Date of Award
Spring 2011
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Electrical and Computer Engineering
First Advisor
Demerdash, Nabeel A.O.
Second Advisor
Yaz, Edwin E.
Third Advisor
Schneider, Susan C.
Abstract
In this thesis, a fault mitigation method for delta-connected induction motor-drive systems under a two-phase open-delta faulty operating condition is analyzed and verified. More specifically, this fault mitigation technique can provide a set of almost balanced motor line currents, and significantly reduce torque ripples, even when the machine runs under the aforementioned two-phase open-delta faulty operating condition. This condition is analyzed using a Magnetic Equivalent Circuit (MEC) model. This model is developed for a delta-connected induction motor which is coupled to its drive system, including the fault mitigation controller. That is, the MEC model is linked to its associated PWM inverter to include the electronic switching effects. This global motor-inverter model was simulated in a Matlab-Simulink environment, under both healthy and faulty operating conditions, while the inverter is operated in both the open-loop scalar control and closed-loop vector control modes. The results obtained from the global model are compared in this thesis to the results obtained from the corresponding Time-Stepping Finite Element (TSFE) simulation and experimental motor-drive test data. A comparative analysis of the motor performance obtained from these results, under the two-phase open-delta faulty operating case, is presented in this work. The simulation and experimental data show that the delta-connected MEC model can provide reasonably accurate results. Thus, the validity and applicability of the fault mitigation technique is thereby verified.