红外式冰箱结霜传感器的设计和试验研究

Design and Experimental Study of Infrared Refrigerator Frost Sensor

现有无霜冰箱中多采用机械定时器定时除霜,为了解决此种方式除霜误判率高和能耗大等缺点,利用光在霜内发生的散射、反射、折射等作用的光学特性,设计了可以测量霜厚的红外式冰箱结霜传感器。该传感器以红外收发对管为核心,其机械结构可使其安装在冰箱蒸发器表面。设计了传感器的信号处理电路和单片机程序。传感器和冰箱的压缩机和除霜设备协同工作组成自动除霜系统,使冰箱工作在无霜状态。在结霜试验平台下进行的单件和多件一致性实验表明该传感器在0～5 mm内测量霜厚相对误差小于20%,绝对误差小于1 mm,满足冰箱探霜的要求。结冰实验表明结霜探测不受结冰的干扰。

Most of current frost-free refrigerators use mechanical timer defrost device to defrost. It has drawback of high mis- judgment rate and high energy consumption. In order to solve the problem, an infrared refrigerator frost sensor which can detect frost thickness was designed. It adopted the optical property that the light can scatter, reflect, adsorb in the frost. Its core is infrared emit- ting and receiving diode and its mechanical structure allows it to be installed on the refrigerator evaporator surface. Signal process- ing circuit and MCU program of the sensor was designed. The sensor can work with refrigerator compressor to form an automatic de- frost system, making the refrigerator work in frost-free status. The consistency experiments on frost experiment platform prove that when frost thickness is within 0 to 5 mm, the absolute error of the sensor is less than 1 mm, and the relative error is less than 20%, it meets the requirements of frost detection. Freezing experiments prove the sensor is not affected by the interference from freezing.