TIME-FREQUENCY ANALYSIS OF NON-STATIONARY THREE PHASE SIGNALS

Abstract: New method of observation and diagnosis of inverter-fed induction motor drives is developed and tested. Unsymmetrical conditions concerning the machine impedances or valves operation are reflected in the spectrum of the current space-phasor. We estimate the spectrum of the space-phasor with the help of the Wigner-Ville distribution (WVD) and we obtain its time-frequency representation with excellent time and frequency resolution. The proposed method is tested with nonstationary multiple-component signals occurring during the fault operation of inverter-fed drives and transmission lines. Copyright © 2002 IFA