Electrical machine with double excitation, especially a motor vehicle alternator

An electrical machine, comprising:

• a stator defining at least one pair of stator slots, the stator slots defining between them a plurality of stator poles;
• a wire armature winding mounted in the stator slots;
• a rotor within the stator defining a plurality of rotor poles associated with the stator poles;
• a current adjustment circuit that provides unidirectional adjustable current;
• and
• permanent excitation magnets and excitation windings, said excitation windings coupled to said current adjustment circuit for selectively establishing closed magnetic circuits passing around the wires of the armature winding via the stator and rotor poles, the rotor poles defining a configuration consisting of alternate successive groups comprising a common odd number greater than one of identical north and south poles, and wherein, when current flows in the excitation windings, the rotor poles define a configuration comprising individual alternate north and south poles.

An electrical machine, comprising:

• a stator defining at least one pair of stator slots, the stator slots defining between them a plurality of stator poles;
• a wire armature winding mounted in the stator slots;
• a rotor within the stator defining a plurality of rotor poles associated with the stator poles;
• a current adjustment circuit that provides unidirectional adjustable current;
• and
• permanent excitation magnets and excitation windings, said excitation windings coupled to said current adjustment circuit for selectively establishing closed magnetic circuits passing around the wire of the armature winding via the stator and rotor poles, the rotor poles defining a configuration consisting alternatively of a given individual pole and a succession of opposite poles in an odd number greater than one, and wherein, when current flows in the excitation windings, the rotor poles define a configuration comprising individual alternate north and south poles.

A rotor, comprising:

• a plurality of circumferentially adjacent magnets;
• a plurality of poles between adjacent magnets extending outwardly in a radial direction, the spaces between the poles forming a plurality of slots;
• a current adjustment circuit that provides unidirectional adjustable current;
• and
• an excitation winding coupled to said current adjustment circuit in the slots adjacent to at least one of the plurality of poles between adjacent magnets, whereas when substantially none of said current flows through the excitation winding, a magnetic field generated by adjacent magnets induces the same polarity on poles between the adjacent magnets, and when more than a threshold level of said current flows through the excitation winding, a combined magnetic field generated by the adjacent magnets and the excitation winding between the adjacent magnets induces opposite polarities on adjacent poles between the adjacent magnets.

An electrical machine, comprising:

• a stator;
• a rotor containing a plurality of circumferentially adjacent magnets, the adjacent magnets separated by a plurality of poles;
• and
• means for selectively adjusting a unidirectional excitation current to induce either the same polarity on adjacent poles separating the adjacent magnets or opposite polarities on adjacent poles separating the adjacent magnets.