Permanent magnet electric motor
First Claim
Patent Images
1. An electric motor for reducing torque ripple comprising:
- a rotor,a plurality of magnets positioned about the rotor, anda stator including a plurality of stator teeth configured to form at least two slot openings each having a slot opening width wo and a slot opening height ho,wherein one or more of the stator teeth include a dummy channel having a channel height wn and a channel width wb, andwherein at least one of the slot opening width wo, the slot opening height ho, the channel height wn, and the channel width wb, are selected so as to minimize or reduce cogging torque.
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Abstract
An electric motor for reducing torque ripple includes a rotor, a plurality of magnets positioned about the rotor, and a stator including a plurality of stator teeth configured to form at least two slot openings each having a slot opening width wo and a slot opening height ho. One or more of the stator teeth include a dummy channel having a channel height wn and a channel width wb. At least one of the slot opening width wo, the slot opening height ho, the channel height wn, and the channel width wb, are selected so as to minimize or reduce cogging torque.
129 Citations
21 Claims
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1. An electric motor for reducing torque ripple comprising:
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a rotor, a plurality of magnets positioned about the rotor, and a stator including a plurality of stator teeth configured to form at least two slot openings each having a slot opening width wo and a slot opening height ho, wherein one or more of the stator teeth include a dummy channel having a channel height wn and a channel width wb, and wherein at least one of the slot opening width wo, the slot opening height ho, the channel height wn, and the channel width wb, are selected so as to minimize or reduce cogging torque. - View Dependent Claims (2)
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3. An electric motor for reducing torque ripple comprising:
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a rotor, a plurality of magnets positioned about the rotor so as to provide at least ten magnetic poles, and a stator configured to form at least twelve slots; wherein the magnets are skewed with respect to the rotational axis of the motor. - View Dependent Claims (4, 5, 6, 7, 8)
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9. An electric motor for reducing torque ripple including a stator having t slots, a shaft having a shaft axis, a rotor positioned about the shaft and having p poles, t and p having a least common multiple M, a first magnet ring positioned on the rotor, the first magnet ring comprising magnets each occupying a magnet angle δ
- on the rotor, and a second magnet ring positioned on the rotor, the second magnet ring comprising magnets each occupying a magnet angle δ
on the rotor, wherein the second magnet ring is shifted a non-zero number of degrees relative to the first magnet ring such that an end of each magnet within the second magnet ring is located at a different angular position than an end of each magnet within the first magnet ring relative to the shaft axis. - View Dependent Claims (10, 11, 12, 13)
- on the rotor, and a second magnet ring positioned on the rotor, the second magnet ring comprising magnets each occupying a magnet angle δ
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14. An electric motor for reducing torque ripple including a stator having t slots, a shaft having a shaft axis, a rotor positioned about the shaft and having p poles, t and p having a least common multiple M, a magnet ring positioned on the rotor, the magnet ring comprising magnets each occupying a magnet angle δ
- on the rotor, wherein the magnet angle δ
is selected to minimize one or more harmonic components in line to line back emf. - View Dependent Claims (15, 16)
- on the rotor, wherein the magnet angle δ
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17. An electric motor for reducing torque ripple including:
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a rotor having a plurality of magnets positioned thereon, and a stator including a plurality of stator teeth configured to form at least a first set of slot openings and a second set of slot openings, wherein a conductor is wound around the plurality of stator teeth so as to form a winding which spans at least 30 mechanical degrees or 150 electrical degrees. - View Dependent Claims (18, 19)
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20. An electric motor for reducing torque ripple including:
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a rotor having a rotor diameter D, a plurality of magnets positioned on the rotor, a puck magnet having a diameter d and positioned on the rotor, and a stator including a plurality of stator teeth configured to form at least a first set of slot openings and a second set of slot openings; wherein diameter d is less than rotor diameter D.
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21. An electric motor for reducing torque ripple including:
- a rotor having a plurality of magnets positioned thereon, and a stator including a plurality of stator teeth configured to form at least a first set of slot openings and a second set of slot openings, wherein a conductor is wound around the plurality of stator teeth so as to provide a symmetrical distribution of windings with reference to the rotor, thereby reducing or minimizing an unbalanced radial pull of the electric motor.
Specification