COMMON-MODE/DIFFERENTIAL-MODE THROTTLE FOR AN ELECTRICALLY DRIVEABLE MOTOR VEHICLE

Abstract

The invention relates to a common-mode/differential-mode throttle (1) for an electrically driveable motor vehicle, with at least a core (4) having two limbs (6, 8) oriented so as to be parallel and spaced from one another, with a common-mode induction coil (L1) and with a differential-mode induction coil (L2), wherein the two induction coils (L1, L2) are each wound around one of the two limbs (6, 8). It is provided for the distance between mutually facing winding sections of the two induction coils (L1, L2) to correspond to the distance between the winding sections at least one of the induction coils (L1, L2) on either side of the respective limb (6, 8).

Claims

1. A common-mode/differential-mode choke (1) for an electrically operable motor vehicle, the choke comprising: a core (4) having at least two limbs (6, 8) aligned parallel and at a distance from one another, a common-mode induction coil (L1), and a differential-mode induction coil (L2), wherein the two induction coils (L1, L2) are each wound around one of the two limbs (6, 8), and wherein the distance between mutually facing winding portions of the two induction coils (L1, L2) corresponds to the mutual distance between the winding portions of at least one of the induction coils (L1, L2) on both sides of the respective limb (6, 8).

2. The choke as claimed in claim 1, wherein the core (4) has a center limb (7), and wherein the center limb (7) is arranged between the two limbs (6, 8) and is aligned at a distance and parallel to these.

3. The choke as claimed in claim 1, wherein the three limbs (6, 7, 8) have the same width (bs).

4. The choke as claimed in claim 1, wherein the three limbs (6, 7, 8) are connected to one another at one end by a first main limb (10).

5. The choke as claimed in claim 1, wherein the core (4) is EI shaped.

6. The choke as claimed in claim 1, wherein the core (4) is UI-shaped, EE-shaped or UU-shaped.

7. The choke as claimed in claim 1, wherein the center limb (7) ends at a distance from the second main limb (10) so that there is an air gap (l.sub.ag) between the center limb (7) and the second main limb (10).

8. A transformer with a circuit arrangement which is arranged between a high-voltage side and a low-voltage side, wherein a common-mode/differential-mode choke (1) is arranged or connected on at least one of the sides of the transformer and comprises: a core (4) having at least two limbs (6, 8) aligned parallel and at a distance from one another, a common-mode induction coil (L1), and a differential-mode induction coil (L2), wherein the two induction coils (L1, L2) are each wound around one of the two limbs (6, 8), and wherein the distance between mutually facing winding portions of the two induction coils (L1, L2) corresponds to the mutual distance between the winding portions of at least one of the induction coils (L1, L2) on both sides of the respective limb (6, 8).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The inventive inverter is notable for the inventive common-mode/differential-mode choke. This results in the above-mentioned advantages. The invention shall be explained in more detail below with the aid of the drawings, which show:

[0014] FIG. 1 a circuit diagram of an integrated common-mode/differential-mode choke and

[0015] FIGS. 2A and 2B an exemplary embodiment of the common-mode choke.

DETAILED DESCRIPTION

[0016] FIG. 1 shows, in a simplified illustration, a circuit diagram of a common-mode/differential-mode choke 1, which is realized in a component. The choke 1 has induction coils L1, L2 and LDM, wherein the induction coils L1 and LDM are connected in parallel to the induction coil L2. A first voltage drops as a result of a capacitor CX1 associated with the high-voltage power supply, and a voltage on the low-voltage side drops as a result of two further capacitors CY, between which there is a ground connection. In this case, the choke is connected, in particular, to a circuit of a transformer (not illustrated here in more detail). The coils L1 and L2 and LDM form a common-mode choke CMC and the coils L1 and LDM form a differential-mode choke DMC.

[0017] FIGS. 2A and 2B show an exemplary embodiment of the choke 1 in a simplified illustration, wherein FIG. 2A shows the dimensioning and FIG. 2B shows magnetic stray fields of the choke 1.

[0018] These show the construction of the choke 1 in a planar technique. This can also be applied to inductors wound with wires. An EI core shape of a core 3 of the choke 1 is shown in the drawing. The core 3 therefore has an E-shaped core part 4 and an I-shaped core part 5. The E-shaped core part 4 has three limbs 6, 7 and 8, which are aligned to be parallel and at a distance from one another and which stem from a main limb 9 so that the E shape is produced. The I-shaped core part 5 lies opposite the E-shaped core part 4, so that the I-shaped core part 5 lies parallel to the main limb 4 and itself forms a second main limb 10, which lies with its end face on the outer limbs 6 and 8 so that there is contact between the limbs 8, 9 and the main limb 10 or the I-shaped core part 5.

[0019] The center limb 7 lying between the limbs 6 and 8 has a shortened design, so that an air gap l.sub.ag is produced. In this case, the air gap l.sub.ag according to the present exemplary embodiment is smaller than the length IF of the outer limbs 6, 8.

[0020] The coil L1 is wound around the limb 6 as a differential-mode induction coil and the coil L2 is wound around the limb 8 as a common-mode induction coil. The limbs 6, 7 and 8 each have the same width bs so that the distance between the mutually facing winding portions of the coils L1 and L2 at their mutually facing sides in the E core part 9 is the same size as the internal diameter of the coils at the respective limb 6, 8.

[0021] In this case, the fields or magnetic fluxes shown in FIG. 2B are produced during operation. The main flux flows through the windings, so that a main field H is produced. In addition to this, each induction winding L1, L2 has a separate stray field L1S or L2S, which does not flow through the other induction winding in each case. The main field H is generated by the main inductance Lh and the stray fields by the respective stray inductances L.sub..

[0022] A coupling k between the windings of the induction coils L1 and L2 is adjusted as a result of the specific adjustment of the air gap l.sub.ag. The inductances LDM and LCM also change as a result of the change in k. LDM and Lh achieve their maximum value with an air gap of lag=0 mm. Conversely, the inductances LDM and Lh are at their minimum value with an air gap of lag=IF. In this case, the center limb 7 is omitted completely and the previous I core part 4 becomes a U core part or a U-shaped core. The stray inductance in this case depends mainly on the mutual geometric arrangement of the windings or the induction coils L1, L2. Depending on the core geometry and material, the value of Lh changes by circa 20% from the minimum value over the entire change in length of the air gap lag. In contrast to this, the value of the inductance LDM changes by circa 8000% in relation to its minimum value. Considering these very different changes in value of the inductances, it can be assumed that the value of the common-mode choke is relatively constant whilst the value of the differential-mode choke is highly adjustable. With this arrangement, values of LDM of at least pH to >100 H are achieved. The saturation of the magnetic material must again be taken into account for the dimensioning of the inductor.

[0023] The choke 1 can also be realized with two E cores or two U cores or one UI core combination. The windings of the induction coils L1 and L2 are not wound around the center limb 7 of the core as is usual; they are each wound around the outer limbs 6, 8. This increases the stray inductance L.sub. of the common-mode choke. In this construction, L.sub.=LDM and the main inductance Lh corresponds to the common-mode inductance LCM, i.e. Lh=LCM.

[0024] A further advantage comes to light in the case of high-voltage applications, since both windings or induction coils L1, L2 are not stacked on top of one another but are placed at a spacing beside one another. The insulation requirements can therefore be fulfilled without difficulty. Since the windings are not constructed on top of one another, it is moreover possible to use all copper layers for each winding. This reduces the ohmic resistance of the windings, which minimizes the copper losses of the common-mode choke. Furthermore, a greater degree of freedom in terms of the configuration of the individual windings is achieved by the construction, since they do not have to be stacked on top of one another. Since the three limbs 6, 7 and 8 have the same width bs, highly precise adjustment of the inductances is possible.