PPU Optimizations for a Low Power EPS

The Microsatellite Electric Propulsion System (MEPS) program has been originated by the increasing need to provide a low cost and low power Electric Propulsion System (EPS) for small satellites (<300Kg). The propulsion system of MEPS consists of three main parts, the Thruster Units (TUs) composed of a Hall Effect Thruster (Rafael's CAM-200 or SITAEL's HT100) and a Cathode (Rafael's Heaterless Hollow Cathode RHHC), the Propellant Management and Tank Assembly (PMA/PTA) which performs the regulation of xenon mass flow rate from the tank to the TU inlet, and the Power Processing Unit (PPU) which provides the necessary power to drive the TUs and the PMA/PTA and implements the system control logic. The objective of this paper is to present the development status of MEPS PPU highlighting the design optimizations and simplifications that have been performed. Particular emphasis is aimed at the most indicative improvements and how all modifications contributed to the PPU budget in terms of number of components, mass, size and cost, without affecting system efficiency, performance and reliability. Aggregated results for PPU budget are thoroughly illustrated, by taking into account the overall optimizations and simplifications. The results are very promising and point to a reduction on overall number of components, mass, area and cost in the range of 15% - 33%, all very significant especially in space market.