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Title: Multi-Physics Modeling and Design of Switched Reluctance Machines and Large Synchronous Generators
Committee:
Dr. Tom Habetler, ECE, Chair , Advisor
Dr. Maryam Saeedifard, ECE
Dr. Lukas Graber, ECE
Dr. Lijun He, GE Corporate Research
Dr. Rhett Mayor, ME
Abstract:
This dissertation focuses on developing multi-physics models for switched reluctance machines (SRMs) and the end regions of large synchronous generators (LSGs), so as to further exploit effective and efficient methods for the design optimization to improve their performances. In particular, for SRMs, a generalized and fast analytical model based on Maxwell’s equations and magnetic equivalent circuits (MECs) that predicts their electromagnetic (EM) behaviors is developed and validated by finite-element analyses (FEAs) and measured results; then, a hybrid thermal model combining 2-dimensional (2D) finite-difference (FD) formulations and thermal circuits is applied to estimate the temperature based on the loss distribution calculated by the EM model. Based on the multi-physics model, the methods of design of experiments (DoE) and evolutionary algorithms are adopted in the multi-objective optimization of SRMs. For the design of the end regions of LSGs, 3-dimensional (3D) EM and thermal models are constructed to estimate the magnetic field, loss density and temperature distributions in this region, which are verified by the agreement between the predicted and measured temperature values. To improve the computational efficiency, a harmonic quasi-3D FD formulation is developed that can provide acceptable solutions of the magnetic field and loss density distributions within a short period of time and is thus an appropriate tool for the initial design. In addition, parametric studies are performed to investigate the influences of different design parameters on the EM and thermal behaviors in the LSG end regions.
