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KR-102963521-B1 - MAGNETS IN ELECTRICAL MACHINES

KR102963521B1KR 102963521 B1KR102963521 B1KR 102963521B1KR-102963521-B1

Abstract

The present invention relates to a rotor for an electric machine comprising a first type of permanent magnet and a second type of permanent magnet, wherein the first type of permanent magnet and the second type of permanent magnet have the same magnetic strength, the first type of permanent magnet has a first temperature class, and the second type of permanent magnet has a second temperature class different from the first temperature class. The present disclosure relates to a generator, in particular, a wind turbine comprising such a generator, and a method for selecting or providing a magnet for a permanent magnet rotor.

Inventors

  • 우레스티 훌리오 세자르
  • 아파네조프 미카일
  • 갈레스 라벤토스 네우스
  • 할 로스

Assignees

  • 제너럴 일렉트릭 레노바블레스 에스빠냐 에스.엘.유.

Dates

Publication Date
20260511
Application Date
20211029
Priority Date
20201106

Claims (15)

  1. As a rotor for an electric machine comprising a first type permanent magnet and a second type permanent magnet, Type 1 permanent magnets and Type 2 permanent magnets have the same magnetic strength, and A first type of permanent magnet has a first temperature class, and a second type of permanent magnet has a second temperature class different from the first temperature class, and The above rotor is, Radial rotor edge; and A plurality of permanent magnet modules, each permanent magnet module comprising a base attached to the radial rotor edge. Includes, A rotor comprising a permanent magnet module including a first magnet zone in which at least one of the first type of permanent magnet is disposed on the base and a second magnet zone in which at least one of the second type of permanent magnet is disposed on the base.
  2. In Article 1, A rotor in which the first type of permanent magnet and the second type of permanent magnet are formed of rare earth materials.
  3. In Article 1 or Article 2, The above radial rotor edge extends axially from the first end to the second end, and A rotor in which the first magnet region is closer to the first end than the second magnet region.
  4. In Paragraph 3, A rotor configured such that the first end is closer to the cooling air supply than the second end, in such a manner that the rotor is arranged in an electric machine.
  5. In Article 1 or Article 2, The permanent magnet module additionally includes a third magnet zone of a third type of permanent magnet, and A rotor having a third type of permanent magnet having the same magnetic strength and a third temperature grade different from the first temperature grade and the second temperature grade.
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  7. In Article 1 or Article 2, The above permanent magnet module includes one or more inclined magnets arranged at an angle with respect to the radial direction and one or more tangential magnets arranged perpendicular to the radial direction, and A rotor in which the inclined magnet is the first type of magnet and the tangential magnet is the second type of magnet.
  8. A rotor according to Article 1 or Article 2 An electric machine including
  9. A wind turbine comprising a tower, a nacelle rotatably mounted on the tower, a wind turbine rotor comprising a plurality of blades, and an electric machine according to claim 8.
  10. A step of determining the magnetic remanence of a permanent magnet in a permanent magnet rotor of an electric machine; Step of determining the temperature distribution of a permanent magnet rotor in operation; A step of determining a first zone of a permanent magnet rotor having a lower average temperature and a step of determining a second zone of a permanent magnet rotor having a higher average temperature; A step of selecting a first type of permanent magnet for a first zone and selecting a second type of permanent magnet for a second zone that is different from the first type; and A step of providing a permanent magnet module comprising a base attached to a radial rotor edge of a permanent magnet rotor, a first magnet zone in which at least one of the first type of permanent magnet is disposed on the base, and a second magnet zone in which at least one of the second type of permanent magnet is disposed on the base. A method including
  11. In Article 10, A method in which the first type of magnet has a lower temperature rating than the second type of magnet.
  12. In Article 10 or Article 11, A method in which the step of determining the temperature distribution of a permanent magnet rotor in operation includes the step of simulating the operation of an electric machine.
  13. In Article 10 or Article 11, A method in which the first type of magnet and the second type of magnet are provided by additive manufacturing.
  14. delete
  15. delete

Description

Magnets in Electric Machines The present disclosure relates to electric machines, and more specifically to electric machines comprising permanent magnets. The present disclosure also relates to wind turbines comprising such electric machines, in particular to wind turbines comprising a permanent magnet generator having a cooling device. Electric machines, such as motors and generators, generally include a rotor structure and a stator structure. Large generators may be, for example, permanent magnet excited generators (PMGs). Such generators may be used, for example, in wind turbines. Wind turbines generally include a rotor hub and a rotor having multiple blades. The rotor is set to rotate under the influence of wind on the blades. The rotation of the rotor shaft directly drives the generator rotor ("direct drive") or drives it through the use of a gearbox. Such direct drive wind turbine generators may have, for example, a diameter of 6 to 10 meters (236 to 328 inches) and a length of, for example, 2 to 3 meters (79 to 118 inches), and may rotate at a low speed in the range of, for example, 2 to 20 rpm (revolutions per minute). Alternatively, a permanent magnet generator may also be coupled to a gearbox that increases the generator's rotational speed, for example, to 50 to 500 rpm or even higher. An electric machine includes a rotor that rotates relative to a stator. The rotor may be an internal structure, or the stator may be an external structure. Thus, in this case, the stator surrounds the rotor. Alternatively, the configuration may be the opposite, namely, the rotor surrounds the stator. In the case of permanent magnet excitation generators (PMGs), permanent magnets (PM) are typically housed in the rotor (permanent magnets can also be placed in the stator structure as an alternative), while winding elements (e.g., coils) are usually housed in the stator (winding elements can also be placed in the rotor structure as an alternative). Permanent magnet generators are generally considered reliable and require less maintenance than other generator types. This is a key reason why permanent magnet generators are adopted in offshore wind turbines, particularly direct-drive offshore wind turbines. Multiple permanent magnets may be provided in a permanent magnet module, and the module may be attached to the rotor as a single item. The permanent magnet module may be defined as a unit comprising multiple permanent magnets, so that multiple permanent magnets can be mounted and detached together. Such a module may have a module base having a shape suitable for accommodating or transporting multiple permanent magnets that may be fixed to the base. The base may be configured to be fixed to the rotor rim in such a way that multiple magnets are fixed together to the rotor rim through the module base. Using a permanent magnet module may facilitate the manufacturing of the rotor. Since active elements (magnets or coils) heat up during use, cooling is generally important in electric machinery. If the temperature becomes too high, these elements may fail and operating efficiency may decrease. Various configurations for electric machines are known, for example, radial machines and axial machines. In axial machines, the rotor and the stator face each other axially. An air gap is positioned axially between the rotor and the stator. In radial machines, a substantially annular air gap may be formed between the rotor and the stator. The rotor and the stator are positioned so that one surrounds the other radially. Due to the movement of the rotor, the air within the air gap moves around. This allows the air to provide a cooling effect, particularly in the case of high-speed rotation. It is known that active air cooling or air conditioning systems provide a low-temperature airflow through an internal stator structure. The cooling airflow is then distributed along the circumference of the stator. The airflow then axially crosses the air gap from one side to the other, thereby cooling the active elements of the rotor and stator. The hot air is then collected from the axial opposite side. The hot air can then be exhausted in a heat exchanger or cooled and reused. This type of cooling, where the cooling air axially crosses the radial air gap, is generally referred to as axial cooling. Radial cooling is also known, in which cooling air is blown radially at various points along the axial length of a typical rotor within a radial air gap. While axial cooling is generally preferred in axially short electric machines, radial cooling is often preferred in axially long electric machines. Because the cooling air traverses the air gap axially from one side to the other, the air is heated as it passes through the air gap. Consequently, the cooling air is colder on one side than on the opposite side, and thus provides more effective cooling on one side than on the other. As a result, the cooling of the active element is not uniform; that is, the ma