Engineering Commons^™

Computationally Efficient Optimization Of A Five-Phase Flux-Switching Pm Machine Under Different Operating Conditions, Hao Chen, Xiangdong Liu, Nabeel Demerdash, Ayman M. El-Refaie, Zhen Chen, Jiangbiao He

Electrical and Computer Engineering Faculty Research and Publications

This paper investigates the comparative design optimizations of a five-phase outer-rotor flux-switching permanent magnet (FSPM) machine for in-wheel traction applications. To improve the comprehensive performance of the motor, two kinds of large-scale design optimizations under different operating conditions are performed and compared, including the traditional optimization performed at the rated operating point and the optimization targeting the whole driving cycles. Three driving cycles are taken into account, namely, the urban dynamometer driving schedule (UDDS), the highway fuel economy driving schedule (HWFET), and the combined UDDS/HWFET, representing the city, highway, and combined city/highway driving, respectively. Meanwhile, the computationally efficient finite-element analysis …

Fault-Tolerant Technique For Δ-Connected Ac-Motor Drives, Ahmed Mohamed Sayed Ahmed, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A fault-tolerant technique for motor-drive systems is introduced in this paper. The technique is merely presented for ac motors with Δ-connected circuits in their stator windings. In this technique, the faulty phase is isolated by solid-state switches after the occurrence of a failure in one of the stator phases. Then, the fault-tolerant technique manages current-flow in the remaining healthy phases. This technique is to significantly mitigate torque pulsations, which are caused by an open-Δ configuration in the stator windings. The performance of the fault-tolerant technique was experimentally verified using a 5-hp 460-V induction motor-drive system and the results are presented …

A Reconfigurable Motor For Experimental Emulation Of Stator Winding Inter-Turn And Broken Bar Faults In Polyphase Induction Machines (Journal Article), Chia-Chou Yeh, Gennadi Y. Sizov, Ahmed Sayed-Ahmed, Nabeel Demerdash, Richard J. Povinelli, Edwin E. Yaz, Dan M. Ionel

Electrical and Computer Engineering Faculty Research and Publications

The benefits and drawbacks of a 5-hp reconfigurable induction motor, which was designed for experimental emulation of stator winding interturn and broken rotor bar faults, are presented in this paper. It was perceived that this motor had the potential of quick and easy reconfiguration to produce the desired stator and rotor faults in a variety of different fault combinations. Hence, this motor was anticipated to make a useful test bed for evaluation of the efficacy of existing and new motor fault diagnostics techniques and not the study of insulation failure mechanisms. Accordingly, it was anticipated that this reconfigurable motor would …

Diagnosis Of Inter-Turn Short Circuit For A Polyphase Induction Motor In Closed-Loop Vector-Controlled Drives, Ahmed Sayed-Ahmed, Gennadi Y. Sizov, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

The main objective of this paper is to develop and experimentally verify a new technique to detect an inter-turn short circuit in one phase of a stator winding of an induction motor energized from a vector-controlled drive. This is in order to overcome the fault masking difficulties associated with the concept of depending on the actual magnetic field pendulous oscillation between the conventional voltage and current space vectors with respect to a reference that is unaltered by the compensation action of the drive. This technique is based on the flux pendulous oscillation phenomenon. This flux pendulous oscillation is also described …

Inter-Turn Fault Diagnosis In Induction Motors Using The Pendulous Oscillation Phenomenon, Behrooz Mirafzal, Richard J. Povinelli, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A robust interturn fault diagnostic approach based on the concept of magnetic field pendulous oscillation, which occurs in induction motors under faulty conditions, is introduced in this paper. This approach enables one to distinguish and classify an unbalanced voltage power supply and machine manufacturing/construction imperfections from an interturn fault. The experimental results for the two case studies of a set of 5-hp and 2-hp induction motors verify the validity of the proposed approach. Moreover, it can be concluded from the experimental results that if the circulating current level in the shorted loop increases beyond the phase current level, an interturn …

Soft-Started Induction Motor Modeling And Heating Issues For Different Starting Profiles Using A Flux Linkage Abc Frame Of Reference, M. G. Solveson, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

In order to mitigate the adverse effects of starting torque transients and high inrush currents in induction motors, a popular method is to use electronically controlled soft-starting voltages utilizing series-connected silicon-controlled rectifiers (SCRs). Investigation of semioptimum soft-starting voltage profiles was implemented using a flux linkage ABC frame of reference model of a soft-started three-phase induction motor. A state-space model of the soft-starter thyristor switching sequence for the motor and load was developed and implemented in a time-domain simulation to examine winding heating and shaft stress issues for different starting profiles. Simulation results of line starts and soft starts were compared …

On Innovative Methods Of Induction Motor Interturn And Broken-Bar Fault Diagnostics, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A fault indicator, the so-called swing angle, for broken-bar and interturn faults is investigated in this paper. This fault indicator is based on the rotating magnetic-field pendulous-oscillation concept in faulty squirrel-cage induction motors. Using the "swing-angle indicator," it will be demonstrated here that an interturn fault can be detected even in the presence of machine manufacturing imperfections. Meanwhile, a broken-bar fault can be detected under both direct-line and PWM excitations, even under the more difficult condition of partial-load levels. These two conditions of partial load and motor manufacturing imperfections, which are considered as difficult situations for fault detection, are investigated …

Effects Of Load Magnitude On Diagnosing Broken Bar Faults In Induction Motors Using The Pendulous Oscillation Of The Rotor Magnetic Field Orientation, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

The effects of load level on the ability to diagnose broken bar faults in squirrel-cage induction motors are studied in this paper. The pendulous oscillation of the rotor magnetic field orientation is implemented as a fault signature for rotor fault diagnostic purposes at steady-state operations. Moreover, the effects of load level on the low-side band component of the stator current spectrum, and associated diagnostic difficulties in this approach particularly in the presence of motor operation from pulsewidth-modulation drives, are reported as well. These investigations were performed through testing 2-hp and 5-hp induction motors over a wide range of load levels …

Condition Monitoring Of Squirrel-Cage Induction Motors Fed By Pwm-Based Drives Using A Parameter Estimation Approach, Behrooz Mirafzal, F. Fateh, Chia-Chou Yeh, Richard J. Povinelli, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

Abstract:

A rotor condition monitoring technique is presented in this paper based on a parameter estimation approach. In this technique, the stator currents, voltages and motor speed are used as the input signals, where the outputs will be the rotor's inductance, resistance and consequently rotor time constant. This approach is verified by simulation of two different induction motor cases. These simulations are buttressed by experimental data obtained for a 2-hp induction motor in the case of healthy as well as one, three and five rotor bar breakages. In these tests, the induction motor was energized from a PWM-based drive, in …

Induction Machine Broken-Bar Fault Diagnosis Using The Rotor Magnetic Field Space-Vector Orientation, Behrooz Mirafzal, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A new technique based on rotor magnetic field space vector orientation is presented to diagnose broken-bar faults in induction machines operating at steady state. In this technique, stator currents and voltages are used as inputs to compute and subsequently observe the rotor magnetic field orientation, which has a more significant "swing-like" pendulous oscillation in case of broken-bar faults than in healthy operation. It will be shown here that the range of this "pendulous oscillation" is a function of the number of broken bars. Also in this technique, it was found that an inter-turn shorted stator-winding fault, which exhibits similar pendulous …

Diagnostics Of Bar And End-Ring Connector Breakage Faults In Polyphase Induction Motors Through A Novel Dual Track Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Modeling, Richard J. Povinelli, John F. Bangura, Nabeel Demerdash, Ronald H. Brown

Electrical and Computer Engineering Faculty Research and Publications

This paper develops the fundamental foundations of a technique for detection of faults in induction motors that is not based on the traditional Fourier transform frequency domain approach. The technique can extensively and economically characterize and predict faults from the induction machine adjustable speed drive design data. This is done through the development of dual-track proof-of-principle studies of fault simulation and identification. These studies are performed using our proven Time Stepping Coupled Finite Element-State Space method to generate fault case data. Then, the fault cases are classified by their inherent characteristics, so-called “signatures” or “fingerprints.” These fault signatures are extracted …