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WO1998042063A1 - Moteur a courant continu produisant une force radiale - Google Patents

Moteur a courant continu produisant une force radiale Download PDF

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Publication number
WO1998042063A1
WO1998042063A1 PCT/US1997/004197 US9704197W WO9842063A1 WO 1998042063 A1 WO1998042063 A1 WO 1998042063A1 US 9704197 W US9704197 W US 9704197W WO 9842063 A1 WO9842063 A1 WO 9842063A1
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WO
WIPO (PCT)
Prior art keywords
motor
phase
actuator
rotor
windings
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1997/004197
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English (en)
Inventor
Gunter K. Heine
Hans Leuthold
Christian Fleury
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seagate Technology LLC
Original Assignee
Seagate Technology LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seagate Technology LLC filed Critical Seagate Technology LLC
Priority to GB9921852A priority Critical patent/GB2337647B/en
Priority to HK00102978.2A priority patent/HK1023858B/xx
Priority to JP54045998A priority patent/JP4034358B2/ja
Priority to PCT/US1997/004197 priority patent/WO1998042063A1/fr
Priority to DE19782264T priority patent/DE19782264T1/de
Priority to US09/029,043 priority patent/US6201322B1/en
Priority to KR10-1999-7008496A priority patent/KR100393858B1/ko
Publication of WO1998042063A1 publication Critical patent/WO1998042063A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings
    • H02K7/09—Structural association with bearings with magnetic bearings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/044—Active magnetic bearings
    • F16C32/0444—Details of devices to control the actuation of the electromagnets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/044—Active magnetic bearings
    • F16C32/0474—Active magnetic bearings for rotary movement
    • F16C32/0493—Active magnetic bearings for rotary movement integrated in an electrodynamic machine, e.g. self-bearing motor
    • F16C32/0497—Active magnetic bearings for rotary movement integrated in an electrodynamic machine, e.g. self-bearing motor generating torque and radial force
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
    • G11B19/20—Driving; Starting; Stopping; Control thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2370/00—Apparatus relating to physics, e.g. instruments
    • F16C2370/12—Hard disk drives or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2380/00—Electrical apparatus
    • F16C2380/26—Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K16/00—Machines with more than one rotor or stator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/03—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems

Definitions

  • the system is useful with all known brushless D.C. motors; it is also useful with motor designs such as shown in U. S. Patent No. 5,590,003 issued December 31, 1996, entitled “IRONLESS SPINDLE MOTOR FOR A DISC DRIVE", as well as U. S. Patent No. 5,598,071 issued January 28, 1997, entitled “SINGLE- PHASE SPINDLE MOTOR”, both assigned to the assignee of this invention and incorporated herein by reference.
  • the present invention relates generally to motors and the vibrations or resonances which are set up within such motors; particular applications or examples will be given with respect to spindle motors used in disc drive assemblies, but the application of this invention is not limited to these specific examples.
  • the invention discloses actuators for eliminating such resonances. BACKGROUND OF THE INVENTION
  • NRR non-repetitive run-out
  • mechanical modes of the motor and the disc pack correspond to predicted mechanical resonance, which are in turn exited by ball bearing vibration.
  • NRR magnitude the vibrational characteristics of the drive have to be modified.
  • an object of the present invention is to damp out the resonances which occur in a rotating system such as a disc drive spindle motor.
  • a related objective is to stabilize the spin axis of a rotating system in a given position.
  • the term "attenuation" is directly related to the fact that the force applied is out of phase with the resonant movements within the system. This is as opposed to the idea of adding a force which directly opposes the resonances which are occurring within the system, which would thereby add stiffness to the system, and constitutes the approach taken by the prior art. This would be the approach taken by an electromagnetic bearing, or the like, being added to the system.
  • damping actuator may comprise windings of a motor supporting the rotating system.
  • Another objective of the invention is to establish that the actuator for damping out movements may comprise specific windings of the motor supporting the rotating system having currents of selected magnitude and phase applied thereto.
  • Yet another objective of the invention is to demonstrate an approach for selecting such windings in a motor, and the direction and magnitude of current flow in the winding to provide an effective damping actuator.
  • resonant movements are first simulated, and then a derivative of that representation is utilized to define a damping signal, lagging in phase, which controls the application of force to the system to damp out the resonance within the system.
  • the damping method taught by this invention comprises measuring the movements of the system in time, and then lagging that very same force by ninety degrees and applying that damping force to correct the tendency for that movement to occur.
  • a movement at a given velocity is countered by a counter movement at a given velocity, so that movements at high frequency are successfully damped out.
  • equations will be generated to demonstrate that a radial force to dampen resonant movements in a highly responsive manner can be generated using additional windings within a spindle motor which is used herein as an exemplary rotating system.
  • the coils are grouped in phases and energized to produce a radial force as required.
  • An appropriate exemplary circuit for taking the representation of the undesired movement and creating and damping force through the application of current to the additional windings is also disclosed.
  • the principles of the analysis and invention could be applied utilizing the windings already present in the motor.
  • the windings could be tapped, and currents necessary to generate the stabilizing radial force be added to the normal motor driving currents.
  • the regular driving currents could be turned off for a very brief period, and the calculated currents to create a radial force imposed on the same windings; the two currents could be alternated rapidly so that the momentum of the motor is maintained by these driving currents while the radial force is created by the calculated currents.
  • Figure IA shows that in supplying currents to a different combination of coils, it is possible to apply a torque on the rotor magnet.
  • Figure IB shows that in supplying currents to a different combination of coil, it is possible to apply a radial force on the rotor magnet.
  • Figure 2A shows a conductor placed in one slot of a Permanent Magnet Brushless DC Motor.
  • Figure 2B illustrates the assumption that the conductor is directly placed in the air gap between the core and the magnet.
  • Figure 3 A shows the force acting on one conductor placed in the airgap.
  • Figure 3B shows the action and reaction rule, and the forces acting on the magnet due to current flowing through a conductor placed in the airgap.
  • Figure 4 shows the projection of the force analyzed in Figure 3B on the x and y axis.
  • Figure 5 shows two forces acting on a magnet when a coil composed of two conductors is placed in the airgap.
  • Figure 6A shows a coil opening of one slot in a motor winding.
  • Figure 6B shows a coil opening of two slots in a motor winding.
  • Figure 7 shows 12 concentric coils placed in the 12 slots of the motor.
  • Figure 8 shows a three phase winding generating torque for an eight pole, twelve slot motor.
  • Figure 9 shows a single phase of six coils generating a radial force.
  • Figure 10 shows one rotating radial force.
  • Figure 1 1 shows two rotating radial forces in quadrature.
  • Figure 12 shows a two phase winding generating two radial forces in quadrature, and a coil opening of one slot.
  • Figure 13 shows a two phase winding generating two radial forces in quadrature, and a coil opening of two slots.
  • Figure 14A shows two rotating forces in quadrature.
  • Figure 14B shows three rotating forces separated by 120°.
  • Figure 15 shows a motor structure with two magnetic circuits.
  • Figures 16A and 16B are a perspective and sectional view of a slotless motor winding (cylinder placed in the airgap).
  • Figure 17 shows two rotating radial forces in quadrature.
  • Figure 18 shows a projection of the radial force vector onto the vectors of the forces generated by phases 1 and 2.
  • Figure 19 shows projections of the x and y radial force component vectors on the vector of the force generated by phase 1.
  • Figure 20 shows the relationship between a sum of two forces in quadrature and a sum of three forces having directions are separated by 120°.
  • Figure 21 is a block diagram of the phase one current calculation (expression a.59).
  • Figure 22 is a block diagram of means for processing one trigonometric function and one multiplication.
  • Figure 23 is a block diagram of means for generating the EPROM addresses as a function of the rotor position.
  • Figure 24 is a block diagram of means for generating the EPROM addresses as a function of the rotor position, with phase delay adjustment.
  • Figure 25 is a timing diagram corresponding to the block diagram of Figure 24.
  • Figure 26 is a circuit diagram using a transistor command signal of the motor driver to generate one pulse per electrical period.
  • Figure 27 illustrates using a transistor command signal of the motor drive to generate one pulse per electrical period; the timing diagram is related to the circuit of Figure 26.
  • Figure 28 is a block diagram for generating radial force utilizing a two- phase winding.
  • Figure 29 shows the phase delay effect on the radial force direction.
  • Figure 30 is a vertical section of a hard drive spindle motor.
  • Figure 31 is a block diagram of a circuit for measuring the response to a rotating radial force exitation.
  • Figure 32 illustrates the definition of the rotational axis angular position.
  • Figure 33 illustrates the exitation of the forward gyroscopic mode, measurement of the NOR components of a and ⁇ , applied against a signal providing one pulse per revolution.
  • Figure 34 illustrates the exitation of the forward gyroscopic mode; also shown is a Lissajou figure of the NRR components of and ⁇ .
  • Figure 35 illustrates the exitation of the backward gyroscopic mode, and measurement of the NRR components of and ⁇ ; a signal providing one pulse per revolution is also shown.
  • Figure 36 illustrates the exitation of the backward gyroscopic mode; also shown is a Lissajou figure of the NRR components of ⁇ and ⁇ .
  • Figure 37 shows rotor motion in plane xz.
  • Figure 38 is a bode plot of ⁇ wave magnitude.
  • Figure 39 is a bode plot of a wave phase delay.
  • Figure 40 is a bode plot of the ⁇ wave phase delay including the effect of synchronous multiplier phase delay.
  • Figure 41 is a bode plot of the wave phase delay, including the temporal delay introduced by the current amplifiers and by the measurement system.
  • Figure 42 illustrates correction of the temporal delay of the backward gyroscopic mode with a synchronous multiplier phase delay.
  • Standard design of spindle motor is intended to create a torque that spins the rotor.
  • the objective of the present work is to create an additional radial force within the spindle motor using the spindle components (like the magnet and the stack) and specially calculated currents supplied to the coils or windings.
  • Figures IA and IB show that by supplying a different combination of coils, it is possible to apply on the rotor magnet either a torque (Fig. 1 A) or a radial force (Fig. IB), depending on how the coil is wound, and the direction of current flow in the coil.
  • a separate set of coils is added to the motor.
  • the principles of the analysis and invention could be applied utilizing the windings already present in the motor.
  • the windings could be tapped, and currents necessary to generate the stabilizing radial force be added to the normal motor driving currents.
  • the regular driving currents could be turned off for a very brief period, and the calculated currents to create a radial force imposed on the same windings; the two currents could be alternated rapidly so that the momentum of the motor is maintained by these driving currents while the radial force is created by the calculated currents.
  • slotless motor is then presented, as well as the corresponding tables describing the motor configurations compatible with winding torque and/or radial force.
  • the force generation of one conductor placed in a magnetic field is based on the Fleming's left hand rule.
  • a conductor is placed in a magnetic field: if a current flows through the conductor, a force will act on it.
  • the direction of the force is given by left hand rule illustrated in the same figure and the magnitude of the force is given is given by the following equation:
  • B ⁇ peak value of the magnetic flux density. This value takes into account the airgap length, the type of magnet, the type of stack steel, the geometry of the teeth, the magnet magnetization, ...From this value, calculated as the first harmonic of the flux density distribution in the airgap of the real slotted motor, depends the determination of the exact torque value, but it does not affect the winding design in term of coil combinations. Based on the preceding assumptions, it is possible to determine the force acting on one conductor placed in the airgap as described in Fig. 3 A. As the magnetic flux density is given by equation (a2), the magnitude of this force is:
  • Figure 5 shows two forces acting on the magnet 50 when a coil 52 composed of two conductors is placed in the airgap. As the currents flowing through these conductors are flowing through the same coil, their magnitude is identical but their sign is opposite.
  • the torque expression can be written in a way to separate the influence of the coil openings from the coil and rotor positions a and ⁇ :
  • Expression (a. 12) shows that the coil openings can be chosen in order to maximize the torque.
  • the Cartesian components Fx and Fy of the resulting force acting on the magnet 50 can also be determined:
  • Cartesian components F x and F y (a.14) and (a.16) can transformed in the same way the torque expression (a.10) has been transformed in (a.12): to separate the influence of the coil openings from the coil and rotor positions ⁇ and
  • the FX component expression (a. 14) can be written in a way to separate the influence of the coil openings from the coil and rotor positions and ⁇ :
  • the Fy component expression (a.16) can be written in a way to separate the influence of the coil opening s from the coil and rotor positions ⁇ and ⁇ :
  • the method for designing a winding generating torque is a source of inspiration for finding a way to design a winding generating a radial force.
  • This section presents an example using an 8 pole, 12 slot configuration (Fig. 5).
  • Figure 6 A and 6B shows how conductors 60 can be placed in the slots 62 of a motor 64 also including magnet 66 to form a coil.
  • Figure 6A shows a coil 68 concentric about a tooth 69.
  • the exact conductor position in the slot is not really important to calculate the corresponding coil openings, 61.
  • the coil opening 61 is rather defined as the angle between the middle points of the two slots containing the coil conductors.
  • Figure 6B shows a coil with a two slot coil opening 63.
  • the coil opening s, 61 or 63 is chosen in order to maximize the torque magnitude and also to provide a winding easy to build.
  • the following table I shows that with a one slot coil opening, the winding will be concentric, and thus to build, without losing torque.
  • Tab. A.9 Value of coefficient k. in function of the coil opening s.
  • Figure 7 shows that 12 concentric coils 70 can be placed in the 12 slots 72 of the motor 73.
  • Tab. A.I I 12 coils with their angular position and the shift angle of the torque they generate.
  • phase shift angle p shows that the four coils shown in Figure 7 (1,4,7,10) generate a torque in phase, as well as the other 2 groups of coils (2,5,8, 1 1) and (3,6,9, 12). It can also be seen that the torque generated by these 3 coil groups are delayed by 120°. Connecting together the coils inside the same group will give the 3 phase winding shown in Figure 8.
  • a . . is: 1 coi s with their angular position the shifi angle p ⁇ , of the torque they generate, the Cartesian component shifi angles (p-1) ⁇ , and ⁇ +1) a t of the force they generate.
  • the analytical tool developed in this work is used to design a winding generating a radial force for the same motor configuration (8 poles 12 slots) as the one used in the preceding section, which presents a winding design to generate torque without generating radial force.
  • Tab. A.13 12 coi s with their angular position ⁇ * the shift angle p a, of the torque they generate, the Cartesian component shifi angles ⁇ -1) a t and ⁇ +1) ⁇ f of the force they generate.
  • Figure 11 shows that in supplying these two phases with a constant current I, two rotating radial forces in quadrature are generated.
  • Phase 1 (coils 1,-3,5,-7,9,-11):
  • Phase 2 (coils 2,-4, 6,-8,10,-12):
  • Expression (a.46) shows that the force magnitude is a function of the coil opening s. This parameter is chosen in order to maximize the radial force and also to have a winding easy to build.
  • the following Table shows that the largest force is obtained with a two slot coil opening.
  • Figures 12 and 13 show two "2 phase winding" designs that generate two radial forces in quadrature.
  • the winding with a one slot coil opening (Figure 12) is easier to build, but needs 42% more current to generate the same force magnitude as the one generated with a two slot coil opening ( Figure 13).
  • the Slot number Z corresponds to 2 groups of coils generating a force with Cartesian component term in (p-1) that are in phase, while the slot number Z 2 corresponds to 2 groups of coils generating a force with Cartesian component terms in (p+1) that are in phase (expressions (a.35) and (a.36)).
  • the generated torque will be void.
  • phase number of these windings can be changed.
  • the phase number of the winding generating torque is usually 3, but can be 2 or 5.
  • the most usual solutions for five phase spindle motors are summarized in Table VIII.
  • Table IX summarizes the motor configurations for a pair pole number p up to 6 and a slot number per pole and phase of 1 and 2.
  • Tab. A.23 motor configurations ⁇ slot number in function of the pole number 2p and the slot number per pole and per phase q) compatible with a 23 phase winding generating torque.
  • the intersection between tables VI and IX gives one configuration (2 poles 8 slots) that is compatible with a 2 phase winding generating torque and a 2 phase winding generating two radial forces in quadrature.
  • Slot number Z corresponds to 3 groups of coils generating a force with Cartesian component term in (p-1) that are in phase
  • slot number Z 2 corresponds to 3 groups of coils generating a force with Cartesian component terms in (p+1) that are in phase (expressions (a.35) and (a.36)).
  • the generated torque will be void.
  • Annex 2 presents a description of all the 3 phase winding corresponding to the above table.
  • tables VII and X The intersection between tables VII and X gives two motor configurations (4 poles 6 slots and 8 poles 18 slots) that are compatible with a 3 phase winding generating torque and a 3 phase winding generating 3 radial forces with directions separated by 120°.
  • Figure 15 shows a motor structure that allows the use of the combination of all torque winding and radial force winding solutions.
  • the inner and outer magnetic circuits have the same configuration (same pole and slot numbers), but could have different ones. That is the inner and outer magnetic rings 200, 202 have the same number of alternating poles, cooperating with slots 204 formed on either side of a central ring 206.
  • Figures 16A and 16B show an example of a motor with a slotless winding, which can be adapted to use the inventions.
  • the winding is a cylinder placed in the airgap, it is easy to place 2 windings in the same airgap as concentric cylinders.
  • This example describe, for a 6 poles slotless motor, the windings generating torque and radial force.
  • Table XII To generate torque with a 3 phase winding, only one solution corresponds to a 6 pole motor (Table XII, above).
  • This winding is composed of 18 coils.
  • Table XIII gives each of the 18 coils their angular position CC j , the phase shift angle (p c.;) of their torque, and the phase shift angle (p+1) a x and (p-1) a,- of the Cartesian components of the force generated by these coils.
  • Tab. A.32 18 calls with their angular position ⁇ , the shift anglep a ( of the torque they generate, the Cartesian component shifi angles ⁇ -1) a, and ⁇ +1) a, of the force they generate.
  • table XTJI shows that 3 coil groups generate torque that are in phase: group 1 (+l,-4.+7,-10,+13,-16), group 2: (+3,-6,+9,-12,+15,-18) and group 3 : (-2,+5,-8,+l 1,-14,+17). Connecting in series the coils inside the same group will give 3 phases generating 3 torques delayed by 120 degrees, and no radial forces.
  • Table XVI gives for the 8 coils of the first solution their angular position CCj , the phase shift angle (p a) of their torque, and the phase shift angle (p+1) ⁇ f and (p- 1) ctj of the Cartesian components of the force generated by these coils.
  • This section try to define the currents that must flow through the phases to generate a given radial force. It will be first assumed that the polar coordinates of the radial force are known, then it will be assumed that the rectangular Cartesian coordinates of the radial force are known.
  • phase currents can be determined by doing:
  • phase currents can be determined by doing:
  • phase 2 the projection of the vectors of the x and the y radial force components onto the vector of the force generated by phase 2:
  • This section tries to define the currents that must flow through a 3 phase winding to generate a given radial force.
  • the simplest way to solve this problem is to determine the 3 phase winding currents from the 2 phase winding currents calculated in the previous section. This is equivalent to determining the relationships between a sum of 2 forces in quadrature and a sum of 3 forces which directions are separated by 120°, when both sums give the same final force (Figure 20).
  • phase currents can be calculated with expressions (a.59) and (a.60).
  • Figure 21 presents a block diagram of phase 1 current determination (corresponding to expression (a.59)).
  • inputs 400, 402 are the x and y radial force components and the input 404 represents rotor position; the output 406 is the current value.
  • Means are provided for processing two trigonometric functions 410, 412, having arguments are a function of the rotor position, two multiplications 414, 416 and one addition 418 of the multiplier outputs.
  • Figure 22 presents an electronic solution which includes processing one trigonometric function and one multiplication, thereby implementing the functions of blocks 410, 414 or blocks 412, 416.
  • This approach is of course only exemplary.
  • An EPROM memory 420 is addressed with the argument of the trigonometric function. The memorized value of this function for the corresponding argument is then transferred to a Digital to Analog Converter 422 via the EPROM Data Bus 424.
  • the voltage reference input 426 of the D/A Converter based on the input radial force component 400 or 402 is then used to process the multiplication.
  • Figure 23 assumes that the motor speed stays fairly constant or has at worst a slow variation (that can be achieved with a system with a fairly large inertia). It uses a counter 440 incremented on the falling edge of an input clock 442, which frequency is proportional to the motor rotating speed ⁇ (where p is the motor pair pole number). To guarantee the synchronism, the counter is reset to a low level by applying one pulse per electric period on its reset input 444, as shown.
  • the input clock frequency can be maintained constant in constant speed applications like the spindle motor of a hard disc drive, making the solution even simpler.
  • the reset pulse can be provided by the motor driver in such a constant speed application.
  • Figure 24 presents a second solution incorporating phase delay adjustment utilizing timing signals shown in Figure 25. This solution uses two identical counters incremented with the same input clock signal 454 at input 456 or 458.
  • the first counter 450 is reset to a low level by applying one pulse per electric period on its reset input 460 utilizing reset 462 shown in Figure 25.
  • the second counter 452 is reset to a low level by applying one pulse on its reset input 464 utilizing reset 2, 466 each time the first counter value is equal to a switch programmed value 480, shown in Figure 25.
  • a magnitude comparator 470 compares the output of counter 450 with a phase delay value set by switches 472.
  • Figure 26 illustrates how the reset pulse can be provided by the motor driver.
  • the logical command [4] of one of the 6 transistors supplying the motor is used: a pulse will be generated at every raising edge of this signal (Fig. 27).
  • Figure 28 shows through a block diagram how the electronic solution presented in the previous section can be inserted in the complete system.
  • the block called "synchronous multiplier" 600 processes the 2 current consigns (i phI and i p ⁇ ) as a function of the radial force Cartesian components (F x and F y ) which are found as described below.
  • Two current amplifiers 602, 604 are then used to supply the 2 phase radial force winding 606 of the motor 608.
  • the standard motor windings 610 are also shown. Other details of this block diagram can be found in the incorporated application.
  • an input clock CK 612 with a frequency proportional to the motor speed can be generated by a function generator 614 of a known, standard design for constant speed applications as described above; a RESET signal 616 with one pulse per electrical period; this signal can be provided by the motor driver 618 as shown in Fig. 26 and 27 and is the leading edge 617 of the periodic command signal to one phase of the motor
  • any regularly repeating signal representing rotational position of the motor can be used; a switch programmed phase delay value 620 that allows a direction adjustment of the generated radial force.
  • Figure 29 shows the phase delay effect on the radial force direction and is explained more fully below.
  • Figure 29 shows how the phase delay influences the direction of the force generated by the currents flowing in the 2 phase radial force winding 606 (Fig. 28).
  • phase delay modification can be utilized to provide a 360 degree rotation of the resulting radial force.
  • the next section will present a method using the response to a rotating radial force excitation. As this method uses measurement to adjust the radial force direction, it is less sensitive to position inaccuracy. An automatic algorithm using this method has been developed.
  • This section present a radial force direction adjustment method that has been used in an hard disc drive application.
  • the spindle motor is used as an actuator to control the gyroscopic motion of the rotor 400, which is supported by two ball bearings 702, 704 (Fig. 30) on shaft 705.
  • a radial force will be applied on the magnet 706 of the rotor to suppress any unwanted motion of the disc 708 supported on the rotor.
  • This application uses two capacitive probes 800, 802 associated preferably with rotor 700 of motor 608 to measure the gyroscopic motion of the rotational axis or shaft 705. From these measures, some feedback will be calculated and applied through the radial force actuator which in this example, comprises the added windings. To obtain a stable system, it is then very important to adjust the direction of the correction force relative to the reference direction corresponding to the positions of the probes 800, 802.
  • the method uses the actuator itself to excite the gyroscopic motion with a rotating radial force as described in Figure 31.
  • the two capacitive probes 800, 802 are then used to measure the excitation response given by the angular positions ⁇ and ⁇ of the axis of rotation 900 (Fig. 32). Further details of the operation of the system of this block diagram appear in the incorporated application.
  • a comb 810 filter is used to separate the components that are synchronous with the motor speed from components that are not (called Non Repeatable Runout).
  • Figures 33 and 34 show a response measure for a forward excitation and Figures 35 and 36 show a response measured for a backward one.
  • Figures 35 and 36 show a response measured for a backward one.
  • the radial force direction adjustment can then be done in using the phase Bode plot of the a wave.
  • Figure 40 shows the effect of a phase delay on this Bode plot.
  • Figure 39 presents an ideal situation where the delay introduced by the system components is neglectable.
  • components such the current amplifiers, the capacitive probe and the comb filter introduce temporal delays corresponding to about 20 electrical degrees for the gyro frequencies ( Figure 41).
  • the synchronous multiplier 600 phase delay could be used to compensate for the temporal delay; Figure 42 shows that this is probably not practical as a backward temporal delay.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Windings For Motors And Generators (AREA)

Abstract

Un moteur à axe polyphasé à courant continu (figure 1A, 1B), qui fournit un couple (figure 1A) et une force radiale supplémentaire (F, figure 1B) dans ledit moteur, utilise les composants de l'axe (aimants et lames du stator). L'interaction entre les aimants et les courants qui parcourent les conducteurs créent le couple et la force radiale (F) nécessaires à la stabilité générale et au fonctionnement efficace du système.
PCT/US1997/004197 1997-03-19 1997-03-19 Moteur a courant continu produisant une force radiale Ceased WO1998042063A1 (fr)

Priority Applications (7)

Application Number Priority Date Filing Date Title
GB9921852A GB2337647B (en) 1997-03-19 1997-03-19 DC motor actuator to create radial force
HK00102978.2A HK1023858B (en) 1997-03-19 Dc motor actuator to create radial force
JP54045998A JP4034358B2 (ja) 1997-03-19 1997-03-19 半径方向の力を発生するｄｃモータアクチュエータ
PCT/US1997/004197 WO1998042063A1 (fr) 1997-03-19 1997-03-19 Moteur a courant continu produisant une force radiale
DE19782264T DE19782264T1 (de) 1997-03-19 1997-03-19 Gleichstrom-Motor-Aktuator zum Erzeugen einer radialen Kraft
US09/029,043 US6201322B1 (en) 1997-03-19 1997-03-19 Brushless spindle DC motor used as an actuator to create radial force
KR10-1999-7008496A KR100393858B1 (ko) 1997-03-19 1997-03-19 방사상 힘을 발생시키는 ｄｃ 모터 액추에이터

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1997/004197 WO1998042063A1 (fr) 1997-03-19 1997-03-19 Moteur a courant continu produisant une force radiale

Publications (1)

Publication Number Publication Date
WO1998042063A1 true WO1998042063A1 (fr) 1998-09-24

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Family Applications (1)

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PCT/US1997/004197 Ceased WO1998042063A1 (fr) 1997-03-19 1997-03-19 Moteur a courant continu produisant une force radiale

Country Status (5)

Country Link
JP (1) JP4034358B2 (fr)
KR (1) KR100393858B1 (fr)
DE (1) DE19782264T1 (fr)
GB (1) GB2337647B (fr)
WO (1) WO1998042063A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002007289A3 (fr) * 2000-07-16 2002-05-02 Levitronix Llc Entrainement electrique inusable et economique
EP1212826A4 (fr) * 1999-07-20 2003-12-03 Lasesys Corp Dispositif de balayage laser galvanometrique a haute efficacite de balayage
US8203246B2 (en) 2009-02-20 2012-06-19 Denso Corporation Five-phase motor with improved stator structure
CN112737254A (zh) * 2020-12-11 2021-04-30 哈尔滨理工大学 一种双转子单定子调相机

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006042539C5 (de) * 2006-09-11 2016-10-20 Gottfried Wilhelm Leibniz Universität Hannover Arbeitsspindel und Verfahren zum Betreiben einer Arbeitsspindel

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US4227107A (en) * 1977-12-05 1980-10-07 Itsuki Ban Direct current motor with double layer armature windings
US5164622A (en) * 1990-06-14 1992-11-17 Applied Motion Products, Inc. High pole density three phase motor
US5376851A (en) * 1992-05-18 1994-12-27 Electric Power Research Institute, Inc. Variable reluctance motor with full and short pitch windings
US5376852A (en) * 1990-07-19 1994-12-27 Kabushiki Kaisha Toshiba Three-phase armature winding
US5396388A (en) * 1992-02-27 1995-03-07 Censtor Corp. Compact, high-speed, rotary actuator and transducer assembly with reduced moment of inertia and mass-balanced structural overlap with drive motor and organizing method for the same
US5459383A (en) * 1991-02-07 1995-10-17 Quantum Corporation Robust active damping control system

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Publication number Priority date Publication date Assignee Title
US4774428A (en) * 1987-05-15 1988-09-27 Synektron Corporation Compact three-phase permanent magnet rotary machine having low vibration and high performance
DE69503335T2 (de) * 1994-10-28 1998-10-29 Hewlett Packard Co Ausgleich von medialen Reluktanzkräften in einem Gleichstrommotor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4227107A (en) * 1977-12-05 1980-10-07 Itsuki Ban Direct current motor with double layer armature windings
US5164622A (en) * 1990-06-14 1992-11-17 Applied Motion Products, Inc. High pole density three phase motor
US5376852A (en) * 1990-07-19 1994-12-27 Kabushiki Kaisha Toshiba Three-phase armature winding
US5459383A (en) * 1991-02-07 1995-10-17 Quantum Corporation Robust active damping control system
US5396388A (en) * 1992-02-27 1995-03-07 Censtor Corp. Compact, high-speed, rotary actuator and transducer assembly with reduced moment of inertia and mass-balanced structural overlap with drive motor and organizing method for the same
US5376851A (en) * 1992-05-18 1994-12-27 Electric Power Research Institute, Inc. Variable reluctance motor with full and short pitch windings

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1212826A4 (fr) * 1999-07-20 2003-12-03 Lasesys Corp Dispositif de balayage laser galvanometrique a haute efficacite de balayage
WO2002007289A3 (fr) * 2000-07-16 2002-05-02 Levitronix Llc Entrainement electrique inusable et economique
US6879074B2 (en) 2000-07-16 2005-04-12 Levitronix Llc Stator field providing torque and levitation
US8203246B2 (en) 2009-02-20 2012-06-19 Denso Corporation Five-phase motor with improved stator structure
CN112737254A (zh) * 2020-12-11 2021-04-30 哈尔滨理工大学 一种双转子单定子调相机

Also Published As

Publication number Publication date
GB9921852D0 (en) 1999-11-17
HK1023858A1 (en) 2000-09-22
GB2337647A (en) 1999-11-24
KR100393858B1 (ko) 2003-08-06
JP2002511228A (ja) 2002-04-09
KR20000076393A (ko) 2000-12-26
DE19782264T1 (de) 2000-05-11
GB2337647B (en) 2001-04-18
JP4034358B2 (ja) 2008-01-16

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