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Unlike a fixed-frequency power supply, the voltage supplying an inverter-fed motor is heavily corrupted by noises, which are produced from high-frequency switching leading to noisy stator currents. To extract useful information from stator-current measurements, a theoretically sound and robust de-noising method is required. The effective filtering of these noises is difficult with certain frequency-domain techniques, such as Fourier transform or Wavelet analysis, because some noises have frequencies overlapping with those of the actual signals, and some have high noise-to-frequency ratios. In order to analyze the statistical signatures of different types of signals, a certain number is required of the individual signals to be de-noised without sacrificing the individual characteristic and quantity of the signals. An ensemble and individual noised reduction (EINR) method is proposed as the extension of the common …