EP2489112A2 - A rotor of an electric machine - Google Patents

A rotor of an electric machine

Info

Publication number
EP2489112A2
EP2489112A2 EP10776394A EP10776394A EP2489112A2 EP 2489112 A2 EP2489112 A2 EP 2489112A2 EP 10776394 A EP10776394 A EP 10776394A EP 10776394 A EP10776394 A EP 10776394A EP 2489112 A2 EP2489112 A2 EP 2489112A2
Authority
EP
European Patent Office
Prior art keywords
rotor
permanent magnets
control winding
rotor core
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10776394A
Other languages
German (de)
French (fr)
Inventor
Sören NYMAN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wartsila Finland Oy
Original Assignee
Wartsila Finland Oy
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 Wartsila Finland Oy filed Critical Wartsila Finland Oy
Publication of EP2489112A2 publication Critical patent/EP2489112A2/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • H02K21/02—Details
    • H02K21/04—Windings on magnets for additional excitation ; Windings and magnets for additional excitation
    • H02K21/042—Windings on magnets for additional excitation ; Windings and magnets for additional excitation with permanent magnets and field winding both rotating
    • 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
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
    • H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect
    • H02K1/2773—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect consisting of tangentially magnetized radial magnets

Definitions

  • the present invention relates to a rotor of an electrical machine. More specifically, the invention relates to a permanent magnet rotor of an electrical machine and to a controlling method of electrical machine.
  • US2006103251A discloses a permanent magnet rotating electric-machine comprising a stator provided with a plurality of windings, and a rotor in which magnets are disposed in slots formed in a rotor core along an outer circumference thereof.
  • the rotor core is fixed on a rotary shaft rotating inside the stator.
  • a rotor comprises a rotor core, slots in which permanent magnets are disposed and a plurality of damper windings circumferentially disposed outside the magnets.
  • JP8251848A discloses a rotor of a permanent magnet type synchronous rotary machine. Permanent magnet inserting holes are provided in the equal pitch in the axial direction in the external circumference side of the rotor core. A drain hole for preventing leakage magnetic flux is provided between the permanent magnet inserting holes. The permanent magnets in different adjacent poles are inserted into the permanent magnet inserting holes.
  • a rotor of the permanent magnet type synchronous rotary machine is constituted by providing a means for changing distribution of magnetic flux in the axial direction.
  • a secondary conductor is buried in the drain hole 3 and both ends of such conductor are connected with a short-circuit ring Short description of invention
  • the objective of the invention is to provide a rotor where magnetic flux leakage can be controlled.
  • the objective will be achieved as presented in the independent claims. Preferred embodiments are presented in dependent claims.
  • a rotor according to the invention comprises a control winding.
  • the control winding is arranged at respective positions of the rotor of a radial flux electric machine, where leakage magnetic flux between magnetic poles is liable to be generated and current provider to provide current to the control winding in order to control leakage magnetic flux between magnetic poles.
  • the control windings are positioned at region of intersection of adjacent magnetic poles.
  • the intersection region may be at intersection between adjacent magnetic poles or rectilinear to intersection line between adjacent magnetic poles.
  • the permanent magnets may be arranged at equal intervals in radius direction with respect to a rotor core and the control winding is positioned between the permanent magnet and outer circumference of the rotor.
  • the permanent magnets are arranged in slope angle in respect to a radius direction of the rotor core such that permanent magnets are in array, for example in star-shaped array.
  • the electrical machine comprises stator, a rotor equipped with permanent magnets and control winding, and current provider to provide current to the control winding.
  • Direction and amount of current in the control winding can be controlled. This allows to:
  • the invention provides rotor where leakage magnetic fluxes, phenomenon occurring between the magnetic poles of each of the permanent magnets of the rotor, can be controlled.
  • FIGS. 1A, 2A and 3A illustrates an electrical machine according to the invention
  • FIGS 1 B, 2B and 3B are partial views from figures 1A, 2A and 3A;
  • FIGS 4 and 5 are partial views according to other embodiments of the invention.
  • Figure 1A, 2A and 3A illustrates an electrical machine 2 comprising a stator 3 and a rotor 4.
  • the stator 3 with stator winding is disposed in spaced relationship to said rotor, with an air gap 7 formed between the rotor 4 and the stator 3.
  • Permanent magnets 12 are arranged at equal intervals in radius direction with respect to a rotor core 13.
  • a control winding 14 is positioned between the permanent magnet 12 and outer circumference of the rotor 4.
  • the permanent magnets 12 are positioned to extend towards to outer periphery of the rotor core 13.
  • the rotor core is configured to form a circumferential structure 40 between the permanent magnets 12 and outer periphery of the rotor core 13.
  • the circumferential structure 40 is an uninterrupted path in the tangential direction of the rotor core 13, peripheral in relation to the permanent magnets. This circumferential structure holds permanent magnets in place when the rotor 4 rotates and also provides a position where the control windings 40 can be attached close to the end of the permanent magnet 40.
  • Excitation current of the control winding 14 is controlled by a controller 20, for example by an automatic voltage regulator.
  • the controller 20 is located outside rotor.
  • the controller 20 is arranged to control the direction and the amount of current supplied to control winding 14.
  • Excitation current is transferred to the rotor 4 by means of either slip rings 21 or a rotating exciter (reference number 22 in figure 3) arranged on the shaft 8 of the rotor 4.
  • the rotor 4 can also be mounted directly on the prime mover or driven machine, which means that there is no need for a shaft 8. In that case the rotating exciter 22 may be fixed to the rotor core (see figure 3A).
  • Intermediate terminal voltage levels can be achieved with intermediate excitation currents between the extreme levels.
  • Figures 1A and 1 B illustrate the rotor 4 in passive mode (no current in the control winding).
  • Figure 1 B is a partial view D from figure 1A. Part of the magnetic flux MF passes through the back iron located between the permanent magnet 12, with a south pole S and a north pole N, and the periphery of the rotor 4.
  • the magnetic leak ML forms a closed magnetic circuit between poles S (South) an N (North) inside the rotor only, which means that only a part of the magnetic flux MF passes the stator, and resulting terminal voltage is at it's intermediate level.
  • Reference number 40 denotes to a intersection region between adjacent magnetic poles where the control winding 14 is located. The intersection region 40 may be considered as an extension to an intersection line between adjacent magnetic poles, as illustrated in figure 1 B.
  • FIGS. 2A and 2B illustrate the rotor 4 in active mode.
  • Maximum excitation current in the control winding 14 leads to maximum excitation and maximum terminal voltage, because flux caused by the control winding passes the stator.
  • an excitation current flows in the control winding 14 a magnetic field in the opposite direction to the magnetic leak is created, according to the equation
  • H is the magnetic field force
  • / is the current in the conductor
  • r is the distance from the conductor.
  • the magnetic flux density, B is dependent on the material, and is expressed in table form for the specific material.
  • Reference number 130 denotes to hollow part of the rotor 4.
  • Rotor 4 can be attached to shaft 8, for example, with end plates (not disclosed). Hollow part, which reduces weight of the rotor 4, is possible to construct when permanent magnets are positioned as disclosed in figures.
  • Figures 3A and 3B illustrate the rotor 4 in another active mode, i.e. de-excitation mode.
  • Minimum excitation is achieved when the current in the control winding flows in the opposite direction, which weakens the magnetic field produced by the permanent magnets by creating a de-excitation magnetic field (denoted by DMF in figure 3B) with the opposite direction, i.e. de-excitation. This leads to minimum terminal voltage.
  • the rotor 4 of the electrical machine can be constructed for excitation control in two directions, excitation according to Figure 2A, and de-excitation according to Figure 3A.
  • This bi-directional excitation control has an advantage in that the range of resulting terminal voltages can be more extensive.
  • Bi-directional excitation control in synchronous generator for example, can be provided by sliprings or with separate exciters with separate diode bridges for positive and negative excitation current.
  • the rotor 4 of the electrical machine can also be constructed for excitation control in only one direction, either excitation according to Figure 2A, or de-excitation according to Figure 3A.
  • the mounting of the rotor 4 can be carried out with conventional bearings, but direct mounting on the prime mover or the driven machine is also possible thanks to the light and potentially short rotor construction.
  • Figures 4 and 5 illustrate a part of the rotor 4, where the permanent magnets 12 are arranged in slope angle in respect to a radius direction of the rotor core such that permanent magnets 12 are in array, for example in star-shaped array.
  • a control winding 14 is positioned between the permanent magnet 12 and outer circumference of the rotor 4.
  • the control winding 14 is positioned in a cavity 140 formed in the outer periphery of the rotor core 13.
  • Figures 4 and 5 also show that hollow part 130 of the rotor core is limited to permanent magnet 12. This way, the amount of iron of the rotor core is reduced at inner part of the rotor and magnetic flux leakage of the permanent magnets can be limited at inner part of the rotor, i.e.
  • Figure 5 illustrates an embodiment, wherein the control winding 14 is positioned in a cavity 140 formed in the outer periphery of the rotor core 13. Cavity 140 is formed to hold an support means 141 , for example, a plate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

The invention relates to a rotor (4) of an electric machine. The rotor (4) comprises a plurality of permanent magnets (12) embedded in a rotor core (13) and arranged in radial direction for flux concentration. The rotor further comprises a winding (14) arranged at respective positions of the rotor (10) where leakage of the magnetic flux around one magnet tip is generated, and a power supply (20, 21, 22) to provide current to control the winding (14) to control the leakage flux.

Description

A ROTOR OF AN ELECTRICAL MACHINE
Field of technology
The present invention relates to a rotor of an electrical machine. More specifically, the invention relates to a permanent magnet rotor of an electrical machine and to a controlling method of electrical machine.
Prior art
In the prior art in which permanent magnets are regularly arranged over the whole circumference of a rotor core, a satisfactory magnetic flux distribution is hard to obtain.
US2006103251A discloses a permanent magnet rotating electric-machine comprising a stator provided with a plurality of windings, and a rotor in which magnets are disposed in slots formed in a rotor core along an outer circumference thereof. The rotor core is fixed on a rotary shaft rotating inside the stator. A rotor comprises a rotor core, slots in which permanent magnets are disposed and a plurality of damper windings circumferentially disposed outside the magnets.
JP8251848A discloses a rotor of a permanent magnet type synchronous rotary machine. Permanent magnet inserting holes are provided in the equal pitch in the axial direction in the external circumference side of the rotor core. A drain hole for preventing leakage magnetic flux is provided between the permanent magnet inserting holes. The permanent magnets in different adjacent poles are inserted into the permanent magnet inserting holes. A rotor of the permanent magnet type synchronous rotary machine is constituted by providing a means for changing distribution of magnetic flux in the axial direction. Moreover, a secondary conductor is buried in the drain hole 3 and both ends of such conductor are connected with a short-circuit ring Short description of invention
The objective of the invention is to provide a rotor where magnetic flux leakage can be controlled. The objective will be achieved as presented in the independent claims. Preferred embodiments are presented in dependent claims.
A rotor according to the invention comprises a control winding. The control winding is arranged at respective positions of the rotor of a radial flux electric machine, where leakage magnetic flux between magnetic poles is liable to be generated and current provider to provide current to the control winding in order to control leakage magnetic flux between magnetic poles.
The control windings are positioned at region of intersection of adjacent magnetic poles. The intersection region may be at intersection between adjacent magnetic poles or rectilinear to intersection line between adjacent magnetic poles.
The permanent magnets may be arranged at equal intervals in radius direction with respect to a rotor core and the control winding is positioned between the permanent magnet and outer circumference of the rotor.
According to one aspect of the invention the permanent magnets are arranged in slope angle in respect to a radius direction of the rotor core such that permanent magnets are in array, for example in star-shaped array.
The electrical machine comprises stator, a rotor equipped with permanent magnets and control winding, and current provider to provide current to the control winding. Direction and amount of current in the control winding can be controlled. This allows to:
1 ) magnify the magnetic flux leakage, or
2) neutralize the magnetic flux leakage, or
3) create a magnetic flux in a direction opposite to the flux leakage.
The invention provides rotor where leakage magnetic fluxes, phenomenon occurring between the magnetic poles of each of the permanent magnets of the rotor, can be controlled. List of drawings
In the following, the invention is described in more detail by reference to the enclosed drawings, where
figures 1A, 2A and 3A illustrates an electrical machine according to the invention;
figures 1 B, 2B and 3B are partial views from figures 1A, 2A and 3A; and
figures 4 and 5 are partial views according to other embodiments of the invention.
Detailed description of the drawings
Figure 1A, 2A and 3A illustrates an electrical machine 2 comprising a stator 3 and a rotor 4. The stator 3 with stator winding is disposed in spaced relationship to said rotor, with an air gap 7 formed between the rotor 4 and the stator 3.
Permanent magnets 12 are arranged at equal intervals in radius direction with respect to a rotor core 13. A control winding 14 is positioned between the permanent magnet 12 and outer circumference of the rotor 4. The permanent magnets 12 are positioned to extend towards to outer periphery of the rotor core 13. The rotor core is configured to form a circumferential structure 40 between the permanent magnets 12 and outer periphery of the rotor core 13. The circumferential structure 40 is an uninterrupted path in the tangential direction of the rotor core 13, peripheral in relation to the permanent magnets. This circumferential structure holds permanent magnets in place when the rotor 4 rotates and also provides a position where the control windings 40 can be attached close to the end of the permanent magnet 40.
Excitation current of the control winding 14 is controlled by a controller 20, for example by an automatic voltage regulator. The controller 20 is located outside rotor. The controller 20 is arranged to control the direction and the amount of current supplied to control winding 14. Excitation current is transferred to the rotor 4 by means of either slip rings 21 or a rotating exciter (reference number 22 in figure 3) arranged on the shaft 8 of the rotor 4. The rotor 4 can also be mounted directly on the prime mover or driven machine, which means that there is no need for a shaft 8. In that case the rotating exciter 22 may be fixed to the rotor core (see figure 3A). Intermediate terminal voltage levels can be achieved with intermediate excitation currents between the extreme levels.
Figures 1A and 1 B illustrate the rotor 4 in passive mode (no current in the control winding). Figure 1 B is a partial view D from figure 1A. Part of the magnetic flux MF passes through the back iron located between the permanent magnet 12, with a south pole S and a north pole N, and the periphery of the rotor 4.
In passive mode, the magnetic leak ML forms a closed magnetic circuit between poles S (South) an N (North) inside the rotor only, which means that only a part of the magnetic flux MF passes the stator, and resulting terminal voltage is at it's intermediate level. Reference number 40 denotes to a intersection region between adjacent magnetic poles where the control winding 14 is located. The intersection region 40 may be considered as an extension to an intersection line between adjacent magnetic poles, as illustrated in figure 1 B.
Figures 2A and 2B illustrate the rotor 4 in active mode. Maximum excitation current in the control winding 14 leads to maximum excitation and maximum terminal voltage, because flux caused by the control winding passes the stator. When an excitation current flows in the control winding 14, a magnetic field in the opposite direction to the magnetic leak is created, according to the equation
H (1 )
2πτ
where H is the magnetic field force, / is the current in the conductor, and r is the distance from the conductor. The magnetic flux density, B, is dependent on the material, and is expressed in table form for the specific material. Reference number 130 denotes to hollow part of the rotor 4. Rotor 4 can be attached to shaft 8, for example, with end plates (not disclosed). Hollow part, which reduces weight of the rotor 4, is possible to construct when permanent magnets are positioned as disclosed in figures.
Figures 3A and 3B illustrate the rotor 4 in another active mode, i.e. de-excitation mode. Minimum excitation is achieved when the current in the control winding flows in the opposite direction, which weakens the magnetic field produced by the permanent magnets by creating a de-excitation magnetic field (denoted by DMF in figure 3B) with the opposite direction, i.e. de-excitation. This leads to minimum terminal voltage.
The rotor 4 of the electrical machine can be constructed for excitation control in two directions, excitation according to Figure 2A, and de-excitation according to Figure 3A. This bi-directional excitation control has an advantage in that the range of resulting terminal voltages can be more extensive. Bi-directional excitation control in synchronous generator, for example, can be provided by sliprings or with separate exciters with separate diode bridges for positive and negative excitation current.
The rotor 4 of the electrical machine can also be constructed for excitation control in only one direction, either excitation according to Figure 2A, or de-excitation according to Figure 3A.
The mounting of the rotor 4 can be carried out with conventional bearings, but direct mounting on the prime mover or the driven machine is also possible thanks to the light and potentially short rotor construction.
Figures 4 and 5 illustrate a part of the rotor 4, where the permanent magnets 12 are arranged in slope angle in respect to a radius direction of the rotor core such that permanent magnets 12 are in array, for example in star-shaped array. A control winding 14 is positioned between the permanent magnet 12 and outer circumference of the rotor 4. The control winding 14 is positioned in a cavity 140 formed in the outer periphery of the rotor core 13. Figures 4 and 5 also show that hollow part 130 of the rotor core is limited to permanent magnet 12. This way, the amount of iron of the rotor core is reduced at inner part of the rotor and magnetic flux leakage of the permanent magnets can be limited at inner part of the rotor, i.e. at side which is closer to axis of rotation. Figure 5 illustrates an embodiment, wherein the control winding 14 is positioned in a cavity 140 formed in the outer periphery of the rotor core 13. Cavity 140 is formed to hold an support means 141 , for example, a plate.
The benefits of the proposed solution compared to conventional permanent magnet electrical machines can be listed as follows:
- eliminated need for external equipment for voltage control, such as power electronics and capacitor banks
- straight-forward, rigid rotor construction
- short-circuit power capabilities due to eliminated power electronics
Compared to conventional synchronous wound rotor machines, the proposed solution offers numerous advantages:
- higher efficiency due to:
- reduced excitation current
- lower frictional losses due to a smooth rotor surface (minimum need for rotor cooling) - eliminated bearing losses if mounted directly on the prime mover or driven machine
- straight-forward, rigid rotor construction
- opportunity to raise the peripheral speed, and thereby achieve a both energy-efficient and cost-efficient design.
It is evident from the description and examples presented above that an embodiment of the invention can be created using a variety of different solutions. It is evident that the invention is not limited to the examples mentioned in this text but can be implemented in many other different embodiments. Therefore any inventive embodiment can be implemented within the scope of the inventive idea.

Claims

Claims
1. A rotor of a radial flux electric machine, comprising:
- a plurality of permanent magnets (12) embedded in a rotor core (13), producing magnetic flux lines from one magnetic pole of the magnet to the other
characterised in that
- the permanent magnets (12) are positioned to extend towards to outer periphery of the rotor core (13),
- the rotor core is configured to form a circumferential structure between the permanent magnets (12) and outer periphery of the rotor core (13),
- a control winding (14) is positioned between the permanent magnet (12) and outer circumference of the rotor and to the permanent magnets, in position where a leakage magnetic flux between magnetic poles is liable to be generated, to effect the magnetic flux between magnetic poles of the permanent magnets, and
- a current provider (20, 21 , 22) to provide current to the control winding (14).
2. A rotor according to claim 1 , characterised in that current provider comprise sliprings (21) for supplying current to control winding.
3. A rotor according to claim 1 or 2, characterised in that the current provider comprise rotating exciter (22) for supplying current to control winding.
4. A rotor according to any previous claim, characterised in that
- control winding (14) is positioned in a cavity (140) formed in the outer periphery of the rotor core (13).
5. A rotor according to any previous claim, characterised in that
- the permanent magnets (12) are arranged at equal intervals in radius direction with respect to a rotor core (13).
6. A rotor according to any previous claim 1 - 3, characterised in that in the permanent magnets (12) are arranged in slope angle in respect to a radius direction of the rotor core (13) such that permanent magnets are in star-shaped array.
7. An electric machine, characterised in that the machine comprises rotor according to any previous claims 1 - 6.
8. An electric machine according claim 7, characterised in that the machine comprises a controller (20) for supplying current to control winding.
9. An electric machine according claim 8, characterised in that the controller (20) is arranged to control the direction and the amount of current supplied to control winding (14).
10. An electric machine according claim 9, characterised in that the controller (20) is an automatic voltage regulator.
EP10776394A 2009-10-14 2010-09-30 A rotor of an electric machine Withdrawn EP2489112A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20096061A FI20096061A0 (en) 2009-10-14 2009-10-14 ELECTRICAL MACHINE ROTOR
PCT/FI2010/050751 WO2011045467A2 (en) 2009-10-14 2010-09-30 A rotor of an electrical machine

Publications (1)

Publication Number Publication Date
EP2489112A2 true EP2489112A2 (en) 2012-08-22

Family

ID=41263477

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10776394A Withdrawn EP2489112A2 (en) 2009-10-14 2010-09-30 A rotor of an electric machine

Country Status (4)

Country Link
EP (1) EP2489112A2 (en)
CN (1) CN102549886A (en)
FI (1) FI20096061A0 (en)
WO (1) WO2011045467A2 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5502368A (en) * 1994-06-06 1996-03-26 Ecoair Corp. Hybrid alternator with voltage regulator
DE19757502A1 (en) * 1997-12-23 1999-06-24 Vlado Dr Ostovic Electric machine with permanent magnet excitation
US20060103251A1 (en) * 2002-08-09 2006-05-18 Hitachi, Ltd Rotor of permanent magnet rotating electric machine

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU687847B2 (en) * 1993-06-14 1998-03-05 Ecoair Corp. Hybrid alternator with voltage regulator
JPH08251848A (en) 1995-01-11 1996-09-27 Yaskawa Electric Corp Permanent magnet type synchronous rotating electric machine rotor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5502368A (en) * 1994-06-06 1996-03-26 Ecoair Corp. Hybrid alternator with voltage regulator
DE19757502A1 (en) * 1997-12-23 1999-06-24 Vlado Dr Ostovic Electric machine with permanent magnet excitation
US20060103251A1 (en) * 2002-08-09 2006-05-18 Hitachi, Ltd Rotor of permanent magnet rotating electric machine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2011045467A2 *

Also Published As

Publication number Publication date
CN102549886A (en) 2012-07-04
WO2011045467A3 (en) 2011-09-22
FI20096061A0 (en) 2009-10-14
WO2011045467A2 (en) 2011-04-21

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