Electric machine

1. An electric machine, comprising:

a stator including an armature winding;

a first rotor; and

a second rotor configured to allow a magnetic path to be created between the stator and the first rotor,

the armature winding being a concentrated winding armature winding,

the second rotor having a plurality of circumferentially spaced bars of soft magnetic material,

the first rotor having a plurality of salient poles, which are arranged side by side in the circumferential direction, wound by induction coils and field coils and a rectifier circuit configured to rectify induced current generated by each of induction coils to DC current;

wherein the induction coils are arranged between the second rotor and the field coils in a radial direction relative to an axis of rotation of the first and second rotors,

wherein the rectifier circuit includes a plurality of rectifier elements, the induction coils are arranged in plural groups each connected to an upstream side of the plurality of rectifier elements such that any one of and another one of the induction coils of a same group generate induced currents that have substantially overlapped current waveforms, and the field coils are connected to a downstream side of each of the plurality of rectifier elements, and

wherein the induction coils in each group are connected in series on the upstream side of the corresponding one of the plurality of rectifier elements.

2. The electric machine as recited in claim 1 , wherein the induction coils are grouped into a plurality groups and connected in series in each group such that the range where waveform of induced current is inversed-phase is minimized in each group.

3. The electric machine as recited in claim 1 , wherein the induction coils are grouped and arranged in an identical sequence pattern in the circumferential direction of the first rotor.

4. The electric machine as recited in claim 1 , wherein each respective salient pole is wound by one of the induction coils and one of the field coils.

5. The electric machine as recited in claim 4 , wherein the field coils wrapped around two adjacent salient poles are wound in mutually reversed winding directions.

6. The electric machine as recited in claim 4 , wherein one of the field coils, wound around a respective salient pole, is longer than one of the induction coils, wound around the respective salient pole, in the radial direction.

7. The electric machine as recited in claim 1 , wherein the stator is formed with a plurality of stator teeth, and the stator teeth are wound by armature winding with concentrated winding wrapped around outer periphery sides of the stator teeth; and

wherein each stator tooth is wider than the salient pole in the circumferential direction.