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An Application of PDM Technique for MPPT in Solar Powered Wireless Power Transfer Systems
(Ieee, 2021) Bal, Gungor; Oncu, Selim; Ozturk, Nihat; Unal, Kenan
In this study, a solar powered wireless power transmission system is simulated with MATLAB/Simulink. Wireless power transmission systems are the process of transferring electrical energy from the transmitting system to the receiving system without any physical connection. Pulse density modulation technique is used to generate control pulses for Maximum Power Point Tracking for wireless power transmission system. While the drive system is operated under soft switching conditions, it is able to follow the maximum power point in photovoltaic panels with high accuracy.
Comparison of regular and irregular 32 pulse density modulation patterns for induction heating
(Wiley, 2021) Karafil, Akif; Ozbay, Harun; Oncu, Selim
In this study, an induction heating (IH) application is carried out by transferring the maximum power extracted from photovoltaic (PV) panels to the stainless steel with the designed regular and irregular 32 pulse density modulation (PDM) controlled series resonant inverter. The main objective of this study is to analyse the changes in the system due to regular and irregular PDM patterns. Maximum power point tracker (MPPT) is used to control the output power at different solar irradiation values with varying PDM patterns. Regular and irregular PDM control methods are compared in terms of MPPT efficiency, cost, algorithm complexity, logic control structure and current/voltage stresses of the power switches. Zero current switching (ZCS) conditions are provided by using phase locked loop (PLL) technique at all power points of the PV system. The appropriate switching conditions are tracked continuously at resonant frequency, and therefore soft switching is realised. Perturb and observe (P&O) algorithm is used with the aim of tracking the maximum power in PV panels and high tracking efficiency is obtained with PDM-controlled P&O MPPT algorithm. ATMEL328P-AU microcontroller is used to control the inverter in the system.
CURRENT FED SELF OSCILLATING ELECTRONIC BALLAST DESIGN WITH PUSH PULL INVERTER
(Gazi Univ, Fac Engineering Architecture, 2009) Borekci, Selim; Oncu, Selim
Electronic ballasts are commonly used due to several advantages; among electronic ballasts, self oscillating electronic ballasts are not only simple and cheap but also have high efficiency because of zero voltage switching technique. Current and voltage fed topologies are commonly used in electronic ballasts. When both topologies are compared, current fed has better start up transient response. In this study, current fed push pull inverter circuit is designed for three 36W T8 fluorescent lamps. In the design, push pull transformer is wounded on a partition bobbin. Although it has the advantages of easy and reliable production for industrial automation and lowering the cost of the circuit, the coupling between the coils is considerably weak. Because of this, the weak coupling is taken into account in the design. The design has agreement with experimental and simulation results.
Design and Analysis of Single-Phase Grid-Tied Inverter With PDM MPPT-Controlled Converter
(Ieee-Inst Electrical Electronics Engineers Inc, 2020) Karafil, Akif; Ozbay, Harun; Oncu, Selim
In this article, a novel method is presented for maximum power point tracker (MPPT) system to increase efficiency. For this purpose, maximum power obtained from photovoltaic (PV) panels by pulse density modulation (PDM)-controlled high-frequency series-resonant converter was transferred to grid by a single-phase inverter. The resonant converter and the single-phase inverter circuits used in the system were analyzed, designed, simulated, and implemented. The designed series-resonant converter was operated at resonant frequency for different solar radiation conditions using the PDM control technique, and therefore the maximum power point was tracked. Soft switching was achieved by continuously tracking the resonant frequency. Simulated and experimental results were presented for 600 W prototype by operating the MPPT converter over 100 kHz. The MPPT efficiency was obtained as 99 & x0025; and above. The maximum power tracking of the PV panels was achieved using the perturb and observe (P & O) algorithm with PDM technique. The generated PV power was transferred to the single-phase grid by an LCL-filtered inverter. Proportional integral controller was preferred in the control of single-phase grid-tied inverter.
DESIGN AND IMPLEMENTATION OF A SELF OSCILLATING INDUCTION HEATER
(Gazi Univ, Fac Engineering Architecture, 2011) Bal, Gungor; Oncu, Selim; Borekci, Selim
Self oscillating circuits do not require more complicated control circuit. So they can provide low cost power control with very simple control circuit. Because of these advantages the self oscillating circuit topology is widely used in some power electronics applications such as inverters and electronic ballasts. In this study, an application of self oscillating control technique was achieved on an induction heater driven by D-class inverter. Transistors used as power switches are triggered in order by the feedback signal which follows load current. For the developed self oscillating induction heating system, results obtained from simulations and experiments are compared and then presented.
Design of Hybrid Controller for Automatic Voltage Regulator
(Gazi Univ, 2023) Bal, Gungor; Ozturk, Nihat; Oncu, Selim; Unal, Kenan
Synchronous generators are still the main machines in the production of electrical energy. Changing the excitation current and the rotation speed easily adjust their output voltage and frequency. Since synchronous generators are operated with the grid, the output voltage and frequency must be fixed. Various control systems are used in Automatic Voltage Regulators for adjusting the voltage. In this study, a hybrid controller structure proposed and it operates in MATLAB / Simulink program. The simulation results of the proposed AVR is compared with PID adjusted by Artificial Bee Colonies algorithm and Ziegler-Nichols based different controllers. The comparison was made on maximum overshoot, rise and settling time. According to the comparison made, it was seen that the proposed hybrid controller has better response than the other controllers in terms of maximum overshoot, rise and settling time.
Determination of Circuit Parameters in Domestic Induction Heaters by Analytical Solution Method
(Taylor & Francis Inc, 2024) Unal, Kenan; Oncu, Selim; Tuncer, Ugur; Bal, Gungor
Domestic induction heaters provide efficient, fast, and safe heating. Variable circuit parameters in domestic induction heaters show different characteristics depending on the type of parts used for heating and the area they cover on the heating coil. For this reason, resonant frequency, maximum inverter current, and quality factor parameters of the induction heaters also change. In this study, the tests of the domestic induction heater circuit with series resonant inverter were carried out with various of workpieces diameters. The resonant frequency and maximum inverter current parameters obtained from the experimental studies, curve fitting process was performed in the MATLAB and a function on related with heater parameters was derived. By using the obtained functions, the resonant frequency and maximum inverter current of the materials in the workpieces with intermediate diameters were calculated with high accuracy and compared experimentally. Analytical calculations and experimental results confirmed each other with an accuracy and it was shown that induction heater circuit parameters could also be calculated by analytical solution method.
Effects of a current transformer's magnetizing current on the driving voltage in self-oscillating converters
(Tubitak Scientific & Technological Research Council Turkey, 2014) Bal, Gungor; Oncu, Selim
Magnetizing inductance is one of the parameters that affect the phase and amplitude error of the output current of current transformers (CTs). In this study, the linear circuit model of a CT is developed to be used for driving purposes in power electronics applications. A simulation of the CT and its linear model is achieved. In the model circuit, the effect of the magnetizing inductance on the driving voltage can be examined. The equivalent circuit simulation results and the linear model simulation results along with the calculated results show agreement with each other. These results are compared with experimental results.
ELECTRONIC BALLAST POWER CONTROL WITH MAGNETICALLY CONTROLLED COIL
(Pamukkale Univ, 2008) Borekci, Selim; Oncu, Selim
Electronic ballasts have several advantages over magnetic ballasts such as providing higher efficacy, better illumination quality, longer lamp life and smaller size. In this study, magnetically controlled inductor controls the florescent lamp power by changing the ballast impedance and resonant frequency and the proposed topology is implemented on self-oscillating push pull electronic ballast. In the proposed ballast power control technique, zero voltage switching (ZVS) is accomplished. The topology is also simulated in order to compare the results. Both simulation and experimental results have good agreement.
External Rotor 6/8 Switched Reluctance Motor Design for E-Bike
(Ieee, 2021) Koyuncu, Samet; Tuncer, Ugur; Dalcali, Adem; Oncu, Selim
The interest in electric bicycles, which are personal transportation vehicles, is increasing due to the reasons such as being affordable, environmentally friendly and healthy. This article presents the design of an external rotor Switched Reluctance Motor (SRM) suitable for in-wheel use, with a 3-phase 6 stator pole number and 8 rotor pole number designed using the Finite Element Method (FEM). In the study, performance parameters such as output torque, magnetic flux density distribution, copper loss and core loss are presented The obtained results show that the proposed SRM structure is suitable for E-bike applications.
Full Bridge LLC Resonant Converter Design for Photovoltaic Applications
(Ieee, 2022) Kucuk, Tufan Volkan; Oncu, Selim
In this study, full bridge LLC resonant converter is simulated for photovoltaic (PV) system. The maximum power point tracking (MPPT) algorithm perturb and observe (P&O) is used to track the maximum power point (MPP) in the PV system at different irradiance values. P&O algorithm is adapted with phase shift modulation and made suitable for resonant converter. The proposed system is simulated with PSIM under three different irradiance values. It can be seen from the simulation results that MPPT and soft switching conditions have been successfully achieved in all three irradiance values.
A Golden Section Search Assisted Incremental Conductance MPPT Control for PV Fed Water Pump
(Int Journal Renewable Energy Research, 2022) Alrajoubi, Hamza; Oncu, Selim
One way to enhance the effectiveness of photovoltaic (PV) fed water pumping applications is to maximize the solar PV energy by using a suitable design with accurate and fast maximum power point tracking (MPPT). This paper presents a new hybrid MPPT method to improve speed response and efficiency. The method is designed to control a simple standalone PV water pumping system-based single-stage brushless DC (BLDC) motor. A DC-DC converter is eliminated to improve system efficiency and reduce cost. In addition, a two-mode hybrid MPPT algorithm that incorporates the golden-section search (GSS) technique-based MPPT algorithm with incremental conductance (INC) is implemented to enhance the global efficiency of the system. The GSS optimization method handles the initial stages to converge the global peak and helps to increase the convergence rate. In contrast, the INC MPPT method achieves sufficient accuracy with lower oscillation towards the MPPT during the final stages. The designed system is modelled, examined, and compared using traditional techniques in MATLAB/Simulink to evaluate the MPPT efficiency of the model. The results confirm that the proposed MPPT algorithm can successfully drive a 1150W BLDC motor with high tracking efficiency and reliability. The PV energy is transferred to the pump via a voltage source inverter (VSI) using the MPPT algorithm with a proportional-integral (PI) controller. As a result, the MPPT efficiency reached over 99%.
Hydrogen production system with fuzzy logic-controlled converter
(Tubitak Scientific & Technological Research Council Turkey, 2019) Nacar, Salih; Oncu, Selim
Electrolyte current must be controlled in the water electrolysis systems. For this purpose, the power converter for the cell stack of the electrolyzer used in industrial hydrogen production is realized. A series resonant converter, which is suitable for high input voltage and low output current applications, is used as power stage of the electrolyzer. The high-frequency transformer is used for the impedance matching. While the system is running, the electrical resistance of the electrolyzer changes continuously; thus, fuzzy logic controller (FLC) is used to control the output current of the power converter. In this study, a 700-W converter prototype is designed and controlled by the frequency modulation technique in the range of 290-360 kHz. The converter is tested for different output currents and it is observed that the power switches are turned on under soft switching conditions while FLC closely follows reference inputs.
Implementation of hydrogen generation system with resonant converter
(Gazi Univ, Fac Engineering Architecture, 2022) Nacar, Salih; Oncu, Selim
Purpose: To obtain the electrical load characteristic of alkaline electrolyzer that changes continuously with temperature for different operating conditions and to implement power control of the electrolyzer with the resonant converter to reduce the limitations of PWM switching at high switching frequencies. Theory and Methods: Experimental setup consisting of alkaline electrolyzer, the converter and the control circuit was established. The electrical load characteristic of the electrolyzer was obtained for different electrolyte temperatures, constant operating voltage and constant operating current. The closed-loop control of the system was carried out by proportional control. The amount of hydrogen produced for different electrolyte temperatures (40 degrees C and 50 degrees C) and nominal operating current (10 A) were calculated and approximately measured. The calculation and measurement results were presented comparatively in tables. Results and Conclusion: The current of electrolyzer must be controlled. The series resonant converter is suitable for applications with high input voltage and low output current, as the switching losses are reduced with decreasing the output current. In addition, the converter is simple in structure and easy to implement. For nominal operating current of electrolyzer, the efficiency and the switching frequency of the converter are 88% and 125 kHz, respectively. These efficiency and switching frequency values are higher than the efficiency and switching frequency value of insulated PWM converters realized for electrolysis applications. As a result of the calculations and measurements, it is observed that the energy, Faraday and cell efficiency of the electrolyzer are 80.05%, 74.47% and 59.61%, respectively. Moreover, these efficiency values increase with the increasing electrolyte temperature.
Implementation of the irregular pulse density modulation-controlled wireless power transfer system for constant current and constant voltage output
(Wiley, 2024) Unal, Kenan; Bal, Gungor; Oncu, Selim
In this paper, irregular 32 pulse density modulation (PDM)-controlled wireless power transfer (WPT) system is proposed for constant current (CC) and constant voltage (CV) outputs. The proposed WPT system has a load independent ZPA frequency characteristic with CC and CV outputs. Thus, soft switching conditions are achieved for both CC and CV outputs. An experimental prototype was prepared to validate the effectiveness of the proposed irregular 32 PDM-controlled WPT system. WPT coil design parameters are presented and analyzed with lateral and rotational misalignment conditions in ANSYS. The experiments were determined as 3 A for CC output and 200 V for CV output. The maximum efficiency of the proposed system is measured (95.34%) at aligned coils with 100 mm air gap. In addition, the efficiency results are presented and evaluated by performing experimental studies under both lateral and rotational misalignment conditions. In this paper, irregular pulse density modulation-ontrolled wireless power transfer system which can control 32 steps of power is proposed. The output power is controlled precisely, and the soft switching conditions are provided. The experimental results are presented for misalignment conditions.image
Induction heated metal hydride tube for hydrogen storage system
(Pamukkale Univ, 2022) Nacar, Salih; Oncu, Selim; Kayfeci, Muhammet
In this study, the metal tube is heated up to a certain temperature by induction heating method so that the hydrogen stored by metal hydride method in it can be discharged. The voltage fed series resonant inverter (SRI) is used in the power stage of the system and the power switches are turned on under soft-switching conditions. The closed loop controlled 300 W SRI is designed to set the temperature of the tube to the reference temperature of 250 degrees C. The power control of SRI is realized by frequency control. The temperature of the tube is controlled by hysteresis on-off control due to its simple structure and easy applicability. 16-bit DSPIC33FJ16GS502 is used in the control of the system.
Investigation of the effects of different operating regions of ZVS LLC resonant converter on the converter performance
(Gazi Univ, 2024) Nacar, Salih; Oncu, Selim
FM controlled ZVS LLC resonant converter operates with low switching losses at high switching frequencies for a wide input voltage range. To obtain a constant output voltage against varying input voltage and load, the DC voltage gain of the converter, hence its operating intervals, needs to be changed. In different operating intervals, many operating parameters change besides the DC voltage gain of the converter. In this study, ZVS operating intervals of the converter are compared in terms of efficiency, switch stresses, and soft switching for constant output voltage against varying input voltage and load. The prototype circuit of the converter with the input voltage range of 80-120 V, nominal input voltage of 100 V, and output voltage of 8 V is established. The measurement results obtained from the prototype circuit for much different input voltage and load values are presented comparatively. The effect of different ZVS operating intervals on the operating parameters of the converter is revealed in many ways. Moreover, it is observed that the operating performance of the converter around series resonance frequency is better than the operating frequencies far from this frequency value.
Irregular 64 PDM Controlled Wireless Power Transfer for Pecise Power Control
(Ieee, 2023) Unal, Kenan; Bal, Gungor; Oncu, Selim
The power control techniques used in wireless charging systems can be divided into two classes: variable frequency and fixed frequency. In variable frequency power control, the efficiency of the charging system decreases when it is operated outside the zero-phase angle (ZPA). The efficiency of the wireless charging system increases when fixed frequency charging systems are operated even at ZPA frequency and under soft switching conditions. In this paper, an irregular 64-PDM controlled wireless charging system is proposed. The proposed 64-PDM controlled wireless charging system is implemented in a class-D inverter in a MATLAB/Simulink environment and the results are presented. As a result of the simulations, the efficiency of the wireless charging system operating under soft switching conditions at ZPA frequency is presented.
Laboratory setup for teaching resonant converters and induction heating
(Elsevier - Division Reed Elsevier India Pvt Ltd, 2022) Oncu, Selim; Unal, Kenan; Tuncer, Ugur
In this study, a laboratory prototype is implemented for electrical and electronics engineering students to have theoretical and practical knowledge about the resonant power conversion and induction heating systems. For this purpose, a safe low voltage induction heater laboratory prototype with full bridge series resonant inverter is set up and tested with different workpieces. Experimental studies for different load types are achieved and quality factor, resonant frequency, maximum inverter current, inductance and resistance values are investigated. The unique value of this study is that students will have knowledge about second order circuits, resonant converters and learn what conditions affect the circuit parameters of an induction heater. The properties of induction heaters will also be learned on this circuit. CO 2021 Karabuk University. Publishing services by Elsevier B.V.
Modeling and Simulation of External Rotor 6/8 Switched Reluctance Motor for E-Bike
(Ieee, 2022) Oncu, Selim; Tuncer, Ugur; Koyuncu, Samet
Switched reluctance motors (SRMs) have become strong candidates for light electric vehicles due to their many advantages. SRMs have a non-linear flux characteristic because they have doubly salient structure. Therefore, the modeling of this motor is quite complex. In this study, a dynamic model of 6/8 external rotor SRM (ER-SRM) is carried out in MATLAB/Simulink. Magnetic characteristics of ER-SRM are obtained by finite element method (FEM). The speed control is examined for the variable speed and load values of the SRM.

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