The Multiphase Thermoelectric Converter is a direct thermal-to-electrical energy conversion system designed in order to harvest most of the waste heat energy efficiently into electricity, reducing weight and size of space heat radiators, making fusion-powered space propulsion more energy-efficient than ever. The Multiphase Thermoelectric Converter consists of two opposing twisting electromagnetic forces, forming two contra-aligned electrodynamic vortices, for axially and radially compressing a hot ionized gas F=q(v × B) forcing it to expand longitudinally transferring electrodynamically F=i(L × B) ε=(Bℓv sinθ) its energy to a multiphase electrical system to be effectively harvested by diode rectifiers. Wherein, the phase rotation keeps hot plasma centered far from electromagnetic coils, which allow to induce high pressure and withstand very high temperatures for virtually getting closer to the maximum efficiency η=1-(TC/TH), e.g. TC=300K, TH=30000K, η%=99%. Together with the Aneutronic Reactor and Electrodynamic Thrusters, it is to form the most perfect triad for providing a high degree of cleanliness and efficiency for deep space propulsion, with practically no thermal and radioactive waste.