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EP-4736202-A1 - ROTARY TRANSFORMER HAVING A LARGE-DIAMETER SEGMENTED RADIAL AIR GAP

EP4736202A1EP 4736202 A1EP4736202 A1EP 4736202A1EP-4736202-A1

Abstract

Disclosed is a rotary transformer that has a radial air gap and is intended to be installed around a rotatable shaft, the rotary transformer consisting of a plurality of annular stator sectors (22) and of a plurality of annular rotor sectors (24), the juxtaposition of said annular sectors forming a stator ring and a rotor ring which consist of elementary magnetic stator and rotor circuits comprising outer (30) and inner (34) magnetic cores as well as a first electrical winding (32) and a second electrical winding (36) to allow electrical energy to be transferred by electromagnetic induction between the stator and rotor rings, wherein the inner (34) and outer (30) magnetic cores, which each have a standard C-or I-shape, are axially mounted and separated by a radial air gap e_, and the outer magnetic cores and/or the inner magnetic cores have, at each of their two ends, annular flared portions (30A, 30B; 34A, 34B) that are produced by cutting into adjacent sectors a magnetic circular ring formed of an axial stack of circular metal sheets advantageously provided with notches to facilitate their assembly on the outer and inner magnetic cores.

Inventors

  • HADJIDJ, DJEMOUAI
  • BELFKIRA, Rachid

Assignees

  • Safran Electrical & Power

Dates

Publication Date
20260506
Application Date
20240617

Claims (10)

  1. [Claim 1] A rotating transformer (10) with a radial air gap intended to be installed around a rotating movable shaft (12), the rotating transformer consisting of a plurality of external stator annular sectors (22) and a plurality of internal rotor annular sectors (24), the juxtaposition over 360° of these external stator and internal rotor annular sectors forming an external stator ring and an internal rotor ring consisting of elementary stator and rotor magnetic circuits, the internal rotor annular sectors being mounted axially in the external stator annular sectors, each of the elementary stator magnetic circuits comprising an external magnetic core (30, 50) and a first electrical winding (32, 58) and each of the elementary rotor magnetic circuits comprising an internal magnetic core (34, 52) and a second electrical winding (36, 60) to allow a transfer of electrical energy by electromagnetic induction between the external stator and internal rotor rings, characterized in that that the internal (34, 52) and external (30, 50) magnetic cores, each having a C, U or I shape, are mounted axially and separated by a radial air gap (e), the external magnetic cores and/or the internal magnetic cores having at each of their two ends annular expansions (30A, 30B; 34A, 34B; 54A, 54B; 56A, 56B) which are sectors of a circular magnetic ring (46) cut out and formed from an axial stack of circular sheets.
  2. [Claim 2] A rotating transformer according to claim 1, wherein the C-shaped or I-shaped inner and outer magnetic cores (30, 34; 50, 52) are formed from a radial stack of wound sheets of a magnetic material of the amorphous or nanocrystalline type, an axial stack of flat sheets or a block of magnetic powder. made of amorphous powder and the annular expansions are formed from an axial stack of circular sheets of FeNi, FeSi or FeCo.
  3. [Claim 3] A rotating transformer according to claim 1 or claim 2, in which the annular expansions are sectors of a cut-out circular magnetic ring, formed from an axial stack of circular sheets and comprising notches (44A) in the form of crenellations.
  4. [Claim 4] A rotating transformer according to any one of claims 1 to 3, wherein the C-shaped or I-shaped external or internal magnetic cores are two identical parts of a standard oblong-shaped cut-out magnetic element (42) consisting of a radial stack of wound laminations or an axial stack of flat laminations.
  5. [Claim 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. [Claim 6] A rotating transformer according to any one of claims 1 to 5, in which the winding on the stator as well as on the rotor which can be wire or ribbon is either a concentric winding around each external or internal magnetic core or a single winding surrounding all the external or internal magnetic cores of a given annular sector.
  7. [Claim 7] A rotating transformer according to any one of claims 1 to 6, wherein the outer stator annular sectors are identical and interchangeable with each other and/or the inner rotor annular sectors are identical and interchangeable with each other.
  8. [Claim 8] A rotating transformer according to any one of claims 1 to 7, wherein the outer annular stator sectors are electrically interconnected with each other by parts flexible interconnections accessible for assembly/disassembly through circumferential access hatches (14A).
  9. [Claim 9] A rotating transformer according to any one of claims 1 to 7, in which the internal annular rotor sectors are electrically interconnected with each other by flexible interconnection parts accessible for assembly/disassembly through circumferential access hatches (14A).
  10. [Claim 10] Use of a rotating transformer according to any one of claims 1 to 9 for the electrical de-icing of the propeller blades and the nose cone of an aircraft turbomachine.

Description

Large diameter segmented radial air gap rotating transformer Technical Domain The present invention relates to the field of power transfer between a fixed reference point and a rotating reference point for the electrical (electrothermal) defrosting 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. Previous technique On electric or hybrid aircraft as on conventional aircraft, there are several surfaces to be protected 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 resistance layers covering the surfaces to be protected. To ensure the transfer of power and therefore to 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 in 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 comprising many electrified motor loads, the integration of electrical equipment is a major challenge and must meet multiple constraints linked both to accessibility for assembly/disassembly and to routing of power cables with large bending radii and servitudes such as cooling. 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 rotation shafts and in compliance with the constraints of under-wing line replaceable equipment (LRU: Line Replaceable Unit). Disclosure of the invention 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 whose topology facilitates "original assembly" by axially inserting the transformer into the engine in a single operation. Another purpose is to propose a transformer suitable for transfer in resonant or non-resonant mode with 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. 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 annular stator sectors and a plurality of internal annular rotor sectors, the juxtaposition over 360° of these external annular stator and internal annular rotor 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, characterized in that the internal and external magnetic cores are mounted axially and separated by a radial air gap, the external and internal magnetic cores each having a C or I 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 an axial stack of circular sheets. Thus, with this contactless power transfer, an improvement in the reliability, the service life and consequently the operating cost of the transformer can be obtained. In addition, better accessibility to the transformer is possible, facilitating its integration into the systems and modules of the aircraft turbomachine. Use of standard forms of magnetic circuit facilitates industrialization. Such a rotating transformer is advantageously used for the electrical de-icing of the propeller blades and the nose cone of an aircraft turbomachine. Preferab