Abstract: To realize stable discharge of a Hall thruster operating in self-excited mode, a magnetic circuit and an electric circuit were designed to satisfy self-excited operation requirements. Based on optimized operation performance parameters in separate-excited mode and keeping magnetomotive force constant, FEMM-finite element method magnetics software was used to create the magnetic circuit model. The magnetic field which satisfied the requirements of discharge in self-excited mode was obtained by reducing the radius of inner core from 7mm to 4mm. Considering the coils insulating requirements,all serial coils were inserted into negative pole of discharge power supply. This electric circuit made the discharge more reliable. The experimental results indicated that the performance parameters in self-excited mode were close to the ones in separate-excited mode. The maximum thrust efficiency reached 61% at discharge voltage of 420V. Stable discharge is obtained in self-excited mode experiments and the amplitude of low frequency oscillation of discharge current is small.

Key words: Hall thruster; Self-excited mode; Magnetic circuit design; Electric circuit design

摘要： 为实现P70霍尔推力器自励模式稳定放电运行,分别设计了满足自励模式放电要求的磁路和电路。其磁路设计是基于霍尔推力器他励运行模式最优放电性能参数和磁势不变原理,采用FEMM有限元磁场计算软件建模,将推力器内铁心半径由7 mm减至4 mm,可得到满足自励模式运行要求的优化磁场。针对电磁线圈串入主放电回路不同位置对放电的影响,考虑电磁线圈绝缘要求,提出将电磁线圈串入放电电源负极性端,整体电路设计可使放电可靠。性能对比实验表明,自励模式与他励模式性能接近,在放电电压为420V时,自励模式最高效率达到61%。自励模式实验获得了稳定放电,且放电电流低频振荡幅值很小。

关键词: 霍尔推力器;自励模式;磁路设计;电路设计