EP0380582B1 - Choke coil - Google Patents

Abstract

The so-called delta-phi choke coil exploits the effects of various core materials and/or air gap sections in the core parts on the magnetization curves of the core materials. It comprises at least two magnetically separated core sections possessing different magnetic properties, on which at least one common coil is wound. When current flows through the coil, the core sections experience the same magnetic flux. The different magnetic properties give rise to different magnetic fields in the core sections, with which selected definable inductance behaviours can be obtained by suitable choice of dimensions. In the case of special definable inductance behaviours, the delta-phi choke coil must be equipped with additional core sections and/or additional coils incorporated in an additive and/or subtractive series circuit, in a parallel circuit and/or a combined circuit.

Description

Choke coil

The present invention relates to a choke coil according to the preamble of patent claim 1.

Choke coils are used in practically all areas of electrical engineering, both in circuits where high electrical power is processed and in sound and high-frequency circuits. They are built differently depending on the application in terms of size, choice of core material, winding structure, magnetic circuit (e.g. with or without an air gap) etc.

A precise calculation of the inductance is not possible in a simple, cost-effective manner in the case of choke coils with an iron core, since several factors are involved which cannot be determined exactly.

In general, the tolerances for the inductance values of choke coils are therefore not too narrow.

In cases where the choke coil is only designed for one operating point, a specific inductance value for a specific current, and is used in a stationary system, the rough tolerance measurement does not play a major role.

However, in cases where the choke coil is designed for a specific working range, with a specific course of the inductance values as a function of the current, the choke coil is also used in vehicles such as trams, trolley buses, rail-bound railcars and Locomotives, the rough tolerance dimensioning already plays a role, since this mainly affects the geometric dimensions and the weight of the choke coil and causes problems that have to be solved.

It is the object of the present invention to provide a choke coil which solves the problems mentioned. The choke coil according to the invention should have a determinable course of the inductance values as a function of the current, and should therefore be optimally designed with regard to the electrical values, the geometric dimensions, and the weight.

This object is achieved with a choke coil which has the features listed in the characterizing part of claim 1.

The Swiss patent CH 293 283 discloses a choke coil with a magnetic circuit which is formed from two cores and a winding comprising the two cores. One core has a rectangular BH characteristic and has no air gap. The other core has an air gap, such that the magnetization characteristic of the entire magnetic circuit is composed of two approximately straight pieces of different inclinations. Furthermore, the choke coil disclosed has a pronounced step-shaped BH characteristic curve, the induction practically increasing to the maximum value even in the presence of an extremely small field strength. Choke coils with areas where the induction changes strongly with only a small change in field strength (or current change) are particularly suitable for using circuits in a known manner Switch contacts to open and close without a switch fire.

Document CH 227 740 discloses a choke coil with a magnetic circuit comprising two toroidal cores without air gap, which are arranged concentrically isolated from one another and which also serves to prevent switching fires. In this choke coil too, a steep increase in induction with only a small change in current is desired. Better values are achieved by arranging additional coils on the outer toroid and connecting them in series with main coils comprising both toroids.

Document CH 224 775 shows a switching arrangement consisting of a transformer and a switching choke in which the magnetic core of the choke is constructed from the same materials as in the aforementioned examples in order to obtain a rectangular BH characteristic with a small coercive force. The magnetic circuit of the choke coil is coupled to the magnetic circuit of the transformer via a common winding. This choke coil also has the task of preventing switching lights due to its markedly steep rise in induction with only a small change in current.

DE-OS 2 156 493 discloses a choke arrangement for connecting thyristors. The main thing here is to limit an impermissibly high inrush current without causing vibrations with impermissibly high current and voltage peaks. It is provided that the choke arrangement is effective over a relatively short time range and then as a magnetically saturated choke, which is in the load circuit of the thyristors, for the remaining duty cycle of the thyristors is ineffective. The desired current profile for the current limitation at the time of switching on the thyristors can be set by varying the number of turns, the core cross-sections, the quality of the core material and by different air gaps. The settings are made according to the switch-on characteristics and arrangements of the thyristors used. In terms of construction, the three partial choke coils are integrated into a choke arrangement, which at the same time has transformer properties, in such a way that two core packages are combined to form a sheath core, the middle leg of which is enclosed by the main winding in the thyristor main circuit, which is designed for the full load current. An auxiliary winding, which is terminated with a resistor, is present on an outer leg of one of the core packages and is magnetically coupled to the main winding.

In the drawings, choke coils according to the invention are shown in principle in various exemplary embodiments. The individual designs serve to create certain inductance curves as a function of the current. The physical background of their mode of action is also illustrated using various magnetization curves and inductance curves. The basic structure and the functional principle of the choke coil according to the invention are explained in the following description. Furthermore, the embodiments shown are described and their modes of operation are explained. The choke coil according to the invention is called delta-phi choke in the following.

Figur 1

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus dem Teilkern 1 ohne Luftspalt, dem Teilkern 2 mit dem Luftspalt L2 und den Wicklungen A, B und C;

Figur 2

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2 und 4 mit den Luftspalten L1, L2 und L4 und den Wicklungen A, C und E;

Figur 3

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2 und 3 mit den Luftspalten L1, L2 und L3 und den Wicklungen A und B;

Figur 4

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2 und 4 mit den Luftspalten L1, L2 und L3 und den Wicklungen A, B, C und E;

Figur 5

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2, 3 und 4 den mit Luftspalten L1, L2, L3 und L4 und den Wicklungen A, B, C, D und E;

Figur 6

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2, 3 und 4 mit den Luftspalten L1, L2, L3 und L4 und den Wicklungen A, B, C, D und E;

Figur 7

den prinzipiellen Aufbau der Delta-Phi-Drossel in erweiterter Bauart, bestehend aus den Teilkernen 1, 2, 3 und 4 mit den Luftspalten L1, L2, L3 und L4 und den Wicklungen A, B, C, D und E;

Figur 8

die Magnetisierungskurven Induktion in Funktion der Feldstärke für zwei verschiedene Materialien;

Figur 9

den Einfluss der Luftstrecken auf die Magnetisierungskurven Induktion in Funktion der Durchflutung:
Kurve A:  die Magnetisierungskurve für das Kernblech,
Kurve B:  die Magnetisierungskurve für eine kleine Luftstrecke,
Kurve C:  die Resultierende aus Kurve A und Kurve B,
Kurve D:  die Magnetisierungskurve für eine grosse Luftstrecke,
Kurve E:  die Resultierende aus Kurve A und Kurve D;

Figur 10

einen, aus Teilkernen (1, 2, 3, ..., n-1, n) mit teilweise mit Luftspalten versehenen, aufgebauten Kern:
Teilkern 1:  ohne Luftspalt,
Teilkern 2:  mit einem kleinen Luftspalt,
Teilkern 3:  mit einem grösseren Luftspalt,
Teilkern n-1:  mit zwei Luftspalten,
Teilkern n:  mit vier Luftspalten;

Figur 11

mögliche Luftspaltformen, dabei bedeuten:

• a) paralleler Luftspalt,
• b) Luftspalt keilförmig nach unten,
• c) Luftspalt keilförmig nach oben,
• d) Luftspalt symmetrisch keilförmig,
• e) Luftspalt trapezförmig nach unten,
• f) Luftspalt trapezförmig nach oben,
• g) Luftspalt symmetrisch trapezförmig;

Figur 12

Magnetisierungskurven Induktion in Funktion der Durchflutung für zwei Teilkerne 1 und 2:
Kurve 1  Teilkern 1 ohne Luftspalt,
Kurve 2  Teilkern 2 mit Luftspalt L2;

Figur 13

Magnetisierungskurven Induktion in Funktion der Durchflutung für drei Teilkerne 1, 2 und 3:
Kurve 1  Teilkern 1 mit Luftspalt L1,
Kurve 2  Teilkern 2 mit Luftspalt L2,
Kurve 3/4  Teilkern 3 mit Luftspalt L3,
oder
Teilkern 4 mit Luftspalt L4;

Figur 14

Magnetisierungskurven Induktion in Funktion der Durchflutung für vier Teilkerne 1, 2, 3 und 4:
Kurve 1  Teilkern 1 mit Luftspalt L1,
Kurve 2  Teilkern 2 mit Luftspalt L2,
Kurve 3  Teilkern 3 mit Luftspalt L3,
Kurve 4  Teilkern 4 mit Luftspalt L4;

Figur 15

Drosselspulencharakteristik Induktivität in Funktion des Stromes für eine Drosselspule mit 2 Teilkernen;

Figur 16

Drosselspulencharakteristik Induktivität in Funktion des Stromes für eine Drosselspule mit 3 Teilkernen;

Figur 17

Drosselspulencharakteristik Induktivität in Funktion des Stromes für eine Drosselspule mit 4 Teilkernen.

It shows:

Figure 1

the basic structure of the delta phi inductor in an expanded design, consisting of the partial core 1 without an air gap, the partial core 2 with the air gap L2 and the windings A, B and C;

Figure 2

the basic structure of the delta phi inductor in an expanded design, consisting of the partial cores 1, 2 and 4 with the air gaps L1, L2 and L4 and the windings A, C and E;

Figure 3

the basic structure of the delta phi inductor in an expanded design, consisting of the partial cores 1, 2 and 3 with the air gaps L1, L2 and L3 and the windings A and B;

Figure 4

the basic structure of the delta phi choke in an expanded design, consisting of the partial cores 1, 2 and 4 with the air gaps L1, L2 and L3 and the windings A, B, C and E;

Figure 5

the basic structure of the delta phi choke in an expanded design, consisting of the partial cores 1, 2, 3 and 4 with the air gaps L1, L2, L3 and L4 and the windings A, B, C, D and E;

Figure 6

the basic structure of the delta phi inductor in an expanded design, consisting of the partial cores 1, 2, 3 and 4 with the air gaps L1, L2, L3 and L4 and the windings A, B, C, D and E;

Figure 7

the basic structure of the delta phi inductor in an expanded design, consisting of the partial cores 1, 2, 3 and 4 with the air gaps L1, L2, L3 and L4 and the windings A, B, C, D and E;

Figure 8

the magnetization curves induction as a function of the field strength for two different materials;

Figure 9

the influence of the air gaps on the magnetization curves induction as a function of the flow:
Curve A: the magnetization curve for the core sheet,
Curve B: the magnetization curve for a small air gap,
Curve C: the resultant of curve A and curve B,
Curve D: the magnetization curve for a large air gap,
Curve E: the resultant of curve A and curve D;

Figure 10

one, made up of partial cores (1, 2, 3, ..., n-1, n) with a core partially provided with air gaps:
Partial core 1: without air gap,
Partial core 2: with a small air gap,
Partial core 3: with a larger air gap,
Partial core n-1: with two air gaps,
Partial core n: with four air gaps;

Figure 11

possible air gap shapes, mean:

• a) parallel air gap,
• b) wedge-shaped downward air gap,
• c) air gap wedge-shaped upwards,
• d) air gap symmetrically wedge-shaped,
• e) trapezoidal air gap downwards,
• f) trapezoidal air gap upwards,
• g) symmetrical trapezoidal air gap;

Figure 12

Magnetization curves induction as a function of the flow for two partial cores 1 and 2:
Curve 1 partial core 1 without air gap,
Curve 2 partial core 2 with air gap L2;

Figure 13

Magnetization curves induction as a function of the flooding for three partial cores 1, 2 and 3:
Curve 1 partial core 1 with air gap L1,
Curve 2 partial core 2 with air gap L2,
Curve 3/4 partial core 3 with air gap L3,
or
Partial core 4 with air gap L4;

Figure 14

Magnetization curves induction as a function of the flow for four partial cores 1, 2, 3 and 4:
Curve 1 partial core 1 with air gap L1,
Curve 2 partial core 2 with air gap L2,
Curve 3 partial core 3 with air gap L3,
Curve 4 partial core 4 with air gap L4;

Figure 15

Choke coil characteristic Inductance as a function of current for a choke coil with 2 partial cores;

Figure 16

Choke coil characteristic Inductance as a function of current for a choke coil with 3 partial cores;

Figure 17

Choke coil characteristic Inductance as a function of current for a choke coil with 4 partial cores.

Before going into detail about the basic structure and the mode of operation of the delta phi inductor, it should be said that it can be operated at least as a pure AC inductor and as a DC-magnetized inductor.

The basic structure of the delta-phi inductor in its simplest embodiment comprises at least two magnetically separated partial cores 1 and 2 with different magnetic characteristics and at least one winding A, which wraps around the two partial cores 1 and 2 together.

Depending on the required characteristic, inductance as a function of the current, the delta phi inductor, this is provided with further additional partial cores 3, ..., n and / or with further additional windings A1, ..., An; B; B1, ..., Bn; C; C1, ..., Cn; D; D1, ..., Dn; E; E1, ..., En.

When using several windings, the individual windings are to be connected additively or subtractively in series to winding branches, whereby, under certain conditions, parallel connection and / or the combined connection of individual windings and / or winding branches is also possible.

Additive series connection of two windings means that the magnetic induction generated by the current-carrying windings add up.

Subtractive series connection of two windings means that the magnetic induction generated by the current-carrying windings subtracts.

dabei ist:

U

= die Drosselspulenspannung in Volt

f

= die Frequenz in Hertz

w

= die Windungszahl der Wicklung A

A1

= der effektive Kernquerschnitt des Teilkernes 1 in cm2

A2

= der effektive Kernquerschnitt des Teilkernes 2 in cm2

B1

= Induktion im Teilkern 1 in Tesla

B2

= Induktion im Teilkern 2 in Tesla

If two sub-cores 1 and 2 with different magnetic characteristics are wound around a winding A through which the current I flows and with the number of turns w, both cores experience the same flux I x w. Characterized in that the two partial cores 1 and 2 have different magnetic characteristics, induction as a function of the flooding, corresponding different induction B1 and B2 are generated in the two partial cores 1 and 2. The two partial cores 1 and 2 also have certain effective core cross sections A1 and A2, corresponding to the choke coil power. The voltage induced in winding A is therefore: $$\text{U = 4.44 xfxwx (A1 x B1 + A2 x B2) x 0.0001}$$

there is:

U

= the choke coil voltage in volts

f

= the frequency in Hertz

w

= the number of turns of winding A

A1

= the effective core cross section of the partial core 1 in cm2

A2

= the effective core cross section of the partial core 2 in cm2

B1

= Induction in partial core 1 in Tesla

B2

= Induction in partial core 2 in Tesla

dabei ist:

Z

= Impedanz der Drosselspule in Ohm

U

= die Drosselspulenspannung in Volt

I

= der Drosselspulenstrom in Ampere

R

= ohmscher Widerstand der Wicklung A in Ohm

j

= die imaginäre Einheit der komplexen Schreibweise der Impedanz

ω

= die Kreisfrequenz 2 x π x f

L

= die Induktivität der Drosselspule in Henry

f

= die Frequenz in Hertz

The impedance of the choke coil at the corresponding current is thus: $$\text{Z = U / I = R + jωL}$$

there is:

Z.

= Impedance of the choke coil in ohms

U

= the choke coil voltage in volts

I.

= the choke coil current in amperes

R

= ohmic resistance of winding A in ohms

j

= the imaginary unit of the complex notation of impedance

ω

= the angular frequency 2 x π xf

L

= the inductance of the choke coil in Henry

f

= the frequency in Hertz

The reactance of the choke coil with the corresponding current is thus: $$\text{X = ω L =}\sqrt{\text{Z² - R²}}$$

The inductance of the choke coil at the corresponding current is therefore: $$\text{L = X / ω = X / (2 x π xf)}$$

The course of the inductance as a function of the current can be determined over the entire current range. All inductance behavior of the inductor can be determined using this system.

1 shows a first embodiment of a delta-phi inductor according to the invention in principle. The delta-phi inductor has two partial cores with different overall magnetic properties, the partial core 1 having no air gap and the partial core 2 being equipped with an air gap L2. The winding A wraps around the two cores together. The winding B wraps only around the partial core 1 and the winding C wraps around only the partial core 2. Through the appropriate circuit, additive and / or subtractive series circuit, and the choice of the number of turns of the windings, the magnetic behavior of the two partial cores and thus also the inductance behavior of the Delta Phi inductor can be greatly influenced.

FIG. 2 shows, in principle, a second delta-phi choke according to the invention in an expanded version with three partial cores 1, 2 and 4 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2 and L4. The winding A wraps around all three sub-cores together. The winding C wraps around only the partial core 2 and the winding E wraps around only the partial core 4. By means of the appropriate circuit, additive and / or subtractive series circuit, the choice of the number of turns, the windings, the magnetic behavior of the partial cores and the inductance behavior of the delta phi - Choke can be greatly affected.

FIG. 3 shows in principle a third delta-phi choke according to the invention in an expanded version with three partial cores 1, 2 and 3 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2 and L3. The winding A wraps around the sub-cores 1 and 2 and the winding B wraps around the sub-cores 1 and 3. Through the appropriate circuit, additive or subtractive series connection or parallel connection, the choice of the number of turns, the windings, the magnetic behavior of the sub-cores and thus the inductance behavior of the Delta Phi inductor can be greatly influenced.

In Figure 4, a fourth delta phi choke according to the invention is shown in principle in an expanded version. The delta-phi choke has three partial cores 1, 2 and 4 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2 and L4.

The winding A wraps around the sub-cores 1 and 2, the winding B wraps around the sub-core 1, the winding C wraps around the sub-core 2 and 4 and the winding E wraps around the sub-core 4. By means of the appropriate circuit, additive or subtractive series circuit, parallel circuit or combined circuit , the choice of the number of turns, the windings, the magnetic behavior of the partial cores and thus also the inductance behavior of the delta-phi inductor can be strongly influenced.

FIG. 5 shows the basic structure of a fifth delta phi choke according to the invention with four partial cores 1, 2, 3 and 4 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2, L3 and L4, and with five windings A. , B, C, D and E. The winding A wraps around the partial cores 1, 2, 3 and 4, the winding B wraps around the partial core 1, the winding C wraps around the partial core 2, the winding D wraps around the partial core 3 and the winding E. wraps around the sub-core 4. By means of appropriate circuitry, additive and / or subtractive series circuitry, parallel circuitry or combined circuitry, the choice of the number of turns and the windings, the magnetic Behavior of the sub-cores and the inductance behavior of the delta phi inductor can be strongly influenced.

FIG. 6 shows the basic structure of a sixth delta phi choke according to the invention in an expanded version with four partial cores 1, 2, 3 and 4 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2, L3 and L4, and with five windings A, B, C, D and E. The winding A wraps around the sub-cores 1 and 2, the winding B wraps around the sub-cores 1 and 3, the winding C wraps around the sub-cores 2 and 4, the winding D wraps around the sub-core 3 and the winding E wraps around the partial core 4. The magnetic behavior of the partial cores and the inductance behavior of the delta-phi inductor can be strongly influenced by appropriate switching, additive and / or subtractive series connection, parallel connection or combined connection, the choice of the number of turns, the windings.

FIG. 7 shows the basic structure of a seventh delta-phi choke according to the invention in an expanded version with four partial cores 1, 2, 3 and 4 with different overall magnetic properties, all partial cores being equipped with different air gaps L1, L2, L3 and L4, and with five windings A, B, C, D and E. The winding A wraps around the partial cores 1, 2 and 3, the winding B wraps around the partial core 1, the winding C wraps around the. Partial cores 2 and 4, the winding D wraps around the partial core 3 and the winding E wraps around the partial core 4. By means of a corresponding circuit, additive and / or subtractive series connection, parallel connection and / or combined connection, the choice of the number of turns, the windings, the magnetic behavior of the partial cores and the inductance behavior of the delta-phi inductor can be strongly influenced.

FIG. 10 shows a core divided into partial cores with different overall magnetic properties. The different overall magnetic properties are achieved in that the partial core 1 has no air gap and the other partial cores have different air gaps. The different overall magnetic properties can also and / or additionally be achieved by using materials with different magnetic properties, induction as a function of the field strength, as shown in FIG. 8. The applicable air gap sections are shown in Figure 11. The influence of the air gap section (s) on the magnetic properties of a core or a partial core, induction as a function of the flooding, is shown in FIG. 9. The magnetic field lines scatter in the zones of the air gap. So that the partial cores do not influence each other magnetically, the individual partial cores must be spaced at least by the distance which corresponds to the largest adjacent air gap.

FIG. 12 shows the magnetization curves, induction as a function of the flow, of a delta phi choke according to the invention with two partial cores 1 and 2 with different overall magnetic properties, the partial core 1 having no air gap and the partial core 2 having an air gap.

FIG. 13 shows the magnetization curves, induction as a function of the flow, a delta-phi choke according to the invention with three partial cores 1, 2 and 3 or 4 with different overall magnetic properties, partial core 1 having a small air gap, partial core 2 having a larger air gap and Partial core 3 or partial core 4 has an even larger air gap.

FIG. 14 shows the magnetization curves, induction as a function of the flow, a delta-phi choke according to the invention with four partial cores 1, 2, 3 and 4 with different overall magnetic properties, partial core 1 having a small air gap, partial core 2 having a somewhat larger air gap, the partial core 3 has an even larger and the partial core 4 has a large air gap.

FIG. 15 shows the inductance curve, inductance as a function of the current, of a delta-phi inductor according to the invention with two partial cores.

FIG. 16 shows the inductance curve, inductance as a function of the current of a delta-phi inductor according to the invention with three partial cores.

FIG. 17 shows the inductance curve, inductance as a function of the current, of a delta-phi inductor according to the invention with four partial cores.

The step-shaped inductance behavior, as shown in FIGS. 15, 16 and 17, comes about because the partial cores are designed magnetically so that the partial core 1 first reaches the magnetic saturation point at a specific current, and the induction of the remaining partial cores 2, 3 and 4 are still in the magnetically unsaturated region at this particular current. With a further increase in the current, the partial core 2 reaches the magnetic saturation point with a further determined current and the induction of the partial cores 3 and 4 are still in the magnetically unsaturated region. This state, due to a further increase in current, is carried out until all partial cores are magnetically saturated.

According to the magnetic design of the partial cores, the choice of the number of turns and the choice of the circuits of the windings, any inductance behavior, inductance as a function of the current can be achieved.

Claims (2)

1. Choke coil, especially for use in traction vehicles, with a core which has at least two part cores (1, 2, 3, ..., n) spaced apart each with a different magnetic characteristic curve (B=f(H)), at most one of the part cores being without air gap and all other part cores having at least one air gap (L1, L2, L3, ...), by which air gap the magnetic characteristic curve of the respective part core is essentially determined, as well as at least a first coil (A), which encloses at least two of the part cores, the magnetic characteristic curves of the individual part cores being harmonized in such a way that the inductivity of the choke coil decreases with increasing current essentially stair-like up to the saturation of all the part cores, and thereby that one part core after the other reaches magnetic saturation, the number of stairs of the stairway corresponding to the number of part cores, and there being at least one further coil (B, C, D, ...), which encloses at least one of the part cores (1, 2, 3, ..., n), characterized in that the coils are electrically connected together in series and/or in parallel.
2. Choke coil according to claim 1, characterized in that the individual part cores (1, 2, 3, ..., n) are spaced apart from one another by at least the distance corresponding to the largest air gap of part cores adjacent to one another.

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