Application and Analysis of constant power frosting heater in refrigerator

- May 05, 2020-

The defrosting heater is an indispensable heating device in the air-cooled refrigerator. It is generally fixed below the evaporator, and the defrosting heater needs to be used to defrost the surface of the evaporator at intervals. However, during the operation of the heater, fluctuations in the working current or working voltage of the heater will directly cause the heating power of the heater to change, which in turn causes the heating temperature of the heater to change: when the heating temperature of the heater is low , It is easy to make the defrosted water re-freeze, so that it cannot flow out from inside the refrigerator, affecting the defrosting effect of the refrigerator; or when the heating temperature of the heater is too high, it may cause the plastic parts around the heater to deform, Affect the life span of the refrigerator.

Chinese scholars have conducted a lot of research on the control method of defrost heaters for air-cooled refrigerators. When the working ratio) is less than or equal to 1, the heater is controlled to heat according to the working ratio, so that the average heating power within one operating cycle after the heater is heating according to the working ratio is equal to the preset heating power. Chen Xing⑺ realized the function of controlling the defrost heater through the hardware circuit through the newly added temperature control circuit, that is, no matter what state the microcontroller is in, when the defrost temperature sensor RV temperature is too high, the defrost heater is forced Power off, to avoid the failure of the heating control system to cause the heating temperature to be too high to cause deformation or ignition of the tank, improve the safety performance of the product. Xiang Zhe Shuang et al. Used the defrost sensor to monitor the temperature change of the evaporator to directly monitor the refrigeration power of the refrigerator, and calculated it through the refrigerator control panel MCU. Adjust according to the frost level of the evaporator.