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EP-4133582-B1 - AN ELECTRICAL MACHINE

EP4133582B1EP 4133582 B1EP4133582 B1EP 4133582B1EP-4133582-B1

Inventors

  • BOUBAKER, Nadhem

Dates

Publication Date
20260506
Application Date
20210401

Claims (15)

  1. An electrical machine (100) for use in an aircraft, comprising: a rotor (102), wherein the rotor (102) comprises a plurality of rotor poles; and a stator (108) comprising a plurality of phases, wherein each respective phase occupies at least one elementary block (116A-F), the at least one elementary block (116A-F) of each phase comprising a set of conductors (114) of the respective phase wound around a plurality of stator teeth (118) and received by a plurality of slots (112) of the respective elementary block (116A-F) in a concentrated winding configuration; characterized in that the stator (108) further comprises at least one sensor (122A-B) located between two elementary blocks (116A-F), the at least one sensor (122A-B) being configured to measure at least one parameter of the rotor (102).
  2. An electrical machine according to claim 1, wherein at least one of the following applies: (i) the at least one sensor (122A-B) is configured to measure an angular position of the rotor (102); and (ii) the at least one sensor (122A-B) is configured to measure a temperature of the rotor (102).
  3. An electrical machine according to any of preceding claim, wherein the at least one sensor (122A-B) comprises at least one sensor coil (124) received by a pair of adjacent slots (126A-B).
  4. An electrical machine according to claim 3, further comprising at least one power electronics module (130A-B) for treating the electrical output of the concentrated windings, wherein the at least one power electronics module (130A-B) is electrically connected to conductors (114) of at least one phase of the plurality of phases, and wherein the at least one sensor coil (122A-B) is electrically connected to a power electronics module (130A-B) of the electrical machine (100).
  5. An electrical machine according to claim 3, wherein the at least one sensor coil (124) is arranged to measure an angular position of the rotor (102) based on the voltage induced therein.
  6. An electrical machine according to any of claims 3 to 5, wherein the at least one sensor coil (124) is arranged to measure a temperature of the rotor (102) based on the voltage induced therein.
  7. An electrical machine according to any of claims 3 to 6, wherein a first mechanical shift angle between the sensor coil (124) and an adjacent elementary block (116A-F) is greater than the rotor pole pitch, the rotor pole pitch being an angle between adjacent poles of the rotor (102), and optionally, wherein a second mechanical shift angle between the respective concentrated windings of each pair of adjacent elementary blocks (116A-F) is less than the rotor pole pitch, wherein the second mechanical shift angle is optionally about two thirds of the rotor pole pitch.
  8. An electrical machine according to any preceding claim, wherein the stator (108) comprises two sensors (122A-B).
  9. An electrical machine according to claim 8, wherein each of the two sensors (122A-B) comprises a sensor coil (124) received by a pair of adjacent slots (126A-B).
  10. An electrical machine according to claims 8 or 9, wherein the two sensors (122A-B) comprise a first sensor (122A) at a first position on the stator (108) and a second sensor (122B) at a second position on the stator (108), wherein optionally the first and second positions are diametrically opposed or the first position is adjacent to the second position.
  11. An electrical machine according to claim 8, wherein the two sensors (122A-B) comprise a first sensor coil (124) and a second sensor coil (124), the first and second sensor coils (124) being received by a mutual pair of adjacent slots (126A-B).
  12. An electrical machine according to any proceeding claim, wherein the rotor (102) comprises a plurality of permanent magnets (106).
  13. An electrical machine according to any proceeding claim, wherein each phase comprises two elementary blocks (116A-F) being connected by a single end conductor (114).
  14. An electrical machine according to any proceeding claim, wherein the stator (108) comprises three phases.
  15. An aircraft propulsion system comprising an electrical machine (100) according to any of the preceding claims.

Description

The present invention relates to an electrical machine for use in an aircraft. In particular, the present invention relates to an electrical machine with an integrated sensor for detecting parameters of the rotor, such as position and temperature. Background to the Invention Electric aircraft propulsion systems typically comprise a fan (propeller), which is connected to an electrical machine. The electrical machine is typically formed of an assembly of magnetic circuit components, comprising a rotor and a stator. As is well known, rotation of the rotor relative to the stator causes interaction of the magnetic field generated by the rotor with windings provided on the stator, generating an induced electromotive force (EMF) and/or electrical current. In a permanent magnet generator, the rotor's magnetic field is produced by permanent magnets, which induces an AC voltage in the stator windings as the stator windings pass through the moving magnetic field of the permanent magnet. In order to control the machine so as to synchronise the armature AC excitation with the rotational speed (i.e. the back EMF), and thus subsequently obtain the torque, the rotor position must be known. Typically, the rotor position is measured using a resolver or Hall Effect sensor that is integrated in the rotor and rotates with it. However, a shaft mounted sensor such as those typically used can be very costly, particularly if high accuracy is required, can be unreliable and have low fault tolerance, are usually very bulky and can add to the overall weight of the machine since a bigger shaft is required to accommodate the sensor. To overcome the problems of a sensor integrated with the rotor, "sensorless control laws", also known as observers and estimators, are implemented. This technique monitors the rotor position by only measuring the electrical waveforms (voltages and currents) of the stator windings via the power electronics. However, this method is not particularly robust at low speeds and/or low loads since there is very little back EMF and/or currents being generated, and is not always found to be accurate. US 2018/026502 relates to a rotating electric machine includes: a stator having an armature core having slots formed between magnetic pole teeth, and a plurality of coils each of which is wound so as to straddle a plurality of the magnetic pole teeth; and a rotor including a plurality of permanent magnets disposed at certain intervals on an outer peripheral surface of the magnetic yoke, and the coils include an armature coil for driving the rotating electric machine and a non-armature coil for magnetizing or demagnetizing the permanent magnets of the rotor. DE 10 2018 211089 relates to a sensor device for detecting a rotor position of a rotor of an electric machine for a motor vehicle, comprising a plurality of measuring coils. The measuring coils are arranged on a holding frame of the sensor device, wherein the sensor device has an engagement device arranged on the holding frame with at least one engagement strut for engaging in a stator slot of a stator of the electric machine. US 2014/091666 relates an electrical machine comprising a plurality of stator segments, wherein each segment has a plurality of electrical phase windings embedded in stator slots in a phase sequence, wherein the phase of the first slot of a segment is different from the phase of the first slot of an adjacent segment. Therefore, there is a need to improve the way in which the rotor position is monitored in an electrical machine. Summary of the Invention A first aspect of the invention provides an electrical machine for use in an aircraft, comprising a rotor, wherein the rotor comprises a plurality of rotor poles, and a stator comprising a plurality of phases, wherein each respective phase occupies at least one elementary block, the at least one elementary block of each phase comprising a set of conductors of the respective phase wound around a plurality of stator teeth and received by a plurality of slots of the respective elementary block in a concentrated winding configuration, wherein the stator further comprises at least one sensor located between two elementary blocks, the at least one sensor being configured to measure at least one parameter of the rotor. As such, the concentrated windings for each phase of the stator are grouped together in at least one block, with at least one sensor for measuring parameters of the rotor being integrated in the stator between two of these blocks. Arranging the sensor in this way removes the need to provide a sensor on the rotating armature of the rotor itself, and contributes to reducing the overall weight and cost of the electrical machine. The at least one sensor may be configured to measure an angular position of the rotor. The at least one sensor may also be configured to measure a temperature of the rotor. The at least one sensor may comprise at least one sensor coil wound around a pair of adjacent sl