高重复频率MOSFET脉冲调制技术研究

【作者】 张良；

【导师】 章林文； 刘承俊；

【作者基本信息】 中国工程物理研究院 ， 核技术及应用， 2007， 硕士

【摘要】 能产生短脉冲、快上升沿、快下降沿、高电压、大电流且能工作在兆赫兹频率的固体调制器是脉冲功率技术的一个重要发展方向。本文介绍了由功率MOSFET器件组成的固体调制器的基本工作原理，设计思路。并且由固体调制器的基本框架图，设计了固体调制器的原型。完整的固体调制器由控制系统，辅助供电部分，开关主体和负载组成。控制系统采用单片机和CPLD为硬件核心，设计了宽度，频率，个数可调的脉冲信号发生器，作为固体调制器的触发信号源。其输出的最小脉宽为12.5ns，多个脉冲的一致性良好。触发信号源的输出采用光纤隔离电路，来增强其抗干扰能力。根据功率MOSFET的工作原理，分别用分离元件和集成驱动芯片搭建了驱动电路。并且通过电路仿真结合实验结果，确定了驱动电路的主要参数，分析了电路中干扰的来源并给出改进的方案。驱动电路的供电采用可级联的DC／DC模块搭建。在单个功率MOSFET开关的基础上，讨论了功率回路的选择和保护电路，并分别进行了6个MOSFET并联和4个MOSFET串联的实验，同样使用电路仿真找到对输出波形产生影响的主要参数，并且给出改进方案。在详细比较直接串联和感应叠加两种产生高压的方法后，最后采用感应叠加的方式来设计调制器，叠加器的设计思路也被详细给出。最终设计的调制器由3个开关模块叠加而成，在充电电压为800V时，可以得到最短脉宽为33.8ns，前沿为13.9ns，幅度为2.20kV的脉冲。多脉冲情况下也得到良好的脉冲一致性。更多还原

【Abstract】 Solid state modulator with multi-pulse burst capability in mega Hertz, fast rise and fall times and width agility is the hotspot of pulse power technology. In this paper, the base principle and designing method of the solid state modulator based on power MOSFET devices are introduced. The prototype of the modulator is introduced and the experimental results are given.The whole solid state modulator was composed of control system, power supply supplemental system, switch circuits, and the load. The kernel hardware of control system was composed of Micro Control Unit (MCU) and Complex Program Logic Device (CPLD). It could generate trigger signal with shortest pulse width of 12.5ns for the driver circuit of power MOSFET, and it also had good performance in multi pulses situation. Optical association circuits were used to protect the control system against the high voltage of the switch circuits.Two types of driver circuits were designed according to the principle of power MOSFET. One was designed by separated components and the other was by integrated driver chip. Circuit simulations were used to help to analyze the experiment results. The reasons of cross talk in print circuit board were analyzed and improving ways were given. Power supply for driver circuits was designed by DC/DC modules which could work in series connection mode.After the experiments of Single MOSFET switch, the switch with six MOSFETs parallel connecting and switch with four MOSFETs serial connecting were separated tested. Circuit simulations were also done to improve the experimental results.The adder configuration was chosen to set up the prototype modulator for the adder topology had many advantages than the direct serial method. The adder transformers were designed and tested.The modulator finally designed composed of three adder modules. The single pulse with shortest pulse width of 33.8ns, rise time of 13.9ns, amplitude of 2.2kV was obtained under charging voltage of 800V. Good experiment results were also got in multi pulses output mode.更多还原