Study of Sound Harmonics on Induction Motor control by Inverter

Abstract

Abstract

This article presents the study of Sound Harmonics on Induction Motor control by Inverter AC drives. The
propose technique does measure the harmonics of sound generated by induction motor without contact. Moreover, from the measured harmonic level, we can analyze the operation of induction motor control by inverter AC drives. Therefore, the studies of sound harmonic consist of two main procedures. The first procedure is used to measure the electrical properties comparing with the characteristic of sound harmonic. The second procedure is used to simulate of the operation on MATLAB / SIMULINK. For these two procedure, we set the frequency of the motor ( fm) at 5, 25, 50, 75 Hz for controlling the speed rate of motor, then adjusts the frequency switching ( fs ) of the inverter at 4, 8, 12kHz for controlling the stability of motor. From the experiment results, harmonic at the motor frequency (fm) at 75 Hz and switching frequency (fs) at 12 kHz, Harmonic, there are high amplitude of 200V and a sound level of 41.38 - 63.01 dB. But, at switching frequency (fs) at 4 kHz, Harmonic, there are low amplitude of 40V and a sound level of 41.40 - 71.95 dB. Then, comparison with the simulation results on MATLAB/SIMULINK, it appears an average error of 1.19%. In conclusion, the harmonic amplitude is directly proportional to the frequency of switching. But, it’s inversely proportional to the sound level because at the high switching frequency will cause a rotor current to more pure sinusoidal wave. The rotation of the motor is more stable and smooth and sound level is decreases.