Motor stator

Abstract

The invention relates to a stator (1) of an electric motor (2), the stator having a rotating shaft (3) and being used for at least a double three-phase voltage supply device (4); wherein the electric motor (2) has a first three-way subsystem (5) and a second three-way subsystem (10), the first subsystem having a first group (6) of branches: a first branch (7), a second branch (8), and a third branch (9), and the second subsystem having a second group (11) of branches: a fourth branch (12), a fifth branch (13) and a fifth branch (14). ), a sixth branch (14); wherein the stator (1) comprises at least one cylindrical base body (15) having a plurality of slots (16, 17), the slots extending in an axial direction (18) and a radial direction (19) respectively and arranged side by side in a circumferential direction (20), and wherein teeth (21) are formed between the slots respectively; wherein a plurality of electrical conductors (22) are arranged in each slot (16, 17), the electrical conductors being arranged in the slots (16, 17) as distributed windings.

Description

Technical Field

[0001] The invention relates to a stator of an electric machine, which has at least two multi-branch subsystems. Background Art

[0002] An electric motor vehicle drive comprises an electric machine used as a traction machine for a motor vehicle and power electronics and is usually designed as a three-way Or three-phase. For drives with further increased power in the future, the required power can be input in a space-optimized manner by more than just one three-phase converter. It is expedient here to feed the motor with two three-way subsystems by two three-phase converters with half the power.

[0003] The motor basically consists of a fixed part (stator or ) and the movable parts (rotor or ). The stator comprises, for example, a cylindrical base body having a plurality of slots, the slots extending in the axial direction and the radial direction and arranged side by side in the circumferential direction, and teeth are formed between the slots. Electrical conductors are arranged in the slots, wherein each conductor is respectively assigned to at least one winding branch.

[0004] For a three-phase voltage supply (or power supply), for example, a stator winding which can be designed in a three-way star circuit can be designed in such a way that only conductors respectively assigned to one winding branch and one phase are arranged in each slot when the winding pitch shortening (i.e., the shifting of conductors of the same phase / same branch in adjacent slots) is eliminated. Slots with conductors of different winding branches and therefore different phases are arranged alternately in the circumferential direction.

[0005] Such a stator winding can also be constructed with a plurality of multi-branch subsystems, i.e., for example, with two three-branch winding systems. The subsystems can be controlled, for example, by independent converters and connected in parallel to one another in the DC voltage intermediate circuit. With regard to the winding method of the stator winding, the known rules for the placement of the windings (e.g. for hairpin windings, rod windings, wave windings, etc.) must be observed in order to ensure the same surface effect in the conductor and the same amplitude of the induced voltage in the individual branches of the subsystems. As a result, (in conventional winding designs) a large overlap area is formed in the slots in which both the branches of the first subsystem and the branches of the second subsystem are arranged. Due to the large spatial overlap area between the subsystems and the resulting spatial proximity of the branches of the different subsystems, these branches are strongly inductively coupled to one another.

[0006] When operating such an electric machine having two independently controlled subsystems arranged in the stator so as to overlap one another due to the winding method, very high current fluctuations, i.e. high amplitudes of certain current harmonic oscillations, are observed, which can be attributed to the inductive coupling of the subsystems. This results in high harmonic oscillation losses, i.e. additional losses. Particularly high current fluctuations occur in particular when pulse width modulation interleaving (PWM) is provided, i.e. when the clock control cycles between the subsystems are offset in time (PWM: pulse width modulation).

[0007] In order to avoid such strong inductive coupling between the different winding branches, it is known to use alternative winding types, for example concentrated windings (tooth coil windings), in which each tooth is wound by only one conductor branch.

[0008] Alternatively, a distributed winding can be used, in which the coil sides of the coil are not positioned in slots adjacent to one another, but in slots that are spaced farther apart from one another in the circumferential direction. As a result, in the region of the winding head (or winding end), the coil ends of a plurality of coils that extend outside the slots and connect the coil sides overlap. In the known distributed winding, the subsystems do not overlap one another in the region of the slots, i.e. are arranged spatially completely separated from one another, thereby reducing inductive coupling.

[0009] When specifying hairpin technology, the type of winding is specified. However, in distributed winding, the complete spatial separation of the subsystems leads to a taller winding head structure. This increases the axial length and the installation space of the electric drive without increasing the power and torque. However, the torque density or power density is reduced.

[0010] DE 10 2016 224 178 A1 relates to a plurality of partial winding systems or partial windings which can be used with different numbers of phases, here double three-phase.

[0011] DE 10 2011 016 123 A1 discloses an electromechanical machine, the stator of which has slots for arranging windings. The windings are arranged in the slots in the manner of wave windings.

[0012] DE 10 2018 124 784 A1 relates to a stator in which each conductor branch is designed in the manner of a wave winding.

[0013] DE 10 2004 036 727 A1 relates to an electric machine in which the winding systems are arranged in layers one above the other in slots of a stator. Summary of the invention

[0014] The technical problem to be solved by the present invention is to at least partially solve the problems described in connection with the prior art. In particular, a stator should be provided which is equipped with a plurality of multi-branch subsystems and can be operated by at least two multi-phase converter units, wherein the additional losses during operation are as small as possible.

[0015] This technical problem is solved according to the invention by a stator of an electric machine. The features described individually in the invention can be combined with one another in a technically appropriate manner and can be supplemented by the facts explained in the description and / or details in the drawings, wherein further embodiments of the invention are shown.

[0016] A stator of an electric motor is proposed, which is particularly used for a dual three-phase voltage supply device and has a rotating shaft and a plurality of multi-branch subsystems. The electric motor includes at least one first three-branch subsystem and a second three-branch subsystem, the first subsystem having a first group of branches: a first branch, a second branch, and a third branch, and the second subsystem having a second group of branches: a fourth branch, a fifth branch, and a sixth branch. The stator includes at least one cylindrical base body having a plurality of slots, the slots extending in the axial direction and the radial direction respectively and arranged side by side in the circumferential direction, and teeth are formed between the slots respectively. A plurality of electrical conductors are arranged in each slot, and the electrical conductors are arranged in the slots as distributed windings. Each conductor is respectively assigned to a branch and a subsystem. In at least one first slot of the stator, only a conductor assigned to only one branch is arranged, and in at least one second slot, at least two conductors assigned to different branches, especially branches of different groups, are arranged.

[0017] The electric machine is in particular a synchronous machine (SM), in particular a permanently excited machine (PSM), a reluctance machine (SRM), a separately excited machine (FSM) or an asynchronous machine (ASM). The electric machine comprises a stationary stator and a rotating rotor. The rotor is arranged in particular in the radial direction outside the stator, but preferably inside the stator. A shaft, for example a drive shaft, can be driven by the rotor.

[0018] The stator is particularly designed to be driven by a plurality of multiphase converters or control units. At least two three-phase alternating current systems are provided. The individual phases of each group of branches are particularly offset from each other by 120 (angle) degrees. More than two three-phase alternating current systems can also be provided. It is not necessary to provide a plurality of three-phase alternating current systems. For example, two five-phase or m-phase alternating current systems (m represents the number of phases) can also be provided.

[0019] The stator comprises in particular a cylindrical base body, which has a plurality of slots, also referred to as slits, on an outer circumferential surface or on an inner circumferential surface or on an end side. The slots extend in an axial direction or in a radial direction, in particular parallel to or transverse to the axis of rotation. The slots have a depth extending in a radial direction when arranged on the circumferential surface or in an axial direction when arranged on the end side, a width extending in a circumferential direction, and a length extending in an axial direction when arranged on the circumferential surface or in a radial direction when arranged on the end side. A tooth is formed between every two slots.

[0020] In the slots, starting from the bottom of the slots, electrical conductors are stacked or positioned one on top of the other and are arranged electrically insulated from one another. The conductors are respectively electrically conductively connected to the branches of the subsystems. The electrical conductors are formed in particular by wires or pins or rods, which are arranged on the stator in the form of turns. Each turn consists of an outgoing wire (Hinleiter) and a return wire (Rückleiter), which respectively represent the turn sides in two different slots and can be composed of one wire or a plurality of wires connected in parallel. The coil is formed by at least one turn. Similar to the turns, the coil also consists of two sides, which are arranged in two different slots like the turn sides. The electrical conductor forms a coil. The application of current to the electrical conductor generates a rotating field in a known manner, which interacts with the rotor field for driving the rotor.

[0021] The conductors are arranged in the slots, in particular, in the manner of a distributed winding. In a distributed winding, the coil sides of the coil are not arranged in slots adjacent to one another, but are positioned in slots arranged at a distance from one another in the circumferential direction. In the winding head arranged outside the slots, for example in the end-side region, the conductors extend at least in the circumferential direction and connect the coil sides to one another.

[0022] In particular, conductors stacked one above the other and arranged adjacent to one another in a slot have different courses in the stator, ie they extend outside of this slot into different preceding and / or succeeding slots.

[0023] The stator comprises in particular a soft magnetic stator lamination stack, which consists, for example, of individual laminations or a magnetic composite material. In addition, the stator comprises conductors arranged in slots, which together form a winding. The conductors are in particular designed as known hairpins or rods, which are inserted into the slots in the axial direction or in the radial direction and are connected to each other in an electrically conductive manner in at least one winding head, for example, arranged on the end side. The slots of the stator are in particular designed to be electrically insulated relative to the conductors. The stator also has, in particular, a connection element for a shunt connection in relation to the wiring arrangement (or connection).

[0024] A plurality of first slots arranged adjacent to one another in particular form a first annular segment of the stator, and a plurality of second slots arranged adjacent to one another form a second annular segment. The annular segment in particular comprises a plurality of first slots or a plurality of second slots arranged adjacent to one another. The annular segment extends around the rotation axis of the motor within a (certain) angular range.

[0025] Preferably, only conductors which are assigned either to the first group or to the second group are arranged in the first groove of the first annular segment.

[0026] At least one branch of a subsystem or of an alternating current system extends, in particular, only within a defined annular segment in a first slot. The branch of the subsystem together with the remaining branches of the same subsystem in the same annular segment forms a partial stator, which can be considered as a partial electric machine together with the rotor. Thus, on the one hand, annular segments are particularly achieved in which there is no spatial overlap of different subsystems and, on the other hand, annular segments are achieved in which there is a spatial overlap of subsystems.

[0027] Here, the number, size, etc. of annular segments or areas with and without overlap depend on the specific winding and machine design (number of AC systems, number of branches and phases, number of holes, number of pole pairs, number of slots, etc.) and can be designed adaptively according to these boundary conditions.

[0028] The advantages of this embodiment of the stator with a hairpin winding design over conventional hairpin winding designs lie in particular in the good inductive decoupling of the individual subsystems. This property is important, for example, for redundant systems.

[0029] The advantage of this embodiment in the design of a winding with a completely inductively decoupled winding system (in which only one branch and conductor of a subsystem is arranged in each slot and in which the subsystems are thus completely spatially separated, i.e. no overlapping regions are provided) is that electromagnetically ineffective return structures or return wires need not be provided in the winding head and require additional installation space. The winding head is therefore designed to save space.

[0030] Thus, in the proposed stator, the positive property of good inductive decoupling of the various subsystems can be achieved, while at the same time a space-saving wrapping design or a space-saving guidance of the conductor in the wrapping can be achieved.

[0031] Compared with the traditional hairpin winding design, there are no disadvantages in the geometric design of the winding head, and with regard to the generated current harmonic oscillations and harmonic oscillation losses, the new hairpin winding design with multiple multi-branch subsystems has obvious advantages, which can be attributed to the partial inductive decoupling.

[0032] By presenting separate areas in which different subsystems are spatially separated and therefore do not overlap each other, the inductive coupling between the individual subsystems can be reduced. The coupling induction or mutual inductance between the branches of the different subsystems that occurs in the winding method or winding design proposed here can be reduced accordingly. As a result, when the individual subsystems are controlled independently, the mutual inductive influence between the different subsystems can be significantly reduced. When the coupling induction between the subsystems is thus smaller, the current fluctuations caused by the corresponding other subsystems (and due to the coupling induction) are smaller and reduced in the two AC systems. Since the amplitude of the undesirable current harmonic oscillations, especially the current harmonic oscillations caused by clock control (or pulse control) is thus smaller, the harmonic oscillation losses are reduced by the new winding design. Here, the harmonic oscillation losses include both the additional current heat losses in the stator winding and the losses in the electrical steel sheets, magnets or rotor windings, etc. (depending on the machine type).

[0033] The novel winding design is therefore particularly advantageous in cases where, for example, PWM cycles or carrier signals of subsystems (e.g. when pulse duration modulation is used) are desirably shifted relative to one another (PWM interleaving) and the switching times between the branches of the same phase of the subsystems are different. In conventional winding designs with a plurality of AC systems, significant current fluctuations and thus high-frequency current harmonic oscillations that lead to additional losses occur in the case of PWM interleaving and without measures for inductive decoupling, whereas the proposed winding design can significantly reduce current fluctuations and additional losses in the case of PWM interleaving. In this case, the current fluctuations differ only slightly compared to a winding design with completely decoupled, i.e. non-overlapping, subsystems and therefore differ only slightly or are worse compared to windings of different subsystems without overlapping regions in the stator.

[0034] In the case of PWM interleaving, the carrier signals or PWM cycles of the different subsystems are shifted relative to each other, in particular by an offset angle. PWM interleaving is used in particular when the capacitor load of a central intermediate circuit capacitor is to be reduced. As a result, a smaller effective capacitor alternating current or a smaller capacitor voltage fluctuation enables a reduction in the capacitance and the capacitor installation space. This allows costs and installation space for the capacitor to be saved.

[0035] In this case, PWM interleaving is only one exemplary possible use for the proposed winding design, which is particularly advantageous with regard to inductive decoupling of the subsystems and the lowest possible mutual inductive influence of different subsystems.

[0036] The proposed embodiment of the stator can basically be used for all electric machines with bar / hairpin windings in a wide variety of different winding designs.

[0037] In particular, all first slots of conductors of one group are arranged in a first continuous annular segment. In particular, all first slots of conductors of a first group are arranged in a first continuous annular segment and all first slots of conductors of a second group are arranged in a further continuous annular segment.

[0038] In particular, a second ring segment having a second groove is arranged between the first ring segments.

[0039] In particular, at least one conductor assigned to the first group and at least one conductor assigned to the second group are arranged in each second groove of the second annular segment.

[0040] In particular, in each second groove of the second annular segment and starting from the groove bottom, conductors assigned to different branches and subsystems are arranged at least partially alternately, in particular stacked one on top of the other.

[0041] In particular, in each second slot, the number of conductors assigned to specific branches and subsystems is respectively the same. For example, three conductors of a first branch of a first group and three conductors of a fourth branch of a second group are present in a slot.

[0042] In particular, a number of second slots corresponding to the number of different groups are arranged next to one another in the circumferential direction, wherein the second slots have an identical arrangement of conductors assigned to different branches.

[0043] In particular, a number of second grooves corresponding to the number of different branches of all groups are arranged side by side in the circumferential direction. In particular, in the second annular section, six second grooves are arranged side by side in the case of three branches per group and two groups.

[0044] The stator in particular comprises at least one first annular segment and a second annular segment, preferably at least two first annular segments and two second annular segments, particularly preferably more than two first annular segments and more than two second annular segments, wherein the number of first grooves of at least one first annular segment is greater than the number of second grooves of at least one second annular segment.

[0045] In particular, the conductor extends between the coil start and the coil end through a plurality of slots and is arranged in at least one first slot and one second slot.

[0046] The stator comprises in particular a maximum of four annular segments (eg in the case of two subsystems). Each first annular segment comprises in particular an identical angular extent in the circumferential direction. Each second annular segment comprises in particular an identical angular extent in the circumferential direction but different from the first annular segment.

[0047] In the case of three subsystems, there may also be more than four annular segments. The number of annular segments depends on the subsystems (AC systems) to be inductively decoupled. The number of annular segments can be selected as a function of the number of subsystems.

[0048] Furthermore, a drive system for an electric machine having the stator is proposed. The drive system comprises power electronics having at least one DC voltage intermediate circuit and a first converter and a second converter, the DC voltage intermediate circuit having an intermediate circuit capacitor for providing a voltage and a variable current for driving the electric machine, the first converter for providing a voltage to the electric machine with a first group of phases, the second converter for providing a voltage to the electric machine with a second group of phases. The two converters generate, in particular, pulse width modulated signals or PWM signals from the DC voltage intermediate circuit, wherein the first pulse width modulated signal of the first converter and the second pulse width modulated signal of the second converter can be generated with a time offset relative to one another (so-called PWM interleaving).

[0049] Each converter generates a voltage for the motor in particular by cutting off a block voltage from the DC voltage intermediate circuit with a time offset. This cutting is called pulse width modulation (PWM). The currents obtained in the individual branches are particularly close to sinusoidal.

[0050] When using a plurality of subsystems, the PWM interleaving makes it possible in particular to dimension the intermediate circuit capacitor to be significantly smaller than in an AC system of the same power having only three phases (ie having only one converter).

[0051] The harmonic oscillating currents reduced by the novel winding design during PWM interleaving make it possible, in particular, to reduce the electrical losses in the electric machine and in the power electronics or converter.

[0052] Furthermore, a motor vehicle is proposed which comprises at least a drive train having an electric machine as a traction drive, wherein the electric machine has the drive system described.

[0053] The connection of the stator to multiple converter systems, for example, can provide higher power, for example, for driving a motor vehicle. The operation of the converter when generating PWM signals that are offset from each other in time, i.e., with PWM interleaving, may cause additional current harmonic oscillations to be generated in the turns of the motor. This occurs in particular when the conductors of the first group are arranged adjacent to the conductors of the second group, for example, in a slot. In order to reduce this effect, it is particularly recommended that the conductors of the shunts of different groups are separated from each other as far as possible in space. This is achieved in particular by arranging the electrical conductors of the three shunts assigned to the first group in an annular section, and the electrical conductors of the three shunts assigned to the second group in another annular section. However, a second annular section is additionally provided, in which the shunts of different groups are laid in a common slot. This can decisively reduce the structural space of the winding head, and the effect of the additionally generated current harmonic oscillations only occurs to a lesser extent.

[0054] In particular, the statements concerning the stator can be transferred to the drive system and the motor vehicle and vice versa.

[0055] The use of the indefinite article ("a"), in particular in patent claims and in the description of the claims, is to be understood as (a component) itself and not as a numeral. Accordingly, the terms or components introduced by them are to be understood as being present at least once but in particular also being present multiple times.

[0056] It should be noted carefully that the numerals used here ("first", "second", ...) are primarily (only) used to distinguish between a plurality of objects, dimensions or processes of the same type, i.e., in particular, do not necessarily specify a correlation and / or sequence of these objects, dimensions or processes with respect to one another. If a correlation and / or sequence is necessary, this will be explicitly stated here or will be apparent to a person skilled in the art when studying the specifically described design. As long as components can occur multiple times ("at least one"), the description of one of these components applies equally to all or most of these components, but this is not mandatory. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention and the technical environment are described in detail below with reference to the accompanying drawings. It should be noted that the invention should not be limited to the described embodiments. In particular, as long as it is not explicitly shown otherwise, some aspects of the facts described in the drawings can also be extracted and combined with other components and cognitions in this specification. In particular, it should be noted that the drawings and especially the dimensional relationships shown are only schematic. In the drawings:

[0058] Figure 1 The drive system is shown;

[0059] Figure 2 Shown in accordance with Figure 1 The stator winding of the drive system;

[0060] Figure 3 Shown in accordance with Figure 2 A known winding method of a stator winding;

[0061] Figure 4 The present invention shows a known winding method for a stator winding (winding system) of two multi-branch subsystems;

[0062] Figure 5 shows the winding pattern used for the stator;

[0063] Figure 6 Shown for following Figure 5 A first conductor guiding structure in a winding manner;

[0064] Figure 7 Shown for following Figure 5 A second conductor guiding structure in a winding manner;

[0065] Figure 8 Shown for following Figure 5 A third conductor guiding structure in a winding manner;

[0066] Fig. 9 A cross-sectional view along the axis of rotation is shown with Figure 4 A known stator with a winding pattern;

[0067] Fig.10 A cross-sectional view along the axis of rotation is shown with Figure 5 The stator has a winding method;

[0068] Fig.11 A three-dimensional diagram showing Fig.10 stator;

[0069] Fig.12 Shown in side view Fig.10 and 11 stator;

[0070] Fig.13 The view along the axis of rotation shows the Figures 10 to 12 stator;

[0071] Fig.14 Show about having according to Figure 4 a plurality of maps of a first operating mode of a motor of a stator winding;

[0072] Fig.15 Show about having according to Figure 4 a plurality of maps of a second operating mode of the electric machine of the stator winding;

[0073] Fig.16 Show about having according to Figure 5 a plurality of diagrams of a first operating mode of the electric machine of the stator winding; and

[0074] Fig.17 Show about having according to Figure 5 FIG. 1 is a diagram of a second operating mode of an electric machine of a stator winding. DETAILED DESCRIPTION

[0075] Figure 1 The drive system 32 is shown, which includes power electronics 35 and an electric machine 2. The power electronics 35 form a three-phase AC system 5, so that the stator 1 can be loaded with three branches 7, 8, 9 and a varying current 41. The stator 1 is fed with a voltage block from a PWM, resulting in a clocked, largely sinusoidal current 41.

[0076] Figure 2 Shown in accordance with Figure 1 The stator winding of the stator 1 is designed in a three-way star circuit, wherein a voltage supply 4 for the electric machine 2 of the three-way first subsystem 5 is realized by a first converter 33 of the power electronics 35, and the first subsystem comprises a first group 6 of branches 7, 8, 9. The stator winding is simplified to consist of a resistor 37 and an inductor 36 for each branch 7, 8, 9.

[0077] exist Figure 2 The dashed line shows that Figure 4 or Figure 5 The stator winding is wound in a winding manner. To this end, the power electronic device 35 includes two converters 33 and 34, namely a first converter 33 and a second converter 34. The voltage supply 4 for the three-way first subsystem 5 is realized by the first converter 33, and the first subsystem includes the branches 7, 8, and 9 of the first group 6. The voltage supply 4 for the three-way second subsystem 10 is correspondingly realized by the second converter 34, and the second subsystem includes the branches 12, 13, and 14 of the second group 11.

[0078] Figure 3 Shown in accordance with Figure 2 The stator winding is placed in the first slots 16. 48 first slots 16 are provided, wherein six conductors 22 are arranged in each first slot 16.

[0079] Figure 4The known winding method of the stator winding of the stator 1 for two multi-branch subsystems 5, 10 is shown. For this purpose, the power electronic device 35 comprises two converters 33, 34, namely a first converter 33 and a second converter 34 (see Figure 2 ). The voltage supply 4 for the three-way first subsystem 5 is realized by the first converter 33, and the first subsystem includes the branches 7, 8, and 9 of the first group 6. The voltage supply 4 for the three-way second subsystem 10 is correspondingly realized by the second converter 34, and the second subsystem includes the branches 12, 13, and 14 of the second group 11. That is, a double three-phase voltage supply 4 is realized as a whole. Pulse width modulation signals 38 and 39, that is, PWM signals 38 and 39, can be generated by the DC voltage intermediate circuit through the converters 33 and 34, wherein the first signal 38 of the first converter 33 and the second signal 39 of the second converter 34 (see Figures 14 to 17 ) can be generated in parallel with one another or offset in time (so-called PWM interleaving).

[0080] The stator winding is placed in the second slots 17. In this case, 48 second slots 17 are provided, wherein six conductors 22 are arranged in each second slot 17. Figure 3 The rules for placing the hairpin winding must be followed in particular, in order to ensure the same surface effect in the branches 7, 8, 9, 12, 13, 14 of the different subsystems 5, 10. and the same amplitude of the induced voltage. This results in a large overlap of the second slots 17, in which the branches 6, 7, 8 of the first group 6 and the branches 12, 13, 14 of the second group 11 are respectively arranged. Due to the large spatial overlap between the subsystems 5, 10, i.e. over all 48 second slots 17 and the resulting spatial proximity of the conductors 22 of the different groups 6, 11, the AC system is strongly inductively coupled.

[0081] Figure 5 The winding method for the stator 1 is shown; namely, the stator winding with two multi-branch subsystems 5, 10. Figure 4 For details, refer to the description of the power electronics 35 in particular.

[0082] The dual three-phase voltage supply device 4 supplies a three-branch first subsystem 5 with a first group 6 branch: a first branch 7, a second branch 8, and a third branch 9, and supplies a three-branch second subsystem 10 with a second group 11 branch: a fourth branch 12, a fifth branch 13, and a sixth branch 14. The stator 1 includes a cylindrical base body 15 with a plurality of slots 16, 17, which extend in an axial direction 18 and a radial direction 19 and are arranged side by side in a circumferential direction 20, and in this case, a tooth 21 is formed between the slots. In each slot 16, 17, a plurality of electrical conductors 22 are arranged, which are arranged in the slots 16, 17 as distributed windings. Each conductor 22 is respectively assigned to a branch 7, 8, 9, 12, 13, 14 and a subsystem 5, 10. In at least one first slot 16 of the stator 1, only one conductor 22 is arranged which is assigned to only one branch 7, 8, 9, 12, 13, 14 and system 5, 10, and in at least one second slot 17, at least two conductors 22 which are assigned to different branches 7, 8, 9, 12, 13, 14 of different groups 6, 11 are arranged (see also Fig.10 ).

[0083] The stator 1 comprises a cylindrical base body 15 which has grooves 16, 17, also referred to as slots, on an inner circumferential surface 48. The grooves 16, 17 extend in an axial direction 18 and in a radial direction 19 parallel to the rotation axis 3 of a rotor corresponding to the stator 1, which is located at Fig.10 The slots 16, 17 are not shown in the figure but are arranged inside the stator 1. The slots 16, 17 have a depth extending in the radial direction 19, a width extending in the circumferential direction 20 and a length extending in the axial direction 18. A tooth 21 is formed between every two slots 16, 17.

[0084] In the slots 16, 17, starting from the slot bottom 25 and along the radial direction 19, electrical conductors 22 are arranged one on top of another and electrically insulated from one another in six slot layers. The conductors 22 are electrically conductively connected to the branches 7, 8, 9, 12, 13, 14 of the subsystems 5, 10, respectively. The electrical conductors 22 are formed by hairpin structures or rods, which are arranged in the form of turns on the stator 1. Each turn consists of an outgoing wire and a return wire, which respectively represent the turn sides in two different slots 16, 17 and can consist of one conductor or a plurality of parallel-connected conductors. The application of current to the electrical conductors 22 generates a rotating field in a known manner, which interacts with the rotor field for driving the rotor.

[0085] The conductors 22 are arranged in the slots 16 , 17 in the manner of a distributed winding.

[0086] A plurality of first slots 16 arranged adjacent to one another form a first annular segment 23 of the stator 1 (here slots 7 to 24 and 31 to 48), and a plurality of second slots 17 arranged adjacent to one another form a second annular segment 24 (here slots 1 to 6 and 25 to 30). Only conductors 22 assigned to either the first group 6 or the second group 11 are arranged in the first slots 16 of the first annular segment 23. The shunts 7, 8, 9 of the first group 6 are arranged only inside one first annular segment 23 (here in slots 7 to 24). The shunts 12, 13, 14 of the second group 11 are arranged only inside the other first annular segment 23 (here in slots 31 to 48).

[0087] A second annular segment 24 having a second groove 17 is arranged between the two first annular segments 23. Three conductors 22 assigned to the first group 6 and three conductors 22 assigned to the second group 11 are arranged in each second groove 17 of the second annular segment 24. In each second groove 17 of the second annular segment 24 and starting from the groove bottom 25, conductors 22 assigned to different branches 7, 8, 9, 12, 13, 14 are arranged alternately one above the other.

[0088] A number of second slots 17 corresponding to the number of different groups 6 , 11 , namely two, are arranged next to one another in the circumferential direction 20 , wherein the two second slots 17 each have an identical arrangement of conductors 22 associated with different branches 7 , 8 , 9 , 12 , 13 , 14 .

[0089] A number of second grooves 17 corresponding to the number of different branch paths 7, 8, 9, 12, 13, 14 of all groups 6, 11, namely six, are arranged next to each other in the circumferential direction 20. That is, six second grooves 17 are arranged next to each other in each of the two second annular segments 24.

[0090] The stator 1 has two first annular segments 23 and two second annular segments 24 , wherein the number of first grooves 16 in the two first annular segments 23 is greater than the number of second grooves 17 in the two second annular segments 24 .

[0091] Thus, on the one hand, two first annular segments 23 are achieved in which the different subsystems 5, 10 do not overlap in space, and on the other hand, two second annular segments 24 are achieved in which the subsystems 5, 10 overlap in space. The overlapping region here extends over twice the six second slots 17. Thus, in the case of a stator 1 with 48 slots 16, 17, 36 slots 16, 17 are obtained that do not overlap between the two three-way subsystems 5, 10. Each subsystem 5, 10, which is controlled by a separate converter 33, 34, therefore has 18 slots 16, 17 in each case.

[0092] Figure 6 Shown for following Figure 5 1 , for an application with an intermediate circuit voltage of, for example, 800 volts. The conductor guiding structure of the first branch 7 of the first subsystem is shown. Starting from the coil start 26 and the first end side 28 of the stator 1, the conductor 22 first extends through the second slot 17 (here slot 4) to the second end side 29. By means of a second connection 31 arranged on the second end side 29, the conductor 22 extends in the region of the winding head along the circumferential direction 20 to the first slot 16 (here slot 9) and back to the first end side 28. By means of a first connection 30 arranged on the first end side 28, the conductor 22 extends in the region of the other winding head along the circumferential direction 20 to the second slot 17 (here slot 3) and back to the second end side 29. The conductor 22 thus extends through slots 3, 4, 9, 10, 15, 16, 21, 22, 27 and 28 to the coil end 27, which is connected to the slot 22 at the first end side 28. The routing of the conductor 22 through the slots 16 , 17 and on the stator 1 means that no complex return routing is necessary in the winding head.

[0093] Figure 7 Shown for following Figure 5 The second conductor-guiding structure of the embodiment of the present invention is wound in a manner similar to that of the embodiment of the present invention, for applications with an intermediate circuit voltage which is halved compared to the first conductor-guiding structure, ie, for example, 400 volts. Figure 6 Description.

[0094] In contrast to the first conductor guide structure, the number of turns in the conductor guide structure and thus the number of conductors 22 is adjusted here. However, the fundamental staggering of the conductors 22 remains unchanged. The overlapping areas of the different subsystems 5, 10 also remain unchanged.

[0095] Starting from the coil start 26 and the first end face 28 of the stator 1, the conductor 22 of the first branch 7 of the first subsystem 5 first extends through the second slot 17 (here slot 4) to the second end face 29. The conductor 22 extends in the region of the winding head along the circumferential direction 20 to the first slot 16 (here slot 9) and back to the first end face 28 via the second connection 31 provided on the second end face 29. The conductor 22 extends in the region of the further winding head along the circumferential direction 20 to the second slot 17 (here slot 3) and back to the second end face 29 via the first connection 30 provided on the first end face 28. The conductor 22 thus extends through the slots 3, 4, 9, 10, 15, 16, 21, 22, 27 and 28 to the coil end 27, which is connected to the slot 22 at the first end face 28. The routing of the conductor 22 through the slots 16, 17 and on the stator 1 means that no complex return routing is required in the winding head.

[0096] Figure 8Shown for following Figure 5 A third conductor guide structure in a wound manner is used for applications with an intermediate circuit voltage of, for example, 800 volts. Figure 6 and Figure 7 Description.

[0097] Here, the conductor guiding structure and the staggered mode of the conductor 22 are designed differently. Due to the change in the staggered mode, the occupation (or distribution) of the slot layer in the overlapping area (i.e. in the second slot 17) is also changed. Therefore, each individual conductor 22 or hairpin structure in the slot 16, 17 can be assigned to different slot layers. Depending on which hairpin structures are superimposed (which consecutive numbering is selected here), the voltage difference between the superimposed hairpin structures can also be influenced. That is, the voltage difference between the superimposed hairpin structures can be reduced here and thus, for example, the breakdown probability or the insulation load can be reduced.

[0098] Starting from the coil start 26 and the second end side 29 of the stator 1, the conductor 22 of the second branch 8 of the first subsystem 5 first extends through the first slot 16 (here the slot 20) to the first end side 28. The conductor 22 extends in the region of the winding head along the circumferential direction 20 to the first slot 16 (here the slot 26) and back to the second end side 29 via a first connection 31 arranged on the first end side 28. The conductor 22 extends in the region of the other winding head along the circumferential direction 20 to the first slot 16 (here the slot 20) and back to the first end side 28 via a second connection 31 arranged on the second end side 29. The conductor 22 thus extends through the slots 26, 25, 20, 19, 14, 13, 8, 7, 21 to the coil end 27, which is connected to the slot 1 at the second end side 29.

[0099] Fig. 9 The cross-sectional view along the rotation axis 3 shows the Figure 4 A known stator 1 of the winding method. Figure 4 Description.

[0100] The stator 1 comprises a cylindrical base body 15 having a plurality of second slots 17, which extend in an axial direction 18 and in a radial direction 19 and are arranged side by side in a circumferential direction 20, and in each case teeth 21 are formed between the slots. In each second slot 17, a plurality of electrical conductors 22 are arranged, which are arranged in the second slots 17 as distributed windings. Each conductor 22 is respectively assigned to a branch 7, 8, 9, 12, 13, 14 and a subsystem 5, 10. In each second slot 17, at least two conductors 22 of different branches 7, 8, 9, 12, 13, 14 of different groups 6, 11 are arranged. The second slots 17 extend in an axial direction 18 and in a radial direction 19 parallel to the rotation axis 3 of a rotor corresponding to the stator 1, which is arranged in a circumferential direction 20. Fig. 9 The second slots 17 are not shown in the figure, but are arranged inside the stator 1. The second slots 17 have a depth extending in the radial direction 19, a width extending in the circumferential direction 20, and a length extending in the axial direction 18. A tooth 21 is formed between every two second slots 17. In the second slots 17, starting from the slot bottom 25 and in the radial direction 18, electrical conductors 22 are arranged one above the other in six slot layers and are electrically insulated from one another.

[0101] The stator winding is inserted only in the second slots 17. 48 second slots 17 are provided, wherein six conductors 22 are arranged one on top of the other in the form of slot layers in each second slot 17. A large overlap region of the second slots 17 is formed (see arrows showing second annular segments 24), in which the branches 6, 7, 8 of the first group 6 and the branches 12, 13, 14 of the second group 11 are respectively arranged. Due to the large spatial overlap region between the subsystems 5, 10, i.e., over all 48 second slots 17, and the resulting spatial proximity of the conductors 22 of different groups 6, 11, the subsystems 5, 10 are strongly inductively coupled.

[0102] Fig.10 The cross-sectional view along the rotation axis 3 shows the Figure 5 The winding method of the stator 1. Reference about Figure 5 Description.

[0103] The stator 1 comprises a cylindrical base body 15, which has grooves 16, 17 on an inner circumferential surface 48. The grooves 16, 17 extend in an axial direction 18 and in a radial direction 19 parallel to the rotation axis 3 of a rotor corresponding to the stator 1, which is not shown here but is arranged inside the stator 1. The grooves 16, 17 have a depth extending in the radial direction 19, a width extending in the circumferential direction 20 and a length extending in the axial direction 18. A toothing 21 is formed between every two grooves 16, 17.

[0104] Fig.11 A three-dimensional diagram showing Fig.10 Stator 1. Fig.12 Shown in side view Fig.10 and Fig.11 Stator 1. Fig.13 The view along the rotation axis 3 shows the Figures 10 to 12 The winding method shown here corresponds to the stator 1 according to Figure 6 A first conductor-guiding structure for an application having an intermediate circuit voltage of 800 volts. Figures 5 to 10 Description.

[0105] Since the coils according to the proposed winding method extend only within the first annular section 23 of the respective group 6, 10 assigned to the branch 7, 8, 9, 12, 13, 14, the conductors 22 or the pin ends of the hairpin structure from the same slot position must overlap (twist) and contact each other in different directions in the circumferential direction 20. This results in different numbers of contact points 44 in the winding head in the radial direction 19 (in the present exemplary embodiment, 2 to 4 contact points 44).

[0106] Fig.14 Show about having according to Figure 4 4. In the upper figure, time 40 is shown on the horizontal axis and PWM signals 38, 39 are shown on the vertical axis. In this case, the first signal 38, i.e. the PWM period of the first branch 7 of the first group 6, and the second signal 39, i.e. the PWM period of the fourth branch 12 of the second group 10, are parallel to each other in time.

[0107] In the middle diagram, time 40 is plotted along the horizontal axis and current 41 of the respective branch 7, 8, 9 of the first group 6 is plotted along the vertical axis. Curve 43 shows the current 41 resulting in the respective branch 7, 8, 9 over time 40. The oscillation superimposed on the sinusoidal fundamental oscillation 43 is a current harmonic oscillation.

[0108] In the lower figure, the orders 45 of the current harmonic oscillations are plotted along the horizontal axis and the amplitudes 42 of the current harmonic oscillations are plotted along the vertical axis in order to realize the Fourier decomposition of the current 43. The amplitudes 42 marked with circles at specific orders 45 are current harmonic oscillations with frequent switching (lower orders 45) and current harmonic oscillations with twice the frequent switching (higher orders 45).

[0109] Fig.15 Show about having according to Figure 4 FIG. 2 is a diagram of a second operating mode of the motor 2 having a stator winding. Fig.14 Description.

[0110] In this Fig.14 In contrast, it can be seen in the upper figure that the PWM periods, i.e. the first signal 38 and the second signal 39, are each offset by one quarter of a period (PWM interleaving). The significantly more pronounced superimposed oscillations in the case of PWM interleaving, which can be seen in the middle figure, indicate a strong inductive coupling of the individual branches 6, 7, 8, 12, 13, 14 of the respective subsystems 5, 10. In the lower figure, it can be seen that the significantly higher amplitudes of the frequently switched and doubly frequently switched current harmonic oscillations. The amplitudes 42 marked with circles at certain orders are frequently switched current harmonic oscillations (lower order 45) and doubly frequently switched current harmonic oscillations (higher order 45).

[0111] Fig.14 and Fig.15 The disadvantages of the known winding method when independently controlling two subsystems with two converters 33, 34 in a shunt current are shown. Fig.15 ), higher current fluctuations or higher amplitudes of current harmonic oscillations (especially due to clocking) occur, which are undesirable and lead to additional losses. The additional losses are generated at various locations in the associated magnetic circuit (stator winding (current heat losses), in the electrical steel sheets, in the magnets (permanent-magnet excited synchronous motors), rotor windings (asynchronous motors), etc.).

[0112] Fig.16 Show about having according to Figure 5 FIG. 1 is a diagram of a first operating mode of the motor 2 of the stator winding. Fig.14 Description.

[0113] As in Fig.14 As can be seen in the upper figure, the PWM cycles, ie the first signal 38 and the second signal 39, are parallel to each other in time. Fig.14 Same operating point. It can be seen from the curve 43 in the middle diagram that superimposed oscillations are present only to a small extent. In the lower diagram, the amplitudes of the current harmonic oscillations caused by the clock control can hardly be recognized. The amplitudes 42 marked with circles at specific orders are the current harmonic oscillations with frequent switching (lower order 45) and the current harmonic oscillations with twice the switching frequency (higher order 45).

[0114] Fig.17 Show about having according to Figure 5 FIG. 2 is a diagram of a second operating mode of the motor 2 having a stator winding. Fig.15 Description.

[0115] As in Fig.15As can be seen in the upper figure, the PWM periods, ie the first signal 38 and the second signal 39, are shifted relative to each other by a quarter period (PWM staggering). Fig.15 Same operating point. As can be seen from the curve 43 in the middle diagram, superimposed oscillations are also present only to a small extent here. In the lower diagram, the amplitudes of the current harmonic oscillations caused by the clock control are barely recognizable. The amplitudes 42 marked with circles at certain orders are current harmonic oscillations with frequent switching (lower order 45) and current harmonic oscillations with twice the switching frequency (higher order 45).

[0116] Fig.16 and Fig.17 The advantages of the proposed winding method in the case of independent control of two subsystems 5, 10 with two converters 33, 34 in the branch current are shown. Fig.17 ), small current fluctuations and very small amplitudes of current harmonic oscillations (especially due to clock control) are generated. The current shape (see curve 43) differs only slightly from the desired sinusoidal shape, so that the additional losses due to current harmonic oscillations are significantly reduced.

[0117] List of Reference Numerals

[0118] 1 Stator

[0119] 2 Machines

[0120] 3 Rotation Axis

[0121] 4 Voltage supply device

[0122] 5. The first subsystem (AC system)

[0123] 6 Group 1

[0124] 7 First Branch

[0125] 8 Second Branch

[0126] 9 The Third Branch

[0127] 10 Second subsystem (AC system)

[0128] 11 Group 2

[0129] 12 Fourth Branch

[0130] 13 Fifth Branch

[0131] 14 Sixth Branch

[0132] 15 Matrix

[0133] 16 First Slot

[0134] 17 Second slot

[0135] 18 Axial direction

[0136] 19 Radial direction

[0137] 20 Circumferential direction

[0138] 21. Tooth

[0139] 22 Conductor

[0140] 23 First annular segment

[0141] 24 Second annular segment

[0142] 25 Slot bottom

[0143] 26 Coil start

[0144] 27 Coil terminal

[0145] 28 First end side

[0146] 29 Second end side

[0147] 30 First connection part

[0148] 31 Second connection

[0149] 32 Drive system

[0150] 33 First Converter

[0151] 34 Second converter

[0152] 35 Power Electronics

[0153] 36 Inductor

[0154] 37 Resistors

[0155] 38 First Signal

[0156] 39 Second Signal

[0157] 40 hours

[0158] 41 Current

[0159] 42 Amplitude

[0160] 43 Change curve

[0161] 44 Contact area

[0162] 45 Degree

Claims

1. A stator (1) of an electric machine (2), comprising a rotating shaft (3) and being used for at least a double three-phase voltage supply (4); wherein: The electric motor (2) has at least one three-way first subsystem (5) and a three-way second subsystem (10), wherein the first subsystem has a first group (6) of branches: a first branch (7), a second branch (8), and a third branch (9), and the second subsystem has a second group (11) of branches: a fourth branch (12), a fifth branch (13), and a sixth branch (14); wherein the stator (1) comprises at least one cylindrical base body (15) having a plurality of slots (16, 17), wherein the slots extend in an axial direction (18) and a radial direction (19) respectively and are arranged side by side in a circumferential direction (20), and wherein tooth portions (21) are formed between the slots respectively. ; wherein a plurality of electrical conductors (22) are arranged in each slot (16, 17), the electrical conductors being arranged in the slots (16, 17) as distributed windings; wherein each conductor (22) is respectively assigned to a branch (7, 8, 9, 12, 13, 14) and a subsystem (5, 10); wherein in at least one first slot (16) of the stator (1) only a conductor (22) assigned to only one branch (7, 8, 9, 12, 13, 14) of the subsystem (5, 10) is arranged, and wherein in at least one second slot (17) at least two conductors (22) assigned to different branches (7, 8, 9, 12, 13, 14) are arranged, A plurality of first grooves (16) arranged adjacent to one another form a first annular segment (23) of the stator (1), and a plurality of second grooves (17) arranged adjacent to one another form a second annular segment (24), In this case, only conductors (22) which are assigned to either the first group (6) or the second group (11) are arranged in the first groove (16) of the first annular segment (23). In this case, all first slots (16) of a conductor (22) of a group (6, 11) are arranged in a continuous first annular section (23).

2. The stator (1) according to claim 1, wherein: At least one conductor (22) assigned to the first group (6) and at least one conductor (22) assigned to the second group (11) are arranged in each second groove (17) of the second annular segment (24).

3. The stator (1) according to claim 1, wherein: Conductors (22) assigned to different branches (7, 8, 9, 12, 13, 14) are arranged at least partially alternately in each second groove (17) of the second annular segment (24) and starting from the groove bottom (25).

4. The stator (1) according to claim 1, wherein: In each second slot (17), the number of conductors (22) assigned to a specific branch (7, 8, 9, 12, 13, 14) is the same.

5. The stator (1) according to claim 1, wherein: A number of second slots (17) corresponding to the number of different groups (6, 11) are arranged side by side along a circumferential direction (20); the second slots (17) have an identical arrangement of conductors assigned to different branches (7, 8, 9, 12, 13, 14).

6. The stator (1) according to claim 1, wherein: The stator (1) has at least one first annular segment (23) and at least one second annular segment (24); wherein the number of first grooves (16) of the at least one first annular segment (23) is greater than the number of second grooves (17) of the at least one second annular segment (24).

7. The stator (1) according to claim 1, wherein: The conductor (22) extends through a plurality of slots (16, 17) between a coil start (26) and a coil end (27) and is arranged in at least one first slot (16) and one second slot (17).

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