Research On Low-temperature Plasma Sterilization Power Supply Based On DSP

The low-temperature plasma has very wide prospects in industrial application. At present, most studies of producing plasma are focused on those produced by Dielectric Barrier Discharge (DBD) under atmosphere. Because most of the conventional sterilization techniques have some disadvantages in such a society, the theory that the low-temperature plasma can kill bacilli without pollution is used in this paper. And the effect of plasma produced by DBD correlates directly with voltage, frequency and wave-form of the power supply. As a result, the low-temperature plasma sterilization power, which has higher voltage and has frequency of the power supply, should be studied as soon as possible.This design adopted the input of 380 voltage alternating current, which becomes direct current by three-phase rectification, then adjusted the voltage through Buck circuit, converted into alternating current through IGBT, realized the output of high frequency high voltage sinusoidal wave through inductor to leach wave and high frequency transformer to elevate voltage .At last, whether to start to kill bacilli is based on the analysis of ultraviolet radiation intensity examination.The goals,Output voltage, 10~20kV can be adjusted.Output frequency, 10~20kHz can be adjusted.Output power, 5~10kWThe mathematical model of low-temperature plasma sterilization power is analyzed based on the structure of discharge. This thesis has analyzed the topology structure about the poser, and analyzed the rectification circuit, Buck circuit, inverter circuit, drive and protection, also supplied the main parameters based on the study. At the same time, the TMS320LF2407A DSP that is one kind product of TI Company, on which the main circuits has been designed and the main program has been made in this study.This innovation of this thesis is that a new equivalent circuit of plasma discharge has been designed based on the researches at home and abroad, which is divided into starting circuit with high-voltage and starting with normal-voltage. At the same time, it analyzed the model,which laid a foundation for the choice of devices and the determination of transformer parameters.Based on the academic study, compared with the result of experiments, which has proved the project is accord with the studies. And Experimental results of killing bacilli have demonstrated this power supply has many advantages, such as low-temperature, short time, no residuals, no pollution, safe and reliable, and so on, and also has broad prospect and practical value.