Browsing by Author "Ahmed, Firdausa"

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  • Analytical Modeling of a Six-Phase Bearingless Synchronous Reluctance Machine Using Winding Function Theory
    (2023-12-29) Ahmed, Firdausa; Martin, Floran; Das, Nirangkush; Hinkkanen, Marko
     A4 Artikkeli konferenssijulkaisussa
    This paper presents a modeling framework for bearingless synchronous reluctance machines that are equipped with a six-phase stator winding. The six-phase combined winding can be used to produce both electromagnetic torque and radial forces. Vector-space decomposition (or generalized space-vector transformation) and winding function theory are applied in the presented framework. To exemplify these concepts, a conceptual machine is studied by means of analytical expressions and by finite-element analysis. The presented framework can be used to develop dynamic models for other multiphase bearingless machines as well. Resulting dynamic models can be used in time-domain simulations and in development of real-time control algorithms.
  • Damping Coefficient Characterization and Experiment of an Electromagnetic Damper for Shimmy Reduction
    (2024) She, Chenfei; Zhang, Ming; Hinkkanen, Marko; Ahmed, Firdausa; Shi, Jin; Liu, Xinyu
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This article investigates the damping coefficients of electromagnetic dampers (EMDs) employed for shimmy reduction in the nose landing gear of all-electric aircraft (AEA). Parasitic damping exists in the shimmy reduction subsystem, which causes the actual damping coefficients to differ significantly from those calculated only using the electromagnetic model in previous studies. This difference will directly lead to dimensional redundancy in the structural design of EMD. By establishing the power flow of the shimmy reduction channel in this study, the components of parasitic damping are identified, and the corresponding loss models are then developed. When the damping coefficient, which considers parasitic damping, is applied to the structural design of EMD, the dimensional parameters may be greatly reduced while still satisfying the technical requirements and achieving the goal of lightweight aircraft. Finally, the comparison of the analysis with the experimental data demonstrates good agreement.
  • Design methodology for a special single winding based bearingless switched reluctance motor
    (2017-06-01) Choudhury, Madhurjya Dev; Ahmed, Firdausa; Kumar, Gaurav; Kalita, Karuna; Tammi, Kari
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Bearingless switched reluctance motors (BSRMs) have both magnetic bearing as well as conventional motor characteristics which make them suitable for diverse industrial applications. This study proposes a design methodology for a BSRM in order to calculate the appropriate geometrical dimensions essential for realising a minimum levitation force at every orientation of rotor. It is based on the stator–rotor overlap angle and helps in reducing the complexities associated with the self-bearing operation of a switched reluctance motor (SRM). Different from a conventional SRM, the motor under study deploys a special single set parallel winding scheme for simultaneous production of torque as well as radial force. An analytical model incorporating this single set winding is developed for calculating the torque and the radial force. The proposed bearingless design is verified by developing a two-dimensional finite-element model of a 12/8 SRM in ANSYS Maxwell.