Unexpected Electrical Breakdown Characteristics and Protection of PPU in Space Electric Propulsion System

Abstract

Abstract The application of fully electric propulsion satellites will increase the risk of low-pressure discharge in electric propulsion devices, especially ion thrusters, whose unexpected breakdown will directly affect the reliability of satellite applications. Existing on-orbit cases show that the unexpected breakdown occurred in the power processing unit (PPU) of the ion thruster during orbit change, which led to the failure of thruster. Therefore, this paper analyses the high-voltage components inside the PPU, and systematically discusses the PPU and its working environment, the control and protection technology of unexpected electrical breakdown of the electric propulsion system and its aerospace engineering. In this paper, we discuss the electric field intensity and discharge margin of components in the PPU under different conditions, and further propose a method for insulation evaluation based on partial discharge (PD) detection. The research results show that the discharge margin in the PPU is close to the lowest discharge voltage level of uniform electric field, so reasonable insulation protection measures should be taken against discharge under high voltage condition. Furthermore, we propose a feasibility analysis method based on PD insulation defect detection, which provides a basis for quantitative analysis and evaluation of component insulation design in PPU systems.