Active Ultrasonic Vibration Control of Electrical Equipment: Correlation Signal Processing

The scheme and algorithms electrical equipment's active vibration control using remote ultrasonic sensing of vibrating surfaces are proposed. Active ultrasonic sensing has a higher selectivity than passive noise measurement of electrical equipment and has less restrictions on application conditions than optical (laser) methods. It is shown that modulation (frequency and phase) of ultrasonic pulses reflected from the vibrating surface allows to control equipment vibrations in a wide frequency range. For this purpose, correlation and spectral processing of ultrasonic signals is proposed. It can be implemented both by analog and digital means. The results of modeling and laboratory experiments are presented. The digital system of shaping and processing of signals is realized using an programmable logic device. The basis of the proposed method is a calculation of the cross correlation function between the signal reflected from the controlled object and the reference signal with a given frequency or phase modulation. It makes it possible to significantly increase the resolution of ultrasonic pulse measurements and, depending on the vibration frequency, to implement effective adaptive vibration control algorithms. The proposed approach allows fixing high-frequency vibrations (> 1 kHz) with the amplitude from units of microns and low-frequency vibrations (<0.5 Hz) with amplitude of a unit of millimeters.