Energy transmission system for contactlessly transmitting electric energy into an excitation winding of a rotor

Abstract

The invention relates to an energy transmission system, in the form of a rotary transformer, for contactlessly transmitting electric energy into an excitation winding (6) of a rotor (5) of an electric machine (1), having a rotational axis (14). The rotary transformer has a static primary unit (11) and a secondary unit (15) which can rotate with the rotor. The secondary unit (15) has a secondary winding (16), wherein the secondary winding (16) of the secondary unit (15) is in the form of an air coil, thus the secondary unit (15) does not have a secondary core. Additionally, at least one secondary shield (17, 17.1, 17.2) for shielding the magnetic field is provided on the secondary unit (15) in order to partly compensate for the degraded magnetic flux guidance.

Description

[0001] Description

[0002] title

[0003] Energy transfer system for the contactless transmission of electrical energy into a field winding of a rotor

[0004] State of the art

[0005] The invention is based on an energy transmission system for the contactless transmission of electrical energy into an excitation winding of a rotor according to the preamble of the main claim.

[0006] WO10105764 A1 already discloses an energy transmission system comprising a static primary unit and a secondary unit rotatable about a transmission axis. The secondary unit has a secondary winding support and a secondary winding arranged on the secondary winding support. A disadvantage is that the speed stability of the secondary unit is comparatively low, since the secondary unit includes a ferrite core for flux conduction, and ferrite cores have low strength values.

[0007] Advantages of the invention

[0008] The energy transfer system with the characterizing features of the main claim has the advantage that the speed stability of the secondary unit can be increased by eliminating the secondary core.

[0009] This is achieved according to the invention in that the secondary winding of the secondary unit is designed as an air-core coil and the secondary unit is designed without a secondary core, and in that at least one secondary shield is provided on the secondary unit to shield the magnetic flux. Due to the air-core coil, the (active) magnetic flux guidance through the secondary core is eliminated and the so-called coupling factor is reduced. In order to prevent magnetic flux from flowing into adjacent components outside the magnetic circuit and causing losses there due to the lack of flux guidance, at least one secondary shield is provided, which limits the magnetic flux to the outside of the shield and is thus intended to guide the magnetic flux at least indirectly. Advantageous further developments and improvements of the energy exchange system specified in the main claim are possible through the measures listed in the subclaims.

[0010] It is very advantageous if the secondary winding of the secondary unit is arranged on a secondary winding carrier having a hub opening in which a hub sleeve for torque transmission is fastened, in particular in a form-fitting and / or force-fitting manner, wherein a circumferentially encircling first secondary shield, in particular made of copper or aluminum, is provided between the secondary winding and the hub sleeve, in particular between the hub opening of the secondary winding carrier and the hub sleeve. In this way, a shielding of the magnetic flux toward the rotor shaft is achieved on the secondary side, so that no or less magnetic flux flows toward the rotor shaft. This makes it possible to achieve a sufficient coupling factor and a sufficient inductance in the transformer of the energy transmission system.

[0011] According to an advantageous embodiment, the first secondary shield may be a separate sleeve, a foil or a coating formed on the hub sleeve or on the hub opening.

[0012] In this way, the first secondary shielding can be implemented easily and cost-effectively.

[0013] According to an advantageous first embodiment, a first secondary shield, designed as a separate sleeve or as a coating, can have at least one projection or at least one recess for a positive connection to the secondary winding support. In this way, the first secondary shield is positively connected to the secondary winding support, allowing a higher torque to be transmitted from the rotor shaft to the secondary winding support. In the case of the first embodiment, the secondary winding support is, for example, molded onto the hub sleeve.

[0014] According to an advantageous second embodiment, the hub sleeve can have a surface structure, in particular a knurling or grooved pattern, on an outer side facing the secondary winding support, the secondary winding support is injection-molded onto the hub sleeve, and the first secondary shield, designed as a film, is embossed onto the surface structure by the injection-molded plastic. In this way, a positive connection can be created that withstands the loads arising from inertia, acceleration, or vibration.

[0015] It is further advantageous if a circuit board with a rectifier circuit for generating a DC voltage for the excitation winding of the rotor is provided on the secondary winding support, wherein a second secondary shield is provided in the circuit board according to a first embodiment or, according to a second embodiment, for example, as a separate element on a side of the circuit board facing the secondary unit. The second secondary shield can be made, in particular, of copper or aluminum and / or, in particular, as a layer, foil, or disc. In this way, shielding of the magnetic flux to one of the two end faces of the secondary winding support is achieved.

[0016] It is also advantageous if the circuit board has several superimposed copper layers, each of which includes conductor tracks to form the rectifier circuit, wherein the circuit board has at least one further copper layer, in particular several copper layers, which is not part of the rectifier circuit and forms the second secondary shield. In this way, the second secondary shield is integrated into the circuit board, thereby saving installation space and reducing manufacturing costs.

[0017] It is also advantageous if the at least one additional copper layer provided as shielding extends in the circuit board in the shape of a ring disk. This creates a large-area second secondary shield in the circuit board.

[0018] It is also advantageous if the secondary winding support has a recess for accommodating the circuit board. This allows the circuit board to be secured in the recess and supported against the centrifugal forces acting upon it.

[0019] The invention further relates to an energy transfer system with a secondary unit according to the invention and with a primary unit that interacts with the secondary unit. A primary shield, which is particularly made of aluminum or copper and is particularly part of a transformer housing for accommodating the primary unit, can be provided on the outer sides of a primary core of the primary unit facing away from the secondary unit. This shield is particularly made of aluminum or copper and is particularly part of a transformer housing for accommodating the primary unit. In this way, the shielding in the energy transfer system is further completed to achieve a largely closed shield.

[0020] Furthermore, it is advantageous if a core leg of the primary core extends beyond an outer circumference of the secondary unit in the radial direction with respect to the transformer axis towards the transformer axis and, for example, extends to a maximum of an outer bearing diameter of the rotary bearing less a joining clearance.

[0021] In this way, the magnetic flux is guided sufficiently well.

[0022] The invention also relates to an electrical machine with a rotor and an excitation winding arranged on the rotor, and with an energy transfer system according to the invention for the contactless transmission of electrical energy to the excitation winding of the rotor. The secondary unit of the energy transfer system is arranged on a rotor shaft of the electrical machine and is rotationally fixedly connected to it.

[0023] A flange sleeve, particularly made of aluminum or copper, is advantageously provided on the rotor shaft as a third secondary shield. This flange sleeve, axially adjacent to the hub sleeve of the secondary unit with respect to a rotor axis, and radially extending to an inner circumference of a housing opening of a transformer housing of the energy transfer system with respect to the rotor axis, is provided. In this way, the shielding in the energy transfer system is further completed, resulting in a largely closed shield.

[0024] drawing

[0025] Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.

[0026] Shown are: Fig.1 an electrical machine with an energy transmission system according to the invention,

[0027] Fig.2 shows in section a detail A according to Fig.1 according to a first embodiment and Fig.3 shows in section the detail A according to Fig.1 according to a second embodiment.

[0028] Description of the embodiments

[0029] Fig.1 shows a section through an electrical machine with an energy transmission system according to the invention.

[0030] The electrical machine 1 can be an electrically excited synchronous machine having a stator 2 with a stator winding 3 and a rotor 5 rotatable about a rotor axis 4 with an excitation winding 6.

[0031] The energy transmission system 10 of the electrical machine 1 can also be referred to as a rotary transformer and serves for the contactless transmission of electrical energy into the excitation winding 6 of the rotor 5.

[0032] The energy transmission system 10 comprises a static primary unit 11 and a secondary unit 15 rotatable about a transmission axis 14.

[0033] The secondary unit 15 of the energy transmission system 10 is arranged, for example, on a rotor shaft 7 of the electric machine 1 and is connected in a rotationally fixed manner to the rotor shaft 7.

[0034] The transformer axis 14 is in particular the rotor axis 4. The secondary unit 15 has a secondary winding 16 for inductive interaction with a primary winding 12 of the primary unit 11.

[0035] The primary unit 11 and the secondary unit 15 are arranged concentrically to each other, for example, wherein the secondary unit 15 is, for example, an internal rotor.

[0036] According to the invention, it is provided that the secondary winding 16 of the secondary unit

[0037] 15 is designed as an air-core coil, i.e. the secondary unit 15 is designed without a secondary core, and at least one secondary shield 17 is provided on the secondary unit 15 to shield the magnetic flux. Due to the air-core coil, the (active) magnetic flux guidance through the ferrite is eliminated, and the so-called coupling factor is reduced. In order to prevent magnetic flux from flowing into adjacent components outside the magnetic circuit and causing losses there due to the lack of flux guidance, at least one secondary shield 17 is provided, which limits the magnetic flux to the outside of the shield 17 and is thus intended to guide the magnetic flux at least indirectly.

[0038] The secondary winding 16 of the secondary unit 15 is arranged on a secondary winding support 20 having a hub opening 21. A hub sleeve 22, in particular made of steel, is fastened in the hub opening 21 for torque transmission and transmission of inertia forces, in particular in a form-fitting and / or force-fitting manner.

[0039] A circumferentially extending first secondary shield 17.1, particularly made of copper or aluminum, is provided between the secondary winding 16 and the hub sleeve 22, in particular between the hub opening 21 of the secondary winding support 20 and the hub sleeve 22. The first secondary shield 17.1 can be a separate sleeve, a foil, or a layer or coating formed on the hub sleeve 22 or on the hub opening 21. The first secondary shield 17.1, embodied as a coating, can be formed, for example, on an outer circumference of the hub sleeve 22.

[0040] According to a first embodiment shown in Fig.1, a first secondary shield 17.1 designed as a separate sleeve or as a coating can have at least one projection or at least one recess 18 for positive connection to the secondary winding carrier 20.

[0041] According to a second embodiment not shown in Fig. 1, the hub sleeve 22 can have a surface structure, in particular a knurling or grooving, on an outer side facing the secondary winding support 20, and the secondary winding support 20 can be injection-molded onto the hub sleeve 22, wherein the first secondary shield 17.1, designed as a film, is embossed onto the surface structure by the injection-molded plastic. The secondary winding support 20 is made of plastic, for example. According to Fig. 1, the secondary winding support 20 has, for example, a rotor sleeve 25 for radially supporting the secondary winding 16.

[0042] A circuit board 23 with a rectifier circuit for generating a DC voltage for the excitation winding 6 of the rotor 5 can be provided on the secondary winding support 20. The secondary winding support 20 can have a recess 24 for receiving the circuit board 23. The circuit board 23 can, for example, be annular disk-shaped.

[0043] On the outer sides of a primary core 30 of the primary unit 11 facing away from the secondary unit 15, a primary shield 31 can be formed, which is in particular made of aluminum or copper and is in particular part of a transformer housing 32 for accommodating the primary unit 11. The transformer housing 32 comprises, for example, a pot-shaped housing part 32.1 and a cover-shaped housing part 32.2 and is fastened, for example, to a housing 8 of the electrical machine 1, in particular to a bearing plate 9. According to the exemplary embodiment, the primary shield 31 is therefore formed by the pot-shaped housing part 32.1 and the cover-shaped housing part 32.2.

[0044] The primary core 30 of the primary unit 11 has, for example, a U- or L-shaped cross-section extending around the transformer axis 4, 14 and can be constructed in one piece or in multiple pieces. The primary core 30 is, in particular, a ferrite core comprising ferrite.

[0045] A core leg 33 of the primary core 30 extends radially relative to the transformer axis 4, 14 beyond an outer circumference 15a of the secondary unit 15. The recess 24 for receiving the circuit board 23 is arranged in particular on a side of the secondary winding support 20 facing away from the core leg 33.

[0046] The primary winding 12 is arranged in the radial direction with respect to the transformer axis 14 between a circumferential section 30u of the primary core 30 and a primary winding support 34. The primary winding support 34 has an inner support circumference 34u facing away from the primary winding 12, which encloses an installation space for the secondary unit 15 and forms a first mounting opening 27 for axially inserting the secondary unit 15. The first core leg 33 of the primary core 30 forms a second mounting opening 28 for the passage of a rotary bearing 29 for supporting the rotor 5 of the electric machine 1. The bearing plate 9 of the housing 8 has a bearing receptacle 9.1 for receiving the rotary bearing 29.

[0047] The second mounting opening 28 is smaller in the radial direction with respect to the transmitter axis 14 than the first mounting opening 27. The cover-shaped housing part 32.2 has a housing opening 35 for the passage of the pivot bearing 29.

[0048] A second secondary shield 17.2 can be formed in the circuit board 23 or on a side of the circuit board 23 facing the secondary unit 15, which shield is made in particular of copper or aluminum and / or in particular as a layer, foil or disc.

[0049] A flange sleeve 40, in particular made of aluminum or copper, is provided on the rotor shaft 7 as a third secondary shield. The flange sleeve 40 is adjacent to the hub sleeve 22 of the secondary unit 15 in the axial direction relative to a rotor axis 4 and extends radially relative to the rotor axis 4 toward an inner circumference 35i of the housing opening 35 of the transformer housing 32, 32.2 of the energy transfer system 10. The flange sleeve 40 is connected, for example, in a rotationally fixed manner to the rotor shaft 7.

[0050] Fig.2 shows in section a detail A according to Fig.1 according to a first embodiment.

[0051] According to the first embodiment, the second secondary shield 17.2 is provided on a side of the circuit board 23 facing the secondary unit 15, for example as a separate element or as a coating.

[0052] Fig.3 shows in section the detail A of Fig.1 according to a second embodiment.

[0053] According to the second embodiment, the second secondary shield 17.2 is integrated in the circuit board 23.

[0054] The circuit board 23 conventionally has several superimposed

[0055] Copper layers 36, which each comprise conductor tracks 37 to form the rectifier circuit. To integrate the second secondary shield 17.2 into the circuit board 23, the circuit board 23 has, according to the invention, at least one further copper layer 38, in particular several copper layers 38, which are not part of the

[0056] Rectifier circuit, i.e., it is not electrically connected to the rectifier circuit. The at least one additional copper layer 38 provided as shielding extends in the circuit board 23, for example, in the shape of an annular disk.

Claims

Claims 1 . Energy transmission system, in particular a rotary transformer, for the contactless transmission of electrical energy into an excitation winding (6) of a rotor (5) of an electrical machine (1), comprising a static primary unit (11) and a secondary unit (15) rotatable about a transformer axis (14), wherein the secondary unit (15) has a secondary winding (16), characterized in that the secondary winding (16) of the secondary unit (15) is designed as an air coil and the secondary unit (15) is designed without a secondary core and in that at least one secondary shield (17) of the magnetic field is provided on the secondary unit (15).

2. Energy transmission system according to claim 1, characterized in that the secondary winding (16) of the secondary unit (15) is arranged on a secondary winding carrier (20) which has a hub opening (21) in which a hub sleeve (22) for torque transmission is fastened, in particular in a form-fitting and / or force-fitting manner, wherein a first secondary shield (17.1), in particular made of copper or aluminum, running around the circumference is provided between the secondary winding (16) and the hub sleeve (22), in particular between the hub opening (21) of the secondary winding carrier (20) and the hub sleeve (22).

3. Energy transfer system according to claim 2, characterized in that the first secondary shield (17.1) is a separate sleeve, a film or a coating formed on the hub sleeve (22) or on the hub opening (21).

4. Energy transfer system according to claim 3, characterized in that the first secondary shielding (17.1) designed as a separate sleeve or as a coating has at least one projection (18) or at least one recess (18) for positive connection to the secondary winding carrier (20).

5. Energy transmission system according to claim 3, characterized in that the hub sleeve (22) has a surface structure, in particular a knurling or grooving, on an outer side facing the secondary winding carrier (20), that the secondary winding carrier (20) is connected to the hub sleeve (22) is injection-molded and that the first secondary shielding (17.1) designed as a film is embossed onto the surface structure by the injection-molded plastic.

6. Energy exchange system according to one of the preceding claims, characterized in that a circuit board (23) with a rectifier circuit for generating a DC voltage for the excitation winding (6) of the rotor (5) is provided on the secondary winding carrier (20), wherein a second secondary shield (17.2) is provided in the circuit board (23) or on a side of the circuit board (23) facing the secondary unit (15), which second secondary shield is designed in particular from copper or aluminum and / or in particular as a layer, foil or disc.

7. Energy transfer system according to claim 6, characterized in that the circuit board (23) has a plurality of superimposed copper layers (36), each of which comprises conductor tracks (37) to form the rectifier circuit, wherein the circuit board (23) has at least one further copper layer (38), in particular a plurality of copper layers (38), which is not part of the rectifier circuit and forms the second secondary shield (17.2).

8. Energy transmission system according to claim 7, characterized in that the at least one further copper layer (38) provided as shielding extends in the circuit board (23) in the form of an annular disk.

9. Energy transfer system according to one of claims 6 to 8, characterized in that the secondary winding carrier (20) has a recess (24) for receiving the circuit board (23).

10. Energy transmission system according to one of the preceding claims, characterized in that a primary shield (31) is provided on the outer sides of a primary core (30) of the primary unit (11) facing away from the secondary unit (15), which shield is in particular made of aluminum or copper and is in particular part of a transmitter housing (32) for receiving the primary unit (11).

11. Energy transfer system according to claim 10, characterized in that a core leg (33) of the primary core (30) is radially arranged with respect to the Transformer axis (4,14) extends beyond an outer circumference (15a) of the secondary unit (15) towards the transformer axis (4,14).

12. Electrical machine with a rotor (5) and an excitation winding (6) on the rotor (5) and an energy transmission system (10) for the contactless transmission of electrical energy into the excitation winding (6) of the rotor (5) according to one of the preceding claims, wherein the secondary unit (15) of the energy transmission system (10) is arranged on a rotor shaft (7) of the electrical machine (1).

13. Electrical machine according to claim 12, characterized in that a flange sleeve (40), in particular made of aluminum, is provided on the rotor shaft (7) as a third secondary shield, which adjoins the hub sleeve (22) of the secondary unit (15) in the axial direction with respect to a rotor axis (4) and extends in the radial direction with respect to the rotor axis (4) to an inner circumference (35i) of a housing opening (35) of a transformer housing (32) of the energy transformer system (10).

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