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DE-102024004617-A1 - Electrical drive arrangement

DE102024004617A1DE 102024004617 A1DE102024004617 A1DE 102024004617A1DE-102024004617-A1

Abstract

Electric drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) with a rotor shaft (3) and at least one electrically conductive guide element (7), wherein the rotor shaft (3) and the guide element (7) are arranged nested within each other, wherein at least one circumferentially closed damping element (11) encompassing at least the guide element (7) and/or the rotor shaft (3) is designed to dampen disturbance currents generated during operation of the electric drive arrangement (1), in particular bearing currents, by means of a voltage induced in the damping element (11) by the disturbance currents and/or by means of an electrical resistance of the damping element (11).

Inventors

  • Hans-Georg Kneidinger
  • Maximilian Schmitt
  • Niklas Hock
  • Michael Griesbach

Assignees

  • ZF FRIEDRICHSHAFEN AG

Dates

Publication Date
20260513
Application Date
20240918

Claims (11)

  1. Electric drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) with a rotor shaft (3) and at least one electrically conductive guide element (7), wherein the guide element (7) is arranged inside the rotor shaft (3), characterized by at least one circumferentially closed damping element (11) encompassing at least the guide element (7) and/or the rotor shaft (3), which is designed to dampen disturbance currents generated during operation of the electric drive arrangement (1), in particular bearing currents, by means of a voltage induced in the damping element (11) by the disturbance currents and/or by means of an electrical resistance of the damping element (11).
  2. Electrical drive arrangement (1) according to Claim 1 , characterized in that the at least one damping element (11) is arranged on the rotor shaft (3) on a drive side of the laminated core (12) of a rotor of the electric machine (2) and/or the at least one damping element (11) is arranged on the rotor shaft (3) on an output side of the laminated core (12) of the rotor.
  3. Electrical drive arrangement (1) according to Claim 1 or 2 , characterized in that the at least one damping element (11) is arranged on the guide element (7) on a drive side of a rotor of the electric machine (2) and/or the at least one damping element (11) is arranged on the guide element (7) on an output side of the rotor.
  4. Electrical drive arrangement (1) according to one of the preceding claims, characterized in that the at least one damping element (11) is designed to dampen circular bearing currents resistively and/or inductively.
  5. Electrical drive arrangement (1) according to one of the preceding claims, characterized in that the at least one damping element (11) is designed as a ring core.
  6. Electric drive arrangement (1) according to one of the preceding claims, characterized in that the at least one damping element (11) is arranged on the rotor shaft (3) and/or the guide element (7) in a rotationally fixed manner or is arranged in a stationary position.
  7. Electric drive arrangement (1) according to one of the preceding claims, characterized in that the guide element (7) is designed as a shaft, in particular as an output shaft, or as a housing-fixed element, in particular as an earthing or cooling line.
  8. Electric drive arrangement (1) according to one of the preceding claims, characterized in that the at least one damping element (11) is designed to dampen circular bearing currents depending on at least one shielding of the guide element (7).
  9. Electric drive arrangement (1) according to one of the preceding claims, characterized in that the electric drive arrangement (1) has at least one ceramic bearing, in particular for supporting the rotor shaft (3) and/or the guide element (7), and/or that the electric drive arrangement (1) has at least one filter element.
  10. Motor vehicle comprising an electric drive arrangement (1) according to one of the preceding claims.
  11. Method for reducing bearing currents in an electric drive arrangement (1), in particular for a motor vehicle, comprising an electric machine (2) with a rotor shaft (3) and at least one electrically conductive guide element (7), wherein the guide element (7) is arranged inside the rotor shaft (3), characterized in that disturbance currents generated during operation of the electric drive arrangement (1) are reduced by means of at least one circumferentially closed damping element (11) encompassing at least the guide element (7) and/or the rotor shaft (3). in particular bearing currents, by means of a voltage induced by the disturbance currents in the damping element (11) and/or by means of an electrical resistance of the damping element (11).

Description

The invention relates to an electric drive arrangement, in particular for a motor vehicle, comprising an electric machine with a rotor shaft and at least one electrically conductive guide element, wherein the rotor shaft and guide element are arranged nested within each other. Electric drive arrangements, particularly for motor vehicles, comprising an electric machine with a rotor shaft and at least one electrically conductive guide element, wherein the rotor shaft and guide element are nested within each other, are generally known from the prior art. It is further known from the prior art that common-mode currents or common-mode voltages arise as high-frequency excitation due to the switching operation of an inverter in the electric drive arrangement. These cause interference currents in the electric drive arrangement, which can manifest themselves as bearing currents and electromagnetic radiation and can therefore negatively affect the drive arrangement. One form of such bearing currents, particularly when using new inverter technologies (SiC, GaN) in conjunction with comparatively high parasitic capacitances, especially in larger electric machines and/or hairpin windings, is circular bearing currents. These bearing currents can damage rolling bearings in the electric drive assembly, which, for example, support the rotor shaft and/or the guide element, potentially leading to mechanical impairment or noticeable noise. To avoid such bearing currents, it is known to minimize the previously described common-mode currents, thereby also reducing the circular magnetic field that induces the circular bearing currents in the drive assembly. Alternatively, it is known to interrupt the current path for the bearing currents as much as possible, for example, by applying a non-conductive coating to various areas of the electrical drive assembly or by using ceramic bearings to prevent current flow through the bearings. However, this can, for example, shift the problem, as higher static voltages can develop across the bearing due to the interruption. Furthermore, even if a specific current path is interrupted, for example, via a bearing, another current path can form, so that the current path only shifts geographically but still develops. The invention is based on the objective of providing an improved electrical drive arrangement in which the occurrence of circular bearing currents is better prevented. The problem is solved by an electric drive arrangement having the features of claim 1. Advantageous embodiments are the subject of the dependent claims. As described, the invention relates to an electric drive arrangement, specifically for a motor vehicle. The electric drive arrangement comprises an electric machine. The electric machine is designed, in particular, as a traction drive for the motor vehicle. This means that the electric machine is designed to generate torque for propelling the motor vehicle. The electric machine has a rotor shaft and at least one electrically conductive guide element, which are arranged nested within one another. This means, in particular, that the electrically conductive guide element is arranged within a space defined by the rotor shaft. For example, the rotor shaft can be designed as a hollow shaft, and the electrically conductive guide element can pass through the cavity or at least partially engage within the cavity. Alternatively, the electrically conductive guide element can also define a cavity in which the rotor shaft is arranged, at least partially. In particular, the guide element and the rotor shaft are arranged coaxially. The invention is based on the finding that the electric drive arrangement comprises at least one circumferentially closed damping element, encompassing at least the guide element and/or the rotor shaft, which is designed to dampen disturbance currents generated during operation of the electric drive arrangement, in particular bearing currents, by means of a voltage induced in the damping element by the disturbance currents and/or by an electrical resistance of the damping element. In other words, a damping element is arranged at least around the guide element and/or the rotor shaft. The damping element is circumferentially closed, for example as a ring or band, which is arranged on the guide element and/or on the rotor shaft or is arranged in a closed form around it. The damping element represents an electrical impedance and is electrically insulated from the guide element or the rotor shaft on which it is arranged. For example, if a circular magnetic field occurs, formed due to common-mode currents, a damping magnetic field is generated in the damping element by circular bearing currents. The damping magnetic field induces a voltage across the guide element or the rotor shaft, which Following Lenz's law, the damping element counteracts the generation of circular bearing currents and dampens them accordingly. Alternatively, a current can be induced in the dam