Discrete Cathode Power Supplies for Low Power Hall Effect Thrusters

Abstract

The Hollow Cathode is essential in determining the performance and reliability of the Hall Effect Thruster (HET) and is one of the main lifetime-limiting factors. Being such a critical element for the operation of the Thruster, the required Cathode Power Supply (CAPS) is playing an important role and constitutes a challenge from the power electronics design point of view, since a well-defined and demanding ignition procedure is required to succeed repeatable results alongside with proper isolation requirements. The Microsatellite Electric Propulsion System (MEPS) program aims at the qualification of an electric propulsion system based on a low power (up to 300 W) HET, embodying Rafael's Heaterless Hollow Cathode (RHHC) along with two types of Thruster Units (TUs) (SITAEL's HT100 and Rafael's CAM-200). In the frame of this program the required CAPS has been designed for the Elegant Bread Board (EBB) of the Power Processing Unit (PPU) as two discrete modules; 500 Vmax isolated current driven (settable up to 0.5 A) keeper power supply and 800 V isolated High Voltage (HV) igniter. The objective of this paper is to present the CAPS EBB modules design by showing the preliminary results obtained after a series of coupling tests of CAPS at Breadboard (BB) level with multiple configurations on which the EBB design was also based. Since RHHC has a wide operational range, the current EBB design along with the future progress of the program with the manufacturing and testing of the CAPS can become the driving factor for the successful implementation of an easily adjustable CAPS compatible with a wide range of Hollow Cathodes enabling the ignition of several low power HETs. In this direction, the feasibility for the already designed CAPS to drive also a different type of low power TU composed of a HET and a Heated Cathode (SITAEL's HC1) with minor modifications was investigated and a preliminary evaluation is presented.