Patent US4520116A successfully refreshed from Google Patents.
Patent EP0251785A2 successfully refreshed from Google Patents.
EP0251785A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electric motor control method and apparatus
Assignee: Seagate Technology LLC
•
Filing: 1987-07-01
•
Granted: —
•
Expires: 2007-07-01
Abstract
Abstract Control and synchronization of a polyphase, brushless DC motor (M) (used for a hard-disk system) during initial start-up of the motor, is effected by monitoring rotor position using a high-frequency commutation: A short current pulse is applied to each power phase (A,B,C) of the motor, and motor current conducted in response thereto is measured to determine therefrom positional information of the rotor. From such positional information the identity of the appropriate motor phase to which is applied a torque-producing current is determined. Cycles of high-frequency commutation and application of torque-producing current are performed, until the rotational speed of the rotor has attained a predetermined RPM. Motor speed is controlled in synchronized, increasing fashion by continued monitoring of the motor current and back-EMF, until a desired rotational RPM is attained, whereupon torque-producing current is sequentially applied to each motor phase in synchronization with the rotor position by deriving positional information from the disk (34).
Inventors
- 👤 John P. Squires
- 👤 Louis J. Shrinkle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 08:44
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/20; H02P6/22; H02P6/06; H02P6/14; H02P6/16; H02P6/18; H02P6/185
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
63 words
A commutatorless direct current motor comprising: a) means for establishing a plurality of first magnetic fields; b) means for inducing a second magnetic field; c) control means, coupled to said inducing means, for directing a short-period inducement of said second magnetic field, said control means including means for monitoring the interaction of said short-period induced second magnetic field with said first magnetic fields.
Claim 2
Dependent Claim
63 words
A commutatorless direct current motor comprising: a) means for establishing a plurality of first magnetic fields; b) means for inducing a second magnetic field; c) control means, coupled to said inducing means, for directing a short-period inducement of said second magnetic field, said control means including means for monitoring the interaction of said short-period induced second magnetic field with said first magnetic fields.
Claim 3
Dependent Claim
44 words
The motor of Claim 1 wherein said establishing means is rotatable with respect to said inducing means and wherein said control means identifies the rotational orientation of said short-period induced second magnetic field with respect to a specific one of said first magnetic fields.
Claim 4
Dependent Claim
74 words
The motor of Claim 2 wherein said control means, in response to said monitoring means, identifies a subset of the possible rotational positions of said establishing means with respect to said inducing means and wherein said control means further includes logic means for identifying the one rotational position of said inducing means from said subset of possible rotational positions that corresponds to the rotational position of said specific one of said first magnetic fields.
Claim 5
Dependent Claim
62 words
The motor of Claim 3 wherein said inducing means includes a plurality of windings, wherein each short-period inducement of said second magnetic field is obtained by the application of a current pulse through a respective phase pair of said windings as selected by said control means, wherein said monitoring means monitors the current pulse response of each said phase pair of windings.
Claim 6
Dependent Claim
30 words
The motor of Claim 4 wherein said monitoring means detects the peak voltage obtained in response to the application of each current pulse to each said phase pair of windings.
Claim 7
Dependent Claim
172 words
In a brushless DC motor having multiple windings and a rotor, apparatus for controlling ordered application of electrical current to the windings, comprising: circuit means coupled to the windings for selectively creating current paths therethrough in response to control signals; means coupled to the DC motor for producing a sense signal indicative of current conducted by the DC motor; and control means coupled to the circuit means and to the sensing means for providing the control signals in a manner to cause current to flow through current paths selectively formed by the circuit means in response to the control signals, effecting rotation of the rotor ; the control means including means for producing control signals to cause selective application of high-frequency current pulses to the windings and for monitoring the sense signal to determine which of the current pulses produces a highest amplitude sense signal relative to those of the other current pulses, the control means being operable in response to said determination to provide predetermined control signals to the circuit means.
Claim 8
Dependent Claim
172 words
In a brushless DC motor having multiple windings and a rotor, apparatus for controlling ordered application of electrical current to the windings, comprising: circuit means coupled to the windings for selectively creating current paths therethrough in response to control signals; means coupled to the DC motor for producing a sense signal indicative of current conducted by the DC motor; and control means coupled to the circuit means and to the sensing means for providing the control signals in a manner to cause current to flow through current paths selectively formed by the circuit means in response to the control signals, effecting rotation of the rotor ; the control means including means for producing control signals to cause selective application of high-frequency current pulses to the windings and for monitoring the sense signal to determine which of the current pulses produces a highest amplitude sense signal relative to those of the other current pulses, the control means being operable in response to said determination to provide predetermined control signals to the circuit means.
Claim 9
Independent Claim
108 words
A method for initiating and controlling the rotation of a rotor of a brushless DC motor of the type having multiple windings, related as phases for conducting torque-producing current therethrough, comprising the steps of: sequentially powering each phase of the DC motor for a short predetermined time period; obtaining a peak amplitude value of the current conducted by the motor when a phase is powered during each corresponding short predetermined time period; determining a one peak amplitude value having a magnitude greater than the other peak amplitude values; and applying a torque-producing current to the DC motor in a phase determined by the determined one peak amplitude value.
Claim 10
Independent Claim
108 words
A method for initiating and controlling the rotation of a rotor of a brushless DC motor of the type having multiple windings, related as phases for conducting torque-producing current therethrough, comprising the steps of: sequentially powering each phase of the DC motor for a short predetermined time period; obtaining a peak amplitude value of the current conducted by the motor when a phase is powered during each corresponding short predetermined time period; determining a one peak amplitude value having a magnitude greater than the other peak amplitude values; and applying a torque-producing current to the DC motor in a phase determined by the determined one peak amplitude value.
Claim 11
Dependent Claim
25 words
The method of Claim 7 including the steps of: deriving the rotational speed of the rotor from successive determined ones of the peak amplitude values.
Claim 12
Dependent Claim
75 words
The method of Claim 8 including the steps of: at a predetermined rotational speed of the rotor, terminating the powering, obtaining, determining, applying, and deriving steps; obtaining a static motor current value; applying a motor current to the determined power phase of the motor; measuring the motor current; and switching application of the motor current to the next sequential power phase of the motor when the measured motor current exceeds the static motor current value.
Claim 13
Dependent Claim
97 words
A commutatorless direct current motor comprising: a) armature means for inducing relative rotational movement, said armature means including a plurality of windings having first and second ends, said first ends of said windings being connected together; b) means for supporting a plurality of magnets rotatable with respect to said armature means; and c) control means, coupled to said respective second ends of said windings, for providing commutated power to said windings, said control means including means for applying a high-frequency signal to said windings to determine the rotational orientation of said magnets with respect to said windings.
Claim 14
Dependent Claim
97 words
A commutatorless direct current motor comprising: a) armature means for inducing relative rotational movement, said armature means including a plurality of windings having first and second ends, said first ends of said windings being connected together; b) means for supporting a plurality of magnets rotatable with respect to said armature means; and c) control means, coupled to said respective second ends of said windings, for providing commutated power to said windings, said control means including means for applying a high-frequency signal to said windings to determine the rotational orientation of said magnets with respect to said windings.
Claim 15
Dependent Claim
35 words
The motor of Claim 10 wherein said high-frequency signal application means is coupled to each of said second ends of said windings to enable the application of said high-frequency signal to each of said windings.
Claim 16
Dependent Claim
36 words
The motor of Claim 11 wherein said control means further includes means, coupled to each of said second ends of said windings, for measuring the response of said windings to the application of said high-frequency signal.
Claim 17
Dependent Claim
35 words
The motor of Claim 12 wherein said measuring means measures the peak value of the return high-frequency signal, obtained in response to the application of said high-frequency signal, with respect to each of said windings.
Claim 18
Dependent Claim
43 words
The motor of Claim 13 wherein said high-frequency signal application means selectively applies said high-frequency signal to pairs of said second ends of said windings such that said high-frequency signal is serially conducted through two of said windings via their respective first ends.
Claim 19
Dependent Claim
35 words
The motor of Claim 14 wherein said control means, responsive to said measuring means, selectively determines the commutation order of applying power to said windings to rotate said magnet support means in a predetermined direction.
Claim 20
Dependent Claim
34 words
The motor of Claim 15 wherein said control means is capable of relying exclusively on said measuring means for determining the rotational orientation of said magnet support means with respect to said armature means.
Claim 21
Dependent Claim
101 words
In a commutatorless direct current motor having an armature and a multiple-magnet rotor, wherein said armature includes a plurality of windings for generating torque- inducing magnetic fields and said multiple-magnet rotor is caused to rotate in response to said magnetic fields relative to said armature, an improvement permitting the unique armature relative rotational position of said multiple-magnet rotor to be electively identified exclusively through the use of said windings as positional sensors, said improvement comprising: a) control means for applying a high-frequency signal to said windings; and b) means for detecting the respective response of said windings to said high-frequency signal.
Claim 22
Dependent Claim
101 words
In a commutatorless direct current motor having an armature and a multiple-magnet rotor, wherein said armature includes a plurality of windings for generating torque- inducing magnetic fields and said multiple-magnet rotor is caused to rotate in response to said magnetic fields relative to said armature, an improvement permitting the unique armature relative rotational position of said multiple-magnet rotor to be electively identified exclusively through the use of said windings as positional sensors, said improvement comprising: a) control means for applying a high-frequency signal to said windings; and b) means for detecting the respective response of said windings to said high-frequency signal.
Claim 23
Dependent Claim
49 words
The motor of Claim 17 wherein said control means selectively applies said high-frequency signal to said windings, wherein said detecting means detects a distinguishing response from said windings and wherein said control means, responsive to said detecting means, determines the unique armature relative rotational position of said multiple-magnet rotor.
Claim 24
Dependent Claim
61 words
The motor of Claim 18 wherein said control means provides said high-frequency signal as a short-duration current pulse and wherein said control means monitors the peak voltage developed across said windings in response to the application of said short-duration current pulse, the winding for which the highest peak voltage is detected being associated with a specific location on said multiple-magnet rotor.
Claim 25
Dependent Claim
46 words
The motor of Claim 19 wherein said control means applies said short-duration current pulse to each phase winding of said motor and wherein said short-duration current pulse has a predetermined duration insufficient to alter the rotational position of said multiple-magnet rotor with respect to said armature.
Claim 26
Dependent Claim
161 words
A commutatorless direct current motor comprising: a) an armature including a plurality of windings having first and second ends, said first ends of said windings being connected together, whereby sets of two said second ends define phase pairs of said windings; b) a permanent magnet rotor assembly including a plurality of magnets and rotatable with respect to said armature; and c) control means, coupled to said respective second ends of said windings, for selectively providing commutation power to phase pairs of said windings, for successively applying a short-duration current pulse to each phase pair of said windings, for detecting the peak voltage developed across said second ends of each phase pair of said windings and for comparing the detected peak voltages of each phase pair of said windings, said control means identifying a specific one of said magnets as being positional related to the one of the phase pairs of said windings corresponding to the largest phase pair peak voltage detected.
Claim 27
Dependent Claim
161 words
A commutatorless direct current motor comprising: a) an armature including a plurality of windings having first and second ends, said first ends of said windings being connected together, whereby sets of two said second ends define phase pairs of said windings; b) a permanent magnet rotor assembly including a plurality of magnets and rotatable with respect to said armature; and c) control means, coupled to said respective second ends of said windings, for selectively providing commutation power to phase pairs of said windings, for successively applying a short-duration current pulse to each phase pair of said windings, for detecting the peak voltage developed across said second ends of each phase pair of said windings and for comparing the detected peak voltages of each phase pair of said windings, said control means identifying a specific one of said magnets as being positional related to the one of the phase pairs of said windings corresponding to the largest phase pair peak voltage detected.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.