Browsing by Author "Koc, Yavuz"

Now showing 1 - 3 of 3

Analysis and Design of Stacked Coupled Inductor Quadratic Boost Converter With a Lossless Snubber Cell
(Wiley, 2024) Koc, Yavuz; Birbir, Yasar; Ozel, Erdogan
This paper introduces the stacked coupled inductor quadratic boost converter with an inductorless, passive lossless snubber cell suited for high step-up applications with various microgrids. Some design constraints can be selected from the voltage gain techniques of the high step-up converters to obtain the solution of improvement performance of converter. The proposed converter utilizes quadratic boost converter and coupled inductor to attain high voltage gain beyond the voltage multiplier/lift cells. In this proposed converter, the use of a stacked coupled inductor type introduces the leakage inductor to snubber cell as an inductor without using an extra inductor in proposed snubber cell. Thus, a regenerative snubber cell is used to achieve a high system efficiency. Compared with earlier counterparts, the solution of attaining a high voltage gain in the proposed converter and passive lossless snubber cell leads to an increase in the converter's performance, reliability, and robustness. The theoretical expectations are supported by simulations and verified by experimental results obtained by implementing a 300-V, 120-W prototype.
Experimental Verification of an Improved Soft-Switching Cascade Boost Converter
(Elsevier Science Sa, 2017) Genc, Naci; Koc, Yavuz
A soft switching cascade DC-DC boost converter is proposed in this paper. The proposed cascade single switch converter has a higher step-up voltage gain and a wider turn-of period compared to classical boost converters, which tend to have a problem of narrow turn-of periods at higher output voltages. To reduce the switching losses, an auxiliary circuit was also added to the converter. It has a simple structure with only one main switch, one auxiliary switch and the minimum number of diodes. The proposed soft switching method enables the main switch to turn on at zero-voltage-transition (ZVT) and turn off at zero-voltage-switching (ZVS). Furthermore, the auxiliary switch and diodes are soft-switched thanks to this method. All semiconductor components operate under soft-switching, safe from any additional voltage and current stresses. The study presents the design considerations for the proposed converter, along with principle operations of the topology in a single switching period. Finally, experimental results, which were obtained on a laboratory prototype rated at300 W, are also presented in the paper. The results show that the proposed cascade boost converter can be operated successfully in soft-switching operation for a variety of input voltages and a relatively wider load range, even at higher voltage outputs. (C) 2017 Elsevier B.V. All rights reserved.
Non-Isolated High Step-Up Dc/Dc Converters - an Overview
(Elsevier, 2022) Koc, Yavuz; Birbir, Yasar; Bodur, Haci
High step-up, high efficiency, low cost DC/DC converters have operated as an interface to make use of the renewable energy system generated power. In order to obtain desired output voltage, the DC/AC voltage conversion to AC mains voltage is an important consideration mainly achieved through inverters. Taking into acoount the performance of the non-isolated high step-up DC/DC converters for the renewable energy systems, the substantial amount of topologies studied in past years are the non-isolated high step-up DC/DC converters. Based on proposed and generalized configurations, the non-isolated high step-up DC/DC converters are classified into several categories and reviewed in this paper. So, to clarify the distinguishing solutions, the key features; topological variations, merits and demerits of these converters are discussed and compared. This review work aims to give a well-informed and a well-detailed general framework about these converters and facilitates to derive the new well topologies in the future. (C) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.