US8120224B2 – Permanent-magnet Switched-flux Machine – Google Patents

A second version of a CFG (CFG-2) has a structure different than the arrangement of interspersed north and south pole flux conductors of CFG-1. The major components of a CFG-2 include a rotor housing, an assembly of flux switches, a circular permanent-magnet with radial MMF orientation (e.g., north pole outside and south pole inside), a north laminate (e.g., an assembly of north pole tooth-like flux conductors, a stator coil, and a south laminate). In many applications (e.g., wind-turbine systems or vehicular drives), a high frequency-to-speed ratio is required to allow direct (e.g., gearless) mechanical connection between the generator and prime mover or the motor and load. Rotor 1 is driven by an external prime mover, e.g., a wind turbine, via shaft 7. In FIG.

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VOYOR Masajeador de cuello Shiatsu tejido profundo doble.. In certain embodiments of a single-phase PMSF device, magnetic flux can be produced by an even number of PMs attached to an inner surface of a tubular ferromagnetic rotor. In certain embodiments, the first and second pluralities of permanent-magnets each have permanent magnets of alternating polarity from one permanent-magnet to an adjacent permanent-magnet.

Dolor Muscular Piernas

Each of the two edges of a spool-shaped ferromagnetic stator, desirably mounted inside the rotor, is serrated into a number of stator poles p, which is equal to half of the number of PMs. The direction of flux changes p times per revolution of the rotor, so that the desired high frequency-to-speed ratio is desirably obtained. 1, it can be seen that an n-phase PMSF constitutes a stack of n single-phase PMSFs with the common shaft and stator (or rotor, in an inner-rotor case). 1, position of rotor 1 is such that the top stator poles 3 are aligned with those top magnets 5 that have the N-pole on the stator side, and the bottom stator poles 4 are aligned with those bottom magnets 6 that have the N-pole on the rotor side.

A PMSF machine with a coil 8, a non-ferromagnetic outer rotor 1 attached to a shaft 7, and permanent magnets 5 and 6 on a stator 2 having a stator core 9 is illustrated in FIGS. The fluxes desirably merge in the central core of the stator, around which the stator winding is arranged. Tens of flux conductors can be accommodated on the stator, so even a low rotor speed results in a high frequency and a high voltage EMF in the coil. When the rotor revolves around the stator, the stator poles, whose faces move close to the surfaces of the PMs, generally make low-reluctance paths for magnetic fluxes generated by the magnets.

Thus, in such a PMSF device, if one magnet has the N-pole on the side coupled to the rotor surface, the next magnet has the S-pole on the same side. AC generators, for example, typically have a permanent magnet that rotates inside a coil in such a way that the N-pole and S-pole alternate as seen from the coil. A CFG usually can be classified as an outer-rotor, single-coil, permanent-magnet, variable-reluctance generator, with an operating principle similar to that of flux-reversal machines. Dolor en brazo izquierdo y hormigueo en la mano . Yet another issue with CFG machines is their high cogging torque, which is typical of permanent-magnet single-phase machines generally. PM machines typically have high full-load efficiency, high output power per volume, high starting torque (in motors), and their maintenance is limited to periodic lubrication of the bearings. Consequently, TF motors often can run slowly, with a high torque, while a TF generator often can be driven by a slow prime mover, such as a wind turbine, still producing high output frequency.

Some exemplary single-phase PMSF devices can operate as alternating current (AC) generators, while some exemplary multi-phase PMSF devices can operate as either an AC generator or an AC motor. While a three-phase synchronous machine can work as both a generator and a motor, a single-phase machine can only work as a generator. In addition, because ideal conductors or insulators do not exist in any practical sense, only a fraction of the total flux generated in the PMs effectively links the armature winding, while the rest of the flux leaks elsewhere closing through other parts of the machine. Some PM machines have transverse flux (TF) paths, meaning that flux paths are parallel to the rotor axis and not perpendicular to the rotor axis as in classic synchronous machines. It is to be understood that all embodiments need not necessarily include all such features or provide all such advantages or address the issues noted in the background.

Dolores Musculares Y Fiebre

A motor with strong armature reaction and high leakage requires higher voltage to produce a given current and torque than that with weak armature reaction and low leakage. Curbing the phenomena of flux leakage and armature reaction has been particularly difficult in the design of PM synchronous AC machines. The armature reaction consists in the armature current producing its own magnetomotive force (MMF), which opposes the flux coming from the PMs. In such AC machines, current also flows in the armature winding, thereby producing the electromagnetic torque.