Browsing by Author "Sehirli E."

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Analysis of LCL Filter Topologies for DC-DC Isolated Cuk Converter at CCM Operation
(2022-01-01) Sehirli E.; Sehirli, E
In this study, the application and analysis of LCL filter topologies including an LCL, an LCL with damping, and an LCL trap filter used by a DC-DC isolated Ćuk converter operated at CCM are presented. The converter is designed for 50 W with 42 kHz switching frequency using a SiC MOSFET as a power switch. Although LCL filter topologies are commonly used with an inverter, their use in DC-DC converters has not been studied in detail. The main contribution of the paper is the application, design, and analysis of an LCL trap filter, which is not presented for a DC-DC converter in the literature, as an input filter of a DC-DC isolated Ćuk converter. For exact analysis of the effect of the filter, as a second main contribution of the paper, a state-space average mathematical model, small signal analysis of an isolated Ćuk converter for CCM operation, which was not presented before in the literature, is derived and its transfer function is obtained. In this paper, the practical design and transfer functions of LCL-based filter topologies are also presented. In order to analyze the effect of filter topologies by using linear methods including root locus and Bode graphs, the transfer function of the converter is cascaded with the transfer function of each filter separately, which is the third contribution of the paper because such analysis has not been presented in the literature. Furthermore, each cascaded transfer function and the transfer function of the converter are validated by step responses. All LCL filters, with an LC filter for comparison, are employed in the experimental setup. Owing to the applications, control characteristics and input current ripples are measured. In addition, the efficiencies of each different structure are determined. As a result of the analysis and measurements, the LCL trap filter gives better results in terms of efficiency (86%) and input current ripple (0.96 A peak). Moreover, the LCL with damping filter gives poorer control characteristics, but the maximum gain of the controller avoiding the instability of LCL with damping is 0.0855, which is higher than that of the others. Furthermore, it is shown that each LCL filter topology provides a 45% lower total inductor value compared to the LC filter.
Analysis of LCL Filter Topologies for DC-DC Isolated Cuk Converter at CCM Operation
(2022-01-01) Sehirli E.
In this study, the application and analysis of LCL filter topologies including an LCL, an LCL with damping, and an LCL trap filter used by a DC-DC isolated Ćuk converter operated at CCM are presented. The converter is designed for 50 W with 42 kHz switching frequency using a SiC MOSFET as a power switch. Although LCL filter topologies are commonly used with an inverter, their use in DC-DC converters has not been studied in detail. The main contribution of the paper is the application, design, and analysis of an LCL trap filter, which is not presented for a DC-DC converter in the literature, as an input filter of a DC-DC isolated Ćuk converter. For exact analysis of the effect of the filter, as a second main contribution of the paper, a state-space average mathematical model, small signal analysis of an isolated Ćuk converter for CCM operation, which was not presented before in the literature, is derived and its transfer function is obtained. In this paper, the practical design and transfer functions of LCL-based filter topologies are also presented. In order to analyze the effect of filter topologies by using linear methods including root locus and Bode graphs, the transfer function of the converter is cascaded with the transfer function of each filter separately, which is the third contribution of the paper because such analysis has not been presented in the literature. Furthermore, each cascaded transfer function and the transfer function of the converter are validated by step responses. All LCL filters, with an LC filter for comparison, are employed in the experimental setup. Owing to the applications, control characteristics and input current ripples are measured. In addition, the efficiencies of each different structure are determined. As a result of the analysis and measurements, the LCL trap filter gives better results in terms of efficiency (86%) and input current ripple (0.96 A peak). Moreover, the LCL with damping filter gives poorer control characteristics, but the maximum gain of the controller avoiding the instability of LCL with damping is 0.0855, which is higher than that of the others. Furthermore, it is shown that each LCL filter topology provides a 45% lower total inductor value compared to the LC filter.
BLDC Speed Control by Bidirectional Battery Charger with SEPIC MPPT
(2020-10-22) Sehirli E.; Cetinceviz Y.
In this paper speed control of brushless DC motor (BLDC) fed by lithium ion battery and photovoltaic energy using SEPIC MPPT with PO algorithm is realized. In order to charge and discharge the battery, bidirectional battery charger is used. Besides, control algorithm of the bidirectional battery charger is based on the condition of both state of charge (SOC) of battery and available PV power. Furthermore, the study is realized under the solar irradiation and ambient temperature changes by simulations. Thanks to the simulation, BLDC speed is shown under reference and torque changes. In addition, SOC of battery, PV power, battery power and load power are measured. Simulation results provides the desired response of this study.
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.
Design and application of high power factor SEPIC LED driver
(2017-02-10) Sehirli E.; Ustun O.
Design and implementation of high-power factor isolated Ćuk converter-based LED driver with SiC MOSFET
(2023-02-01) Sehirli E.; Üstün Ö.
In this paper, the application and design of a high-power factor isolated Ćuk converter-based LED driver are realized for up to 50 W power. For the power switch of the PFC isolated Ćuk converter, traditional Si and silicon carbide (SiC) MOSFETs, which are wide bandgap semiconductors, are used and compared. The application is conducted using a dsPIC30F4011 microcontroller including PI voltage control. A current sensor is added to limit maximum current. Moreover, PI control parameters are selected by genetic algorithm to avoid a complex mathematical procedure for controller design. The power LED model derived in this paper is used for the PI parameter selection process. In addition, the input side inductor of the converter is operated in discontinuous conduction mode, and the switching frequency of the power switch is 57 kHz. With the experimental setup, the total harmonic distortion (THD) of grid voltage and current, power LED voltage and current, switch voltage, and input side inductor current are shown for both the SiC and Si MOSFETs and compared. It is concluded from the application that the SiC-based driver gives better results than the Si-based driver on the basis of THD and efficiency. Further, both applications provide limits of IEC61000-3-2 C class standard.
Full Bridge DC-DC Converter Based Battery Charger with PFC CUK Converter Having Hysteresis Control
(2023-01-01) Karakas S.; Sehirli E.
HESS Based Hybrid Microgrid for Islanded and Grid Connected Operation
(American Institute of Physics Inc., 2023) Sehirli E.; Cetinceviz Y.; Usta O.
Hybrid micro grid system consisting of diesel generator, PV array, wind energy units using HESS including SMES, Li/Ion battery, SC is presented in this paper. Also, grid connection of DC bus is achieved by using NPC. Grid connected, islanded, mode operation is investigated for microgrid system. Although such operation is not presented in literature for SMES, this paper examines not only SMES but also Li/Ion, SC. Furthermore, MPPT including P O algorithm through Cuk converter is used for transmission of PV power to dc bus. Moreover, Li/Ion battery, SC and SMES have bidirectional converters separately providing bidirectional power flow. In addition, produced energy by wind, diesel generator units using synchronous generator is transferred to DC bus via buck converter connected to output of the rectifier. Besides, supervisory controller carries out the charge/discharge of battery, SC, power transmission of SMES and enables diesel generator, according to SOC of Li/Ion and SC, PV energy existence, wind speed, grid power. Supervisory controller also realizes load shedding of non-critical loads on the condition of non-existing enough power. Presented system is analyzed for islanded mode and grid connected operation through Matlab/Simulink. Owing to the simulation, SMES, SC, Li/Ion battery, wind, PV, diesel generator and grid power transmissions are presented. Seamless operation of proposed system is achieved, fast transients under few cycles are acquired regarding to operation mode. THD of phase voltages, currents provide the limit in standards which is not given in other papers in the literature in detail.
Input-output linearization control of single-phase buck-boost power factor corrector
(2012-12-01) Sehirli E.; Altinay M.
In this paper, simulations of single - phase power factor corrector (PFC) that has buck-boost circuit topology under input - output linearization nonlinear control with current and voltage control are realized. Buck-boost converter is connected to ac grid by single phase diode bridge rectifier and it works in boundary conduction mode (BCM). For switching of single switched buck-boost converter, compared saw tooth with dc control signal (PWM) technique has been utilized and switching frequency adjusted to 100 kHz. Simulations are carried out with Matlab/Simulink. By the simulations, the effect of PFC buck-boost rectifier on unity power factor, line current harmonic distortion, the sinusoidality of line current and dc - link voltage are presented. © 2012 IEEE.
Speed Control of BLDC by Using Neutrosophic Fuzzy Logic Controller
(2021-01-01) Hacat G.; Cetinceviz Y.; Sehirli E.
In this study, a control system based on neutrosophic logic is presented for field-oriented control (FOC) based speed control of brushless direct current motor (BLDC). Neutrosophic fuzzy logic controller (NFLC) was created with a fuzzy inference system in Matlab. In addition, to realize speed control of BLDC motor in Simulink environment, NFLC block diagram was created and compared with proportional integral (PI) control. The simulation results show that the BLDC motor speed is successfully and efficiently controlled by a neutrosophic fuzzy logic controller, giving better results than PI controller with respect to steady state error and settling time.
Speed control of PMSM Fed by bridgeless PFC isolated Cuk converter using LCL filter
(2021-07-06) Hukumen B.; Sehirli E.
In this paper, a LCL filtered power factor corrected (PFC) converter to feed permanent magnet synchronous machines (PMSM) having field-oriented control (FOC) method has been proposed. In order to compensate the total harmonic distortion (THD) and poor power factor (PF) problem while achieving the high efficiency and reducing the switching losses of the converter and the voltage source inverter (VSI), the proposed system has been designed as LCL filtered bridgeless single-stage PFC isolated cuk converter for low power applications. Value of the output inductor provides discontinuous conduction mode (DCM) operation for reducing the conduction losses on switches of the converter. On the other hand, source filter was designed as LCL type to ensure power quality improvement. Results of this paper through the simulation have demonstrated that the proposed system has a capability to drive low power applications within the boundaries of international power quality standards and speed of the PMSM was controlled as desired.
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.
Transient analysis with coupled field-circuit model and experimental assessment of a PMSG used in small-scale wind turbine for water heating purpose
(2019-12-01) Cetinceviz Y.; Sehirli E.; Uygun D.; Ocak C.; Demirel H.
This paper introduces the detailed coupled field-circuit analysis including performance characteristics of a 4-kW in-running rotor permanent magnet synchronous generator (PMSG) used in rural-type small-scale wind turbines for water heating purpose. The content of the work consists of design, analysis, optimization, production and testing processes and validation studies. An integrated 2D electromagnetic field and circuit model are used in the design and analysis processes. The electrical machine design involves complex and time-consuming processes. This model provides comprehensive information on machine behavior under different conditions and is an effective to demonstrate compliance with real load conditions prior to the manufacture. The goal of the optimization process is to find a design that offers cost, manufacturability and efficiency as well as generator output values. For this, a multiobjective optimization approach has been used. Typical design and simulation principles are applied to the designed PMSG, respectively, including calculation and evaluation of various output parameters for different simulated wind speed rates and varying load conditions. Furthermore, the analytical studies related to finite element methods and parametric approaches are presented in collaboration with experimental studies carried out for different load rates.