Browsing by Author "Üstün Ö."

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Comparison of single phase buck-boost and sepic LED driver
(2017-01-01) Şehirli E.; Altınay M.; Üstün Ö.; Çakır B.
This paper presents the comparison of LED driver topologies that include buck-boost and SEPIC converters. Both topologies are connected to grid over single phase diode rectifier and designed for 8W power. Furthermore, buck-boost and SEPIC converters operate with 63 kHz switching frequency and inductors of SEPIC are wounded as coupled. By means of the implementations, power factor (PF) and total harmonic distortion (THD) of current and voltage, power LED voltage and current are shown for both topologies. Comparison is also made between IEC61000-3-2 standard, buck-boost and SEPIC converters. Besides, electrical circuit model of power LED is derived by using its current-voltage characteristic.
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.