EP2030305A1

EP2030305A1 - Alternator for motor vehicles

Info

Publication number: EP2030305A1
Application number: EP07729841A
Authority: EP
Inventors: Kurt Reutlinger; Gert Wolf; Alexander Shendi
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-06-07
Filing date: 2007-06-04
Publication date: 2009-03-04
Also published as: US8354770B2; JP2009540781A; US20100156230A1; JP5558813B2; CN101467332A; WO2007141230A1; DE102006026402A1

Abstract

An alternator is proposed for motor vehicles, having a rotor (20) whose poles (32) are in the form of claw-type poles. In order to improve the design options for the stator of the machine, its polyphase winding is in the form of a fractional-slot winding, thus creating a large number of additional options in particular for selection of the number of slots (N), thus not only considerably simplifying and reducing the cost of manufacture, but also at the same time making it possible to improve the electrical characteristics.

Description

description

Alternator for motor vehicles

State of the art

The invention relates to an alternator for motor vehicles, as it is known for example from DE 31 41 153 Al. This has an originally designed as a flat package laminated core with a three-phase stator winding, in which of the as

Claw poles trained rotor poles a circulating with the rotor magnetic field is induced. Such generators have windings with payloads which are an integer multiple of the number of poles and the number of phases, in particular three-phase generators with 12 poles and 3 phases and a number of 36 are useful. Furthermore, three-phase generators in 16-pole execution as generators for motor vehicles are known with 48 grooves. The number of holes q of this machine, which is the number of slots N, divided by the number of poles 2p and the phase number m, is an integer and has the value 1 in the aforementioned case.

Generators with two- or three-hole windings are also known. A three-phase

Two-hole winding with 12 poles has 72 slots, a three-phase three-hole winding 108 slots. A three-phase generator in 16-pole design then has 48 slots for a number of holes q = 1, and for a hole number q = 2, 96 slots. In addition to three-phase generators for motor vehicles and 6-phase machines with a number of holes of q = 1 are known, which then have 72 grooves in a 12-pole execution, in a 16-pole execution of the machine with a number of holes q = 1 results in 96 grooves ,

It is readily apparent from the aforementioned examples of motor vehicle generators on the market that the choice of possible number of payloads is small and that the number of slots very quickly becomes large, resulting in very narrow, difficult-to-punch teeth and small groove cross-sections for the stator , which complicate the winding of the stator and cause a bad full factor.

Furthermore, for example, from the textbook 'Electrical Machines' by Bodefeld and sequence, Springer-Verlag Wien, 1962, pages 126 ff, Bruchlochwicklungen fundamentally known. However, as the textbook example on p. 128 shows, these are only used in practice for large machines. They have a number of holes q as a quotient of the number of slots N, divided by the number of poles 2p and the phase number m, which is not an integer but a fraction. From the large machine construction are broken hole windings, especially in large

Synchronous generators known in which windings are used with a number of holes q = 2.5 or 3.5.

Disclosure of the invention

The inventive design of the stator of an alternator for motor vehicles offers over the prior art has the advantage that the aforementioned Limitations in the choice of useful numbers of the stator and the resulting mechanical and electrical disadvantages in the design and manufacture of the winding are at least significantly reduced. In particular, for high-phase machines, the structure of the stator should be improved to the effect that yield favorable punching for the stator laminations, the simplest possible winding technique and a good Nutfullung. This is achieved by the execution of the stator winding as a broken hole winding, in particular pole numbers between 10 and 20, preferably pole numbers of 12 or 16, allow a particularly advantageous structure of the machine under production engineering aspects. Small pole numbers with few claws require high forming forces for the claw poles and make their design more difficult, while too large a number of poles with small gaps between the different pole claws cause higher magnetic losses.

With regard to the number of slots of the stator winding, it is expedient if it is chosen to be greater than 1.5 times the number of poles, preferably greater than twice the number of poles. This results in a suitable limitation of the number of holes q of the winding at 10 to 20-pole machines pay numbers between 15 and 150, preferably between 40 and 100. The upper limit is determined by the manufacturing difficulties in punching filigree groove and Polgeometrien and by the problems Inserting the coils in very narrow grooves. The lower limit for suitable payloads results from a greater harmonic content in the resulting field curve of the generator and thus stronger deviations of the voltage curve from the sinusoidal shape and / or higher losses. Expedient phase numbers in the inventive execution of an alternator for motor vehicles are between 3 and 9. Too low a phase numbers require an amplified ripple in the generated voltage and thus increased magnetic noise, so a phase number of 3 should not be lower than the lower limit. High numbers of phases are generally suitable for the design of the machine, but they require an increased interconnection and component cost for the rectification of the resulting voltage in the intended use of the generator as an alternator in motor vehicles. An upper limit of 9 phases should therefore not be exceeded. In this case, a five-phase winding can preferably be designed so that an angular offset of 32 ° el to 40 ° el, in particular an angular offset of 36 ° el results between two adjacent phases. A six-phase winding can be conveniently constructed so that the six phases are connected to two star circuits offset by 28 ° el to 32 ° el, preferably by 30 ° el, with the zero points of the stars not being connected. In a seven-phase winding, the strands with the same electrical angular offset can be connected in series with each other, wherein in the series circuit each at least one adjacent strand is skipped. The stator windings are preferably constructed of conductor segments.

Values between 1/2 and less than 3, preferably values between 3/4 and smaller than 2, have proven to be suitable hole numbers q in a three-phase design of the machine. When choosing a number of phases between 6 and 9, a hole number q smaller than 1 is generally appropriate. In a particularly advantageous five-phase design of Machine are hole numbers between 1/2 and 7/4 suitable, but are also here hole numbers less than 1 to prefer. In principle, the number of holes should be as low as possible, because otherwise, especially in high-phase machines, the resulting useful number increases significantly with the already mentioned technical manufacturing and winding technical difficulties. The lower limit of the respectively suitable number of holes also results from the resulting number of slots, too low number of slots causing the mentioned disadvantages in terms of the resulting harmonic content in the air gap field.

The inventive Bruchlochwicklung is expediently designed as a two-layer winding, because this arrangement many ways when inserting the

Winding opened. The stator laminated core is preferably first produced as a flat package, because this simplifies the one hand, the insertion of the winding and on the other hand, the full factor can be significantly increased, großordnungnungsmaßig by up to 50%. In addition, the inventive Bruchlochwicklung can be performed in a design of the stator as a flat package with less overhanging the coils at the beginning and end of the flat package, so that the final bending process of the flat package to the round stator lamination with respect to the introduction of the

Wicklungsuberhange in the then adjacent grooves against a Ganzlochwicklung is much easier.

Brief description of the drawings

Embodiments of the invention are illustrated in the drawings and in the following description and in - S -

the attached tables with possible interpretations of the invention Bruchlochwicklung explained closer.

Show it

Fig. 1 is a longitudinal section through a

Three-phase generator for motor vehicles with a claw pole rotor,

2 shows a representation of a conventional three-phase all-hole winding with a number of holes q = 1,

Fig. 3 shows an exemplary embodiment of the broken hole winding for a three-phase machine with 4 poles and 15 grooves in the execution as a two-layer winding, wherein the interconnection is shown only for the phase U, and

Fig. 4 shows a detail of the laminated core of the stator in the form of a flat pack.

Embodiments of the invention

In Fig. 1 a section through an alternator 10 for motor vehicles is shown. This has inter alia a two-part housing 13, which consists of a first bearing plate 13.1 and a second bearing plate 13.2. The bearing plate 13.1 and the bearing plate 13.2 take in a stator 16, with a kreisringformigen laminated core 17, in which inwardly open and axially extending grooves, a stator winding 18 is inserted. The annular stator 16 surrounds with its radially inwardly directed surface an electromagnetically excited rotor 20 which is formed as a claw pole rotor. The rotor 20 consists inter alia of two claw-pole plates 22 and 23, on the outer periphery of each claw-pole fingers 24 and 25 extending in the axial direction are arranged. Both claw pole boards 22 and 23 are arranged in the rotor 20 such that their axially extending claw pole fingers 24, 25 alternate at the periphery of the rotor 20 as N and S poles. This results in magnetically required Klauenpolzwischenraume between the oppositely magnetized Klauenpolfingern 24 and 25. At the outer edges of the Klauenpolfinger 24 and 25 for

Noise reduction slightly chamfered, these chamfers can be reduced in cooperation with a stator 16 with a Bruchlochwicklung over a stator with Ganzlochwicklung because the use of Bruchlochwicklungen allows the improvement of the sinusoidal shape of the field curve, whereby the noise development is already reduced anyway.

The rotor 20 is rotatably supported in the respective end shields 13.1 and 13.2, respectively, by means of a shaft 27 and one respective rolling bearing 28 located on each side of the rotor. It has two axial end faces, on each of which an air filter 30 is attached. These airs 30 consist essentially of a plate-shaped or disk-shaped portion, emanating from the air blades in a known manner. These air filters 30 serve to allow air to be exchanged between the outside and the interior of the electric machine 10 via openings 40 in the end shields 13.1 and 13.2. These are the Openings 40 provided at the axial ends of the end shields 13.1 and 13.2, 30 is sucked through the air by means of the air cooler air into the interior of the electric machine 10. This cooling air is accelerated radially outwards by the rotation of the airs 30 so that it can pass through the air-permeable winding heads 45 on the drive side and 46 on the electronics side. By this effect, the winding heads are cooled. The Kuhlluft takes after passing through the winding heads, or after the flow around this winding heads a path radially outward through not shown in openings.

In Figure 1 on the right side there is a protective cap 47, the various components before

Environmental influences protects. Thus, this protective cap 47 covers, for example, a slip ring assembly 49, which supplies a field winding 51 with exciting current. Around this slip ring assembly 49 around a heat sink 53 is arranged, which acts here as Pluskuhlkorper. As a so-called Minuskuhlkorper the bearing plate acts 13.2. Between the bearing plate 13.2 and the heat sink 53, a connection plate 56 is arranged, which connects in the bearing plate 13.2 mounted minus diodes 58 and not shown in this illustration plus diodes in the heat sink 53 in the form of a bridge circuit with each other.

2 shows the diagram of a whole-hole stator winding 18 using the example of a three-phase machine having a number of holes of q = 1. The original winding of the machine is designated by 36.

This is the segment of a multi-pole winding after which the winding continues periodically. In symmetrical windings, the original winding 36 extends over one or more pot pitches of the machine, in present case about two-part divisions. At a maximum, the original winding 36 covers the entire circumference of the machine, as shown in FIG. 3 using the example of a four-pole machine with a broken-hole winding and explained there in more detail. In a Ganzlochwicklung shown in FIG. 2, the

Winding always be continued periodically after a pole pair. The original winding extends over a pole pair. Such windings are also constructed symmetrically under the two poles and designed in the case of a plug-in winding, that the winding connections are in the region of the winding head 45 on the drive side of the machine, while in the region of the opposite winding head 46, the conductors formed integrally and bent over in a U-shape are.

Fig. 3 shows an exemplary embodiment of a broken hole winding constructed as a two-layer winding with two coil sides in each groove 34 three-phase winding, for reasons of clarity, only for the phase U, the interconnection is located. The winding is shown for one

Machine with four poles, three phases and 15 slots. It can be continued in the same way periodically for all machine types with pole numbers corresponding to an integer multiple of four, in the embodiments of this application so for machines with pole numbers of 2p = 12, 2p = 16 and 2p = 20. The example shown here Bruchlochwicklung with a hole number of q = 5/4 is thus for pole numbers of 2p = 10; 14 and 18 not executable. For exportable combinations of numbers and poles, see the tables below. This results in windings that can be executed with the strong number of hole numbers that result in a symmetrical polyphase system with the number of phases m specified in the table header. While in Ganzlochwicklungen the original winding comprises a pair of poles and the winding continues periodically under all poles, there is no symmetric structure under adjacent poles in Bruchlochwicklungen. The

Urwicklung then usually extends over several pairs of poles, only with Bruchlochwicklungen with a number of holes q, which has the number 2 in the denominator, the original winding extends over a pair of poles. This therefore applies to hole numbers of q = 1/2, 3/2, 5/2, etc. However, these windings have no symmetrical structure and no symmetrical Bestromungsmuster under the two adjacent poles.

The inventive break hole winding according to the exemplary embodiment in Fig. 3 has according to the formula

q = 15 holes, 4 poles and 3 phases a number of holes

from q = 5/4 = 1.25 to. The original winding 36 thus does not extend over a pair of poles but over two pairs of poles and includes all 15 slots. The many possibilities for the interconnection of the individual coils and for the formation of the winding heads can not be represented graphically exhaustive, but they are familiar to the skilled person and can be designed without inventive intervention according to the overall structure of the machine. In this case, in particular the coil width and the connection of the individual partial coils can be chosen differently than is shown in the exemplary embodiment according to FIG. 3.

The two-layer winding according to FIG. 3 is designed as a loop winding. Often, however, wave windings are possible, which provide manufacturing advantages, because they can be easily wound with a continuous wire. Have loop windings However, shorter connections in the winding overhang 45, the plurality of Gestaltungsmoglichkeiten the winding head can not be shown here and is left to the expert.

Fig. 4 shows an advantageous under production engineering aspects design of the laminated core 17 of the stator 16 as a so-called flat package. Here, the individual disks of the laminated core 17 are punched out of straight and flat strip material, then layered and introduced the coils in the grooves 34. Thereafter, the laminated core 17 is deformed together with the finished stator winding 18 to kreisringformigen stator, wherein the overhanging coil parts are printed at the ends of the laminated core 17 following its deformation in the associated grooves 34. This method offers in the execution of the stator winding 18 as a broken hole winding special advantages, as by the Bruchlochwicklung the execution and arrangement of the winding 18 can be designed so that reduces the number of overhangs of the winding at the ends of the flat package.

The attached tables show combinations of pay numbers and pole numbers for machines with three, five, six, seven and nine phases, whereby combinations that do not lead to a symmetrical design of the machine are underlined, while the realizable combinations are not underlined in the print , The various tables each contain the possible numbers of numbers between 15 and 150 according to the number of phases and are subdivided according to the

Pole pair numbers 2p = 10, 2p = 12, 2p = 14, 2p = 16, 2p = 18 and 2p = 20. Particularly preferred combinations of payloads and associated hole numbers of the broken hole windings are in a separate table for the pole numbers 2p = 12 and 2p = 16 indicated.

In addition to the previously discussed parameters, the natural phase number m _{N also} plays a role for the feasibility of fracture-hole windings. In this case, the number N of integers must be divisible by the natural phase number m _N , otherwise a symmetrical winding can not be executed with the respective number of slots. The natural phase number m _N results from the p ^■ 360 ° phase shift of two adjacent slots. Since only voltages with this electrical slot angle or an integral multiple of them can be produced, the

natural phase number m _N = N from the quotient of

GGT (N, 2p) respective number N and the largest common divisor of the number of slots and the number of poles 2p.

The natural phase number m _N indicates which phase numbers can be realized in a machine. This is the number of phases that is a divisor of the natural number of phases. It follows for a symmetrical system that the natural phase number m _{N must be} equal to a multiple of the realizable phase number m.

In summary, it can therefore be said that the disadvantage of severely limited design possibilities of the generators, which applies especially in the case of high-phase machines, can be significantly reduced by the use of broken-hole windings. This applies in particular when using perforated hole windings with hole numbers smaller than 1, in which a large number of additional

Possibilities of realizable useful numbers results. The number of slots and the number of phases can then be chosen that the production of the machine is significantly simplified by favorable punching, simple winding technique and high Nutfullung and the electrical properties are significantly improved. In particular due to harmonics torque fluctuations and noise and

Disadvantages in terms of the resulting voltage shape and losses can therefore be significantly reduced in generators for motor vehicles with an electromagnetically excited claw pole rotor with a polyphase stator winding.

With regard to the specific embodiment of the rotor, there are no restrictions. For example, additional measures can be taken to compensate for the leakage flux between the claw poles, for example, by the arrangement of permanent magnets in the space between the claw poles. Such a design of the machine rotor is described in detail in DE 199 51 115 Al, it can also be applied to a generator according to the invention. These additional permanent magnets have a particularly advantageous effect in stator designs with a small number of poles and correspondingly wider poles, which amplify the magnetic short circuit, so that the compensation of the stray flux by the permanent magnets is particularly favorable here.

With regard to the reduction of the noise occurring during operation of the generator, further design measures can be taken, for example in the form of an encapsulation of the rotor 20 by non-magnetic covers, in particular in the region of the claw pole interspaces. Combinations of numbers and poles.

For three-phase machines the following combinations are explicitly considered:

For five-phase machines, the following combinations are explicitly considered:

For seven-phase machines, the following combinations are explicitly considered:

For nine-phase machines, the following combinations are explicitly considered:

Claims

claims

1. Alternator for motor vehicles, comprising a rotor (20) whose poles (32) are formed as claw poles, and with a stator (16) having a polyphase winding (18), which is designed as a broken hole winding.

2. AC generator according to claim 1, characterized in that the stator winding (18) is formed from three-phase to nine-phase, preferably five-phase.

3. AC generator according to claim 1 or 2, characterized in that the stator winding (18) has a number of poles

(2p) has between 10 and 20, preferably a number of poles of 12 to 16.

4. AC generator according to one of claims 1 to 3, characterized in that the number of slots (N) of the stator winding (18) is greater than 1.5 times the number of poles (2p), preferably greater than twice the number of poles (2p) ,

5. AC generator according to one of claims 1 to 4, characterized in that the number of slots (N) of the stator winding (18) amounts to 15 to 150, preferably 40 to 100.

6. AC generator according to one of claims 1 to 5, characterized in that the stator winding (18) has a three-phase (m = 3) is formed with a number of holes (q) between 1/2 and less than 3, preferably between 3/4 and less than 2.

7. AC generator according to one of claims 1 to 5, characterized in that the stator winding (18) in five phases (m = 5) is formed with a number of holes (q) between 1/4 and 7/4, preferably with a number of holes (q) less than 1.

8. AC generator according to one of claims 1 to 5, characterized in that the stator winding (18) six-phase (m = 6) is formed with a number of holes (q) less than 1.

9. AC generator according to one of claims 1 to 5, characterized in that the stator winding (18) seven-phase (m = 7) is formed with a number of holes (q) between 1/4 and 5/4, preferably with a number of holes (q) less than 1.

10. AC generator according to one of claims 1 to 5, characterized in that the stator winding (18) nine-phase (m = 9) is formed with a number of holes (q) less than 1.

11. Alternator according to one of the preceding claims, characterized in that the stator winding

(18) is constructed as a two-layer winding.

12. Alternator according to one of the preceding

Claims, characterized in that the stator lamination stack (17) is made as a flat package.