Turbine generator for hybrid electric aircraft propulsion

Abstract

The present invention relates to an aircraft turbine generator for hybrid electric propulsion, comprising a heat engine (12) and a generator (10), the generator being mechanically connected to the heat engine and comprising a rotor and a stator, the rotor extending in an axial direction and comprising a common magnetized rotor yoke (100) comprising a plurality of permanent magnets (102) defining at least three axially distributed movable annular rings (102A, 102B, 102C), the stator comprising a magnetic stator yoke (200) comprising a plurality of electrical windings (202) defining axially and / or circumferentially distributed fixed sectors (202A, 202B, 202C), wherein one of the windings axially covers at least two fixed sectors of at least two movable annular rings arranged at an angle so as not to overlap with each other, and thus outputting at least two separate, independent voltage levels.

Description

Technical Field

[0001] This invention relates to the field of hybrid aviation propulsion, and more specifically to a turbine generator capable of delivering multiple output voltages at different power levels. Background Technology

[0002] In a traditional turbine generator, the generator connected to the heat engine produces total power at a given voltage level. The energy is then converted by power electronics to different voltage levels required by the electrical load. The disadvantage of this is high quality, especially when the voltage conversion ratio is very high, which requires different conversion stages.

[0003] These power electronic devices are also an additional link in the efficiency chain, leading to reduced reliability, additional power requirements to compensate for this reduction in efficiency, and additional cooling requirements associated with the thermal properties of the associated losses.

[0004] Furthermore, the gas generator of an aircraft turbine is typically equipped with an electric starter that can operate in generator mode (at a conventional voltage level of 28 Vdc) when the turbine is started. Its efficiency is typically low (about 70-75%) and it has a relatively high mass (approximately 1.5 kg per kilowatt).

[0005] However, the increasing maturity of hybrid aerospace propulsion architectures allows for the use of electrical loads that may employ different power and voltage levels.

[0006] Application FR2566975 discloses a generator with multiple outputs, comprising a common permanent magnet rotor and a stator equipped with multiple windings, which in particular allow the formation of three distinct but non-independent three-phase systems.

[0007] Today, we also need to address the technical challenges brought about by these new architectures, which include rationalizing power generation and conversion devices, reducing their size, and improving their efficiency and reliability. Summary of the Invention

[0008] In response to this demand, an aircraft turbine generator for hybrid electric propulsion is proposed, comprising:

[0009] - Heat engine

[0010] - A generator, mechanically connected to a heat engine, and comprising a rotor and a stator.

[0011] The rotor extends axially and includes a common magnetized rotor yoke comprising a plurality of permanent magnets defining at least three axially distributed movable annular rings.

[0012] The stator includes a magnetic stator yoke, which comprises a plurality of electrical windings defining fixed sectors distributed axially and / or circumferentially.

[0013] The feature is that at least two fixed sectors (including a fixed sector axially covering at least two movable annular rings) are arranged at an angle so that they do not overlap with each other, and thus deliver at least two different and independent voltage levels.

[0014] Therefore, while increasing reliability, availability, and power output, and reducing size, a readily available multiphase AC grid can be placed under the control of electrical loads.

[0015] Preferably, at least one fixed sector has an axial dimension different from that of the other fixed sector.

[0016] Advantageously, fixed sectors with different axial dimensions correspond to rotor movable annular rings with defined axial dimensions.

[0017] Preferably, a portion of one fixed sector and a portion of another fixed sector are associated with a rotor movable annular ring.

[0018] Advantageously, fixed sectors are separated by simple air gaps or by barriers that form walls.

[0019] According to the considered embodiments, the number of fixed sectors is even and they are arranged symmetrically on either side of the generator's longitudinal axis, or the fixed sectors are arranged asymmetrically with respect to the generator's longitudinal axis.

[0020] Preferably, the heat engine is a gas turbine or an internal combustion engine.

[0021] Advantageously, the rotor has one of the following magnetizations: radial, parallel, or Halbach type, and the stator has a diametrical winding or a concentric winding. Attached Figure Description

[0022] Other features and advantages of the invention will be better revealed by the following description, taken in conjunction with the accompanying drawings, which illustrate non-limiting embodiments of the invention, wherein:

[0023] Figure 1 is a schematic diagram of an aircraft turbine generator.

[0024] Figure 2 shows two half-views of a longitudinal section along an aircraft turbine generator according to the first and second exemplary embodiments of the present invention.

[0025] Figure 3 shows two half-views of a longitudinal section of an aircraft turbine generator according to the third and fourth exemplary embodiments of the present invention.

[0026] Figures 4A-4B show two views along a cross section of an aircraft turbine generator according to the fifth and sixth exemplary embodiments of the present invention.

[0027] Figures 5A-5B show first and second examples of the mechanical connection of the fixed sector winding of the generator in Figure 4, and

[0028] Figure 6 shows an unfolded view of the end of an aircraft turbine generator according to a seventh exemplary embodiment of the present invention. Detailed Implementation

[0029] Figure 1 schematically shows a system for generating electrical power P in an aircraft, which includes a generator 10 mechanically connected to a heat engine 12 via a drive shaft 14, the drive shaft itself being connected to the aircraft's propellant charge 16.

[0030] In aircraft, more specifically in those with hybrid electric propulsion, the heat engine is typically a gas turbine, and the assembly consisting of the gas turbine and a generator constitutes what is generally called an aircraft turbine generator. In some more specific areas, the heat engine can also be an internal combustion engine, such as a diesel engine.

[0031] A gas turbine typically includes a compressor with one or more (axial or centrifugal) stages, one or more combustion chambers, and a power turbine with one or more (radial or centrifugal) stages, which may or may not include a free turbine. When it includes this type of free turbine, the free turbine and generator are mounted on the same drive shaft, which is concentric with a shaft called the high-pressure shaft, supporting the compressor and power turbine. This shaft also supports a starter / generator for starting the gas turbine. When the gas turbine is of the linked turbine type, the drive shaft is directly formed by the high-pressure shaft. In the following description, drive shaft 14 can therefore refer to one or the other of these two gas turbine constructions, or even the output shaft of an internal combustion engine.

[0032] According to the present invention, and as shown in Figures 2 and 3, the generator 10 includes a longitudinal axis XX', which defines an axial direction and a perpendicular radial direction. The generator 10 includes a permanent magnet rotor formed by a common magnetized rotor yoke 100 and a ring formed by a plurality of permanent magnets 102 with alternating polarities distributed around the common magnetized rotor yoke 100 (see enlarged view associated with the rotor). The rotor is sectored along the axial direction because the magnet rings are arranged in several consecutive annular rings (only three annular rings are shown for simplicity), which are independent of each other and can have the same dimensions along the axial direction as shown by the three annular rings 102A, 102B, 102C in the upper part of Figure 2, or have different dimensions as shown by the three annular rings 102A, 102B, 102C in the lower part of Figure 2. The plurality of permanent magnets thus define an axially distributed movable annular ring.

[0033] The sectorized permanent magnet rotor is surrounded by one or more stators. The stator is formed by a common magnetic stator yoke 200 and a plurality of windings 202 distributed along the common magnetic stator yoke 200 (see enlarged view associated with the stator).

[0034] A stator is configured to deliver different multiphase voltage levels that are independent of each other via electrical connection 204.

[0035] The stator is also sectored along the axial direction, with each axially fixed sector 202A, 202B, 202C, which may have the same orientation (see upper part of Figure 2) or no common orientation (see lower part of Figure 2), defining an axially distributed fixed sector. The dimensions of the axially distributed fixed sectors may be the same as the dimensions of the facing axially distributed movable annular ring rotor rings, as shown in Figure 2, or have different dimensions, as shown in Figure 3. Thus, in the upper part of Figure 3, two axially fixed sectors 202A, 202D correspond to three movable annular rings (assuming the same dimensions in this example), and in the lower part of Figure 3, a single or common fixed sector 202E corresponds to three movable annular rings, said sector 202E covering all portions of the movable annular rings. More generally, the rotor includes at least three movable annular rings, and the stator includes at least one fixed axial sector covering at least two movable annular rings.

[0036] The magnetization of the rotor's permanent magnet 102 can be radial, parallel, of Halbach type, or any other suitable structure, and the stator winding 202 can be of diametrical or concentric type.

[0037] Figures 4A and 4B illustrate two other exemplary embodiments of the invention, wherein the stator sectorization is no longer axial but circumferential, at least partially defining annular fixed sectors, while the rotor sectorization itself remains axial. In Figure 4A, the circumferential sectors are symmetrical because the number of fixed sectors 204A-204F is even (six in the illustrated example, which should not be considered limiting) and they are arranged symmetrically on either side of the generator's longitudinal axis XX'. In Figure 4B, the circumferential sectors are asymmetrical because the fixed sectors 206A-206F, which can be even in number (six in the illustrated example), are arranged asymmetrically relative to the generator's longitudinal axis XX', i.e., no particular symmetry about the rotor is required. Each sector is associated with an electrical connection that can deliver a specific multiphase voltage level. The stator assembly formed by the yoke 200, windings 202, and electrical connections 204 is supported by the motor frame 210.

[0038] As schematically shown in Figures 5A and 5B, mechanical retention of the windings can be provided by obstacles forming wall 208 or external anchor 209. In this second configuration, the motor frame consists only of an outer ring forming a retainer 220, and the stator is spaced by a simple air gap 230.

[0039] Finally, Figure 6 shows a final preferred exemplary embodiment, in which the axially fixed sector is also sectored in the circumferential direction. Thus, a first stator 240A (magnetic yoke, winding electrical connection) extending on a plurality of movable annular rings 102A, 102B is followed by a second stator 240B (magnetic yoke, winding electrical connection) also extending on a plurality of movable annular rings 102B, 102C, with a common movable annular ring 102B surrounded by a sectored stator to receive a portion of the first stator 240A and a portion of the second stator 240B.

[0040] According to the invention, at least two fixed sectors are arranged at an angle so as not to overlap each other and to cooperate with at least one movable annular ring to deliver at least two different voltage levels that are independent of each other.

[0041] It is important to note that all the architectures described above allow for the generation of N electrical units with N different phase voltages using a single turbine generator. Furthermore, the direct mechanical connection to the heat turbine shaft enables high speeds (considered high speeds), thus allowing for minimizing the generator's mass and eliminating the need for an alternator-starter in the case of a gas turbine of the linked turbine type (single shaft).

Claims

1. A turbine generator for hybrid electric aircraft propulsion, comprising: -heat engine - A generator, mechanically connected to the heat engine, and comprising a rotor and a stator. The rotor extends axially and includes a common magnetized rotor yoke comprising a plurality of permanent magnets defining at least three axially distributed movable annular rings. The stator includes a magnetic stator yoke, which includes multiple electrical windings defining axially distributed fixed sectors and / or circumferentially distributed fixed sectors. The feature is that at least two fixed sectors, including an axially covering at least two movable annular rings, are further arranged at an angle so as not to overlap each other, and thus deliver at least two different and independent voltage levels.

2. The turbine generator according to claim 1, characterized in that, At least one fixed sector has an axial dimension different from that of another fixed sector.

3. The turbine generator according to claim 1, characterized in that, A movable annular ring with a defined axial dimension corresponds to a fixed sector with a different axial dimension.

4. The turbine generator according to claim 2, characterized in that, A movable ring is associated with a portion of a fixed sector and a portion of another fixed sector.

5. The turbine generator according to claim 4, characterized in that, The fixed sectors are separated by simple air gaps or by barriers that form walls.

6. The turbine generator according to claim 1, characterized in that, The number of fixed sectors is even, and they are symmetrically arranged on either side of the generator's longitudinal axis.

7. The turbine generator according to claim 1, characterized in that, The fixed sectors are arranged asymmetrically with respect to the longitudinal axis of the generator.

8. The turbine generator according to any one of claims 1 to 7, characterized in that, The heat engine is a gas turbine.

9. The turbine generator according to any one of claims 1 to 7, characterized in that, The heat engine mentioned is an internal combustion engine.

10. The turbine generator according to any one of claims 1 to 7, characterized in that, The rotor has one of the following magnetizations: radial, parallel, or Halbach type.

11. The turbine generator according to any one of claims 1 to 7, characterized in that, The stator has a diameter winding or a concentric winding.

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