Browsing by Author "Erken F."

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Comparison of SVPWM and SPWM on PMSM Speed Control fed by PV Array with SEPIC MPPT
(2021-01-01) Sehirli E.; Shaftari S.O.; Erken F.
In this paper, speed control of PMSM that is fed by PV array on the basis of vector control is realized. Besides, switching signals for PMSM are obtained by both SVPWM and SPWM and their effect on the speed is compared. Furthermore, MPPT consisting of PO method is applied by using SEPIC DC-DC converter. This study is carried out by using Matlab/Simulink. Also, the change of irradiation level and ambient temperature of PV array are included in the study. By simulations, PMSM speed under reference and load changes, PV array power are measured and compared.
Decreasing harmonics via three phase parallel active power filter using online adaptive harmonic injection algorithm
(2018-05-01) Karaman Ö.A.; Erken F.; Cebeci M.
Three-Phase Parallel Active Power Filter (PAPF) control mechanism via a novel Adaptive Harmonic Injection (AHI) algorithm is proposed in order to filter out harmonics generated by non-linear loads and carry out reactive power compensation. The presented PAPF mechanism is composed of two stages. Before is the extraction of reference current to determine currents with harmonics. Once the reference current is determined, according to the reference current, appropriate current harmonics are injected by triggering of the inverter switches. The proper amplitude and phase values of the harmonics that will be injected are estimated online at any instant by the AHI algorithm. In this study, the sine and the cosine of the phase angle for any harmonic order is weighted by the values estimated via the AHI algorithm, thus obtaining harmonic orders at the desired amplitude and phase. Simulations are performed using various non-linear loads in order to validate the proposed method.
Design of broadband absorptive optimum frequency selective rasorber without loaded circuit elements
(2020-12-01) Özdin M.; Orak S.; Erken F.
In this work, unlike conventional ones, an optimum rasorber was designed which does not require circuit elements loaded by soldering. With high physical protection and wide absorption band, this proposed rasorber is suitable for stealthy antenna radomes. This structure is easy to manufacture as the absorption and frequency selectivity are achieved only by resistive and conductive square patch elements integrated into the dielectric layers. Firstly, using computer simulation results, predetermined value sets of equivalent circuit elements of the impedance of a frequency selective surface (FSS) are obtained depending on the dimensions in a unit cell. Then, the reflection and transmission coefficients of the whole structure are expressed as the functions of all variables in the rasorber. The transmission coefficient calculation is carried out with a newly introduced formulation. The optimum values of the variables are determined by using multi-objective optimization. A broadband rasorber prototype containing three resistive FSS and a conductive FSS is manufactured and the test results are shown quantitatively. The designed structure transmits 4.2 GHz operating frequency with slight attenuation and it provides reflection less than −10 dB in the 8–23.4 GHz band and less than −15 dB in the 8.6–21.4 GHz band.
State Estimation of Buck Converter by Using Kalman Filter
(2022-01-01) Eker K.; Cetinceviz Y.; Sehirli E.; Erken F.
This study presents buck converter modeling and estimation of state variables in noisy and noiseless environments using Kalman Filter. Firstly, the linearized state space model of the buck converter is obtained and the simulation model is created. The output voltage of the buck converter, the state variables of inductor current and capacitor voltage are estimated using the Kalman state observer. The simulations are carried out in the MATLAB/Simulink software environment. Eventually the estimation of the state variables with the Kalman filter has been verified by comparing it with the model of the converter with maximum 7.10%%, minimum 0.0% error regarding to different scenarios.