激光电源脉冲功率切换电路稳定工作是电源可靠性的保证。电路参数选取直接影响晶闸管、二极管的工况，而晶闸管的良好工况是保证切换激光电源长期可靠运行的基本条件。基于PSCAD软件建立切换电路的仿真模型，重点仿真分析了阻容电路参数配置、限流电阻、并联晶闸管触发同步性对晶闸管和二极管的影响。仿真结果表明，电流上升率过大是晶闸管门极损坏的原因，关断支路中的反向过压是二极管损坏的原因。并针对实际电路，提出晶闸管二极管保护的优化配置方案。

The pulsed power switching circuit is the basic guarantee of a reliable laser power supply. Parameters selection of the switching circuit directly influences the operating condition of thyristors and diodes, which is the basic condition to guarantee the long-term operating reliability of the laser power supply system. Simulation analysis of the switching circuit is carried out in this paper based on PSCAD software, and operating conditions of thyristors and diodes are focused on. This paper points out that the resistance-capacitance circuit parameters, the current-limiting resistance and synchronization performance of triggers have significant impact on the operating condition of thyristors and diodes. It can be determined by the simulation results that excess high current-rising-rate has caused the damage of thyristor gate and large reverse voltage has resulted in the edge breakdown of diode. Finally, an optimization scheme of circuit parameters is put forward.