Title :
Influence of the fan cowl on the acoustic noise radiated from PWM controlled induction machines
Author :
Zhu, Z.Q. ; Xu, L. ; Howe, D.
Author_Institution :
Dept. of Electron. & Electr. Eng., Sheffield Univ., UK
Abstract :
The influence of the fan cowl, particularly the material of which it is made, on the acoustic noise emitted from PWM controlled induction machines is investigated. It is shown that there are significant harmonic excitation forces which can cause mechanical resonances of the fan cowl. The mechanical behaviour of both metal and plastic cowls is measured, using impulse force tests and random PWM excitation. The noise spectra and sound pressure level of a 1.5 kW 3-phase induction machine when equipped with a metal and a plastic fan cowl are investigated, and the noise spectra when the machine is supplied from sub-harmonic PWM, space vector PWM and random PWM inverter are compared. It shows that a metal fan cowl can significantly amplify the noise level, whilst the noise level with a plastic fan cowl is effectively the same as that with the cowl removed
Keywords :
DC-AC power convertors; PWM invertors; acoustic noise; exciters; harmonics; induction motors; 1.5 kW; PWM-controlled induction machines; acoustic noise radiation; fan cowl influence; harmonic excitation forces; impulse force tests; mechanical behaviour; mechanical resonances; metal cowls; noise level amplification; noise spectra; plastic cowls; random PWM excitation; random PWM inverters; sound pressure level; space vector PWM invertor; sub-harmonic PWM invertors; three-phase induction machine; Acoustic materials; Acoustic noise; Force measurement; Induction machines; Noise level; Plastics; Pulse width modulation; Pulse width modulation inverters; Resonance; Space vector pulse width modulation;
Conference_Titel :
Electric Machines and Drives Conference, 2001. IEMDC 2001. IEEE International
Conference_Location :
Cambridge, MA
Print_ISBN :
0-7803-7091-0
DOI :
10.1109/IEMDC.2001.939302
