固态Marx发生器的自动控制研究

Research on automatic control of solid state Marx generator

为了进一步推广固态Marx发生器的应用,实现输出脉冲波形的直观显示,提高电压调节精度,缩短充电调压时间,有必要对固态Marx发生器的自动控制进行研究。以现场可编译门阵列(FPGA)作为控制器,将输出电压、频率、脉宽、过电流阈值等参数以及故障检测及指示直接显示在液晶屏上,实现可视化设置和调节,在固态Marx发生器的输出端并联分压电路和高速数模转换电路,对输出的高压脉冲采样,一方面用于闭环PID控制实现分段式快速充电和输出电压精准化调节,另一方面用于在虚拟示波器中实时显示输出脉冲电压的基本波形。此外,在电路中加入了故障检测和保护机制,迅速检测电路中出现的过温、过电流等故障并对其及时停机响应以保护脉冲电源和操作人员安全。在20级的固态方波Marx发生器样机中产生的重复频率方波脉冲电压波形表明,该样机已经初步实现自动化控制,并能可靠运行。

To further promote the application of solid-state Marx generators,enable them with the visual display of output pulse waveforms,more accurate regulation of voltage,and shorter charging regulation time,it is necessary to study the automatic control of solid-state Marx generator.In this paper,with a field programmable gate array(FPGA)as the controller,the output voltage,frequency,pulse width,overcurrent threshold value,and other parameters,as well as fault detection and indication,are all directly displayed on the LCD screen to realize visible settings and adjustment.In solid-state Marx generators,a voltage dividing circuit in parallel with the output and a high-speed analog-digital conversion circuit is used to realize high-voltage pulse sampling of the output.With these sampled voltage values,on the one hand,the closed-loop segmented PID control can be realized to achieve fast charging and precise adjustment of the output voltage.On the other hand,the basic waveform of the real-time pulses can be displayed in the virtual oscilloscope.Besides,fault detection and protection mechanisms have been added to the circuit to quickly detect overtemperature,overcurrent,and other faults in the circuit and respond to their timely shutdown to protect the pulse generators and the operators.The voltage waveforms of repetitive square pulses generated by the topology of a 20-stage solid-state square Marx generator indicate that the basic automatical control of this solid-state Marx generator has been realized and it can operate reliably.