WO2002049190A1 - Stator composite - Google Patents

Stator composite Download PDF

Info

Publication number
WO2002049190A1
WO2002049190A1 PCT/GB2001/005517 GB0105517W WO0249190A1 WO 2002049190 A1 WO2002049190 A1 WO 2002049190A1 GB 0105517 W GB0105517 W GB 0105517W WO 0249190 A1 WO0249190 A1 WO 0249190A1
Authority
WO
WIPO (PCT)
Prior art keywords
teeth
back iron
segment
stator
iron portion
Prior art date
Application number
PCT/GB2001/005517
Other languages
English (en)
Inventor
Philip Beckley
Magnus Lindenmo
Hugh J. Stanbury
Original Assignee
Cogent Power Ltd
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 Cogent Power Ltd filed Critical Cogent Power Ltd
Priority to AU2002222202A priority Critical patent/AU2002222202A1/en
Publication of WO2002049190A1 publication Critical patent/WO2002049190A1/fr

Links

Classifications

    • 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
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/14—Stator cores with salient poles
    • H02K1/146—Stator cores with salient poles consisting of a generally annular yoke with salient poles
    • H02K1/148—Sectional cores

Definitions

  • This invention relates to stators as commonly used in large scale electrical machines. More particularly, the invention provides an apparatus and method which provides improved efficiency of operation of such machines.
  • Rotating machines use laminations which, in large machines, may be made up of segments cut so as to incorporate teeth which are enclosed by windings and so-called back iron which conducts magnetic flux between the stator teeth. Such an arrangement is illustrated in Figure 1.
  • stator segments Because of the bi-directionality of flux movement it is usual to manufacture stator segments from non-oriented electrical steel, since if grain oriented steel is chosen, the flux must pass into a magnetically less favourable direction of the grain oriented steel for part of its journey.
  • non-oriented steel are less favourable than those for the magnetically most favourable or "best direction" within a grain oriented electrical steel.
  • the less favourable direction in grain oriented steel (which has generally worse magnetic properties than a non-oriented steel) may be tolerated for part of the segment.
  • such an arrangement is a severe compromise as the magnetic permeability and power loss varies hugely between the 'best' and 'orthogonal (or worst)' directions of grain oriented steel.
  • the present invention aims to provide a stator which suffers less loss and as such is more efficient in operation.
  • the present invention provides a segment for a stator comprising a back iron portion and one or more teeth characterised in that the teeth are cut separately from the back iron portion and are joined with the back iron portion and the teeth and back iron have different orientation with regard favoured magnetic direction with respect to each other.
  • the favoured magnetic direction for any gain oriented electrical grade steel will be the direction in which the steel was rolled during manufacture, this is sometimes also referred to as the "longitudinal" direction of the steel or the article (such as a tooth or back iron portion) made from the steel. In grain oriented steel, this direction will be far more dominant than that seen for a non-oriented steel. However, for non-oriented steel there may be some anisotropy that will give more favourable magnetic properties in the longitudinal direction.
  • a “segment” could in fact comprise a complete ring of back iron (or a “back iron portion” ) cut from a single sheet.
  • the back iron would be cut from a sheet of non-oriented material.
  • the invention aims to utilise optimum materials ( from a technical or an economic point of view) in both teeth and back iron. Desirably, best direction magnetic properties for both the teeth and back iron of stator is achieved, however this can inflate production costs to a level which is undesirable for some applications.
  • a combination of a good non-oriented steel in the teeth and a lower cost/quality non-oriented steel in the back iron may be used. It is to be noted, of course, that there may be circumstances where it is desirable to have a relatively higher grade material in the back iron with respect to the teeth, such arrangements are also possible in accordance with the invention.
  • mixed grades of materials may be utilised, for example grain oriented material for the teeth and non-oriented grades of steel for the back iron portion.
  • the invention since the invention utilises materials and magnetic orientations which optimise the flow of flux for a particular application of the stator, the invention permits a reduction in the total quantities of material used and thereby reduces waste material.
  • a considerable reduction in the size of the back iron needed can be achieved, this has not only waste saving advantages but also space saving advantages, allowing more flexibility in factory floor layouts where these machines are incorporated.
  • both teeth and back iron portions can be provided from grain oriented strip in ways that minimise waste of material.
  • mixed grades of materials are joined to allow the convenient transference of flux, for example by laser welding, press fit joining or bonding by other well known techniques, of either individual segments, or laminated stacks of segments, by use of various shaped joints.
  • the shape of the joint may be chosen so as to optimise the transfer between tooth and back iron whilst reducing the effects of rotational flux.
  • Suitable joint shapes may include any shape where the base of a tooth is enlarged for receiving in a narrowing recess of the back iron. It is postulated that such arrangements would assist in reducing losses as flux flow between the favoured magnetic direction of a tooth and that of the back iron. In addition, such arrangements can provide for an improved rigidity of the join between the back iron and the teeth. It is to be understood that arrangements where a protrusion from the back iron is received into a recess of a tooth is a possibility not to be excluded from the scope of the invention as defined herein, however, it is expected that such arrangements may have inferior joint strength.
  • suitable joint shapes whether they be for a tooth base received in a recess in the back iron, or a protrusion of back iron for receipt in a recess in the tooth, include, but are not strictly limited to the following; shapes with rounded or radiused edges including substantially circular, oval or ellipsoidal shapes; shapes which are substantially symmetrical about an axis substantially in line with the favoured magnetic direction of the tooth, such as dovetails and fir tree joints.
  • any joint shape which permits the interlocking of the tooth and back iron may be used, furthermore two substantially planar surfaces of a tooth and back iron may also provide the interface for a join.
  • the joint is further secured by adhesion, physical bonding or some form of welding.
  • Interlocking shapes may, optionally be bonded, but equally may rely simply on their interlocking arrangement for security of the joint.
  • Any suitable chemical or physical bonding methods may be used to secure a joint, including but not limited to welding processes such as TIG welding or laser welding.
  • the surfaces may be bonded by a chemical adhesive.
  • Teeth and back iron blanks which have been selected for optimum orientation, may be formed into a composite blank. This may be subsequently stamped or laser cut etc into the final shape of the segment.
  • a segment so manufactured is considered to comprise a segment in accordance with the present invention as claimed in the appended claims.
  • the cutting of steel to form such joints may be achieved by conventional stamping, punch or die cutting techniques or by the preparation of lamination stacks of segments by techniques such as wire spark cutting, laser cutting, e-beam or water jet cutting.
  • a coating or partial coating or small object such as a locking pin of an electrically insulating material, may be provided between the joining surfaces of the back iron and the teeth. This may assist in the reduction of eddy currents in the region surrounding the joint.
  • the inventors have found that by applying the principles of the invention, overall reductions of power loss in a machine core of up to 69% may be achieved.
  • the invention can be used to improve the permeability of a system, raising the available magnetic flux density and torque, enabling less copper to be used in the magnetising windings and a lower weight of core metal employed to procure good machine performance. There is, of course associated cost savings with these advantages.
  • Reduction in the magnetic reluctance of the stator, and hence the machine, magnetic circuit gives the machine a superior electromagnetic continuity (sometimes referred to as "electromagnetic stiffness") and lower leakage reactance.
  • Figure 1 shows a stator as is known from the prior art.
  • Figures 2a and 2b show views of a segment for a stator in accordance with the invention.
  • Figure 3 shows an embodiment of a stator according to the invention.
  • Figure 4 shows a testing apparatus as used to perform the examples and comparisons with prior art described below.
  • the stator consists of laminations which make up a back iron and teeth.
  • the laminations are typically segmented and each segment is cut to form a back iron portion and tooth portion in a single piece.
  • the back iron is relatively large. It will be appreciated that in this arrangement, the magnetic flux runs parallel to the length of a tooth prior to turning through 90 ° to run along the back iron.
  • the segment of the present invention is comprised of a number of pieces joined together.
  • a first piece BI forms the back iron portion and a plurality of additional pieces T form the teeth.
  • the teeth and back iron pieces are cut to have reciprocally shaped surfaces for joining together.
  • the end of each tooth piece is shaped at its base to fan outwards into a reciprocally shaped recess in the back iron. In this arrangement, rather than abruptly turning through 90 degrees, the magnetic flux of the system is gently bent by the curvature of the fanned base and into alignment with the favoured magnetic direction of the back iron piece.
  • a stator (shown in a perspective cross section) comprises a plurality of back iron (BI) portions and teeth (T) stacked to form laminations.
  • BI back iron
  • T teeth
  • N pairs of opposing notches
  • the notches are shaped to receive securing pins, P which, desirably are made from insulating materials. This arrangement facilitates the use of considerably simpler shaped teeth and back iron blanks. This arrangement also helps reduce eddy currents which may otherwise be greater in the joint area.
  • FIG. 3 The behaviour of various composite stators was evaluated using a purpose built laboratory test frame as shown in Figure 3.
  • a standard loss testing system comprising induction (B) and magnetising field (H) sensing coils, was used for loss measurement.
  • Various tooth and back iron stator shapes were precision cut by a spark-wire method.
  • Figure 2 shows the shape and size of a test assembly of shaped laminations. Sample packs A and B are 'teeth' able to be precisely located into the 'back iron' sample packs C and D. Sample packs E and F are simply flux closure yokes. Excitation and induction sensing windings are located so as to enwrap the teeth. An air gap (g) was introduced between the tooth ends which was able to be varied.
  • Examples 1-4 relate to composites of grain oriented (GO) electrical steel whilst examples 5- 9 relate to composites of grain oriented and non-oriented (NO) steels.
  • Other terminology to note in the tables is L for longitudinal (i.e. in parallel with rolling direction of steel), T for transverse (i.e. orthogonal to rolling direction of steel) and air gap (g).
  • the composite stator comprised grain oriented 'longitudinal (L)' teeth i.e. teeth cut in the rolling direction of the strip, and grain oriented 'transverse (T)' back iron i.e. field direction in the direction 90° to the rolling direction of the strip.
  • L grain oriented 'longitudinal
  • T grain oriented 'transverse
  • Air gaps (g) between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated.
  • the results of magnetic measurements are given in Table 1.
  • An air gap of 0J5mm was considered most realistic for the set up size and it can be seen that a nominal power loss of 75 arbitrary units was noted.
  • NA values Specific apparent power, also termed as NA values are indicated in Table 2 where it can be seen that for the conventional use of GO material, NA values noted were 20.1 arbitrary units for the 0.75 mm gap.
  • the composite stator comprised 'L' grain oriented teeth and 'T' grain oriented back iron. Air gaps between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated. The results of magnetic measurements are given in Tables 1,2.
  • the composite stator comprised grain oriented 'T' teeth and grain oriented 'L' back iron. Air gaps between the teeth in the test system of 0, 0.35mm and 0J5mm were evaluated. The results of magnetic measurements are given in Tables 1,2.
  • the composite stator comprised grain oriented 'T' teeth and grain oriented 'T' back iron. Air gaps between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated. The results of magnetic measurements are given in Table 1 ,2. In this case the loss of the core increased to 130 arbitrary units.
  • the composite stator comprised GO 'L' teeth and GO 'T' back iron. Air gaps between the model teeth in the test system of 0, 0.35mm and 0J5mm were evaluated. The results of magnetic measurements are given in Table 3,4. This is the conventional use of GO material.
  • a loss value of 75 (arbitrary units) was noted and the VA value was 20.12 (arbitrary units). This is the configuration against which the other configurations are compared.
  • the composite stator comprised NO teeth and NO back iron (all 'L'). Air gaps between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated. The results of magnetic measurements are given in Table 3,4.
  • the composite stator comprised GO 'L' teeth and GO 'L' back iron. Air gaps between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated. The results of magnetic measurements are given in Table 3,4. It can be seen that a loss value of 52 arbitrary units was achieved, the lowest noted in the composites evaluated, and that VA values were 19.72 arbitrary units.
  • the composite stator comprised GO with teeth and NO with back iron. Air gaps between the teeth in the test system of 0, 0.35mm and 0.75mm were evaluated. The results of magnetic measurements are given in Table 3,4.
  • the composite stator comprised NO 'T' teeth and NO 'L' back iron. Air gaps between the model teeth in the test system of 0, 0.35mm and 0J5mm were evaluated. The results of magnetic measurements are given in Table 3,4

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

L'invention concerne un segment de stator doté d'une partie arrière en fer BI et d'une ou plusieurs dent(s)T caractérisée(s) par le fait que les dents sont découpées séparément de la partie arrière en fer et assemblées à ladite partie arrière en fer et les dents et la partie arrière en fer présentent des propriétés magnétiques différentes et/ou une orientation magnétique l'une par rapport aux autres.
PCT/GB2001/005517 2000-12-14 2001-12-14 Stator composite WO2002049190A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002222202A AU2002222202A1 (en) 2000-12-14 2001-12-14 Composite stator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0030494A GB0030494D0 (en) 2000-12-14 2000-12-14 Mixed directionality of metal for machine teeth and back iron
GB0030494.9 2000-12-14

Publications (1)

Publication Number Publication Date
WO2002049190A1 true WO2002049190A1 (fr) 2002-06-20

Family

ID=9905076

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2001/005517 WO2002049190A1 (fr) 2000-12-14 2001-12-14 Stator composite

Country Status (3)

Country Link
AU (1) AU2002222202A1 (fr)
GB (1) GB0030494D0 (fr)
WO (1) WO2002049190A1 (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004017488A1 (fr) 2002-08-16 2004-02-26 Yamaha Hatsudoki Kabushiki Kaisha Machine electrique rotative
GB2396750A (en) * 2002-12-27 2004-06-30 Unique Product & Design Co Ltd Securing stator poles in yokes
DE102005046848A1 (de) * 2005-09-29 2007-04-05 Volkswagen Ag Wicklungskörper für eine elektrische Maschine, insbesondere Stator oder Rotor für ein magnetoelektrisches Getriebe von Kraftfahrzeugen, sowie Verfahren zur Herstellung eines derartigen Wicklungskörpers
EP2006976A1 (fr) * 2007-06-18 2008-12-24 Askoll Holding S.r.l. Moteur électrique synchrone biphasé
US7855485B2 (en) 2009-02-04 2010-12-21 TECO - Westinghouse Motor Company Air core stator installation
WO2011003718A2 (fr) * 2009-07-07 2011-01-13 Gerhard Riepl Stator et procédé de production d'un stator
US7994679B2 (en) 2009-02-04 2011-08-09 Teco-Westinghouse Motor Company Small air gap air core stator
CN105375665A (zh) * 2014-08-26 2016-03-02 张秀祥 电动机、轮毂电机及其定子与励磁单元
EP2485367A3 (fr) * 2011-02-04 2017-05-31 Honda Giken Kogyo Kabushiki Kaisha Machine rotative électrique
US10454352B1 (en) 2016-05-02 2019-10-22 Williams International Co., L.L.C. Method of producing a laminated magnetic core
WO2020106864A1 (fr) 2018-11-20 2020-05-28 Crs Holdings, Inc. Procédé de fabrication d'un stator segmenté à plusieurs matériaux pour machine électrique tournante et stator fabriqué par ledit procédé
IT202000022951A1 (it) * 2020-09-29 2022-03-29 Ducati Energia S P A Generatore a magneti permanenti per la ricarica di bordo veicolo

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995012912A1 (fr) * 1993-11-01 1995-05-11 Stridsberg Innovation Ab Moteur electrique et sa fabrication
DE19728172A1 (de) * 1997-07-02 1999-01-28 Wolfgang Hill Elektrische Maschine mit weichmagnetischen Zähnen und Verfahren zu ihrer Herstellung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995012912A1 (fr) * 1993-11-01 1995-05-11 Stridsberg Innovation Ab Moteur electrique et sa fabrication
DE19728172A1 (de) * 1997-07-02 1999-01-28 Wolfgang Hill Elektrische Maschine mit weichmagnetischen Zähnen und Verfahren zu ihrer Herstellung

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1536542A1 (fr) * 2002-08-16 2005-06-01 Yamaha Hatsudoki Kabushiki Kaisha Machine electrique rotative
EP1536542A4 (fr) * 2002-08-16 2007-05-09 Yamaha Motor Co Ltd Machine electrique rotative
WO2004017488A1 (fr) 2002-08-16 2004-02-26 Yamaha Hatsudoki Kabushiki Kaisha Machine electrique rotative
GB2396750A (en) * 2002-12-27 2004-06-30 Unique Product & Design Co Ltd Securing stator poles in yokes
DE102005046848A1 (de) * 2005-09-29 2007-04-05 Volkswagen Ag Wicklungskörper für eine elektrische Maschine, insbesondere Stator oder Rotor für ein magnetoelektrisches Getriebe von Kraftfahrzeugen, sowie Verfahren zur Herstellung eines derartigen Wicklungskörpers
EP2006976A1 (fr) * 2007-06-18 2008-12-24 Askoll Holding S.r.l. Moteur électrique synchrone biphasé
US7719155B2 (en) 2007-06-18 2010-05-18 Askoll Holding S.R.L. Two-phase synchronous electric motor with permanent magnets for mechanical priming washing pumps of dishwashers and similar washing machines
US7994679B2 (en) 2009-02-04 2011-08-09 Teco-Westinghouse Motor Company Small air gap air core stator
US7855485B2 (en) 2009-02-04 2010-12-21 TECO - Westinghouse Motor Company Air core stator installation
WO2011003718A2 (fr) * 2009-07-07 2011-01-13 Gerhard Riepl Stator et procédé de production d'un stator
WO2011003718A3 (fr) * 2009-07-07 2011-10-13 Gerhard Riepl Stator et procédé de production d'un stator
EP2485367A3 (fr) * 2011-02-04 2017-05-31 Honda Giken Kogyo Kabushiki Kaisha Machine rotative électrique
CN105375665A (zh) * 2014-08-26 2016-03-02 张秀祥 电动机、轮毂电机及其定子与励磁单元
US10454352B1 (en) 2016-05-02 2019-10-22 Williams International Co., L.L.C. Method of producing a laminated magnetic core
WO2020106864A1 (fr) 2018-11-20 2020-05-28 Crs Holdings, Inc. Procédé de fabrication d'un stator segmenté à plusieurs matériaux pour machine électrique tournante et stator fabriqué par ledit procédé
US11527927B2 (en) 2018-11-20 2022-12-13 Crs Holdings, Llc Method of making a multi-material segmented stator for a rotating electric machine and a stator made by said method
IT202000022951A1 (it) * 2020-09-29 2022-03-29 Ducati Energia S P A Generatore a magneti permanenti per la ricarica di bordo veicolo
WO2022070018A1 (fr) * 2020-09-29 2022-04-07 Ducati Energia S.P.A. Générateur à aimant permanent destiné à la charge embarquée d'un véhicule

Also Published As

Publication number Publication date
AU2002222202A1 (en) 2002-06-24
GB0030494D0 (en) 2001-01-24

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