New High Power / High Voltage Battery-Free Bus for Electrical Propulsion in Satellites

In this paper a solution for the power conditioning and distribution unit (PCDU) of the solar electric propulsion module (SEPM) is proposed. The electronic propulsion system is made out of ion thrusters which need a very steady supply voltage and therefore care has to be taken during switch off of the ion thrusters (beam-out) to avoid transient overvoltages (they must be less than 2%). The new conception is a new sequential switching shunt maximum power regulator (S3MPR) consisting in a sequential switching shunt regulator (S3R), to keep the SA voltage at its maximum power point (MPP) followed by a boost regulator to produce a constant 100 V to supply the electronic propulsion (EP). The PCU has been verified by means of testing on a scaled-down Power Subsystem of 1 kW output power.