WO2021250162A1

WO2021250162A1 - Stator for an electric machine, and electric machine

Info

Publication number: WO2021250162A1
Application number: PCT/EP2021/065594
Authority: WO
Inventors: Roland BUOL; Martin STÖCK
Original assignee: Jheeco E-Drive Ag
Priority date: 2020-06-10
Filing date: 2021-06-10
Publication date: 2021-12-16
Also published as: DE102020115521A1; EP4165754A1

Abstract

The present invention relates to a stator (R) for an electric machine, wherein the stator (S) has a stator core (1) with at least one groove (13) for receiving electrical conductors (3), wherein electrical conductors (3) are received at at least three positions (3a, 3b, 3c). The invention also relates to an electric machine, in particular an electric motor, comprising a stator (R) and a stator (S), characterised by a stator (R) according to at least one of the preceding claims.

Description

Stator for an electrical machine, as well as an electrical machine

The present invention relates to a stator for an electrical machine according to the preamble of claim 1, as well as an electrical machine, in particular an electric motor, according to the preamble of claim 9.

A stator for an electrical machine essentially comprises a stator package with a number of slots running in the axial direction, whereby the slots can run straight or at an angle to the axial direction, as well as windings received in each slot, which consist of one or more parallel wires, solid copper rod ( Hairpin or I-pin) or a shaped strand (consisting of several individual wires connected in parallel).

When making the turns, either one or more parallel wires are wound onto a bobbin and pulled into the slot (pull-in winding) or conductors are inserted into the slots (plug-in winding), which are then interconnected to form a winding. Hairpin, I-pin and shaped strands are examples of plug-in windings. With plug-in windings, several conductors are usually inserted one above the other in a slot, this number is called the number of conductors. In the case of pull-in windings (or windings with individual wires), the term “conductor” is used when conductors consisting of one or more turns are produced as a coil and inserted into the slot as such.

Stators according to the prior art generally have a certain number of slots per pole and phase (called number of holes).

The number of turns per phase is decisive for the voltage level of the machine, which can be calculated from the number of holes, the number of poles and the number of conductors per slot (number of conductors). The voltage level is often given by the voltage source of the application. The number of poles is given by the maximum speed and the maximum converter frequency of the application. It is therefore clear that for a given voltage level and a given number of poles, a variation in the number of holes must be compensated for by a variation in the number of conductors.

With a given number of poles, a high number of holes means a high number of slots and vice versa. Variants with a high number of stator slots result in smaller slot surfaces with the same size. If the insulation thickness remains the same, the area fraction of the insulation per slot area increases sharply.

Variants with a low number of stator slots with the same size generally have higher scatter figures. This results in higher leakage inductances and thus a deterioration in the efficiency and the power factor. In addition, the ratio of the number of stator slots to the number of rotor slots must be carefully selected in order to achieve a minimum level of noise.

Due to the diverse influencing factors of the number of stator slots on the electric motor characteristics, the greatest possible flexibility is required when choosing the number of slots.

In the case of plug-in windings, the individual conductors in the winding head are usually bent and connected to one another, for example welded. So that these do not collide geometrically, the innermost conductor of the first slot of a phase must be connected to the second innermost conductor of the first slot of the same phase, which is, however, offset by one pole. For this reason, plug-in windings with bent conductors in the end winding are always implemented with an even number of conductors (2, 4, 6, 8, ...). It is therefore particularly difficult to achieve the desired number of phase turns in principle, particularly with plug-in windings, without making the above-mentioned compromises in terms of the number of stator slots.

This is where the present invention comes into play and has set itself the task of proposing an improved stator which also allows an uneven number of conductors in order to achieve a finer adjustment of the number of phase turns.

According to the invention, this object is achieved by a stator with the characterizing features of claim 1. Because an odd number of electrical conductors (1, 3, 5, 7, ...) are inserted into the grooves, the disadvantages outlined above can be reduced. This is particularly important for the plug-in winding. The arrangement of, for example, three electrical conductors per groove enables the grooves to be provided to be reduced to a level that enables a balanced relationship between low insulation requirements, low leakage inductances, low noise generation and high efficiency. More beneficial Refinements of the proposed invention emerge in particular from the features of the subclaims. The objects or features of the various claims can in principle be combined with one another as desired.

In this case, one conductor, as a phase conductor, is preferably passed through a first groove without electrical interruption and then passed through further grooves in sequence and connected at its ends to the phase assigned to it. The phase conductors can be designed with a continuous winding or with a corresponding electrical connection to form a continuous electrical winding.

It is particularly preferable to electrically connect the conductors to one another in the respective grooves via retaining webs. The interconnection rings allow a free definition of which conductors can be connected to which adjacent conductors and / or to which phase.

If one or more phase conductors are circulated several times, the phase conductors are arranged at corresponding positions in the grooves. In this case, phase conductors that are all connected to one phase or phase conductors that are connected to different phases can be arranged in one and the same groove at the positions.

In an advantageous embodiment of the invention it can be provided that an odd number of conductors is received in the at least one groove. What is meant is a number of n = 1, 3, 5, 7, ..., therefore at least one conductor per slot and the following odd numbers.

In a further advantageous embodiment of the invention it can be provided that between 36 and 60 slots, preferably 48 slots, for receiving the conductors are arranged in the stator core. With this constellation, consisting of 48 slots and preferably 3 conductors per slot, there is a particularly well-balanced relationship between low insulation requirements, low leakage inductances, low noise generation and high efficiency.

In a further advantageous embodiment of the invention it can be provided that the grooves for receiving the conductors are coaxial with the longitudinal axis of the stator core are arranged. The grooves for receiving the conductors thus preferably run axially in the stator core. Alternatively, however, it is conceivable and possible to arrange the grooves in the stator core in a helical manner around the longitudinal axis of the stator core, which can be referred to by the term inclined stator.

In a simple winding scheme, there are only conductors with the same phase in one slot - this is called a single-layer winding. However, one or more conductors of one phase and one or more conductors of another phase can also be located in a groove.

With a two-layer winding, the conductors are divided into two groups (an outer and an inner group). The outer group is offset from the inner group by one or more grooves. With an even number of conductors, the separation can be designed so that both groups have the same number of conductors. If there are uneven numbers of conductors, the principle is that the numbers of conductors in the two groups are not identical.

With a three-layer winding, the conductors are divided into three groups (inner, middle, outer group). The number of conductors can be greater than or equal to 3) The three groups are each offset from one another by one or more grooves in the same direction of rotation.

With an N-layer winding, the M conductors are divided into N groups (where M is greater than or equal to N). The N groups are each offset from one another by one or more grooves in the same direction of rotation.

In a further advantageous embodiment of the invention it can be provided that the first conductors form a first layer which are arranged in a first radius from the longitudinal axis, the second conductors forming a second layer which are arranged in a second radius around the longitudinal axis, wherein the third conductors form a third layer, which are arranged in a third radius around the longitudinal axis, with conductors arranged next to one another in a groove in the circumferential direction being connected to a first phase of a current and / or voltage source, with four others next to one another in the circumferential direction in a groove arranged conductors are connected to a second phase of a current and / or voltage source, with four more in Circumferential direction side by side in a groove conductors are connected to a third phase of a current and / or voltage source, the layers being in phase or at least one layer out of phase with another layer, in particular out of phase around a groove or a conductor. Via the offset, the field exciter curve can be adapted optimally or, more precisely, as close as possible to a sinus curve. In-phase here is to be understood as meaning that two or more conductors are connected in a slot with the same phase, for example the three phases U, V or W. Phase offset means that adjacent conductors in a slot are connected to different phases, for example phases U, V, W.

It is conceivable and possible to use the solution according to the invention on a multi-phase machine, in particular with, for example, 6 or 9 phases.

In a further advantageous embodiment of the invention it can be provided that the electrical conductor is designed as a wire, hairpin, I-pin or shaped strand.

The interconnection of the individual conductors is advantageous because of the odd number of conductors / slot, for example through the use of a tier winding system. In particular, if the winding system is to be represented as a classic pull-in winding, a connection ring is preferably used, with which the corresponding conductors are electrically connected to one another as required. This variant is particularly preferable if the winding system is shown as a wave winding, for example in the form of a classic hairpin, I-pin or shaped strand winding. With a wave winding, the phase conductors are led from one slot into the next without electrical interruption and the respective phase conductors are connected to the phases at their ends. The electrical connection can be formed by connecting hair pins of the respective grooves to one another or by a continuous conductor, for example a shaped strand, which is passed through the corresponding grooves.

With the asynchronous machine, a higher number of layers allows better adaptation of the field exciter curve to the desired sine and with the synchronous machine a reduction in the ripple torques. Both machine types achieve increased efficiency by optimizing the winding factor while minimizing the machine-related additional losses (pulsation losses).

Further features and advantages of the present invention will become clear on the basis of the following description of preferred exemplary embodiments with reference to the accompanying figures. Show in it

1 shows a schematic illustration of a stator according to the invention with a rotor shaft in a perspective illustration;

2 shows a stator according to the invention in a sectional illustration;

3 shows a stator according to the invention in a sectional illustration;

4 shows a stator according to the invention in a sectional illustration;

FIG. 5 shows a field exciter curve for a stator according to FIG. 2; FIG.

6 shows a field exciter curve for a stator according to FIG. 3;

7 shows a field exciter curve for a stator according to FIG. 4;

8 shows an electrical machine according to the invention in a perspective view

Depiction.

The following reference symbols are used in the figures:

R rotor

S stator

L Longitudinal axis r _a inner radius of position 3a r _b inner radius of position 3b r _c inner radius of position 3c

1 stator package 2 rotor shaft

3 electrical conductors

3a, 3b, 3c position of the ladder

11 stator disc

12 - free -

13 groove

14 Current or voltage source

I, II, III phase conductor

U, V, W phase

Reference is first made to FIGS. 1 and 2.

A stator S according to the invention essentially comprises a stator core. As a rule, the stator core 1 consists of a number of stator disks 11, preferably made of sheet metal, which are arranged axially one behind the other. As a rule, the stator core 1 is equipped with an opening through which a rotor shaft 2 can be inserted. The rotor shaft 2 is mounted with respect to the stator core 1 for the transmission of torques. The stator S or the stator core 1 has a longitudinal axis which is identified by the reference character L.

The stator package 1 is also equipped with a number of grooves 13 for receiving electrical conductors 3. The grooves run in particular in the axial direction and / or are arranged coaxially to the longitudinal axis L. The grooves 13 are preferably designed as channels. To designate the respective groove, the grooves 13 are designated with an index, that is, starting at, for example, 0 ° as 13.1 to 13.x. The following examples show stator packs with 48 slots, i.e. slots 13.1, 13.2 to 13.48. At least three or an odd number greater than 1 of conductors 3 are accommodated in each groove 13, ie for example three, five, seven, nine, etc. However, exactly three conductors 3 are preferred in the positions 3a, 3b, 3c in the groove 13 brought in.

The conductors 3 running axially per groove 13 are arranged one above the other in the radial direction. There is a radial sequence of conductors 3 (from inside to outside) at positions 3a, 3b and 3c for each groove13. An arrangement of three superposed conductors 3 per groove can also be addressed as a three-layer system.

Each conductor 3 is at least indirectly connected to a phase of a current or voltage source 14 with the phases U, V, W. The phase conductor I is connected to the phase U, the phase conductor II to the phase V and the phase conductor III to the phase W, as is illustrated schematically in FIG.

An example of a stator according to the invention is shown in FIG.

It is a 3-layer / 1-layer winding system.

The arrangement of conductors and phases in the grooves is as follows:

Four grooves 13.1, 13.2, 13.3 and 13.4 are each occupied with phase conductors I at positions 3a, 3b and 3c, all of the conductors being connected to the first phase U. Four further grooves 13.5, 13.6, 13.7 and 13.8 in the circumferential direction are each occupied with phase conductors II at positions 3a, 3b and 3c, all of the conductors being connected to the second phase V.

Four further grooves 13.9, 13.10, 13.11 and 13.12 in the circumferential direction are each occupied with phase conductors II at positions 3a, 3b and 3c, all of the conductors being connected to the third phase W.

The pattern sketched above continues clockwise in the circumferential direction three more times, so there is a total of four times over the circumference with 48 grooves.

The pattern outlined above can also be described by the offset with regard to the layers formed by the conductors. The inner conductors thus form a first layer at position 3a, the next conductor in the radial direction at position 3b a second layer and the external conductors in position 3c a third layer. The layers have corresponding inner radii r _a , r _b and r _c in relation to the longitudinal axis L, which are preferably different per layer.

In the example outlined here, each layer consists of a sequence of four conductors each with a phase conductor, i.e. four times at positions 3a and 3b and 3c one conductor I with phase U, and then one conductor II with phase V and each a conductor III connected to phase W. With the present constellation of 48 ladders per layer, the sequence is repeated three more times.

In the embodiment shown in FIG. 2, no offset is provided between the layers, so that the same phases are always included in the grooves.

Another example of a stator according to the invention is shown in FIG.

It is a 3-layer 12-layer winding system.

The arrangement of conductors and phases in the grooves is as follows:

Two grooves 13.1 and 13.2 are each occupied with phase conductors I at positions 3a, 3b and 3c, all of the conductors being connected to the first phase U.

Two further clockwise slots 13.3 and 13.4 are each occupied with conductors at positions 3a, 3b and 3c, the inner conductor at position 3a and the middle conductor at position 3b as phase conductor I with the first phase U and the outer conductor at position 3c are connected to the second phase V as phase conductor II.

Two further clockwise slots 13.5 and 13.6 are each occupied with the phase conductors II at positions 3a, 3b and 3c, with all conductors being connected to the second phase V.

Two further clockwise slots 13.7 and 13.8 are each occupied with conductors at positions 3a, 3b and 3c, the inner conductor at position 3a and middle conductor at position 3b as phase conductor II with the second phase V and the outer conductor at position 3c are connected to the third phase W as phase conductor III. Two further clockwise slots 13.9 and 13.10 are each occupied with phase conductors III at positions 3a, 3b and 3c, all of the conductors being connected to the third phase W.

Two further clockwise slots 13.11 and 13.12 are each occupied with conductors at positions 3a, 3b and 3c, the inner conductor at position 3a and the middle conductor at position 3b as phase conductor III with the third phase W and the outer conductor at position 3c as phase conductor I are connected to the first phase U.

The pattern outlined above can also be described by the offset with regard to the layers formed by the conductors. With regard to the definition of the layers, reference can be made to the statements made above.

In contrast to the embodiment according to FIG. 2, in a further embodiment described here, only the first layer at position 3a and the second layer at position 3b are not offset, i.e. in phase in each groove. However, the third layer at position 3c, i.e. the outer layer, is offset by two grooves, here counterclockwise, with respect to the first or second layer.

Another example of a stator according to the invention is shown in FIG.

It is a 3-layer 13-layer winding system.

The arrangement of conductors and phases in the grooves is as follows:

A next clockwise slot 13.3 is occupied by conductors at positions 3a, 3b and 3c, the inner conductor at position 3a and the middle conductor at position 3b as phase conductor I with the first phase U and the outer conductor at position 3c are connected to the second phase V as phase conductor II. A next clockwise slot 13.4 is occupied with conductors at positions 3a, 3b and 3c, the inner conductor 3a as phase conductor I with the first phase U and the middle conductor with position 3b and the outer conductor with position 3c as Phase conductor II are connected to the second phase V.

Two further clockwise grooves 13.5 and 13.6 are each occupied with phase conductors II at positions 3a, 3b and 3c, all of the conductors being connected to the second phase V.

A next clockwise slot 13.7 is occupied with conductors at positions 3a, 3b and 3c, the inner conductor at position 3a and the middle conductor at position 3b as phase conductor II with the second phase V and the outer conductor at position 3c the third phase W are connected.

A next clockwise slot 13.8 is occupied with conductors at positions 3a, 3b and 3c, the inner conductor at position 3a as phase conductor II with the second phase V and the middle conductor at position 3b and the outer conductor at position 3c as Phase conductor III are connected to the third phase W.

Two further clockwise grooves 13.9 and 13.10 are each occupied with phase conductors III at positions 3a to 3c, with all conductors being occupied with the third phase W.

A next clockwise slot 13.11 is occupied by conductors at positions 3a to 3c, the inner conductor at position 3a and middle conductor at position 3b as phase conductor III with third phase W and the outer conductor at position 3c as phase conductor I. the first phase U are connected.

A next clockwise slot 13.12 is occupied by conductors at positions 3a to 3c, the inner conductor at position 3a as phase conductor III with third phase W and the middle conductor at position 3b and the outer conductor at position 3c as phase conductor I. are connected to the first phase U.

The pattern sketched above continues clockwise in the circumferential direction three more times, so there is a total of four times over the circumference with 48 grooves. The pattern outlined above can also be described by the offset with regard to the layers formed by the conductors. With regard to the definition of the layers, reference can be made to the statements made above.

In contrast to the embodiment according to FIG. 2, the second layer is offset by one groove from the first layer, and the third layer is offset from the first layer by two grooves and the third layer is offset from the second layer by one groove.

The electrical conductor can be designed as a simple wire, hairpin, I-pin or shaped strand.

The interconnection of the individual conductors takes place, in particular because of the odd number of conductors / slot, for example through the use of a tier winding system, in particular if the winding system is built as a classic pull-in winding and / or with the help of a connection ring, in particular if the winding system is designed as a wave winding (classic Hairpin, I-Pin or molded stranded wire winding) is built. With a wave winding, the phase conductors are led from one slot into the next without electrical interruption and the respective phase conductors are connected to the phases at their ends. The electrical connection can be formed by connecting hair pins of the respective grooves to one another or by a continuous conductor, for example a shaped strand, which is passed through the corresponding grooves.

A higher number of layers allows a better adaptation of the field exciter curve to the desired sine in the asynchronous machine and a reduction of the ripple moments in the synchronous machine. Both machine types achieve increased levels of efficiency by optimizing the winding factor while at the same time minimizing the machine-related additional losses (pulsation losses).

In FIGS. 5 to 7, the mode of operation of several layers and corresponding arrangements of the conductors is illustrated. In FIG. 5, the field exciter curve for a 1-layer winding according to FIG. 2 is illustrated. In FIG. 6, the field exciter curve for a 2-layer winding is shown in accordance with FIG. 3 illustrated. In FIG. 7, the field exciter curve for a 3-layer winding according to FIG. 4 is illustrated.

Features and details that are described in connection with a method naturally also apply in connection with the device according to the invention and vice versa, so that with regard to the disclosure of the individual aspects of the invention, mutual reference is or can always be made. In addition, an optionally described method according to the invention can be carried out with the device according to the invention.

Claims

Expectations

1. Stator (S) for an electrical machine, the stator having a stator package (1) with at least one groove (13) for receiving electrical conductors (3), characterized in that in the at least one groove (13) at least three positions (3a, 3b, 3c) electrical conductors (3) are added.

2. Stator according to claim 1, characterized in that an odd number of conductors (3), in particular three conductors, is received in the at least one groove (13).

3. Stator according to claim 1, characterized in that in the at least one groove (13) an odd number of conductors (3) is received, which are combined to form one or more layers.

4. Stator according to claim 1, characterized in that an odd number of conductors (3) is received in the at least one groove (13), the stator having the same number of layers as conductors.

5. Stator according to at least one of the preceding claims, characterized in that between 36 and 60 slots (13), preferably 48 slots (13), for receiving the conductors (3) are arranged in the stator core.

6. Stator according to at least one of the preceding claims, characterized in that the first of the conductors (3) at the respective position (3a) form a first layer which are arranged in a first inner radius (r _a ) around the longitudinal axis, the second of the conductors (3) at the respective position (3b) form a second layer which are arranged in a second inner radius (r _b ) around the longitudinal axis, the third of the conductors (3) having a third at the respective position (3c) Form layers which are arranged in a third inner radius (r _c ) around the longitudinal axis, with at least four conductors arranged next to one another in the circumferential direction being connected to a first phase (U) of a current and / or voltage source, with four others arranged next to one another in the circumferential direction Conductors are connected to a second phase (V) of a current and / or voltage source, with four more conductors arranged next to one another in the circumferential direction are connected to a third phase (W) of a current and / or voltage source, wherein

- The layers are in phase or at least one layer is phase-shifted to another layer, in particular by a groove (13) or a position (3a, 3b, 3c) phase-shifted.

7. Stator according to at least one of the preceding claims, characterized in that the electrical conductor (3) is designed as a wire, hairpin, I-pin or shaped strand.

8. Stator according to at least one of the preceding claims, characterized in that the interconnection of the conductors takes place through the use of a tier winding system and / or at least one interconnection ring.

9. Electrical machine, in particular an electric motor, comprising a stator (S) and a rotor (R), characterized by a stator (S) according to at least one of the preceding claims.