Slim, simple HV terminal for electric motors

Abstract

Stator (1) for an electric machine, comprising a high-voltage terminal (2) with three busbars (13) each having two contact pins (8), a stator carrier (3), a stator winding (4) which sectionally comprises a first group (5) of wires arranged around a first radius (R1) and a second group (6) of wires arranged around a second radius (R2), wherein the wires extend axially from the stator winding (4) starting from an axial end face of the stator carrier (3) and the first radius (R1) is smaller than the second radius (R2), wherein the first group (5) of wires have a first bend (7) spaced axially from the axial end face of the stator carrier (3) such that the distal ends of the first group (5) of wires project radially outwards beyond the second group (6) of wires,and the distal ends of the first group (5) of wires have contact pins (8) which are metallurgically connected to the two contact pins (8) of the interconnection elements of the high-voltage terminal (2).

Description

[0001] The present invention relates to a stator of an electric machine, comprising in particular a stator winding made of an endless mat and a high-voltage terminal, and to an electric machine comprising the stator according to the invention.

[0002] Permanent magnet synchronous machines (PMSMs) are already used in many industrial applications and, with electrification, increasingly in the automotive industry as well. Such a permanent magnet synchronous machine typically has a stator and a permanently excited rotor. The stator includes, among other things, a stator winding, a stator support, a connecting ring, and a terminal for the power electronics.

[0003] Electrical machines with distributed or wave windings typically have a connection point where different conductors of the winding are connected. This connection is also called a bridge and is usually responsible for reversing the direction of current flow. Furthermore, the connection may also include a so-called star point or star phase. At this point, all conductors and currents of the different phases converge according to a star connection. The electrical machine also has a high-voltage terminal. This component is responsible for supplying power to the electrical machine via the power electronics.

[0004] High-voltage terminals with an integrated interconnection area are now known from the prior art. For example, DE 10 2019 111 825 A1 discloses a stator for an electric machine with such a high-voltage terminal. For further prior art regarding high-voltage terminals for electric machines, reference is made to DE 10 2019 103 191 A1, DE 10 2019 121 186 A1, DE 10 2016 222 611 A1, JP 2020 - 167 788 A and WO 2021 / 074 565 A1.

[0005] Although such components are known from the prior art, there remains a desire to optimize them. Therefore, the object of the present invention is to provide a high-voltage terminal that is improved compared to the prior art. In particular, it is to provide a high-voltage terminal that allows integration into the limited installation space of a stator or stator winding in the most compact way possible.

[0006] Furthermore, the object of the present invention is to provide an improved stator winding, an improved stator, and an improved electrical machine compared to the prior art.

[0007] The problem is solved by the measures described in the independent claims. Further advantageous embodiments are listed in the independent claims.

[0008] According to one aspect, a stator for an electric machine has a high-voltage terminal with a connection element, a stator carrier, and a stator winding which sectionally has a first group of wires arranged around a first radius and a second group of wires arranged around a second radius, wherein the wires extend axially out of the stator winding from an axial end face of the stator carrier and the first radius is smaller than the second radius.

[0009] According to the invention, the first group of wires has a first bend spaced axially from the axial end face of the stator support, such that the distal ends of the first group of wires project radially outwards beyond the second group of wires, and the distal ends of the first group of wires have contact pins which are metallurgically connected to contact pins of a switching element of the high-voltage terminal. In particular, the wires are surrounded by an insulating layer, the insulating layer being removed at the distal ends so that the contact pins are formed. The spatial arrangement of the distal ends of the first group of wires projecting radially outwards beyond the second group of wires results in an advantageous reduction of the effects of air gaps and creepage distances.This also advantageously reduces the complexity of the stator, especially the high-voltage terminal, significantly, as elaborate insulation measures can be largely dispensed with.

[0010] According to one embodiment, the first group of wires has a second bend, which is arranged starting from the axial end face of the stator carrier after the first bend, so that the contact pins of the first group are aligned in the axial direction.

[0011] The alignment of the contact pins is particularly advantageous for subsequent thermal joining processes of the stator winding contact pins to the high-voltage terminal contact pins. The second bend is especially advantageously arranged radially outside the second group of wires. Furthermore, it is advantageous if the first and second bends are of the same magnitude but in opposite directions. It is particularly advantageous if a section of the wire located between the first and second bends lies in a plane perpendicular to the axis of rotation.

[0012] According to one embodiment, a wire of the first group of wires has a third bend and a fourth bend between the first bend and the second bend, such that the contact pin of the wire is offset in the circumferential direction. It is particularly advantageous if the third bend and the fourth bend are located in a plane that is arranged perpendicular to the axis of rotation.

[0013] According to one embodiment, the high-voltage terminal has a plastic element and the interconnection element designed as a busbar for connecting the high-voltage terminal to power electronics, wherein two adjacent contact pins of the first group of wires are connected to the contact pins of the interconnection element, and the interconnection element is partially enclosed by the plastic element.

[0014] Advantageously, the plastic element is designed as a potting compound, thus securely fixing the busbar-type connection elements in their spatial position. This simplifies the mounting of the high-voltage terminal to the stator or stator winding.

[0015] According to one embodiment, the contact pins of the interconnection element are oriented in an axial direction and the high-voltage terminal is oriented with a first side of the first plastic element towards the axial end face of the stator carrier.

[0016] According to one embodiment, the stator winding is designed as an endless mat and the wires have a rectangular cross-section.

[0017] According to one embodiment, a third group of wires arranged around a first radius is connected to realize the star phase.

[0018] Particularly advantageous is the material-bonded connection of the contact pins of the third group of wires, especially via a connecting element, which can, for example, be designed as a wire busbar. A particular advantage here is that the connecting element designed as a wire busbar does not require insulation, since other wires of the continuous mat in the immediate vicinity are insulated.

[0019] According to one embodiment, contact pins of wires of the second group are directly connected to each other in pairs by a material-bonded connection to realize the phase shift.

[0020] This makes it particularly advantageous to avoid the need for a further interconnection element by bending individual wires of the second groups towards each other.

[0021] According to one aspect, an electrical machine comprises a stator according to the invention.

[0022] For the purposes of the present invention, the term "endless mat" refers to a stator winding that is typically wound and folded multiple times. In particular, it is a wave winding.

[0023] For the purposes of the present invention, the term "plastic element" refers to a component made of a plastic and / or a plastic-like material. This can be, for example, a plastic film, such as a polyimide film, or an epoxy resin and / or acrylate-based potting compound. Furthermore, the plastic element can also be composed of connectable components made of a plastic commonly used in electrical applications, such as polyphenylene sulfide (PPS), polyphthalamide (PPA), polyetheretherketone (PEEK), and / or mixtures thereof, preferably of one of these materials.

[0024] For the purposes of the present invention, material-bonded connections are understood to be connections achieved by processes in which the joining partners are held together by atomic or molecular forces. These are simultaneously inseparable connections that can only be separated by destroying the bonding agent. Methods include, in particular, gluing, welding, soldering, or vulcanizing.

[0025] The invention and its technical context are explained in more detail below with reference to the figures. It should be noted that the invention is not limited to the embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract aspects of the concepts illustrated in the figures and combine them with other elements and findings from the present description and / or figures. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. Identical reference numerals denote the same objects, so that explanations from other figures may be consulted for further clarification. Terms such as radial, axial, or similar refer to the axis of rotation of the electrical machine, unless a different reference is explicitly used.Furthermore, for the sake of better readability of the figures, only individual or a few identical elements of a reference symbol may be provided.

[0026] It shows Fig. 1. A section of a top view of a stator Fig. 2 a section of a perspective view of the stator Fig. 1.

[0027] Fig. Figure 1 shows a section of a top view of a stator 1 comprising a stator support 3, a stator winding 4, and a high-voltage terminal 2. The perspective is oriented such that an axial end face of the stator support 3 lies in the plane of the image. The stator winding 4 is designed as a wave winding. The high-voltage terminal 2 is arranged radially outside the stator winding 4 on the end face of the stator support 3. The high-voltage terminal comprises a plastic element 12 in which three busbars 13, each with two contact pins 8, are included. The contact pins 8 of the busbars 13 project axially from the plastic element 12. On a radially inward-oriented side of the contact pins 8 of the busbar 13, one contact pin 8 of a wire from the first group 5 of wires is metallurgically bonded. The contact pin 8 of the wire of the first group of wires represents a distal end of the wire and is oriented in an axial direction.The contact pins 8 are arranged radially outwards beyond the second group (6) of wires at a radius R2. Starting from the distal end, a second bend 9 is formed, through which the wire runs radially inwards in a plane perpendicular to the axis of rotation. A first bend 7 then directs the wire axially into the stator carrier 3 as part of the stator winding 4 at a radius R1. The two wires of the first group 5, located on the right in the plane of the image, each have a third bend 10 and a fourth bend 11, which causes the contact pins 8 of the corresponding wires to be offset circumferentially. The other wires of the first group 5 do not have such an offset.

[0028] Fig. Figure 2 shows a section of a perspective view of the stator. Fig.1. A third group 14 of wires arranged around the first radius R1 is connected by means of a rail 15. The second group 6 of wires arranged around the second radius R2 is designed to implement the so-called phase shift. Thus, each wire of the second group 6 is connected to another wire of the second group 6 by means of a material bond. Reference symbol list 1 Stator 2 high-voltage terminals 3 Stator carriers 4 Stator winding 5 first group 6 second group 7 first bend 8 contact pins 9 second bend 10 third bend 11 fourth bend 12 plastic elements 13 Power rail 14 third group 15 rail R1 first radius R2 second radius

Images