DE102022207340B3 - Rotor arrangement for a separately excited synchronous machine - Google Patents

Abstract

A rotor arrangement (1) for a separately excited synchronous machine. The rotor arrangement comprises a rotor shaft (2) designed as a hollow shaft for at least one field winding, a transformer (5) arranged within the rotor shaft (2) for the contactless transmission of a current required for rotor field generation to the field winding, the transformer (5) having a stator-fixed primary side and has a secondary side non-rotatably coupled to the rotor shaft, and a rectifier (14) arranged within the rotor shaft (2) and electrically coupled between the secondary side of the transformer (5) and the field winding. The secondary side of the transformer (5) and the rectifier (4) are coupled to one another via an axial, electrically conductive press-fit connection (22).

Description

The present invention relates generally to electrical machines and in particular to rotor arrangements for separately excited synchronous machines.

Externally excited synchronous machines as drives for vehicles, such as cars, use conductive transmission devices to transfer the current required to generate a rotor field from a stationary to a rotating system. These can be designed, for example, as carbon brush or slip ring arrangements. In addition, non-contact transmission devices are also known, which are based in particular on inductive transmission. These are essentially transformers whose primary and secondary sides are separated from each other by an air gap and designed to rotate against each other. There is also a rectifier circuit on the secondary side to convert the alternating current necessary for transmission into a direct current necessary for generating a magnetic field.

In comparison to a permanently excited synchronous machine, a separately excited synchronous machine requires, among other things, an excitation winding on the rotor and a transmission device for the current from the stationary system to the rotor instead of permanent magnets in the rotor. One challenge is to design and arrange the transmission device in particular in such a way that no or as little as possible additional length of the electrical machine (e-machine) results. Another challenge is that in previously known solutions, the installation space below the winding heads of the stator winding is usually used for the arrangement of the transformer or the rectifier electronics and, on the one hand, there are high temperatures starting from the winding heads and, on the other hand, cooling is difficult. Additional seals and encapsulations should also be avoided for efficiency and cost reasons.

For example, the prior art is out DE 10 2020 216 485 A1 a rectifier for a separately excited electric machine is known. Next is over, for example DE 40 12 546 A1 a contactless resolver for a rotor is known.

There is therefore a need for non-contact transmission systems for separately excited synchronous machines with a short overall length and good cooling options.

This need is taken into account by rotor arrangements and externally excited synchronous machines according to the independent claims. Advantageous further training is the subject of the dependent claims.

A rotor arrangement for a separately excited synchronous machine is proposed. The rotor arrangement comprises a rotor shaft designed as a hollow shaft for at least one field winding. A transformer is arranged within the rotor shaft for the contactless transmission of a current required for rotor field generation to the field winding. The transformer has a primary side that is fixed to the stator and a secondary side that is coupled in a rotationally fixed manner to the rotor shaft. A rectifier electrically coupled between the secondary side of the transformer and the field winding is also arranged within the rotor shaft. The secondary side of the transformer and the rectifier are coupled to one another via an axial electrically conductive press-fit connection. The proposed solution therefore envisages arranging an inductive energy transmission device (transformer) within the hollow shaft of the electric machine. Transformer and rectifier can be connected to one another mechanically and electrically using a releasable press-fit connection. This makes it possible to achieve significant savings in installation space and facilitate installation and removal.

According to some embodiments of the present invention, the rectifier has a carrier for rectifier diodes. The carrier (substrate) can be designed to be rotationally symmetrical. At least one axial electrically conductive contact pin of the press-fit connection electrically couples a secondary-side winding of the transformer to a metallized plated-through hole on the carrier. The transformer can therefore be connected to the rectifier using an axial contact pin.

According to some exemplary embodiments of the present invention, the carrier has an electrically conductive stamped connecting element (stamped grid) for electrically connecting the secondary side of the transformer to the rectifier diodes. The lead frame can, for example, be used as an alternative or in addition to a circuit board.

According to some embodiments of the present invention, the carrier of the rectifier diodes has a circuit board as a substrate for the rectifier diodes. The circuit board can be designed to be rotationally symmetrical (e.g. circular or ring-shaped).

According to some embodiments of the present invention, the circuit board is designed as an IMS Circuit board (Insulated Metal Substrate) is formed and / or has vias (through-contacts) to transport heat away from the rectifier. IMS PCBs are also called metal core PCBs. A metal core or metallic vias each offer good thermal conductivity.

According to some embodiments of the present invention, the rectifier diodes of the rectifier are designed as SMD components (SMD = Surface Mounted Device). Alternatively, the rectifier diodes can also be designed as THT components (THT = through-hole technology).

According to some exemplary embodiments of the present invention, the carrier and the rectifier diodes are designed to be cast with a casting compound. As a result, a high mechanical stability of the rectifier can be achieved, particularly when the rotor arrangement rotates.

According to some exemplary embodiments of the present invention, the casting compound has a thermal conductivity higher than 2 W/mK, preferably higher than 10 W/mK. This means that heat can also be removed from the rectifier via the casting compound.

According to some exemplary embodiments of the present invention, the rectifier has at least one clamping socket in order to electrically couple the rectifier on the output side to the exciter or rotor winding via at least one radial connection line. Such a clamping socket can be used to simplify the installation or removal of the transformer and rectifier into or out of the rotor shaft.

According to some embodiments of the present invention, the rectifier includes a heat sink formed at an axial end of the rectifier or radially surrounding rectifier diodes of the rectifier. Heat can then be dissipated from the rectifier via this heat sink.

According to some exemplary embodiments of the present invention, a primary-side and a secondary-side winding of the transformer are each designed as a flat strip winding. This allows the transformer to be radially compact.

According to some exemplary embodiments of the present invention, the transformer within the rotor shaft can have a primary side that is fixed to the stator and a secondary side that can be rotated about an axis of rotation and is coupled in a rotationally fixed manner to the rotor shaft. The primary side of the transformer arranged within the rotor shaft can therefore be coupled to the stationary system of the externally excited synchronous machine, while the secondary side of the transformer is coupled to the rotatable rotor shaft.

According to some exemplary embodiments of the present invention, the rotor arrangement can further have a stator-fixed support which projects axially into a cavity of the rotor shaft and is mechanically coupled to the primary side of the transformer. The carrier for the primary side of the transformer can, for example, be lance-shaped and carry or support the primary side of the transformer on its outer circumference.

According to some exemplary embodiments of the present invention, the transformer can comprise a stator-fixed, primary-side ferrite core, in which a primary-side winding of the transformer is inserted. The transformer can also include a secondary-side ferrite core that is rotatable relative to the primary-side ferrite core and is coupled to the rotor shaft in a rotationally fixed manner, in which a secondary-side winding of the transformer is inserted. In addition to ferrite, other soft magnetic materials that increase inductance are of course also conceivable for coil cores.

According to some embodiments of the present invention, the field winding (rotor winding) may extend axially from an initial region to an end region along the rotor shaft. The transformer (and possibly also the rectifier) can be arranged axially between the initial region and the end region of the field winding within the rotor shaft. This means that axial installation space can be advantageously saved.

According to some embodiments of the present invention, an outer diameter of a housing of the transformer and an outer diameter of a housing of the rectifier are adapted to an inner diameter of the rotor shaft. A press fit of the transformer and the rectifier within the rotor shaft can thus be achieved.

A separately excited synchronous machine is also proposed, which includes a rotor arrangement according to one of the previous exemplary embodiments.

• 1 eine Rotoranordnung für eine fremderregte Synchronmaschine gemäß einem Ausführungsbeispiel;
• 2 eine Ausführung einer Klemmverbindung eines inneren Ferritkerns;
• 3 ein Ausführungsbeispiel einer Baugruppe aus Übertragereinrichtung und Gleichrichteranordnung im montierten Zustand;
• 4 die Anordnung der 3 in Explosionsdarstellung;
• 5 ein weiteres Ausführungsbeispiel einer Gleichrichteranordnung im montierten Zustand;
• 6 die Anordnung der 5 in Explosionsdarstellung;
• 7,8 ein weiteres Ausführungsbeispiel einer Baugruppe aus Übertragereinrichtung und Gleichrichteranordnung; und
• 9,10 ein weiteres Ausführungsbeispiel einer Baugruppe aus Übertragereinrichtung und Gleichrichteranordnung.

Individual embodiments of the present invention are described below using the figures as examples. Show it:

• 1 a rotor arrangement for a separately excited synchronous machine according to an exemplary embodiment;
• 2 an embodiment of a clamp connection of an inner ferrite core;
• 3 an exemplary embodiment of an assembly consisting of a transformer device and a rectifier arrangement in the assembled state;
• 4 the arrangement of the 3 in exploded view;
• 5 a further exemplary embodiment of a rectifier arrangement in the assembled state;
• 6 the arrangement of the 5 in exploded view;
• 7 , 8th a further exemplary embodiment of an assembly consisting of a transformer device and a rectifier arrangement; and
• 9 , 10 a further exemplary embodiment of an assembly consisting of a transformer device and a rectifier arrangement.

A synchronous machine is a rotating electrical machine in which the rotor (also called rotor) runs synchronously with a rotating field of the stator (also called stator). Synchronous machines are often designed as three-phase machines, i.e. as three-phase synchronous machines. The synchronous machine gets its name because of the operating characteristic that its rotor rotates exactly synchronously with the rotating field specified by a mains frequency.

A constant magnetic field is generated in the rotor. This happens either through a permanent magnet (permanently excited) or through external electromagnetic excitation (externally excited). Depending on the design of the synchronous machine, the rotor can be designed as a salient pole rotor or a solid pole rotor. In contrast, a rotating magnetic field is generated in the stator, for example by generating this rotating field using three-phase alternating current. For this purpose, three inductors offset by 120° can be installed in the stator. It goes without saying that more or fewer phases can also be used.

In principle, every synchronous machine can be operated as an electric motor and electric generator. When the synchronous machine is operated as a generator, the rotor is driven externally mechanically. If it is a separately excited rotor, it must be excited accordingly. The rotor's magnetic field periodically induces a voltage in the stator windings. This voltage is called the pole wheel voltage. When the motor is operating, a three-phase alternating voltage, for example, is applied to the synchronous machine from outside. The resulting magnetic rotating field of the stator sets the rotor in motion. The machine can thereby drive an external mechanical load, such as a motor vehicle.

The present invention relates to rotor arrangements for externally excited synchronous machines, which can be used, for example, in (partially) electrically operated motor vehicles.

1 shows a rotor arrangement 1 for a separately excited synchronous machine according to an exemplary embodiment of the present invention.

The exemplary rotor arrangement 1 comprises a rotor shaft 2 designed as a hollow shaft. The rotor shaft 2 can carry at least one field winding or rotor winding (not shown) on its outer circumference by means of a rotor laminated core 3. An inductive transmission device 5 (transformer) is arranged within the hollow rotor shaft 2 for the contactless (inductive) transmission of a current required for rotor field generation to the at least one field winding. By arranging the inductive transmission device 5 within the rotor shaft 2, installation space can be advantageously saved.

In the 1 Rotor arrangement 1 shown is essentially formed by the hollow rotor shaft 2, on the outer circumference of which the rotor laminated core 3 is arranged. One or more rotor field windings inserted into the rotor laminated core 3 are in 1 not shown. Also not shown are fixed stator windings of the externally excited synchronous machine arranged radially outside the rotor arrangement 1 or the rotor laminated core 3.

The rotor laminated core 3 arranged on the outer circumference of the rotor shaft 2 extends axially from an initial region (left) to an end region (right) along the rotor shaft 2. In the initial region (left) of the rotor laminated core 3, a shaft shoulder can be provided on the outer circumference of the rotor shaft 2 as an axial stop for the rotor laminated core 3 may be provided. In the exemplary embodiment shown, the transformer 5 is arranged axially between the initial region and the end region of the rotor laminated core 3 within the rotor shaft 2. As a result, no additional axial installation space is required for the transformer 5. However, it is understood that the transformer 5 could in principle also be arranged at other axial positions within the rotor shaft 2, such as axially (left or right) outside the rotor laminated core 3 or axially only partially overlapping with the rotor laminated core 3.

In the exemplary embodiment shown, inside the rotor shaft 2 there is a stator-fixed oil lance 4, which extends from a first axial end (left) of the rotor shaft 2 protrudes in the axial direction (to the right) into the cavity of the rotor shaft 2 and which, for example, can guide cooling oil into the rotor shaft 2. Coolants other than oil (such as air, water, or another coolant) are also conceivable. Oil has the advantage that it can also act as a lubricant. In the present case, towards the first axial end (left) of the rotor shaft 2, a first (inner) diameter of the oil lance 4 is designed to be larger than a second (inner) diameter of the oil lance 4 towards an opposite second axial end (right) of the rotor shaft 2. By narrowing from the first (inner) diameter to the second (inner) diameter of the oil lance 4, a pressure of the cooling oil flowing into the rotor shaft 2 can be increased. This can have an advantageous effect on the flow speed of the oil and thus its cooling effect.

Furthermore, in the exemplary embodiment shown, the oil lance 4 also serves as a support for a stator-fixed primary side of the transformer 5. In the exemplary embodiment shown, the transformer 5 located inside the rotor shaft 2 has a stator-fixed, primary-side ferrite core 6, in which a primary-side winding 10 of the transformer 5 is inserted. This can, for example, be designed as a flat band or HF stranded winding (HF = high frequency) and can be surrounded by a winding support 11 on the primary side. The primary-side winding carrier 11 can have the task of keeping the primary-side winding 10 in shape during assembly and, for safety reasons, providing increased electrical insulation of the winding package relative to the primary-side ferrite core 6 and thus the stator (not shown). The primary-side ferrite core 6 is mechanically firmly connected to the oil lance 4 and is therefore stator-proof. The primary-side ferrite core 6 is rotationally symmetrical and attached to an outer circumference of the oil lance 4. Furthermore, the primary-side ferrite core 6 can comprise an axial section and a section pointing radially outwards. In the in 1 In the exemplary embodiment shown, the axial section of the primary-side ferrite core 6 is firmly coupled to the outer circumference of the oil lance 4.

The second part of the transformer 5 comprises a secondary-side ferrite core 7 which is rotatable relative to the primary-side ferrite core 6 and is coupled in a rotationally fixed manner to the rotor shaft 2 on its inner circumference, in which a secondary-side winding 12 of the transformer 5 is inserted. This can also be designed as a flat strip or HF stranded winding and can be surrounded by a secondary winding support 13. The secondary-side winding carrier 13 can have the task of keeping the secondary-side winding 12 in shape during assembly and, for safety reasons, providing increased electrical insulation of the winding package relative to the secondary-side ferrite core 7 and thus the rotor. The secondary-side ferrite core 7 is mechanically connected to the rotor shaft 2 and is therefore rotor-proof. The secondary-side ferrite core 7 is rotationally symmetrical and attached to an inner circumference of the rotor shaft 2. Furthermore, the secondary-side ferrite core 7 can comprise an axial section and a section pointing radially inwards. In the in 1 In the exemplary embodiment shown, the axial section of the secondary-side ferrite core 7 is coupled in a rotationally fixed manner to the inner circumference of the rotor shaft 2. The windings 10 and 12 are framed by the axial and radial sections of the ferrite cores 6 and 7.

Since ferrite is brittle, as far as possible no tensile stresses should be introduced when assembling the rotor arrangement 1. The secondary-side ferrite core 7 inserted into the rotor shaft 2 can, for example, be pressed into the rotor shaft 2, since compressive stresses occur in the material. In this way, it can be optimally supported outwards by the rotor shaft 2 even under the influence of centrifugal force. However, the primary-side ferrite core 6 should not be pressed (shrunk) onto the oil lance 4 as it could break as a result of tensile stresses. Either an adhesive connection can be advantageous here, or a mechanical connection in which the primary-side ferrite core 6 is clamped axially or held via a positive fit.

The primary side or primary-side winding 10 of the transformer 5 can be electrically connected to an electrical inverter (not shown), which provides the alternating current necessary for the function of the transformer 5. The secondary side or secondary-side winding 12 can be electrically connected to a rectifier arrangement 14. This is necessary to convert the alternating current into a direct current, which is needed to build the rotor excitation field.

In the exemplary embodiment shown, the rectifier arrangement 14 coupled between the secondary side of the transformer 5 and the field winding is also arranged inside the hollow rotor shaft 2. In the exemplary embodiment shown, the rectifier arrangement 14 is also arranged axially between the initial region and the end region of the rotor laminated core 3 within the rotor shaft 2. As a result, no additional axial installation space is required for the rectifier arrangement 14. However, it is understood that the rectifier arrangement 14 could in principle also be arranged at other axial positions within the rotor shaft 2, such as axially (left or right). half of the rotor laminated core 3 or axially only partially overlapping with the rotor laminated core 3.

2 shows a schematic cross section through an exemplary embodiment of the rectifier arrangement 14.

The rectifier arrangement 14 here essentially comprises a rectifier housing 15, which can be inserted into the rotor shaft 2 and connected to it mechanically (rotatably), as well as electronic components, such as rectifier diodes 16. The secondary side (secondary-side winding) 12 of the transformer 5 and The rectifier arrangement 14 can be coupled to one another via an axial electrically conductive press-fit or press-in connection in order to establish an electrical connection between the rectifier arrangement 14 and the transformer 5. Press-in technology refers to a solderless connection technology in which one or more contact pins are pressed into a metallized hole (through-hole), for example on a circuit board of the rectifier arrangement 14. In the present case, the contact pins can be inserted into corresponding axial openings in the rectifier housing 15.

An outer circumference of the rectifier housing 15 is adapted to the inner circumference of the rotor shaft 2. In the present exemplary embodiment, an inner circumference of the rectifier housing 15 is polygonal (here: octagonal), so that the rectifier diodes 16 can be arranged on tangential surfaces inside the rectifier housing 15. The rectifier diodes 16 can be connected to the rectifier housing 15 via insulating pads 17 in an electrically insulating but thermally conductive manner that is as good as possible. The rectifier housing 15 can preferably be made of aluminum to ensure good dissipation of the waste heat generated by the rectifier diodes 16. By arranging the rectifier diodes 16 on tangential surfaces inside the rectifier housing 15, the components can be optimally supported against centrifugal force. The rectifier circuit is electrically connected to the field winding of the rotor on the secondary side, but this is not shown.

3 shows a further exemplary embodiment of an assembly consisting of a transformer device 5 and a rectifier arrangement 14 in the assembled state. 4 shows the same arrangement in an exploded view. The assembly is designed to be arranged within the rotor shaft 2. Transformer device 5 and rectifier arrangement 14 are arranged coaxially. The axial position of the assembly 5, 14 can either have an axial overlap with the field winding or the rotor laminated core 3 of the rotor or be axially adjacent to it.

The primary side of the transformer 5 is formed by the primary-side ferrite core 6 with the primary-side winding support 11 and the primary-side winding 10. The winding 10 is preferably designed as a flat strip winding. A primary-side axial contacting pin 18 is attached to both ends of the flat strip, for example by welding or soldering. The primary-side contacting pin 18 can be electrically connected to an electrical inverter (not shown), which provides the alternating current necessary for the function of the transformer 5. In terms of assembly technology, it is advantageous to pre-assemble the primary-side winding 10 on the primary-side winding support 11. By means of a primary-side winding potting 19, the primary-side winding 10 can be held mechanically, electrically insulated and protected from contamination.

The secondary side of the transformer 5 has an analogous structure with the secondary-side ferrite core 7 and the secondary-side winding 12 accommodated therein, which can also be designed as a flat strip winding. By means of a secondary-side winding casting 20, the secondary-side winding 12 can be held mechanically, electrically insulated and protected from contamination. The secondary-side ferrite core 7 can be provided with insulation 21 on parts of its outer contour, which decouples it thermally and electrically from the rotor shaft 2.

The primary and secondary-side ferrite cores 6, 7 can be inserted axially into one another, but are separated from one another axially and radially by air gaps, so that they can be rotated against each other without contact during operation of the rotor arrangement. The primary-side ferrite core 6 is connected to the stator and the secondary-side ferrite core 7 is connected to the rotor.

Attention is in the 3 to place on the area in which one or more axial contacting pins 22 of the secondary winding 12 axially penetrates the secondary side ferrite core 7. For this purpose, an axial through opening is provided on the inner circumference of the secondary-side ferrite core 7. There is also electrical insulation within the through opening between the secondary-side ferrite core 7 and the contacting pin or contact pin 22, so that the contact pin 22 and the secondary-side ferrite core 7 are electrically decoupled. The same applies to feedthroughs for other contact pins through the primary and secondary side ferrite core 6, 7. The contact pin 22 can be pressed with its axial end into a metallized hole (through-hole) in a circuit board 23 of the rectifier 14, so that an electrical connection between the secondary side winding 12 and circuit board 23 of the rectifier arrangement 14 can be produced.

The rectifier arrangement 14 can include a bridge circuit of, for example, four rectifier diodes 16. These can advantageously be designed as SMD components and arranged on the circuit board 23. As in 4 shown, the circuit board 23 can be annular. The rectifier diodes 16 can be arranged evenly on the circuit board 23 in the circumferential direction. The contacting of the rectifier circuit 14 or the circuit board 23 with the secondary-side winding 12 of the transformer device 5 is designed as a press-fit connection, with the axial contacting pins 22 of the secondary-side winding 12 being inserted into corresponding holes in the circuit board 23.

To contact the rectifier circuit 14 with the rotor winding of the separately excited synchronous machine (not shown), connection sockets 24 can be arranged on the circuit board 23. During assembly, 2 conductors can be inserted and clamped into these from the radial outside through corresponding radial openings in the rotor shaft.

A heat sink 25 can be arranged on a rear side of the circuit board 23 facing away from the transformer 5 and connected to the circuit board, for example by means of screws 26. As in 4 shown, the heat sink 25 can also be annular (at least in sections). To transfer the waste heat from the rectifier diodes 16 through the circuit board 22 to the heat sink 25, the circuit board 23 can have so-called vias (plated-through holes) 27. Alternatively, a so-called IMS circuit board with an integrated aluminum core can be used for better heat transfer to the heat sink 25. Electrical insulation of the back of the diode from the vias 27 can be achieved, for example, using paint, ceramic plates or the like (not shown). The heat sink 25 can, for example, be made of metal and/or have a thermally conductive ceramic.

To protect the diodes 16 from contact with surrounding cooling oil and possible contamination, the circuit board 23 can be cast or encapsulated with an electrically insulating casting compound 28 after the diodes 16 have been installed. In this way, the diodes 16 can also be held mechanically and protected against vibrations and centrifugal force.

At the in 3 and 4 In the exemplary embodiment shown, a (rotationally symmetrical) circuit board 23 serves as a carrier for the rectifier diodes 16 and the contacting elements between the rectifier circuit 14 and transformer 5 and between the rectifier circuit 14 and the rotor winding. The rectifier diodes 16 can be designed in an SMD version. The contact with the secondary-side winding 12 takes place via an axial press-fit connection. Windings 10, 12 of the transmission device 5 can be designed as flat strip windings with axial contacting pins 18, 22 at the ends of the strip. Contact with the rotor winding can take place via clamping bushings 24, into which a sword at the end of the rotor winding or the wire end of the rotor winding itself is inserted in the radial direction from the outside (at least one contact point for the rotor winding within the rotor shaft). A front side of the circuit board 23 facing the transformer 5 can be encapsulated or cast together with the rectifier diodes 16. A heat sink 25 can be provided on the back of the circuit board 23 and can be connected to the circuit board 23 by screws 26. The pitch circle of the screw connections can be smaller than the inner diameter of the secondary-side ferrite 7. For improved heat transfer, the circuit board 23 can be provided with vias 27 or designed in an IMS version. An electrically insulating encapsulation 21 of the secondary-side ferrite core 7 is used to insulate the rotor shaft 2. The assembly consisting of the transformer device 5 and the rectifier assembly 14 is divided into two (pre-assembled) sub-assemblies: the transformer assembly 5 and the rectifier assembly 14, which are directly assembled and spatially direct ( axial) can be positioned next to each other.

An alternative embodiment of the rectifier arrangement 14 is shown in 5 as well as an exploded view in 6 shown.

The rectifier arrangement 14 of 5 and 6 differs from that described above in that the heat sink 25 is omitted. Instead, the circuit board 23 and the diodes 16 can be overmolded with a special thermoset, which has a special material property of significantly increased thermal conductivity compared to conventional thermosets. Such materials are both the subject of research and already available on the market. The increased thermal conductivity is achieved, for example, by ceramic additives. A thermal conductivity of greater than 2 W/mK, but in particular greater than 10 W/mK, is advantageous. The overmolding thus combines the mechanical and chemical protection of the components with the function of heat dissipation and the heat sink. In this way, an axially front and axially rear thermal conductive potting 29 and 30 can be produced for the circuit board 23. This offers advantages in geometric design, saves a component and also makes it possible, in particular, to use the ladder plate 23 to be equipped on both sides as required 6 shown. This allows smaller diodes 16 to be used or a higher current carrying capacity to be achieved.

The circuit board 23 as a carrier for the rectifier diodes 16 can therefore be cast with a thermoset plastic with increased thermal conductivity. The potting 29, 30 combines electrical insulation, chemical protection, mechanical protection and heat dissipation in one. This is particularly interesting in combination with a circuit board populated on both sides.

Show another version 7 and 8th . Here the transmitter device 5 is as shown 3 designed in a known manner and coupled to the rectifier arrangement 14 by means of an axial press-fit connection. The rectifier arrangement 14 in turn comprises a (ring-shaped) circuit board 23, which provides conductor tracks of the rectifier circuit as well as electrical connections to the secondary side of the transformer device 5 and to the rotor winding (not shown). However, the rectifier diodes 16 are designed here in a so-called THT version (“through hole technology”) and are mounted standing on the back of the circuit board 23. Connection pins of the diodes 16 are, for example, soldered to the conductor tracks on the front of the circuit board 23. To protect the circuit board 23 and the contacts, a circuit board potting 31 is used axially between the transformer 5 and the circuit board 23. The circuit board potting 31 also surrounds the circuit board 23 radially.

The potting 31 is designed here so that it protrudes radially and axially around the outside of the circuit board 23 and also holds a heat sink 32 for the rectifier diodes 16 on its outer contour. The heat sink 32 surrounds the THT rectifier diodes 16 radially and has contact surfaces for the rectifier diodes 16 on its inside. The rectifier diodes 16 can thus be supported radially outwards by the heat sink 32 against the centrifugal force. The rectifier diodes 16 can be connected to the heat sink 32, for example via radial pins 33. Insulating elements 34 for electrical insulation can also be provided between the diodes 16 and the heat sink 32. On the outside of the heat sink 32, as in 8th visible, there is a wave or rib-shaped structure. On the one hand, this increases the surface area of the heat sink 32 in order to increase the release of heat, for example to the surrounding cooling oil. On the other hand, when the heat sink 32 is pressed into the hollow rotor shaft (not shown), the contact area between the shaft and the heat sink 32 is reduced and less heat is introduced from the shaft 2 into the heat sink 32.

Show another version 9 and 10 . The transformer device 5 is again constructed according to the known principle, but the rectifier arrangement 14 differs in its structure. Here a so-called component carrier 35 is used for the rectifier diodes 16 and the heat sink 32. The component carrier 35 comprises a base body 36 made of plastic and a lead frame 37 embedded in it. The base body 36 can therefore be formed by a plastic injection molding of the lead frame 37, represents electrical insulation of all conductors and mechanically supports the lead frame 37. The lead frame 37 forms the Conductor tracks for interconnecting the rectifier circuit with the diodes 16 and the contacts to the secondary winding 12 and to the rotor winding. In the present case, the axial contact pins 22 of the press-fit connection can be inserted into corresponding axial openings in the component carrier 35 and the lead frame 37. In addition, the component carrier 35 accommodates the heat sink 32 on its outer contour. This means that the component carrier 35 encompasses the heat sink 32 at least partially radially and axially. The diodes 16 can be clamped radially between the component carrier 35 and the heat sink 32. Axial lugs 38 can be formed on a front or end face of the base body 36 in order to ensure a defined point contact on the secondary-side ferrite core 7 of the transmitter device 5.

The components described here can be manufactured economically and can withstand high mechanical loads as a result of centrifugal force and vibrations as well as thermal loads due to internal and external heating. There is also protection against chemical reactions with the surrounding cooling oil.

Furthermore, the following claims are hereby incorporated into the detailed description, whereby each claim may stand on its own as a separate example. While each claim can stand on its own as a separate example, it should be noted that - although a dependent claim may refer to a particular combination with one or more other claims in the claims - other examples also include a combination of the dependent claim with the subject matter of each may include other dependent or independent claims. Such combinations are explicitly suggested here, unless it is stated that a particular combination is not intended. Furthermore, features of a claim should also be included for any other independent claim, even if that claim is not made directly dependent on the independent claim.

Reference symbols

1

Rotor arrangement

2

hollow shaft

3

Rotor lamination package

4

Stator-proof oil lance

5

inductive transmitter device

6

Primary side ferrite core

7

Secondary side ferrite core

8th

External air gap

9

Internal air gap

10

Primary side winding

11

Primary side winding carrier

12

Secondary side winding

13

Secondary winding carrier

14

Rectifier arrangement

15

Rectifier housing

16

rectifier diode

17

Insulation pad

18

contact pin

19

Primary-side winding potting

20

Secondary winding potting

21

insulation

22

Contact pin

23

Circuit board

24

Connection socket

25

Heat sink

26

screws

27

Via

28

Potting compound

29

axial front thermal conductive potting

30

axially rear thermal conductive potting

31

PCB potting

32

Heat sink

33

Pen

34

Insulating element

35

Component carrier

36

Basic body

37

punched grid

38

axial noses

Claims (15)

A rotor arrangement (1) for a separately excited synchronous machine, comprising the rotor arrangement a rotor shaft (2) designed as a hollow shaft for at least one field winding; a transformer (5) arranged within the rotor shaft (2) for the contactless transmission of a current required for rotor field generation to the excitation winding, the transformer (5) having a stator-fixed primary side and a secondary side coupled in a rotationally fixed manner to the rotor shaft; and a rectifier (14) arranged within the rotor shaft (2) and electrically coupled between the secondary side of the transformer (5) and the field winding, the secondary side of the transformer (5) and the rectifier (4) being connected via an axial electrically conductive press-fit connection ( 22) are coupled to each other. The rotor arrangement (1) according to Claim 1 , wherein the rectifier (14) has a carrier (23; 35) for rectifier diodes (16), wherein at least one electrically conductive contact pin (22) of the press-fit connection electrically connects a secondary-side winding (12) of the transformer (5) with a metallized through-hole of the carrier (23; 35). The rotor arrangement (1) according to Claim 2 , wherein the carrier (23; 35) has an electrically conductive lead frame (37) for electrically connecting the secondary side of the transformer (5) to the rectifier diodes (16). The rotor arrangement (1) according to Claim 2 , wherein the carrier has a circuit board (23) as a substrate for the rectifier diodes (16). The rotor arrangement (1) according to Claim 4 , wherein the circuit board (23) is designed as an IMS circuit board and / or has vias (27) in order to transport heat away from the rectifier (14). The rotor arrangement (1) according to one of the Claims 2 until 5 , whereby the rectifier diodes (16) are designed as SMD components or as THT components. The rotor arrangement (1) according to one of the Claims 2 until 6 , wherein the carrier (23; 35) and the rectifier diodes (16) are cast with a casting compound (28; 29; 30). The rotor arrangement (1) according to Claim 7 , wherein the casting compound (28; 29; 30) has a thermal conductivity higher than 2 W/mK. The rotor arrangement (1) according to one of the preceding claims, wherein the rectifier (14) has at least one clamping socket (24) in order to electrically couple the rectifier on the output side to the field winding via at least one radial connecting line. The rotor arrangement (1) according to one of the preceding claims, wherein the rectifier (14) has a heat sink (25; 32) which is formed at an axial end of the rectifier or radially surrounds rectifier diodes (16) of the rectifier. The rotor arrangement (1) according to one of the preceding claims, wherein a primary-side and a secondary-side winding (10; 12) of the transformer (5) are each designed as a flat strip winding. The rotor arrangement (1) according to one of the preceding claims, further comprising a stator-fixed carrier (4) which projects axially into a cavity of the rotor shaft (2) and is mechanically coupled to the primary side of the transformer (4). The rotor arrangement (1) according to one of the preceding claims, wherein the transformer (5) comprises a stator-fixed, primary-side ferrite core (6), in which a primary-side winding (10) of the transformer is inserted, and a rotatable relative to the primary-side ferrite core with the rotor shaft (2) comprises a non-rotatably coupled secondary-side ferrite core (7), in which a secondary-side winding (12) of the transformer is inserted. The rotor arrangement (1) according to one of the preceding claims, wherein the field winding extends axially from an initial region to an end region along the rotor shaft (2) and wherein the transformer (5) and rectifier (14) axially between the initial region and the end region of the field winding is arranged within the rotor shaft (2). The rotor arrangement (1) according to one of the preceding claims, wherein an outer diameter of a housing (21) of the transformer (5) and an outer diameter of a housing of the rectifier (14) are adapted to an inner diameter of the rotor shaft (2).

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