Standardized segmented large-diameter rotary transformer
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SAFRAN ELECTRICAL & POWER
- Filing Date
- 2024-06-19
- Publication Date
- 2026-05-06
AI Technical Summary
Existing solutions for power transfer between fixed and rotating parts of aircraft turbomachines, such as slip rings, have limited lifespan due to wear and are challenging to integrate in severe environments, leading to high operating costs and accessibility issues.
A large diameter, segmented rotating transformer with external annular stator and internal annular rotor sectors using electromagnetic induction for contactless power transfer, facilitating maintenance and industrialization while reducing material waste.
The solution enhances reliability, lifespan, and operating cost by enabling efficient contactless power transfer, improving accessibility, and simplifying maintenance, thus facilitating integration into aircraft systems.
Smart Images
Figure FR2024050806_02012025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Title of the invention: Large diameter standardized segmented rotating transformer
[0003] Technical Field
[0004] The present invention relates to the field of power transfer between a fixed reference point and a rotating reference point for the electrical (electrothermal) de-icing of the propeller blades of an aircraft turbomachine and relates to a single-phase rotating transformer used in a harsh environment for the contactless transmission of electrical energy by electromagnetic induction between first and second electrical windings of this transformer.
[0005] Prior art
[0006] On electric or hybrid aircraft, as on conventional aircraft, there are several surfaces to protect against frost on the fixed and rotating parts of the turbomachine. The protection envisaged for the rotating parts is generally exclusively electrothermal based on electric heating mats formed of layers of resistance covering the surfaces to be protected.
[0007] To ensure the transfer of power and therefore convey the electrical energy from the fixed part to the rotating part where the electric heating mats are installed, it is known to use a device called a "slip ring" whose principle consists of rubbing several fixed conductive rings secured to the fixed part on circular conductive tracks secured to the rotating part, in order to create an electrical connection between the fixed part and the rotating part of the turbomachine. However, the major drawback of this solution lies in its very limited service life due to the wear of the parts in continuous friction, which therefore generates unacceptable operating costs on a single-aisle commercial aircraft of the A320 or B737 type where the rotating part endures multiple rotations.Furthermore, it is known that due to the harsh environment (thermal, electromagnetic and vibration) existing in hybrid aircraft with numerous electrified engine loads, the integration of electrical equipment is a major challenge and must meet multiple constraints linked both to accessibility for assembly / disassembly and to the routing of power cables with large bending radii and services such as cooling.
[0008] There is therefore a current need for a reliable and long-life solution for transferring power from a fixed reference to a rotating reference applicable to large diameter rotating shafts and respecting the constraints of under-wing line replaceable equipment (LRU: Line Replaceable Unit).
[0009] Statement of the invention
[0010] The main purpose of the present invention is therefore a large diameter rotating transformer, segmented into quarters, whose maintenance is facilitated and does not interfere with the other systems and modules of the aircraft turbomachine, despite its installation in a confined, constrained and difficult-to-access area. Another purpose is to propose a transformer allowing simplified but robust control. Yet another purpose is to allow industrialization of this rotating transformer at a lower cost, while limiting material waste during manufacturing.
[0011] These aims are achieved by a rotating transformer intended to be installed around a rotating movable shaft, the rotating transformer being made up of a plurality of external stator annular sectors and a plurality of internal rotor annular sectors, the juxtaposition over 360° of these external stator and internal rotor annular sectors forming an external stator ring and an internal rotor ring made up of a set of elementary stator and rotor magnetic circuits, each of the elementary stator magnetic circuits comprising an external magnetic core and a first electrical winding and each of the elementary rotor magnetic circuits comprising an internal magnetic core and a second electrical winding to allow a transfer of electrical energy by electromagnetic induction between the external stator and internal rotor rings,the internal and external magnetic cores being mounted concentrically and separated by two air gaps present on either side of the internal magnetic core, the external magnetic cores each have a C-shaped claw and the internal magnetic cores each have an I-shaped bar shape and in that the external magnetic cores and / or the internal magnetic cores have at each of the air gaps annular expansions produced by cutting into adjacent sectors a circular magnetic ring formed from a radial stack of circular sheets.,
[0012] Thus, with this contactless power transfer, an improvement in the reliability, lifespan and operating cost of the transformer is obtained. In addition, better accessibility to the transformer is possible, facilitating its integration into the systems and modules of the aircraft turbomachine. Such a rotating transformer is advantageously used for the electrical de-icing of the propeller blades of an aircraft turbomachine.
[0013] Preferably, the internal and external magnetic cores are formed from a radial stack of wound sheets of a magnetic material of the amorphous or nanocrystalline type or from a block of magnetic powder made of amorphous powder.
[0014] According to the embodiment envisaged, to allow the insertion of the internal magnetic core into the external magnetic core and the creation of the air gaps on either side of the internal magnetic core, the C-shaped external magnetic core is produced by cutting to the size of the internal magnetic core, the annular expansions and the air gaps, i.e. from a standard oblong-shaped magnetic element consisting of a radial stack of wound sheets.
[0015] Preferably, the number of annular sectors in the stator is or is not identical to the number of annular sectors in the rotor and the number of external magnetic cores per external annular sector of the stator is or is not identical to the number of internal magnetic cores per internal annular sector of the rotor. Advantageously, the winding in the stator which can be wire or ribbon is either a concentric winding around each external magnetic core or a single winding surrounding all the external magnetic cores of a given annular sector and the winding in the rotor which can be wire or ribbon is either a concentric winding around each internal magnetic core or a single winding surrounding all the internal magnetic cores of a given annular sector.
[0016] Preferably, the annular expansions have notches to facilitate their assembly on the internal or external magnetic cores.
[0017] Advantageously, the external annular stator sectors are identical and interchangeable with each other and / or the internal annular rotor sectors are identical and interchangeable with each other.
[0018] Preferably, the external annular stator sectors are electrically interconnected with each other by flexible interconnection parts accessible for assembly / disassembly through circumferential access hatches and / or the internal annular rotor sectors are electrically interconnected with each other by flexible interconnection parts accessible for assembly / disassembly through circumferential access hatches. It is important to note that these electrical interconnection parts for both the stator and the rotor must be flexible (braid type or equivalent) and not mechanically structural to limit (or even avoid) the transmission of mechanical forces between adjacent sectors.
[0019] Brief description of the drawings
[0020] Other characteristics and advantages of the present invention will emerge more clearly from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not in any limiting nature and in which:
[0021] [Fig. 1] Figure 1 illustrates a part of an aircraft turbomachine incorporating a rotating transformer according to the invention, [Fig. 2] Figure 2 shows a section of the rotating transformer of Figure 1, [Fig. 3A-3B] Figures 3A and 3B show an example of an embodiment of an external magnetic stator core making up the rotating transformer section of Figure 2,
[0022] [Fig. 4A] Figure 4A shows a segment of the stator quarter making up the rotating transformer quarter of Figure 2,
[0023] [Fig. 4B] Figure 4B shows a segment of the rotor quarter making up the rotating transformer quarter of Figure 2,
[0024] [Fig. 5] Figure 5 illustrates a first example of a rotating transformer district segment according to the invention,
[0025] [Fig. 6] Figure 6 illustrates a second example of a rotating transformer district segment according to the invention,
[0026] [Fig. 7] Figure 7 shows a third example of a rotating transformer district segment according to the invention, and
[0027] [Fig. 8] Figure 8 shows a fourth example of a rotating transformer district segment according to the invention.
[0028] Description of the embodiments
[0029] The principle of the invention implemented is based on a segmentation of the rotating transformer, at the stator (called primary) as at the rotor (called secondary), into several annular sectors or quarters each having a mass and a replacement time compatible with a ground maintenance operation limiting the downtime of the aircraft, so that the maintenance and replacement interventions (assembly / disassembly) are facilitated and can be carried out by conventional tools through dedicated access hatches, without having to disassemble or interfere with the other parts of the aircraft turbomachine. To do this, the annular stator sectors are identical and interchangeable with each other and the annular rotor sectors are identical and interchangeable with each other. The power transfer between the stator and the rotor is done by electromagnetic induction and without contact.The stator is powered by dedicated electronics (resonant or non-resonant single-phase inverter) operating preferably at high frequencies (several tens of kilohertz), without this being limiting.
[0030] As shown in Figure 1 which is a part of an aircraft turbomachine, the rotating transformer 10 according to the invention is mounted between a rotating transmission shaft 12 forming a rotating part of the turbomachine and a casing 14 forming a fixed part of the turbomachine, provided with circumferential access hatches 14A through which each of the annular quarters or sectors of the rotating transformer 10 can be installed or easily removed for repair or maintenance and then reinstalled once these replacement operations have been carried out.
[0031] Figure 2 illustrates more precisely an example of an annular sector or quarter 20 of the rotating transformer 10 (which in the illustrated example comprises a single path but two axially offset redundant paths would also be possible) consisting of a fixed stator quarter 22 secured to the casing and a rotating rotor quarter 24 secured to the transmission shaft, the rotor quarter being mounted concentrically (inserted) in the stator quarter to form the transformer quarter while maintaining axial mechanical play on either side of the rotor quarter. The rotating transformer formed by the juxtaposition over 360° of several quarters 20 has a large diameter, of the order of a meter or more, which allows the rotor to receive a transmission shaft also of large diameter, such as a propeller shaft.
[0032] According to the invention, the juxtaposition over 360° of these different annular sectors to the stator and to the rotor form an external stator ring and an internal rotor ring consisting of a plurality of single-phase elementary stator and rotor magnetic circuits respectively comprising a stator magnetic core 30 and a first electrical winding (primary 32) and a rotor magnetic core 34 and a second electrical winding (secondary 36), the stator and rotor magnetic cores being separated by two air gaps e1 and e2 present on either side of the rotor magnetic core (see figure 5) and the sectors being able to be electrically interconnected in series or in parallel for the transmission of electrical energy by electromagnetic induction between the first and second electrical windings of these elementary stator and rotor magnetic circuits.As previously indicated, both in the stator and in the rotor, the annular sectors are identical and interchangeable with each other. However, the number of these elementary magnetic circuits per annular sector is not necessarily identical in the stator and in the rotor (for example four in the stator and six in the rotor as illustrated), the choice of the number of magnetic circuits in the stator and in the rotor being guided by design considerations and optimization of transfer performance. As for the numbers of magnetic circuits in the stator and rotor which can be different, the number of sectors in the stator can also be different from the number of sectors in the rotor.
[0033] An annular sector on the stator or rotor is designed as a LRU (Line Replaceable Unit) that can be dismantled and replaced under the wing through dedicated circumferential access hatches 14A. They are electrically interconnected by flexible interconnection parts (not referenced) that are also accessible for assembly / disassembly through the circumferential access hatches 14A.
[0034] The type of material used for the magnetic core or the expansions may be different for the stator and the rotor (for example, winding or stacking of FeNi type sheets, or another material such as FeSi or FeCo, for the stator and powder block for the rotor). But a magnetic core made of wound amorphous or nanocrystalline type sheet or in the form of a powder block of any other suitable magnetic material (for example, Amorphous powder) is preferably considered. The use of Amorphous or Nanocrystalline type materials makes it possible to reduce the size and mass of the transformer as well as its losses.
[0035] Different topologies are possible for each elementary magnetic circuit in the stator and rotor allowing the production of the rotating transformer according to the invention. These topologies all have in common the fact that the stator magnetic cores (or external stator 30) and / or the rotor magnetic cores (or internal rotor 34) have at each of the air gaps expansions 30A, 30B; 34A, 34B produced economically with standard magnetic shapes without wasting materials during cutting. The expansions are intended to avoid a discontinuity of the magnetic field lines during rotation, thereby improving the transfer efficiency and simplifying the management of the resonant mode by simplified control independent of the rotation (limited variations of the transformer parameters according to the angular position).
[0036] Thus, and as shown in Figures 3A and 3B, the magnetic core of the stator 30 is obtained from an assembly of two elements: a standard magnetic element 40 in the shape of a C (better known by the acronym C-core) resulting from a cutting of a radial stack of laminations wound 42 around a common axis, and an annular expansion 44 resulting from the cutting of a magnetic circular ring 46 made of a radial stack of circular laminations predefined to the correct diameter. The circular ring is cut into a determined number of annular sectors intended to constitute the complete transformer.
[0037] Similarly, the magnetic core of the rotor 34 is obtained from an assembly of two elements: a standard I-shaped magnetic element 48 (a simple bar visible in Figure 8) and the same annular expansion 44 resulting from the cutting of the same circular ring 46 made from a radial stack of circular sheets predefined to the correct diameter on the same principle as the stator.
[0038] To facilitate the assembly of the expansions on the C-cores and I-shapes on both the stator and the rotor, these can be provided with notches 44a, 44b, 44c, 44d. In the case where cutting out notches is not feasible (case of a material such as Amorphous), the use of FeNi for the expansions can then be considered.
[0039] As shown in Figures 4A and 4B, the stator winding is a concentric winding 50 around each C-core. Similarly, the rotor winding is a concentric winding 52 around each I-element. The windings can be wire or ribbon depending on the different integration and performance constraints to be met.
[0040] The stator coils within an annular sector are interconnected in series. The annular sectors are also interconnected in series to form the primary winding of the complete transformer. The same principle of interconnection between sectors and within each sector is implemented for the rotor.
[0041] In Figure 4A, the magnetic cores of the stator 40 comprise annular expansions 44 at each of their two ends but a configuration without expansions is also possible, as will be shown further with reference to Figure 7. Similarly, in Figure 4B, the magnetic cores of the rotor 48 comprise annular expansions 44 at each of their two ends but a configuration without expansions is also possible, as will be shown further with reference to Figure 6.
[0042] All parts are assembled and held together by suitable mechanical parts (not shown).
[0043] Figure 5 illustrates a first example of a segment (a portion comprising two stator magnetic cores) of a transformer quarter in which the stator magnetic cores 40 and the rotor magnetic cores 48 each comprise annular expansions 44, the air gaps e1 and e2 being located between these annular expansions at the stator and rotor. The stator winding is formed of the concentric coils 50 around each C-core type claw element and the rotor winding is formed of the concentric coils 52 around each I-shaped element.
[0044] Figure 6 illustrates a second example of a segment (a part comprising two stator magnetic cores) of a transformer quarter in which only the stator magnetic cores 40 each comprise annular expansions 44 (provided with notches in this example), the air gaps e1 and e2 then being located between these annular expansions of the stator and the rotor magnetic cores 48. The stator windings are concentric windings
[0045] 50 around each C-core element and the rotor windings are concentric windings 52 around each I-core element.
[0046] Figure 7 illustrates a third example of a segment (a part comprising two stator magnetic cores) of a transformer district in which only the rotor magnetic cores 48 each comprise annular expansions 44, the air gaps e1 and e2 then being located between these annular expansions of the rotor and the stator magnetic cores 40. The stator windings are concentric windings 50 around each C-core element and the rotor windings are concentric windings 52 around each I-element.
[0047] Figure 8 illustrates a fourth example of a segment (a portion comprising two stator magnetic cores) of a transformer quarter in which the stator magnetic cores 40 and the rotor magnetic cores 48 each comprise annular expansions 44, the air gaps e1 and e2 being located between these annular expansions at the stator and the rotor. However, unlike the previous examples, the stator windings are formed of a single winding 54 surrounding all the C-core elements of a given annular sector of the transformer and the rotor windings are formed of a single winding 56 surrounding all the I-elements of the same given annular sector of the transformer.
[0048] 51 as an application, reference has been made to the de-icing of propeller blades of an aircraft turbomachine, among other possible applications, particularly in the aeronautical industry, which can benefit from the use of rotating transformers, we can cite the feedback of information from torque sensors for the variable pitch of blades in airplanes and the pitch setting of propeller in helicopters, for example. For such applications, the elimination of the conventional rubbing brush collector and its replacement by a rotating transformer is advantageous because it makes the equipment more reliable by eliminating the risk of breakdown created by the frequent wear of the brushes. Thus, the invention has in particular the following advantages:
[0049] . an improvement in the reliability and lifespan of the defrosting system through a contactless transfer solution,
[0050] . reduced system operating costs through improved reliability and accessibility (improved equipment replacement time),
[0051] . easy integration of the defrosting system on the turbomachine.
Claims
Claims
1. A rotating transformer (10) intended to be installed around a rotating movable shaft (12), the rotating transformer consisting of a plurality of external annular stator sectors (22) and a plurality of internal annular rotor sectors (24), the 360° juxtaposition of these external annular stator and internal rotor sectors forming an external stator ring and an internal rotor ring consisting of elementary stator and rotor magnetic circuits, the internal annular rotor sectors being inserted axially into the external annular stator sectors, each of the elementary stator magnetic circuits comprising an external magnetic core (30; 40) and a first electrical winding (32; 50, 54) and each of the elementary rotor magnetic circuits comprising an internal magnetic core (34; 48) and a second electrical winding (36;52, 56) to allow a transfer of electrical energy by electromagnetic induction between the outer stator and inner rotor rings, the inner and outer magnetic cores being mounted concentrically and separated by two axial air gaps e1 and e2 present on either side of the inner magnetic core (48), characterized in that the outer magnetic cores (40) each have a C-shaped claw and the inner magnetic cores (48) each have an I-shaped bar and in that the outer magnetic cores (40) and / or the inner magnetic cores (48) have at each of the air gaps annular expansions (44) produced by cutting into adjacent sectors a circular magnetic ring (46) formed from a radial stack of circular sheets.;
2. A rotating transformer according to claim 1, wherein the inner and outer magnetic cores (30, 40; 34, 48) are formed from a radial stack of wound sheets of magnetic material of amorphous or nanocrystalline type or a block of magnetic powder made of amorphous powder.
3. A rotating transformer according to claim 1 or claim 2, wherein to enable the insertion of the internal magnetic core into the external magnetic core and the creation of the air gaps on either side of the internal magnetic core, the C-shaped external magnetic core (40) is produced by cutting to the size of the internal magnetic core, the annular expansions and the air gaps, a standard oblong-shaped magnetic element (42) consisting of a radial stack of wound sheets.
4. A rotating transformer according to any one of claims 1 to 3, wherein the number of annular sectors on the stator is or is not identical to the number of annular sectors on the rotor.
5. A rotating transformer according to any one of claims 1 to 4, wherein the number of external magnetic cores per external stator annular sector is or is not the same as the number of internal magnetic cores per internal rotor annular sector.
6. A rotating transformer according to any one of claims 1 to 5, wherein the annular expansions comprise notches (44a, 44b, 44c, 44d) to facilitate their assembly on the internal or external magnetic cores.
7. A rotating transformer according to any one of claims 1 to 6, wherein the stator winding which may be wire or ribbon is either a concentric winding around each external magnetic core or a single winding (54) surrounding all the external magnetic cores of a given annular sector and the rotor winding which may be wire or ribbon is either a concentric winding around each internal magnetic core or a single winding (56) surrounding all the internal magnetic cores of a given annular sector.
8. A rotating transformer according to any one of claims 1 to 7, wherein the outer annular stator sectors are identical and interchangeable with each other and / or the inner annular rotor sectors are identical and interchangeable with each other.
9. A rotating transformer according to any one of claims 1 to 8, wherein the outer annular stator sectors are electrically interconnected with each other by flexible interconnecting parts accessible for assembly / disassembly through circumferential access hatches (14A) and / or the inner annular rotor sectors are electrically interconnected with each other by flexible interconnecting parts accessible for assembly / disassembly through circumferential access hatches (14A).
10. Use of a rotating transformer according to any one of claims 1 to 9 for the electrical de-icing of the propeller blades of an aircraft turbomachine.