Electric machine

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.