Abstract: Defrosting of air-cooled refrigerator evaporator is heated by heating wire to melt the ice on the evaporator into water, which is discharged to the evaporating dish for evaporation. After defrosting, in order to make the refrigerator room warm quickly, the compressor and fan usually run at the highest speed. The sound of compressor and fan running at high speed is much louder than that of normal operation. This kind of sound is easy to be perceived by the user at night when the user is resting, which directly affects the user's sleep. Therefore, it is necessary to adjust the time of high speed of compressor and fan to avoid the rest period of users. First of all, the user's rest period is intelligently identified, and then the silence mode is entered. Through the control logic of the main control board, the rotation speed of the compressor and fan and the time of high frequency operation are adjusted, so as to achieve the purpose of refrigerator night silence.

Key words: Frost melting period, Compressor noise, Control logic, Quiet mode