In a relentless desire to continuously improve the performance of electric actuators, “non-parametric” optimal design approaches present interesting possibilities. In particular, these works apply the optimization method by material distribution in order to define internal configurations (here rotor) of material arrangements (air, iron, copper and magnet) potentially new and giving the best performance to the machine. This approach is applied here in several design confi gurations of magnet-free synchronous machine rotors.