EP1095383B1 - Inductive resistor system - Google Patents

Abstract

An inductance arrangement is directed to inductors, chokes and transformers with a very high power density. Chokes comprise a magnetic circuit and an electrical circuit, the latter usually comprising a copper winding. The inductance arrangement improves cooling of the magnetic circuit, efficiency of the induction arrangement, and reduces the consumption of material for the windings for a lower weight and a reduced structural size. Individual plate packs in the induction arrangement are displaced relative to each other to increase the surface area at both sides of the iron core. Displacement of the plates of the limbs allows for effective cooling passages or ducts between the core and the surrounding winding.

Description

The invention relates to an inductance arrangement or the construction of Inductors, chokes, transformers with very high power density.

Chokes are common embodiments of inductance arrangements. A such choke consists of a magnetic and an electrical circuit, the latter regularly consists of a copper winding. The magnetic circle Depending on the application, it consists of layered dynamo sheets smaller and medium frequencies, at higher frequencies e.g. made of ferrite.

Such a choke is usually made of two of each copper winding enclosed magnetically conductive legs, which are magnetic through yokes are coupled together, wherein between a leg and a yoke each according to the application, an air gap can be provided.

The inductance of such a throttle is calculated as follows: (Equation 1) L = A Fe l FE μ 0 μ e N 2 where: A _{Fe is} the iron cross section, I _{Fe is} the length of the iron path, N is the number of turns, μ _{0 is} the relative permeability, μ _{e is} the effective permeability.

The magnetic induction is calculated according to the following formula: (Equation 2) B = N · I l Fe μ 0 μ e

Magnetic induction is the determining factor in the design of inductive components or transformers. An increase in inductance Induction B always means a higher power density.

The iron losses P _{V, Fe} within the magnetic circuit (core) are squarely dependent on the induction B in a large range at low frequency. This is shown in FIG. With even greater control of the dynamo plate, the iron losses increase very strongly, which is why this area should be avoided as a rule. In conventional constructions of chokes, however, it is not possible to dissipate high power losses, since the iron legs are insulated from the environment by the coil bodies, ie the copper winding. There is practically no possibility of heat radiation (winding over core) or heat dissipation (air gap). Thus, only a small power loss can be dissipated from the magnetic circuit.

GB-A-887 081 discloses an induction assembly consisting of a magnetic Circle, wherein the magnetic circuit has at least two legs which through layered packages are formed, with individual packets of the thigh for a Area of an electrical circuit are shifted from each other so that the Surface of the magnetic circuit is increased, and wherein the legs through at least one yoke are connected.

It is an object of the present invention, the cooling of the magnetic circuit To improve the efficiency of the induction device described above to improve and significantly reduce the material consumption for the windings, so that with constant power a lower weight and a reduced Size of the induction assembly can be achieved.

This task is inventively by a Induktionsanordung solved according to claim 1.

According to the invention it is proposed that individual laminated cores in the induction assembly are shifted against each other. This will make the surface on both Sides of the iron core drastically enlarged. This enlargement of the cooling surface is easily reachable by a factor of five to fifteen. By shifting the Leg plates create very effective cooling channels between the core and the surrounding winding.

An increase of induction B by about 10% also leaves it 10% higher Number of turns too. However, the inductance increases by about 121% because - see Formula 1 - this increases in proportion to the square of the number of turns.

It is particularly effective if the mutually shifted sheets or mutually displaced laminated cores offset by 90 ° to the longitudinal direction of a Yoke are aligned. Thus, the surface by the displacement of the Sheets can be adjusted to a desired level without the winding get closer to the neighboring magnetic circuits.

Figur 1

ein Prinzipbild einer magnetischen Drossel;

Figur 2

Darstellung der Abhängigkeit der Eisenverluste von der Induktion;

Figur 3

Draufsicht auf eine erfindungsgemäße Induktionsanordnung.

Figur 4

vergleichende Darstellung der Eisenverluste in Abhängigkeit der Induktion bei konventionellen und erfindungsgemäßen Drosseln

The invention will be explained in more detail with reference to an embodiment shown in the drawings. Herein show:

FIG. 1

a schematic diagram of a magnetic throttle;

FIG. 2

Depiction of the dependence of iron losses on induction;

FIG. 3

Top view of an induction device according to the invention.

FIG. 4

comparative representation of iron losses as a function of induction in conventional and inventive throttles

Figure 1 shows the basic structure of an induction arrangement using the example of a Throttle 1. This consists in the example shown of a magnetic circuit 8, two electrical circuits 2 and depending on the application, the magnetic Circle also an air gap 3 on. The magnetic circuit in turn consists of four Elements, namely two yokes 5 and two legs 4.

The electrical circuits 2 are regularly made of a copper winding or a other metal winding.

The thighs and yokes can be layered depending on the application Dynamo plates 7 at lower and middle frequencies exist, at higher Frequencies preferably also of ferrite or iron powder.

As can be seen in FIG. 2, in conventional inductances the iron losses P.sub.V _{, Fe} within the magnetic circuit, ie the iron losses of the dynamo sheets, are quadratically dependent on the induction B in a larger range at low frequency.

At even higher modulation (with even greater induction) of the magnetic Circle or the dynamo plates increase the iron losses very strong, which is why this area should be avoided as much as possible.

With conventional construction of chokes, the magnetic circuits do not formed only from dynamo sheets, but these dynamo plates also form one compact rectangular or square core. This core, in turn, is from close electrical circuit, so the copper winding surrounded, so that the magnetic core or surrounded by the magnetic circuit leg of the Environment are isolated and therefore unable to heat to dissipate to a sufficient extent. Even if the un-wrapped parts the legs are cooled with special measures, there is no sufficient possibility of the resulting heat in the thighs over the Dissipate heat radiation or heat dissipation. Thus, despite considerable sizes only relatively low power losses from the thighs or be removed from the magnetic circuit.

FIG. 3 shows an induction arrangement according to the invention using the example of a throttle. It can be seen that the leg 4 surrounded by the copper winding 2 consist of several sheets 7, which are shifted from each other. Furthermore, the Leg plates 7 offset by 90 ° to the longitudinal direction of a yoke 5, so that by the displacement of the legs against each other the original Distance between adjacent legs is maintained. By the shift the laminated cores 7, which may be about 2 - 10 mm thick, is the surface the leg 4 is drastically enlarged on the sides. The enlargement of the surface and thus the cooling area by a factor of five to fifteen is easily achievable. There the legs 4 are still surrounded by the copper winding 2, arise very effective cooling channels, which are capable of a classic heat sink are to dissipate the heat that arises in the thighs by losses.

Due to the very intensive cooling of the legs, the induction B can be increased without that here the leg temperatures reach critical areas. An increase in the Induction B by, for example, 10% also allows a 10% higher number of turns (see Equation 2).

As can be seen from equation 1, the number of turns increases quadratically in height Inductance L, so that an increase in induction B by 10% of an increase in the Inductance L equals 121%.

Since the intensive cooling of the sheets they can be better utilized, can at the same time the legs are formed smaller, so that their weight reduced. A reduction of the legs also means a reduction of Copper winding lengths and thus also sets a significantly lower copper consumption.

Thus, the efficiency of the inductance arrangement is significantly improved.

It could be found that by the inventive measures in constant reactor power the size compared to conventional chokes by about 30 - 50% and the weight over conventional throttles by more than 40% could be reduced.

FIG. 4 shows the comparison of the required amount of iron (weight) of the iron core of a throttle. The required iron volume Fe _Vol (weight) is plotted on the Y axis. The X-axis shows the relative magnetic induction B, where B _{st is} the induction B in conventional design (standard) and B _{N is} the induction with new cooling. The dashed part B1 of the curve applies in conventional design, the solid part B2 with a new type of cooling.

The resulting iron losses are constant for the drawn curve. With the New cooling technology can dissipate more losses per unit area. Thus, As the graph shows, the throttle are built much smaller.

It can be seen here that by the measures according to the invention with the throttles a much higher induction can be applied, in which case iron losses per kilogram of iron remain significantly lower than in conventional chokes. Consequently the range of critical iron losses in the throttle according to the invention in a achieved significantly higher induction B, wherein the throttle according to the invention via a considerably smaller size than conventional chokes.

Claims (3)

1. Induction arrangement (1) consisting of a magnetic and an electrical circuit, the magnetic circuit (8) having at least two legs (4) connected by at least one yoke (5), which are formed by coated laminations (7), and the electrical circuit (2) having at least one metal winding, preferably a copper winding, single laminations (7) or several packets of laminations of the leg (4) being displaced with respect to one another in the area of the electrical circuit in such a way that the surface area of the magnetic circuit (8) is increased, and the coated laminations (7) or packets of laminations of at least one leg (4) being aligned along planes that lie perpendicular to a plane that stretches through the at least one leg (4) and the yoke (5) and parallel to the axis of rotation of the metal winding.
2. Induction arrangement according to Claim 1, one or more cooling channels (6) being formed between the at least one leg (4) and the electrical circuit (2).
3. Transformer or inductor with an induction arrangement according to one of the preceding claims, at least two electrical circuits (2) being formed, which are coupled with one another by means of the magnetic circuit (8).

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