A Robustness Analysis of PPU Anode Power Supply To Hall-effect Thruster Flicker Phenomenon

This paper intends to describe the activity of PPU (Power Processing Unit) anode supply robustness verification when subjected to Hall-effect thruster (HET) flicker phenomenon. Flicker is an instability of the operating point that can sometimes impact HETs, where the oscillation amplitude of the discharge current significantly increases. The robustness is studied theoretically with worst-case assumptions and a simulation tool is used to verify the conditions where coupling between flicker and propellant flow controller's valve actuation occurs. Besides, a test campaign led in the frame of an Airbus Defence and Space (ADS) test campaign intended to validate a Plasma Propulsion Subsystem (PPS) product known as THruster Optimized and Reduced system (THORs) in 2019 provides data to consolidate the study. A custom electrical ground support equipment (EGSE) placed in parallel of the thruster's anode is intended to simulate the flicker phenomenon from the PPU point of view. During this campaign, two distinct 300 W-class thrusters were used along with two distinct propellant flow controllers. The goals of these tests were to check if flicker could provoke instability in the fluidic chain regulation. Theoretical analysis and simulations are detailed to explain the observed phenomena, and some measurements results are shown and commented.