Patent US4174244A successfully refreshed from Google Patents.
EP0210047A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Motor control and operation
Assignee: Maghemite Inc
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Filing: 1986-07-16
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Granted: —
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Expires: 2006-07-16
Abstract
Abstract Novel winding arrangements and control circuits for brush less direct-current motors are described. Stator windings are arranged to produce an essentially continuous torque in each winding phase from D.C. current pulses each of about one-half the duration of a two-pole cycle of rotor movement. An electronic control circuit comprises one electronic power switch for each winding group or winding phase in the stator windings. One or two D.C. current pulses are applied to the windings for each two-pole cycle of rotor movement, depending on the arrangement of the coils. CEMF voltage generated in the coils is sensed and a change in the polarity thereof is used to control switching of the D.C. current between coils.
Inventors
- 👤 John S. Mackelvie
- 👤 Eric Whitely
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 20:15
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/12; H02P; H02P6/00; H02P6/08
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
103 words
A brushless direct-current motor comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles so as to produce torque from D.C. current applied to said windings, the improvement wherein said stator windings are arranged to produce an essentially continuous torque in each winding phase from D.C. current pulses each of about one-half the duration of a two-pole cycle of rotor movement, and an electronic control circuit for said motor comprising one electronic power switch for each winding group or winding phase in said stator windings.
Claim 2
Dependent Claim
103 words
A brushless direct-current motor comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles so as to produce torque from D.C. current applied to said windings, the improvement wherein said stator windings are arranged to produce an essentially continuous torque in each winding phase from D.C. current pulses each of about one-half the duration of a two-pole cycle of rotor movement, and an electronic control circuit for said motor comprising one electronic power switch for each winding group or winding phase in said stator windings.
Claim 3
Dependent Claim
57 words
The brushless D.C. motor of claim 1, wherein the windings included in each winding phase are sub-divided into a plurality of coil-groups with each coil group being one winding circuit in a winding phase and each said coil group is operated by its own electronic switch in parallel with the other coil groups in the winding phase.
Claim 4
Dependent Claim
45 words
The brushless D.C. motor of claim 2, wherein the windings included in each winding phase are sub-divided into two individual coil groups, and the individual coil groups are mounted to the stator phase-displaced from each other in stator mounting slots by one rotor pole pitch.
Claim 5
Dependent Claim
33 words
The brushless D.C. motor of claim 3, wherein each of the individual phase-displaced coil groups is further subdivided into at least two parallel winding circuits which are wound into the same stator slots.
Claim 6
Dependent Claim
49 words
The brushless D.C. motor of claim 4, wherein one electronic power switch is employed for each said winding circuit into which the coil group is sub-divided and such power switches are arranged to be turned on and off in parallel for those winding circuits intended to operate in parallel.
Claim 7
Dependent Claim
26 words
The brushless D.C. motor of claim 5, wherein all power switches intended to operate winding circuits in parallel are controlled from a single pulse-timing logic circuit.
Claim 8
Dependent Claim
49 words
The brushless D.C. motor of claim 6, wherein split-phase motor winding sub-division are operated by a single logic system which controls the two phase-division so as to turn the D.C. pulse on for one of said individual coil-groups as the D.C. pulse for the other individual-coil is turned off.
Claim 9
Dependent Claim
58 words
The brushless D.C. motor of claim 7, wherein logic circuits are located at the terminals of rotor windings to sense CEMF voltages of windings not carrying torque-producing electric current at the time of sensing and are arranged to employ such sensed CEMF voltages as control signals to turn on or off D.C. power pulses to the motor windings.
Claim 10
Dependent Claim
34 words
The brushless D.C. motor of claim 8, wherein an over-current protection circuit is provided in association with the power switches to limit power switch on-time under conditions likely to produce overheating in the switch.
Claim 11
Dependent Claim
44 words
The brushless D.C. motor of claim 9, wherein a starter circuit is provided which provides timed and phase-sequenced D.C. pulses to the motor windings until the motor is able to reach a speed at which the CEMF becomes sufficient to effect the pulse-timing function.
Claim 12
Dependent Claim
115 words
In a brushless D.C. dynamoelectric machine, which comprises: a disk-like rotor element comprising hard ferrite toroid means providing a plurality of magnetic poles of alternating polarity and mounted for rotation about its axis, a disk-like stator element comprising soft ferrite toroid means and mounted coaxially with and spaced apart from the rotor element, said soft ferrite toroid means being formed with radially-directed coil winding receiving slots, and electrical coil windings mounted to said stator in said slots and each spanning one rotor pole pitch; the improvement wherein: said electrical coil windings with respect to each spanned one rotor pole pitch are electrically connected in series and are wound in said slots alternately clockwise and anticlockwise.
Claim 13
Dependent Claim
115 words
In a brushless D.C. dynamoelectric machine, which comprises: a disk-like rotor element comprising hard ferrite toroid means providing a plurality of magnetic poles of alternating polarity and mounted for rotation about its axis, a disk-like stator element comprising soft ferrite toroid means and mounted coaxially with and spaced apart from the rotor element, said soft ferrite toroid means being formed with radially-directed coil winding receiving slots, and electrical coil windings mounted to said stator in said slots and each spanning one rotor pole pitch; the improvement wherein: said electrical coil windings with respect to each spanned one rotor pole pitch are electrically connected in series and are wound in said slots alternately clockwise and anticlockwise.
Claim 14
Dependent Claim
66 words
The machine of claim 11 wherein the number of said radially-directed slots is twice the number of the magnetic poles of said rotor element, said electrical coil windings comprise two sets of said series-connected windings, the windings of each set are located in rotor pole pitch-spaced pairs of said slots so that the windings of each set overlap each other for half a rotor pole pitch.
Claim 15
Dependent Claim
79 words
The machine of claim 12 wherein each said set of windings is comprised of a plurality of parallel coil groups which are sub-divided into two individual coil groups which are mounted in said slots phase-displaced from each other by one rotor pole pitch, whereby with respect to each spanned pole pitch there is provided one individual coil group wound in the slots in a clockwise direction and another individual coil group wound in the slots in an anticlockwise direction.
Claim 16
Dependent Claim
36 words
The machine of claim 13 wherein an electronic power switch is provided for each individual winding group and the electronic power switches for each set of windings are connected in parallel for simultaneous activation and deactivation.
Claim 17
Independent Claim
96 words
A method of operating a brushless D.C. motor, comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles, which comprises: applying either one or two D.C. current pulses to said windings for each two-pole cycle of rotor movement, each said D.C. current pulses being of one-half cycle duration to generate torque, and effecting said D.C. current pulse application through the alternate activation and deactivation of one only electronic switch per winding group or phase group in said windings.
Claim 18
Independent Claim
96 words
A method of operating a brushless D.C. motor, comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles, which comprises: applying either one or two D.C. current pulses to said windings for each two-pole cycle of rotor movement, each said D.C. current pulses being of one-half cycle duration to generate torque, and effecting said D.C. current pulse application through the alternate activation and deactivation of one only electronic switch per winding group or phase group in said windings.
Claim 19
Dependent Claim
39 words
The method of claim 15 including sensing CEMF voltages in windings not carrying torque-producing electric current and employing the change in polarity of said sensed CEMF voltages as control signals to effect activation and deactivation of said electronic switches.
Claim 20
Independent Claim
129 words
A method of controlling the alternate application of D.C. pulses to a brushless D.C. motor comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles and including two sets of individual electrical coils connected in series within each set and each spanning one rotor pole pitch, the individual coils in each set being offset from each other by one-half rotor pole pitch, which comprises sensing CEMF voltage generated by the one of said sets of individual electrical coils to which a D.C. current pulse is not being applied, and controlling switching of the D.C.current to said one set of coils in response to a change in polarity of said sensed CEMF.
Claim 21
Independent Claim
129 words
A method of controlling the alternate application of D.C. pulses to a brushless D.C. motor comprising a permanent magnet rotor having a plurality of magnetic poles and a stator bearing windings arranged to interact with the magnetic field produced by the magnetic poles and including two sets of individual electrical coils connected in series within each set and each spanning one rotor pole pitch, the individual coils in each set being offset from each other by one-half rotor pole pitch, which comprises sensing CEMF voltage generated by the one of said sets of individual electrical coils to which a D.C. current pulse is not being applied, and controlling switching of the D.C.current to said one set of coils in response to a change in polarity of said sensed CEMF.
References Cited (Backward Citations)
No citation records indexed.
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