Abstract: In order to solve the problem of high frequency noise in the compressor of household variable frequency air conditioning, the noise source and transmission path are studied. In terms of noise source, studied the mechanism of high frequency noise based on the pulse width control technology and harmonic theory of motor air gap magnetic field, recognized that 5000 Hz noise were mainly caused by the interaction between controller's carrier frequency and rotor's magneto motive force which formed a harmonic electromagnetic wave. Then conducted an experimental verification on correlation of 5000 Hz noise and carrier frequency. In terms of the transfer path, recognized that the shell resonance caused by the weak rigidity in the upper cavity area of the motor was the core reason that leaded to the high noise of the compressor at 5000 Hz. As a result, two optimization schemes of adding a separator in the upper cavity region of the motor and reducing the upper cavity of the motor were proposed through the acoustic radiation simulation analysis method .Then verified the effectiveness of above two optimization schemes that reduced 5.8 dB(A) and 6.9 dB(A) at 5000 Hz noise respectively and provided a theoretical basis and guidance for the improvement of high frequency noise in the compressor of household variable frequency air conditioning.

Key words: Carrier frequency, Acoustic radiation, High-frequency noise, Compressor