Induction Motors Speed Estimation by Rotor Slot Harmonics Frequency Using Zoom Improved Chirp-Z Transform Algorithm

Abstract

This paper analyzes the digital signal processing techniques and estimates induction motor (IM) rotational speed operating in stationary or non-stationary conditions. Rotor slot harmonics present in the stator current waveform are used to estimate the induction motor speed with a given or identified rotor slot numbers. This paper’s contribution is the following: First, zoom improved short-time Chirp-Z transform is used to find supply frequency and the rotor slot harmonic frequency to improve the estimation accuracy without increasing computing complexity. Second, a technique is described that can be used to determine whether or not a motor can generate principal slot harmonics (PSH). Finally, an algorithm is designed to figure out the perfect window length and estimate the motors’ speed. This proposed technique was investigated when the motor was fed by an inverter-fed supply driving a variable load and operating in non-stationary conditions. Experimental test results on 5.5 kW and 22 kW induction motors have confirmed the correctness of this method.

Research on fault identification of high-voltage circuit breakers with characteristics of voiceprint information

“…Research shows that circuit breaker fault diagnosis generally involves three main aspects: data acquisition, feature extraction, and fault diagnosis identification. In terms of time–frequency transformation, the main methods applied include Fourier transform 8 , wavelet transform 9 , chirp-z transform 10 , Hilbert transform 11 , S transform 12 , 13 , and so on. In the application of Fourier transform, as a global transformation method, Fourier transform lacks the function of time and frequency localization, and is generally suitable for analyzing stationary signals.…”