Acoustic Noise Characterization of Space Vector Modulated Induction Motor Drives – An Experimental Approach

Abstract

This paper presents an experimental procedure to determine the acoustic and vibration behavior of an inverter fed induction motor based on measurements of current spectrum, acoustic noise spectrum, overall noise in dB, and overall Aweighted noise in dBA. Measurements are carried out on spacevector modulated 8-hp and 3-hp induction motor drives over a range of carrier frequencies at different modulation frequencies.The experimental data helps to distinguish between regions of high and low acoustic noise levels. The measurements also bring out the impact of carrier frequency on the acoustic noise. The sensitivity of the overall noise to carrier frequency is indicative of the relative dominance of the high-frequency electromagnetic noise over mechanical and aerodynamic components of noise. Based on the measured current and acoustic noise spectra, the ratio of dynamic deflection on the stator surface to the product of fundamental and harmonic current amplitudes is obtained at each operating point. The variation of this ratio of deflection to current product with carrier frequency indicates the resonant frequency clearly and also gives a measure of the amplification of vibration at frequencies close to the resonant frequency. This ratio is useful to predict the magnitude of acoustic noise corresponding to significant time-harmonic currents flowing in the stator winding.

Variable-Switching Frequency PWM Technique for Induction Motor Drive to Spread Acoustic Noise Spectrum With Reduced Current Ripple

“…Still, the acoustic noise components around 4 kHz are not too high. This may be attributed to the amplification factor not rising very sharply close to the resonant frequency for this specific motor [3]. The noise spectrum is fairly dispersed with VFPWM as demonstrated by Fig.…”

“…The resonant frequency of the 6-kW motor has been reported to be around 4 kHz [3], [26]. Hence, in order to study the effect of including the resonant frequency within the switching frequency range, the experiment is repeated with a nominal carrier frequency, f c,nom of 3 kHz.…”

“…One main reason for acoustic noise emission is the injection of harmonic currents by the voltage source inverter (VSI) feeding the induction motor. When the inverter is pulse width modulated at a fixed switching frequency, the acoustic noise emitted by the motor is concentrated in narrow bands around integral multiples of the inverter switching frequency [1]- [3]. Sine pulse-width modulation (SPWM) and conventional space vector pulsewidth modulation (CSVPWM) are well known fixed switching frequency pulse-width modulation (PWM) methods used in industry [4].…”

Experimental Comparison of Conventional and Bus-Clamping PWM Methods Based on Electrical and Acoustic Noise Spectra of Induction Motor Drives

“…Further comparison between BCPWM methods shows that 30 • BCPWM is better compared to 60 • BCPWM, in terms N 1d . The resonant frequency of the 6-kW motor is estimated as 4 kHz [12], [38] and magnetic force waves in its proximity are boosted up whereas other force waves are attenuated. Because of this, N 2d is significantly reduced, compared to N 1d .…”

Experimental study of PWM strategy effect on acoustic noise generated by inverter‐fed induction machine

“…Accordingly, space vector PWM (SVPWM) would offer reduced current and torque ripples, compared with SPWM . The voltage harmonics were also decreased and were concentrated around integer multiples of the VSI switching frequency . The optimal modulation, otherwise known as the selective harmonic elimination PWM (SHEPWM), would determine in advance the switching angles, taking into account the amplitude of the desired output voltage and the harmonics to be eliminated .…”