Experimental Investigation on Electromagnetic Vibration Characteristics of Induction Motor Fed by Inverter

In this paper, an induction motor with the slot combination of 30/22 is taken as an example to study the vibration characteristics under different carrier frequencies, loads and speeds. First, an analytical model of electromagnetic force waves considering the harmonic current of the inverter is established to analyze the source of electromagnetic force waves. Then, a comparative analysis of the current, flux density, and vibration spectra under sinusoidal and variable frequency power supplies is conducted. Finally, the vibration characteristics of the studied motor under different carrier frequencies, loads and speeds are experimentally analyzed. The results show that as the carrier frequency increases, the vibration is effectively suppressed, but the suppression effect gradually weakens. Compared with the carrier frequency, the load change has little effect on the vibration. During the speed regulation process, although the amplitude of the rotor slot harmonic flux density changes little, the vibration weakens because its frequency gradually moves away from the natural frequency; this shows that optimizing the motor from the aspect of avoiding the main harmonic frequency of the natural frequency can also effectively suppress the vibration.