Electric drive with offset winding systems

Abstract

Electric drive with an electric machine having a stator with n winding systems, each having m phases, wherein several winding systems are inserted in circumferentially arranged slots of the stator and the number of slots is s = 2 * m * n² or an even multiple thereof, wherein the slots are filled alternately in the direction of rotation with a first winding system group (WG1) of windings of a first winding system and with a second winding system group (WG2) of windings of a second winding system, wherein the windings of each winding system group are arranged in directly successive slots and wherein in the first winding system group several phase groups (PG1, PG2, PG3) of different phases (U, V, W; X, Y, Z) follow one another, wherein in each phase group (PG1, PG2, PG3) several windings of the same phase (U; V;W) follow one another or a winding (U2+) is provided and wherein a winding (U2+) belonging to the same phase as the phase of the first phase group (PG1) of the second winding system group (WG2) is added to the last phase group (PG2) of the second winding system group (WG2), wherein the first winding system group (WG1) each begins and ends with a complete phase group (PG1, PG2, PG3) having several windings of the same phase and the second winding system group begins with a phase group (PG1) and ends with a phase group (PG1) having fewer windings than the intermediate complete phase groups of the second winding system group having several windings of the same phase.;

Description

[0001] Vehicles with electric drives feature an electric machine with a stator in whose slots windings are inserted. When these windings are energized, a rotating electric field is generated in synchronous or asynchronous motors, driving a rotor of the electric machine. In automotive applications, relatively high power levels are required, meaning the winding and slot structure cannot be arbitrarily fine. Instead, discrete slots are used, each containing a winding, typically occupying an angular range of approximately 7° or 10° to 15°. This discrete design of the mechanical or electromechanical structure results in ripple in the generated torque and the current flowing through the windings.

[0002] Such ripples are dampened by a DC link capacitor, but this represents a cost factor, and therefore there is an interest in keeping the ripple as low as possible and thus also the size of the DC link capacitor as small as possible. Furthermore, the torque ripple is also noticeable through fluctuating drive power (especially at low speeds) and through noise.

[0003] It is therefore an object of the invention to demonstrate a possibility by which an electric drive can be designed in such a way that only a small ripple (with regard to torque and / or with regard to load current) results.

[0004] This problem is solved by the subject matter of claim 1. Further areas of application, embodiments, features, properties and advantages arise with the subject matter of the dependent claims.

[0005] It is proposed to provide an electric drive with an electric machine in which several winding systems are provided in the stator, and where the winding systems are offset from one another (along or against the circumferential direction, i.e., from one slot to the next). There are contiguous phase groups, each containing several windings assigned to the same phase (and the same winding system). Within the phase groups, there are thus several adjacent windings occupying neighboring slots with windings of the same phase. This allows for an offset of the winding systems from one another that is smaller than the width of a phase group. For example, if there are phase groups comprising windings that extend over two adjacent slots, i.e.,If a phase group has a width of 2 (slots), then one winding system can be offset from another by a number of slots smaller than the width of the phase group (approximately only one slot or only one winding). This causes phase groups from different winding systems to overlap, thus reducing ripple. Overlap therefore represents a transition between different phase groups belonging to different winding systems. Because of this overlap, one phase group does not (when considering multiple winding systems) simply follow another; rather, there are overlaps that make the transition "smoother." Due to the reduced ripple, the DC link capacitor of the drive is less stressed, meaning the AC components are reduced, especially in the range of multiple harmonics relative to the fundamental frequency of the drive current.This allows the DC link capacitor to be designed with lower requirements and therefore more cost-effectively, while also resulting in lower noise generation compared to non-offset winding systems. A winding within the slot refers specifically to a portion of the winding that extends along the slot (i.e., in the axial direction), i.e., a section of the winding. A turn can extend along one slot, connect to another slot, and then extend along that slot. The direction of extension in the first slot is, in particular, opposite to the direction of extension to the next slot. The different directions of extension are shown with different signs in the figures.

[0006] An electric drive is described, comprising an electric machine with a stator containing n winding systems, for example, 2 (or 3 or 4). The electric drive is specifically a traction drive for a vehicle. Each of the n winding systems has m phases, for example, 3 (or 6). The stator has slots arranged around its circumference. These slots are axially aligned, i.e., parallel to the axis of rotation of the electric machine. The multiple winding systems are inserted into the slots. The number of slots s is 2 × m × n. 2or an integer or even multiple thereof. The slots are filled alternately in the direction of rotation with a first winding system group of windings and a first winding system, and with a second winding system group of windings of a second winding system. The two winding systems (or groups) can therefore alternate simply (pattern: A - B with two winding systems A and B) or alternate multiple times, with the two winding systems alternating multiple times along one revolution (pattern: A - B - A - B with two winding systems A and B). In a simple alternation, the second winding system group thus fills the remaining angle to the complete circumference that follows the first winding system group.Thus, the winding system groups are arranged sequentially, with no winding group (in a single layer) being repeated. In the case of multiple alternating windings, these groups are arranged in successive succession. Each winding system can be provided as a single winding system group or can be formed by several winding system groups. The first one or more winding system groups form the first winding system. The second one or more winding system groups form the first winding system.

[0007] If the windings are arranged in multiple layers, then a winding system group in the first layer is offset relative to the same winding system group in the other layer, in particular by a length of m phase groups + 1 slot or - 1 slot. The layers can thus each contain all winding systems, which can be present multiple times (along a circumference of the stator). Preferably, each layer contains phase groups from all winding systems. In the case of multiple layers, a winding system group in the first layer is offset relative to the same winding system group in the other layer, the offset being preferably smaller than the width of m phase groups. A winding system group thus includes all windings of a winding system (if the winding system group or...The winding system is not repeated along the circumference or across multiple layers) or includes a portion of the windings of a winding system (if these are repeated along the circumference or across multiple layers). Since each winding system has multiple phases, each winding system group is divided into multiple phase groups.

[0008] In the first winding system group, several phase groups of different phases follow one another. This also applies to the second winding system group, as well as to repetitions of the first and second winding system groups that occur in different positions and / or along the circumference. Within each winding system group, several phase groups can be repeated. With three phases U, V, W, several windings of the same phase occur side by side (pattern: U1, U2), followed by several windings of another phase (pattern: V1, V2). Within each phase group, several phases are thus arranged side by side, with each phase being represented by several (successive) windings of the same phase. In each phase group, several windings of the same phase follow one another.In each phase group, a number of consecutive windings of the same phase follow one another, corresponding to the phase number m (or an integer or even multiple thereof). This applies in particular to all phase groups of the first winding system or winding system groups thereof and preferably only to a subset of the phase groups of the second winding system or winding system groups thereof, especially those phase groups of the second winding system that do not form an end of the second winding system group or that do not connect to a phase group of the other winding system.

[0009] Thus, phase groups can exist (especially within a second winding system group) in which a phase is not represented by a number of m windings in m slots, but by a smaller number, e.g., a number of m - 1 windings in m - 1 slots. In particular, a phase in a phase group can also be represented by only a single winding, or this phase group can have single windings located at two opposite ends of the winding system group. The smaller number of windings for a phase in a phase group (at the beginning or end of a second winding system group) compared to m can result from the offset described here, which reduces the ripple.

[0010] In each winding system group, several phase groups of different phases preferably follow one another. Thus, the phase sequence is repeated multiple times within each winding system group. Here, the phase group represents a simple sequence of all m (identical) phases, while the winding system group repeats several of these simple sequences. A phase group is described as a simple sequence in which each phase is represented by one or, in particular, by several windings, but these windings of the same phase are arranged directly one after the other, and these successive windings or their phases are not repeated.Therefore, if there are windings to the phases U, V, W, then the phase group is defined by the windings of phase U, followed by the windings of phase V in a second phase group, followed by the windings of phase W in a third phase group, without repeating any other phases after phase W.

[0011] The winding system groups are offset from one another, in particular by a number of slots less than the number of phases m or by an integer multiple of the number of slots in a phase group, where this number is increased (or decreased) by 1. If the windings are provided in multiple layers, then the attaching winding can attach to a second winding system group that is in a different layer than the second winding system group from which it was offset. The attaching winding can thus attach to a second winding system group that is provided in a different winding layer. Therefore, a winding belonging to the same phase as the phase of the first phase group of the second winding system group in a first winding layer can attach to the last phase group or first phase group of the second winding system group, where this last phase group is in a different layer than the first phase group.A winding of the first phase group can be located in a first layer, while another winding of the same phase group (or a section of the same winding) is located in a different layer, provided both phase groups belong to the second winding system group. The offset resulting from the addition can therefore extend across layers. Thus, a winding from a first phase group can be offset to a phase group in a different layer or continued there. Adding a winding from a first phase group to the last (complete) phase group of the same (second) winding system does not refer to a specific direction of rotation in which "first" and "last" would be defined.Rather, the terms "first" and "last" phase group simply indicate that these are two phase groups at the ends of a second winding system group, whereby, as mentioned, the two phase groups in question can be located in different winding positions if multiple winding positions are present.

[0012] The drive can also be provided with three (or more) winding systems. According to one embodiment, the slots are alternately filled in one direction of rotation with windings from the first winding system group, with windings from the second winding system group, and with windings from a third winding system group. The three winding systems are thus each arranged in winding system groups. In the third winding system group, several phase groups of different phases follow one another. The third winding system group is therefore fundamentally arranged like the first two winding system groups. Two windings belonging to the same phase as the phase of the first phase group of the third winding system group are connected to, or continue from, the last phase group of the third winding system group.After one winding in the second winding system group has been offset to the last phase group in this manner, two windings (i.e., more windings than in the first winding systems) are now offset to the last phase group. Thus, the third winding system group is also offset (by one winding) to the second winding system group, or is offset by more than one winding to the first winding system group. With more than two winding systems, these are preferably offset in the same direction of rotation and uniformly offset from each other, i.e., offset by the same number of windings. If the second winding system group provides i windings that connect to the last phase group (and are taken from the first phase group), then, according to one embodiment, the third winding system group is offset by i windings (or more than one winding).The winding system group is offset by i slots relative to the second winding system group, which is taken from the first phase group and connected to the last phase group of this winding system group. Preferably, with increasing order of the winding system group, one more winding is taken from the first phase group of this winding system group and added to the last phase group.

[0013] In the second winding system group, compared to the first winding system group, one winding of the first phase group is moved to the other end, and with each further winding system group (third, fourth, ...) or with each further winding system, one more winding is moved from the first phase group to the phase group at the other end of the respective winding system group, or this winding is continued there.

[0014] The windings of each winding system group are preferably arranged in directly consecutive slots. One embodiment provides that the windings of each phase group belong to the same phase. Preferably, the windings belonging to the same phase and the same phase group are arranged in directly consecutive slots. This preferably applies to all phase groups that do not have windings attached to the last phase group(s) of the opposite end of the winding system group. According to an embodiment with multiple winding layers, different ends (of the same winding) are arranged in different positions. Preferably, different ends of the same winding are provided in successive phase groups of the same phase. In embodiments with multiple winding layers, successive phase groups can be provided in different winding positions.

[0015] There are embodiments in which only one winding system group is provided along the stator circumference. Other embodiments provide for several winding system groups to be repeated along a revolution or within a revolution. In this case, the winding system groups can be repeated alternately within a revolution (so that, for example, a second winding system group follows a first, and the second winding system group is followed by another first winding system group). Alternatively, or in combination with this, the phase groups within each winding system group can be repeated one or more times. This also applies to one revolution of the stator. Furthermore, it is possible for the winding groups to be repeated within several revolutions. This repetition over several revolutions leads, in particular, to multiple winding layers, so that the winding groups are repeated along the multiple winding layers within several revolutions.Different winding system groups or windings from different winding systems are located in the same slots (in all slots or only some of them). These are arranged offset from each other by at least one slot. Thus, different winding groups are provided largely overlapping in the same slots, but offset from each other. The second winding group can be offset from the first, preferably by a number of slots less than the number of consecutive slots with the same phase.

[0016] Another aspect is the connection between different phase groups of the same winding system group, in particular the electrical connection of the adjoining winding or winding section. The winding adjoining (or continuing) the last phase group of the second winding system group is connected to the first phase group of the second winding system group via an electrical connection. Preferably, the ends of the first winding of the first phase group and the winding adjoining the last phase group are adjacent. The electrical connection is preferably located at the phase group of the second winding system group that belongs to the same phase as the first phase group of the second winding system group. The connection is preferably located between this first phase group and the winding that adjoins (or continues) the last phase group of the second winding system group.where it is continued. The same applies to third and subsequent winding system groups: the appended winding(s) (or the winding section in the appended slot(s)) are preferably connected via a connection to the first phase group of the same winding system from which they are "taken." The term "taken" refers to the smaller number of slots of the first phase group of the second winding system group (compared to the number of slots occupied by the following phase group), with the difference being the last phase group. This difference, or the winding(s) of the last phase group, can be considered as what is taken from the first phase group, with the first (incomplete) phase group and the last (incomplete) phase group together being considered as a complete phase group (with the same number of slots as the second).

[0017] Successive phase groups of the same phase each have one end of the two opposite ends of the same winding. One end of the appended winding is preferably in a slot from which a first winding extends towards the first phase group (from which the appended winding was taken), and from which a further winding of the same phase extends in the opposite direction.

[0018] Furthermore, it can be provided that a first end of the winding of each phase group of the first winding system group is offset in the direction of rotation relative to the first slot of this phase group. A second end of this winding can be provided in the last slot of the subsequent phase group of the same phase. A winding system can also be provided that has ends from which a winding always extends in the same direction of rotation. This applies in particular to the first winding system group. A winding system group can also be provided that has ends from which a winding extends in one direction of rotation, and another winding extends in the opposite direction of rotation. Thus, starting from each end, there is a winding on both sides.The outer ends of the winding system group can be configured to each have a winding extending towards the opposite end, which also has a connection to a further end. The ends are preferably continued to a phase junction where a phase terminal of a winding system group is located.

[0019] As mentioned, the slots can be filled in multiple layers, resulting in several winding layers. Specifically, the slots can be filled with winding system groups in a first and a second layer. The first and / or second layer (winding layer) has a winding that belongs to the same phase as the phase of the first phase group of the second winding system group in that layer. Preferably, this winding is connected to the last phase group of the second winding system group in that layer.

[0020] The first layer is preferably offset from the second layer by a number of slots v, where v corresponds to the width of the first phase group (i.e., minus the attached winding). In other words, v = (m x number of windings per phase group) - 1 (or +1). The variable m corresponds to the number of phases. Windings of the same phase group are assigned to the same phase. Thus, the windings of the winding system group containing the first phase group from which a winding has been "taken" are located in the first layer, while the "taken" winding is located in the other layer. This simplifies the winding process.

[0021] Preferably, several or all windings are distributed across the first and second layers. In this configuration, some of the windings are located in the first layer, and another part, e.g., a second section, is located in the second layer. Preferably, different ends of a winding are located in different layers.

[0022] A specific example provides that the stator consists of n = 2 winding systems, each comprising m = 3 phases. The total number of slots in the stator is preferably s = 24. Here, the phase groups can be repeated once (per winding system), with the first three phase groups appearing circumferentially being the first ends of windings, and the second ends of these windings being present in the repetition of these phase groups. Thus, each phase group occurs twice per winding system (i.e., the first occurrence of the phase group and its single repetition). Another embodiment provides that the stator consists of n = 2 winding systems, each equipped with m = 3 phases, as in the preceding example. However, in this further embodiment, the phase groups are repeated three times each.The first phase groups to appear and their repetitions result in 4 phase groups per winding system, all belonging to the same phase. Since 2 winding systems each have 4 sequences of different phase groups, and each phase group has 2 slots, this results in a total of 48 slots in the stator.

[0023] Another example shows that the stator is equipped with a total of n = 2 winding systems. These each have a total of m = 3 phases. The sequence of the second winding group following the first is repeated once per revolution; thus, the first and second winding groups each occur twice. The second winding group is repeated directly over one revolution. The number of slots in the stator can be 48.

[0024] Furthermore, the stator can be configured to have a total of n = 2 winding systems, each with m = 3 phases. Along one revolution, two first winding system groups follow directly one another, followed by two directly consecutive second winding system groups. The two first winding system groups, viewed circumferentially, each comprise m = 3 phase groups that repeat once, thus forming forward and return sections of the same winding, as well as further m = 3 phase groups that repeat once, thus forming forward and return sections of the same winding (i.e., another winding). These are followed by the two second winding system groups, which are preferably configured like the two first winding system groups. Each phase group (except for the last and the first phase groups of the second winding systems) occupies two consecutive slots with winding sections / windings of the same phase.The number of slots in the stator is s = 48, i.e., twice the equation s = 2 × m × n. 2 and thus double 2 × 3 × 2 2 = 2 × 24.

[0025] According to a further aspect of the invention, the electric drive comprises an inverter and an inverter control circuit connected to it. The inverter is connected to the electric machine. The inverter control circuit is configured to provide pulse-width modulation (PWM) operation and block operation. In block operation, the phases of the electric machine are driven without PWM, i.e., without PWM modulation that would be aligned to a sinusoidal waveform. The inverter control circuit is further configured to activate PWM operation above a (predefined) speed limit. Below or not above the speed limit, the control circuit activates block operation.

[0026] Finally, the electric machine can be designed as a synchronous machine or as an asynchronous machine. The electric drive can be designed as an electric traction drive or as a starter generator for a motor vehicle.

[0027] The Fig. 1 to Fig. Figure 4 shows winding diagrams to illustrate exemplary embodiments of the invention.

[0028] In the Fig. Figure 1 shows a winding scheme with m = 3 phases, n = 2 winding systems, and s = 24 slots. This corresponds to the formula s = 2 × m × n 2= 2 × 3 × 4 = 24. The windings are divided into a first winding system group WG1, which represents the first winding system, and a winding system group WG2, which contains windings of the second winding system. In the circumferential direction, the second winding system follows the first winding system, with neither the first nor the second winding system group repeating. The first winding system group WG1 contains no windings of the second winding system, and vice versa. This method of grouping also applies to the subsequent figures.

[0029] Furthermore, the windings are grouped according to phase groups. Each winding system group WG1, WG2 contains several phase groups PG 1 to PG 3. Different phase groups are assigned to different phases. Phase group PG 1 is assigned to phase U, phase group PG 2 to phase V, and phase group PG 3 to phase W. This applies particularly to the first winding system or the first winding system group WG1. As shown in the following figures, the phase groups PG 1 to PG 3 of the second winding system group can also be designated with different letters than the phases of the first winding system group, in order to further distinguish them via the reference symbols. Thus, the phase groups PG 1 to PG 3 of the second winding system group can also be designated with phase designations that do not correspond to UVW, but are designated with X, Y, Z, cf. Fig. 2 - Fig. 4.

[0030] Due to the visible separation between the winding system groups WG1 and WG2 in the Fig. 1. The phases of the different winding systems can be easily separated.

[0031] The phase groups PG 1, PG 2 and PG 3 of the two winding systems WG 1 and WG 2 of the Fig. Each winding in the first winding system group (WG 1) has two windings of the same phase. These follow each other directly within the same phase group (exception: the first and last phase groups of the second winding system group, which are incomplete). With increasing electrical angle α or with increasing slot number G, the phase system groups PG 1, PG 3, and PG 2 of the first winding system group (WG 1) alternate in this sequence. Thus, the windings in question are arranged in 30° increments (electrical angle), with the windings of the same phase appearing twice in immediate succession. Consequently, pairs of the same phase (forming the same phase group) are arranged consecutively in the first winding system group (WG 1).

[0032] This is also the case for the second winding system group, provided that the electrical angles alpha 30° to 300° are considered. However, compared to the first winding system group WG1, the second winding system group WG2 is offset by half a stator circumference minus one slot. This refers to the geometric offset. There is an offset of alpha = 30° (electrical) between winding system groups WG1 and WG2. The first winding system group occupies slots G = 1...12, while the second winding system group occupies slots G = 13...24. The direction of the dislocation is opposite to the increasing angle or the increasing number of slots. Thus, the direction of the dislocation in the Fig. 1. The direction of the phase sequence of phases U, V, W. Returning to the geometric offset of group WG2 to group WG1, the first phase group PG1 of group WG2 comprises only one winding (U2+) and occupies only the slot at the angle 0°, or slot G = 13, and not the subsequent slot. The other winding belonging to the first phase group PG1 of the second winding system group WG2, viewed in the direction of the increasing angle, is connected to the last (complete, i.e., occupied with 2 windings) phase group PG2 of the second winding group. The electrical winding range 0° - 30° of the first phase group (G= 1, 2) of the first winding system group WG1 thus includes the (single winding U2+ of the) first phase group (U2+ of PG 1) of the second winding system group WG2 as well as a winding (W2-, slot 14) of the following phase group PG3 of the second winding system group WG2.Therefore, with respect to the electrical angle of the winding scheme, there is no butt-to-butt offset between the different winding systems, but rather an overlapping offset. Similar to brickwork, a transition between two different phase groups of one winding system group (e.g., PG1 → PG3 of slots G = 13, 14, WG2 between 0° and 30°) coincides with a contiguous phase group of the other winding system group (e.g., PG1 of slots G = 1, 2, WG1, angle interval 0° - 30°). This overlap preferably refers to the electrical angle profile and may also refer to the geometric winding profile. The offset is possible because a sufficient number of slots are provided, or rather, a sufficient number of windings or slots per phase group, to allow for such an overlapping displacement. In particular, the offset between the winding system groups is smaller than the number of windings per (complete) phase group.

[0033] In the Fig. Figure 1 shows the two winding system groups in succession. The first 12 slots, 1 to 12, contain the first winding system group, WG 1, and the following slots, 13 to 24, contain a further 12 windings belonging to the second winding system group. The angle alpha is to be understood as the electrical angle, where the offset by one slot corresponds to an angular offset of 30° (electrical angle).

[0034] Further winding diagrams are shown below, in which two winding system groups are provided differently in the same stator, whereby an offset between the winding systems is also provided there, which is smaller than the angular width or number of slots occupied by a continuous phase group. In other words, in the further embodiments shown, the number of successive windings in the same phase group is also greater than the offset between the winding system groups (possibly plus / minus 180 degrees) in order to allow, in addition to the offset, an overlap of phase groups from different winding systems.

[0035] The Fig. Figure 2 also shows a winding pattern with 48 slots. Here, n = 2 winding systems are used (U, V, W on one side, X, Y, Z on the other). Each of the two winding systems thus has m = 3 phases. With an increasing number of slots G, the phase groups PG 1 to PG 3 of the winding systems repeat regularly, whereby the winding sequence U, W, V defines (with an increasing number of slots G) a winding direction that is opposite to the direction of rotation of the rotor, provided that the phases U, V, W are phase-shifted to each other in the usual way (U: 0°, V: 120°, W: 240°).

[0036] The Fig. Figure 2 shows in the upper half the first two winding system groups WG1, WG1', which together form the first winding system. The two first winding system groups WG1, WG1' are arranged consecutively and occupy slots G = 1 to 24. The winding system group WG1' corresponds to a repetition of the winding system group WG1. In the lower half of the Fig. Figure 2 shows the second winding system, which is formed from two consecutive second winding system groups WG2 and WG2'. These two second winding system groups occupy slots G = 25 to 48. In each winding system group WG1, WG1', WG2, WG2', the phase groups PG1, PG3, and PG2 alternate (in this order along the increasing number of slots G). This sequence is repeated once in each winding system group. In the first winding system (groups WG1 and WG1'), consecutive phase groups are formed, each containing two windings of the same phase. The first phase group of a given phase may contain the first sections of windings, while the subsequent phase group of the same phase may contain the second sections of the same windings. An example of this is slots 1 and 2, which contain the first sections of two windings, the second sections of which are located in slots 7 and 8.in a phase group PG1 (grooves 7, 8) that occurs as a repetition and belongs to the same phase (U) as the first of the phase group PG1 (grooves 1, 2).

[0037] The lower half of the Fig. Figure 2 shows the first and second of the two second winding system groups WG2 and WG2'. The first phase groups PG1 of the second winding system groups WG2 and WG2' each have only a single winding, see PG1 of slot G = 25 and PG1 of slot G = 37. Following these first phase groups with only one winding per slot in each of the winding system groups WG2 and WG2' are the phase groups PG3, PG2, PG1, ..., each of which has one more winding, i.e., two windings. The first of the second winding system groups WG2 extends over slots 25–36, which follow the first winding system (slots 1–24). The last complete (i.e., with two windings) phase group PG2 of winding system group WG2 (slots G = 34, 35) is followed in slot 36 by a winding corresponding to a phase group PG1 that is incomplete (i.e., extends over only one slot). This is directly followed by the second winding system group WG2' of the second winding system.This begins in slot G = 37 with the first (and therefore incomplete) phase group PG1 (comparable to PG1 of slot 25 of the preceding winding system group WG2 of the same winding system). Following this, in winding system group WG2' (as in winding system group WG2), are phase groups PG3, PG2, PG1, PG3, PG2 (slots 38-47), which are complete. Next to these is a slot with an incomplete phase group PG1 (slot 48), i.e., a single winding. The two incomplete phase groups PG1 (slot 37, slot 48) of the second winding system group WG' each have only one winding, i.e., one winding (or slot) less than the intervening phase groups or one winding (or slot) less than the first phase group PG1 of one of the first winding system groups WG1, WG1'. For each of the second winding system groups WG2, WG2' there is therefore a first phase group PG1, which has a winding that is connected to the respective second winding system group orto whose last (complete) phase group of the winding system group.

[0038] The incomplete phase groups PG1, or rather the winding appended to the last (complete) phase group, belong to the same phase as the first phase group PG1 of winding system group WG2, which is also incomplete and, in particular, has only one winding. It can be seen that the two phase groups PG1 (slot 25) and PG1 (slot 48) belong to the same phase, namely phase X. Phase groups with the same last digit belong to the same phase. The second winding system group WG2 thus begins with an incomplete phase group, i.e., a phase group that has fewer windings than each of the following phase groups in slots 26 to 47. The last phase group PG2, which is complete in this sense (here: two windings), is followed by an incomplete phase group PG1, which has fewer windings than the preceding complete winding groups.The incomplete phase group appended to the last (complete) phase group extends over a number of slots equal to the number of slots of a complete phase group minus the number of slots of the first, incomplete phase group. If a complete phase group has two slots, then each incomplete phase group occupies one slot. This corresponds to one slot before and one slot after the complete phase groups. The two incomplete phase groups PG1, slot 25 and PG1, slot 36 of the second winding system group WG2 together have as many windings as one of the intervening (complete) phase groups of slots 26 to 35. The two incomplete phase groups PG1, slot 37 and PG1, slot 48 of the further second winding system group WG2' together have as many windings as one of the intervening (complete) phase groups of slots 38 to 47.Phase group PG1, slot 25 and slot 36, as well as phase group PG1, slot 37 and slot 48, are each divided, with the remaining phase groups of the respective winding system group WG2, WG2', located between them. These divided phase groups are assigned to the same phase and are assigned to the same continuous winding, as shown in the rows below the two tables. Fig. 2 can be seen.

[0039] Below the two lines of the Fig. Figure 2, which shows phase groups PGn, phase PH, and slot G, schematically depicts individual winding paths. The winding path itself is visible, as are the slot boundaries between two different slots, represented as vertical lines, in which the winding runs. For the first winding system group WG1, it can be seen that the first winding end WA1, i.e., the winding start, is not formed by the winding in the first slot of the first phase group PG1, but by the second slot (G = 2) of the first phase group of the first winding system group WG1. The second end of this winding path, i.e., the winding end WE1, is located in the phase group PG1 that follows the phase group PG1 in which the winding start WA1 is located. It can be seen that in the phase group PG1 in which the winding end WE1 is located, the winding end is not in the first slot 7, but in the second slot 8.The depicted winding thus encompasses two (= number of phases minus 1) complete phase groups PG 3, PG 2. The same applies to the subsequently depicted winding of slots 13 to 20 in the winding system WG1', where the winding start WA 2 of phase group PG 1 (slots 13, 14) is also located in the second slot of this phase group. The second end, i.e., the winding end WE 2, is also provided in the subsequent phase group PG 1 of slots G = 19, 20, and is located there in the second slot of this phase group. This corresponds to slot 20.

[0040] Since the second winding group WG2 does not begin with a complete phase group PG 1, the winding start WA 3 of a winding sequence of the second winding system is provided in slot 25. A connection V1 exists between the subsequent repetition of the same phase group PG 1, specifically from slot 30 (i.e., the first winding of this phase group PG 1), and the subsequent winding that begins in the following slot (slot 31). The winding sequence continues to the subsequent phase group PG 1 of slots 36 and 37, i.e., the phase group PG 1 that follows the first complete phase group PG 1 of the first phase. The winding is routed back as shown in the first (and only) slot of the incomplete phase group PG1 in slot 36, this slot carrying a winding section of an incomplete phase group which is attached to the last complete phase group PG2 (slots 34, 35).This results in a winding end WE 3 in the first complete phase group PG 1 of the first phase, cf. slot 31, whereby the winding end WE3 is located in the second winding of phase group PG 1 of slots 30, 31. Thus, the winding end WE 3 of the second winding system group WG2 is located in the second slot of the first complete phase group PG 1, which has the same phase as the very first phase group PG 1 of the second winding group WG 2. While in WG1, starting from the first winding end WA 1, the winding continues to the next winding group PG 1 of the same phase, and then back to the first phase group PG 1 of group WG 1, for the second winding system, the winding continues to reach a third phase group of the same phase. From there, in the second winding group WG2, WG2', the winding is returned to the second phase group PG1 of the same phase.This is also shown for a further winding of the second winding system group WG2', which begins in slot 37 (cf. winding start WA4), continues to the next phase group PG1 of the same phase, namely to slot 42. From there, a further connection V2 leads to a subsequent winding section, which reaches the next phase group PG1 of slot 48, and from there is led back to phase group 42, 43 (there: to the second winding of this phase group in slot 43). Thus, a first part of this winding with ends WA4, WE4 extends from a complete phase group PG 1 (there the second slot) to the next (complete) phase group of slots 42, 43, in order to be continued from there to the next (incomplete) phase group PG 1 of slot 48.From there, the winding is routed back to the second slot of the middle phase group PG1, which is located midway between the right phase group PG1 of slot 48 and the left phase group PG1 of slots 36 and 37. This middle phase group PG1 is the only complete phase group of this phase in the second winding system group WG2'. This also applies to the middle phase group PG1 of the second winding system group WG2, which lies before the winding system group WG2'. It should also be noted that winding paths extend in both directions from the complete middle phase group PG1; the complete middle phase group PG1 corresponds to an axis of symmetry for winding paths extending from it and which are routed back from a first and last, incomplete phase group of the same phase.

[0041] The Fig. 3 shows how the Fig. 2 a winding pattern for two winding systems, each with three phases, wherein the winding systems are housed in the 48 slots of the stator. While Fig. 2 with consecutive slot number G, first the first winding system groups WG1, WG1' one after the other and then the second winding system groups WG2, WG2' one after the other are present in the stator, are in the Fig. 3. The winding system groups are alternately divided into two parts. This results in the Fig. 3. Two first winding system groups WA1, WA1' and two second winding system groups WA2, WA2', which together constitute the two winding systems. The first part of the first winding system, i.e., the first winding system group WA1, is followed by the first part of the second winding system, i.e., the second winding system group WA2. This is followed by the second first winding system group WA1', which represents the second part of the first winding system, and then by the second second winding system group WA2', i.e., the second part of the second winding system. The two winding systems are thus divided into several parts, with the parts of different winding systems alternating.

[0042] This is also evident from the phase designation, where phases U, V, W are assigned to the first winding system groups (i.e., the first winding system), and phases X, Y, Z to the second winding system groups (i.e., the second winding system). It is further evident that in Fig. 3 the first winding system groups WG1, WG1' each begin with a complete phase group PG1 (see slots 1, 2 and 25, 26) and also end with a complete phase group (see slots 11, 12 and 35, 36).

[0043] In contrast, in Fig. 3. The second winding system groups, i.e., the winding system groups of phases X, Y, Z, with a phase group PG1 that has fewer windings than the following phase group or fewer than a complete phase group. In the case shown, the first phase group of the second winding system group WG2 (as seen with increasing slot number) has only one winding, see slot 13. This also applies to the last phase group PG1 of this first part of the second winding system, namely slot 24. Slots 13 and 24, each with only a single winding of the same phase, can be considered together as a phase group, which, however, does not have consecutive windings but rather windings spaced apart from one another. Between the windings of this phase group are 5 (m × n - 1) complete phase groups, see slots 14-23.

[0044] The first part of the second winding system, i.e., the second winding system group WG2 (slots 13 to 24), is followed by the first (and also complete) phase group PG1 (slots 25, 26) of the second part of the first winding system, which corresponds to the first phase group PG1 of the further first winding system group WG1'. The second part of the second winding system, i.e., the further second winding system group WG2', begins with slot 37, which, like the last phase group PG1 of the second winding system group, is incomplete and thus has fewer windings than a complete phase group. In the case shown, a complete phase group spans 2 slots. The two incomplete phase groups PG1 of slots 37 and 48 span only one (1) slot, or together they cover as many slots as one of the complete phase groups. The slots or windings of the two incomplete phase groups PG1 of slots 37, 48 are separate from each other.The complete phase groups (all phase groups of the second part of the second winding system group) are located between the windings of the incomplete phase group PG 1 in slots 37 and 48. The two incomplete phase groups can be considered a single, common phase group whose slots are not directly adjacent to each other, but are separated by several (complete) phase groups, in particular by the slots of 5 (n x m - 1 or 2 * m - 1) complete phase groups.

[0045] As in the Fig. 2 is in the Fig. Figure 3 below the tables shows how some example windings are arranged.

[0046] It can be seen that the first depicted winding begins in the second slot (G = 2) of the first phase group PG1 of the first occurring first winding system group WG1, i.e., in a phase group PG1 that is complete. It ends in the subsequent repetition of phase group PG1 of the same phase, specifically in the second slot (G = 8) of the second phase group PG1, which has the same phase as the first occurring phase group PG1 of slots 1 and 2. This also applies to the further first winding system group WG1' (i.e., the second part of the first winding system) with slots 25 to 32. Thus, for the first phase group PG1 of the first winding system group WG1, there is a first winding that occupies two consecutive slots and encompasses the two phase groups PG3 and PG2, these two phase groups PG3 and PG2 having a different phase than the phase of the first phase group PG1. This winding is doubled.The first winding shown (with ends WA3, WE3) of the second winding system group WG2 is also doubled. However, the two turns of the winding do not encompass the same phase groups, but different phase groups. The diagram shows that the first turn between slots 13 to 18 encompasses phase groups PG 3, PG 2 (single configuration), and the second turn encompasses the phase groups PG 3, PG 2 found in slots 20 to 23, i.e., repetitions of the aforementioned phase groups PG 3, PG 2, which are encompassed by the first turn. A connection V1 allows the first turn to be continued to the second turn.

[0047] It can be seen that the second turn has a winding end WE2, which is located at one end of the turn facing the first turn with the winding start WA2. The same applies to slots 37 to 42, where a first turn encompasses a simple iteration of the phase groups PG 2, PG 3 (see slots 38-42), while a second turn encompasses the subsequent phase groups PG 3, PG 2, i.e., their repetitions in slots 44-47. The resulting butterfly shape is applied to the second winding system group, while for the first winding system group, turns are used that encompass the same winding groups or the same slots.

[0048] Finally, the Fig. Figure 4 shows another exemplary winding diagram for a stator with 48 slots. This is shown in Fig. The winding diagram shown in section 4 consists of two layers, L1 and L2. The layers are arranged one above the other in the same slots. The winding diagrams of the Fig. 1 - Fig. 3 are preferably single-layered. While in the Fig. 4. Since the first layer L1 begins with windings of the first winding system, the second layer L2 begins with windings of the second winding system. In the first layer L1, the phase groups PG 1 to PG 3 of the first winding system are repeated four times (sequence PG1, 3, 2, 1, 3, 2) up to slot 24, whereupon the windings of a second winding system are connected. Here too, the second winding system begins with an incomplete phase group, i.e., in this case with a single winding in slot 25, followed by a phase group PG3 of a different phase.

[0049] The second layer L2 is shifted 5 slots relative to the first layer in the direction of increasing slot number. This shift corresponds to the number of slots filled by three consecutive complete phase groups, minus 1. The shift of the second layer relative to the first layer does not correspond to an integer multiple (e.g., m-fold) of the number of slots in a complete phase group, but rather to such a multiple minus or plus an integer fraction of the number of slots in a complete phase group. In the second layer L2, the winding scheme begins (with slot G = 1) with phase groups of the second winding system group or the second winding system.

[0050] In particular, the second layer L2 initially contains two complete phase groups PG3 and PG2 of the second winding system group, cf. slots G = 1 to 4 with the windings or winding sections Z6, Z5, Y6, and Y5. An incomplete winding group PG1 of the second winding system group follows in slot 5, cf. X5. The corresponding other winding section X5+ of this phase group PG1 is located directly before the first slot, i.e., in slot 48, but there in the first layer and not in the second layer. Thus, the two windings of this phase group (or the two incomplete phase groups) are not only separated from each other by two complete phase groups, but are also located in different layers. The single winding X5- of the second winding system group in slot 5 (in the second layer L2) is followed by four complete repetitions of complete phase groups of the first winding system group.Thus, windings of the first winding system group exist in the first and second layers.

[0051] Following slot 30 is an incomplete phase group (i.e., a single winding) of the second winding system group. The other end of this winding section X4- in the second layer of slot 30 is located in the first layer, designated X4+. Here again, the windings of the incomplete phase groups are not only separated from each other by several phase groups, but are also located in different layers. In the second layer, following this winding X4- of slot 30 (i.e., following the incomplete phase group in question), there are three repetitions of a sequence of m = 3 complete phase groups, which are assigned to different phases, as well as, in slots 1-4, two complete phase groups PG3 and PG2 of phases other than the winding of slot 30. These phase groups following slot 30 belong to the second winding system. This is followed by an incomplete phase group of the second winding system group, i.e.,A single winding has the same phase as the previously mentioned incomplete phase group (X5 - slot G=5 in position L2). Complete phase groups of the first winding system follow. Therefore, complete phase groups of the other, first winding system follow the other incomplete phase group of the second winding system.

[0052] In the Fig. 4. Windings whose first two digits are the same are designated as the same winding, with the following sign indicating the different ends. This also applies to the Fig. 1 to Fig. 3.

[0053] Phase bus connections can be provided between windings of the same phase, even if they are arranged in different phase groups. These bus connections lead to a common phase terminal. As already explained with reference to the other figures, a turn of the first winding system group can begin in the first phase group, have one or more turns that encompass the subsequent phase groups of other phases, and then continue with one or more turns that encompass the subsequent phase group of other phases. The other end can be located in the phase group of the same phase as the beginning, with this phase group situated between the phase groups of other phases, i.e., in the second phase group of the same phase as the first phase group in which the winding begins.

[0054] Particularly in two-layer winding systems, the winding start for a phase group of the second winding system can be located in the first repetition of a phase group, i.e., in the first complete phase group. From there, it can have one or more turns in the direction of decreasing slot number towards the preceding (incomplete) phase group, and can continue from the first complete phase group to the subsequent phase group (in the direction of increasing slot number). From there, the winding scheme can continue in this way, and a terminal can be located in the first complete repetition of the phase group of the same phase. Starting from the terminals, there are thus turns extending in both directions, i.e., in the direction of increasing and decreasing slot number.

Claims

[1] Electric drive with an electric machine having a stator with n winding systems, each having m phases, wherein several winding systems are inserted in circumferentially arranged slots of the stator and the number of slots s = 2 * m * n 2or an even multiple thereof, wherein the slots are filled alternately in the direction of rotation with a first winding system group (WG1) of windings of a first winding system, and with a second winding system group (WG2) of windings of a second winding system, wherein in the first winding system group several phase groups (PG1, PG2, PG3) of different phases (U, V, W; X, Y, Z) follow one another, wherein in each phase group (PG1, PG2, PG3) several windings of the same phase (U; V; W) follow one another or a winding (U2+) is provided and wherein a winding (U2+) belonging to the same phase as the phase of the first phase group (PG1) of the second winding system group (WG2) is attached to the last phase group (PG2) of the second winding system group (WG2). [2] Electric drive according to claim 1, wherein the slots are alternately filled in the direction of rotation with the first winding system group (WG1) of windings of the first winding system, with the second winding system group (WG2) of windings of the second winding system, and with a third winding system group of windings of a third winding system, wherein in the third winding system group several phase groups of different phases follow one another, wherein two windings belonging to the same phase as the phase of the first phase group of the third winding system group are attached to the last phase group of the third winding system group. [3] Electric drive according to claim 1 or 2, wherein the windings of each winding system group (WG1; WG2) are arranged in directly successive slots (1 - 12; 13 - 24), and wherein the windings of each phase group (PG1 - PG3) belong to the same phase and are arranged in directly successive slots. [4] Electric drive according to one of the preceding claims, wherein the winding system groups (WG1, 2) are repeated alternately within a revolution, or the phase groups (PG1 - PG3) are repeated within each winding system group within a revolution, or the winding groups are repeated within several revolutions and different winding groups are arranged in the same slots, but offset from each other by at least one slot. [5] Electric drive according to one of the preceding claims, wherein the winding (X1- / PG1 / 30) adjoining the last phase group (Y2+ / PG2 / 28+29) of the second winding system group (WG2) is connected in series via an electrical connection (V1) to a subsequent winding (X1- / PG1 / 31) of the first phase group (PG1) of the second winding system group (WG2), wherein the electrical connection (V1) is located at the phase group of the second winding system group which belongs to the same phase as the first phase group (PG1) of the second winding system group (WG1, WG2). [6] Electric drive according to one of the preceding claims, wherein successive phase groups (PG1 / 1, 2 or PG1 / 7, 8) of the same phase (U) each have one end of the two opposite ends (+, -) of the same winding. [7] Electric drive according to one of the preceding claims, wherein a first end (WA1) of the winding (U1) of each phase group (PG1) of the first winding system group (WG1) is offset in the direction of rotation relative to the first slot (G=1) of this phase group (PG1) and a second end (WE1) of this winding is provided in the last slot (G = 8) of the following phase group (PG1) of the same phase (U). [8] Electric drive according to one of the preceding claims, wherein the stator has a total of n = 2 winding systems, each having a total of m = 3 phases, and the total number of slots of the stator is s = 24, or wherein the stator has a total of n = 2 winding systems, each having a total of m = 3 phases, the sequence of the second winding system group (WG2) following the first winding system group (WG1) is repeated once along one revolution, a repetition of the second winding system group (WG2) directly follows the second winding system group (WG2) along one revolution, and the total number of slots (G) of the stator is s = 48, (Implementation example8) or wherein the stator has a total of n = 2 winding systems (WG1, WG2), each having a total of m = 3 phases, with a repetition of the first winding system group (WG1) directly following the first winding system group (WG1) along one revolution, with a repetition of the second winding system group (WG2) directly following the second winding system group (WG2) along one revolution, and the total number of slots in the stator is s = 48. (Implementation example A). [9] Electric drive according to one of the preceding claims, further comprising an inverter and an inverter control circuit connected thereto, which is connected to the electric machine, wherein the inverter control circuit is configured to provide pulse width modulation operation and block operation, in which the phases of the electric machine are controlled without pulse width modulation, wherein the inverter control circuit is further configured to set the pulse width modulation operation above a speed limit and to set the block operation below the speed limit. [10] Electric drive according to one of the preceding claims, designed as an electric traction drive of a motor vehicle.

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