摘要:
Rotary permanent magnet motors have salient stator poles with nonuniform pole thickness in the radial direction for compensating effects of cogging torque. Pole base portions terminate at pole shoes at the radial air gap. The pole shoes extend in the circumferential direction from the bulkier base portions. Variation of the thickness of the pole shoe changes the concentration of the effective flux at the point of coupling between the stator poles and the permanent magnet pole shoes. As there is no change in the active interfacing area of the pole shoes a uniform air gap is maintained. The torque signature for each stator pole/rotor permanent magnet interface can be selectively changed to smooth motor operation by configuring the stator pole shoe thickness to vary along its circumferential extent as appropriate. Pole shoes may have tapered leading or trailing edges with respect to a pole base to change the effective flux density in the air gap at a specific pitch of rotation. Additionally, the pole shoe may be shifted off center with respect to the pole base.
摘要:
A permanent magnet motor includes salient pole stator cores. The poles and/or linking portions therebetween are wound with a plurality of winding coil sets. Mutually exclusive speed ranges are established between startup and a maximum speed at which the motor can be expected to operate. A different number of the motor stator winding coils are designated to be energized for each speed range for maximum operating efficiency. The number of energized coils are changed dynamically as the speed crosses a threshold between adjacent speed ranges.
摘要:
A permanent magnet motor is configured with selective variation of the radial distance between an interfacing pair of rotor permanent magnet and stator pole along the circumferential length of the pair. The effects of cogging torque on the overall torque signature can be controlled by setting an appropriate air gap variation profile. The stator pole and rotor magnet surfaces may be sloped with respect to each other, the angle therebetween being selected to obtain desired cogging torque compensation. Other air gap variation profiles may include provision of concave surfaces, the degree of concavity being selectable.
摘要:
A rotary electric motor has a stator with a plurality of axially spaced sets of corresponding stator and rotor elements. The stator of each set is an annular ring with poles circumferentially positioned about an axis of rotation. The rotor of each set has a plurality of permanent magnets disposed circumferentially along an annular air gap opposite the stator poles. The permanent magnets of adjacent rotor element sets and/or the poles of adjacent stator sets are offset from each other in the axial direction to cancel the effects of cogging torque produce by each of the sets.
摘要:
A rotary brushless electric motor is formed within a cylindrical rotor housing structure that surrounds an annular stator ring. The stator is formed of a plurality of individual power modules and corresponding core segments, each module including electrical control and drive elements supplied by a power source incorporated within the stator. Such parallel architecture provides relatively independently controlled functionality for each module. Each module and stator core segment can be individually installed and removed without disturbing the other units. Should a particular module or stator core segment fail, it can be easily removed for repair or replacement and reinstallation.
摘要:
In a rotary electric motor, a stator contains a plurality of separate electromagnet core segments disposed coaxially about an axis of rotation. The core segments are affixed, without ferromagnetic contact with each other, to a non-ferromagnetic support structure. The rotor is configured in a U-shaped annular ring that at least partially surrounds the annular stator to define two parallel axial air gaps between the rotor and stator respectively on opposite axial sides of the stator and at least one radial air gap. Permanent magnets are distributed on each inner surface of the U-shaped rotor annular ring that faces an air gap. A winding is formed on a core portion that links axially aligned stator poles to produce, when energized, magnetic poles of opposite polarity at the pole faces.
摘要:
A control system for a multiphase permanent magnet motor compensates for physical variations among individual motor phase circuit elements. The control system successively develops a control voltage for switched energization of the motor phase windings that is closely matched with particular parameters of the corresponding windings. The system can be applied to a motor in which each stator phase component comprises a ferromagnetically isolated stator electromagnet, the electromagnet core elements being separated from direct contact with each other and formed with separate phase windings. A digital signal processor may be utilized that applies an algorithm incorporating the parameters as constant values, the parameters for a particular phase being accessed for generating the appropriate control signals for energizing that phase.
摘要:
A rotary electric motor has a stator with a plurality of separate and ferromagnetically isolated electromagnet core segments disposed coaxially about an axis of rotation. The core segments are supported by a non-ferromagnetic structure. Each core segment has at least three poles aligned in a direction parallel to the axis. Windings are formed on portions linking the poles so that, when energized, the center pole forms a magnetic polarity opposite to the magnetic polarity of the other poles. The rotor comprises a plurality of axial rows of permanent magnets disposed circumferentially along the air gap. Each axial row of rotor magnets comprises a center permanent magnet of one magnetic polarity and, at each axial side thereof, a permanent magnet of a magnetic polarity opposite to the polarity of the center magnet.
摘要:
A rotary electric motor comprises a rotor having a plurality of permanent magnet elements disposed in an annular ring configuration about an axis of rotation, the magnet elements successively alternating in magnetic polarity along an inner annular surface, and a stator spaced from the rotor by a radial air gap. The stator includes a plurality of magnetic core segments having respective coils wound thereon to form stator windings, the core segments separated from direct contact with each other and disposed along the radial air gap. Each stator segment comprises a pair of poles aligned with each other in a direction parallel to the axis of rotation. Thus the stator comprises a first set of stator poles in radial alignment and an axially displaced second set of stator poles in radial alignment.
摘要:
A permanent magnet motor has rotor structure that includes magnetically permeable backing material attached to magnets for enhancing flux density distribution. A plurality of permanent magnets are circumferentially distributed about an axis of rotation, adjacent magnets successively alternating in magnetic polarity. The magnetically permeable material is configured with apertures therethrough at areas of low flux density, such as at central portions of the magnets, while in contact with perimeter areas of the magnets. Additional apertures in the material may be located at spaced intersections at which no significant flux density exists. The apertures may be replaced with backing material portions of reduced radial thickness.