Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
MLJL.TI~PHASE ELECTRTC MACHYNE
WITH OFFSET MiJLTr-POLAR ELECTRIC POLE UNZTa
BACKGROUND OF THE INVF~TTZON
1. Field o~ the Invention
The invention concerns a mufti-phase electric machine
as wel_1 as a production process for such a maohine.
2, Description of the Prior Art
~n the production of mufti-phase electric machines
which are operated ~xt high currents and voltages, the insulation
of intersecting conductor lanes requi.xes increased manufacturing
expenditures. Tn order to attain high efficiency and power
densities, the proportion of the conductor in.'re3.ation to the
groove volume should be as large as possible and the proportion
of the conductor length in the wind~.ng overhang should be as
small as possir~l.e.
US-PS 4,398,112 describes a layered winding fnr disk
armatures and linear motors in which stamped conductor layers are
inserted into the grooves from the aa,r gap in direction of the
groove depth. This results in ~xery short lengths of all
conductor lanes in the winding as described in said ~;atent
document, however, because al,l conductor lengths of da.fferent
phases have different distances to the air gap, the groove volume
is completely utilised only iri single-phase machines. 5ingle-
phase machines, however, show strong variations of trrque. rn
two-phase machines ~ui.th windi.r~gs in accordance with the said
United States patent document the utilization ~at~tor o~ the
grooves would already drop to 50~, and in three-phz~se .machines to
33~.
From GB-A-1" 0~~,9, O10 a three-phase ref uctance machine
with axial ai,r gap ~.s known, the spooled stator of said machine
being arranged between two rotor disks. The number of eleck;ric
2~~~~18
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poles which are evenly distra.buted over the circumference of the
stator amounts tb three times the number of teeth in one of the
identical rotors, and a soft-magnetic rotor tooth savers one half
of the air gap surface plane which is occup~.ed by three adjacent
electric poles. Three successive electric poles belong each to
different phases, and successive electric poles cf the same phase
are wound in opposite direction to each other arid are switched in
series. The magnetic utilization of of the air gap surfa~:e plane
is here below 50~ and in spite of a large ~Uantity of winding,
only low utiliaat~.an factors are attained.
zn GB-A--945, 032 ca small, single-phase high trequer~cy
generator is described which is characterized by its extremely
flat design. A printed winding' with mea.ndev-shaped conductor
progression ~.s arranged on a mufti-polar permanent magnet ring.
Between the windings at the air gap axe soft-magnetic toGth
groups where the distance between teeth of adjacent pales ~.s
larger than the spacing of the. teeth within the poles.
Further, from Ep 0,341,867 A1, a two-phase stepping
motor is known whose winding consists of two conductor rings
which are arranged axially side-by-side. Each conductor ring is
encased by an unlaminated sheet metal housing which is toothed an
the interior surface in the radial direction toward the rotor,
the toothing of the two identical halves of the steppi.nc_t motor
being offset, against each other by 180°.
Z'he invention is based on the objective to advance the
development o~ a mufti-phase electric machine and a manufacturing
process of this machine in such a manner that high efficiencx arid
power densities with concurrent low t~J~mic losses are achieved, as
well as material-saving, easily automated and, therefore, cost--
effective production is rztade possible.
~UMMA~tY f~~' '~'~NTrON
In accordance with the invention, this objecti a is
achieved by the characteristics of claim 1. and 7.
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A machine in accordance with the invention consists of
several electric pole units, the number of phases of each. said
electric pole unit corresponding to a fraction of the number cf
phases of the machine. In the direction of movezr~ent, or in. the
direction of the gxoo~'e width respectively, the electric pole
units possess several pples of alternating polarity with the pole
pitch within one electric pole unit being constant. Tne
associated rotor or stator possesses this pole piG.ch aver' i.ts
ent7~re cl,xCUmtereriCe (or its length, respectively). The number
of phases of the machine compared to the number of phases of the
electric pole units is multiplied by arranging rigidly connected
eJ.ectric pole units which are offset against each other by a
fraction of a pole pitt~h with reference to the rotor polAs of the
machine.
These preferably single-phase or two-phase e3.ectric pole units
a.re arranged successively either in direction of the groove
depth, in direction of the gzoove or in direction of the
groove width and possess conductor lanes of a xectanc~ular cross
section, fihe conductors run in meander ehaped layers and partial.
areas within soft-magnetic bodies, said layers an6 partial areas
progressing para11e1 to the air gap and perpendicular to the
direction of movement.
In an advantageous embodiment a multi-phase electric
machine consists of identi.cr~l single-phase electric pole units,
the number of said electric pole units cQrrespanding to the
number a~ phases or a whole number muJ.tiple of it. In this
configuration the conductor ~.nsulation needs to be designed far
only a fraction of the terminal voltage, Tn machines with a
plane air gap the entire conductor assembly consists of only two
disk-shaped structural conductor designs. The grooved soft-
magnetic body can be produced as a single unit or assembled from
one structural tooth segment shape and two yoke segment shapas.
Including the groove wedges each electric pule unit consists then
only of six simple parts which, based on their large n~~mber of
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units, can be produced cost-effectively i.n an automated
production facility.
In machines with an even number of phases it is
advantageous to coordinate two electric pole units which are
offset aga~.nst each other by one ha~.f pole pitch with one rotor
disk, and the nuznlaer of rotor disks corresponds to one half the
number of phases. A three-phase machine can, howe~ter, also be
constructed from three rotor disks and si.x slectric pole units.
Larger, rotating machines, an the other hand, are
separated into several identical sector-shaped electr~.cal pole
units, in which case the interfacing grooves are of a design that
is wider by a fraction of a pole pitch. $y this symmetrical
segmentation of the machine into a,dentical electric pa~.e units
production and handling of the entz~re machine is also simplified.
The drawings present advantageous ernbodi.ments of the
invention.
RIEF DFSCRIRTIaN 0~' THE DRAWINGS
Figure 1 sP.ows a longitudinal section of a ~our-phase
disk armature with external rotor design;
Figure 2 shows six lateral views in accordance with
section A - A to F - F through the thirty-pole disk armature from
Figure 1;
Figure 3 shows three tangential. sections tYjrough the
active parts of four-phase mack~ines;
Figure 4 shows five structural designs of four-phase
linear motors;
Figure 5 shows a longitudinal section through the
gr4oved stator of a three-phase disk armature with six five-pole
sectors;
Figure 5 shows a longitudinal section through the 32--
pole rotor with permanent magnets belonging to the disk armature
from figure 1;
Fa,gure 7 shows the assembly of the tooth segments and
groove wedges fox a four-pole sector of a linear motor;
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~'iguxe 8 shows the assemb~.y of a ten-layer. conductor
stack for the sector froze Figure 7;
Figure 9 sk~ows how the conductor stack from Figure $ i,s
slid onto the teeth from Figure 7;
Figure 10 shows how the asse:nbl,ed four-pole sector a.s
stabi~.~.zed by sliding in of the yoke segments:
Figure 11 shows a profiled Conductor with variable
cross section tar a radial air gap machine;
Figure 12 shows a lcangitudlnal section through a device
for the preassembly of a four-pole sector winding of a radial air
gap machine with a profile conductor,
DETAILED DESCR'IPTTON OF THE PREFERRED EMB(JbI. MENT
Fa.gure 1 shows a longitudinal seCtion~of c~ four-phase
disk armature with external rotor design , The ~.zzternal carrier
body (1) contains a hollow space through which a coolant (2) is
c~.xculating. In the assembly, first the two inner prefabricated
electric pole units (3b, 3c) are pressed on in axial direction.
This step ensures the tangential offset of one quazter pole pitch
each by the cux~re.nt supply and current derivation (4j which ruilS
in insulated grooves (5j of the inner carrier body (1) in axial
direction to the outside. Subsequently, the two identical rotor
disks (6a, 6b) together with their inner bearings (7) and the two
outer electric pole units (3a, 3d) with their cooling bodies (8)
are pressed on in axial direction. During the axial sliding on
of the tube shaped packet shell (9) the prominences (10j of the
rotor disks and the spacer bars (11) ensure a frictional
connection that is free from play and exact posita.oning of the
rotor disks. In a final step, the two outer bearings are pressed
on.
Figure 2 shows six lateral views in accordance wa.th
sscti.on A - A to F - ~' through the thirty-pole disk armature from
Figure 1 with the haCching patterns being retained. The four
identical electric pole units (3a~3d) ax'e rotated by a fraction
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of a pale pitch in relation to the two coincidentally arranged
rotor disks (&a, 6b). The electrio pole units (3a, 3b) anc~ (3c,
3d) respectively associated with a rotor disk are rotated ir~
relation to each other by one half pole pitch. The rotation
between the two groups amounts to az~e quarter pole pitch, The
complete conductor assembly consists o~ two cor~ductox~ layers
(i3a, 13b? which are stacked on top of each other alternatingly
offset by one pole pitch. They are distinguishabJ.e by different
hatching angles and hatching densities, while the raft-magnetic
body (14) has concentric circular hatching. The conductor layer
(13a) i$ visible only in the two winding overhangs (15) where it
utilizes the recesses in the conductor i.ayer ('13a) to double its
height, The current passes in each conductor layer (13a, 13b) in
a meander pattern through the entire circumference of the mack~ine
minus one pole pitch. In this gap occurs either the current
supply and current derivation (4) for the drive or the transition
to a aonductox layer which lies adjacent in the direction of the
groove aepth. ~~he rotor disks (~a, &b) can be assembled pole
patch by poi.e pitch wish the soft or hard-maqneta.e sec"~nents being
fixed in non-magnetic mountings.
'the three tangential sections through a lineariaed
four-phase machine illustrated in Figure 3 shows the tangential
offset of the electric pole un~.ts and the progression of tile
magnetic flux in hard and soft-magnetic sec~~ner.ts respectively.
The ~.op dr~.wing of Figure 3 sho~,rs a sector corr~prising
pole pitches in which, analogous tc~ Figures 1 and 2, the
hatching and the reference numbers have been retained but the
groove depth has been reduced.
In the middle drawing of Figure 3 the field progression
of a permanent magnet e7.ectric machine without consideration of
the magnetic field of the windi:~.g is shown. The advantageous
current flow direction, for this rotor poJition is depicted by two
circular symbols each in the grooves in which a paint wi.t:~in a
Gircl.e symbolizes the'current flowing towards the viewer and a
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cross within a circle symbolizes the cuxrent flowing away from
the viewer. In order to guide the magnetic flux, slots are added
in the tangential center of the teeth of the soft.-magnetic bony
(17) , The grooves of the electric ~SO3.e unit (16a) lie opposite
the rotor pole recess. The carrespondi.ng phase is i,n the process
of comznutatiaxl and t.herefare depicted as current-less . On the
other hand, electric pole unit (lbb) c~eveJ.ops its full torque.
The electric pole units (16c) and (15d) which are also rotated by
one half pole pitch in relation to each other can make a positive
cantribuGion to the desired torque as well, The right rotating
rotor disk cons:~gts of axially magnetized rare earth magnets (7.t~)
which are fixed in their position by a fiber-reinforced mounting
(J.9) .
Tn the bottom drawing of Figure 3 the progression of
the magnetic field is shown in a four--phase reluctance machine.
The electric poJ.e units (20a-20d) are always energi~.ed when ;by a
movement of the snft~magnetic segments (21) towards the right the
magnetic resistance far the magnetic field is decreased, zn the
rotor position shown in the bottom drawing of Figure 3 the field
generated in electric pale un~.G (20b) has reached its lowest
magnetic re$istance and the current that was f):.awing up t.o this
moment in the conductors (22) is now discannerted. The magnetic
field in electric pole unit (20d) now generates a force which
moves the rotor in the direction to the right. Such reluctance
machines caz~ also be utilized as stepping rnntors.
In Figure 4 five arrangements of electric pole units in
four-phase linear motors are Shown.
Figure ~a shows a simple strucC_ural design of a foux-
phase litzear motor i n which the four elt~r~tric pole un~.ts ( 23a~
23d) are arranged sequentially in the running direction. The
spacing (24) between the identical electric pole units is one
quartex pale pitch. The spacing can lie percesved frazn the yokes
(?~). The grooved stator bar (26) which consists of saft-
magnetic material is integrated into the guide bar over its total
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length. The movable part (27) which i.s normaJ.~.y firmly connected
with the electric pole units is shown shifted upwards in order to
better clarify the three~dimensi.onal arxangemer~t.
Figure 4b shows an embodiment in which the mo~rable part
(29) possesses fourt.Een hard-magnetic segments (28) in order to
cover four three-pale electric pole units (3a) which in turn show
a distance between each other of one quarter pole pitch and in
which individual electric pole units are supplied with current
only, i.f they are at least in part energized by the perm-~nent.
field.
For movable parts which are shorter in the direction of
movement the electric po3.e units (31) - as shovin in Figure 4c -
are arranged side by side perpendicular to the running direction
or in the direction of the grooves respectively.
Tf a movable part with small overall lengthwise as well
as crosswise dimensions is desired, the arrangement shown in
Figure 4d is recomrnended in v~thich the electric pole una,ts (32)
are arranged sequer_tially in the direction of the groove depth.
The active parts of the movable part or the stator (33) protrude
skid-like between two respective electric pale units which are
offset against each other.
Figure 9e shows an arrangement with a movable part (35)
which ~.s, in relation to the electric pole Tanits (34), very
large. The active parts axe arranged laterally on the segment
bars (35) which reach horizontally into the movable, part. In
order to compensate the torque, two respective electric pale
units of the same phase are arranged in diagonally apposite
corners at the movable part.
Of the s.ix identical sectors (37a) to (39b) which are
shown in Figure 5 two respective sectors that lie opposite to
each other belong to one phase. The conductor stacks consist of
two stamped parts (40, 41) which are alternately stacked oz~ top
of each other. In the widened interfacing gxoov~e (42) the
conductors of differing phases are separated by a thicker
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insulating layer. The distance Qf the radial center ~.inas of the
r,im teeth of adjacent sectors amounts to four thirds of the
normal pole pitch which, on tk~e other ht~nd, corresponds to the
pole pitch of the movable part.
While the rotor, as shown in Figure 6, is constructed
symmetrically of thirty-two identical magnetic poles (43) which
are embedded in a plastic body (44), the stator possesses six
broader interfacing grooves (42) in order to generate differing
phases and only thirty poles (45).
Figures 7 - 1Q show the assecrbly of a faux-pole sector
for a linear motor. The depicted structural design - curved
around various axes - is also applicable in a~cial and radial air
gap machines.
Tn the assembly of the sectors, as shac~rn in Figure 7,
the tooth segments (~lfi) with insulating plates (4'7) and elastic
groove wedges (48) are joined first in tkzeir final position. The
insulating plates fill the narrow flux guiding grooves (4~) in
the center of the tooth segmezats and the groove wedges ensure the
spacing between the tooth segments and avoid air noise. 4~7ider
groove wedges (50) are required for the wider intezvacis~g
grooves.
In Figure 8 the assembly o,t a ten-layer conductor stack
(51) for the four-pole sector from Figure 7 is depicted. The five
conductor parts an the left already constitute a compact stack,
while the remaining five conductor pants are added ~,n pairs or
singly. Each conductor stack of the mufti-phase linear motor
consists of two stamped structural conductor designs, where
besides the supply and derivation conductors (52) eight normal
conductor layers (53) are insert~e~l. I~ftex sliding the conductor
layers together, they are welded together at the interface edges
(54) .
Zn F~.gure 9, the functional conductor stack (51) is
pushed onto the tooth segrnents t46?.
Finally, as shown in Figure 10, the yoke segments (55,
56) are inserted in direction t~f the groove into the tooth.
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segment ends (9:6a) which protrude from the conductor stack (51)
causing the conductor stack to be pushed against the elastic
cgrQC~ve wedges (48, 50} and achieving an assembly that is free
from play and which can be disassembled at any time again.
6esi.des the normal yoke segments (55) wider yoke segments (SS)
are required far the interface grooves to the adaacent ~.dentical
sectors of Qther phases which, as, an alternative to the noxznal
mufti-layer yoke segments, may consist of ferrite.
Alternatively to the prefabricated man-curved conductor
lanes, the partition of the mufti-phase machine iritd single-phase
electric pole units can alst~ be executed ad antageously by
profiled conductors, since the conductor progrESS~.on of s~.id
electr~.c pole unite xs non-intersecting.
in Figure 11 a rectangular profiled conductor (57) for
a radial air gap machine is shown, whose conductor cross section
is altered over predetermined longitudinal sections by a
preprogrammed rolJ.ing machine (59) prior to application of the
insulating matex~zal in a Coating facility (58). The longitudinal
Se~~.ionS with COT'A~tdn~ croSS SBCtian GOx're~pOnd to the canduGtQr
lengths of the layers which lie paralhel to the aa.x gap, thereb~~
changing the width of the conductor in proportion to the radius
at each transition to another layer.
Figure 12 shows a deva.ce (6D) in which a self-contained
four-pole sector winding (61) for a radial air gap machine is
prefabricated. The parts ref the device (62) corresponding to the
teeth are inserted into a base body (63) and possess comically
tapered ends (64) a.n order to facilitate the insertion of the
ConciuCGor. In the wider ~.nterface grocweg (65) the inclined
partial lengths of the conductor lane (66) are ~.nserted ~.nto
alignment bodies (57) which consist of an insulating high-
strength plastic. After radial pulling out of the tooth pants
( 62 ) ar_d prior to removing the prefabricated 5eCtal WlIlt~lY'lg ( 61 ) ,
said winding being rendered self-contained by a binding agent,
together with the groove insulation from the device (60) the
partial, oanductox lengths in the interfacing grooves (6S) are
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CA 02155218 2003-05-O1
once more deformed by pressing them tangentially into the solid
alignment bodies (~7). The illustration shows the partial
conductor lengths already pressed together in the left
interfacing groove (65') and not yet pressed together in the
right interfacing groove (65). 8y tangential combining of the
sector wi,n.dings (61) wh~.ah are only separated by thin insulating
plates (~8) the complete winding of the mufti-phase machine is
achieved.
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