Abstract: In order to improve the life and reliability when igniting the pulsed plasma thrusters，a power processing unit of discharging energy 2.6J applied for microsatellites pulsed plasma electric propulsion system was designed by using theoretical calculation and ground test methods，its’ discharge initiation pulse circuit was based on a LC resonant tank circuit. The performance of discharge initiation pulse circuit and the current stress of the switch，as well as the stable reliability of the whole power processing unit were studied. The results show the current stress of the switch is smaller in the LC resonant tank circuit，improving the reliability of the whole circuit. Besides，the peak value of ignition current can reach 100A～150A when the input voltage of this discharge initiation pulse circuit is 800V. This high current discharge contributes to clearing the carbon deposition on the surface of the spark plug.

Key words: Pulsed plasma thruster;Electric propulsion system;Power processing unit;Discharge initiation pulse circuit;LC resonant tank circuit

摘要： 为了进一步提高脉冲等离子体推力器点火的可靠性和使用寿命，采用理论计算和地面试验的方法，设计了一款可应用于立方体纳卫星脉冲等离子体推力器放电能量为2.6J的电源处理单元，其放电点火电路是基于LC振荡电路，且对放电点火电路的性能、开关管的电流应力和整个电源处理单元的稳定可靠性进行了研究。结果表明：LC振荡放电点火电路中，开关器件的电流应力较小，提高了整个电路的可靠性；该放电点火电路在输入电压800V时，点火电流的峰值可达到100A～150A，这种大电流放电有助于清除火花塞表面的积碳。

关键词: 脉冲等离子体推力器;电推进系统;电源处理单元;放电点火电路;LC振荡电路