The European Direct-Drive Architecture (EDDA) project aims at optimizing the power chain efficiency of a spacecraft using electric propulsion, which is at the heart of technological roadmaps for future spacecraft. The objective is to develop, build and test a demonstrator of a high voltage and high power direct-drive concept. This innovative architecture supplies directly electric thrusters by a 300V-400V Solar Array without power conversion vs 28-100V in the current state of the art. The advantages are to remove power converters, to save mass, dissipation and cost, and to improve significantly the overall efficiency and reduce the thermal dissipation. In addition, at satellite level, it corresponds to a reduction of thrust duration, saving mission time. The ability of the concept to be applied to various thrusters technologies is key to maximize the impact of the architecture. Therefore this study is based on a transversal aspect of Electric Propulsion to be demonstrated on two different Electric Thruster technologies: Hall Effect Thruster (HET) from Sitael (Italy) and High Efficiency Multistage Plasma Thruster (HEMPT) from Thales-D (Germany). EDDA demonstration is based on a thruster plasma analysis (UC3M, Spain). Cathod Reference Point electronics, HET, vacuum chamber for complete testing are provided by Sitael. The bus voltage control loop and associated hardware are designed and manufactured by TAS-B. Coordination at satellite level is performed by TAS-F. Efficient Innovation provides effective management and associated tools. Tests will follow real operational conditions: no Sun, variation of illumination, thruster start-up and switch off, quick variation of consumption, and will demonstrate the robustness of this architecture easily adaptable to spacecraft (telecommunication satellites for Electric Orbit Raising reduction, In Orbit Servicing and Space-tugs, interplanetary carriers).