US5705902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Halbach array DC motor/generator
Assignee: University of California
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Filing: 1995-02-03
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Granted: 1998-01-06
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Expires: 2015-02-03
Abstract
Abstract A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.
Inventors
- 👤 Bernard T. Merritt
- 👤 Gary R. Dreifuerst
- 👤 Richard F. Post
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:14
CPC Classifications
H; H02; H02K; H02K21/00; H02K21/12; H02K21/22; B; B60; B60L; B60L15/00; B60L15/02; B60L15/025; B60L15/20; B60L50/00; B60L50/30; B60L50/50; B60L50/51; H02K1/00; H02K1/06; H02K1/22; H02K1/27; H02K1/2786; H02K1/2787; H02K1/2789; H02K1/2791; H02K1/2792; H02K7/00; H02K7/02; H02K7/025; H02M; H02M7/00; B60L2240/00; B60L2240/40; B60L2240/42; B60L2240/421; B60L2240/423; Y; Y02; Y02E; Y02E60/00; Y02E60/16; Y02T; Y02T10/00; Y02T10/60; Y02T10/64; Y02T10/70; Y02T10/72
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
121 words
An electric machine, comprising: a cylindrical rotor comprising an array of permanent magnets that provide a uniform dipole field with no necessity for the use of laminated iron, wherein said array of permanent magnets comprise bars of identical permanent magnets assembled in a circle, wherein said bars are dipole elements, each bar of said bars having a vector direction of magnetization that rotates at twice the rate as that of a vector rotating about said circle pointing from the center of said uniform dipole field to the center of said elements; a stator inserted down the axis of said dipole field, said stator comprising windings; and means for commutating said windings; wherein said rotor is on the outside of said stator.
Claim 2
Dependent Claim
121 words
An electric machine, comprising: a cylindrical rotor comprising an array of permanent magnets that provide a uniform dipole field with no necessity for the use of laminated iron, wherein said array of permanent magnets comprise bars of identical permanent magnets assembled in a circle, wherein said bars are dipole elements, each bar of said bars having a vector direction of magnetization that rotates at twice the rate as that of a vector rotating about said circle pointing from the center of said uniform dipole field to the center of said elements; a stator inserted down the axis of said dipole field, said stator comprising windings; and means for commutating said windings; wherein said rotor is on the outside of said stator.
Claim 3
Dependent Claim
40 words
The electric machine of claim 1, wherein said bars are selected from a group consisting of square bars, octagonal bars, 12 sided bars and circular cross-section bars, wherein said circular cross-section bars have fiducial marks to indicate their magnetization directions.
Claim 4
Dependent Claim
33 words
The electric machine of claim 2, wherein said octagonal bars have a direction of magnetization that rotates 90 degrees when the angular position of said bars in said array rotates through 45 degrees.
Claim 5
Dependent Claim
32 words
The electric machine of claim 2, wherein said 12 sided bars have a magnetization that rotates 60 degrees as the angular position of said bars in said array rotates through 30 degrees.
Claim 6
Dependent Claim
31 words
The electric machine of claim 2, wherein said square bars have a magnetization that rotates 90 degrees as the angular position of said bars in said array rotates through 45 degrees.
Claim 7
Dependent Claim
51 words
The electric machine of claim 1, further comprising a circuit for providing energy to said electric machine, comprising: a regulator; wherein said commutating means comprise an electronic commutator electrically connected in parallel to said regulator; and wherein said windings are electrically connected to receive a direct current from said electronic commutator.
Claim 8
Dependent Claim
47 words
The electric machine of claim 6, wherein said regulator is a Buck regulator comprising in parallel: a source of DC voltage in series with an IGBT; a diode; and a capacitor; wherein said Buck regulator further comprises an inductor electrically connected between said capacitor and said diode.
Claim 9
Dependent Claim
73 words
The electric machine of claim 6, wherein said electronic commutator comprises three parallel branches, each branch comprising two series electrically connected opening switches selected from a group consisting of IGBTs, BJTs, FETs, GTOs, and MCTs; wherein said three electrically parallel branches are electrically connected in parallel with said regulator; and wherein said windings comprise three phases, one phase each of said three phases electrically connected between said two series electrically connected opening switches.
Claim 10
Dependent Claim
30 words
The electric machine of claim 8, wherein one said opening switch of each branch of said three electrically parallel branches is pulse width modulated to control current in said windings.
Claim 11
Dependent Claim
116 words
An electric machine, comprising: a cylindrical rotor comprising an array of permanent magnets that provide a uniform dipole field with no necessity for the use of laminated iron, wherein said array of permanent magnets comprise bars of identical permanent magnets assembled in a circle, wherein said bars are dipole elements, each bar of said bars having a vector direction of magnetization that rotates at twice the rate as that of a vector rotating about said circle pointing from the center of said uniform dipole field to the center of said elements; a stator inserted down the axis of said dipole field, said stator comprising windings; and wherein said rotor is on the outside of said stator.
Claim 12
Dependent Claim
116 words
An electric machine, comprising: a cylindrical rotor comprising an array of permanent magnets that provide a uniform dipole field with no necessity for the use of laminated iron, wherein said array of permanent magnets comprise bars of identical permanent magnets assembled in a circle, wherein said bars are dipole elements, each bar of said bars having a vector direction of magnetization that rotates at twice the rate as that of a vector rotating about said circle pointing from the center of said uniform dipole field to the center of said elements; a stator inserted down the axis of said dipole field, said stator comprising windings; and wherein said rotor is on the outside of said stator.
Claim 13
Dependent Claim
44 words
The electric machine of claim 10, wherein said bars of identical permanent magnets are selected from a group consisting of square bars, octagonal bars, 12 sided bars and circular cross-section bars, wherein said circular cross-section bars have fiducial marks to indicate their magnetization directions.
Claim 14
Dependent Claim
33 words
The electric machine of claim 11, wherein said octagonal bars have a direction of magnetization that rotates 90 degrees when the angular position of said bar in said array rotates through 45 degrees.
Claim 15
Dependent Claim
34 words
The electric machine of claim 11, wherein said 12 sided bars have a direction of magnetization that rotates 60 degrees as the angular position of said bar in said array rotates through 30 degrees.
Claim 16
Dependent Claim
33 words
The electric machine of claim 11, wherein said square bars have a direction of magnetization that rotates 90 degrees as the angular position of said bar in said array rotates through 45 degrees.
Claim 17
Dependent Claim
44 words
The electric machine of claim 10, further comprising a circuit for extracting energy from said electric machine, comprising: a regulator; and a diode bridge electrically connected in parallel to said regulator; wherein said windings are electrically connected to provide current to said diode bridge.
Claim 18
Dependent Claim
46 words
The electric machine of claim 15, wherein said regulator comprises a boost regulator comprising in parallel: a DC voltage source in series with a diode; an IGBT; and a capacitor; wherein said boost regulator further comprises an inductor electrically connected between said IGBT and said capacitor.
Claim 19
Dependent Claim
60 words
The electric machine of claim 15, wherein said diode bridge comprises three branches electrically connected in parallel with said regulator; wherein each branch of said three branches comprises two diodes electrically connected in series; wherein said windings comprise three phases, one phase each of said three phases electrically connected between said two series electrically connected diodes of said diode bridge.
Claim 20
Dependent Claim
16 words
The electric machine of claim 10, wherein said array of permanent magnets comprise a Halbach array.
Claim 21
Dependent Claim
12 words
The electric machine of claim 1, wherein said permanent magnets comprise NdFeB.
Claim 22
Dependent Claim
12 words
The electric machine of claim 1, wherein said commutating means comprise brushes.
Claim 23
Dependent Claim
17 words
The electric machine of claim 1, wherein said rotor is constructed using an eight segment Halbach array.
Claim 24
Dependent Claim
12 words
The electric machine of claim 1, wherein said permanent magnets comprise ceramic.
Claim 25
Dependent Claim
11 words
The electric machine of claim 1, wherein said windings are multiphase.
Claim 26
Dependent Claim
12 words
The electric machine of claim 1, wherein said windings are three phase.
Claim 27
Dependent Claim
12 words
The electric machine of claim 1, wherein said windings comprise Litz wire.
Claim 28
Dependent Claim
11 words
The electric machine of claim 1, wherein said windings comprise copper.
Claim 29
Dependent Claim
85 words
The electric machine of claim 1, further comprising a circuit comprising: a Buck/Boost regulator; and wherein said commutating means comprise an electronic commutator electrically connected parallel to said Buck/Boost regulator, wherein said electronic commutator comprises three parallel branches, wherein each branch comprises two series connected opening switches with antiparallel diodes; wherein said windings are electrically connected to said electronic commutator, wherein each phase of said windings are electrically connected to a different branch of said electronic commutator between each said two series connected opening switches.
Claim 30
Dependent Claim
80 words
The electric machine of claim 10, further comprising a circuit comprising: a Buck/Boost regulator; and an electronic commutator electrically connected parallel to said Buck/Boost regulator, wherein said electronic commutator comprises three parallel branches, wherein each branch comprises two series connected opening switches with antiparallel diodes; wherein said windings are electrically connected to said electronic commutator, wherein each phase of said windings are electrically connected to a different branch of said electronic commutator between each said two series connected opening switches.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-05 | 2001-07-07 | 2002-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-05 | 2005-07-07 | 2006-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-05 | 2009-07-07 | 2010-01-06 | $7700.00 | Window Closed / Lapsed |