DE102018111104A1 - Stand for an electric machine with six phase windings and electric machine - Google Patents

Abstract

The invention relates to a stator for an electric machine with n * 4 poles. The stator has a stator core with n * 4 * 3 grooves and teeth and a six-phase stator winding, which is arranged on the stator core through the grooves such that each phase winding has both poles of the first type (106a, 107a, 106c, 107c, 106e, 107e, 106g, 107g) formed to wrap the phase winding around a number of teeth corresponding to the ratio of pole pitch and groove pitch, as well as second type poles (106b, 106d, 106f, 106h) to form the phase winding a smaller number of teeth is wound, as well as third-type poles (107b, 107d, 107f, 107h), to the formation of which the phase winding is wound around a larger number of teeth having. Furthermore, the invention relates to an electric machine with a stator according to the invention.

Description

The present invention relates to a stator for an electric machine having six phase windings and an electric machine having such a stator. In particular, the invention is in the field of generators for motor vehicles.

State of the art

In the prior art electrical machines, in particular generators, with three electrical phase windings are known and widely used. In applications of electrical machines, which require less noise and / or less voltage ripple, electrical machines are often used which have five or six electrical phase windings and six or eight pole pairs.

For example, a stator core may be chosen for this purpose whose number of slots, i. the number of grooves formed therein through which the stator winding can pass corresponds to the product of the number of electrical phase windings or phases and the number of poles. For example, typically for a 16 pole (eight pole pair) electrical machine and six electrical phase windings, a 96 slot stator core is typically used to achieve symmetrical arrangement of the phase windings, low harmonic dispersion, and efficient operation of the electrical machine. This gives a hole number, i. one slot per pole and electrical phase, from one.

However, stator cores with such a high number of slots often have the disadvantage that the teeth between two adjacent grooves must be made very narrow and therefore stability losses must often be taken into account. In particular, the stator winding can often not be applied to a stator core with such a high number of slots by means of a Einziehverfahrens because due to the filigree teeth of the stator core does not have sufficient stability to withstand the mechanical stresses during the Einziehverfahrens can. For this reason, stands whose stator core has such a high number of slots often have to be wound with different types of manufacturing methods, which, however, often entail a much higher production outlay.

In the prior art solutions are known which try to solve this problem by reducing the number of slots. In the DE 103 27 689 A1 discloses an electric machine with eight pole pairs or 16 poles, which has a six-phase stator winding, which are formed as two by 30 ° el. To each other twisted systems and are arranged on a stator core with 48 slots. In other words, the disclosed electric machine has two phase winding groups each having three phase windings, the two phase winding groups being out of phase with each other by 30 ° el. The phase shift of the two phase winding groups is due to a different interconnection of the two phase winding groups by a phase winding group is connected as a triangle and the other phase winding group as a star. However, the phase windings of the two phase winding groups must be wound differently, so that they have different numbers of turns. If, in particular, the electrical voltages of the two phase winding groups coincide, the number of turns of the phase winding groups must be exactly the factor V3 differ, ie by a factor of about 1.73. However, this is usually not exactly feasible, which is why typically voltage differences between the two phase winding groups are unavoidable.

Another possibility for producing a six-phase stator or a six-phase stator winding comprising two three-phase phase winding groups is, for example, in the document EP 1 225 676 A1 disclosed. Here, too, differently shaped phase windings are used, with some phase windings having only poles, for the formation of which the phase winding is wound around a number of teeth that corresponds to the ratio of pole pitch and groove pitch (full pitch pattern), and other phase windings only Pole, to whose formation the phase winding is wound around a smaller number of teeth (English: short pitch pattern). Thus, different phase windings for the realization of the six-phase stator winding are also required for this purpose.

Disclosure of the invention

According to the invention, a stator for an electric machine with six phase windings and an electric machine with such a stator with the features of the independent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description. The electric machine can be designed as a generator, in particular for use in a motor vehicle, or as a motor.

The invention presents a possibility of a 2x3-phase distributed winding with a phase shift between the two three-phase Phase winding groups, with n * 4 poles in a stator core with only n * 4 * 3 grooves as commonly used for only three-phase windings. Thus, an identical lamination (for lamellae of the stator core) can be used, as it is intended for the three-phase machine with n * 4 poles. It is particularly advantageous because all six phase windings are wound similarly and thus have the same electrical and electromagnetic properties. The invention uses the measure that each phase winding both poles of the first kind, to the formation of which the phase winding is wound around a number of teeth, which corresponds to the ratio of pole pitch and groove pitch, as well as poles of the second kind, for their formation, the phase winding to a smaller number of teeth is wound, as well as third-type poles, to whose formation the phase winding is wound around a larger number of teeth has. Preferably, n = 3, ie 12 poles and 36 slots, or n = 4, ie 16 poles and 48 slots.

The invention offers the advantage that a stator for an electric machine with n * 4 poles and six electrical phase windings can be provided with particularly low production costs. It can be used in particular a stator core of a three-phase machine with n * 4 poles. Due to the small number of grooves, the stator core can be formed so stable that it withstands the mechanical stresses occurring during winding of the stator winding by means of a retraction process. The fact that the stator core is provided with only n * 4 * 3 grooves, the grooves can be made more stable and in particular less filigree than conventionally used for six-phase windings with n * 4 poles stator cores with n * 4 * 6 grooves.

Since, as mentioned, all the phase windings are wound similarly, they have the same effective number of conductors and are thus exposed to the same current load. As a result, the electrical voltage provided by the stator winding is particularly uniform. In other words, this is particularly advantageous because inhomogeneities can be avoided by the identically designed phase windings and the electrical voltage generated by the generator can be provided in a particularly uniform and / or homogeneous and / or low-fluctuation manner. Furthermore, this offers the advantage that the production cost can be simplified, since preferably no different winding procedures for the individual phase windings must be taken into account.

According to a preferred embodiment, the different poles of the phase windings are distributed over the circumference of the stator core so that exactly two phase windings run in each slot. In other words, the stator winding is designed as a two-layer winding. In this way, the grooves can be made particularly flat, which increases the strength of the stator core and simplifies winding. To form a phase winding, the winding wire can be passed one or more times through the groove.

Preferably, the six phase windings comprise two phase winding groups each having three phase windings, the phase windings of a phase winding group forming an identical series of types of poles. Thus, the phase windings of a phase winding group together generate a voltage having a homogeneous voltage characteristic. More preferably, the phase windings of a first of the two phase winding groups form an inverse sequence of types of poles of the second of the two phase winding groups. In this way, the demand for six similar windings can be realized with a maximum of 30 ° el. Displacement particularly easy. This offers the further advantage that the production costs for the stator winding can be reduced and that due to the symmetry and / or similarity of the phase winding groups inhomogeneities and / or voltage fluctuations can be avoided particularly effectively. Particularly preferably, the two phase winding groups can be arranged and interconnected in such a way that there is a phase shift of substantially 30 ° between the voltage curves of the two phase winding groups (eg with a deviation of at most 5 °, preferably at most 2.5 °), which is especially true for the operation of a generator of a motor vehicle and in particular for six-phase generators is particularly advantageous.

Preferably, each phase winding has n distributed over the circumference of pole groups comprising two poles of the first kind, a pole of the second kind and a pole of the third kind. This offers the advantage that the individual phase windings can be designed such that a suitable arrangement of the phase windings on the stator core with n * 4 * 3 grooves is made possible and yet all six phase windings can be made identical, in particular if each pole group consists of four adjacent poles consists. Accordingly, a 16-pole phase winding has four such pole groups distributed circumferentially and a 12-pole phase winding has three such pole groups distributed circumferentially.

Preferably, two poles of the first type are always immediately adjacent in each phase winding. Also preferably always a pole of the second kind and a pole of the third kind are immediately adjacent. On In this way, the grooves can be used optimally for a n * 4-pole phase winding.

An arrangement which can be produced in a particularly simple manner is obtained if, in each phase winding, in each case two poles of the same type opposite to the circumference also have the same polarity.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

The invention is schematically illustrated by means of an embodiment in the drawings and will be described below with reference to the drawings.

list of figures

• 1 shows a winding scheme for a stator winding according to a preferred embodiment with six phase windings.
• 2 shows an enlarged view of a phase winding, which also in 1 already shown.
• 3A and 3B show electrical circuits for interconnecting the six phase windings according to preferred embodiments.

Embodiment of the invention

1 shows a winding scheme 100 for a stator winding of an electric machine with n * 4 = 16 poles (n = 4) according to a preferred embodiment of the invention for a stator core with n * 4 * 3 = 48 slots and 48 teeth. The slot pitch is thus mechanically 2π / 48 (7.5 °) and electrically p * 2π / 48 (60 °) with pole pair number p = 2 * n. As can be seen, it is a distributed winding.

The stator winding consists of six phase windings U . V . W . X . Y . Z in the 48 Grooves of the stator core are inserted. In this case, all 48 slots of the stator core are listed in tabular form and consecutively numbered and represented symbolically on the basis of the horizontally extending lines 102. Further, in the table 104 shown adjacent, the assignments of the individual grooves with the winding wires and electrical conductors of the phase windings and the direction of the respective winding wires in the corresponding groove are shown. To form a phase winding, the winding wire can be passed through the groove one or more times. Several times can be achieved, for example, by winding a plurality of winding wires in parallel and at the same time, or by winding a winding wire around the stator core several times, thus reaching the same grooves several times. The value means 1 in table 104 that the winding wire (s) extend through the groove along a first direction and the value -1 that the winding wire (s) is opposite to the first direction through the groove.

In the tabular representation, the arrangements of the winding wires of the phase windings U . V . W . X . Y and Z displayed side by side, although these are of course in the grooves one above the other in reality. As in the winding scheme 100 and in Table 104, each of the slots is covered with winding wires from two phase windings. Accordingly, the winding scheme shown is a two-layer winding.

It can be seen that all the phase windings U to Z are similarly wound, although the windings X . Y and Z are wound in the opposite direction than the windings U . V and W , The phase windings U - W thus form a first phase winding group and the phase windings X - Z form a second phase winding group.

The winding scheme will now be based on the phase winding X explained in more detail. The phase winding has 16 (n * 4) poles, the oBdA for illustration with " N "( 106a to 106 h) and " S "( 107a to 107h) are designated. The pole pitch is thus mechanically 2π / 16 (22.5 °) and electrically p * 2π / 16 (180 °). The poles are formed by winding the phase winding around a number of teeth. It can be seen that the number is not the same for all poles, but rather that poles of the first kind, to whose formation the phase winding is wound around a number of teeth, the ratio 3 (3 teeth corresponds mechanically 22.5 °, electrically 180 °) from pole pitch and groove pitch corresponds to ("full pitch"), poles of the second kind, to whose formation the phase winding is wound around a smaller number of 2 teeth ("short pitch") (2 teeth correspond mechanically 15 °, electrically 120 °), and poles of the third type, to whose formation the phase winding is wound around a larger number of 4 teeth ("long pitch") (4 teeth correspond mechanically 30 °, electrically 240 °) , exist. Two opposite poles of the same kind at the circumference each have the same polarity, ie a = e, b = f, c = g, d = h.

It can be seen that in the present example, the N poles only from Poland first type and Of the second kind, whereas the S-poles are formed only of first-kind poles and third-kind poles.

It can also be seen that the phase windings X . Y . Z form the second phase winding group an identical sequence of types of poles, ie in the present example oBdA 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3. Mit In other words, these phase windings each have n = 4 pole groups of two poles of the first kind, a pole of the second kind, and a pole of the third kind, these four poles being adjacent.

At the same time it can be seen that the phase windings U . V . W the first phase winding group to form a reverse sequence, ie in the present example oBdA 2, 1, 1, 3, 2, 1, 1, 3, 2, 1, 1, 3, but also each n = 4 pole groups of two poles of the first kind , a pole of the second kind and a pole of the third kind, these four poles being adjacent.

The phase windings Y and Z are similar and running in the same direction as the phase winding X formed, but by eight grooves ( Y ) or 16 grooves ( Z ) to the phase winding X added. Also the phase windings U . V and W are similar to the phase winding X trained, but these run in the opposite direction, whereby the phase windings U . V and W each phase-shifted or offset by twelve grooves to each other. The two phase winding groups are thereby shifted by about 30 ° el. To each other.

This winding arrangement according to the preferred embodiment is characterized in particular by the fact that it can be wound in a particularly simple manner and the stator can thus be produced in a particularly cost-effective manner. In particular, such a stator winding can be arranged on the stator core by means of a pull-in method, since the stator core can be provided with n * 3 * 4 = 48 teeth with a sufficient mechanical resistance in order to be able to withstand this method.

A stator with a stator winding according to the first preferred embodiment therefore preferably has a number of slots N = n * 3 * 4 = 48, a pole number 2p = 16 and, a phase number m = 6. A stator realized in this way could achieve a winding factor of 90.1%, a harmonic dispersion of 10.6% and a phase shift between the phase winding groups of φ = 27.8 °. The deviation from a particularly preferred phase shift of 30 ° is therefore only 2.2 °. However, this slight deviation from the desired or preferred phase shift of 30 ° does not represent a problem and / or a disadvantage in the operation of the stator. The winding factor of 90.1% can under certain circumstances lead to a slight tilting of the characteristic curve.

The winding scheme shown was based on a pull-in winding. The individual phase windings can be realized both as a wave winding and as a reverse wave.

2 shows an enlarged view of the phase winding U, which also in 1 already shown, with the actual guidance around the teeth.

The 3A and 3B show electrical machines 400 according to preferred embodiments, with a foreign-excited runner 401 and a stand as described above. The stand is with a rectifier 402 electrically connected, in 3A the phase windings U . V . W respectively. X . Y . Z in a double star connection and in 3B are connected in a double delta circuit.

The electric machines and / or stands according to preferred embodiments of the invention can be connected to electrical circuits for rectification, without special requirements are placed on the electrical circuits, which go beyond the requirements for connecting rectifiers with conventional electric machines or stands would. Thus, a stand or an electric machine according to a preferred embodiment of the invention can be incorporated into conventional circuits or systems, preferably without the need for elaborate design changes and / or adjustments are required.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10327689 A1 [0005]
• EP 1225676 A1 [0006]

Claims (12)

Stand for an electric machine with n * 4 poles, comprising: a stator core with n * 4 * 3 slots (102) and n * 4 * 3 teeth; - A stator winding comprising six phase windings (U, V, W, X, Y, Z), which is arranged through the grooves (102) extending on the stator core, that each phase winding both poles of the first kind (106a, 107a, 106c, 107c , 106e, 107e, 106g, 107g), to the formation of which the phase winding is wound around a number of teeth corresponding to the ratio of pole pitch and groove pitch, as well as poles of the second kind (106b, 106d, 106f, 106h) for their formation the phase winding is wound around a smaller number of teeth, as well as third type poles (107b, 107d, 107f, 107h), to form the phase winding is wound around a larger number of teeth has. Stand after Claim 1 where n = 3 or n = 4. Stand after Claim 1 or 2 wherein the six phase windings (U, V, W, X, Y, Z) comprise two phase winding groups each having three phase windings, the phase windings of a phase winding group forming an identical series of types of poles. Stand after Claim 3 wherein the phase windings of a first of the two phase winding groups form a series of types of poles reversed to a second of the two phase winding groups. Stand after Claim 3 or 4 , wherein the two phase winding groups are shifted by (30 ± 5) ° el. Stand according to one of the preceding claims, wherein each phase winding (U, V, W, X, Y, Z) has n pole groups comprising two poles of the first kind, a pole of the second kind and a pole of the third kind. Stand after Claim 6 , wherein each pole group consists of four adjacent poles. Stand according to one of the preceding claims, wherein in each phase winding (U, V, W, X, Y, Z) always two poles of the first kind are immediately adjacent. Stand according to one of the preceding claims, wherein in each phase winding (U, V, W, X, Y, Z) always a pole of the second kind and a pole of the third kind are immediately adjacent. Stand according to one of the preceding claims, wherein the phase windings (U, V, W, X, Y, Z) are wound in the Einziehverfahren. An electric machine (400) comprising a rotor (401) and a stator according to any one of the preceding claims. Electric machine according to Claim 11 which is designed as a generator.

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