新型高压脉冲电场灭菌电源的研制

Development of new high voltage pulsed electric field sterilization power supply

为了满足高压脉冲电场灭菌的要求,提出一种采用固态开关与半桥式Marx发生器结合的新型高压脉冲电场灭菌电源。此电源通过对经典Marx电路结构进行改进,解决了经典Marx电路直流充电电源与高压端的隔离问题,而且具有良好的电压钳位功能和负载适应能力。分析了半桥式Marx电路在阻性、容性、感性负载下的工作过程以及放电过程中固态开关未正常工作时电压钳位效果,此电源由可调直流电源、5级半桥式Marx发生器和控制保护电路三部分组成,使用现场可编程门阵列(FPGA)作为控制器产生控制信号,使用光纤隔离的方式为主回路提供控制信号。电源可输出电压幅值10 kV,每秒最大脉冲数1 000,脉冲上升时间300 ns,最大脉宽20μs的高压方波脉冲,并且重复电压幅值、频率,脉宽可调,能够满足高压脉冲灭菌实验的需求。

In order to meet the requirements of high voltage pulse electric field sterilization, a novel high voltage pulse electric field sterilization power supply combining solid-state switch and half-bridge Marx generator was proposed. By improving the structure of Marx circuit, this power supply solves the isolation problem between dc charging power supply of Marx circuit and high voltage terminal, and has good voltage clamp function and load adaptability. The working process of the half-bridge Marx circuit under resistive, capacitive and inductive loads and the voltage clamping effect when the solid-state switch does not work properly in the discharge process were analyzed in detail. The power supply is composed of adjustable DC power supply, five-stage half-bridge Marx generator and control protection circuit. Field programmable gate array(FPGA) was used as the controller to generate control signals, and optical fiber isolation was used to provide control signals for the main loop. The power supply can output high voltage square wave pulse with voltage amplitude of 10 kV, maximum pulse number of 1 000 per second, pulse rise time of 300 ns, maximum pulse width of 20 μs, and the repeated voltage amplitude, frequency and pulse width are adjustable, which meet the requirements of high voltage pulse sterilization experiment.