Rectifier unit for a rotor device, rotor device and separately excited synchronous machine

Abstract

A rectifier unit (118) for a rotor device (112) is presented, wherein the rectifier unit (118) comprises a first carrier unit (204) for at least partial arrangement in a rotor hollow shaft (200), wherein the first carrier unit (204) has a first circuit board (206) with at least one diode of a rectifier circuit and a first cooling element (208) arranged on the circuit board (206) and facing away from the diode, the first cooling element being designed to dissipate heat to the rotor hollow shaft (200) via a surface of the first cooling element (208), the surface of which is curved, and a second carrier unit (210) for at least partial arrangement in the rotor hollow shaft (200), wherein the second carrier unit (210) has a second circuit board (212) with at least one further diode of the rectifier circuit and a second cooling element (214) arranged on the second circuit board (212) and facing away from the further diode. exhibits that is trained,to dissipate heat via a shell surface of the second cooling element (214) to the rotor hollow shaft (200), wherein the shell surface is curved.

Description

[0001] The present invention relates to a rectifier unit for a rotor device, to a rotor device, to a separately excited synchronous machine, to an electric axle drive and to a motor vehicle.

[0002] Drives are used in many different devices and machines, and therefore in various sectors. For example, in the automotive industry, drives are used for different vehicle functions and to propel a vehicle.

[0003] Against this background, the present invention provides an improved rectifier unit for a rotor device, an improved rotor device for a separately excited synchronous machine, an improved separately excited synchronous machine, an improved electric axle drive, and an improved motor vehicle according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

[0004] The presented approach advantageously creates a way to efficiently utilize available installation space. Furthermore, it allows for the advantageous achievement of high heat dissipation. Multiple functions, such as cooling and supporting an electronic circuit, can be easily implemented and integrated in a space-saving manner. Additionally, a printed circuit board can be scaled not only axially, i.e., lengthwise, but also in other directions, thus avoiding the limitations of the installation space.

[0005] The described approach can advantageously be implemented in connection with a separately excited synchronous machine comprising a stator assembly, also referred to as a stator, and a rotor assembly. The rotor assembly comprises a rotor rotatably mounted relative to the stator, with a hollow rotor shaft on which a rotor winding is mounted. A stator-fixed primary-side transformer assembly with a primary ferrite and a primary coil is inserted into the hollow rotor shaft. The primary-side transformer assembly interacts with a rotor-fixed secondary-side transformer assembly with a secondary ferrite and a secondary coil, which is arranged inside the hollow rotor shaft.

[0006] A rectifier unit for a rotor device of a separately excited synchronous machine is therefore presented, wherein the rectifier unit comprises a first support unit for at least partial installation in a hollow rotor shaft. The first support unit includes a first circuit board with at least one diode of a rectifier circuit for converting an AC excitation voltage of a secondary winding into a DC excitation voltage for a rotor winding, as well as a first cooling element arranged on the circuit board and facing away from the diode, which is designed to dissipate heat to the hollow rotor shaft via a surface of the first cooling element. The surface of the first cooling element is curved.Furthermore, the rectifier unit has a second support unit opposite the first support unit for at least partial placement in the rotor hollow shaft. The second support unit comprises a second circuit board with at least one further diode of the rectifier circuit for converting an AC excitation voltage of a secondary winding into a DC excitation voltage for a rotor winding, and a second cooling element arranged on the second circuit board, facing away from the diode. This cooling element is designed to dissipate heat to the rotor hollow shaft via a curved surface.

[0007] The rectifier unit can be designed as part of a rotor assembly. The rotor assembly can, for example, be referred to simply as a rotor, or be designed as part of one. The separately excited synchronous machine, for which the rotor assembly can advantageously be used, can, for example, be called a motor, which can be used, for instance, in a vehicle. The magnetic field of the rotor assembly can advantageously interact with a stator of the separately excited synchronous machine to drive it. The rectifier unit can, for example, be implemented in a lance-like form, thus saving installation space. By using several carrier units, imbalance in the rotor hollow shaft can advantageously be avoided. The circuit boards can advantageously have conductive traces for contacting the diodes.The circuit boards are connected to the cooling elements, allowing the cooling elements to dissipate heat generated on the boards to the hollow rotor shaft, which can then be used as a heat sink. This advantageously prevents damage caused by overheating. The first diode, and additionally or alternatively the second diode, can be bonded to the circuit boards, for example, by soldering. Advantageously, the support units can be arranged along a main axis of the rectifier unit, and their cooling elements can be implemented for heat dissipation. The cooling elements can advantageously be adapted to the shape of an inner wall of the hollow rotor shaft. For example, the surfaces of the cooling elements can form a section of a circular cylinder. The hollow rotor shaft can rotate about an axis of rotation passing through it.Since the rectifier unit is connected to an outer wall of the rotor hollow shaft, it can advantageously rotate with it. The circuit board can, for example, be an IMS board. The support units can, for example, be made of metal or be designed as printed circuit boards. The rectifier circuit can comprise a total of four diodes, which can be connected according to known rectifier circuits.

[0008] According to one embodiment, the at least one diode of the first carrier unit and the at least one further diode of the second carrier unit can be electrically coupled to each other. For example, an electrical connection bridge between the first diode and the second diode can be realized by means of an electrical conductor or a stamped grid.

[0009] The rectifier unit can include an elastic spacer that can be positioned between the first and second support units. Advantageously, the spacer can be designed as a plastic standoff. For example, spring elements can be integrated into the spacer to compensate for or cushion deformations caused by differing thermal coefficients of the individual components. This advantageously prevents damage.

[0010] Furthermore, the spacer can have at least one electrical conductor between the circuit boards, and additionally or alternatively, the spacer can be electrically insulating. The electrical conductor can, for example, be integrated into the spacer and at least partially surrounded by insulating material.

[0011] According to one embodiment, the first support unit and the second support unit can each have at least one receiving opening for receiving the spacer. For example, the spacer can have pin-like locking tabs that can be inserted into the receiving opening. Advantageously, this prevents the spacer from slipping.

[0012] The rectifier unit can include a secondary-side transformer device with a secondary ferrite core and the secondary winding, wherein the secondary ferrite core can be metallurgically bonded to the hollow rotor shaft and can support the secondary winding. This allows the secondary-side transformer device and the rectifier circuit to form a single unit.

[0013] The carrier units can each have a coupling section for connecting to the secondary-side transmission device of the rotor device. For example, the carrier units can be coupled to the secondary-side transmission device by means of a plug connection. Furthermore, the parts can be bonded together by a material-fit connection.

[0014] Furthermore, a rotor device for a separately excited synchronous machine is presented, wherein the rotor device comprises a hollow rotor shaft having, for example, a rotationally symmetrical cavity, a rectifier unit in a previously mentioned variant, wherein the rectifier unit is arranged in the hollow rotor shaft, and a primary-side transformer device with a primary ferrite and a primary winding surrounding the primary ferrite. The primary-side transformer device is at least partially arranged in the cavity. The secondary ferrite is arranged opposite and rotatably relative to the primary ferrite.

[0015] The rotor assembly can, for example, be simply referred to as a rotor, which can be used, for instance, in motors. The separately excited synchronous machine can advantageously be used in the automotive industry for various vehicle functions. The primary-side transformer assembly can also be referred to as the primary side of an inductive rotary transformer or transformer assembly. Together with the secondary-side transformer assembly of the rectifier unit, the primary-side transformer assembly can form an inductive rotary transformer. During operation of the separately excited synchronous machine, the primary-side transformer assembly does not rotate with the rotor hollow shaft, but can, for example, be fixedly connected to the stator.

[0016] According to one embodiment, the rotor device can have a rotor winding for generating a rotor magnetic field using the excitation DC voltage, wherein the rotor winding can be wound as a coil outside the rotor shaft around a rotor lamination stack. A magnetic field can be generated by the rotor winding when energized. Advantageously, the magnetic field of the rotor winding can interact with a stator of the separately excited synchronous machine to drive it. A voltage is induced in the secondary winding as a result of the electromagnetic field generated by the primary side of the transformer device when energized. The induced alternating current is rectified by the rectifier circuit before it energizes the rotor winding.

[0017] Furthermore, a separately excited synchronous machine for an electric axle drive is presented, wherein the separately excited synchronous machine has a rotor device in a previously mentioned variant and a stator that cooperates with the rotor device to operate the separately excited synchronous machine.

[0018] A separately excited synchronous machine can, for example, be designed as a drive motor for a vehicle. A separately excited synchronous machine can be a rotating electrical machine in which the rotor can rotate synchronously with the rotating magnetic field of the stator. The stator can be designed as a stationary part and the rotor as a rotating part of the separately excited synchronous machine.

[0019] Furthermore, the invention relates to an electric axle drive for an at least partially electrified motor vehicle comprising at least one separately excited synchronous machine in a previously mentioned variant, a transmission device, and a power converter. The electric axle drive is characterized in that the separately excited synchronous machine is configured as described.

[0020] The transmission unit may include a gearbox for reducing the speed of the separately excited synchronous machine as well as a differential.

[0021] Furthermore, a motor vehicle with an electric axle drive and / or a power converter is presented. The motor vehicle is characterized by the fact that the electric axle drive and / or the power converter is designed as described.

[0022] The invention is explained in more detail by way of example with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of an exemplary embodiment of a motor vehicle; Fig. 2 a perspective view of an embodiment of a rotor device; Fig. 3 a perspective sectional view of an embodiment of a rotor device; Fig. 4 a perspective sectional view of an embodiment of a primary-side transmitter device; Fig. 5 a perspective view of an exemplary embodiment of a rectifier unit; Fig. 6 a perspective view of an embodiment of a rotor device; Fig. 7 a perspective view of an embodiment of a primary-side transmitter device; Fig. 8 a schematic exploded view of an embodiment of a rectifier unit; Fig. 9 a schematic sectional view of an embodiment of a rotor device; Fig. 10 a schematic sectional view of an embodiment of a rotor device; Fig. 11 a circuit diagram of an exemplary embodiment of a rectifier circuit of a rotor device; and Fig. 12 a schematic sectional view of an embodiment of a rotor device.

[0023] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0024] Fig. Figure 1 shows a perspective view of an embodiment of a motor vehicle 100, which can be configured, for example, as a passenger car, but can also be configured as a truck. The motor vehicle 100 is also referred to, for example, as a vehicle and has an electric axle drive 102, which in turn includes at least one separately excited synchronous machine 104 (shown here purely schematically), optionally a transmission unit 106, and a power converter 108. The separately excited synchronous machine 104 is also referred to, for example, as a drive unit and is coupled, for example, to the transmission unit 106. The motor vehicle 100 also has a power supply unit 110, which is referred to, for example, as a battery. According to this embodiment, the power converter 108 is connected between the power supply unit 110 and the separately excited synchronous machine 104.

[0025] The separately excited synchronous machine 104 comprises a rotor assembly 112 and a stator 114, which interacts with the rotor assembly 112 to operate the separately excited synchronous machine 104. The stator 114 is also coupled to the converter 108 by means of a three-phase connection 116. The rotor assembly 112 includes a rotatable hollow rotor shaft into which at least a rectifier unit 118 and a stator-fixed primary-side transformer assembly 120, as part of an inductive rotary transformer, are inserted. For example, the rotor assembly 112 has a rotor winding 113 for generating a rotor magnetic field using a DC excitation voltage, the rotor winding 113 being arranged on the hollow rotor shaft.

[0026] According to one embodiment, the rotor device 112 is rotatably mounted relative to the stator 114 and forms, for example, a motor shaft of the separately excited synchronous machine 104.

[0027] Fig. Figure 2 shows a perspective view of an embodiment of a rotor device 112, as it is used, for example, in Fig. The rotor device 112 comprises a hollow rotor shaft 200, which has a rotationally symmetrical cavity 202, a rectifier unit 118 arranged in the hollow rotor shaft 202, and a primary-side transformer device 120 with a primary ferrite and a primary winding surrounding the primary ferrite, wherein the primary-side transformer device 120 is at least partially arranged in the cavity 202. A secondary ferrite of a secondary-side transformer device of the rectifier unit 118 is arranged opposite and rotatably relative to the primary ferrite.

[0028] The rectifier unit 118 comprises a first support unit 204 for at least partial installation in the rotor hollow shaft 202. The first support unit 204 includes a first circuit board 206 with at least one diode of a rectifier circuit for converting an AC excitation voltage of a secondary winding into a DC excitation voltage for a rotor winding, and a first cooling element 208 arranged on the circuit board 206 and facing away from the diode. The cooling element 208 is designed to dissipate heat to the rotor hollow shaft 202 via a surface of the first cooling element 208. The surface of the cooling element is curved and thus adapted to the shape of the at least partially rotationally symmetrical rotor hollow shaft 202. For example, the cooling element 208 has an approximately semicircular cross-section.Furthermore, the rectifier unit 118 has a second support unit 210 opposite the first support unit 204 for at least partial placement in the rotor hollow shaft 202. The second support unit 210 has a second circuit board 212 with at least one further diode of the rectifier circuit for converting an AC excitation voltage of a secondary winding into a DC excitation voltage for a rotor winding. A second cooling element 214, located away from the diode and arranged on the second circuit board 212, is designed to dissipate heat loss. This cooling element is designed to conduct heat to the rotor hollow shaft 200 via a surface of the second cooling element 214. The surface of the second cooling element 214 is curved and thus adapted to the shape of the rotor hollow shaft 200. The cooling elements 208 and 214 can be identically shaped.

[0029] In other words, an inductive exciter, meaning a rotor device 112 designed as a rectifier in a two-board design with an additional element, is described in which the heat sinks are pressed radially outwards against the shaft even without centrifugal force. The additional element functions, for example, as a spacer between the boards 204 and 212. This means an inductive transformer with two horizontal rectifier boards 204 and 212 with heat dissipation to the rotor hollow shaft 200 with a defined inner diameter is described.

[0030] Fig. Figure 3 shows a perspective sectional view of an embodiment of a rotor device 112, which is used, for example, in Fig. This corresponds to the rotor device described in Section 2. This means that the rotor device 112 also comprises the hollow rotor shaft 202, the primary-side transformer device 120, and the rectifier unit 118 with a secondary-side transformer device 300. The primary-side transformer device 120 has a primary ferrite 302 and a primary winding 304 that wraps around the primary ferrite 302, with the primary-side transformer device 300 being at least partially located in the cavity 202. The secondary-side transformer device 300 has, for example, a secondary ferrite 306 and a secondary winding 308, with the secondary ferrite 306 being metallurgically bonded to the hollow rotor shaft 200 and carrying the secondary winding 308. For example, the secondary ferrite 306 is arranged opposite and rotatably relative to the primary ferrite 302.

[0031] According to this embodiment, the secondary-side transformer device 300 is connected to the rectifier unit 118. For this purpose, the carrier units 204, 210 each have a coupling section 310, 312, by which the carrier units 204, 210 are coupled to each other by means of a material connection, a force connection and / or a positive connection, such as by means of a plug connection. As already described in Fig. As described in Figure 2, the two support units 204 and 210 are arranged on opposite sides of the hollow rotor shaft 202 according to this embodiment. The rectifier unit 118 also includes an elastic spacer 314, which is arranged between the first support unit 204 and the second support unit 210. The spacer 314 is used, for example, as a standoff, which may be made of plastic. At least one spring element 316 is integrated into the spacer 314. Optionally, the spacer 314 may have at least one electrical conductor between the circuit boards 206 and 212 and may also be electrically insulating. Additionally or alternatively, the two circuit boards 206 and 212 are electrically coupled to each other by means of a coupling element 317.To couple the spacer 314 with the support units 204, 214, the support units 204, 214 each have at least one and preferably two receiving openings 318, 320, 322, 324 according to this embodiment. Conversely, the spacer 314 according to this embodiment has a corresponding number of pin-like plug-in lugs 326, 328, 330, 332 which are inserted into the receiving openings 318, 320, 322, 324 and thereby enable a positive-locking connection.

[0032] In other words, a rectifier arrangement is described with two opposing, horizontally arranged rectifier boards 204, 212, each of which is connected to a cooling element 208, 214, which can also be called a heat sink, and which is in contact with the rotor hollow shaft 200 as a heat sink.

[0033] The circuit boards 206, 212 and the cooling elements 208, 214 are arranged radially opposite each other inside the hollow rotor shaft 200. The cooling elements 208, 214 each have contact areas, more precisely their outer surfaces, on the inside of the hollow rotor shaft 200, through which they transfer the heat loss from the electronics. They can also each have at least one, but also several, oil guide contours on their outer surface. As the rotor rotates, the circuit boards 206, 212 and the cooling elements 208, 214 are pressed against the inside of the hollow rotor shaft 200 by centrifugal force.

[0034] To ensure a defined contact even when stationary or at low speeds, an additional contact force is necessary. For this purpose, an elastic element, described here as a spacer 314, is arranged in the radial space between the circuit boards 206 and 212. It is particularly advantageous if this elastic element, or rather the elasticity, is incorporated into the spacer 314, which is made of plastic, for example. The spacer 314 is arranged between the circuit boards 206 and 212. The spacer 314 is also used, for example, to accommodate electrical conductors and insulate them from environmental influences, thus providing electrical connections between the two circuit boards.

[0035] Fig. Figure 4 shows a perspective sectional view of an embodiment of a primary-side transmitter device 120, as used, for example, in at least one of the Fig. 1 to 3 described or at least mentioned. A secondary-side transformer device 300 is also shown, which is, for example, designed as part of the rectifier unit. The primary-side transformer device 120 and the secondary-side transformer device 300 can, for example, together form a transformer for the rotor device. While the primary-side transformer device 120 is fixed to the stator, the secondary-side transformer device 300 is mounted on the rotor side and is therefore rotatable about a main axis 400.

[0036] As previously described, the primary-side transformer 120 comprises the primary ferrite 302 and the primary winding 304. The secondary-side transformer 300 correspondingly comprises the secondary ferrite 306 and the secondary winding 308. On a side 402 facing the carrier units (not shown here), the secondary-side transformer 300 has at least one connecting element 404, 406 for each carrier unit. The connecting elements 404, 406 do not serve for current transmission, but rather for the mechanical connection between an intermediate element coupled to the secondary-side transformer 300 and the carrier unit. For example, the connecting elements 404, 406 are designed as fastening or guide bolts.

[0037] According to this embodiment, the primary-side transformer device 120 has a base body 408 with a receiving area 410 around which the primary ferrite 302 is arranged. The primary winding 304, which is also referred to, for example, as the primary coil, winds around a surface of the primary ferrite 302.

[0038] Fig. Figure 5 shows a perspective sectional view of an embodiment of a rectifier unit 118, as used, for example, in at least one of the Fig. 1 to 3 described or at least mentioned. Here too, the rectifier unit 118 features the spacer 314, as is the case, for example, in Fig. 3 was described.

[0039] Fig. Figure 6 shows a perspective view of an embodiment of a rotor device 112, which is used, for example, in at least one of the Fig. The rotor device 112 corresponds to the rotor device described in sections 1 to 2. However, in order to depict the rectifier unit 118, the rotor device 112 is shown without the hollow rotor shaft in this embodiment, which is shown accordingly. Fig. 2 would surround the rectifier unit 118.

[0040] According to this embodiment, the outer surfaces 600, 602 of the cooling elements 208, 214 are shown, which, in their installed state, are connected to the hollow rotor shaft for heat dissipation. The curved shape of the cooling elements 208, 214 is also shown. A circuit board 206, 212 is arranged on each of the flat sides of the curved cooling elements 208, 214, each of which in turn has at least one and, in particular, two diodes 604, 606. For example, the at least one diode 604 of the first carrier unit 204 and the at least one further diode 606 of the second carrier unit 210 are electrically coupled to each other.

[0041] In this embodiment as well, the spacer 314 is arranged between the two carrier units 204, 210. The spacer 314 has at least one laterally arranged recess 608, 610 for each carrier unit 204, 210, in which one of the diodes 604, 606 is arranged.

[0042] Fig. Figure 7 shows a perspective view of an embodiment of a primary-side transmitter device 120 and a secondary-side transmitter device 300, as used, for example, in Fig. As already described in section 4. In this embodiment, the only difference is the illustration, since the transformer devices 120, 300 are not shown in section. Furthermore, two coil ends 700, 702 of the secondary winding are shown, each of which can be coupled to a circuit board.

[0043] Fig. Figure 8 shows a schematic exploded view of an embodiment of a rectifier unit 118, which is used, for example, in at least one of the Fig. The rectifier unit described or at least mentioned in sections 1 to 7 corresponds to or resembles the rectifier unit. Due to the perspective of the exploded view, the units shown in Fig. The diagram shows the diodes 604 and 606 described in Figure 6, as well as two further diodes 800 and 802 of the rectifier circuit. This means that circuit board 206 has diodes 604 and 800, and circuit board 212 has diodes 606 and 802. Diodes 604, 800, 606, and 802 are implemented here as rectifier diodes of the rectifier unit 118. Additionally, the rectifier unit 118 has a plurality of auxiliary diodes 804 and 806 on each of the circuit boards 206 and 212, which are implemented, for example, as transient voltage suppression (TVS) diodes.

[0044] The two circuit boards 206, 212 can be electrically coupled to each other, for example, by means of the coupling element 317. The coupling element 317 is arranged on a first half 808 of the rectifier unit 118 and is implemented, for example, in a Z-shape. On a second half 810 of the rectifier unit 118, the unit has, according to this embodiment, at least one and, in particular, two connecting elements 812. The connecting elements 812 can also be connected to the two circuit boards 206, 212 and can, for example, be coupled to coil terminals of the secondary winding. The spacer 314 is also arranged between the two circuit boards 206, 212 and optionally has two plastic bodies 814, 816, which are arranged parallel to each other, as well as two connecting pieces 818, 820, also arranged parallel to each other, which are designed like pins and, according to this embodiment, connect the Fig. Shape the 3 described spring elements and the plug-in tabs.

[0045] Fig. Figure 9 shows a schematic sectional view of an embodiment of a rotor device 112, which is used, for example, in at least one of the Fig. This corresponds to the rotor device described or mentioned in Figures 1 to 8. It is shown that the rectifier unit 118 is arranged in the hollow rotor shaft 200. Here too, the spacer 314 is arranged between the first support unit 204 and the second support unit 210, and this spacer in turn has at least one spring element 316. The spring element 316 is designed to press the spacer 314 against the support units 204 and 210, so that these are in turn pressed with their outer surfaces 600 and 602 against an inner surface of the hollow rotor shaft 200.

[0046] In addition, according to this embodiment, the coupling element 317 is shown, which is designed to electrically couple the first circuit board 206 and the second circuit board 212 to each other.

[0047] Fig. Figure 10 shows a schematic sectional view of an embodiment of a rotor device 112, which is, for example, the one described in one of the Fig. The rotor device described or mentioned in points 1 to 9 corresponds in particular to the one described in Fig. 3 described rotor device. According to this embodiment, the rotor device 112 is shown as a pure sectional view and thus not in perspective.

[0048] Fig. Figure 11 shows a circuit diagram of an exemplary embodiment of a rectifier circuit 1100 of a rotor device, such as is used, for example, in at least one of the Fig. 1 to 10 described or mentioned. According to this embodiment, four diodes D1, D2, D3 and D4 are shown, wherein diodes D1 and D2 are described in Fig. The 8 described diodes 604, 800 on the first board correspond to diodes D3 and D4 to diodes 606, 802 on the second board.

[0049] The rectifier circuit 1100 enables the conversion of an alternating voltage Ue, for example provided by the secondary winding, into a direct voltage Ua, for example to be applied to the rotor winding. For example, the anode of diode D1 and the cathode of diode D2 are connected to a first terminal of the secondary coil, the anode of diode D3 and the cathode of diode D4 to a second terminal of the secondary coil, and the cathodes of diodes D1 and D3 to a first terminal of the rotor coil and the anodes of diodes D2 and D4 to a second terminal of the rotor coil.

[0050] The shown design of the rectifier circuit 1100 is chosen as an example and can be replaced by other suitable and known rectification circuits.

[0051] Fig. Figure 12 shows a schematic sectional view of an embodiment of a rotor device 112, as used, for example, in at least one of the Fig. 1 to 10 described or mentioned. More precisely, this embodiment shows a circuit of diodes 604, 800, 606, 802. The circuit of diodes 604, 800, 606, 802 can be described in Fig. The circuit shown in section 11 corresponds to this.

[0052] Diodes 604, 800, 606, and 802 are connected to the coil ends 700 and 702 of the secondary winding, and to coil ends 1200 and 1202 of the rotor winding, respectively. More precisely, the first coil end 700 of the secondary winding is connected to a first electrical line 1204 that connects diodes 604 and 800, and the second coil end 702 of the secondary winding is connected to a second electrical line 1206 that connects diodes 606 and 802. The first coil end 1200 of the rotor winding is connected to a third electrical line 1208 that connects diode 604 and diode 606, and the second coil end 1202 of the rotor winding is connected to a fourth electrical line 1210 that connects diodes 800 and 802.

[0053] Additionally, circuit boards 206 and 212 each have a plurality of auxiliary diodes 804 and 806 connected in series. For example, auxiliary diodes 804 are connected to the third electrical line 1208. The other auxiliary diodes 806, on the other hand, are connected to the fourth electrical line 1210.

[0054] Alternatively, the additional diodes 804 can be coupled to the first electrical line 1204 and the further additional diodes 806 to the second electrical line 1206.

[0055] According to one embodiment, the additional diodes 804 are connected in series between the first electrical line 1204 or the third electrical line 1208 and a first solder point 1221, and the further additional diodes 806 are connected in series between the second electrical line 1206 or the fourth electrical line 1210 and a second solder point 1222. According to one embodiment, the solder points 1221 and 1222 are connected via a coupling element, such as that found, for example, in Fig. 3 is shown as coupling element 317, connected to each other, so that all diodes 804, 806 are connected in series with each other and in parallel to the rotor winding. Reference sign 100 motor vehicles 102 electric axle drive 104 separately excited synchronous machine 106 Gearbox unit 108 power converters 110 Energy supply facility 112 Rotor device 113 Rotor winding 114 Stator 116 Three-phase line 118 Rectifier unit 120 Primary-side transducer device 200 hollow rotor shaft 202 cavity 204 first carrier unit 206 first circuit board 208 first cooling element 210 second carrier unit 212 second circuit board 214 second cooling element 300 Secondary-side transmitter device 302 Primary Ferrite 304 Primary winding 306 Secondary Ferrite 308 Secondary winding 310 coupling section 312 further coupling section 314 spacer 316 Spring element 317 Coupling element 318 Intake opening 320 aperture 322 Intake opening 324 Inlet 326 Plug nose 328 Plug nose 330 Plug nose 332 Plug nose 400 Main extension axis Page 402 404 Connecting element 406 additional connecting element 408 Basic body 410 recording area 600 first lateral surface 602 second lateral surface 604 Diode 606 Diode 608 In-depth study 610 In-depth study 700 first coil end of the secondary winding 702 second coil end of the secondary winding 800 diode 802 Diode 804 Plural of auxiliary diodes 806 Plural of auxiliary diodes 808 first half 810 second half 812 Connecting element 814 plastic bodies 816 plastic bodies 818 Connecting piece 820 Connecting piece 1100 rectifier circuit 1200 first coil end of the rotor winding 1202 second coil end of the rotor winding 1204 first electrical line 1206 second electrical line 1208 third electrical line 1210 fourth electrical line 1221 first solder point 1222 second solder point

Claims

[1] Rectifier unit (118) for a rotor device (112) for a separately excited synchronous machine (104), wherein the rectifier unit (118) has the following features: a first support unit (204) for at least partial arrangement in a rotor hollow shaft (200), wherein the first support unit (204) comprises a first circuit board (206) with at least one diode (604) of a rectifier circuit (1100) for converting an excitation AC voltage of a secondary winding (308) into an excitation DC voltage for a rotor winding (113), and a first cooling element (208) arranged on the circuit board (206) and facing away from the diode (604), which is configured to dissipate heat to the rotor hollow shaft (200) via a surface (600) of the first cooling element (208), wherein the surface (600) is curved; and a second support unit (210) opposite the first support unit (204) for at least partial arrangement in the rotor hollow shaft (200), wherein the second support unit (210) has a second circuit board (212) with at least one further diode (606) of the rectifier circuit (1100) for converting an excitation AC voltage of the secondary winding (308) into an excitation DC voltage for the rotor winding (113), and a second cooling element (214) arranged on the second circuit board (212) facing away from the further diode (606), which is designed to dissipate heat to the rotor hollow shaft (200) via a surface (602) of the second cooling element (214), wherein the surface (602) is curved. [2] Rectifier unit (118) according to claim 1, wherein the at least one diode (604) of the first carrier unit (204) and the at least one further diode (606) of the second carrier unit (210) are electrically coupled to each other. [3] Rectifier unit (118) according to one of the preceding claims, comprising an elastic spacer (314) arranged between the first support unit (204) and the second support unit (210). [4] Rectifier unit (118) according to claim 3, wherein the spacer (314) has at least one electrical conductor between the circuit boards (206, 212) and / or wherein the spacer (314) is electrically insulating. [5] Rectifier unit (118) according to one of claims 3 to 4, wherein the first carrier unit (204) and the second carrier unit (210) each have at least one receiving opening (318, 320, 322, 324) for receiving the spacer (314). [6] Rectifier unit (118) according to one of the preceding claims, comprising a secondary-side transformer device (300) with a secondary ferrite (306) and the secondary winding (308), wherein the secondary ferrite (306) is metallurgically connected to the rotor hollow shaft (200) and carries the secondary winding (308). [7] Rectifier unit (118) according to claim 6, wherein the carrier units (204, 210) each have a coupling section (310, 312) for coupling with the secondary-side transformer device (300) of the rotor device (112). [8] Rotor device (112) for a separately excited synchronous machine (104), wherein the rotor device (112) has the following features: a rotor hollow shaft (200) which has a cavity (202); a rectifier unit (118) according to claim 6, wherein the rectifier unit (118) is arranged in the rotor hollow shaft (200); and a primary-side transformer device (120) with a primary ferrite (302) and a primary winding (304) wrapping the primary ferrite (302), wherein the primary-side transformer device (120) is at least partially arranged in the cavity (202), wherein the secondary ferrite (306) is arranged opposite and rotatably relative to the primary ferrite (302). [9] Rotor device (112) according to claim 8, comprising a rotor winding (113) for generating a rotor magnetic field using the excitation DC voltage, wherein the rotor winding (113) is wound around the rotor hollow shaft (200). [10] Externally excited synchronous machine (104) for an electric axle drive (102), wherein the externally excited synchronous machine (104) has the following features: a rotor device (112) according to one of the preceding claims; and a stator (114) which cooperates with the rotor device (112) to operate the separately excited synchronous machine (104). [11] Electric axle drive (102) for an at least partially electrified motor vehicle (100) comprising at least one separately excited synchronous machine (104) according to claim 12, a transmission device (106) and a power converter (108). [12] Motor vehicle (100), in particular at least partially electrified vehicle (100), comprising an electric axle drive (102) according to claim 11 and / or a separately excited synchronous machine (104) according to claim 11 and / or a rotor device (112) according to any one of claims 8 to 9.

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