Pragasen Pillay

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The selective harmonic elimination PWM (SHEPWM) method is systematically applied for the first time to multilevel series-connected voltage source PWM inverters. The method is implemented based on optimization techniques. The optimization starting point is obtained using a phase-shift harmonic suppression approach. Another less computationally demanding(More)
Previous work on condition monitoring of induction machines has focused on steady-state speed operation. Here, a new concept is introduced based on an analysis of transient machine currents. The technique centers around the extraction and removal of the fundamental component of the current and analyzing the residual current using wavelets. Test results of(More)
A new algorithm is introduced for motor current signature analysis of induction machines operating during transients. The algorithm is able to extract the amplitude, phase and frequency of a single sinusoid embedded in a nonstationary waveform. The algorithm is applied to the detection of broken rotor bars in induction machines during startup transients.(More)
This paper applies genetic algorithms to the problem of induction motor parameter determination. Generally available manufacturers’ published data like starting torque, breakdown torque, full-load torque, full-load power factor, etc., are used to determine the motor parameters for subsequent use in studying machine transients. Results from several versions(More)
For electrical machine designers, core loss data are usually provided in the form of tables or curves of total loss versus flux density or frequency. These can be used to extract the loss coefficients of the core loss formulas. In this paper, three currently available formulas are discussed and compared with the loss data supplied by lamination steel(More)
This paper examines the proper application of induction machines when supplied by unbalanced voltages in the presence of over-and undervoltages. Differences in the definition of voltage unbalance are also examined. The approach adopted is to use NEMA derating for unbalanced voltages as a basis to include the effects of undervoltages and overvoltages through(More)
Conventional Property Optimization Techniques Applicability Applicable toil specific problem domain. Number of points being simultaneSingle point ously searched Transition from current point to the Deterministic next Prerequisites Auxiliary knowledge such as gradient vectors. Provided bv the user Initial euess Abstract-This paper demonstrates the(More)
This paper discusses the modeling of a solid oxide fuel cell using both lumped and distributed modeling approaches. In particular, the focus of this paper is on the development of a computationally efficient lumped-parameter model for real-time emulation and control. The performance of this model is compared with a detailed distributed model and(More)
In situ machine efficiency estimation techniques are increasing in importance due to pressures to improve performance and for demand-side management. Numerous techniques have been proposed to estimate the efficiency of an induction motor in situ . Only a few are actually practical considering the level of intrusion and the accuracy. Besides, very little has(More)
The negative effects of a particular unbalanced voltage on the performance of an induction motor are studied in this paper. The paper suggests that the available definitions of unbalanced voltages are not comprehensive and complete. Therefore, the results of these analyses on motor performance are not very reliable. To prove this claim, a three-phase 25-hp(More)