WO2011154045A1 - Disque rotor destiné à une machine à réluctance synchrone - Google Patents

Disque rotor destiné à une machine à réluctance synchrone Download PDF

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Publication number
WO2011154045A1
WO2011154045A1 PCT/EP2010/058198 EP2010058198W WO2011154045A1 WO 2011154045 A1 WO2011154045 A1 WO 2011154045A1 EP 2010058198 W EP2010058198 W EP 2010058198W WO 2011154045 A1 WO2011154045 A1 WO 2011154045A1
Authority
WO
WIPO (PCT)
Prior art keywords
rotor
axis
radial dimension
rotor disc
disc
Prior art date
Application number
PCT/EP2010/058198
Other languages
English (en)
Inventor
Reza Rajabi Moghaddam
Original Assignee
Abb Research 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 Abb Research Ltd filed Critical Abb Research Ltd
Priority to PCT/EP2010/058198 priority Critical patent/WO2011154045A1/fr
Publication of WO2011154045A1 publication Critical patent/WO2011154045A1/fr

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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
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/24—Rotor cores with salient poles ; Variable reluctance rotors
    • H02K1/246—Variable reluctance rotors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator

Definitions

  • the present disclosure concerns a rotor disc adapted for use in a rotor of a synchronous reluctance machine. More
  • the present disclosure relates in modifying the rotor disc dimensions in order to achieve a more
  • synchronous reluctance machines include a stator with poly-phase windings forming a plurality of poles in a manner resembling a stator of an induction motor.
  • a rotor of a synchronous reluctance machine does not normally include electrical windings but has a number of poles in the form of portions with a higher magnetic permeability.
  • the rotor is formed as an anisotropic structure wherein each pole has a direction of minimum reluctance, a so-called “direct axis" or "d-axis", and a direction of maximum reluctance, a so- called “quadrature axis" or "q-axis".
  • an approximately sinusoidal magnetic flux waveform is produced in an air gap formed between the stator poles and an outer contour of the rotor.
  • the rotor will attempt to align its most magnetically permeable direction, the d-axis, to the direction of the peak flux by displacing its d-axis of minimum reluctance until alignment of the magnetic fields in the stator poles and rotor poles is obtained.
  • the alignment process results in rotary motion of the rotor at the same speed as the rotating magnetic field of the stator, i.e. at synchronous speed.
  • the air gap flux generates a torque which can be conveyed to the
  • a rotor shaft bonded to the rotor and extending through a central axis thereof.
  • the rotor includes a stack of transversally oriented rotor discs.
  • the rotor discs may be coated with magnetically non- permeable material, such as varnish, to prevent generation of an axially-oriented flow of eddy-currents between
  • the rotor must, in many cases, exhibit high structural strength to allow rotation at high speeds and withstand elevated operation temperatures over extended periods of time. At the same time, the rotor should exhibit low
  • EP 2 169 805 relates to a rotor for a synchronous reluctance machine.
  • the rotor includes rotor discs in a cut-out design.
  • the outer contours of the rotor discs are provided with magnetically insulating flux barriers at the q-axis.
  • Such a design provokes to a torque ripple and friction losses at high rotational speeds.
  • a similar reluctance machine is disclosed in US 5,418,415, which relates to a reluctance motor having a rotor core with salient poles.
  • Each salient pole of the rotor core has a shape such that the gap permeance varies in proportion to where ⁇ 2 represents an angular position with respect to the origin set to the center of a salient pole.
  • EP 1 111 755 Al relates to a synchronous reluctance machine having a rotor disc with an outer peripheral contour being circular.
  • the rotor disc comprises a strengthened stress concentration portion.
  • US 2007/0126304 Al concerns a rotating machine with
  • the rotor has its minimum radial dimension at a d-axis, and the maximum radial dimension at a q-axis, using the definitions of d- and q- axes of the present disclosure. It is to be noted that due to the permanent magnets the definitions of d- and q-axes in US 2007/0126304 Al are opposite to the definitions of the present disclosure. According to the present disclosure a d- axis shall be understood as the axis of the minimum
  • One object of the invention is to provide a reliable rotor disc for a synchronous reluctance machine such that a reliable operation of the machine is ensured even at high speeds and over long operating periods.
  • a further object of the invention is to provide a reliable rotor for a
  • the invention is based on the realization that by designing a rotor disc such that the rotor has an optimal shape in operation and not in standstill, a more reliable synchronous reluctance machine is achieved.
  • a rotor disc adapted for use in a rotor of a synchronous reluctance machine, wherein the rotor disc comprises: a disc body having a first magnetic permeability and a circumferential surface; at least one flux barrier having a second magnetic permeability lower than the first magnetic permeability, wherein the at least one flux barrier is shaped and positioned in the disc body such that at least one axis of minimum reluctance, a d-axis, and at least one axis of maximum reluctance, a q-axis, are formed; a first radial dimension of the rotor disc at a q-axis, and a second radial dimension of the rotor disc at a d-axis, wherein the first radial dimension is smaller than the second radial dimension, and wherein a difference between the first radial dimension and the second radial dimension is between 0,05% and 3% of the maximal diameter
  • the difference between the first radial dimension and the second radial dimension is between 0,1% and 2%, in particular between 0,2% and 0,9%, of the maximal diameter of the rotor disc at substantially uniform temperature of the disc body at standstill .
  • the difference between the first radial dimension and the second radial dimension is reduced in operation with respect to
  • the difference between the first radial dimension and the second radial dimension at a peripheral speed of 50 m/s is less than 70%, such as less than 50% or less than 40%, of the difference between the first radial dimension and the second radial dimension at a substantial uniform temperature of the disc body at standstill.
  • the radial dimension of the rotor disc gradually changes from the first radial dimension at the q-axis to the second radial
  • the radial dimension of the rotor disc continuously, such as
  • the at least one flux barrier is disposed radial inward of the
  • the rotor disc includes at least three flux barriers, such as four flux barriers, between the circumferential surface and a rotor disc centre at a q-axis, wherein in particular the flux barriers are spaced radial apart from each other.
  • the rotor body is free of flux barriers at a d-axis.
  • At least one permanent magnet element is disposed in a flux barrier.
  • a machine using a rotor disc with permanent magnet elements may use both the magnetic torque and the reluctance torque inherent for the rotor disc.
  • a rotor for a synchronous reluctance machine comprising at least one rotor disc according to an embodiment disclosed herein.
  • the rotor comprises at least 100 rotor discs, such as at least 150 rotor discs.
  • the number of rotor discs may depend on the torque to be generated by the machine. Further, the number of rotor discs may depend on the thickness of the rotor discs .
  • a synchronous reluctance machine comprising a stator and a rotor according to an embodiment disclosed herein .
  • the machine comprises an air gap between the circumferential surface of a rotor disc and an inner surface of the stator, the air gap at a q-axis being wider than the air gap at a d-axis.
  • the air gap at a q-axis is between 1,5 and 3 times, such as between 1,7 and 2,5 times, the air gap at a d-axis.
  • a radial dimension shall be understood as the distance extending from the rotor disc centre to the circumferential surface of the rotor disc.
  • the rotor disc centre is the rotational axis once the rotor disc is assembled onto a rotor shaft.
  • the machine as described may also operate converting kinetic energy into electrical energy i.e. as a generator. According to typical embodiments of the invention, the machine as described is suitable for operating both as a motor and a generator.
  • figure 1 shows a rotor according to one embodiment of the invention
  • figure 2 shows a rotor disc and a stator according to one embodiment of the invention.
  • a rotor 1 consists of a stack of rotor discs 100.
  • the number of rotor discs 100 is typically at least 100, more typically at least 150.
  • the rotor may include up to 500 or even 1000 rotor discs 100 depending on their thickness. Further, the number of rotor discs 100 may depend on the torque needed for a specific appliance.
  • the rotor 1 has a substantially smooth envelope surface. Especially, the rotor discs 100 do not have salient poles at the outer periphery.
  • the plurality of rotor discs 100 are brought into mutual abutment in a manner where
  • neighbouring rotor discs 100 are separated only by an intermittent thin electrically insulating layer applied as varnish.
  • the varnish layer between neighbouring rotor discs 100 prevents generation of an axial flow of eddy-currents between the rotor discs 100.
  • the typical thickness of the electrically insulating layer is smaller than 0,01 mm.
  • the varnish layer is applied to the rotor discs 100 prior to stamping or punching, and the varnish thereby functions as lubrication in the punching process and results in less wear in the punching tools.
  • the varnish is, however, not
  • FIG. 2 shows an embodiment of a rotor disc 100.
  • the rotor disc 100 includes a disc body 104 in which a central opening 102 is disposed for a rotor shaft.
  • the shape of the central opening 102 is generally circular and may have one or more additional recesses such as key-holes or salients. In many cases, the number of additional recesses or salients is equal to the number of poles of the rotor disc 100.
  • the rotor disc 100 is given anisotropic structure by alternating layers of magnetically permeable segments 106 having a high magnetic permeability, and magnetically insulating flux barriers 108 having a low magnetic
  • the flux barriers 108 are created by cutting material of the disc body 104 in the shape of longitudinal slots. It is thereby the air inside the cut-outs that functions as the flux barrier 108.
  • the rotor disc 100 is typically designed to be mechanically self-sustained. Typically the magnetically permeable
  • the segments 106 are connected by narrow tangential bridges 110 at the periphery of the rotor disc 100.
  • the tangential bridges 110 are typically formed of rotor disc material in a punching or stamping process.
  • the circumferential surface 116 includes the radial outward edge of the
  • radial bridges 112 are arranged to connect two radial adjacent magnetically permeable segments 106 in order to improve the mechanical strength of the rotor disc 100.
  • the radial bridges 112 may be omitted, or further radial bridges 112 may be added.
  • the radial bridges 112 are made of the same material as the segments 106 with the high relative magnetic permeability .
  • a magnetically permeable path formed by the radial bridges 112 is detrimental to the magnetic properties of the rotor disc 100 because the radial bridges 112 conduct magnetic flux along a q-axis. Further, the magnetically permeable path formed by the tangential bridges 110 is also
  • the bridge portions provide mechanical
  • the rotor disc 100 shown in figure 2 includes four pole sectors 114.
  • the pole sectors 114 are distributed evenly about a rotor disc centre X. Each pole covers a 90° sector of the rotor disc 100 in a four pole machine.
  • embodiments may include a smaller or larger number of poles such as two poles or six poles.
  • each pole covers a 60° sector. It is also possible to have more than six poles, for instance up to 20 poles.
  • Each pole sector 114 includes five segments 106 made of a material with a high relative magnetic permeability.
  • Each of the five magnetically permeable segments 106 has an arm- shaped form extending between two predetermined angular positions at a circumferential surface 116 of the rotor disc 100.
  • Four flux barriers 108 are intermittently disposed between the permeable segments 106 in a manner where an alternating pattern of magnetically permeable segments 106 and flux barriers 108 is formed along the q-axes of the rotor disc 100 from the central opening 102 towards the circumferential surface 116.
  • the flux barriers 108 are separated from an air gap 200 between the rotor 1 and a stator 300 by tangential bridges 110.
  • the rotor disc 100 is formed as a single unitary element fabricated by punching or stamping a metallic carrier. Each rotor disc 100 is stamped to produce a circumferential surface 116, a central opening 102 for mating to a rotor shaft, and flux barriers 108 in the form of apertures.
  • the metallic carrier may include ferromagnetic metal or alloy with a high relative magnetic permeability.
  • the rotor disc material is provided in the form of a metallic carrier of silicon iron motor steel. This material is relatively inexpensive and can be provided as carrier sheets or elongate strips with suitable dimensions for punching or stamping operations.
  • the rotor disc thickness is between 0,27 mm and 0,65 mm such as 0,50 mm, but this dimension may of course be larger or smaller depending on performance and other requirements for the rotor 1.
  • the thickness is a compromise between a thin rotor disc 100 resulting in reduced eddy-currents, and a thick rotor disc 100 resulting in reduced production costs.
  • the use of thinner rotor discs 100 involves higher costs per weight of the material, a higher number of shaping and punching processes, a higher number of assembling steps, etc.
  • the maximal diameter d of the rotor disc 100 may be between 5 cm and 50 cm. For example, the maximal diameter d may be between 12 and 40 cm.
  • the rotor disc 100 is adapted to rotate around the rotor disc centre X once assembled with further rotor discs 100 to form a rotor 1.
  • there is no preferred rotational direction i.e. the rotor disc 100 is shaped and formed symmetrically in the sense that there is no predetermined rotational direction (i.e., clock-wise or counter ⁇ clockwise) .
  • Figure 2 further shows inner surface 304 of the stator 300 with a diameter D.
  • the air gap 200 between the rotor disc 100 and the inner surface 304 of the stator 300 is designed to be as narrow as possible to provide a high torque.
  • the circumferential surface 116 of the rotor disc 100 is typically arranged as close as
  • centrifugal forces may cause the radial dimension of the rotor disc 100 at the q-axes to increase due to the weaker structure compared to the d-axes. Further, iron losses cause the temperature of the rotor disc 100 to rise.
  • the rotor shaft onto which the rotor discs 100 are arranged is cooler than the periphery of the rotor discs 100. Thus, the heat is conducted from the periphery of the rotor discs 100 towards the shaft.
  • the segments 106 separated from the shaft by the tangential or radial bridges 110, 112 are less cooled than the portions close to the d- axes. Temperature differences within the rotor discs 100 lead to thermal stress which together with the mechanical stress caused by the centrifugal force may lead to a
  • a first radial dimension Rl of the rotor disc 100 at the q- axes is smaller than a second radial dimension R2 of the rotor disc 100 at the d-axes.
  • the radial dimension of the rotor disc 100 is alternating in
  • the air gap 200 between the circumferential surface 116 of the rotor 1 and the inner surface 304 of the stator 300 is increasing when going from each of the d-axes towards respective circumferential adjacent q-axes.
  • the air gap 200 at each q-axis may be 1,5 to about 3 times the air gap 200 at the d-axes, such as about 2 times the air gap 200 at the d-axes.
  • the air gap 200 between the inner surface 304 of the stator 300 and the circumferential surface 116 of the rotor 1 at the d-axes is between 0,2 mm and 0,5 mm, and the air gap 200 at the q-axes is between about 0,4 mm to 1 mm.
  • the air gap 200 at the d-axes is between about 0,3 mm to about 0,8 mm, and the air gap 200 at the q-axes is between about 0,7 mm to about 1,5 mm.
  • the difference between the radial dimensions of the rotor disc 100 at the d-axes and at the q-axes is between about 0,1% and 2%, in particular between 0,2% and 0,9% of the maximal diameter d of the rotor disc 100.
  • the radial dimension of the rotor disc 100 gradually changes from the second radial dimension R2 at the d-axis to the first radial dimension Rl at the q-axis.
  • the radial dimension may decrease continuously from the d-axes to the q-axes such that a tangent at any point of the circumferential surface 116 touches the rotor disc 100 only at a single point.
  • the continuous decrease of the radial dimension may be constant.
  • a rotor 1 including a stack of rotor discs 100 may
  • the flux barriers 108 may be equipped with one or more magnets made of permanently magnetic material such as Neodymium Iron Boron (Nd-Fe-B) or a ferrite. If, after the introduction of permanent magnets, the main magnetic flux of the machine passes through the magnets, a person skilled in the art would probably define a d-axis direction of the resulting rotor to be the direction of the main magnetic flux passing the magnets. However, the introduction of permanent magnets does not affect the directions of minimum and maximum reluctance of a rotor disc 100, and therefore the directions of the d-axes and q-axes according to the definition of the present disclosure remain the same despite of the presence of permanent magnets.
  • Nd-Fe-B Neodymium Iron Boron

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

Abstract

La présente invention a trait à un disque rotor (100) conçu de manière à être utilisé dans le rotor d'une machine à réluctance synchrone. Le disque rotor (100) comprend un corps de disque (104) doté de barrières de flux (108), lesquelles barrières de flux (108) sont mises en forme et placées dans le corps de disque (104) de sorte qu'au moins un axe de réluctance minimale (axe d) et qu'au moins un axe de réluctance maximale (axe q) soient formés. Une dimension radiale du disque rotor (100) est plus petite à un axe q qu'à un axe d, la différence étant comprise entre 0,05 % et 3 % du diamètre maximal d du disque rotor (100).
PCT/EP2010/058198 2010-06-11 2010-06-11 Disque rotor destiné à une machine à réluctance synchrone WO2011154045A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2010/058198 WO2011154045A1 (fr) 2010-06-11 2010-06-11 Disque rotor destiné à une machine à réluctance synchrone

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2010/058198 WO2011154045A1 (fr) 2010-06-11 2010-06-11 Disque rotor destiné à une machine à réluctance synchrone

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Publication Number Publication Date
WO2011154045A1 true WO2011154045A1 (fr) 2011-12-15

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2894767A2 (fr) 2013-11-22 2015-07-15 Ge Avio S.r.l. Machine électrique ameliorée, adapté pour être couplé à une machine à fluide dynamique, et une machine à fluide dynamique correspondante.
CN105612681A (zh) * 2013-12-10 2016-05-25 宝马股份公司 具有优化的永久磁铁分布的电机
EP3082225A1 (fr) 2015-04-14 2016-10-19 Ge Avio S.r.l. Procédé de conception d'une structure de rotor d'une machine électrique synchrone à réluctance et rotor pour machine électrique à réluctance synchrone correspondant
CN107852075A (zh) * 2015-04-24 2018-03-27 株式会社东芝 同步磁阻电机
US10294949B2 (en) 2014-02-03 2019-05-21 Nuovo Pignone Srl Multistage turbomachine with embedded electric motors
US20220190657A1 (en) * 2020-12-10 2022-06-16 Volvo Car Corporation Electric machine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050140238A1 (en) * 2003-12-24 2005-06-30 Takanori Yokochi Rotor of reluctance motor
US20070126305A1 (en) * 2005-12-01 2007-06-07 Aichi Elec Co. Permanent magnet rotating machine
WO2009063350A2 (fr) * 2007-11-13 2009-05-22 Askoll P & C S.R.L. Rotor à aimants permanents pour machine électrique synchrone, en particulier pour un moteur à réluctance

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050140238A1 (en) * 2003-12-24 2005-06-30 Takanori Yokochi Rotor of reluctance motor
US20070126305A1 (en) * 2005-12-01 2007-06-07 Aichi Elec Co. Permanent magnet rotating machine
WO2009063350A2 (fr) * 2007-11-13 2009-05-22 Askoll P & C S.R.L. Rotor à aimants permanents pour machine électrique synchrone, en particulier pour un moteur à réluctance

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2894767A2 (fr) 2013-11-22 2015-07-15 Ge Avio S.r.l. Machine électrique ameliorée, adapté pour être couplé à une machine à fluide dynamique, et une machine à fluide dynamique correspondante.
CN105612681A (zh) * 2013-12-10 2016-05-25 宝马股份公司 具有优化的永久磁铁分布的电机
US10505405B2 (en) 2013-12-10 2019-12-10 Bayerische Motoren Werke Aktiengesellschaft Electric machine having a rotor with first and second permanent magnets in different regions with different temperature ranges
US10294949B2 (en) 2014-02-03 2019-05-21 Nuovo Pignone Srl Multistage turbomachine with embedded electric motors
EP3082225A1 (fr) 2015-04-14 2016-10-19 Ge Avio S.r.l. Procédé de conception d'une structure de rotor d'une machine électrique synchrone à réluctance et rotor pour machine électrique à réluctance synchrone correspondant
US10277083B2 (en) 2015-04-14 2019-04-30 Ge Avio S.R.L Method for designing a rotor structure of a synchronous reluctance electric machine, and corresponding synchronous reluctance electric machine
CN107852075A (zh) * 2015-04-24 2018-03-27 株式会社东芝 同步磁阻电机
CN107852075B (zh) * 2015-04-24 2019-07-02 株式会社东芝 同步磁阻电机
US20220190657A1 (en) * 2020-12-10 2022-06-16 Volvo Car Corporation Electric machine

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