Electric machine with single stator and two mutually independent rotors, and road vehicle provided with said electric machine

An electric machine, comprising:

• a stator provided with one single stator winding;
• at least two shafts which are independent from one another and mounted rotating;
• at least two rotors which are independent from one another, magnetically coupled to the stator and mounted on the shafts;
• a first rotor presents a first number of pole pairs and a second rotor presents a second number of pole pairs, which is different from the first number of pole pairs;
• and
• a single electronic power converter which is connected to the stator winding in order to supply the stator winding itself through a total electric current;
• the stator winding when it is crossed by a first system of sinusoidal electric currents generates a first rotating magnetic field presenting a very important harmonic of order equal to the first number of pole pairs and negligible harmonics of order equal to the second number of pole pairs or a multiple thereof, and when it is crossed by a second system of sinusoidal electric currents generates a second rotating magnetic field presenting a very important harmonic of order equal to the second number of pole pairs and negligible harmonics of order equal to the first number of pole pairs or a multiple thereof;
• and
• the electronic power converter generates a total system of electric currents which flows through the stator winding and is made up by the union of a first system of sinusoidal electric currents generating a first rotating magnetic field presenting a very important harmonic of order equal to the first number of pole pairs and negligible harmonics of order equal to the second number of pole pairs or a multiple thereof and of a second system of sinusoidal electric currents generating a second rotating magnetic field presenting a very important harmonic of order equal to the second number of pole pairs and negligible harmonics of order equal to the first number of pole pairs or a multiple thereof;
• wherein both rotors are provided with permanent magnets;
• wherein the stator winding presents a fractional number of slots per pole and per phase with both rotors;
• wherein the stator winding presents an odd number of phases which is equal to the double of the number of rotors added by one;
• wherein the first system of sinusoidal electric currents and the second system of sinusoidal electric currents have the same number of phases which is equal to the number of phases of the stator winding;
• and
• wherein the delay angle existing between the current of one phase and the current of the successive phase of the first system of sinusoidal electric currents is different from the delay angle existing between the current of one phase and the current of the successive phase of the second system of sinusoidal electric currents.