Electric machine, fuel cell system and element for electrical insulation

Abstract

The invention relates to an electric machine (16) having a stator (28) which has a stator base body (306) which is preferably configured in a cylindrical manner, wherein the stator (28) has at least one winding head (70), wherein the stator base body is provided with electric winding wires (8a, 8b, 8c), wherein the winding wires at least partially protrude from the stator base body on at least one end side of the stator base body (306) and here transition into a compact wire region, in particular a winding ring (73), of the winding head (70), wherein at least one element (601, 611) for electrical insulation is arranged between the stator base body (306) and the compact wire region (73).

Description

Technical Field

[0001] This invention relates to an electric motor, a fuel cell system, and a component for electrical insulation. Background Technology

[0002] An electric motor is known in DE 10 2018 210 162 A1, the motor being configured as a gas delivery device in the form of an air compressor for a fuel cell system. The air compressor has a compressor wheel connected to a rotor, wherein the rotor is driven by an electric motor. The electric motor has a stator surrounding the rotor, wherein the stator has a stator section with stator windings.

[0003] High-speed electric motors are now used in various fields. In particular, they are used in electric compressors, whose speed range can significantly exceed 50,000 revolutions per minute (U / min) to well over 100,000 U / min. These motors are typically controlled by large pulse width modulation frequencies. To compensate for the skin effect, a large number of parallel conductor windings are typically used per phase. These parallel conductor windings are embedded in laminations. The small number of poles determined by the high speed in the motor design results in a large wiring span of the copper windings in the winding heads. The resulting winding heads are typically designed to be very large. Summary of the Invention

[0004] According to the present invention, an electric motor having a stator having a stator base preferably cylindrically constructed, wherein the stator has at least one winding head, wherein the stator base is provided with electrical winding conductors, wherein the winding conductors extend at least partially from the stator base at at least one end side of the stator base and transition therein into a compact conductor region of the winding head, particularly a winding loop, characterized in that at least one element for electrical insulation is arranged between the stator base and the compact conductor region.

[0005] Compared with the prior art, the motor according to the present invention has the advantage that a safe minimum spacing can be maintained between the compact winding region of the guiding potential outside the stator base and, in particular, the stator base.

[0006] The proposed motor can be advantageously expanded and improved through further enumerated measures.

[0007] Advantageously, the element for electrical insulation is constructed such that it prevents partial discharge in the compact conductor region or between the winding head and the stator substrate.

[0008] Advantageously, the element used for electrical insulation is constructed in a ring shape.

[0009] Advantageously, the element used for electrical insulation is made of a non-conductive material.

[0010] Advantageously, the element used for electrical insulation is an insulating disc.

[0011] Advantageously, the insulating disk has a central circular hole.

[0012] Advantageously, the central circular aperture extends radially outward through a free space devoid of material, wherein the shape and position of the free space are adapted to the predetermined positions of the winding conductors extending from the stator matrix.

[0013] Advantageously, the free space is surrounded by flanges at the edges.

[0014] Advantageously, the flange includes radially inwardly pointing ribs.

[0015] Advantageously, the ribs terminate radially inward at a predetermined equal interval relative to the center of the insulating disk, thereby ensuring that the circular hole at the center is free of material.

[0016] Advantageously, the element for electrical insulation at least covers the stator base on its outer periphery or extends beyond the stator base.

[0017] Advantageously, the motor has a rotor that is supported such that it is at least partially surrounded by the stator.

[0018] Advantageously, the motor is configured as an electrically driven air compressor.

[0019] Advantageously, the electrically driven air compressor is configured to supply air or oxygen to the fuel cell stack in the cathode system of the fuel cell stack.

[0020] According to the present invention, a fuel cell system for generating electrical energy from hydrogen and oxygen is proposed, having the motor for supplying air or oxygen to the fuel cell stack of the fuel cell system.

[0021] According to the present invention, an element for electrical insulation is proposed for electrically insulating between the compact conductor region of the motor and the stator base of such motor. Attached Figure Description

[0022] Embodiments of the invention are illustrated in the accompanying drawings and are further explained in the following description. The accompanying drawings illustrate... Figure 1 Fuel cell system Figure 2 :stator, Figure 3 The internal structure of the stator and Figure 4 An insulating disc with a flange. Detailed Implementation

[0023] Figure 1 A schematic diagram of a fuel cell system 1, for example, for a motor vehicle, is shown, having a gas delivery device implemented as an air compressor. The fuel cell system has at least one fuel cell stack 10, which is supplied with fuel, such as hydrogen, via an anode system 12 and with an oxidant, particularly air, via a cathode system 14. The cathode system 14 has a gas delivery device 16 in the form of an air compressor, by which air is supplied to the fuel cell stack in the amount and pressure required for the corresponding operating state. The air compressor 16 has a multi-part housing 18 in which an electric motor 20 is arranged as a driver, by which a shaft 22 is rotatably driven about its longitudinal axis 23, the shaft being connected to at least one compressor wheel 24. The shaft 22 is connected to a rotor 26 of the electric motor 20, or the rotor 26 is part of the shaft 22. The electric motor 20 further has a stator 28 surrounding the rotor 26.

[0024] The stator 28 is arranged in the housing 18. The stator 28 has a stator base, which may be composed of a plurality of stator laminations assembled into a group (“laminate group”) or a plurality of such groups.

[0025] Figure 2The stator 28 is shown in a perspective view from the outside. In the current example, a stator with only one winding head 70 is shown. However, it is also possible to have one winding head on each of the two end sides. The winding head 70 has a winding ring 73 with an annular structure in the current example, which is composed of closely spaced winding wires that extend from a groove constructed on the inner side of the stator base 306 as cable bundles 71 of the winding head 70 at the end side and transition into the winding ring 73 of the winding head 70 at a distance from the stator base. The stator base is composed of one or more lamination groups 501, which are themselves composed of a plurality of stator laminations 401. In this configuration, an element 601 for electrical insulation is arranged on the end face of the stator base between the stator laminations and the winding ring 73. This element has at least one opening (not shown in detail) in its internal region such that the winding conductors extend from the stator base as a cable bundle 71 within the stator base and can converge in the winding ring 73 as a geometrical configuration. Element 601 ensures an electrically insulating distance between the winding ring and the end face of the lamination assembly or the stator base. In the current example, the outer diameter of the winding ring is smaller than the outer diameter of the stator base. In an alternative embodiment, the outer diameter of the winding ring is larger than the outer diameter of the stator base.

[0026] The stator winding conductors, simply referred to as stator windings, extend within the stator base along the longitudinal axis 23 between two opposing ends of the stator base, in a manner not further shown. The stator windings extend longitudinally out of the stator base at their ends and, in this case, are constructed at the end sides, preferably at both end sides, as so-called winding loops 73. Within the regions of the winding loops 73, each stator winding extends partially laterally relative to the longitudinal axis 23 of the stator 28, for example, also in its circumferential direction.

[0027] exist Figure 2 The rotor 26, not shown in the figure, is in this case, as in Figure 1 As shown, the rotor 26 is arranged within the stator 28 with a small radial spacing relative to the stator windings, wherein preferably, an electrical insulation device is provided between the stator windings and the rotor 26 in a manner not shown in further detail.

[0028] Because the available length of the stator in the longitudinal axis 23 is limited, determined by the maximum motor shaft length resulting from the maximum possible spacing of the necessary shaft bearings due to installation space constraints, the winding heads or winding rings are very compact. Therefore, the spacing between the underside of the winding rings and the stator base or lamination assembly is minimal. Because manufacturing defects may occur in the copper conductors within the winding rings, it is essential to ensure a minimum spacing between the winding rings that guide the potential and the lamination assembly, which is typically grounded and thus electrically connected to the housing, to comply with the standard air gaps and creepage distances for electrical insulation. Due to the springback behavior of the conductors after forming and the goal of minimizing installation space, elements 601 for electrical insulation are provided at the stator base ends to ensure said electrical insulation.

[0029] Figure 3 A schematic top view of a portion of stator 28, namely stator base 306, is shown, comprising one or more groups of overlapping, stacked plates (not further shown) with circular outer edges. A partial top view of such a stator base is also shown, in which winding conductors are laid in a recess of the stator. Stator base 306 is visible on the right, wherein it is typically cylindrical, having an outer wall 308 and an inner wall 310. Individual recesses 2a, 2b, 2c, 2d and protrusions 312a, 312b, 312c are alternately seen in enlarged portion A on the left. Protrusions 312a, 312b, 312c have a columnar shape in the illustrated embodiment, which evolves into columnar legs on the inner wall 310 of stator 28, such that protrusions 312a, 312b, 312c have laterally projecting sections. Grooves 2a, 2b, 2c, and 2d are constructed in a teardrop shape and respectively lead into groove openings 6a, 6b, 6c, and 6d. Grooves 2a, 2b, 2c, and 2d are also covered with first insulating paper 100, which is shown here exemplarily with respect to groove 2b. Furthermore, grooves 2a, 2b, 2c, and 2d are traversed by wires 8a, 8b, and 8c, which are shown here only with respect to groove 2b for clarity, and only wires 8a, 8b, and 8c are identified. Additionally, second insulating paper 111 is inserted into grooves 2a, 2b, 2c, and 2d via path C, which is also shown here exemplarily with respect to groove 2b. As can be seen in enlarged section B, the second insulating paper 111 includes a backing portion 13 and a first leg 260 and a second leg 280, which abut against the first insulating paper 100 after insertion into groove 2d.

[0030] Figure 4 An element 601 for electrical insulation is shown in the form of an insulating disk 611 having a flange 613. This insulating disk replicates a design similar to... Figure 3 The stator base 306 has a defined outline and is made of a non-conductive material. In this case, the insulating disk has a circular outer edge 615, on which an annular, enclosed region 617 is joined inwardly. The region terminates inwardly with a flange 613, which surrounds a central circular aperture 619, providing the necessary space for the rotor 26 of the electric air compressor to be installed in accordance with specified operation. The flange 613 is formed on one side of the disk, i.e., on... Figure 4 The raised portion arranged on the side is shown in the figure. The raised portion can be solid or deformed as an edge of the insulating disk material, forming a corresponding shape on the side of the disk. Here, in order to replicate the contour of the stator base, especially the end sides, the flange is constructed with ribs 621 pointing inward toward the annular region 617, such that the ribs precisely surround the end sides of the grooves 2a, 2b, 2c, and 2d, according to... Figure 3 The winding conductors 8a, 8b, and 8c can protrude from the end side to transition into the winding loop 73 as cable bundle 71. The material-free region 619 is thus supplemented radially outward with free space 623, which is located at the height of the groove and thus keeps the groove open at the end side.

[0031] By allowing necessary tolerances, especially even when the insulating disc has no flange, a possible gap is always maintained between the insulating paper 100, 111 of the lamination assembly / stator substrate 306 or the groove of the lamination assembly and the insulating disc or the element for electrical insulation. This allows for the theoretical creepage distance from this non-insulated location to the copper conductor of the winding head. The flange 613 is particularly used to ensure electrical insulation relative to the winding head in the area of ​​the groove or insulating paper on the end side of the stator substrate. This ensures sufficient spacing between the winding head and the lamination assembly. Furthermore, surface insulation of the lamination assembly relative to the winding head is provided. Non-compliant air gaps and creepage distances in the transition area from the lamination assembly / grooved insulation / element for electrical insulation to the winding head above it are avoided by the insulating disc and the flange of the insulating disc. The necessary insulation spacing is automatically adjusted by the predetermined height of the flange. The flange of the insulating disc simplifies the possible manufacturing process for electric air compressors because the necessary spacing between the winding head and the lamination assembly is reliably adjusted by the components, and no additional "spacer tool" is required when pressing the winding head.

Claims

1. An electric motor (16) having a stator (28), said stator having a stator base (306), said stator base preferably being cylindrically constructed, wherein, The stator (28) has at least one winding head (70), wherein the stator base is provided with electrical winding conductors (8a, 8b, 8c), wherein the winding conductors extend at least partially from the stator base (306) at at least one end side and transition here into the compact conductor region of the winding head (70), in particular the winding loop (73), characterized in that at least one element (601, 611) for electrical insulation is arranged between the stator base (306) and the compact conductor region (73).

2. The motor according to claim 1, characterized in that, The electrical insulation elements (601, 611) are configured such that they prevent partial discharge between the compact conductor region (73) or the winding head (70) and the stator base (306).

3. The motor according to any one of the preceding claims, characterized in that, The components (601, 611) used for electrical insulation are constructed in annular (617) shape.

4. The motor according to any one of the preceding claims, characterized in that, The components (601, 611) used for electrical insulation are made of non-conductive material.

5. The motor according to any one of the preceding claims, characterized in that, The components (601, 611) used for electrical insulation are insulating discs (611).

6. The motor according to claim 5, characterized in that, The insulating disk (611) has a central circular hole (619).

7. The motor according to claim 6, characterized in that, The central circular hole (619) extends radially outward through a material-free free space (623), wherein the shape and position of the free space (623) are adapted to the predetermined positions of the winding conductors (8a, 8b, 8c) extending from the stator base.

8. The motor according to claim 7, characterized in that, The free space (623) is surrounded by a flange (613) at its edge.

9. The motor according to claim 8, characterized in that, The flange (613) includes radially inwardly pointing ribs (621).

10. The motor according to claim 9, characterized in that, The ribs (621) terminate radially inward at a predetermined equal interval relative to the center of the insulating disk (611), thereby ensuring that the circular hole (619) at the center is free of material.

11. The motor according to any one of the preceding claims, characterized in that, The electrical insulation elements (601, 611) at least cover the stator base (306) on their outer periphery or extend beyond the stator base.

12. The motor according to any one of the preceding claims, characterized in that, The motor has a rotor (26) that is supported such that it is at least partially surrounded by the stator (28).

13. The motor according to any one of the preceding claims, characterized in that, The motor is configured as an electrically driven air compressor (16).

14. The motor according to claim 13, characterized in that, The electrically driven air compressor (16) is configured to supply air or oxygen to the fuel cell stack (10) in the cathode system (14).

15. A fuel cell system (1) for generating electrical energy from hydrogen and oxygen, having an electric motor (16) according to any one of the preceding claims, and a fuel cell stack (10) for supplying air or oxygen to the fuel cell system (1).

16. An element (601) for electrical insulation, for providing electrical insulation between a compact conductor region (73) of an electric motor (16) according to any one of claims 1 to 14 and a stator base (306) of such an electric motor.

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