Study On Suppression Technologies Of Radiation Disturbance Of High Frequency Hot-sealing Machine

Since the invention of the electromagnetic theory of Maxwell, Hertz discovered electromagnetic waves; the concept of electromagnetic energy is related with people's lives closely. In the Information Society, due to the extensive application of electromagnetic energy, and various electrical and electronic equipment continue to emerge. Electromagnetic environment is deteriorated increasingly, and electromagnetic interference has become a hot topic. All countries in the world have begun to pay great attention to the increasingly complex electromagnetic environment and its impact. Thus, electromagnetic compatibility (EMC) and electromagnetic environment become new subject areas which have rapid development.The theory and practice show that, any of electromagnetic disturbances must have three basic conditions. First should have the source of disturbance, furthermore, have transmission path of disturbance energy, the third is that there must be sensitive devices. So they have become into the three elements of electromagnetic disturbance.The subject is imbursed by Natural Science Foundation Committee(NSFC), and the paper mainly studies around three elements of the electromagnetic disturbance which are disturbance source,coupling path and sensitive equipment, and focuses on radiation disturbance characteristics of high frequency hot-sealing machine, and illustrates the suppression technologies. The main contents are the following:1. The paper firstly introduces the concept of EMC,the researched contect of EMC and the current research in domestic and foreign, and makes depth comprehension to EMC.2. It discusses and analyses the characteristic of disturbance sources and coupling path, and mainly illustrates the characteristic of conductivity coupling,shared impedance coupling,induction coupling and radiation coupling. The it introduces suppression technologies of shielding,suspension and filter. Based on these suppression technologies, the conductivity coupling is sloved by shielding and filter, and the paper adopts grounding method to slove shared impedance coupling, and couping is sloved by shielding,changing the line direction and grounding method, and the radiation coupling is solve by grounding method usually. So it provides theoretical basic for actual problems.3. It analyses the prediction model of EMC, and makes mathematical model applying field method and circuit method for disturbance source,coupling path and sensitive equipment. According to these theoty, it focuses on the study of radiation disturbance mathematical model. Then it studies on the mathematical model of common mode voltage and differential model voltage, and visually illustrates the characteristic of electromagnetic radiation field which forms strong radiation to surrounding envirment and equipments. It provides theoretical basic and analysis method for actual problems.4. Lastly, the paper analyses the principle and structure of high frequency hot-sealing machine, and introduces the urgency to solve its problems. Applying half anechoic chamber, it makes a lot of experiments to hot-sealing machine in order to find out the disturbance sources. Then considering cost and efficiency comprehensively, it adds a parallel resonant circuit to counteract excrescent radiation energy on the hot-sealing head, which forms a reverse electromagnetic field. In order to reduce radiation energy furtherly, it adopts shielding technology on the sheet copper feeder of high power, and it adopts filter technology in the high frequency oscillation circuit. Experimental results show that the adopted measures are feasible; it reduces the intensity of radiation disturbance, and solves the interference problem to surroundings and equipment. It also guarantees the safety of the staff and improves work efficiency.