Characterization of a high-power Hall thruster operation in direct-drive. (January 2021)

• Record Type: Journal Article
• Authors: Reza, Maryam; Faraji, Farbod; Andreussi, Tommaso
• Is Part Of: Acta astronautica. Volume 178(2021)
• Page Start: 392
• Page End: 405
• Publication Date: 2021-01
• Subjects: Direct drive -- Power processing unit -- Solar array simulator -- Hall thruster -- Grounding; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2020.09.008
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: In Hall propulsion systems, a direct and non-isolated connection between the thruster discharge and the solar array implies a significant change in terms of spacecraft grounding, thruster operation and control. In this so-called direct-drive architecture, since discharge voltage and current are no more fixed by a power processing unit but are constrained by the solar array characteristic, which changes during a space mission, specific control laws need to be developed and tested to assess the feasibility of thruster operation. In this paper, in-depth investigations performed in SITAEL on thruster performance and operation controllability of a direct-drive Hall thruster system are presented. The HT5k, a 5 kW-class Hall thruster, was connected to a solar array simulator (SAS) and tested at different operating conditions. Three different thruster control laws were implemented and were proved effective in controlling the thruster behavior with respect to on-orbit-representative variations in the SAS characteristics. The results also highlighted minimal difference between thruster performance parameters in direct-drive and with a conventional power supply. Finally, the impact of grounding on thruster plume interaction with the spacecraft was analyzed. Highlights: Direct drive is a viable alternative to electric propulsion power processing units. A long-life Hall thruster with novel magnetic field topology tested in direct drive. Thruster ignition and operation along several solar array curves showed no issues. Thruster control using different logics including peak power tracking of IV curves. Direct drive effects on system grounding and methods to reduce parasitic currents.