土壤射频处理系统设计与试验

Design and test of soil RF processing system

针对土壤病虫害物理绿色防控的需求,设计了一套射频处理系统,由射频发生器、匹配器、屏蔽装置、工作电极、冷却系统、温度传感器和控制系统等部件组成。该系统通过射频发生器产生高频电磁波,作用在极板间土壤,使土壤被加热,杀灭病虫害,达到消毒的目的。系统工作频率13.56MHz,额定输出功率10kW,输出阻抗50Ω,反射功率小于300W,响应时间小于50ms;在10kW额定功率时,电磁辐射最大为3V/m,小于25V/m的国际标准要求;设计的四种形式电极,阻抗范围为30~80Ω,通过匹配器能自动与射频发生器匹配。试验结果表明,纵向平行板、圆环面两种电极结构处理土壤时,温升速率较高,温度分布均匀性较好。经过48h连续考核,系统各项指标均达到要求,工作稳定、可靠,能满足土壤射频处理的要求。

According to the demand of physical green control of soil diseases and insect pests,a set of RF processing system is designed,which is composed of RF generator,matching device,shielding device,working electrode,cooling system,temperature sensor and control system.The system generates high-frequency electromagnetic wave through RF generator,which acts on the soil between plates,heating the soil,killing pests and diseases,and achieving the purpose of disinfection.The system has a working frequency of 13.56MHz,a rated output power of 10kW,an output impedance of 50Ω,a reflected power of less than 300Wand a response time of less than 50 ms.At 10kW rated power,the maximum electromagnetic radiation is 3 V/m,less than the international standard requirements of 25V/m.Four kinds of electrodes are designed,the impedance range is 30~80Ω,and they can match with RF generator automatically through matching device.The results show that the temperature rise rate is higher and the temperature distribution uniformity is better when the soil is treated with two kinds of electrode structures:longitudinal parallel plate and circular surface.After 48hours of continuous assessment,all indexes of the system are up to the requirements,stable and reliable,and can meet the requirements of soil RF treatment.