An electric drive comprises a bearingless electric machine, a converter, and a control device. The stator of the electric machine has a cage winding including bars connected to a conductor ring. The control device controls the converter to supply torque generating current components to the bars so that torque is generated in accordance with electric machine control and to supply levitation current components to the bars so that the rotor of the bearingless electric machine is levitated in accordance with levitation control. The cage winding allows the currents of the bars to be controlled so that different current sheet distributions can be generated so as to generate desired torque and magnetic force.

An electric drive comprises a bearingless electric machine, a converter, and a control device. The stator of the electric machine has a cage winding including bars connected to a conductor ring. The control device controls the converter to supply torque generating current components to the bars so that torque is generated in accordance with electric machine control and to supply levitation current components to the bars so that the rotor of the bearingless electric machine is levitated in accordance with levitation control. The cage winding allows the currents of the bars to be controlled so that different current sheet distributions can be generated so as to generate desired torque and magnetic force.

A synchronous electrical motor, which may operate poly-phase electrical power, is configured to operate at a rated flux configuration and a high flux configuration. To enable the high flux configuration, some coils wound about the stator of the electric motor can be designated bypass coils and can be selectively disconnected from the power source supplying the motor with electrical power. The remaining permanent coils continue to receive full line power and generate a rotating magnetic field with an increased magnetic flux. At startup from standstill conditions, the bypass coils are selectively disconnected so that a flux boost occurs and a corresponding increase in output torque of the electric motor.

The present invention relates to a line start synchronous reluctance motor and a rotor thereof. To this end, the present invention provides a line start synchronous reluctance motor including: a rotor; a plurality of conductor bars disposed on a side of an outer circumferential portion of the rotor; and flux barriers formed at an inner side of the rotor so as to be close to the conductor bars, wherein the flux barriers, which are formed in separate regions of a body of the rotor that are arranged to have opposite polarities, are formed to be asymmetrical to each other. Therefore, the present invention improves characteristics of the motor through the asymmetrical flux-barrier structure without changing the number of conductor bars, thereby allowing the initial starting of the motor to be smoothly performed, which is advantageous in terms of torque ripple characteristics and die casting.

The present invention relates to a line start synchronous reluctance motor and a rotor thereof. To this end, the present invention provides a line start synchronous reluctance motor including: a rotor; a plurality of conductor bars disposed on a side of an outer circumferential portion of the rotor; and flux barriers formed at an inner side of the rotor so as to be close to the conductor bars, wherein the flux barriers, which are formed in separate regions of a body of the rotor that are arranged to have opposite polarities, are formed to be asymmetrical to each other. Therefore, the present invention improves characteristics of the motor through the asymmetrical flux-barrier structure without changing the number of conductor bars, thereby allowing the initial starting of the motor to be smoothly performed, which is advantageous in terms of torque ripple characteristics and die casting.

A hybrid induction motor includes a fixed stator, an independently rotating first rotor, and a second rotor fixed to a motor shaft. The first rotor is designed to have a low moment of inertia and includes an inductive element which is either an eddy current ring or angularly spaced apart first bars, and also includes permanent magnets on a surface of the first rotor facing the second rotor. The second rotor includes angularly spaced apart second bars. The first rotor is initially accelerated by cooperation of a rotating stator magnetic field with the inductive element. As the first rotor accelerates towards synchronous RPM, a rotating magnetic field of the permanent magnets cooperate with the second bars of the second rotor to accelerate the second rotor. At near synchronous speed the rotating stator magnetic field reaches through the first rotor and into the second rotor coupling the two rotors for efficient permanent magnet operation.

A hybrid induction motor includes a fixed stator, an independently rotating first rotor, and a second rotor fixed to a motor shaft. The first rotor is designed to have a low moment of inertia and includes an inductive element which is either an eddy current ring or angularly spaced apart first bars, and also includes permanent magnets on a surface of the first rotor facing the second rotor. The second rotor includes angularly spaced apart second bars. The first rotor is initially accelerated by cooperation of a rotating stator magnetic field with the inductive element. As the first rotor accelerates towards synchronous RPM, a rotating magnetic field of the permanent magnets cooperate with the second bars of the second rotor to accelerate the second rotor. At near synchronous speed the rotating stator magnetic field reaches through the first rotor and into the second rotor coupling the two rotors for efficient permanent magnet operation.

A rotor includes a rotor core that is made of electromagnetic steel sheets rotating around a central axis and laminated in an axial direction, and that has multiple flux barriers penetrating the electromagnetic steel sheets along the axial direction. At least some of the multiple flux barriers are provided with a first penetrating portion and a second penetrating portion arranged in the radial direction, the first penetrating portion housing a magnet and the second penetrating portion housing a conductive non-magnetic conductor.

A hybrid induction motor includes a fixed stator, an independently rotating outer rotor, and an inner rotor fixed to a motor shaft. The outer rotor is designed to have a low moment of inertia and includes angularly spaced apart first bars and permanent magnets on an inner surface of the outer rotor. The inner rotor includes angularly spaced apart second bars and interior flux barriers aligned with the second bars. The outer rotor is initially accelerated by cooperation of a rotating stator magnetic field with the first bars. As the outer rotor accelerates towards synchronous RPM, a rotating magnetic field of the permanent magnets cooperate with the second bars of the inner rotor to accelerate the inner rotor. At near synchronous speed the rotating stator magnetic field reaches through the outer rotor and into the inner rotor coupling the two rotors for efficient permanent magnet operation.

A hybrid induction motor includes a fixed stator, an independently rotating outer rotor, and an inner rotor fixed to a motor shaft. The outer rotor is designed to have a low moment of inertia and includes angularly spaced apart first bars and permanent magnets on an inner surface of the outer rotor. The inner rotor includes angularly spaced apart second bars and interior flux barriers aligned with the second bars. The outer rotor is initially accelerated by cooperation of a rotating stator magnetic field with the first bars. As the outer rotor accelerates towards synchronous RPM, a rotating magnetic field of the permanent magnets cooperate with the second bars of the inner rotor to accelerate the inner rotor. At near synchronous speed the rotating stator magnetic field reaches through the outer rotor and into the inner rotor coupling the two rotors for efficient permanent magnet operation.