Stator with a wave winding

Abstract

The invention relates to a stator (1) with a wave winding (2) comprising a plurality of electrical conductors (3) which are arranged in winding slots (4) of the stator (1), wherein the wave winding (2) has a permanent chording (5) in which the slot pitch (6) on the I-pin winding head side (7) differs from the slot pitch (8) on the opposite side (9).

Description

[0001] Stator with a wave winding

[0002] The present invention relates to a stator with a wave winding comprising a plurality of electrical conductors arranged in slots of the stator.

[0003] Wave windings are commonly used to enable a compact and robust winding arrangement in stators, particularly those intended for use in electric motors. In particular, these windings offer the advantage of high mechanical stability and allow for efficient use of space within the stator, thereby enabling high power densities.

[0004] However, stators with wave windings, as known in the prior art, also have significant disadvantages. A key problem is that the phase assignment of the slots in conventional designs is usually such that each slot is assigned to a single phase. This leads to an uneven distribution of electromagnetic forces, especially when the mechanical and electrical loads change during operation. This uneven distribution causes undesirable effects such as increased torque ripple and an increase in noise, vibration, and harshness (NVH). Such effects are particularly problematic in applications such as electric vehicle powertrains, as they can impair driving comfort and reduce the efficiency of the powertrain.

[0005] US2009261683A1 describes an approach in which the winding of a wave winding in a stator is optimized by a specific arrangement of the electrical conductors in the slots. However, the fundamental problem of uneven phase distribution remains, which continues to lead to suboptimal electromagnetic properties and reduced efficiency.

[0006] Another problem lies in optimizing the winding head height. To utilize the installation space efficiently, it is crucial that the winding heads are designed to be as compact as possible. However, conventional wave windings often do not allow for uniform air distribution between the conductors, leading to a suboptimal winding head design. This not only increases the electrical resistance but also the thermal stress on the winding, ultimately limiting the performance and lifespan of the electric motor.

[0007] The object of the invention is therefore to provide a stator with a wave winding that avoids or at least reduces the disadvantages known from the prior art.

[0008] This problem is solved by a stator with a wave winding comprising a plurality of electrical conductors arranged in slots of the stator, wherein the wave winding has a permanent chord in which the slot step on the I-pin winding head side differs from the slot step on the opposite side.

[0009] This stator offers the advantage that the permanent tautness of the winding allows for an asymmetrical conductor arrangement, where the slot step on the I-pin winding head side differs from that on the opposite side. This results in improved distribution of electrical loads and a reduction in torque ripple, as well as noise and vibration (NVH). Consequently, the electric motor operates more efficiently and quietly, which is particularly important in automotive applications. Furthermore, the winding heads can be designed more compactly, optimizing installation space and simultaneously reducing winding resistance.

[0010] The invention thus relates to a wave winding for electrical machines in which a permanent chord of the winding is implemented to achieve an improved distribution of the winding phases in the stator slots. This chord consists in the fact that the slot step – the distance between the conductors of different phases, measured in slots – differs on the I-pin winding head side from the slot step on the opposite side. This approach differs from the prior art, in which the slot step is usually symmetrically and uniformly distributed over the entire winding.

[0011] Technically, the slot spacing describes the distance between conductors belonging to a specific phase, measured in the number of slots. It is calculated as the product of the number of phases (nphases) and the number of holes (q), which describes the number of slots per magnetic pole and phase. In a simple example with three phases and a number of holes of 3, the standard slot spacing is 9, meaning that conductors of the same phase are separated by 9 slots each.

[0012] The invention provides that the slot step on the I-pin winding head side differs from that on the opposite side, resulting in an asymmetrical winding arrangement. For example, the slot step on the I-pin side can be 8, while on the opposite side it is 10, or vice versa. Other combinations such as 7 / 11 or 11 / 7 are also conceivable. This variability in the slot step allows for a more flexible winding design, which helps to minimize undesirable electromagnetic effects, such as torque ripple, and to improve space utilization in the stator.

[0013] This permanent chord is particularly advantageous for windings with a non-integer number of slots, such as q = 1.5, 2.5, 3.5, or 4.5. In such cases, a standard winding with or without local chords is difficult to implement because achieving a symmetrical distribution of the winding phases across the slots becomes problematic. However, the permanent chord according to the invention allows for a practical and efficient winding design. For example, with a slot count of 2.5 and three phases, slot step combinations such as 7 / 8, 8 / 7, 6 / 9, or 9 / 6 can be realized. This asymmetrical arrangement of the slot steps leads to an optimized phase distribution and better adaptation of the winding to the available installation space of the motor.

[0014] Permanent magnet winding thus offers the possibility of implementing winding geometries that would not be feasible with conventional methods, while simultaneously increasing the efficiency and performance of the motor. It contributes to the reduction of torque fluctuations and the optimization of space utilization in the stator, particularly in applications where available installation space is limited or asymmetrical winding arrangements are required.

[0015] First, the individual elements of the claimed invention are explained in the order in which they are mentioned in the claim set, and subsequently, particularly preferred embodiments of the invention are described.

[0016] For the purposes of this patent application, a wave winding is an electrical winding in which the conductors are guided through the slots of the stator in a wave-like, alternating arrangement. In contrast to conventional windings, where the conductors are arranged in successive slots, in a wave winding the conductors are guided across multiple slots, creating a characteristic wave pattern. This arrangement allows for more efficient use of the available space in the stator and enables the same conductor to occupy multiple slots, resulting in a more even distribution of the electrical load.

[0017] The wave winding serves to generate a rotating magnetic field by ensuring that the electrical currents in the conductors flow in defined sections of the stator according to the number of phases and the frequency. These currents generate magnetic fields in the slots, which together produce a rotating magnetic field in the air gap between the stator and rotor. The wave-like arrangement of the conductors helps to minimize torque ripple and makes motor operation smoother and more efficient. Furthermore, the alternating routing of the conductors through different slots improves the magnetic coupling between the phases, resulting in higher electromagnetic efficiency.

[0018] The wave winding can be implemented in various configurations, depending on the materials used and the design. Preferably, the conductors are made of copper, as this material exhibits excellent electrical conductivity and enables current flow with minimal losses. Alternatively, aluminum can be used, which is lighter and offers advantages in cost-sensitive applications. The conductors can advantageously be insulated with high-temperature-resistant materials such as polyimide or fiberglass to withstand the thermal stresses during operation.

[0019] Structurally, the wave windings can be designed as so-called hairpin windings, in which the conductors are inserted into the slots as prefabricated, U-shaped wire segments and then welded together. This design allows for high packing density and precise arrangement of the conductors in the slots, resulting in higher efficiency and improved thermal performance. Another preferred embodiment is the distributed wave winding, in which the conductors are arranged to generate the most uniform possible distribution of magnetic flux in the stator. Here, the waveform of the conductors is distributed over the entire circumference of the stator, further reducing electromagnetic losses.

[0020] The wave winding can be designed either symmetrically or asymmetrically in its wave shape in order to keep the winding heads as compact as possible and to make optimal use of the installation space.

[0021] Electrical conductor

[0022] For the purposes of this patent application, an electrical conductor associated with a wave winding in a stator is a component that carries the electric current within the windings and forms the basis for generating the magnetic field that drives the electric machine. These conductors are preferably made of a material with high electrical conductivity, such as copper or aluminum, with copper being the preferred material due to its excellent electrical and mechanical properties. Aluminum can be used as an alternative if a lower weight is required.

[0023] The electrical conductor in a wave winding is characterized by its arrangement in a predetermined pattern within the stator slots to ensure optimal electromagnetic interaction. The conductors preferably have a rectangular cross-section, as this shape allows for dense packing of the conductors in the slots, resulting in a higher fill factor and better utilization of the available space. The conductors in the wave winding can be bent into a predefined shape to achieve the most compact and efficient winding possible. The conductors can be insulated or uninsulated, with insulation preferably applied to prevent short circuits between adjacent conductors. This insulation can consist of painted or plastic-coated materials.

[0024] Permanent longing

[0025] For the purposes of this patent application, a permanent chord is a permanent and fixed deviation in the slot step between the I-pin winding head side and the opposite side of a stator with a wave winding. This deviation, which extends over the entire circumference of the stator, ensures that the spacing between the conductors arranged in the stator slots is not symmetrical, but varies. While in conventional windings the slot step is the same on both sides of the stator, the permanent chord allows for an asymmetrical distribution of the conductors in the slots. The permanent chord is designed such that the slot step differs between the I-pin winding head side and the opposite side.

[0026] The function of permanent magnet slitting is therefore primarily to achieve improved phase distribution and electromagnetic balance in the stator. By selectively varying the slot step, the electric and magnetic fields can be optimized, leading to a reduction in undesirable phenomena such as torque ripple and vibrations (NVH).

[0027] For the purposes of this patent application, a slot step is the distance, measured in the number of slots, between two electrical conductors arranged in different slots that are assigned to a common phase of a multiphase winding. The slot step thus describes the relationship of the winding wires' positions to one another along the circumference of the stator and determines how the electrical conductors are distributed in the stator slots. The slot step therefore refers to the arrangement of the electrical conductors in the stator slots. Each electrical conductor of a specific phase is positioned in a slot, with the distance to the next conductor of the same phase defined by the slot step. A change in the slot step, as introduced in this invention by a permanent strain gauge, results in an asymmetrical distribution of the conductors along the winding, leading to an improved phase distribution.This has the advantage that the electromagnetic properties of the stator can be specifically influenced, for example to reduce the torque ripple or to minimize the winding head height.

[0028] The slot step can have various configurations. In a preferred embodiment, the slot step on the I-pin winding head side can be smaller or larger than on the opposite side to create an asymmetrical winding. This variation allows for differentiated adaptation of the winding to the mechanical and electrical requirements of the motor. Another advantageous embodiment provides that the slot step remains constant but is given a defined chord to ensure optimized air distribution between the wires. Furthermore, the slot step can deviate from half a hole in windings with an odd number of holes, which may be necessary in certain electric motor designs to adapt the spatial arrangement of the windings to tight installation space constraints.

[0029] Number of holes

[0030] For the purposes of this patent application, the number of holes describes the number of stator slots in an electric machine per magnetic pole and phase. The number of holes thus indicates how many slots in the stator are available for the windings of each phase responsible for a magnetic pole. This value is a crucial parameter for the design of the winding arrangement in the stator and significantly influences the electromagnetic and mechanical properties of the motor. The number of holes is calculated as the ratio of the total number of stator slots to the number of magnetic poles and phases of the system. For example, a number of holes of 3 means that there are three slots per pole and phase in which the windings are arranged. A number of holes of 2.5 indicates that an average of 2.5 slots are available per pole and phase, suggesting a non-integer and asymmetrical distribution of the windings.

[0031] The function of the number of holes is to control the distribution of the windings in the stator depending on the magnetic poles and phases of the motor.

[0032] A higher number of holes generally results in a finer winding spacing, which improves electromagnetic coupling and increases motor performance. A lower number of holes can lead to a coarser winding spacing, which is advantageous in certain cases to reduce undesirable effects such as torque ripple or to meet specific space requirements in the stator.

[0033] Preferably, the number of holes is selected to be optimally matched to the number of magnetic poles and phases of the motor. This enables a uniform distribution of the magnetic fields and optimal utilization of the slots for the windings. Possible embodiments include both integer hole counts, such as 3 or 4, and non-integer hole counts, such as 2.5, which allow for an asymmetrical winding distribution. By selecting a suitable number of holes, the motor's performance can be specifically tailored with regard to efficiency, torque characteristics, and smooth running.

[0034] Advantageous embodiments of the invention

[0035] According to an advantageous embodiment of the invention, it can be provided that the groove step on the I-pin winding head side is phased. x q 1 and on the opposite side nphasexq+1 is, where nphases is the number of phases and q is the number of holes.

[0036] This design offers the advantage that the slot step on the I-pin winding head side varies by a fixed value compared to the opposite side. This creates a particularly efficient winding arrangement, enabling a more uniform phase distribution in the slots. This variation minimizes electromagnetic losses, thus increasing the motor's energy efficiency. Furthermore, this design reduces the mechanical stress on the windings, which can extend the component lifespan.

[0037] According to a further preferred embodiment of the invention, it can also be provided that the groove step on the I-pin winding head side is nphasexq+1 and on the opposite side is nphase xq-1, where nphases is the number of phases and q is the number of holes. This configuration allows for additional flexibility in the winding arrangement and can offer even better adaptation to specific operating requirements in certain applications. In particular, the phase distribution in the slots can be further optimized to selectively influence the magnetic properties of the stator.

[0038] Furthermore, according to an equally advantageous embodiment of the invention, it can be provided that the groove step on the I-pin winding head side is phased. x q _ 2 and on the opposite side n-phases xq+2, where nphases is the number of phases and q is the number of holes. This combination of features offers the advantage of allowing even finer tuning of the stator's electromagnetic properties. This further reduces unwanted harmonic vibrations and eddy currents, leading to increased efficiency and lower heat generation during operation. This can be particularly beneficial in high-power applications or under varying load conditions.

[0039] According to a further particularly preferred embodiment of the invention, it can be provided that the groove step on the I-pin winding head side is phased. x q+2 and on the opposite side n-phases xq-2, where nphases is the number of phases and q is the number of holes. The larger difference in the slot spacing results in an even more uniform distribution of electrical and mechanical loads across the conductors. This can be particularly advantageous in applications with high thermal and mechanical load-bearing capacity requirements. Furthermore, this variant contributes to minimizing vibrations and noise. The invention can also be further developed such that the number of holes q is a non-integer value, with the slot spacing on the I-pin winding head side being nphasesxq-0.5 and on the opposite side nphasesxq+0.5, where nphases is the number of phases and q is the number of holes. Introducing a non-integer number of holes q in conjunction with permanent winding offers the advantage that the winding can also be used with hole counts that are problematic in traditional winding designs.This improves the manufacturability of stators with odd numbers of holes, offering greater flexibility in the design of electric motors. Particularly in specialized applications where installation space is limited, this can lead to better motor customization.

[0040] In a further preferred embodiment of the invention, it can also be provided that the number of holes q has a non-integer value, wherein the groove step on the I-pin winding head side is nphasexq+0.5 and on the opposite side is nphase x q —The value is 0.5, where nphases is the number of phases and q is the number of holes. This variation offers the advantage of allowing even greater flexibility in adapting the winding arrangement. In certain operating modes, this configuration can provide improved adaptation to the electromagnetic fields in the stator, which can further increase the motor's performance. This is particularly advantageous for motors with variable operating requirements.

[0041] It can also be advantageous to further develop the invention such that the electrical conductors in the area of ​​the radially inner I-pins have a U-shape, which offers the advantage that the conductors can be arranged more efficiently in the slots. The U-shape enables a more compact winding geometry, which further reduces the winding head height. Another advantage is the simpler connection of the terminal due to fewer I-pins, since the U-shape reduces their number compared to other embodiments.

[0042] According to a further preferred embodiment of the invention, the wave winding can be provided with a layer-swapping option in which the positions of the electrical conductors are interchanged in different winding stages. The layer-swapping option within the wave winding offers the advantage that the arrangement of the conductors in the different winding stages can be flexibly adapted. Layer swapping allows for the compensation of unevenness in the distribution of electrical loads, resulting in more uniform heating of the winding and a longer service life of the insulation materials. This flexibility can also be used to adapt the winding to specific operating conditions, thereby improving the overall performance of the motor.

[0043] Finally, the invention can also advantageously be implemented such that the wave winding comprises several partial wave windings, each partial wave winding having a permanent chord. This offers the advantage that the winding can be constructed modularly, which simplifies manufacturing and provides greater flexibility in adapting the winding to different motors or operating requirements. Furthermore, the use of multiple partial wave windings can reduce the thermal and electrical stress on the individual windings.

[0044] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0045] It shows:

[0046] Figure 1 shows a wave winding and a slot layout of a stator, which are known from the prior art.

[0047] Figure 2 shows a first embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0048] Figure 3 shows a second embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0049] Figure 4 shows a third embodiment of a shaft winding with a corresponding slot layout plan of a stator; Figure 5 shows a fourth embodiment of a shaft winding with a corresponding slot layout plan of a stator.

[0050] Figure 6 shows a fifth embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0051] Figure 7 shows a sixth embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0052] Figure 8 shows a seventh embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0053] Figure 9 shows an eighth embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0054] Figure 10 shows a ninth embodiment of a wave winding with a corresponding slot layout plan of a stator,

[0055] Figure 11 shows a wound stator in a cross-sectional view.

[0056] The embodiments of Figures 2-10 have in common that they each show, based on a slot layout plan of a stator 1 and a separately shown wave winding 2, a stator 1 with a wave winding 2 comprising a plurality of electrical conductors 3 arranged in slots 4 of the stator 1, wherein the wave winding 2 has a permanent chord 5 in which the slot step 6 on the I-pin winding head side 7 differs from the slot step 8 on the opposite side 9.

[0057] Figure 2 shows a wave winding 2 in which a plurality of electrical conductors 3 are arranged in the slots 4 of the stator 1, as also sketched in Figure 11. The wave winding 2 has a permanent chord 5 in which the slot step 6 on the I-pin winding head side 7 differs from the slot step 8 on the opposite side 9. In the illustrated embodiment, the slot step 6 on the I-pin winding head side 7 has a value of 8, while the slot step 8 on the opposite side 9 has a value of 10. This arrangement allows for multi-phase occupancy of the slots 4, as can be seen, for example, in slots 10, 13, 19, and 22.

[0058] The permanent tension 5 optimizes the slot occupancy 4 to achieve a uniform air distribution between the conductors 3 of the same winding stage, resulting in a reduction of the winding head height. The stator 1 shown in Figure 2 illustrates a winding combination in which a slot step of 8 is provided for each stage and each conductor 3 on the I-pin winding head side 7, while a slot step of 10 is implemented on the opposite side 9. The slot step 6 is therefore nphases xq-1 on the I-pin winding head side 7 and nphases xq+1 on the opposite side 9, where nphases is the number of phases and q is the number of holes.

[0059] Figure 2 shows a permanent chord winding 5 in a stator 1 with three holes and three phases. The winding arrangement shown has an asymmetrical distribution of the slot steps 6, 8. While the standard slot step in such a configuration is usually 9, Figure 2 shows that the slot step 6 on the I-pin winding head side is 8 for each stage and each electrical conductor 2, while the slot step 8 on the opposite side is 10. This asymmetrical chord 5 is clearly visible. In the winding diagram of Figure 2, the slots 4 are arranged to be multi-phase. For example, slots 10, 13, 19, and 22 are shown as multi-phase, meaning that these slots 4 contain electrical conductors of 3 different phases. This multi-phase arrangement allows for optimized space utilization and contributes to the reduction of torque ripple and electromagnetic interference.

[0060] Additionally, Figure 2 shows that the electrical conductors 3 are arranged identically for each stage, which allows for the definition of an optimal bending angle. This optimized geometry minimizes the air gap between the wires, resulting in an optimal winding head height and simultaneously reducing the electrical resistance of the winding. Figure 3 shows an embodiment in which the slot step 6 is on the I-pin winding head side 7 nphasexq+1 and on the opposite side 9 nphase x q-1 is where nphases is the number of phases and q is the number of holes.

[0061] Figure 4 shows an embodiment in which the groove step 6 is on the I-pin winding head side 7. x q-2 and on the opposite side 9 nphases x q+2, where nphases is the number of phases and q is the number of holes.

[0062] Figure 8 shows another embodiment in which the number of holes q is a non-integer value, with the slot jump 6 on the I-pin winding head side 7 n-phases x q-0.5 and on the opposite side 9 nphases x q+0.5, where nphases is the number of phases and q is the number of holes. The number of holes q can also be a non-integer, with the slot step 6 on the I-pin winding head side 7 nphases x q+0.5 and on the opposite side 9 nphases x q is 0.5, where nphases is the number of phases and q is the number of holes.

[0063] Figure 5 shows an embodiment in which the electrical conductors 3 in the region of the radially inner I-pins (left end of the winding mat in Figure 5) have a U-shape and a chord 5. This provides a connection only at the radially outermost layer after the winding mat has been rolled up, whereas, for example, in the embodiment of Figure 4, a connection to the terminal is made at the radially inner diameter and radially outer diameter of the rolled-up winding mat.

[0064] Figure 6 shows another embodiment in which the wave winding 2 with the permanent chord 5 has a layer exchange option in which the positions of the electrical conductors 3 are exchanged in different winding stages.

[0065] Figure 7 shows an alternative embodiment in which the embodiments from Figures 5 and 6 have been combined. Figure 9 shows a further embodiment in which the wave winding 2 known from Figures 2-3 has been supplemented with local chords. With permanent chords 5, the slot step 6, 8 is consistently asymmetrical along the entire wave winding 2. This means that the slot step 6 on the I-pin winding head side 7 permanently differs from that on the opposite side 9. This difference remains the same over the entire length of the wave winding 2, resulting in a continuous, uniform asymmetrical winding arrangement. In contrast, local chords occur only at certain points along the wave winding 2. The slot step varies at specific points or in limited areas of the wave winding 2, while a constant standard slot step is used in other areas.Local tautness is used to correct or optimize local effects, for example, in areas where unwanted magnetic interference may occur. It is a type of fine-tuning to solve specific problems without making the entire winding asymmetrical.

[0066] As can be seen from Figure 10, an embodiment is also conceivable in which the wave winding 2 comprises several partial wave windings, each partial wave winding having a permanent chord 5.

[0067] The winding diagrams shown here depict an arrangement of six conductors (3) per slot (4), three pole pairs, and a number of holes of either 3 or 2.5, combined with a stepped blade. This design allows for a flexible and efficient winding arrangement in the stator. However, the concepts presented are not limited to these specific parameters. They can also be applied to winding arrangements with 2, 4, 6, 8, 10, or 12 conductors per slot (4), and they support a wide variety of motors with 2 to 8 pole pairs. Similarly, hole counts of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 can be accommodated, providing a wide range of adaptation options for different motor requirements. Furthermore, the use of a continuously variable blade is also possible to allow for even greater flexibility in winding design.This variability in design makes it possible to optimally adapt the winding concept to different requirements regarding installation space, performance, and electromagnetic efficiency. The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Insofar as the claims and the foregoing description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a hierarchy.

[0068] List of reference signs

[0069] 1 Stator

[0070] 2 wave windings, 3 conductors

[0071] 4 grooves

[0072] 5 Longing

[0073] 6 groove

[0074] 7 I-pin winding head side 8 groove jump

[0075] 9 Opposite side

Claims

Claims 1. Stator (1 ) with a wave winding (2) comprising a plurality of electrical conductors (3) arranged in slots (4) of the stator (1 ), characterized in that the wave winding (2) has a permanent chord (5) in which the slot step (6) on the I-pin winding head side (7) differs from the slot step (8) on the opposite side (9).

2. Stator (1 ) according to claim 1 , characterized in that the slot step (6) on the I-pin winding head side (7) is nphasexq-1 and on the opposite side (9) is nphasexq+1, where nphases is the number of phases and q is the number of holes.

3. Stator (1 ) according to claim 1 or 2, characterized in that the slot step (6) on the I-pin winding head side (7) is nphasexq+1 and on the opposite side (9) is nphasexq-1, where nphases is the number of phases and q is the number of holes.

4. Stator (1 ) according to one of the preceding claims, characterized in that the slot step (6) on the I-pin winding head side (7) is nphasexq-2 and on the opposite side (9) is nphasexq+2, where nphases is the number of phases and q is the number of holes.

5. Stator (1 ) according to one of the preceding claims, characterized in that the slot step (6) on the I-pin winding head side (7) is nphasexq+2 and on the opposite side (9) is nphasexq-2, where nphases is the number of phases and q is the number of holes.

6. Stator (1 ) according to one of the preceding claims, characterized in that the number of holes q is a non-integer size, wherein the slot step (6) on the I-pin winding head side (7) is nphasexq-0.5 and on the opposite side (9) is nphasexq+0.5, where nphases is the number of phases and q is the number of holes.

7. Stator (1) according to one of the preceding claims, characterized in that the number of holes q is a non-integer size, wherein the slot step (6) on the I-pin winding head side (7) is nphasexq+0.5 and on the opposite side (9) is nphase x q — 0.5, where nphases is the number of phases and q is the number of holes.

8. Stator (1 ) according to one of the preceding claims, characterized in that the electrical conductors (3) have a U-shape in the region of the radially inner I-pins.

9. Stator (1 ) according to one of the preceding claims, characterized in that the wave winding (2) has a layer exchange option in which the positions of the electrical conductors (3) are exchanged in different winding stages.

10. Stator (1 ) according to one of the preceding claims, characterized in that the wave winding (2) comprises several partial wave windings, each partial wave winding having a permanent chord (5).

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