Research On Bipolar Square Wave High-Voltage Pulse Power Supply For Sterilization

With the improvement of people's material living standards,consumers have higher and higher requirements for food safety and quality.High-pressure pulsed electric field sterilization technology(PEF)as a non-thermal sterilization technology relies on its extremely short sterilization time and low energy consumption,Low temperature rise,no pollution,good penetration and other advantages have obtained extensive research in the laboratory.However,there are few bipolar high-pressure pulse square wave devices used for liquid(milk,beer,etc.)sterilization.In this paper,a high-voltage pulse generator capable of generating bipolar square waves is developed for liquid sterilization experiments And the generator can also realize the pulse repetition frequency,pulse width,pulse amplitude can be adjusted.In this paper,the high-voltage pulse electric field(PEF)sterilization technology and its necessary devices are introduced,and the research status of its main component,high-voltage pulse generator,is analyzed at home and abroad.Through the analysis of the common pulse generator working principle and topological structure,the basic principle of the device is determined based on Marx circuit.At the same time,through the analysis of the current common switching devices,the IGBT module is selected as the switching device.The overall structure of the pulse generator is designed.The pulse generator is composed of the main circuit and the control circuit.The main circuit is composed of the high-voltage DC power supply,the pulse forming circuit and the processing room(load).The control circuit is composed of the signal generating circuit and the high-power IGBT driving circuit.The main circuit is designed,and two kinds of new bipolar pulse forming circuits are proposed based on the research of the existing bipolar circuit technology.The most suitable bipolar pulse forming circuit is selected by comparing the withstand voltage,loss and output voltage drop of the switching element in the circuit.The system performance parameters of the pulse generator are established,and the components of the pulse forming circuit are calculated and selected.Through the simulation analysis of the main circuit structure,the output power of the pulse generator and the relevant parameters of the high-voltage DC power supply are determined,and the design of the high-voltage DC power supply is completed.The control circuit is designed,and FPGA is selected as the main control chip.Aiming at the phenomenon of pulse tailing after the end of pulse discharge,the discharge circuit of residual charge of resistive capacitive load is designed,and each switch is programmed in a controllable way.In addition,the selection of high-power driver chip and the design of external expansion circuit are carried out,the main circuit and control circuit are connected,and the optical fiber isolation is used in the design of strong and weak current isolation.