Electric machine with an electromagnetic bearing

An electric machine provided with an electromagnetic bearing, the electric machine comprising:

• a rotor from which a magnetic field emanates;
• a stator adapted to produce a magnetic field that interacts with the magnetic field emanating from the rotor, the stator comprising a pair of windings symmetrically positioned with respect to the rotor so that a displacement of the rotor causes an increase in magnitude of a magnetic flux induced by the rotor in one winding of the pair of windings and a decrease in magnitude of a magnetic flux induced by the rotor in the other winding of the pair of windings;
• and
• a driver adapted to operate in an active electromagnetic bearing mode in which the driver applies a suspension signal component to at least one winding of the pair of windings, which causes the magnetic field produced by the stator to have a component that exerts a suspension force on the rotor through interaction with the magnetic field emanating from the rotor,
• wherein the driver comprises a controller configured to make the driver operate in a passive electromagnetic bearing mode instead of in the active electromagnetic bearing mode depending on at least one operational condition of the electric machine, whereby, in the passive electromagnetic bearing mode, the driver interconnects the pair of windings of the stator with each other so that the increase in magnitude of the magnetic flux in the one winding and the decrease in magnitude the other winding of the pair of windings generates a suspension current in the pair of windings that causes the magnetic field produced by the stator to have a component that exerts a restoring force on the rotor counteracting the displacement.