CAPACITIVE SENSOR FOR SURFACE ICING CONTROL

Icing of the surfaces of objects leads to a decrease in their technical characteristics and can lead to emergency situations and equipment failure. For effective control of deicing systems, it is required to monitor the condition of the surface with the help of specialized sensors. One of the most promising ways to detect icing is the capacitive method based on a significant difference in the dielectric permittivity of water in liquid and solid aggregate states. Considering that the capacitance of the sensor depends on both the measurement frequency and the configuration and size of the electrodes, the analysis of the characteristics of capacitors of different geometries under different conditions was carried out and the optimal shape of the sensor and the frequency of measurements were determined. The operation of the electronic circuit of the developed icing control sensor is based on comparing the reference voltage with the voltage depending on the capacitance value of the measuring capacitor. The capacitace–voltage converter is built on the basis of a high-pass filter and a single-half-period rectifier. To improve the accuracy of determining the presence of ice on the surface, a scheme is proposed in which the capacitance of the measuring capacitor is monitored at two frequencies. The considered capacitive sensors for monitoring surface icing have a fairly simple design, but at the same time effectively fulfill their task.