The invention relates to electromechanical assemblies comprising an alternator, especially of high power, typically greater than or equal to IMW, and a converter, the alternator comprising a rotor driven in rotation, by a wind turbine for example, and more particularly to wound rotor synchronous alternators. The drive can also take place by means of a tide-driven, hydraulic or marine-current-driven generator. An alternator comprises in a manner known per se a field winding, generally at the rotor, supplied with DC current either by split rings and brushes, or by an exciter, so as to generate in an armature winding, generally at the stator, an AC voltage.