US 12,323,012 B2
Electric machine
Seamus D Garvey, Nottingham (GB); and Karuna Kalita, Nottingham (GB)
Assigned to ROLLS-ROYCE PLC, London (GB)
Filed by ROLLS-ROYCE PLC, London (GB)
Filed on Feb. 28, 2024, as Appl. No. 18/589,701.
Claims priority of application No. 2303914 (GB), filed on Mar. 17, 2023.
Prior Publication US 2024/0313622 A1, Sep. 19, 2024
Int. Cl. H02K 11/30 (2016.01); F02C 6/20 (2006.01); F02C 7/268 (2006.01); H02K 1/14 (2006.01); H02K 7/18 (2006.01)
CPC H02K 11/30 (2016.01) [F02C 6/20 (2013.01); F02C 7/268 (2013.01); H02K 1/146 (2013.01); H02K 7/1823 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An electric machine comprising a stator, and a rotor configured to rotate relative to the stator, the stator having a phase arrangement, wherein:
the phase arrangement includes a first leg and a second leg connected in parallel at a first primary junction and a second primary junction;
the first leg includes a first-leg first coil and a first-leg second coil connected in series through a first intermediate junction;
the second leg includes a second-leg first coil and a second-leg second coil connected in series through a second intermediate junction, the first intermediate junction and the second intermediate junction being connected by a branch such that the phase arrangement is in the form of a bridge circuit;
the phase arrangement is configured to conduct, through each leg, a motor current through the respective in series coils between the first primary junction and the second primary junction;
the phase arrangement is configured to permit an alignment current to flow between the first primary junction and the second primary junction via the branch, the alignment current being conducted through an alignment current path which passes through one coil of each leg while bypassing at least one other coil of each leg;
the alignment current path has a positive electrical impedance provided by the coils of each leg;
the phase arrangement includes a negative impedance converter configured to add a negative electrical impedance to the alignment current path by introducing additional electrical energy into the alignment current path; and
the electric machine is configured so that:
the motor currents cause a torque to be applied to the rotor for rotation relative to the stator, and
the alignment current causes a translational force to be applied to the rotor, the translational force counteracting a force that acts on the rotor in a direction that would bring the rotor out of alignment with the stator, the translational force thereby maintaining alignment of the rotor with respect to the stator.