Stator coil arrangement for an axial airgap electric device including low-loss materials
A dynamoelectric, rotating electric machine includes a stator assembly that includes stacked stator coil windings. The machine is preferably a polyphase, axial airgap device. Improved slot filling results from the stacked stator coil configuration. Device performance capability is thereby increased. The stator assembly of the electric device has a magnetic core made from low loss, high frequency material. A high pole count permits the electrical device to operate at high commutating frequencies, with high efficiency, high power density and improved performance characteristics. Low-loss materials incorporated by the device include amorphous metals, nanocrystalline metals, optimized Si—Fe alloys, grain-oriented Fe-based materials or non-grain-oriented Fe-based materials.
1. An axial airgap, polyphase dynamoelectric machine, comprising:
(a) at least one stator assembly comprising a backiron section and a plurality of tooth sections, said stator assembly having a slot having a slot width between each adjacent pair of said tooth sections and two stacked stator phase windings present in each of said slots, each winding encircling one or more of said tooth sections and occupying substantially the full available slot width; and
(b) at least one rotor assembly supported for rotation about an axis and including a plurality of rotor poles, said rotor assembly being arranged and disposed for magnetic interaction with said at least one stator assembly, and
wherein said stator assembly comprises low core loss magnetic material characterized by a core loss less than “L” when operated at an excitation frequency “f” to a peak induction level “B max ” wherein L is given by the formula L=12·f·B 1.5 +30·f 2.3 ·B 2.3 , the core loss, excitation frequency and peak induction level being measured in watts per kilogram, kilohertz, and teslas, respectively.
2. A method for constructing an axial airgap, polyphase dynamoelectric machine, comprising:
(a) providing at least one stator assembly comprising a backiron section and a plurality of tooth sections, said stator assembly having a slot having a slot width between each adjacent pair of said tooth sections and two stacked stator phase windings present in each of said slots, said windings consisting of equal numbers of up-coils and down-coils, each of said up-coils being connected in series with one of said down-coils, and each winding encircling one or more of said tooth sections and occupying substantially the full available slot width; and
(b) providing at least one rotor assembly supported for rotation about an axis and including a plurality of rotor poles, said rotor assembly being arranged and disposed for magnetic interaction with said at least one stator assembly,
wherein said stator assembly comprises low core loss magnetic material characterized by a core loss less than “L” when operated at an excitation frequency “f” to a peak induction level “B max ” wherein L is given by the formula L=12·f·B 1.5 +30·f 2.3 ·B 2.3 , the core loss, excitation frequency and peak induction level being measured in watts per kilogram, kilohertz, and teslas, respectively.
3. An axial airgap, dynamoelectric machine, comprising:
(a) at least one stator assembly comprising a backiron section and a plurality of tooth sections, said stator assembly having a slot having a slot width between each adjacent pair of said tooth sections and a plurality of stacked stator phase windings, each winding encircling one or more of said tooth sections and occupying substantially the full available slot width, and said stator assembly comprising low core loss magnetic material characterized by a core loss less than “L” when operated at an excitation frequency “f” to a peak induction level “B max ” wherein L is given by the formula L=12·f·B 1.5 +30·f 2.3 ·B 2.3 , the core loss, excitation frequency and peak induction level being measured in watts per kilogram, kilohertz, and teslas, respectively; and
(b) at least one rotor assembly supported for rotation about an axis and including a plurality of rotor poles, said rotor assembly being arranged and disposed for magnetic interaction with said at least one stator assembly.
4. A method for constructing an axial airgap, polyphase dynamoelectric machine, comprising:
(a) providing at least one stator assembly comprising a backiron section and a plurality of tooth sections, said stator assembly having a slot having a slot width between each adjacent pair of said tooth sections and a plurality of stacked stator phase windings, each winding encircling one or more of said tooth sections and occupying substantially the full available slot width, and said stator assembly comprising low core loss magnetic material characterized by a core loss less than “L” when operated at an excitation frequency “f” to a peak induction level “B max ” wherein L is given by the formula L=12·f·B 1.5 +30·f 2.3 ·B 2.3 , the core loss, excitation frequency and peak induction level being measured in watts per kilogram, kilohertz, and teslas, respectively; and
(b) providing at least one rotor assembly supported for rotation about an axis and including a plurality of rotor poles, said rotor assembly being arranged and disposed for magnetic interaction with said at least one stator assembly.