Sensorless speed measurement of induction machines using Short Time Fourier Transformation

FEM approach for diagnosis of induction machines' non‐adjacent broken rotor bars by short‐time Fourier transform spectrogram

“…The aim of these techniques is to obtain information from the signal's spectral energy density distribution about where the harmonic trajectories lie regarding frequency and, at the same time, when the transitions of these frequencies happen in time. Among them short‐time Fourier transform (STFT) is one of the most frequently used, due to its simplicity in terms of low computational complexity [4–6, 8] and availability in commercial software packages.…”

On the broken rotor bar diagnosis using time–frequency analysis: ‘Is one spectral representation enough for the characterisation of monitored signals?’

“…On the other hand, a t-f representation without system oriented fine tuning of parameters -which in this case relate to the slip and sampling frequency -might also result in information loss. It should also be noted that the approach of this system oriented parameter tuning can be used for t-f process like the ones described in [32][33][34] or [53][54][55][56][57] as an initialisation pre-setting and finetuning; it is also eligible to define the two extreme limits where these methods or similar types of analyses can be tested, when aiming to extract different pieces of information in two stages. At one of these extremes shown in Fig.…”

“…Furthermore, with the latest advances in digital signal processing, a breeding ground has been offered for deeper insight into the characteristics of signals and their included components. Time-frequency representations like the Wigner-Ville distribution (WVD) [31][32][33] and the short-time Fourier transform (STFT) [33][34][35][36] provide a visualisation of the squared spectral density on a lattice gridded by time and frequency, which is called the timefrequency plane and is of fixed resolution [36][37][38]. On the other hand, techniques like the wavelet transformation [23,36,39] offer improved resolution due to the scaled tiling of the grid but are governed from a higher level of design and computational complexity [36,39].…”

Sensorless Speed Estimation of an Inverter-Fed Induction Motor Using the Supply-Side Current

“…When an IM is healthy and ideal, the center of the rotor coincides completely with the stator bore center creating a uniform airgap inside the IM. IM eccentricity is the situation where an asymmetrical airgap appears due to a deficiency in the manufacturing and installation process [9], [12]. In fact, an acceptable level of airgap eccentricity is 10% for a healthy IM [15].…”

“…Shi et al first utilized the Hilbert transform to demodulate the stator current, the speed harmonic component was estimated by the Interpolated Fast Fourier Transform (IFFT) algorithm to detect IM speed [8]. Wang et al presented a high resolution spectrum analysis of SVAF to detect IM speed under the transient conditions [9]. Song et al used Teager-Kaiser Energy Operator (TKEO) integrated with IFFT to estimate the speed of a line-connected IM [10].…”