WO2007077236A1

WO2007077236A1 - Electric machine

Info

Publication number: WO2007077236A1
Application number: PCT/EP2007/050012
Authority: WO
Inventors: Gert Wolf
Original assignee: Robert Bosch Gmbh
Priority date: 2005-12-30
Filing date: 2007-01-02
Publication date: 2007-07-12

Abstract

The invention relates to an electric machine, especially an electrically excited claw pole generator (10) for a motor vehicle, comprising a stator (16). The electric machine has a stator winding (18) having at least two winding strands (70,71,72; 73,74,75) with two subcoils (70.1,70.2; 71.1,71.2; 72.1,72.2; 73.1,73.2; 74.1,74.2; 75.1,75.2) each, the at least two subcoils (70.1,70.2; 71.1,71.2; 72.1,72.2; 73.1,73.2; 74.1,74.2; 75.1,75.2) of one winding strand (70,71,72; 73,74,75) being electrically off-set to each other and the at least two subcoils (70.1,70.2; 71.1,71.2; 72.1,72.2; 73.1,73.2; 74.1,74.2; 75.1,75.2) of one winding strand (70,71,72; 73,74,75) being arranged in respect to at least one of the subcoils (70.1,70.2; 71.1,71.2; 72.1,72.2; 73.1,73.2; 74.1,74.2; 75.1,75.2) each of the other winding strand (70,71,72; 73,74,75) in phase.

Description

description

Title Electric Machine

The invention relates to an electric machine, in particular an electrically excited claw pole generator for a motor vehicle, with a stand.

State of the art

In particular, the electric machine is a multi-phase generator, which consists of a stationary stator (stator) and a rotating rotor (rotor). The following is for example the

Winding arrangement can be considered in a Klauenpolgenerator whose rotor has approximately trapezoidal Klauenpolfinger comprising an annular excitation coil.

Such, for example, designed as a generator electric machine generates in operation by electromagnetic forces a magnetic noise that can be reduced by different measures. For example, a chamfer may be applied to the claw finger outer surfaces such that a magnetic field break at a claw finger edge spreads to a larger claw finger surface. As for different

Applications with different air gaps are required (high speed - large air gap, low maximum speed - small air gap), depending on the application, there may be a significant increase in noise. Alternatively, two systems of winding arrangements are used (double system), which are wound in separate slots with a slot pitch offset corresponding to an electrical phase offset of 30 °, see also EP 0 454 039 B1. Due to the double system with an electrical phase shift of 30 °, the electromagnetic forces of the third harmonic and their multiples cancel each other, whereby the magnetic noise of these harmonics is attenuated depending on the Klauenfingerfiblings (Klauenpolanfasung). Disclosure of the invention

In the electric machine according to the invention it is provided that this has a stator winding having at least two winding strands each having at least two winding sub-strands, wherein the at least two winding sub-strands of a winding strand are electrically offset from one another and the at least two winding sub-strands of a winding strand in each case at least one of the winding sub-strands of other winding strand are arranged electrically in phase. This electric machine has the advantage that the magnetic noise is attenuated and by the variation of the electrical phase shift angle optimum tuning of chamfering of poles of a rotor of the electric machine (in particular claw poles in a claw pole generator formed electric machine) and a stator geometry of the stator can take place so that the magnetic noise, which is caused by electromagnetic forces, is eliminated in wide speed ranges. It is also possible to use claw poles with claw pole chamfers, which are optimized for 3-phase generators, since the adjustment can be made according to the phase angle. The variation of the electrical phase shift angle is obtained by varying the distribution of each winding strand in winding sub-strands, that is, by changing the proportions of the winding sub-strands on the respective entire winding strand. It is provided in particular that the winding strands are arranged in at least two winding strand groups. Each winding strand of a winding strand group is assigned a winding strand of the other winding strand group (s). Preferably, each winding sub-string of one of the winding phases of a winding strand group is assigned a winding sub-strand of an associated winding strand of the other winding strand group (s), wherein these winding sub-strands assigned to one another are arranged in phase. By varying the distribution of the winding strands in differently long winding sub-strands, the variation of the electrical phase shift angle between the associated winding strands of the winding strand groups results. Furthermore, it is advantageously provided that a voltage vector of one winding strand is electrically offset to a voltage vector of the other winding strand. In the case of a machine designed as a generator, the voltage vector is, in particular, the voltage vector of the voltage induced in the winding strand.

According to a development of the invention, it is provided that an electrical offset between the one voltage vector of one winding strand and the voltage vector of the other winding strand is characterized by an angle α, wherein the angle α is less than 30 °, preferably between 10 ° and 28 °. The two winding strands are associated with one another winding strands of different winding strand groups. The size of the angle α results from the angle between the winding sub-strands of the winding strands, the proportions of the individual winding sub-strands on the respective winding strand and the number of poles.

According to a development of the invention it is provided that the at least two winding strands belong to two different power systems. The two winding phases belong to different winding groups. Each of these winding groups is connected in an associated power system.

In particular, it is provided that a total of six winding strands are present, each three winding strands each form a three-phase system. This prevents circulating currents which would reduce the electrical power.

Furthermore, it is advantageously provided that the two three-phase systems are connected either in star-star or hexagon-hexagon (star-star-shape or hexagon-hexagon-shape). Star-star or hexagon-hex shape allows for efficient mass production and regular wire exit positions on a winding head of the stator. At these wire departure positions, the stator winding is interconnected. According to a development of the invention, it is provided that two winding strands are offset by the angle α, and the winding sub-strands are arranged in at least two immediately adjacent grooves, wherein the two grooves are associated with a pole. This arrangement results in a simple manufacturing process in forming the stator winding as a distributed winding.

Furthermore, it is advantageous if the winding strands are introduced in layers successively in the grooves. For example, if the grooves have a width that is only slightly greater than the width of a wire forming the windings, such an orderly introduction of the windings can result in a phase offset with small tolerances since each individual turn assumes a fixed position within the groove.

Finally, it is advantageous that the winding arrangement is wound from a wire, wherein the wire has a width which almost corresponds to the width of the grooves. When using such narrow grooves, each winding in a groove can be assigned a unique phase position, wherein each of the turns in a groove has the exact same phase position.

Brief description of the drawings

The invention will be explained in more detail in an embodiment with reference to the accompanying drawings. Show it:

Figure 1 shows a longitudinal section through an alternator for

Motor vehicles, with a claw pole rotor,

FIG. 2 shows a circuit diagram of an alternating current generator according to the invention in a double star connection with a downstream rectifier voltage regulator and vehicle electrical system,

Figure 3 is a circuit diagram of an inventive

Alternator in Doppelsechseckschaltung with downstream rectifier, voltage regulator and electrical system, Figure 4 representation of a winding scheme of two adjacent

Winding strands of a six-stranded designed as a simple wave winding stator winding, each winding strand of at least one continuous

Winding wire consists

Figure 5 representation of a winding scheme of two adjacent

Winding strands of a six-stranded as simple loop winding designed stator winding, each

Winding strand consists of at least one continuous winding wire and

6 shows a phasor diagram as a schematic representation of induced voltages of the winding arrangement according to FIG. 2.

Embodiment (s) of the invention

In Fig. 1 is 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 stand 16, with an annular laminated core 17, in the inwardly open and axially extending grooves 15, a stator winding 18 is inserted. The annular stator 16 surrounds with its radially inwardly directed

Surface an electromagnetically excited rotor 20, which is designed as a claw snubber. The rotor 20 consists inter alia of Klauenpolplatinen 22 and 23, at the outer periphery extending in each case in the axial direction Klauenpolfinger 24 and 25 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 north and south poles. This results in magnetically required Klauenpolzwischenräume between the oppositely magnetized Klauenpolfingern 24 and 25, which is slightly oblique because of the tapering to its free ends towards Klauenpolfinger 24 and 25 Machine axis run. For the following description of the invention and this course is simplified referred to as axial. 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. It has two axial end faces, on each of which a fan 30 is attached. These fans 30 essentially consist of a plate-shaped or disk-shaped section from which the air blades emanate in a known manner. These fans 30 serve to allow an air exchange between the outside and the interior of the electric machine 10 via openings 40 in the end shields 13.1 and 13.2. For this purpose, the openings 40 are provided at the axial ends of the end shields 13.1 and 13.2, via which 30 cooling air is sucked into the interior of the electric machine 10 by means of the fan. This cooling air is accelerated by the rotation of the fan 30 radially outward, so that they through the cool air-permeable winding heads 45 on the drive side and 46 on the drive side

Electronics page can pass. This effect cools the windings. The cooling air takes after passing through the winding heads, or after the flow around these winding heads a way radially outward through openings not shown. 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 as a positive heat sink here. As a so-called minus heat sink, the bearing plate acts 13.2. Between the end plate 13.2 and the heat sink 53, a connection plate 56 is arranged, which in the bearing plate 13.2 attached minus diodes 58 and not shown in this illustration plus diodes of a rectifier 19 in the heat sink 53 in the form of a bridge circuit interconnects.

In Fig. 2, a six-stranded generator 10 is shown schematically by a circuit diagram. The six winding strands form a first winding strand group 76 with the three winding strands (U 1) 70, (V1) 71, (W1) 72 and a second winding strand group 77 with the three winding strands (U2) 73, (V2) 74, (W2) 75 The six winding strands of the Winding string groups 76, 77 are connected to two independent three-phase systems each in the star, wherein the first three-phase system is formed by the winding strands 70, 71 and 72, each of which forms an angle of 120 ° against each other. The winding strands 70-72 are each formed by two winding sub-strands 70.1-72.1, 70.2-72.2, wherein in each case one winding sub-line 70.1-72.1 has a phase shift of 30 ° relative to the other angle sub-line 70.2-72.2 of a winding strand.

The winding strands 73, 74 and 75 are also electrically offset from one another by an angle of 120 °, wherein the winding strand 70 with respect to winding strand 73, winding strand 71 opposite winding strand 74 and winding strand 72 with respect to winding strand 75 by an electrical angle α are offset from each other. The angle α is between 10 ° and 28 °. The winding strands 73-75 are each formed by two winding sub-strands 73.1-75.1, 73.2-75.2 connected in series, one winding sub-strand 73.1-75.1 each having a phase shift of 30 ° relative to the other sub-winding 73.2-75.2 of a winding strand. Each of the two three-phase systems is connected to a separate B6 bridge rectifier 19.1, 19.2, which are interconnected on the DC side. On the DC voltage side, a voltage regulator 21 is connected in parallel, which regulates the voltage of the generator by influencing the current through the exciter winding 51. The electrical system is shown schematically by the vehicle battery 60 and by vehicle consumers 61.

In Fig. 3, a six-stranded generator 10 is schematically illustrated by a circuit diagram. The six winding strands form a first winding strand group 76 with the three winding strands (U 1) 70, (V1) 71, (W1) 72 and a second winding strand group 77 with the three

Winding strands (U2) 73, (V2) 74, (W2) 75. The winding strands 70, 71, 72, 73, 74, 75 of the winding strand groups 76, 77 are connected to two independent three-phase systems in a hexagonal arrangement, wherein the first three-phase system through the Winding strands 70, 71, 72 is formed, the resultant of each enclose an angle of 60 °. The Winding strings 70-72 are each formed by two winding sub-strings 70.1-72.1, 70.2-72.2, wherein in each case an angle sub-string 70.1-72.1 relative to the other sub-string 70.2-72.2 of a winding phase, a phase shift of 30 ° electrically. The resultant of the winding strands 73, 74 and 75 of the second

Winding strand group 77 are also electrically offset from one another by an angle of 60 °, with winding strand 70 being offset by an electrical angle α with respect to winding strand 73, winding strand 71 with respect to winding strand 74 and winding strand 72 with respect to winding strand 75. The angle α is between 10 ° and 28 °. The winding strands 73-75 are each formed by two winding sub-strands 73.1-75.1, 73.2-75.2, wherein in each case one angle sub-line 73.1-75.1 has a phase shift of 30 ° relative to the other angle line 73.2-75.2 of a winding strand. Each of the two three-phase systems is connected to a separate Bθ bridge rectifier 19.1, 19.2, which are interconnected on the DC side. On the DC voltage side, a voltage regulator 21 is connected in parallel, which regulates the voltage of the generator by influencing the current through the exciter winding 51. The electrical system is shown schematically by the vehicle battery 60 and by vehicle consumers 61.

Figures 4 and 5 show various winding patterns of a stator winding 18 with twenty-four (24) grooves 15 is shown, which corresponds to an embodiment of the rotor 20 with four Klauenpolfingern 24, 25. In practice, for the generator of a motor vehicle usually a higher number of slots and a higher number of claw-pole fingers are selected in the rotor 20, preferably a number of sixty (60), seventy-two (72), eighty-four (84) or ninety-six (96) slots 15, which corresponds to a number of ten (10), twelve (12), fourteen (14) or sixteen (16) claw-pole fingers 24, 25 at six slots per pole (rotor pole). The winding strands 70, 71, 72, 73, 74, 75 are made of continuous wire, that is, without interruption without the use of wire segments. The six-stranded stator winding 18 according to the invention is connected in the form of two separate three-phase systems, preferably in a star-star or hexagonal hexagon, as shown in FIG. 2 or in FIG. 3 and already explained in more detail there. In the Winding schemes of Figure 4 and 5 are shown by way of example only the winding strands 70, 73. Winding string 70 lies with its winding sub-string 70.1 (U11) n1 times in the grooves 1, 7, 13 and 19, where n1 = 3 and then passes into winding sub-string 70.2 (U12), which is m1 times in the grooves 2, 8, 5 is 14 and 20 and m1 = 1. Winding line 73 is located with his

Wicklungsunterstrang 73.1 (U21) n2 times in the grooves 2,8,14 and 20, where n2 = 3 here, and then turns into Wicklungsunterstrang 73.2 (U22), which is m2 times in the grooves 1, 7,13 and 19 and m2 = 1. It is also advantageous if the number of wires m1 and m2 is the same and correspondingly also io n1 and n2. This ensures that the grooves 15 are filled identically with wires. It is advantageous if n1, n2 is greater than m1, m2. It is particularly advantageous if m1, m2 is one, since here a minimal manufacturing effort arises and a very good adaptation of the chamfer on the claw finger outer surface is formed, whereby the magnetic noise under

15 Maintaining the usual chamfering for 3-phase generators - only one bevel on the trailing edge of a claw finger - is significantly reduced. Winding string 71 has the same structure as winding string 70, but the slot positions are shifted by +2 slots with respect to winding string 70, i. when winding strand 70 is inserted in the grooves 1, 2, 7, 8, 13, 14, 19, 20,

20 is winding strand 71 in the grooves 3, 4, 9, 10, 15, 16, 21, 22nd

The same applies to the winding strand 74, which is constructed identically to winding strand 73, but is displaced by +2 slots with respect to winding strand 73. Correspondingly, the structure and the slot positions for winding strand 72 result from displacement by +4 slots from the winding strand

25 and 70 of the winding strand 75 correspondingly by shifting by +4 slots out of the winding strand 73.

In the case where m1 is m2 equal to 2 and n1 is equal to n2 equal to 2, an electrical phase shift α of 0 ° occurs between the two 30-phase systems. If m1 equal to m2 equal to 3 and n1 equal to n2 equal to 1, there is an electrical phase shift α of about 15 ° between the two electrically separate three-phase systems.

In Figures 4 and 5 simple windings are shown. In a simple 35 winding extending the winding sections in the groove subsequent winding head connections in a circumferential direction of the stator 16, or substantially in a circumferential direction. But there is no restriction to use the invention for distributed windings. In a distributed winding, the winding head connections following the winding sections in the groove run essentially equally distributed in both circumferential directions and form the winding heads. The distributed winding is advantageous because the symmetry of the winding head compounds in both circumferential directions a more homogeneous Wi disgusting structure is formed and thus the flow noise is reduced.

FIG. 4 shows a winding diagram for a simple wave winding.

FIG. 5 shows a winding diagram for a simple loop winding.

FIG. 6 shows a vector representation of the induced voltages for a star arrangement according to FIG. 2. The first three-phase current system, which is formed in FIG. 2 by the winding strands 70, 71, 72, is represented by the voltage vectors 80, 81, 82 of the winding strands 70, 71, 72 is shown. Accordingly, the voltage vectors of the winding sub-strings 80.1, 80.2, 81.1, 81.2, 82.1, 82.2 are shown. The second three-phase system, which in FIG

Winding strands 73, 74, 75 is formed, is represented by the voltage vectors of the winding strands 83, 84, 85. Accordingly, the voltage vectors of the winding sub-strands 83.1, 83.2, 84.1, 84.2, 85.1, 85.2 are shown. It applies analogously to the description for FIG. 2 that the voltage vectors 80.1 to 80.2, 81.1 to 81.2, 82.1 to 82.2, 83.1 to 83.2, 84.1 to 84.2 and 85.1 to 85.2 have a phase shift of 30 ° electrically. The phase shift of the two three-phase systems α results from the angle between the voltage vectors 80, 83, or the voltage vectors 81 and 84, and the voltage vectors 82, 85. The voltage vectors of the voltages 80, 81, 82 have an electrical phase shift of 120 ° up to today. The voltage vectors of the voltages 83, 84, 85 have an electrical phase shift of 120 ° to each other.

The magnitude of the induced stresses depends on the wire number m and n of the strands in the slots. The number of poles of the electric machine 10 may in particular be between ten and eighteen. The winding arrangement can in particular be a single-hole winding arrangement, ie the number of slots corresponds to the product of the number of phases (number of phases) and number of poles, or the product of the number of winding phases and number of poles.

Claims

claims

An electric machine, in particular an electrically excited claw-pole generator (10) for a motor vehicle, comprising a stator (16) with a stator winding (18) having at least two winding strands (70, 71, 72, 73, 74, 75), each with at least two winding sub-strands (70.1, 70.2, 71.1, 71.2, 72.1, 72.2, 73.1, 73.2, 74.1, 74.2, 75.1, 75.2), the at least two winding sub-strands (70.1, 70.2, 71.1, 71.2, 72.1, 72.2, 73.1, 73.2 74.1, 74.2, 75.1, 75.2) of a winding strand (70, 71, 72, 73, 74, 75) are offset electrically relative to one another and the at least two winding sub-strands (70.1, 70.2; 71.1, 71.2; 72.1, 72.2; 73.1, 73.2; 74.1, 74.2, 75.1, 75.2) of a winding strand (70, 71, 72, 73, 74, 75) in each case to at least one of the winding sub-strands (70.1, 70.2, 71.1, 71.2, 72.1, 72.2, 73.1, 73.2, 74.1, 74.2; 75.1, 75.2) of the other winding strand (70, 71, 72, 73, 74, 75) are arranged electrically in phase.

2. Electrical machine according to claim 1, characterized in that a voltage vector of a winding strand (70,71, 72; 73,74,75) to a voltage vector of another winding strand (70,71, 72; 73,74,75) electrically offset is.

3. Electrical machine according to one of the preceding claims, characterized in that an electrical offset between the one voltage vector of the one winding strand (70,71, 72; 73,74,75) and the voltage vector of the other winding strand (70,71, 72; 73,74,75) is characterized by an angle α, wherein the angle α is less than 30 °, preferably between 10 ° and 28 °.

4. Electrical machine according to one of the preceding claims, characterized in that the at least two winding strands

(70, 71, 72, 73, 74, 75) belong to two different power systems.

5. Electrical machine according to one of the preceding claims, characterized in that a total of six winding strands (70,71, 72,73,74,75) are present, each three winding strands (70,71, 72, 73,74,75) each form a three-phase system.

6. Electrical machine according to one of the preceding claims, characterized in that the two three-phase systems are connected in either star-star or hexagon hexagon.

7. Electrical machine according to one of the preceding claims, characterized in that the two electrically separate three-phase systems are each connected to a bridge rectifier (19.1, 19.2), wherein the bridge rectifier (19.1, 19.2) are connected in parallel.

8. Electrical machine according to one of the preceding claims, characterized in that two winding strands (70,71, 72; 73,74,75) are offset by the angle α, and whose winding sub-strands (70.1, 70.2; 71.1, 71.2; 72.1, 72.2, 73.1, 73.2, 74.1, 74.2, 75.1, 75.2) are arranged in at least two immediately adjacent grooves (15), the two grooves (15) being associated with a pole.

9. Electrical machine according to one of the preceding claims, characterized in that each groove (15) has a directly adjacent groove (15) in which the same winding strands (70,73; 71, 74; 72,75) lie.

10. Electrical machine according to one of the preceding claims, characterized in that the number of slots the product of the number

Winding strands (70,71, 72; 73,74,75) and a number of poles of a rotor (20) of the electrical machine (10) corresponds.

11. Electrical machine according to one of the preceding claims, characterized in that the winding (18) is distributed or not distributed.

12. Electrical machine according to one of the preceding claims, characterized in that the winding assembly is wound or inserted from a winding wire, wherein the winding wire has a width which corresponds approximately to the width of the grooves (15).