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    Implementation of a flywheel energy storage system for space applications
    (Tubitak Scientific & Technological Research Council Turkey, 2017) Celikel, Resat; Ozdemir, Mehmet; Aydogmus, Omur
    A satellite power system requires solar panels to provide energy and orientation. There are two regions in the orbital path of the satellite: the dark and bright region. The energy is provided by solar panels in the bright region and by flywheel energy storage system (FESS) in the dark region. Brushless DC (BLDC) motors are widely used in the FESS due to their low weight, high power density, high efficiency, high reliability, and high speed. Some mechanical resonances may occur due to physical features of the mechanical parts. Therefore, the current of the BLDC is dramatically increased because of the mechanical resonance. In this work, a current reference method was used to protect the power systems of the satellite from the current spikes of the solar power system. The parameters of the PI controller were calculated by using genetic algorithms. A FESS was designed and experimentally performed for high speed operation at about 20 krpm in the vacuumed environment.
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    Öğe
    Reducing Mechanical Resonance Time of A Flywheel Energy Storage System by Using A Current Control Algorithm for Satellites
    (Gazi Univ, 2017) Celikel, Resat; Ozdemir, Mehmet; Aydogmus, Omur
    The orbital period of a satellite is completed with two regions as defined bright and dark. The energy must be stored in the bright region of the orbital path. The flywheel energy stored systems are used to provide energy in the dark region. However, the flywheel mechanical systems have mechanical resonance problems which decrease the system performance. The brushless dc motor operates as a motor with undesirable high-current when exposed the mechanical resonance. In this paper, a current reference method is proposed to decrease the current spike and reduce the time period of the mechanical resonance. The performance of the proposed method has been demonstrated by using simulation results and experimental results.
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    Öğe
    A torque ripple minimization method for brushless DC motor in high speed applications using buck boost topology
    (Academic Publication Council, 2019) Celikel, Resat; Aydogmus, Omur
    The torque ripple occurs due to commutation time of phase currents in the brushless direct current (BLDC) motors. In this paper, an effective method is developed to reduce torque ripple with wide speed control range for the high speed BLDC motor applications. A boost-buck converter topology has been used in this work. The boost-buck converter is placed between DC power supply and DC-link of the inverter. The DC-link voltage is adjusted depending on motor speed. Pulse Width Modulation (PWM) is used in order to control the phase currents of high speed BLDC motor. The PWM duty cycle is adjusted to reduce the ripple of the phase currents at the commutation time. The current control of the high speed BLDC motor is analyzed for three different methods. Firstly, the conventional method with constant DC-link voltage has been performed. Secondly, a variable DC-link voltage by using a boost-buck DC-DC converter has been performed. Thirdly, both variable DC-link voltage via boost-buck converter and current control method by using PWM have been performed. The waveforms of current and torque are given for different speed conditions in the steady state and during commutation. The conventional current controls and proposed current control strategies are presented by comparing performance.