Synchronous electric machine with two rotors

Synchronous electric machine comprising: - a stator (12) including a plurality of teeth (18) arranged at equal angular intervals and having first and second active surfaces (20, 22), - a first stator winding (24) having a series of first coils (28) wound on said teeth (18), - a second stator winding (26) having a series of second coils (30) wound on said teeth (18), - a first rotor (14) having a series of first permanent magnets (32) arranged at equal angular intervals with alternate polarities and facing said first active surfaces (20), - a second rotor (16) having a series of second permanent magnets (34) arranged at equal angular intervals with alternate polarities and facing said second active surfaces (22), wherein the first and the second rotors (14, 16) are supported in rotation, independently of each other, around a common axis (A), wherein the first coils (28) and the second coils (30) of each stator winding (24, 26) are arranged in pairs, with the two coils (28 i ', 28 i "; 30 i ', 30 i ") of each pair offset from each other by a predetermined angle, wherein, during operation as a motor, the two first coils (28 i ', 28 i ") of each pair produce concordant torque contributions on the first rotor (14) and discordant torque contributions on the second rotor (16) and the two second coils (30 i ', 30 i ") of each pair produce concordant torque contributions on the second rotor (16) and discordant torque contributions on the first rotor (14).