Committee:

Dr. Habetler, Advisor

Dr. Graber, Chair

Dr. Harley

Abstract:

The objective of the proposed research is to develop methods for the
multi-objective design, optimization, and condition monitoring of electric
machines, so as to generate the optimal designs and improve machine
robustness for traction applications. In particular, the selected
high-performance electric machines are the switched reluctance machines (SRM)
with simple and robust structure, and the interior permanent magnet (IPM)
machines with high torque density and efficiency. For SRMs, an active current
profiling technique integrated multi-objective analytical design and
optimization is proposed to generate the optimal designs in terms of the
multiple performance indices, which is proved to be accurate and time-saving,
especially for a large search space with multiple prime design variables. The
proposed scheme offers machine designers accurate, handy and convenient
initial designs, which can be further verified or fine-tuned by FEA. To
monitor the demagnetization properties of the closed-loop direct torque
controlled (DTC) IPMSMs, a nonintrusive high-frequency flux injection based
PM temperature estimation method is proposed by analyzing the PM electrical
high-frequency resistance, which is a byproduct of the eddy current loss
induced by the applied high-frequency magnetic field. The developed IPM
machine model results in practical ways to excite a proper amount of
high-frequency current into the stator windings, which leads to a simple,
accurate, and non-intrusive permanent magnet thermal monitoring scheme for
DTC-controlled IPM machines.
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