Browsing by Author "Boztepe, M."

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Placeholder
    Conference ObjectPublicationMetadata only
    Class E resonant converter design for LED drivers
    (IEEE, 2019-06) Zengin, Ö. Ö.; Boztepe, M.; Tekin, Ahmet; Electrical & Electronics Engineering; TEKİN, Ahmet
    The LED (Light Emitting Diode) lighting technology has been becoming widespread rapidly due to having advantages such as extremely long lifetime, compact structure and very low energy consumption. In the literature, various LED driver topologies are proposed for controlling the LED's current and voltage. However, most of them require a large capacitor and inductor values due to low switching frequency operation. On the other hand, high capacitance with low volume can be achieved by using the electrolytic type capacitors which limits the lifetime and reliability of LED driver. By the help of high switching frequency, converter size can be reduced significantly. In addition, the capacitor size decreases and therefore electrolytic capacitors can be eliminated. In this study, isolated Class E resonant topology operating at 1 MHz is analysed and designed for 48 V/60 W offline LED driver. The design methodology is presented and verified by PSIM simulation.
  • Placeholder
    Conference ObjectPublicationMetadata only
    An improved speed controller for PMSM drive with unbalanced load using load torque observer
    (IEEE, 2019) Yoldaş, Koray; Tekin, Ahmet; Boztepe, M.; Electrical & Electronics Engineering; TEKİN, Ahmet; Yoldaş, Koray
    In order to overcome disturbance effects as load torque variations in Permanent Magnet Synchronous Motor (PMSM) of washing machines, an improved controller with feed forward compensation is presented in this paper. A few load torque observer techniques have been studied and combined with several sensorless control techniques. The observed torque is used as feedforward in q-axis current PI controller to compensate the output of speed PI controller. Simulation and experimental results show that in an operating system with disturbances as washing machines, PI controller response time can be improved by adopting an accurate feedforward scheme.
  • Placeholder
    Conference ObjectPublicationMetadata only
    A robust voltage control method for universal EV battery charger LLC resonant converters
    (IEEE, 2019) Daş, Y.; Tekin, Ahmet; Boztepe, M.; Tarhan, C.; Electrical & Electronics Engineering; TEKİN, Ahmet
    In this study, a novel control method for LLC resonant converter with wide output voltage range and constant switching frequency is proposed targeting wide range of Electric Vehicle (EV) battery charger standards. In conventional LLC converter control topologies, in order to reach lower output voltage levels, switching frequency happens to move away from the resonance frequency, increasing in most of the cases. However, the switching losses due to switching devices start to become the main bottleneck at high switching frequency operation. Furthermore, high switching frequency operation may cause irreversible inrush current damage at the input terminals during the start-up with corresponding overshoot at the output voltage as well, risking the clients on this particular supply. The work presented in this paper proposes a robust and reliable control solution for these particular resonant converter drawbacks. Theoretical analysis for both conventional and proposed control methods are presented in detail. In order to show the effectiveness of the proposed technique, performance metrics of the both are compared experimentally on an LLC resonant converter specification having an output voltage range of 150-500 V with a maximum output power of 7.5 kW.