Permanent-magnet-less machine having an enclosed air gap
A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).
1. A permanent magnet-less, brushless synchronous system comprising:
a stator that generates a magnetic rotating field when sourced by an alternating current;
an uncluttered rotor disposed within the magnetic rotating field and spaced apart from the stator to form an air gap relative to an axis of rotation; and
a stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap,
where the uncluttered rotor comprises a plurality of rotor pole stacks configured to have quadrature flux paths, the flux paths being partially bounded by dielectric channels passing through each of the plurality of rotor pole stacks, and
where the stator comprises a plurality of teeth juxtaposed in an axial direction, the teeth including a return path for interconnecting the teeth to a plurality of alternating phases.
2. The permanent magnet-less, brushless synchronous system of claim 1 where the axial air gap and radial air gap comprise a substantially bilateral symmetrical area.
3. The permanent magnet-less, brushless synchronous system of claim 2 where each of the rotor stacks comprises a plurality of thin bridges that mechanically link the poles of the rotor.
4. The permanent magnet-less, brushless synchronous system of claim 2 where the uncluttered rotor comprises stacked laminations configured to facilitate the quadrature flux paths and direct axis flux paths.
5. The permanent magnet-less, brushless synchronous system of claim 4 where the flux flowing in the quadrature flux paths converge by the dielectric channels passing through the plurality of rotor pole stacks.
6. The permanent magnet-less, brushless synchronous system of claim 1 where the uncluttered rotor comprises a plurality of rotor pole portions and each rotor pole couples a lamination stack.
7. The permanent magnet-less, brushless synchronous system of claim 6 where an outer periphery of the uncluttered rotor lacks a narrow bridge.
8. The permanent magnet-less, brushless synchronous system of claim 1 , wherein the stator further comprises a plurality of stator cores separated by a blocking stator core gap.
9. The permanent magnet-less, brushless synchronous system of claim 8 where the blocking stator core gap is filled with a non-magnetic insulation.
10. A permanent magnet-less, brushless synchronous system comprising:
a stator that generates a magnetic rotating field when sourced by an alternating current;
an excitation core that comprises two or more magnetically conducting coils positioned apart from the stator; and
an uncluttered rotor disposed within the magnetic rotating field and spaced apart from the excitation core by a continuous air gap that surrounds the excitation core;
where the stator comprises a wound core,
and
where the uncluttered rotor comprises a plurality of teeth and the stator further comprises a blocking element that substantially blocks an axial flux flow through the stator.
11. The permanent magnet-less, brushless synchronous system of claim 10 where the excitation core is axially disposed about a hollow substantially cylindrical channel axially coincident with a rotatable shaft.
12. The permanent magnet-less, brushless synchronous system of claim 11 where the hollow substantially cylindrical channel comprises a stationary channel that includes an inlet and an outlet.
13. The permanent magnet-less, brushless synchronous system of claim 10 where the uncluttered rotor couples a plurality of laminations that form discontinuous stacks having ferromagnetic properties.
14. The permanent magnet-less, brushless synchronous system of claim 13 where the plurality of rotor pole stacks comprises stacked laminations configured to form the quadrature flux paths when the stator is sourced by an alternating current, and the stator is separated centrally by a separate dielectric channel that resists flux flow.