This paper presents an improved method of estimating flux angle, rotor position, and velocity by tracking the position of spatial saliencies in an ac machine. Specifically, a machine model is presented which accurately models the behavior of ac machines with multiple spatial harmonic saliencies. The effects of multiple spatial harmonic saliencies on the estimation of flux angle, position, and v...

Doubly fed wound rotor induction machine with vector control is very attractive to the high performance, variable speed drive and generating applications[ 1-31. In variable speed drive application, the so-called slip power recovering scheme is a common practice where the power due to the rotor slip belowlabove synchronous speed is recovered to/supplied from the power source, resulting a high ef...

Stray load loss refers generally to the sources of induction machine loss not accounted for by typical calculations of primary or secondary copper loss, no load core loss, or friction and windage loss. Harmonic rotor bar currents from the non-sinusoidal distribution of the slotted stator winding contribute significant stray load loss. Rotor bars, especially on cast rotors for machines under fif...

different methods for detecting broken bars in induction motors can be found in literature. many of these methods are based on evaluating special frequency magnitudes in machine signals spectrums. current, power, flux, etc are among these signals. frequencies related to broken rotor fault depend on slip. in industrial environment due to some phenomena - such as load oscillation, other faults an...

Tlie control of a doubly-fed induction machine (DFM) with a id without tlie use of a rotor position encoder is examined. First, a stator fliix linkage oriented control scheme for power and speed control, with a position encoder, shows the high performance control capabilities of this control arrangement and serves a s foundation for the sensorless scheme. The power-control method is then applie...

We report two-dimensional (2D) (17)O multiple-quantum magic-angle spinning (MQMAS) NMR spectra for four (17)O-labeled organic compounds: [(17)O(2)]-D-alanine (1), potassium hydrogen [(17)O(4)]dibenzoate (2), [(17)O(4)]-D,L-glutamic acid.HCl (3) and [2,4-(17)O(2)]uracil (4). The high spectral resolution observed in the 2D (17)O MQMAS NMR spectra allows extraction of precise (17)O NMR parameters ...

The sensorless control of an axial flux permanent magnet motor drive is proposed and tested. The motor is not purposely designed for sensorless control and shows a very small inherent saliency. This significantly affects the saliency-based position estimation in the low speed region. Other nonidealities, such as the non-sinusoidal back-EMF waveforms and possible misalignment between stator and ...

LiMn2O4 has been studied using magic-angle-spinning nuclear magnetic resonance (MAS NMR). 1D MAS NMR shows three Li resonances assigned to different crystallographic sites. At low temperatures an extra peak appears, indicating charge ordering of Mn3+ and Mn4+. Direct observation of the lithium dynamics was possible using rotor-synchronized 2D exchange NMR. A millisecond time scale exchange of l...

The use of rotor-synchronized Hahn-echo pulse train (RS-HEPT) H decoupling, in a MAS (Magic Angle Spinning) N spin-echo NMR experiment allows the use of longer the spin-echo durations compared to the case when conventional decoupling is applied, hence enabling the accurate determination of very small J couplings down to a few Hz. Here, a thorough numerical analysis of the N spin-echo under RS-H...