Synchronous motor
Synchronous motors present zero slip. They are the ones manufacturers are now facing: with better torque / weight ratios and power density and higher yields, they are divided into two categories: coils and permanent magnets.
While the coils have a magnetic rotor with currents, the permanent magnet synchronous motors do not need rotor coils. They are therefore lighter and have no longer joule losses to the rotor, the losses to the stator being easy to evacuate.
The latter type of engine may therefore seem superior, but since permanent magnets are, like many rare earths, a material whose supply depends very much on the conditions of economic exchange with China, it is necessary to discuss between the performance of the engine and the volatility of its price ...
While PSA and Toyota are moving towards this technology with respectively Ion and Prius, Renault-Nissan and Bolloré prefer the wound rotor.
https://www.industrie-techno.com/les-se ... ques.42249