WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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Author: search.filters.author.Tekgun, DidemPublisher: search.filters.publisher.IEEE

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Now showing 1 - 7 of 7
  • Conference Object
    Structural Integrity Analysis of a Two-Pole Synchronous Reluctance Machine With Non-Circular Shaft
    (IEEE, 2023-06-14) Tekgun, Didem; Tekgun, Burak; Alan, Irfan
    This paper investigates the structural strength of a 6-inch diameter, two-pole, 4 kW line start synchronous reluctance machine (LS-SynRM) designed with a new non-circular shaft structure that serves as a pump motor. Flux paths on the rotor are widened while narrowing down the shaft of the motor on the q- axis to improve the motor efficiency. By using this method, a wider path is created for the flux in the d-axis. As a result, the inductance in the d-axis, the ratio of inductance between the d-axis and q-axis (referred to as saliency ratio), and the difference in inductance between the d-axis and q-axis are all amplified. To evaluate the structural strength of the machine, a series of analyses are conducted, including modal, harmonic, and static examination on the rotor using ANSYS Structural. The findings indicate that to prevent redundant deformations and undesirable vibrations because of resonance, the maximum safe limit for shaft size reduction is determined as 8 mm.
  • Conference Object
    Power Factor Improvement of a Permanent-Magnet Vernier Machine with Harmonic Injected Excitation Currents
    (IEEE, 2025-06-11) Karatepe, Hasan Can; Tekgun, Didem
    Permanent-magnet vernier machines (PMVM) are recognized for their high torque density but low power factor (PF) due to high inductive reactance. This paper presents a method for improving the PF of a PMVM by injecting additional harmonics into the excitation currents. This injection is done through the motor drive, unlike many proposed methods for enhancing PF, thus eliminating any modifications needed on the machine's geometric design. In this paper, different sets of harmonic injected currents are fed to a 14-rotor pole 12-slot PMVM with short-pitched coils on Finite Element Analysis (FEA) to demonstrate the effects of individual and combined harmonic currents. Corresponding performance characteristics of each simulation case, such as PF and torque density, are investigated. Simulation results indicate that PF can be improved by the proposed method of harmonic current injection. A comparison with a similarly sized permanent-magnet synchronous machine (PMSM) is made to demonstrate that the proposed method can be an alternative to widely used PMSMs.
  • Conference Object
    Citation - WoS: 5
    Citation - Scopus: 5
    Investigation of the Effects of Multi-Layer Winding Structures in Two Pole Synchronous Reluctance Machines
    (IEEE, 2021-10-05) Tekgun, Didem; Cosdu, Muhammed Muhsin; Tekgun, Burak; Alan, Irfan; Muhsin Cosdu, Muhammed
    In this paper, a comparative study is performed between single, various double, and triple-layer winding structures to investigate the effects of the winding MMF harmonics and end winding length on the two-pole synchronous reluctance machines (SynRM). A two-step design approach is used including winding and geometry optimization using multi-objective differential evolution (MODE) algorithm. In the first stage, a Pareto front is obtained which determines the number of turns for each coil group for all winding configurations. Later in the second stage, three results are selected from the first stage to perform a geometric optimization to distinguish the effects of the THD and end winding length on the synchronous performance of a 4 kW two-pole SynRM. For the same average torque output, efficiency, mass, and the torque ripple of the selected designs are investigated and compared. Based on the analysis, it is concluded that rather than focusing on shortening the end winding length, reducing the MMF harmonics have a more positive effect on the machine performance as reduced harmonics resulted in efficiency improvement up to 2 points and torque ripple is reduced up to 8 points while having similar motor mass.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 2
    Influence of Eccentricity Faults on IPM Motor Equivalent Circuit Characteristics
    (IEEE, 2025-06-11) Tekgun, Didem
    Interior Permanent Magnet (IPM) machines are preferred in various modern applications due to their high efficiency, compact design, and reliability. They are especially favored in electric vehicle (EV) powertrains but also play a key role in hybrid vehicles, electric motorcycles, industrial automation systems, robotics, and home appliances such as air conditioners and washing machines. Eccentricity is a critical and challenging issue since it causes an unbalanced airgap magnetic flux and forces, eventually resulting in vibration, noise, and a higher likelihood of motor malfunction over time. This study investigates the effects of eccentricity faults on the motor's magnetic flux density and corresponding equivalent circuit parameters through Finite Element Analysis (FEA). The results show that the two types of eccentricity, static and dynamic, produce noticeable variations in the airgap magnetic flux as well as in key equivalent circuit parameters. Specific equivalent circuit parameters are particularly sensitive to different eccentricity faults, making them key indicators for early fault detection.
  • Conference Object
    Citation - Scopus: 2
    Effect of the Stator Slot Indents on Fluid Damping Loss in Submersible Pump Applications
    (IEEE, 2022-06-14) Tekgun, Didem; Cosdu, Muhammed Muhsin; Tekgun, Burak; Alan, Irfan
    In this study, the effect of fluid damping on the performance of a 2-pole, 4-kW line start synchronous reluctance machine (LS-SynRM) with different slot opening structures for submersible water pump applications is investigated. Since the submersible pump motors run inside a fluid-filled environment and the fluid viscosity and density differ from the air, it causes an increased damping effect comparing air-filled machines. Hence, a non-negligible damping loss occurs. In this study, the damping effects of the fluids in a 24 slot LS-SynRM for various stator slot indentations are investigated with computational fluid dynamics (CFD) finite element analysis (FEA) to highlight the importance of the fluid damping loss in flooded machines. Results show that the damping loss can go as high as 10% of the motor output power when the stator surface has indentations, and this loss can be cut down to 3.5 % when the surface indentations are eliminated with custom no-slotting wedge structures.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 1
    Design and Optimization of an Outer Rotor Spoke Type PMSM With Improved Saliency for a Lightweight Racing Vehicle
    (IEEE, 2024-11-12) Karatepe, Hasan Can; Tekgun, Burak; Tekun, Diclem; Tekgun, Didem
    This paper presents the design and optimization of an outer rotor spoke-type permanent magnet synchronous motor, aimed at achieving high torque density. The improvement is accomplished by enhancing the saliency through a center shift of the rotor arc, while simultaneously minimizing cogging torque and torque ripple. The proposed design is optimized for an electro-mobile that will participate in TEKNOFEST's "Efficiency Challenge". A vehicle dynamics simulation with the parameters of the designed vehicle was done under the "New European Driving Cycle" (NEDC) to determine the required torque and speed values using MATLAB's "Virtual Vehicle Composer" application. The multi-objective differential evolution (MODE) algorithm was chosen for optimization and further altered for maximum torque per ampere (MTPA) angle sweep, since each optimization individual would have a different MTPA angle. The optimization was conducted with 40 generations and 522 individual designs. An optimal solution from the Pareto-Front was selected and its performance was investigated using the 2D finite element analysis (FEA).
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    A Modular Three-Phase Buck-Boost Motor Drive Topology
    (IEEE, 2020-10-05) Tekgun, Didem; Tekgun, Burak; Alan, Irfan
    The voltage-source inverter (VSI) is a fundamental power electronic device to drive three-phase electrical machines with high performance. In this paper, a modular three-phase DC/Rectified AC/AC (DC/RAC/AC) inverter supplying a permanent-magnet synchronous machine (PMSM) is proposed. In this topology, the three-phase VSI is composed of three single-phase modules connected in parallel. Each single-phase inverter module consists of a non-inverting bidirectional buck-boost DC/DC converter and a cascaded H-bridge inverter. Here, the DC/DC converter generates rectified AC waveforms and the H-bridge inverter alternates these signals to create the intended AC voltage waveform. Therefore, the bulk DC Bus capacitor and boost converter inductor, which exist in a typical battery-powered voltage boosting topology can be eliminated which results in a smaller size and reduced cost. In addition, the switching losses only occur in the DC/DC converter unit and the H-bridge inverter switching losses are negligible due to the zero-voltage switching while in a conventional structure, high-frequency switching occurs both in the DC/DC converter and the six-switch inverter causing reduced overall system efficiency. The proposed inverter is controlled with a well-known field-oriented control (FOC). This paper presents the operating principle, design, and control structure of the proposed three-phase inverter. The functionality of the three-phase inverter is verified through PowerSim simulations. The proposed motor drive system is compared to the conventional one while driving a 4 kW PMSM with FOC and the whole system efficiency difference map is generated. The biggest difference is recorded as 3.8 points favoring the proposed system.