WO1991009449A1 - Moteur electrique a large entrefer, sans balais et sans fente - Google Patents

Moteur electrique a large entrefer, sans balais et sans fente Download PDF

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Publication number
WO1991009449A1
WO1991009449A1 PCT/US1990/007517 US9007517W WO9109449A1 WO 1991009449 A1 WO1991009449 A1 WO 1991009449A1 US 9007517 W US9007517 W US 9007517W WO 9109449 A1 WO9109449 A1 WO 9109449A1
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WO
WIPO (PCT)
Prior art keywords
motor
winding
power
coil
field
Prior art date
Application number
PCT/US1990/007517
Other languages
English (en)
Inventor
Daniel J. Shramo
Susan M. Benford
Original Assignee
Shramo Daniel J
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 Shramo Daniel J filed Critical Shramo Daniel J
Publication of WO1991009449A1 publication Critical patent/WO1991009449A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/04—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of windings, prior to mounting into machines
    • H02K15/0435—Wound windings
    • H02K15/0464—Lap windings
    • H02K15/0471—Lap windings manufactured by flattening a spiral winding
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • H02K11/33—Drive circuits, e.g. power electronics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
    • 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
    • H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
    • H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/28—Layout of windings or of connections between windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/173—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings
    • H02K5/1732—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings radially supporting the rotary shaft at both ends of the rotor
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/18—Casings or enclosures characterised by the shape, form or construction thereof with ribs or fins for improving heat transfer

Definitions

  • the invention relates generally to electromechanical devices such as electrical motors, generators and the like and, more particularly to slotless, brushless, large air-gap electrical motors.
  • Slotless, brushless, large air-gap motors also are relatively inefficient. Some inefficiences are due to hysteresis and eddy current losses as well as other losses that typically are dissipated as heat. Another exemplary inefficiency is the limitation on use with only one type of input electrical energy, namely either from a direct current or an alternating current power supply. Improving the efficiency of such motor and permitting its use with both types of power supplies interchangeably, would allow the motors to more readily be used in general and would expand the market for such motors.
  • a motor for instance, it would be desirable for such a motor to be used in an appliance, such as a hand drill, that would be able to run less hot than a conventional hand drill and that also either could be plugged into a wall outlet or alternatively could be powered by a battery pack.
  • the invention relates to improvements in slotless, brushless, large air gap motors. Such improvements concern efficiency of operation, ease of manufacturing, and versatility.
  • the invention also relates to a commutation scheme and to a versatile electronic control package that can be used to control several (preferably any) motors designed in accordance with the commutation scheme of the invention, regardless of torque and horsepower characteristics.
  • Another object is to minimize the amount of coil wiring necessary to drive the motor. Another object is to provide a commutation scheme that allows a common set of control electronics to be used for any size motor, which permits the control electronics to be an integral part of the motor assembly.
  • a further object is to provide a variable speed motor in which the speed is determined by modulating the pulse width of the applied power.
  • a slotless, brushless, large air-gap electric motor includes a stator having a field winding and field backiron; the field winding having a number of successively offset polygonal shaped turns so as to provide a substantially flat winding; and a rotor disposed within the stator including a shaft and a permanent magnet mounted thereon.
  • the polygonal shaped turns may be in the shape of a rectangle or a hexagonal, for example.
  • a method of making a field winding for an electrical motor includes the steps of spirally winding a wire around a polygonal shaped form; leaving a space at predetermined distances, such space having a length of such predetermined distance; collapsing two opposite sides of such form so that the wire winding will substantially flatten to fill the empty spaces with successively offset turns of such winding having the approximate polygonal shape; and wrapping the flattened winding to form a hollow cylinder.
  • an electric motor in still another aspect of the invention includes a stator having a field winding and a field backiron, the field winding configured in a Wye with a commutation switch between each leg of the Wye and ground and a power switch between the common juncture of such Wye and a power supply; a rotor disposed within the stator including a shaft and a permanent magnet mounted thereon; and an integrated circuit controlling said switches.
  • an electric motor includes a stator having a field winding and field backiron, and a rotor disposed within the stator including a shaft, a permanent magnet mounted thereon, and a pair of elements located on either side of the permanent magnet to complete a magnetic circuit between opposite poles of the permanent magnet.
  • a polyphase electric motor includes a stator having a field winding and a field backiron, the field winding configured in a
  • an electric motor includes a stator having a field winding and a field backiron, the field winding having sections for energizing by both rectified alternating current and direct current, and sections for energizing by rectified alternating current alone; and a rotor disposed within the stator including a shaft and a permanent magnet mounted thereon.
  • a method of commutating a polyphase electrical motor includes the steps of sequentially applying power to a first field winding phase; interrupting power to the first field winding phase; dissipating energy stored in the first winding phase to a second winding phase; and applying power to said second winding phase.
  • Figure 1 is an illustration of a slotless, brushless, large air gap motor according to the present invention
  • Figure 2 is an end view of the motor showing the closed end looking in the direction of arrows 2-2 of Fig. 1 ;
  • Figure 3 is a plan view of the electronics package of the present invention;
  • Figure 4 is a cross-sectional view of the motor looking in the direction of arrows 4-4 of Figure 1;
  • Figure 5 is an illustration of the magnetic fields at both ends of a typical permanent magnet rotor
  • Figure 6 is an illustration of the magnetic fields at both ends of the rotor using a magnetic permeable element of the present invention
  • Figure 7 is an oblique view of the coil winding of the present invention wound around a form
  • Figure 8 is an illustration of an exemplary coil phase winding of the present invention wired in series
  • Figure 9 is an illustration of an exemplary coil phase winding wired in parallel
  • Figure 10 is a plan view of the coil winding illustrating the phase configuration
  • Figure 11 is a partially collapsed view of the coil winding
  • Figure 12 is an illustration of the coil winding as it would be wrapped around a cylindrical core
  • Figure 13 is a cross-sectional view of one segment of each phase of the coil winding
  • Figure 14 is a cross-sectional view of the complete coil winding and permanent magnet stator
  • Figure 15 is an illustration of an alternate embodiment of a coil wrapped around a hexagonal winding form for use in the motor of Fig. 1;
  • Figure 16 is a schematic electrical circuit diagram of the motor and control circuitry of the present invention.
  • Figure 17 is a schematic view of the commutation section of the circuit of Figure 16;
  • Figure 18 is a diagram of the relative phase excitations of the respective coil sections and the supply power as a function of the angular position of the rotor of the motor of Fig. 1;
  • Figure 19 is a diagram of the pulse width modulation scheme of the present invention.
  • Figure 20 is a schematic electrical circuit diagram of the commutation scheme and power supply of an alternate embodiment of the present invention suitable for use with DC or AC power.
  • the motor 10 includes a permanent magnet rotor assembly 12 and a wound stator 14 as is conventional in slotless, brushless motors.
  • the rotor assembly 12 includes an elongate shaft 16 surrounded by a backiron core 18 which is, in turn, surrounded by a permanent magnet 20.
  • the stator assembly 14 includes a coil winding 22 having an inner diameter to provide a space sufficiently large for the rotor to be disposed therein, and a field backiron 24 surrounding the coil winding.
  • the area between the permanent magnet 20 and the inner diameter of the field backiron 24, partially filled by the coil winding 22, is referred to as the air gap 25.
  • the motor 10 further includes a housing assembly 26 having an open end section 28, middle section 30, and closed end section 32 for housing of the rotor and stator assemblies 12 and 14, respectively.
  • the stator assembly 14 is fixed within the housing assembly 26 while the rotor assembly 12 is mounted so as to permit rotation around its longitudinal axis Z.
  • the rotor assembly 12 is radially and axially fixed within the housing assembly 26 by a pair of bearings 34a, 34b mounted in the open and closed end housing sections 28, 32. Consequently, the rotor assembly 12 is free to rotate within the stator assembly 14.
  • the rotor shaft 16 extends through the open end housing section 28 for attachment to a load, and the effectuation of relative rotation of that load.
  • a thermally conductive end member 38 in contact with the closed end housing section 32 forms the end closure of the motor 10 and seals the motor from contamination.
  • the end member 38 is provided with a number of terminals 41 and 42 (Fig. 2), for connection to the power supply and motor control inputs, respectively.
  • a printed circuit board 44 (Figs. 1 and 3) upon which is mounted the control electronics (designated generally at 46) of the motor 10.
  • the circuit board 44 preferably is composed of a thin Kapton substrate upon which circuit paths and mounting pads have been printed using well known methods.
  • the control electronics circuit elements such as integrated circuits, transistors, Hall effect sensors, etc.
  • EMI shield 47 (indicated by a dashed line) may be placed between the circuit board 44 and the rotor and stator assemblies 12, 14 to reduce the deleterious affects of electrical noise on the control electronics.
  • EMI electromagnetic interference
  • the housing sections 28, 30 and 32 are made of a material with a high coefficient of thermal
  • the end member 38 is preferably designed with fins 40 or other configurations which promote heat transfer to the surrounding environment further helping to maintain relatively cool operation of the electronics 46.
  • the permanent magnet 20 of the rotor 12 is divided into a number of sections 46, called pole segments, alternatively arranged with opposite magnetic poles, north and south, facing generally in a radially outward direction. In the preferred embodiment three pole pairs, or six magnet sections, are employed.
  • the permanent magnet 20 may be constructed of six generally wedge-shaped separate magnet
  • the permanent magnet 20 includes any material(s) or construction of material(s) which will produce a pole-to-pole magnetic field as described below. Also, it will be appreciated that while the following discussion is made with 0 reference to a permanent magnet having three magnetic pole pairs, fewer or more magnetic pole pairs may be employed. For example, the invention may be used with a permanent magnet having 50 pole pairs or more, such as is typical in a stepper motor, or in a motor requiring a permanent magnet having only two pole pairs. Further, it will be appreciated that as used herein the phrases field winding, coil winding and coil are 5 equivalent phrases denoting the element or elements of the stator that produce the stator magnetic field.
  • the opposite magnetic poles of the permanent magnet 20 create a pole-to-pole magnetic circuit, a portion of which is indicated generally at 48.
  • Magnetic flux emanates from the northern pole faces 50 of the magnet 20 through the air gap 25 and the coil o winding 22 to the field backiron 24 where it follows a generally arcuate path towards a southern pole face region.
  • the magnet flux then passes back through the winding 22 and air gap 25 to the southern pole faces 52 and then through the rotor backiron 18 and back to the emanating pole faces 50.
  • the torque and horsepower characteristics of the motor 10 are determined by the reactive strengths of the magnetic fields created by the coil winding 22 and the permanent magnet 20.
  • the magnetic field strength generated by the coil 22 is a function of the number of coil turns and the amount of current flowing through the coil.
  • the magnetic field strength of the permanent magnet 20 is a function of the size of the magnet and the type of material employed.
  • the motor torque can thus be increased by adding coil turns, raising the current, using a larger permanent magnet, etc.
  • the torque characteristics of the motor 10, and thus the efficiency of the motor can also be improved by eliminating magnetic flux losses through the various components of the motor so that the magnetic field interaction between the rotor 12 and the stator 14 is increased.
  • each wire reduces eddy current flows within the wire and minimizes skin effects associated with high frequency alternating current and harmonics thereof.
  • the field backiron 24 can be manufactured using a conventional winding machine such as is used in producing field windings for conventional slotted electrical motors.
  • FIG. 5 there is shown a four pole permanent magnet rotor 53 which may be used in a typical slotless, brushless motor.
  • a magnet flux circuit 56 established between the northern and southern magnetic poles of the permanent magnet 54 (represented in the figure by phantom lines).
  • this magnetic flux circuit 56 passes through stationary conductive motor elements such as the bearings, etc., producing a fluctuating field in these elements with the associated hysteresis and eddy current losses.
  • such losses can be reduced by using a magnetically permeable flux shorting element 58 properly positioned with respect to the rotor 53 in the manner shown in Fig. 6.
  • a magnetically permeable flux shorting element 58 properly positioned with respect to the rotor 53 in the manner shown in Fig. 6.
  • Placing a high magnetically permeable element 58, such as a soft iron washer, on the rotor magnetically at either end (or both ends) of the magnet 54 shorts the magnetic flux circuit 60 and greatly reduces such losses.
  • the magnetic flux circuit 60 will be confined to the washer 58 which, since it is moving with the rotor 52, will have a constant flux.
  • FIG. 7 the first step for making a coil winding or field winding for the motor 10 is shown.
  • Such coil winding may be used for one of the phases of the motor 10, for example, the first phase 01 for a three phase motor.
  • that first step employs a continuous conductor 61 , such as an insulated copper wire, which is wound on a wiring form 62.
  • the wiring form 62 is preferably of a rectangular shape.
  • the form 62 has a height Ly which corresponds to the axial length (direction of motor axis Z) of the permanent magnet 20 and a width Lin which corresponds to the circumferential, or arcuate, length of one section 46, or pole face 50, 52 of the permanent magnet.
  • a conductor 61 suitable for use in a coil winding such as a small diameter insulated copper wire, is wrapped around the form 62 to establish plural coil segments, such as the three coil segments Al, Bl, Cl.
  • the number of coil segments corresponds to the number of pole pairs of the motor 10.
  • the first turn 63 made is in the shape of a rectangle having a height 1 ⁇ and a width L R ,,, the dimensions of which correspond to the shape of the form 62.
  • the conductor 61 is continually wrapped around the form 62 with each added turn of conductor forming an additional adjacent rectangle. • This operation is repeated until the cumulative length of the adjacent conductor turns (beginning at turn 63a and ending at turn 63b) is also equal to L R1 , thus completing the first coil section Al of coil phase 01.
  • the next coil turn 64a is then begun spaced over a distance L R1 from turn 63b of coil segment Al to start the second coil segment B x .
  • coil segment B t is formed by wrapping multiple turns of the conductor 61 around the form 62 ending at turn 64b. Coil segment is similarly made at a spacing LRj from coil segment B ⁇ Thus, three equally spaced coil segments, A lr Bj and C x , each of length L RJ and each spaced from the adjacent one a distance LR, are made. These three coil segments A,, B, and together with the spaces therebetween and the space LRi which also follows the last coil segment C, collectively will be used to form one phase of the coil winding 22 (such as that denoted as the first phase 01) having a total length of six times L R ,.
  • all phases of the coil winding 22 are wound on a single form 62 continuously with appropriate lengths of coil wire tapped to make the necessary circuit connections for each coil segment, A relie, B n and C n , of each phase of the coil.
  • each coil segment may be wound on separate respective forms 62 which have appropriate size characteristics.
  • Figures 8 and 9 show exemplary wiring configurations for representative coil turns that form the coil segments of one phase of the coil winding 22 as it would be seen when it is activated or electrically energized as when receiving electric energy.
  • the coil phase shown is electrically connected in series.
  • the first coil segment A,, of conductor wound to form the phase is tapped and connected to the power supply V, and the conductor continues unbroken until it reaches the end of the phase winding where it is tapped and attached to ground.
  • a parallel configuration for representative coil turns forming the coil segments of one phase of the coil winding 22 is shown in Figure 9.
  • each phase segment A n , B n and C n is tapped and connected to the power supply V, and the last conductor wrapping for each coil segment is tapped and connected to ground.
  • each coil segment A n , B n and C_ is actually a separate circuit or is connected as a separate circuit.
  • Each coil phase 01, 02 and 03 would be similarly wired in one of the above ways.
  • the coil 22 is connected in series or in parallel depends on the application of the motor 10 and the available power supply. In a situation where a high voltage, low ' current power source is available the coil 22 ordinarily would be wired in series to minimize power losses across the coil. In a low voltage, high current situation ordinarily it would be desirable to wire the coil in parallel to provide the appropriate potential difference across a coil segment.
  • the coil winding 22 for three phases is shown in Figure 10 looking down onto the top of the wound form 62 relative to the illustration of Figure 7 without the circuit connections described above.
  • the coil winding 22 has coil phases 01, 02 and 03, each of which is composed of coil segments A,, Bj, C,; A 2 , B 2 , C 2 ; and A 3 , B 3 , C 3 , respectively.
  • Each of the respective coil segments such as the coil segment , or the coil segment B n , etc., has a length L ⁇ and a height L R ,,.
  • the space between each coil segment is L R , and the space between adjacent coil phases (a coil phase is the assembly of coil segments , B n , etc.
  • such coil phase such as the first phase 01
  • L R the space between adjacent coil phases may be less than 1 ⁇ to provide an overlap between the wrapped coil phases and to improve torque characteristics of some motors, for example, depending on the application of the motor 10, as is known.
  • the coil 22 on the form 62 (or after it has been removed from the form 62) may be coated with a thermally conductive, electrically insulating material such as an insulating varnish which will loosely hold the wiring of the coil segments together.
  • the next step in making the coil winding 22 is to deform the winding at least partly to flatten it so that the coil segments which make up respective coil phases can be wrapped in a circumferential fashion described below.
  • the coil winding 22 is collapsed in the width dimension of the winding form 62 by rotating the bottom corners 63a, 63b of coil segment A,, 64a, 64b of coil segment Bj, etc. of the coil winding 22 counterclockwise.
  • Partially rotated and collapsed coil winding 22 and form 62 are shown in Figure 11.
  • the partially collapsed form 62 preferably is removed from within the coil winding 22. However, if the coil winding 22 has adequate dimensional integrity, the form 62 may be removed prior to the collapsing step.
  • the corners 63a, 63b, etc. are rotated a total of approximately 90 degrees, thus substantially fully flattening the coil 22. This fills in the empty spaces originally between adjacent coil segments and thus provides coil segments that have a segment length of two times L R ..
  • the effect of this collapsing action is to create a coil winding 22 with coil phases that have an alternating magnetic polarity across each distance L R _, when electrically energized.
  • the flattened coil 22 may then be coated or re-coated with a varnish or similar material which will maintain the dimensions of the coil and may also facilitate thermal conduction.
  • the finished coil 22 is then wrapped around a cylindrical core 66, as is shown in Figure 12, with an outer dimension sufficient to allow the rotor assembly 12 to rotate freely within the wrapped coil winding 22.
  • the first coil phase i still having a length of six times L R , even after having been collapsed, is intended to wrap around the core 66 exactly once. Since there is an unfilled space having a length of L R - between the first coil phase 01 and the second coil phase 02, the second coil phase will have its first coil segment A 2 offset from the first coil segment A, of coil phase 01 by one magnet pole face minus any desired overlap, as is shown in Figure 13.
  • the third coil phase 03 which, when wrapped around the core 66, will be offset from the second coil phase 02 by one magnet pole face.
  • the third coil phase 03 must have a length sufficient that it will wrap completely around the core 66, the first coil phase 01 and the second coil phase 02.
  • the increased dimensions of L R - and L R3 allows the phase segments, A n , B n and C n , of the second and third coil phases 02 and 03, respectively, to cover the arcuate length of each magnet pole face at the increased diameter, as is shown in Figure 14.
  • each further set would consequently have an increased segment length and width dimension L R . to accommodate the increasing distance from the magnet pole face.
  • Each coil phase would be electrically connected in the same way as its corresponding coil phase in the first set as described above.
  • the winding form 62 may have a hexagonal cross section, as is shown in Figure 15.
  • a coil winding 22 is produced which will come to a point at the midpoint of each of its widths. When collapsed, this coil configuration tends to lay flatter than the rectangular coil and thus may allow more coil turns to be placed in the air gap 25 of the motor 10.
  • other geometric configurations can be employed which would tend to promote a coil winding which can be collapsed flat and easily wound.
  • the coil 22 is secured within the previously formed, assembled, wound, etc. field backiron 24 such as by potting.
  • the cylindrical core 66 is removed before or after placing the coil winding 22 in the space circumscribed by the field backiron 24.
  • the field backiron 24 may be wound directly upon the completed coil winding 22, thus allowing flexibility in the dimensional tolerances of the field backiron and coil winding.
  • winding configurations described above over many recently proposed winding configurations is that the winding process can be performed using conventional winding machines and thus can be accomplished inexpensively.
  • the winding configuration of the present invention also provides a denser packing of electrical conductor turns in the air gap 25 than is possible with many conventional windings, thus permitting more coil turns in the same area and a stronger stator magnetic field.
  • the completed field winding 22 is electrically connected as in the manner shown in
  • FIGS 16 and 17 The components surrounded by the dashed line in Figure 16 constitute the electronics package 78 for the motor 10.
  • the other components are the separate coil phases 01, 02 and 03 of the coil winding 22 connected in a conventional Wye commutation configuration 80 for a three phase motor. While the field winding and commutation circuit are configured for use in a three phase motor, one with ordinary skill in the art will appreciate that the invention may be employed in any polyphase motor with similar results.
  • the electronics package 78 illustrated in Figure 16 preferably may be mounted directly in the motor housing 26, e.g. being formed and/or constructed on the printed circuit board 44.
  • the electronics package includes power circuitry 82 for providing unfiltered full wave rectified power from an alternating current power source 84; commutation and power transistors 86 for controlling current flow to and between each of the coil phases 01, l and ⁇ f ⁇ ; position sensors 88 for determining the rotor shaft 16 angular position; an integrated circuit 90 for controlling the commutation and power transistors 86; and a power conditioning circuit 92 for supplying 12 volt direct current power to the position sensors 88 and the integrated circuit 90.
  • the power circuitry 82 is a conventional rectifying circuit composed of four diodes D,, D 2 , D 3 and D 4 .
  • the conditioning circuit 92 is also a conventional circuit for converting rectified alternating current into 12 volt direct current.
  • the integrated circuit 90 uses standard logic elements available from custom IC manufacturers combined to provide the functions which will be discussed herein. Given the discussion below of the inputs, outputs and required functions of the integrated circuit, one skilled in the art could design the physical IC with reasonable effort. If desired, those functions alternatively may be carried out by discrete components, but in such case the size of the electronics package 78 may become too large for mounting within the motor housing 26.
  • the integrated circuit 90 has several outputs, including three drivers, DRIVE 1 , DRIVE 2 and DRIVE 3, to switch the commutation transistors Ql, Q2, and Q3; a switch driver PWM PWR, which preferably is pulse width modulated, to drive the power transistor QP; a common/power ground reference, COMMON; and a 12 volt DC
  • the integrated circuit 90 has several inputs, including a 12 volt DC power input; three input signals from the position sensors 88; an INHIBIT signal that may be used to latch the commutation transistors, Ql, Q2, Q3 and the power transistor QP in the nonconducting state such that the motor will not run even if power is applied to the power supply 84; and a number of motor control inputs, for example for speed, direction and power control purposes.
  • the motor control inputs are COMMON, FORWARD/REVERSE, SPEED, PHASE ADVANCE, and LOW SPEED LEVEL ADJUST. All of these signals are at low power signal logic level.
  • FORWARD/REVERSE is accomplished by opening or shorting the signal to COMMON. This can be accomplished internal to the motor for a fixed direction, clockwise/counterclockwise, application or via an external contact for reversing motor applications.
  • SPEED is provided via an external variable resistance between the speed tap and signal common to provide for variable speed through pulse width modulation of commutation power as is discussed below.
  • PHASE ADVANCE is an input from an external or internal resistor to allow adjustment of the phase to improve high speed operation.
  • LOW SPEED LEVEL ADJUST is an input from an external or an internal fixed resistor between COMMON and LOW SPEED LEVEL ADJUST to fix the maximum speed of the motor.
  • Three additional inputs, RAMP, LINEAR and EXPONENTIAL, provide a ramp, linear, or exponential function acceleration, respectively, for specialized motor applications. All of these inputs are low level logic signals from external inputs.
  • the integrated circuit 90 processes the motor control low level logic signal inputs to determine the characteristics of the output signals described above. For example, the integrated circuit 90 processes the input signal LOW SPEED LEVEL ADJUST to determine the maximum duty cycle of pulse width modulated output PWM PWR which drives the power transistor QP.
  • each coil phase 01, 02 and 03 is connected to ground through a commutation transistor, Ql, Q2 and Q3, respectively. Power is supplied to the coil Wye circuit 80 through the power transistor QP.
  • Ql, Q2 and Q3 are represented as switches, SI, S2 and S3, respectively, which couple the coil phases 01, 02 and 03 to a source of ground reference potential 94 as controlled by the integrated circuit 90.
  • the power transistor QP is represented as the switch SP which couples the commutation circuit 80 to unfiltered full wave rectified power also as controlled by the integrated circuit 90.
  • the position of the rotor 12 relative to the coil phases is detected by three position sensors 88 mounted on the circuit board 44 adjacent the rotor shaft 16 at 120 degree intervals.
  • the position sensors are preferably Hall effect sensors which sense the shaft position by sensing the rotational position of a ring magnet 95 (shown in Figure 1) on the rotor shaft 16.
  • the position sensors may be photodiodes which detect shaft position by reflecting light off of a reflective surface of the shaft 16, or other equivalent postition sensing devices.
  • the outputs of the position sensors are coupled to the integrated circuit 90 via lines 96, 97 and 98 which determines from those signals whether to open or to close the switches SP, SI, S2 and S3.
  • Figure 18 illustrates the desired state that the switches SP, SI, S2 and S3 should assume as a function of the position of the rotor shaft 16.
  • the vertical axis in Figure 18 represents the state of the switches with the higher signal indicating that the switch is closed and a lower signal indicating that the switch is open.
  • the horizontal axis represents the angular position of the rotor shaft 16 with the length of the axis totaling approximately two revolutions or 720 degrees for illustrative purposes.
  • the integrated circuit 90 uses the shaft position information obtained from the position sensors 88 along with the FORWARD/REVERSE motor control input to determine which coil phase to energize first to begin rotation of the rotor.
  • Commutation sequencing i.e., 01, 02, 03, 01 etc. or 03, 02, 01, 03 etc. is determined from the level or sign of the FORWARD/REVERSE input to produce the desired directional rotation (clockwise/counterclockwise).
  • the commutation circuit 80 is controlled through the commutation and power transistors 86 by the integrated circuit 90 in the manner illustrated in the commutation logic table below (Table 1).
  • Table 1 a numeral '1' represents a switch in the closed, or conducting position and a numeral O" represents an open or nonconducting switch.
  • each commutation phase J_>1, ⁇ 2 and 03 has an ON and an OFF cycle corresponding to whether the power switch SP is supplying current to that coil phase.
  • the power switch SP is opened and switch SI is closed (see column 1 of Table 1).
  • SI With SI closed, the residual power stored in coil phase 03 flows to coil phase ⁇ 1 when S3 is opened. This begins energizing coil phase 01 with residual energy from coil phase 03 which conventionally would have been dissipated in a bypass device as heat.
  • switch S 1 Since switch S 1 is closed just prior to S3 being opened, the inductive spike is also eliminated by allowing the current to flow from coil phase 03 to coil phase 01.
  • the power switch SP is then closed allowing current to flow to coil phase 01 to completely energize it (Table 1, Col. 2).
  • the magnetic field thus created in energized coil phase i interacts with the pole-to-pole magnetic field of the rotor 12, thus producing a reactant torque which rotates the rotor an angular distance of approximately two pole faces or 120 degrees.
  • coil phase 02 beginning its activated stage.
  • the coil phase 02 will be energized creating a magnetic field and causing the rotor 12 to rotate another 120 degrees (Col. 4).
  • the power switch SP is then opened, S3 closed and S2 opened to energize coil phase 03 with the residual power from coil phase 02 (Col. 5).
  • coil phase 03 will also create a magnetic field which interacts with the pole-to-pole magnetic field of the rotor 12 to complete one 360 degree rotation of the rotor. This sequence is repeated continuously to provide commutative power to the motor 10.
  • the power switch SP is closed allowing current to flow to the next sequential coil phase, as described above, at the same time as the commutation switch from the previously energized coil phase is opened or soon thereafter, as determined by the rotational position of the shaft.
  • the potential voltage between the commutation circuit juncture 99 and power supply 84 can be measured, and the power switch SP closed when the potential difference reaches approximately zero.
  • the commutation circuit switching described above is actually accomplished in the transistors Ql, Q2 and Q3.
  • shaft position signals 96, 97, 98 received by the IC 90 indicates the coil phase 01 is to be conducting to ground 94 (switch S 1 in Figure 17 closed) a high or active signal is output from DRIVE 1 over Line 100 to the transistor Ql .
  • the speed at which the rotor 12 will rotate may be determined by the average power applied to the coil phases pi, 02, 03 over a period of rotation.
  • the motor speed is a function of a variable or fixed signal input, e.g. which may be determined by the application in which the motor is used; and that signal is provided to the integrated circuit 90 at the input SPEED.
  • Average power to the coil phases may be determined or controlled by pulse width modulating the power supplied to the coil phases by the power transistor QP. Based on the signal supplied to the SPEED input of the integrated circuit
  • the integrated circuit determines the pulse width of the pulse width modulated signal PWM PWR which in turn drives the power transistor QP.
  • the commutation circuit 80 is actually powered by pulse width modulated power, as shown in Figure 19.
  • the basic chop frequency of the PMW PWR signal from the integrated circuit 90 is preferably in the range of 20-30 Kilohertz (Khz) although higher or lower frequencies may be employed.
  • the 20-30 Khz chop frequency is at least a decade higher than other system time constraints and thus simulates an essentially constant power input to the commutation circuit 80.
  • the percentage of the chop frequency duration during which power is applied determines the average power supplied to the commutation circuit 80.
  • the uppermost signal in Figure 19 represents an exemplary signal in which power is applied during 20 percent of the chop frequency, thus resulting in a 20 percent duty cycle.
  • the motor 10 will operate at 20 percent of its maximum speed.
  • the middle and lower signals represent exemplary duty cycles of 50 and 80 percent, respectively.
  • the speed of the motor may vary continuously between a minimum and maximum value by varying the duty cycle of the power to the commutation circuit 80.
  • the motor may also be configured to operate interchangeably with an alternating current (AC) or direct current (DC) power supply.
  • AC alternating current
  • DC direct current
  • the field winding 22 may be configured as shown in Figure 20.
  • an AC power requirement would be on the order of approximately 115 VAC at 2 amps while a DC power requirement to produce the same horsepower would be approximately 12 VDC at 18.5 amps. Consequently, to have the same output torque, which as discussed previously is a function of the number of coil turns and the applied current, each phase of the commutation circuit 80 must have two sets of windings, one for AC power and one for DC power. (The AC coils are denoted as X. and the DC coils are denoted as Y n .)
  • the commutation circuit is again configured as a Wye with each coil phase 01 , 02 and p3 having two respective switching elements SA, SB and a respective commutation transistor Ql, Q2, Q3.
  • switch SB When configured to operate on direct current, as shown in Figure 20, switch SB is open and switch SA is in position to bypass the AC coil set X-. DC power thus will flow only through the DC coil set Y n which is generally wound of a lower gauge wire than the AC coil set X pharmaceutical to handle the higher DC amperage. Power flow bypasses the AC coil set through the line 110.
  • the switch SB When configured to operate on AC power, the switch SB is closed (not shown) and the switch SA is in position to cooperate with switch SB to conduct current through the AC coil set X_. Alternating current will then flow through both the AC coil set X tract and the DC coil set Y n .
  • the power conditioning circuit 92 When configured to operate on DC power, the power conditioning circuit 92 is bypassed, thus allowing 12 volt DC power to be supplied to the integrated circuit 90 and the position sensors 88.
  • the power transistor QP In either the AC or DC configuration current flow to the commutation circuit is regulated by the power transistor QP as controlled by the integrated circuit 90.
  • the power supplied to the power transistor QP is determined by switch SM which may be positioned to supply power from the unfiltered, full wave rectified AC power supply 112 or the DC power supply 114.
  • the action of the switches SA and SB are coupled to the switch SM so that the former will automatically configure to the AC or DC power configuration depending on the position of switch SM.
  • the switch SM may be external to the motor to allow manipulation by a user or internal and manipulated such as by insertion of a power supply or power supply cord.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Windings For Motors And Generators (AREA)
  • Brushless Motors (AREA)

Abstract

L'invention se rapporte à un moteur électrique à large entrefer, sans balais et sans fente (10), qui comprend un stator (14) avec contrefer inducteur (24) et avec enroulement inducteur (22), lequel se compose de plusieurs spires polygonales successivement décalées de façon à former un enroulement plat, ainsi qu'un rotor (12) disposé à l'intérieur du stator (14) et contenant un arbre (16) sur lequel est monté un aimant permanent (20). Les spires (63a, 63b, 64a, 64b) de l'enroulement inducteur se présentent de préférence sous la forme d'un rectangle ou d'un hexagone. L'invention se rapporte également à un schéma de commutation qui assure la dissipation de l'énergie stockée dans une section de l'enroulement inducteur (22) préalablement excitée pour la transférer vers la section de l'enroulement inducteur (22) ultérieurement excitée; à un circuit intégré (90) permettant de commander n'importe quel moteur utilisant ce même schéma de commutation; à une configuration d'enroulement utilisable avec une source d'alimentation aussi bien en courant alternatif qu'en courant continu (84, 92); ainsi qu'a des éléments de mise sous tension à flux magnétiquement perméable (58) qui permettent d'augmenter l'efficacité du moteur.
PCT/US1990/007517 1989-12-15 1990-12-14 Moteur electrique a large entrefer, sans balais et sans fente WO1991009449A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US45181089A 1989-12-15 1989-12-15
US451,810 1989-12-15

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WO1991009449A1 true WO1991009449A1 (fr) 1991-06-27

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EP (1) EP0505476A1 (fr)
JP (1) JPH05505299A (fr)
WO (1) WO1991009449A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0694227A4 (fr) * 1991-09-13 1995-01-30 Faraday Energy Found Procede de fabrication d'un enroulement de moteur electrique
US6717312B1 (en) * 2001-01-03 2004-04-06 Dana Corporation Defense vehicle aiming ordinance platform having variable reluctance motor
EP1494337A2 (fr) * 2003-06-30 2005-01-05 Robert Bosch Gmbh Méthode de fabrication d'un enroulement à deux étages
EP2108213A1 (fr) * 2006-12-28 2009-10-14 Resmed Motor Technologies Inc. Procedes d'enroulement et structures pour un stator sans fentes dans un moteur
US7699687B2 (en) * 2007-03-21 2010-04-20 Oy Kwh Mirka Ab Compact electric sanding machine
FR3019698A1 (fr) * 2014-04-04 2015-10-09 Bosch Gmbh Robert Machine electrique equipee d'une tole de blindage
JP2016220410A (ja) * 2015-05-21 2016-12-22 キヤノン株式会社 ブラシレスモータおよびこれを用いた装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4686891B2 (ja) * 2001-04-20 2011-05-25 パナソニック株式会社 超音波振動子駆動モータとそのモータを使用した超音波診断装置

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US4130769A (en) * 1974-11-01 1978-12-19 Canon Kabushiki Kaisha Brushless DC motor
US4499408A (en) * 1983-06-09 1985-02-12 General Electric Company Control circuit for an electronically commutated motor, an integrated circuit for an ECM, and a method of operating an ECM
US4645961A (en) * 1983-04-05 1987-02-24 The Charles Stark Draper Laboratory, Inc. Dynamoelectric machine having a large magnetic gap and flexible printed circuit phase winding

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EP0150070A3 (fr) * 1984-01-19 1986-06-04 Papst-Motoren GmbH & Co. KG Moteur à courant continu sans collecteur à enroulement statorique sans fer
US4868970A (en) * 1985-03-08 1989-09-26 Kolimorgen Corporation Method of making an electric motor
US4733118A (en) * 1986-09-22 1988-03-22 Hhk Inc. Low damping torque brushless D.C. motor

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US3968390A (en) * 1973-03-19 1976-07-06 Hitachi, Ltd. Synchronous motor
US4130769A (en) * 1974-11-01 1978-12-19 Canon Kabushiki Kaisha Brushless DC motor
US4645961A (en) * 1983-04-05 1987-02-24 The Charles Stark Draper Laboratory, Inc. Dynamoelectric machine having a large magnetic gap and flexible printed circuit phase winding
US4499408A (en) * 1983-06-09 1985-02-12 General Electric Company Control circuit for an electronically commutated motor, an integrated circuit for an ECM, and a method of operating an ECM

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See also references of EP0505476A4 *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0694227A4 (fr) * 1991-09-13 1995-01-30 Faraday Energy Found Procede de fabrication d'un enroulement de moteur electrique
EP0694227A1 (fr) * 1991-09-13 1996-01-31 Faraday Energy Found Procede de fabrication d'un enroulement de moteur electrique
US6717312B1 (en) * 2001-01-03 2004-04-06 Dana Corporation Defense vehicle aiming ordinance platform having variable reluctance motor
EP1494337A2 (fr) * 2003-06-30 2005-01-05 Robert Bosch Gmbh Méthode de fabrication d'un enroulement à deux étages
EP1494337A3 (fr) * 2003-06-30 2006-08-02 Robert Bosch Gmbh Méthode de fabrication d'un enroulement à deux étages
US7302749B2 (en) 2003-06-30 2007-12-04 Robert Bosch Gmbh Method of making a two-layer lap winding for a multiphase electrical machine
EP2108213A1 (fr) * 2006-12-28 2009-10-14 Resmed Motor Technologies Inc. Procedes d'enroulement et structures pour un stator sans fentes dans un moteur
EP2108213A4 (fr) * 2006-12-28 2014-12-17 Resmed Motor Technologies Inc Procedes d'enroulement et structures pour un stator sans fentes dans un moteur
USRE47090E1 (en) 2006-12-28 2018-10-16 Resmed Motor Technologies Inc. Coil winding methods and structures for a slotless stator in a motor
US7699687B2 (en) * 2007-03-21 2010-04-20 Oy Kwh Mirka Ab Compact electric sanding machine
FR3019698A1 (fr) * 2014-04-04 2015-10-09 Bosch Gmbh Robert Machine electrique equipee d'une tole de blindage
JP2016220410A (ja) * 2015-05-21 2016-12-22 キヤノン株式会社 ブラシレスモータおよびこれを用いた装置

Also Published As

Publication number Publication date
EP0505476A1 (fr) 1992-09-30
JPH05505299A (ja) 1993-08-05
EP0505476A4 (fr) 1994-02-16

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