WO2022264157A1 - Rotor pour machine électrique tournante - Google Patents

Rotor pour machine électrique tournante Download PDF

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Publication number
WO2022264157A1
WO2022264157A1 PCT/IN2022/050423 IN2022050423W WO2022264157A1 WO 2022264157 A1 WO2022264157 A1 WO 2022264157A1 IN 2022050423 W IN2022050423 W IN 2022050423W WO 2022264157 A1 WO2022264157 A1 WO 2022264157A1
Authority
WO
WIPO (PCT)
Prior art keywords
region
polarity
area
rotor
magnet
Prior art date
Application number
PCT/IN2022/050423
Other languages
English (en)
Inventor
Sarmadh Ameer Shafi Khan
Vamsi Krishna Balla
Giri VENKATRAMANAN
Ashok Kumar Karuppiah
Original Assignee
Tvs Motor Company Limited
India Nippon Electricals 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 Tvs Motor Company Limited, India Nippon Electricals Ltd filed Critical Tvs Motor Company Limited
Publication of WO2022264157A1 publication Critical patent/WO2022264157A1/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
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2786—Outer rotors
    • H02K1/2787—Outer rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/2789—Outer rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2791—Surface mounted magnets; Inset magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/22—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating around the armatures, e.g. flywheel magnetos

Definitions

  • the present invention generally relates to a rotary electrical machine, and more particularly to a rotor for the rotary electrical machine.
  • a typical rotary electrical machine consists of a stator and a rotor. While the rotor has a set of permanent magnets, the stator contains stacks with slots and winding. The stacks in stator are usually made up of ferromagnetic material. Due to rotation of the rotor, there is change in strength of magnetic field in the stator. [003] It is known that in conventional rotary electric machines, the rotor holds the set of magnets radially inwards. The magnets of the rotor are magnetised in a way that the polarity of the magnets changes alternatively. This alternate arrangement of polarity causes the change in strength of magnetic field in the stator. This change in magnetic field causes a generation of a pulsating torque, also knows as torque ripple. This torque ripple leads to generation of noise. The amplitude of such noise is proportional to the rate of change in strength of magnetic field.
  • the present invention is directed towards a rotor for a rotary electric machine having a plurality of magnets.
  • Each magnet has a first region with a first polarity, a second region with the first polarity such that the first region and the second region are adjacent to each other, a third region with a second polarity such that the third region and the second region are connected by a fifth region with the second polarity.
  • the each magnet has a fourth region with the second polarity such that the fourth region is adjacent to the third region and the fourth region is connected to the first region by a sixth region with the first polarity.
  • area of the second region is lower than area of the first region and area of the fourth region is lower than area of the third region, thereby providing a skewed magnetic field strength.
  • the magnets have an arcuate cross section such that the inner curved surface area of each magnet is substantially rectangular when viewed from a centre of the rotor.
  • the first region and the third region have a rectangular shape
  • the second region and the fourth region have a trapezoidal shape
  • the fifth region and the sixth region have a right-angled triangular shape, when viewed from the centre of the rotor.
  • a base edge of the fifth region is adjacent to the third region and a hypotenuse edge of the fifth region is adjacent to the second region
  • a base edge of the sixth region is adjacent to the first region and a hypotenuse edge of the sixth region is adjacent to the fourth region.
  • area of the first region is equal to area of the third region
  • area of the second region is equal to area of the fourth region
  • area of the fifth region is equal to area of the sixth region.
  • hypotenuse edge of the fifth region and the hypotenuse edge of the sixth region join in a straight line segment, thereby providing skewed magnetic field strength.
  • area of the magnet on one side of the straight line segment has the first polarity and area of the magnet on other side of the straight line segment has the second polarity.
  • angle between the base edge and the hypotenuse edge of the fifth region is equal to angle between the base edge and the hypotenuse edge of the sixth region, and ranges between 15-25 degrees.
  • the first region has a right-angled triangular shaped seventh region with the second polarity disposed at an end of the first region, such that a hypotenuse edge of the seventh region is parallel and equal in length to the hypotenuse edge of the sixth region.
  • the third region has a right-angled triangular shaped eighth region with the first polarity disposed at an end of the third region, such that a hypotenuse edge of the eighth region is parallel and equal in length to the hypotenuse edge of the fifth region.
  • the seventh region has the second polarity
  • area of the magnet defined between the hypotenuse edge of the seventh region and the straight line segment has the first polarity
  • area of the magnet defined between the straight line segment and the hypotenuse edge of the eight region has the second polarity
  • the eight region has the first polarity, thereby providing skewed magnetic field strength.
  • the present invention relates to rotary electric machine having a stator having a plurality of stator teeth for stator windings, and a rotor having a plurality of magnets disposed facing the stator.
  • Each magnet has a first region with a first polarity, a second region with the first polarity such that the first region and the second region are adjacent to each other, a third region with a second polarity such that the third region and the second region are connected by a fifth region with the second polarity. Further, each magnet has a fourth region with the second polarity such that the fourth region is adjacent to the third region and the fourth region is connected to the first region by a sixth region with the first polarity.
  • area of the second region is lower than area of the first region and area of the fourth region is lower than area of the third region, thereby providing a skewed magnetic field strength.
  • the first region and the third region have a rectangular shape
  • the second region and the fourth region have a trapezoidal shape
  • the fifth region and the sixth region have a right-angled triangular shape, when viewed from a centre of the rotor.
  • angle between a base edge and a hypotenuse edge of the fifth region is equal to angle between a base edge and a hypotenuse edge of the sixth region, and ranges between 15-25 degrees.
  • Figure 1 illustrates an exemplary rotary electric machine, in accordance with an embodiment of the invention.
  • Figure 2 illustrates a sectional view of the rotary electric machine, in accordance with an embodiment of the invention.
  • Figure 3 illustrates an exploded view of the rotary electric machine, in accordance with an embodiment of the invention.
  • Figure 4a, 4b, 4c and 4d illustrates a front view, a side view, a perspective view and a top view of the rotor respectively, in accordance with an embodiment of the invention.
  • Figure 5 illustrates a magnet of the rotor when viewed from a centre of the rotor, in accordance with an embodiment of the invention.
  • Figure 6 illustrates the magnet of the rotor, in accordance with an embodiment of the invention.
  • Figure 7 illustrates the magnet of the rotor, in accordance with an embodiment of the invention.
  • Figure 8 illustrates the arrangement of skewed polarity on the magnets in accordance with an embodiment of the present invention.
  • the present invention relates to a rotary electrical machine.
  • the present invention relates to a rotor for a rotary electrical machine with reduced torque ripple and reduced noise.
  • Figure 1 illustrates an exemplary rotary electrical machine 10.
  • the rotary electric machine 10 comprises a rotor 20 and a stator 30 (shown in Figure 3).
  • the rotary electric machine 10 is configured for functioning as at least a generator in a vehicle for charging a battery of the vehicle.
  • the rotary electric machine 10 is coupled to an engine of the vehicle.
  • FIG. 2 illustrates a sectional view of the exemplary rotary electric machine 10 and Figure 3 illustrates an exploded view of the rotary electrical machine 10.
  • the stator 30 of the electric machine is mounted on the crankcase 40.
  • the rotor 20 of the electric machine 10 is coupled to the engine by means of a crankshaft 50. Rotation of the engine, and hence the crankshaft 50 causes the rotor 20 to rotate.
  • the stator 30 comprises a plurality of stator teeth that receive stator windings.
  • the rotor 20 comprises of a plurality of magnets 100 arranged adjoining each other so as to complete a cylinder like structure of the rotor 20.
  • the plurality of magnets 100 have an associated magnetic field and magnetic field strength.
  • the plurality of magnets 100 are arranged facing the stator 30 so that the rotation of the plurality of magnets 100 of the rotor 20 results in rotation of the associated magnetic field, generating a current in the stator winding on the stator 30.
  • the plurality of magnets 100 are arranged such that the polarity of the plurality of magnets 100 has a configuration in which a first polarity, say north pole of one magnet is arranged adjoining a second polarity, say south pole of a second magnet, the second polarity of the second magnet is arranged adjoining the first polarity of a third magnet and so on.
  • the plurality of magnets 100 have an arcuate cross section when seen in a front view. Further, each magnet 100 will accordingly have an inner curved surface area facing inwards towards the stator 30 and an outer curved surface area. It thus becomes evident that, when seen from a centre of the rotor 20, the inner curved surface area of each of the magnets 100 will have a substantially planar and rectangular shape. The substantially rectangular shape of the inner curved surface area of each magnet 100 as aforementioned, has been illustrated in Figure 5.
  • FIG. 6 further illustrates the inner curved surface area of each magnet 100.
  • each magnet has a first region 110 having the first polarity, say north pole and a second region 120 with the first polarity such that the first region 110 and the second region 120 are adjacent to each other.
  • the magnet 100 further comprises of a third region 130 having a second polarity, say south pole such that the third region 130 and the second region 120 are connected by a fifth region 150 with the second polarity.
  • the magnet 100 further has a fourth region 140 with the second polarity such that the fourth region 140 is adjacent to the third region 130 and the fourth region 140 is connected to the first region 110 by a sixth region 160 with the first polarity.
  • area of the second region 120 is lower than area of the first region 110 and area of the fourth region 140 is lower than area of the third region 130.
  • Such a configuration of polarities on the magnet 100 provides a magnet 100 wherein the first region 110, the second region 120 and the sixth region 160 combined correspond to the first polarity, and the third region 130, the fourth region 140 and the fifth region 150 combined correspond to the second polarity.
  • Such a configuration of opposing polarities on the magnet 100 thereby provides a skewed magnetic field strength, as opposed to the conventional arrangement of symmetrical and linear configuration.
  • the first region 110 and the third region 130 have a rectangular shape.
  • the second region 120 and the fourth region 140 have a trapezoidal shape and the fifth region 150 and the sixth region 160 have a right-angled triangular shape, when viewed from the centre of the rotor.
  • a base edge (OX’) of the fifth region 150 is adjacent to the third region 130.
  • a hypotenuse edge (OA’) of the fifth region 150 is adjacent to the second region 120.
  • a base edge (OX) of the sixth region 160 is adjacent to the first region 110 and a hypotenuse edge (OA) of the sixth region 160 is adjacent to the fourth region 140.
  • area of the first region 110 is equal to area of the third region 130
  • area of the second region 120 is equal to area of the fourth region 140
  • area of the fifth region 150 is equal to area of the sixth region 160. Therefore, the combined area of the first region 110, the second region 120 and the sixth region 160 corresponding to the first polarity is equal to the combined area of the third region 130, fourth region 140 and the fifth region 150 corresponding to the second polarity.
  • a straight line segment (AA’) area of the magnet 100 on one side of the straight line segment (AA’) has the first polarity and area of the magnet 100 on other side of the straight line segment (AA’) has the second polarity.
  • Such a configuration of the polarities in the magnet 100 provides for a magnet 100 wherein the line of division between the opposing polarities is skewed with respect to the edges of the magnet 100, and hence provide a skewed magnetic field.
  • angle between the base edge (OX’) and the hypotenuse edge (OA’) of the fifth region 150 is equal to angle between the base edge (OX) and the hypotenuse edge (OA) of the sixth region 160, and ranges between 15-25 degrees.
  • the maintaining of this angular range of skewing between 15 to 25 degrees leads to the electrical losses being maintained within an optimum range.
  • Figure 7 illustrates another configuration of magnet polarities in the magnet 100 of the rotor 20.
  • the first region 110 further comprises a right-angled triangular shaped seventh region 170 with the second polarity disposed at an end of the first region 110, such that a hypotenuse edge (BB’) of the seventh region 170 is parallel and equal in length to the hypotenuse edge (OA) of the sixth region 160.
  • the third region 130 further comprises a right-angled triangular shaped eighth region 180 with the first polarity disposed at an end of the third region 130, such that a hypotenuse edge (CC’) of the eighth region 180 is parallel and equal in length to the hypotenuse edge (OA’) of the fifth region 150.
  • the seventh region 170 has the second polarity
  • area of the magnet 100 defined between the hypotenuse edge (BB’) of the seventh region 170 and the straight line segment (AA’) has the first polarity
  • area of the magnet 100 defined between the straight line segment (AA’) and the hypotenuse edge (CC’) of the eight region 180 has the second polarity
  • the eight region 180 has the first polarity.
  • the present invention relates to a rotary electric machine 10 comprising a stator 30 having a plurality of teeth for stator windings, and a rotor 20 having the plurality of magnets 100 as explained hereinbefore.
  • the present invention provides for a rotor for a rotary electric machine which has reduced torque ripple and hence reduced noise, while not compromising with the voltage generation capacity of the rotary electric machine.
  • the present invention allows for the provision of a skewed arrangement of polarity in the magnets of the rotor, while not excessively increasing the electrical losses.
  • the present invention provides a rotary electric machine which can achieve reduced torque ripple and noise without an increase in the number of magnets and is therefore less cost intensive and easier to manufacture.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)

Abstract

La présente invention concerne un rotor (20) pour une machine électrique tournante (10) comprenant une pluralité d'aimants (100), chaque aimant ayant une première région (110) dotée d'une première polarité, une deuxième région (120) dotée de la première polarité de sorte que la première région et la deuxième région sont adjacentes l'une à l'autre, une troisième région (130) dotée d'une seconde polarité de sorte que la troisième région et la deuxième région sont reliées par une cinquième région (150) dotée de la seconde polarité. En outre, l'aimant comprend une quatrième région (140) dotée de la seconde polarité, de sorte que la quatrième région est adjacente à la troisième région et que la quatrième région est reliée à la première région par une sixième région (160) dotée de la première polarité, la surface de la deuxième région étant inférieure à la surface de la première région et la surface de la quatrième région étant inférieure à la surface de la troisième région, ce qui permet de fournir une intensité de champ magnétique oblique.
PCT/IN2022/050423 2021-06-14 2022-05-04 Rotor pour machine électrique tournante WO2022264157A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN202141026434 2021-06-14
IN202141026434 2021-06-14

Publications (1)

Publication Number Publication Date
WO2022264157A1 true WO2022264157A1 (fr) 2022-12-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IN2022/050423 WO2022264157A1 (fr) 2021-06-14 2022-05-04 Rotor pour machine électrique tournante

Country Status (1)

Country Link
WO (1) WO2022264157A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7061152B2 (en) * 2004-10-25 2006-06-13 Novatorque, Inc. Rotor-stator structure for electrodynamic machines

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7061152B2 (en) * 2004-10-25 2006-06-13 Novatorque, Inc. Rotor-stator structure for electrodynamic machines

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
M. AYDIN ET AL.: "Minimization of Cogging Torque in Axial-Flux Permanent-Magnet Machines: Design Concepts", IEEE TRANSACTIONS ON MAGNETICS, vol. 43, no. 9, 20 August 2007 (2007-08-20), pages 3614 - 3622, XP011190773, DOI: 10.1109/TMAG.2007.902818 *

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