment method (MM) and the least squares method (LSM) but also metaheuristic optimization algorithms which are Dragonfly Algorithm (DA), Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Determination coefficient (R2) and root mean square error (RMSE) were used to evaluate the performance of these parameter estimation methods. Results: Dat obtaine from 6 measurement stations were used in the study. The results show that while the DA method gives the best performance according to the determination coefficient (R2) criterion in all stations, it provides the best performance in 2 stations according to the root mean square error (RMSE) criterion. In addition, it was observed that the DA method showed better performance in all stations compared to the LSM method.Conclusion: It is seen that the proposed DA algorithm for wind energy potential calculation can be used to estimate Weibull and two-component mixed Weibull distribution parameters.