EP2720513A1 - Inductive heating device for points and/or rails - Google Patents

Abstract

The device (1) has a generator (2) supplying alternating current (AC) sources over a line connection (22). An inductor (6) is supplied with AC and comprises an induction coil. The inductor is fastened at a rail (8) or a switch (10). Current is induced by electromagnetic induction due to the induction coil of the inductor in the rail or the switch is supplied with the AC. The current heats the rail or the switch. A control- or regulation device controls or regulates electric power of the generator by varying frequency and/or pulse width of the AC fed into the inductor. The control- or regulation device is a P-controller, a PI controller or a PID controller An independent claim is also included for a railway system for a rail vehicle.

Description

The invention relates to an inductive point and / or rail heating device comprising a generator powered by an AC voltage source which supplies via a line connection at least one at least one induction coil, provided for attachment to the rail or to the switch inductor with alternating current, due to the with AC induction coil of the inductor in the rail or in the switch by electromagnetic induction, a current is induced, which heats the rail or the switch, according to the preamble of claim 1.

Furthermore, the invention according to claim 20 also relates to a rail network for rail vehicles, including at least one rail and / or a switch, which includes an inductive point and / or rail heating device.

1. a) einem von einer Wechselspannungsquelle gespeisten Generator,
2. b) einer Leitungsverbindung zwischen dem Generator und wenigstens einem wenigstens eine Induktionsspule enthaltenden Induktor zur Versorgung der wenigstens einen Induktionsspule mit von dem Generator erzeugten Wechselstrom, und mit
3. c) einer Steuerungs- oder Regelungseinrichtung zur Steuerung oder Regelung der elektrischen Leistung des Generators durch Variieren der Frequenz und/oder der Pulsweite des in den wenigstens einen Induktor eingespeisten Wechselstroms.

gemäß Anspruch 23.Last but not least, the invention also relates to the use of an induction device with

1. a) a generator powered by an AC voltage source,
2. b) a line connection between the generator and at least one inductor containing at least one induction coil for supplying the at least one induction coil with the alternating current generated by the generator, and with
3. c) a control or regulating device for controlling or regulating the electric power of the generator by varying the frequency and / or the pulse width of the fed into the at least one inductor alternating current.

according to claim 23.

Switch and / or rail heating device serve to keep at least a portion of a rail or a rail track consisting of two parallel rails and / or a switch free of ice and snow, in order to avoid ice formation on surfaces of rails or points generally or freezing to prevent moving elements of a switch. Most widely used today are switch and / or rail heating devices, for example according to US Pat. No. 6,727,470 B2 , which work on the basis of resistance elements (heating cartridges), which are based on the principle of ohmic power generation by electrical resistance. Due to this principle of operation, however, a relatively high electrical power is necessary. The surface temperatures of rails or points heated by such switch or rail heating devices reach relatively high levels. However, only a small portion of the heat generated by the heating cartridges is transferred to the rail or to the switch. The larger remainder, however, is released into the environment via radiation in the infrared range. However, a large proportion of the energy used is lost.

Inductive point and / or rail heating devices, however, use effects of electromagnetic induction, which are induced by Wechselbestromung one or more coils of an inductor in the rail or switch electrical currents through which heat the rail or switch in question and thus free of ice and snow or keep free.

Since, as mentioned above, the surface temperature of the resistive elements (heating cartridges) is relatively high and the contact surface is limited to the rail or turnout, most of the heat is lost by radiation. In contrast, an inductor gives its relatively low heat loss almost in full to the rail or switch, which contributes to the saving of electrical energy. For the effect, therefore, no direct or close contact of the inductor with the rail or switch is necessary.

A generic inductive point and / or rail heating, for example, from DE 43 38 750 A1 known. There, a generator is used, which generates only one in its frequency invariable, especially high-frequency alternating current for the inductor, which is formed by holes in the side walls of rails extending simple wire turn.

Object of the invention

The invention has the object of providing an inductive Weichen- and / or rail heating device of the type mentioned in such a way that it is easily adaptable to the dimensions of the rail / switch to be heated and also ensures high efficiency.

Furthermore, a rail network for rail vehicles, including at least one rail and / or a switch to be further developed so that in a simple and cost-effective manner ice or snow on rails and / or switches is prevented

This object is achieved by the features of claim 1 and claim 20.

Disclosure of the invention

The invention is based on the principle of electromagnetic induction, wherein in the environment of a conductor through which an alternating current flows, in particular conduction wire windings of an inductor, an electromagnetic field arises, which in other electrical conductors, in this case a rail or switch or switch components, which are located inside this Electromagnetic field or are detected by the magnetic field lines of this electromagnetic field, causing electrical currents. These induced in the rail or in the turnout components currents cause heating of the rail or the switch components. It is the well-known transformer principle.

The closer the coupling between the inductor and the rail, the less the induced potentials scatter and the induced currents have clearly defined paths. The efficiency is higher, the closer the coupling between the inductor and the rail or the points components.

In a loose coupling between the inductor and rail, there is a scattering, the trajectories of the induced currents are then no longer clearly defined and there are eddy currents. At a greater distance, the induced current density is smaller and thus the heating is lower and in addition a part of the Field lost by the scatter. The heating of the rail or the switch components is then based on the Joule losses.

According to the invention, a control device or a regulating device is provided for controlling or regulating the electric power of the generator by varying the frequency and / or the pulse width of the alternating current fed into the at least one inductor.

This control or regulation takes place at least during operation of the inductive point and / or rail heating, optionally also before commissioning of the inductive point and / or rail heating by presetting the frequency and / or the pulse width by corresponding variable setting at least one of these Sizes provided for.

Thus, the operating parameters frequency and / or pulse width of the generator controlled and fed into the at least one inductor alternating current to the respective inductor or to the respective inductors in terms of their installation position, number and size are customizable.

A control by the control device can be done, for example, by a purely manual input of frequency and / or pulse width or even map-dependent, i. A certain measured ambient temperature or measured rail / switch temperature is assigned a specific value for the frequency and / or for the pulse width.

For example, the frequency is preferably set lower by the control or regulation, the greater the length of the rail / turnout components to be heated or the length of the induction coils of the inductors used and possibly also of the connecting lines of the inductors with each other or to the generator. The larger the length of the conductor wire of the induction coil, the lower the frequency of the excitation alternating current, which is necessary to set a necessary for generating a desired temperature in the rail or in the points components magnetic field and thus having the necessary induction current in the rail or in the points components available.

The frequency therefore serves to adapt the power of the generator to the total inductance of the electrical circuit and thus to the length of the induction coils. Conversely, the shorter the length of the rail to be heated or the switch components or the length of the inductors of the inductors and optionally the connecting lines of the inductors with each other or to the generator, the higher the frequency of the exciter AC to set to a higher To generate a desired temperature in the rail or in the switch components necessary magnetic field and thus have the necessary induction current in the rail or in the points components available.

Background of these considerations is that with increasing length of the rails to be heated or switch components and thus with increasing length of the induction coil, the impedance increases.

Therefore, by controlling or regulating the power of the generator by varying the frequency and / or pulse width of the alternating current injected into the inductors, the device according to the invention makes it possible to simultaneously provide control or regulation of the electromagnetic fields generated by the inductors. In particular, in the desired electromagnetic induction using periodic or aperiodic control or control functions pulses can be generated. Furthermore, combinations of stationary magnetic fields and pulses can be displayed.

By the possibility of adjusting the electrical power of the generator in terms of frequency and / or pulse width of the excitation alternating current for the at least one inductor over the prior art, a significant energy saving is possible because due to a possible individual adaptation of the excitation alternating current to the respective Implementation of the inductor or the inductors, the impedance, ie, the resistance is reducible.

This is particularly advantageous in view of the high number of points and rails only in German-speaking countries (about 200,000), which it is necessary to heat in the cold season. Joule-based heating systems consume 600 W to 700 W per meter of wire or cable length. With an assumed 6-month heating period and an average of 12 meters of rail / rail to be heated, the energy consumption of $$\mathrm{650}\mathrm{W}\times \mathrm{12}\mathrm{m}\times \mathrm{24}\mathrm{H}\times \mathrm{180}\mathrm{days}\times \mathrm{200}=\mathrm{6}\mathrm{739}\mathrm{200}\mathrm{MWh}\mathrm{,}$$

The inductors are preferably attached to the rails or switch components so that the generated electromagnetic fields and thus also the induced currents are concentrated on the area to be heated. This concentration can be enhanced by changing polarity and / or attachment on both sides.

Advantageous developments of the invention are the subject of the dependent claims.

Particularly preferably, the generator is controlled or regulated by the control device or the regulating device such that the frequency of the alternating current fed into the at least one inductor can be varied or set within a range of 5 kHz to 15 kHz. It has been found that a particularly high efficiency is achieved in this medium-frequency range.

Most preferably, the generator is formed without a resonant circuit or without a resonant circuit. This simplifies the construction of the generator.

According to a development, the control device or the regulating device includes at least one microprocessor which varies or adjusts the frequency and / or the pulse width of the alternating current fed into the at least one inductor via drivers.

The control device or the regulating device may further include an operating device, via which operating parameters of the generator can be set by the microprocessor.

Algorithms for controlling or regulating the power of the generator by varying the pulse width and / or frequency of the alternating current fed into the at least one inductor may be implemented in the microprocessor, the control or regulation of the power of the generator being dependent on at least one reference variable.

The at least one reference variable for the control or regulation of the power of the generator preferably includes at least the ambient temperature or the rail / switch temperature, each alone or in combination with the humidity.

In addition, preferably at least one sensor for measuring the reference variable is provided and signal-connected to the microprocessor.

1. a) bei einer von dem wenigstens einen Sensor gemessenen Umgebungstemperatur und/oder Schienen/Weichentemperatur, welche in dem Bereich zwischen dem oberen Temperaturgrenzwert und dem unteren Temperaturgrenzwert liegt, durch den Mikroprozessor eine Steuerung oder eine Regelung der elektrischen Leistung des Generators abhängig von der Umgebungstemperatur und/oder abhängig von der Schienen/Weichentemperatur als Führungsgröße erfolgt, und
2. b) bei einer gemessenen Umgebungstemperatur und/oder Schienen/Weichentemperatur, welche größer gleich dem oberen Temperaturgrenzwert ist, die elektrische Leistung des Generators auf Null oder einen Minimalwert gesetzt wird, und
3. c) bei einer gemessenen Umgebungstemperatur oder Schienen/Weichentemperatur, welche kleiner gleich dem unteren Temperaturgrenzwert ist, die elektrische Leistung des Generators einen konstanten Maximalwert gesetzt wird.

According to a particularly preferable measure, the algorithms implemented in the microprocessor for controlling or regulating the power of the generator, a temperature range between a lower temperature limit and an upper temperature limit for the ambient temperature and / or for the rail / switch temperature can be predetermined

1. a) at a measured by the at least one sensor ambient temperature and / or rail / switch temperature, which is in the range between the upper temperature limit and the lower temperature limit, by the microprocessor, a control or regulation of the electrical power of the generator depending on the ambient temperature and / or depending on the rail / vane temperature as a reference variable, and
2. b) at a measured ambient temperature and / or rail / rail temperature which is greater than or equal to the upper temperature limit is, the electric power of the generator is set to zero or a minimum value, and
3. c) at a measured ambient temperature or rail / vane temperature which is less than or equal to the lower temperature limit, the electric power of the generator is set to a constant maximum value.

According to a further development of this measure, different algorithms for the control or regulation of the microprocessor can be used in the microprocessor, starting from an average temperature which represents a middle of the range between the upper temperature limit and the lower temperature limit, either in the direction of the upper temperature limit value or in the direction of the lower temperature limit value Power of the generator to be implemented.

The control device may include, for example, a P-controller, a PI controller or a PID controller.

In addition, at least one display can be provided for displaying operating parameters.

The operating parameters preferably include the pulse width and / or frequency of the alternating current fed into the at least one inductor and / or the upper temperature limit value and the lower temperature limit value and / or the average temperature.

The at least one inductor is preferably plate-shaped, with a small thickness relative to the dimension of its side surfaces. The windings of the induction coil of the at least one inductor are preferably arranged in a single plane.

The turns of the conductor wire of the induction coil or the induction coil of the at least one inductor are, for example, in or received by a plate-shaped support body, which with one of its side faces to Attachment is provided on an inner side surface or on an outer side surface of a rail.

According to one embodiment, the inductors can be connected in the electrical circuit (serial or parallel) in such a way that their magnetic fields extend in the same direction. Alternatively, inductors arranged adjacently in the electrical circuit or on a rail or switch part can be connected in such a way that their magnetic fields have opposite directions. In other words, adjacent to a rail or a turnout arranged inductors in the electrical circuit may be connected such that their magnetic polarity alternates.

The at least one inductor may be fastened to the rail by means of a fastening device, the fastening device and the inductor preferably being interposed between at least one shielding body of electrically nonconductive but magnetically conductive material such as ferrite.

The at least one inductor is preferably attachable to the rail by means of an L-shaped bracket, wherein the L-shaped bracket has a first leg at least partially encompassing a rail and a second leg holding the inductor on a side surface of the rail, wherein the second leg Clamp and the inductor at least one shielding body of electrically non-conductive, but magnetically conductive material such as ferrite is interposed.

Preferably, the generator is controlled in accordance with a start module such that after switching on the generator, the pulse width increases at a constant frequency starting from a start value for the pulse width over a certain period ramped to a relative to a continuous power value of the generator pulse width higher value, then for a another period of time is kept constant at this increased value and, after the expiry of the further period of time, is reduced to the pulse width corresponding to the continuous power value of the generator. This brings two advantages: Firstly, a quick initial warm-up On the other hand, lowering the initially increased power to the lower continuous power allows energy savings.

The invention also encompasses a rail network with at least one rail and / or a switch which includes an inductive point and / or rail heating device as described above. In this case, at least one inductor is preferably arranged on one or both side faces of at least one rail, wherein the at least one inductor is preferably arranged in a rail section located in the region of a switch.

1. a) einem von einer Wechselspannungsquelle gespeisten Generator,
2. b) einer Leitungsverbindung zwischen dem Generator und wenigstens einem wenigstens eine Induktionsspule enthaltenden Induktor zur Versorgung der wenigstens einen Induktionsspule mit von dem Generator erzeugten Wechselstrom, und mit
3. c) einer Steuerungs- oder Regelungseinrichtung zur Steuerung oder Regelung der elektrischen Leistung des Generators durch Variieren der Frequenz und/oder der Pulsweite des in die Induktionsspule eingespeisten Wechselstroms
4. d) für eine Induktive Weichen- und/oder Schienenheizvorrichtung, bei welcher der wenigstens eine Induktor an einer Schiene und/oder an einer Weiche eines Schienennetzes angeordnet ist und bei welcher aufgrund der mit dem Wechselstrom gespeisten Induktionsspule in der Schiene und/oder in der Weiche durch elektromagnetische Induktion ein Strom induziert wird, welcher die Schiene und/oder die Weiche erwärmt.

Last but not least, the invention also includes a use of an induction device with at least

1. a) a generator powered by an AC voltage source,
2. b) a line connection between the generator and at least one inductor containing at least one induction coil for supplying the at least one induction coil with the alternating current generated by the generator, and with
3. c) a control or regulating device for controlling or regulating the electric power of the generator by varying the frequency and / or the pulse width of the alternating current fed into the induction coil
4. d) for an inductive point and / or rail heating device, wherein the at least one inductor on a rail and / or on a switch of a rail network is arranged and in which due to the supplied with the AC induction coil in the rail and / or in the switch a current is induced by electromagnetic induction, which heats the rail and / or the switch.

Fig.1

eine schematische Draufsicht auf eine induktive Weichen- und/oder Schienenheizvorrichtung gemäß einer bevorzugten Ausführungsform der Erfindung;

Fig.2

eine schematische Querschnittsansicht einer Schiene mit seitlich angebrachten Induktoren der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung;

Fig.3

eine schematische Seitenansicht von Windurigen eines Induktors der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung;

Fig.4

eine schematische Querschnittsansicht eines an einer Seitenfläche einer Schiene mittels einer abgeschirmten Befestigungsvorrichtung angebrachten Induktors der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung;

Fig.5.1

ein Temperatur-Leistungs-Diagramm, welches sich anhand einer bevorzugten Ausführung einer Steuerung oder Regelung eines Generators der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung ergibt;

Fig.5.2

ein Temperatur-Leistungs-Diagramm, welches sich anhand einer weiteren Ausführung einer Steuerung oder Regelung eines Generators der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung ergibt;

Fig.5.3

ein Temperatur-Leistungs-Diagramm, welches sich anhand einer weiteren Ausführung einer Steuerung oder Regelung eines Generators der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung ergibt;

Fig.6

eine graphische Veranschaulichung des magnetischen Flusses, welcher mittels eines Induktors der erfindungsgemäßen induktiven Weichen- und/oder Schienenheizvorrichtung in einer Schiene erzeugt wird;

Fig.7a bis d

Beispiele von Impulsfunktionen für eine beliebige zeitabhängige physikalische Größe g, die überwiegend als Hüllkurve mehrerer Pulse entstehen, worin T die Periode der jeweiligen Impulsfunktion darstellt;

Fig.8a

eine schematische Gesamtdarstellung einer Induktionseinrichtung für eine induktive Weichen- und/oder Schienenheizvorrichtung gemäß einer bevorzugten Ausführungsform der Erfindung;

Fig.8b

eine mit einem Spannungszwischenkreis arbeitende und als H-Brücke verschaltete Endstufe des Generators;

Fig.9a bis c

Beispiele periodischer Schwingfunktionen in Form von symmetrischen oder asymmetrischen Sägezähnen als Einzelwelle mit einer Periode und einer Wiederholungsrate;

Fig.10a

rechteckförmige Spannungspulse mit einer Pulsweite von 100 %;

Fig.10b

rechteckförmige Spannungspulse mit einer Pulsweite von 50 %;

Fig.11a/b

trapezförmige Funktionsverläufe ohne Pulsunterbrechung, die bei einer Begrenzung der maximal zulässigen Pulsweite in den Fig.10a und 10b nach oben bei sowohl den Größen Strom als auch magnetischem Fluss entstehen;

Fig.12

einen symmetrischen Spannungsverlauf, der ein periodisches bzw. aperiodisches Durchlaufen eines beliebigen, frei wählbaren Frequenzbereichs bei einer Frequenzmodulation mit gleichbleibender Pulsweite in einer ersten Betriebsart des Generators darstellt;

Fig.13

einen symmetrischen Spannungsverlauf, der ein periodisches bzw. aperiodisches Durchlaufen eines beliebigen Pulsweitenbereichs bei einer Pulsweitenmodulation mit gleichbleibender Frequenz in einer zweiten Betriebsart des Generators darstellt;

Fig.14

einen asymmetrischen Spannungsverlauf, der ein periodisches bzw. aperiodisches Durchlaufen eines beliebigen, frei wählbaren Frequenzbereichs bei einer Frequenzmodulation mit gleichbleibender Pulsweite in der ersten Betriebsart darstellt; und

Fig.15

einen asymmetrischen Spannungsverlauf, der ein periodisches bzw. aperiodisches Durchlaufen eines beliebigen Pulsweitenbereichs bei einer Pulsweitenmodulation mit gleichbleibender Frequenz in der zweiten Betriebsart darstellt;

Fig.16

ein Zeit-Leistungsdiagramm des Generators nach dem Einschalten, wobei die Frequenz f konstant und die Pulsweite PW variiert wird;

Fig.17

eine schematische Ansicht von Induktoren, welche im elektrischen Kreis derart verschaltet sind, dass sie magnetische Felder gleicher Richtung erzeugen;

Fig.18

eine schematische Ansicht von Induktoren, welche im elektrischen Kreis derart verschaltet sind, dass sie magnetische Felder von entgegen gesetzter Richtung erzeugen.

The invention will be described below with reference to embodiments with reference to the drawings. Show it

Fig.1

a schematic plan view of an inductive point and / or rail heating device according to a preferred embodiment of the invention;

Fig.2

a schematic cross-sectional view of a rail with side-mounted inductors of the inductive point and / or rail heating device according to the invention;

Figure 3

a schematic side view of Windurigen an inductor of the inductive switch and / or rail heating device according to the invention;

Figure 4

a schematic cross-sectional view of an attached to a side surface of a rail by means of a shielded fastening device inductor of the inductive point and / or rail heating device according to the invention;

Fig.5.1

a temperature-power diagram, which results from a preferred embodiment of a control or regulation of a generator of the inductive point and / or rail heating device according to the invention;

Fig.5.2

a temperature-power diagram, which results from a further embodiment of a control or regulation of a generator of the inductive point and / or rail heating device according to the invention;

Fig.5.3

a temperature-power diagram, which results from a further embodiment of a control or regulation of a generator of the inductive point and / or rail heating device according to the invention;

Figure 6

4 is a graphic illustration of the magnetic flux which is produced by means of an inductor of the inductive switching device according to the invention. and / or rail heating device is produced in a rail;

Fig.7a to d

Examples of impulse functions for any time-dependent physical quantity g, which predominantly arise as the envelope of several pulses, wherein T represents the period of the respective impulse function;

Figure 8a

an overall schematic representation of an induction device for an inductive point and / or rail heating device according to a preferred embodiment of the invention;

8B

a working with a voltage intermediate circuit and interconnected as H-bridge output stage of the generator;

9a to c

Examples of periodic oscillatory functions in the form of symmetrical or asymmetrical saw teeth as a single wave with a period and a repetition rate;

Figure 10a

rectangular voltage pulses with a pulse width of 100%;

10B

rectangular voltage pulses with a pulse width of 50%;

11A / b

Trapezoidal function curves without pulse interruption, which in a limitation of the maximum permissible pulse width in the 10a and 10b arise upwards for both the quantities of current and magnetic flux;

Figure 12

a symmetrical voltage waveform representing a periodic or aperiodic traversing of any arbitrary frequency range in a frequency modulation with a constant pulse width in a first mode of operation of the generator;

Figure 13

a symmetrical voltage waveform, the periodic or aperiodic traversing of any pulse width range at represents a pulse width modulation with a constant frequency in a second mode of operation of the generator;

Figure 14

an asymmetric voltage waveform representing a periodic or aperiodic sweep of any arbitrary frequency range in a constant pulse frequency modulation in the first mode of operation; and

Figure 15

an asymmetric voltage waveform representing a periodic or aperiodic sweeping of any pulse width range in a pulse width modulation with a constant frequency in the second mode;

Figure 16

a time-power diagram of the generator after switching on, wherein the frequency f is varied and the pulse width PW is varied;

Figure 17

a schematic view of inductors, which are connected in the electric circuit such that they generate magnetic fields of the same direction;

Figure 18

a schematic view of inductors, which are connected in the electrical circuit such that they generate magnetic fields of opposite direction.

Description of the embodiments

Fig.1 FIG. 2 illustrates a schematic plan view of an inductive point and / or rail heating device 1 according to a preferred embodiment of the invention. This device includes an electrical generator 2, which is supplied with alternating current, for example, from a standard 50 Hz alternating current network. The generator 2 is part of an electrical circuit 4, which preferably includes series-connected inductors 6.

The inductors 6 are preferably each arranged on an outer side surface 12 of two parallel rails 8 in the region of a switch 10, like in particular Fig.1 . Fig.2 and Figure 4 evident. Alternatively, the inductors 6 may also be arranged both on the inner side surface 14 of the rails 8 and on the outer side surfaces 12 of the rails 8, as in FIG Fig.2 is indicated. In the present case, the mobility of the switch 10 is obtained by heating two parallel rails 8 of a rail track in the region of the switch 10 through the inductive switchpoint and / or rail heating device 1 even at low temperatures or risk of icing. Alternatively or additionally, but also parts components of the switch 10 could be heated.

For heating the rails 8 12 and / or 14 inductors 6 are preferably attached to the side surfaces thereof. The side surfaces 12, 14 are preferably side surfaces of a rail middle part 16, which seen in vertical direction or in cross section between a lower rail foot 18, which rests mostly on a sill and an upper rail head 20, on which the running and flanges of the wheels Roll off rail vehicles and also be guided laterally.

inducers

The inductors 6 are preferably plate-shaped, that is to say they have a relatively small thickness measured on the dimension or extent of their side surfaces. The inductors 6 are arranged, for example, equidistantly with respect to the length of the rail or the rails 8 on their side surfaces 12, 14. The inductors 6 are preferably connected to one another in series by electrical connection lines 22 of the electrical circuit 4.

The plate-shaped flat design of the inductors 6 in combination with their attachment to the side surfaces 12, 14 of the rails 8 ensures that the inductors 6 can not be detected by the flanges of the wheels of the rail vehicles.

How out Figure 3 As can be seen, such an inductor 8 includes an induction coil 56 with turns 24 of a conductor wire, which are arranged within a single plane, in particular in the plane of the plate. The number of here, for example spirally designed turns 24, the expert can adjust as needed. The windings 24 are preferably cast in a plate-shaped carrier body 26, for example, wherein in each case one end of the conductor wire of the turns 24 protrudes from the shaped body 26 in order to be connected to the electric circuit 4 and to close the electric circuit 4.

The plane of the turns 24 of the conductor wire of the induction coil 56 is arranged substantially parallel to the associated side surface 12 or 14 of the rail 8. How through Figure 6 illustrated, when Wechselbestromung the conductor wire of the windings 24 of an inductor 6 in a certain direction (dots in the circle symbolize a flowing out of the plane and a cross in the circle symbolizing a flowing current in the plane) a magnetic field 28, which also detects the relevant, electrically conductive rail 8 and penetrates into this preferably substantially perpendicular to the side surface 12 and / or 14 in order to induce a current there by induction.

The inductor 6 is preferably arranged such that the magnetic flux or the magnetic field lines 28 generated by its induction coil 24 are preferably perpendicular to a surface 12 or 14 of a rail 8 or a switch component of a switch 10 (FIG. Figure 6 ).

The current induced in the rail 8 causes heating of the rail 8 in the region of the switch 10. The heating of the rail or of the rails 8 in the region of the switch 10 causes no ice between the rails and the guides of the switch for the rails. or snow layer, which could block movement of the rails 8 moved by the switch 10.

Alternatively, or in addition to the rails 8 also switch components of the switch 10 could be inductively heated by inductors 6, which are arranged accordingly, so that the magnetic field lines can penetrate approximately perpendicular to surfaces of the switch components, where the inductors 6 are arranged.

The magnetic field generator is therefore preferably composed of a plurality of individual inductors 6 preferably connected in series, each having an identical or different length of conductor wire or identical or different physical properties with respect to its conductor wire (inductance, material, diameter, number of turns 24, etc.). ). In order to ensure the same energy production per length, the individual inductors 6 in the electrical circuit 4 are preferably connected in series.

Alternatively, with partial or total agreement of the physical properties of the individual inductors 6, these can also be connected partially or completely in parallel into the electrical circuit 4. It is also conceivable, however, a combination of series and parallel connection of the individual inductors. 6

In the case of a serial circuit, the individual inductors 6 can be optimally adapted to the local rail conditions by producing them in variable lengths relative to the rail longitudinal direction. You can also be seen overlapping attached left side and right side of the rail in question 8, then seen in particular in the longitudinal direction of the rail 8.

The inductors 6 can be connected in the electrical circuit 4 so that they generate the magnetic field not only in the same direction preferably perpendicular to the side surface 12, 14 of the rail 8, but for example in the opposite direction, but again preferably perpendicular to the side surface 12th , 14 of the rail 8.

In Figure 17 an embodiment is shown in which arranged on a rail 8 inductors 6 are preferably connected in such a way in the electric circuit 4 (serial or parallel) that their magnetic fields in the same direction, there each symbolized by the "+" in a circle.

Figure 18 shows, however, an embodiment in which two in the electrical circuit 4 adjacent arranged inductors 6 generate magnetic fields opposite directions, which symbolizes there by the "+" in the circle or the "-" in the circle becomes. In particular, according to the embodiment of Figure 18 the inductors 6 so interconnected in the electrical circuit 4, that along a rail 8 their magnetic polarity alternates. The opposite polarity of the inductors 6 results in higher temperatures in the rails 8, so that this measure brings a further energy savings.

The inductors 6 are preferably attached laterally to the rails 8 with an outer surface of their carrier body 26 directly or with a minimum distance. For this purpose, the carrier body 26 carrying the windings 24 of the conductor wire may be shaped such that its side surface facing the side surface 12, or 14 of the relevant rail conforms seamlessly to the side surface 12 or 14 of the rail 8.

The intrinsic heat of the inductors 6 is transmitted in this way directly to the rails 8 by contacting heat transfer, wherein the inductors 6 are also cooled by rails 8. The attachment of the inductors 6 to the rails 8 by any fastening devices, preferably by screws, gluing, permanent magnets or by mechanical clamping systems. The attachment of the inductors 6 to the rails 8 must be designed so that it is sufficiently resistant to the weather and mechanical stress such as vibrations.

A preferred fastening device for fastening a plate-shaped inductor on a side surface of a rail, for example, in an L-shaped elastic clip 30, with a first leg 32 at least partially embracing the rail and a holding the inductor 6 on the side surface 12 and 14 of the rail 8 second leg 34, as in Figure 4 is shown.

The first leg 32 engages around the rail 18 from below. The second leg 34 then exerts a lateral bias on the inductor 6, so that it is urged against the side surface 12 and 14 of the rail 8. Thus, the attachment of the inductors 6 on the side surfaces 12 and 14 of the rails 8 based on frictional engagement, the Vorpsnanung of the legs 32, 34 of the clip 30 is exercised. The second leg 34 of such a clip 30 may be formed such that the ends of the second leg 34 each bent on the end faces of the plate-shaped inductors attack 6 and thereby fix them in the vertical direction.

In a central part of the second leg 34 may also have a convex bulge 36 seen from the inductor 6 to contact the inductor 6 and a shielding body 38, so that a lateral contact force is exerted on the inductor 6 and the shielding body 38, which first leg 32 is then supported on the rail 18. The bracket 30 is then in the cross section of Figure 4 seen burdened on bending. The clip 30 is preferably made of an electrically conductive metal.

How out Figure 4 Also shows, the second leg 34 of the bracket 30 and the inductor 6 at least one preferably plate-shaped shielding body 38 of electrically non-conductive, but magnetically conductive material such as ferrite interposed. This shielding body 38 ensures that the clamp 30 is not heated when the windings 24 of the inductor 6 are traversed by alternating current. In order to prevent or at least limit heating of the clamp 30, it is therefore preferably shielded by a ferromagnetic and non-conductive shielding body 38 from the primary electromagnetic fields.

Manual setting of the generator

According to a preferred embodiment, in which the operating parameters frequency and / or pulse width of the generator 2 are manually adjustable, is an in Figure 8a shown operating means 40 provided with adjusting means 42 for manually and separately adjusting the frequency and / or the pulse width of the fed into the electric circuit 4 and in particular in the inductors 6 alternating current. Preferably, both the frequency and the pulse width of the excitation alternating current can be varied here by the adjustment means. Alternatively, only one of these operating variables or parameters could be varied.

As in Figure 8a schematically illustrates controls the control device 40 with the adjustment means 42, the set values for the frequency and / or the pulse width in a microprocessor 44, which in turn controls the generator 2, which then sets the said variables in the electrical circuit via drivers. In this case, a display 46 may be present on which the set values for frequency and pulse width can be displayed.

The manual adjustment of the frequency and / or the pulse width can of course be done before the operation of the device 1 or even during operation.

power control

According to another, also in Figure 8a In the embodiment shown, the microprocessor 44 could also regulate the pulse width and / or the frequency of the excitation alternating current controlled by the generator 2 as a function of at least one reference variable such as the ambient temperature or the rail / switch temperature or else depending on one of these temperatures in combination with the air humidity. It is conceivable as an additional reference variable also a detection of other environmental parameters such as snowfall. Humidity or snowfall are important because they have an influence on the formation of ice near switches.

For sensing the reference variable or the reference variables, a corresponding sensor 48 is provided, which in Figure 8a is symbolized by a symbolized in dotted line signal line 48 to the generator 2 to symbolize in this regulated embodiment, the sensor 48 as compared to a control or manual adjustment of the power of the generator 2 additional assembly.

The electric output power of the generator 2, which is supplied to the inductor (s) 6, is regulated, in turn, by changing the pulse width and / or the frequency of the exciter alternating current, which flows through the inductor (s) 6, depending on the command variable or the command variables. According to a preferred embodiment, the sensor system 48 comprises at least one ambient temperature sensor for measuring the ambient temperature and / or at least one temperature sensor installed on the rail / switch 8, 10 (measuring the temperature of at least one rail 8 or switch components in the region of a switch 10), temperature signals be controlled for the actual ambient temperature or for the actual rail / switch temperature in the microprocessor 44, in which the control or regulating algorithms are implemented.

The power control of the generator 2 is preferably accomplished by a continuous change of the pulse width. It is also possible to perform the power control by frequency modulation. However, then the efficiency is slightly worse.

An example of a power control process is in Fig.5.1 represented where the electrical power of the generator 2 (in kW), which is proportional to the pulse width, depending on the ambient temperature (in ° C) is shown. As can be seen, the power output of the generator 2 is hereby controlled in a linear manner between two freely adjustable ambient temperature limit values as a function of a reference variable, here for example the ambient temperature, namely between a lower temperature limit value (here -15 ° C.) and an upper temperature limit value (here, for example + 5 ° C) for the ambient temperature.

Is therefore in the example of Fig.5.1 the ambient temperature is less than or equal to the lower temperature limit Tu (here, for example, -15 ° C.) or greater than the upper temperature limit To (here, for example, + 5 ° C.), then a constant but different electrical output or pulse width is set. For example, between the two temperature limits To and Tu the power output or the change of the pulse width runs linearly dependent on the reference variable (P-controller).

According to another, in Fig.5.2 and Fig.5.3 illustrated mode can be a mean temperature Tav (here (here, for example -5 ° C), which are used exactly in the middle of the range between the upper temperature limit To (here, for example, + 5 ° C) and the lower temperature limit Tu (here, for example, -15 ° C). The abscissa is again the ambient temperature and the ordinate is the electric power of the generator 2 (in kW). In this mode, depending on the change of the ambient temperature from the average temperature Tav to either the upper temperature limit To or the lower temperature limit Tu, different control algorithms for the output of the generator 2 are set.

Via the display 46 of the operating device 40, the lower and upper temperature limits To, Tu as well as the average temperature Tav can be entered. These are empirical values, but these can be adapted to local circumstances if necessary.

All control operations can be linear (P control). But it is also possible to perform the control operations as PI or PID control or to combine with each other. Consequently, any control algorithms are possible.

In the example of Fig.5.1 is a P-control realized in which a linear range between the upper temperature limit To (here: + 5 ° C) and the lower temperature limit Tu (here: -15 ° C) is present. At ambient temperatures greater than or equal to the upper temperature limit (here + 5 ° C), however, the generator 2 operates with a constant minimum power output, the pulse width can be lowered to zero. At an ambient temperature less than or equal to the lower temperature limit (here -15 ° C), the generator 2, however, operates at maximum electrical power.

But it is also possible to set a freely selectable temperature-dependent correction factor via the operating device 40. For example, the correction factor indicates a percentage of the power output per ° C set for the average temperature Tav. The regulation then refers to the average temperature Tav and changes the power output eg between zero and maximum permissible electrical power. Again, two different advantageous Correction factors for both directions, starting from the average temperature Tav up to the upper temperature limit and down to the lower temperature limit.

line control

According to a further embodiment, the power of the generator 2 is controlled by means of the microprocessor 44 by changing the pulse width and / or the frequency of the excitation alternating current driven by the generator 2 as a function of the ambient temperature and / or of the rail / switch temperature according to at least one predetermined characteristic diagram , These temperatures are in turn reported by corresponding sensors to the microprocessor 44, in which the map is stored.

In a freely determinable ambient temperature range, in particular in a temperature range of +5 ° C to -15 ° C, the output of electrical energy, for example, over the pulse width of the exciter AC current according to a specific algorithm, for example linear as in Fig.5.1 controlled. For example, at an outside temperature of + 5 ° C and above, the output by the generator 2 electrical power is driven by controlling the pulse width to zero, at -15 ° C and less, however, the maximum electric power is set on the generator 2, as well as in Fig.5.1 shown.

Since the generator 2 preferably has no resonant or oscillatory circuit and therefore operates without resonance, the frequency of the excitation alternating current is furthermore freely adjustable with regard to the physical properties of the inductors 6. The height of the induced currents is dependent on frequency and field strength. The field strength is directly proportional to the excitation alternating current flowing through the inductor 6 or the inductors 6 given the prevailing conditions.

The optimum for the energy transfer, in particular for the value of the frequency of the excitation alternating current is therefore determined by the physical properties of the inductor 6 or the inductors 6. It was found that a particularly high efficiency in a medium frequency range of 5 kHz to 15 kHz is achieved. The electrical energy requirement of the device is then on average below 250 W / m, which is approximately a magnetic field strength H of 200 A / m. This value is dependent on the inductor, it can also be less than 100 A / m). The temperature increase dT in the rail 8 / switch 10 with a constant supply of electrical energy is about 20 K.

Operating modes of the device

According to one mode of operation, the inductive point and / or rail heating device 1 is remotely switched on or off, for example, from a railroad station, in which case an operation, for example, with previously set constant operating parameters (frequency, pulse width), with map control during operation or manually varied operating parameters (frequency, pulse width) as well as regulated is possible.

According to a further mode of operation, the inductive point and / or rail heating device 1 is operated continuously over a given heating period (eg from October to March of each year in the northern hemisphere) with constant adjusted electrical power, with variable manual or map-controlled power or with regulated power ,

Since the temperature rise rate in the rail 8 / turnout 10 depends directly on the output electrical line of the generator 2, the electrical power of the generator 2 according to another mode immediately after switching on the generator 2 or immediately after activation of the device 1 for a certain Increased time span and then driven back to an operating value. If the microprocessor controlling the generator 2 is operating in control mode, control is suspended for that period of time. However, the control can also be set so that this mode automatically adjusts after switching on the device 1 or the generator 2.

Operating modes of the generator

For the generation of the electromagnetic field by the inductors 6, these are preferably excited only by periodic oscillation functions of the excitation alternating current. By means of square voltage pulses symmetrical trapezoidal current pulses are preferably generated with freely adjustable ratio between a dynamic and a static component. For a process flow, by means of the operating device 40 which controls the microprocessor 44, one can choose between modes of a constant mode, a frequency mode, a pulse width mode and a magnetic flux mode combining the frequency mode and the pulse width mode. Furthermore, there is also a basic mode according to which the characteristics of the excitation alternating current are not changed. These operating modes or modes of the generator 2 are stored as control software in the microprocessor 44 and can be adjusted via the operating device 40.

The implemented in the microprocessor 44 control software for the generator 2 for generating alternating magnetic fields preferably includes a combination of higher frequencies, preferably frequencies in the kHz range, with a superimposed modulation in the low-frequency range such that preferably only swing or change functions (and thus no Pulse or pulse functions) with a rectangular voltage curve and trapezoidal current waveform arise.

Thus, these curves from a frequency range of, for example, 5 kHz to 60 kHz, preferably 5 kHz to 15 kHz continuously modulate through freely selectable periods of time, wherein the higher-order modulation is preferably in a range between 0.1 to 10 Hz. Technically possible would be a range between 0 Hz (no alternating field) and 50 Hz, if a continuity at frequencies higher 10 Hz can be represented. In practical terms, this results in a higher-level modulation of 0.5 Hz for a section time of one second, a higher-level modulation of 5 Hz for a section time of 100 ms, and so on. The frequency values are changed according to the clock of the microprocessor 44, for example a thousand times per second. These The procedure is applicable to all the above operating modes. The low frequency range of preferably 0.1 Hz to 10 Hz, by having the superordinate modulation, can advantageously enhance the effects of the resulting electromagnetic field changes on the rail / shunt.

According to a basic mode of operation of the generator 2, the frequency as well as the pulse width of the exciting alternating current are kept constant.

According to a first operating mode of the generator 2, the frequency of the excitation alternating current is continuously changed while the pulse width remains constant. In addition to the well-known advantages of frequency modulation, a continuous frequency change can be realized favorably in a control software.

According to a second mode of operation of the generator 2, the pulse width of the excitation alternating current is continuously changed while the frequency of the excitation alternating current remains constant. In the realization of the continuous pulse width change, for example, for example by means of MOSFETs or IGBTs, these can advantageously operate in low-loss switching operation. Further advantageously, the information to be displayed is contained in a continuous pulse width ratio instead of in a binary manner.

Furthermore, there is a third mode of the generator 2, which is a combination of the first and second modes, wherein both the frequency and the pulse width of the excitation alternating current are continuously changed. This third operating mode particularly advantageously combines the advantages of the continuous pulse width change and the continuous frequency change. Here, both the frequency and the pulse width are continuously preferably changed such that the magnetic flux remains constant.

The generator control in the microprocessor 44 is constructed so that said modes are freely programmable and storable.

The output stage 52 of the generator 2 operates with a voltage intermediate circuit and is, as in 8B shown, preferably exclusively connected as H-bridge. The power elements, such as MOSFETs or IGBTs, are in 8B shown as switch 54 with associated freewheeling diodes. This circuit allows the utilization of the energy stored in the induction coils 56 for the generation of trapezoidal pulses without additional frequency or pulse width modulation.

Advantageously, the time relationship between a dynamic and a static profile of the inductor 6 adjusting magnetic field is freely adjustable. Due to the different effects of dynamic and static magnetic fields, a desired overall effect can thereby be tuned. With electroconductive loads there are no static courses, with ferromagnetic loads they are impossible, with paramagnetic or diamagnetic loads they are transfer-dependent, the more is induced the farther is the "statics".

It is also advantageous if limit values for all operating modes are freely adjustable. This ensures that application-related limit values can be reliably met.

It is also advantageous if time constants required for the individual operating modes are all freely adjustable. This improves the controllability of the generator 2 and thus of the electromagnetic field to be generated.

The first, second and third operating modes preferably have signal waveforms with a variable period number. This also advantageously improves the controllability of the electromagnetic field to be generated. Alternatively, the first, second and third modes may include constant period waveforms. This also advantageously improves the controllability of the electromagnetic field to be generated.

As detailed above, a frequency and / or pulse width modulation is performed for the power control or power control of the generator 2.

For outdoor generators 2, it may not be advisable for thermal reasons, during a very cold period, for example, at ambient temperatures of -20 ° C and less to turn on the full generator power abruptly. It is then more advantageous to ramp up the power of the generator 2. In the context of a start mode of the generator 2, the generator power is set, controlled or regulated by varying the pulse width PW at a constant frequency f.

The diagram of Figure 16 shows the performance of the generator in the start mode after turning on the generator at a constant frequency f and variable pulse width PW. After the switch-on time at t = 0, the power or the pulse width PW of the generator 2 is increased at a constant frequency f from a start value PW ₀ for the pulse width preferably ramp-like over a certain period of time tr, for example, to a value PW ₁ , which is greater than a continuous power value PW ₂ , which is necessary to obtain the desired result of induction (eg, a desired rail temperature). This increased value PW ₁ is then preferably maintained constant over a subsequent period t1 to the period tr before the other hand, lower continuous power value PW ₂ is set from a time t2. Preferably, the period of time tr, during which the generator 2 is ramped from zero to the increased power or increased pulse width PW ₁ after switching on, and the time period t1, during which the generator 2 is operated with the increased power PW ₁ , adjustable, For example, via the operating device 40. This has two advantages: First, a rapid initial warming is achieved and, secondly, lowering the power from PW ₁ to PW ₂ makes it possible to save energy. This start mode is in particular independent of the other operating modes of the generator.

Physical background

Some examples of pulse functions for any time-dependent physical quantity g, here the excitation alternating current of the induction coils 56, which arise predominantly as the envelope of several pulses are in the FIGS. 7a to 7d where T represents the period of the respective impulse function.

Furthermore, methods are known in which periodic oscillatory functions in the form of symmetrical or asymmetrical saw teeth are used as a single wave with a period of eg 10 ms (T1, corresponding to 100 Hz) with a repetition rate of 100 ms (T2, corresponding to 10 Hz). Examples of such periodic oscillatory functions are in FIGS FIGS. 9a to 9c shown.

If, in the following, a function is referred to as "pulse" or "pulse", it is always a function course during a half-period. This is followed by a pulse with the opposite sign. In the case of a voltage curve, the positive and negative pulses take place with a zero phase between the two half-waves; in the case of a current profile and / or a field profile, this sequence is uninterrupted. In this case, the two half-waves form a periodic alternating function.

The magnetic flux Φ is directly proportional to the electric current I causing it. The proportional constant is called inductance L and represents the characteristic size of an inductor: $$\mathrm{\Phi }=\mathrm{L}\times \mathrm{I}$$

The above equation states at the same time that the course of the magnetic flux in linear systems faithfully follows the course of the current. If the current i increases linearly, the flux Φ also increases linearly; if the current i is constant, the flux Φ also assumes a constant value.

wobei die induzierte Spannung $$\mathrm{u}=-\mathrm{d\Phi }/\mathrm{dt}$$

ist. Je höher die Frequenz f ist, desto höher ist auch die induzierte Spannung u. Allerdings ist auch eine hohe Feldstärke Φ notwendig, d.h. es wird dazu ein größerer Strom i benötigt. Strom i und Feldstärke Φ zusammen bestimmen den Arbeitsbereich (Spannung und Frequenz) am Generatorausgang.Since these are linear systems and time-dependent curves, ie alternating currents, the equation can be differentiated by time: $$\mathrm{d\Phi }/\mathrm{dt}=\mathrm{L}\times \mathrm{di}/\mathrm{dt}$$

the induced voltage $$\mathrm{u}=-\mathrm{d\Phi }/\mathrm{dt}$$

is. The higher the frequency f, the higher the induced voltage u. However, a high field strength Φ is also necessary, ie it requires a larger current i. Current i and field strength Φ together determine the working range (voltage and frequency) at the generator output.

Particularly advantageous is a perpendicular to a surface of the rail, in particular to a side surface of the rail extending direction of the field lines shown (see Figure 6 ). The magnetic field strength or the induction of the magnetic field produced by the induction coil 56 is controlled by means of a frequency and / or a pulse width modulation.

As explained above, a control of the power of the generator 2 by a frequency modulation is referred to as a first mode, a control by means of a pulse width modulation as a second mode, and a control by a combination of a frequency modulation and a pulse width modulation referred to as a third mode.

It is preferred to use exclusively periodic oscillatory functions which assume both positive and negative values, without these having to be in a defined relationship to one another. A periodic function satisfies the equation: $$\mathrm{f}\left(\mathrm{t}+\mathrm{T}\right)=\mathrm{f}\left(\mathrm{t}\right)$$

In the limiting case, the oscillating functions are transformed into alternating functions, whereby the positive and negative areas bounded by the voltage curve are identical within one period.

Both positive and negative voltage pulses are rectangular. In Figure 10a is the pulse width PW at 100%, in 10B shown with 50%. The control signals for the current and thus also for the course of the current are generated in such a way that there is no interruption in both irrespective of the respective pulse width. If the maximum permissible pulse width is limited to the top - eg 75% - both types of current and flux - uninterrupted trapezoidal function curves without pulse interruption occur, as in the Figures 11 a and 11 b are shown.

According to a basic mode of operation of the generator, a constant frequency f and a constant pulse width PW are maintained. The generator 2 then works in a so-called $$\mathbf{t\_mode\; at\; f}=\mathbf{const}\mathbf{,}\mathbf{and\; PW}=\mathbf{const}\mathbf{,}$$

The first operating mode or frequency mode allows a corresponding periodic or aperiodic passage through any arbitrary frequency range via corresponding control specifications, wherein the frequency f is increased or decreased over corresponding freely selectable time constants. The pulse width PW remains constant. This corresponds to one in Figure 12 shown frequency modulation: $$\mathbf{f\_mode\; at\; PW}=\mathbf{const}\mathbf{,}$$

Especially this mode is advantageous because from a higher frequency f a lower current i results and thus the power consumption decreases and at the same time the transmission improves, i. the induced voltage u and thus the induced currents i become larger.

In Figure 12 the pulse width PW = 50% was selected. The individual pulse widths PW are representative of a packet of equal pulses. If the first positive pulse corresponds, for example, to a frequency f of 10 kHz and the frequency f is incrementally increased in accordance with the cycle time of a microprocessor control of 1 ms, 10 pulses with the same pulse width result next to each other - both in positive and negative also in the negative direction. The step size for increasing or decreasing the frequency f results automatically from the preselected limit values and from the time for a frequency cycle.

The second operating mode or pulse width mode enables a periodic or aperiodic passage through an arbitrary pulse width range at constant frequency via corresponding control specifications. This corresponds to one in Figure 13 shown pulse width modulation: $$\mathbf{PW\_mode\; at\; f}=\mathbf{const}\mathbf{,}$$

The procedure for this second operating mode is analogous to the first operating mode f_mode.

Both operating modes, the first operating mode (frequency mode) and the second operating mode (pulse width mode) simultaneously result in a change in current and thus also in a flux change. Both quantities can be continuous, i. be changed in a ramp, or jump between two freely selectable limits.

It is preferably provided that all changes can be made symmetrically or asymmetrically. Alternatively, the sequence of the first and the second mode of operation can only take place in one direction, for example in a frequency cycle of, for example, 10 kHz to 30 kHz. After reaching the 30 kHz limit, a jump automatically takes place back to 10 kHz, after which the frequency rises again to 30 kHz. The frequency cycle can be done with variable pulse rate and the same time for all frequencies, ie with increasing frequency with higher pulse rate or with the same step size, eg 1 kHz and the same pulse rate, eg 10 for all frequencies. The second setting then gives a frequency cycle of 13.3 s. Both the step size and the number of pulses are again freely selectable quantities. These explanations also apply analogously to the pulse width mode or for the second mode of operation.

In Fig.12 and Fig.13 symmetrical voltage curves are shown. The corresponding current and flow curves are then analogous to 11B ,

In Fig.14 and Fig.15 asymmetrical voltage curves are shown. The corresponding current and flow characteristics are again analogous to 11B ,

The third operating mode, in the form of a magnetic flux mode, includes the combination of the two aforementioned first and second modes (frequency mode and pulse width mode) with the aim of keeping the magnetic flux Φ constant: $$\mathbf{\Phi \_mode\; variable\; at\; f\; and\; PW\; variable}$$

With increasing frequency and constant pulse width, the current through the induction coil 56 and thus also the magnetic flux decreases. In order to keep the magnetic flux constant, therefore, the pulse width or pulse width is increased so that the current flowing through the induction coil 56 remains constant with increasing frequency.

All defaults can be set via any arbitrary time or pulse rate constants either manually (by means of a keyboard, for example) or automatically (for example, by means of the control or the control).

As described above, the apparatus 1 includes a generator 2 having at least one induction coil 56 for generating an electromagnetic field with alternating current in the form of preferably periodic oscillation functions, preferably generating and applying periodic oscillation functions with a trapezoidal current profile.

Positive and negative values of the oscillatory functions over the respective half-period are preferably not in any defined relationship to one another. The voltage present at the output of the generator 2 is preferably generated in the form of quadrilateral pulses. The current flowing through the induction coil 56 is preferred a symmetrical trapezoidal shape. The time relationship between the dynamic pulse progression (falling and rising edge) and the static pulse progression (parallel to the time axis) is freely adjustable. The trapezoidal current pulses are preferably generated as individual pulses without additional frequency modulation. The freely adjustable frequency range is preferably between 5 kHz and 15 kHz.

The generator 2 operates in the first mode "frequency mode" at a constant pulse width and according to the second mode "pulse width mode" at a constant frequency. The frequency and the pulse width can be mutually dependent according to the third mode of operation so that the magnetic flux remains constant. The limit values for all operating modes are freely adjustable via the operating device 40. All. Time constants required for the individual operating modes are likewise freely adjustable via the operating device 40. The signal curves are symmetrical or asymmetrical. The processes can be carried out with a variable number of pulses or with a constant number of pulses. For this purpose, the generator 2 has a freely programmable control by the operating device 40. The programmable controller is implemented in a microprocessor 44.

A controlled by the microprocessor 44 as described above generator 2 is therefore used to provide in an inductive point and / or rail heating device 1 for attachment to a rail 8 or a switch 10 provided inductors 6 with alternating current, by the microprocessor 44 controlled or regulated generator 2, the frequency f and / or the pulse width PW of the excitation alternating current of the inductors 6 changed.

1. a) einem von einer Wechselspannungsquelle gespeisten Generator 2,
2. b) einer Leitungsverbindung 22 zwischen dem Generator 2 und wenigstens einem wenigstens eine Induktionsspule 56 enthaltenden Induktor 6 zur Versorgung der wenigstens einen Induktionsspule 56 mit von dem Generator 2 erzeugten Wechselstrom, und mit
3. c) einer Steuerungs- oder Regelungseinrichtung 40, 44, 48 zur Steuerung oder Regelung der elektrischen Leistung des Generators 2 durch Variieren der Frequenz f und/oder der Pulsweite PW des in die Induktionsspule 56 eingespeisten Wechselstroms
4. d) für eine Induktive Weichen- und/oder Schienenheizvorrichtung 1 verwendet, bei welcher der wenigstens eine Induktor 6 an einer Schiene 8 und/oder an einer Weiche 10 eines Schienennetzes angeordnet ist und bei welcher aufgrund der mit dem Wechselstrom gespeisten Induktionsspule 56 in der Schiene 8 und/oder in der Weiche 10 durch elektromagnetische Induktion ein Strom induziert wird, welcher die Schiene 8 und/oder die Weiche 10 erwärmt.

In other words, an in Figure 8a in general overview induction device with at least

1. a) a generator 2 fed by an AC voltage source,
2. b) a line connection 22 between the generator 2 and at least one at least one induction coil 56 containing inductor 6 for supply the at least one induction coil 56 with alternating current generated by the generator 2, and with
3. c) a control or regulating device 40, 44, 48 for controlling or regulating the electrical power of the generator 2 by varying the frequency f and / or the pulse width PW of the fed into the induction coil 56 alternating current
4. d) is used for an inductive point and / or rail heating device 1, wherein the at least one inductor 6 is arranged on a rail 8 and / or on a switch 10 of a rail network and in which due to the induction coil 56 fed with the alternating current in the rail 8 and / or in the switch 10 by electromagnetic induction, a current is induced, which heats the rail 8 and / or the switch 10.

LIST OF REFERENCE NUMBERS

1

contraption

2

generator

4

electrical circuit

6

inductor

8th

rail

10

switch

12

outer side surface

14

inner side surface

16

Rail middle part

18

rail

20

railhead

22

interconnectors

24

turns

26

support body

28

magnetic field lines

30

clip

32

first leg

34

second leg

36

bulge

38

shielding

40

operating device

42

adjustment

44

microprocessor

46

display

48

sensors

50

signal line

52

final stage

56

induction coil

Claims (23)

Inductive point and / or rail heating device (1) comprising at least one generator (2) powered by an AC voltage source, which via a line connection (22) at least one at least one induction coil (56) containing, for attachment to the rail (8) or at Soft (10) provided inductor (6) supplied with alternating current, wherein due to the supplied with the alternating current induction coil (56) of the inductor (6) in the rail or in the switch by electromagnetic induction, a current is induced, which the rail (8) or the switch (10) heated, characterized in that a control device (40, 44) or a control device (40, 44, 48) for controlling or regulating the electric power of the generator (2) by varying the frequency (f) and / or the pulse width (PW) of the alternating current fed into the at least one inductor (6) is provided. Inductive point and / or rail heating device according to claim 1, characterized in that the generator (2) by the control device (40, 44) or the control device (40, 44, 48) is controlled or regulated such that the frequency (f) of the at least one inductor (6) fed AC current within a range of 5 kHz to 15 kHz is variable or adjustable. Inductive point and / or rail heating device according to one of the preceding claims, characterized in that the generator (2) is formed without a resonant circuit or without a resonant circuit. Inductive point and / or rail heating device according to one of the preceding claims, characterized in that the control device (40, 44) or the control device (40, 44, 48) includes at least one microprocessor (44), the frequency (f) via drivers and / or the pulse width (PW) of the alternating current fed into the at least one inductor (6) varies or sets. Inductive point and / or rail heating device according to claim 4, characterized in that the control device (40, 44) or the control device (40, 44, 48) comprise an operating device (40), via which operating parameters of the generator (2) by the microprocessor (44) are adjustable. Inductive point and / or rail heating device according to claim 4 or 5, characterized in that in the microprocessor (44) algorithms for controlling or regulating the power of the generator (2) by varying the pulse width (PW) and / or frequency (f) of the alternating current fed into the at least one inductor (6) are implemented, the control or regulation taking place depending on at least one reference variable. Inductive point and / or rail heating device according to claim 6, characterized in that the at least one reference variable for the control or regulation of the power of the generator (2) includes at least the ambient temperature or the rail / switch temperature, each alone or in combination with the humidity , Inductive switches and / or Schienenheizvorrichtung according to claim 7, characterized in that provided at least one sensor (48) for measuring the reference variable and is connected in a signal conducting manner to the microprocessor (44). Inductive point and / or rail heating device according to claim 8, characterized in that in the microprocessor (44) implemented algorithms for the control or regulation of the power of the generator (2) a temperature range between a lower temperature limit (Tu) and an upper temperature limit (To) for the ambient temperature and / or for the rail / switch temperature is predetermined, wherein d) at an ambient temperature and / or rail / switch temperature measured by the at least one sensor (48), which is in the range between the upper temperature limit (To) and the lower temperature limit (Tu), by the microprocessor (44); a regulation of the electric power of the generator (2) depends on the ambient temperature and / or depending on the rail / vane temperature as a reference variable, and e) at a measured ambient temperature and / or rail / switch temperature which is greater than or equal to the upper temperature limit (To), the electric power of the generator (2) is set to zero or a minimum value, and f) at a measured ambient temperature or rail / vane temperature which is less than or equal to the lower temperature limit (Tu), the electric power of the generator (2) is set to a constant maximum value. Inductive point and / or rail heating device according to claim 9, characterized in that in the microprocessor (44) from a mean temperature (Tav), which represents a middle of the range between the upper temperature limit (To) and the lower temperature limit (Tu) , either in the direction of the upper temperature limit (To) or in the direction of the lower temperature limit (Tu) different algorithms for the control or regulation of the power of the generator (2) are implemented. Inductive point and / or rail heating device according to claim 9 or 10, characterized in that the control device (40, 44, 48) includes a P-controller implemented in the microprocessor (44), a PI controller or a PID controller. Inductive point and / or rail heating device according to one of the preceding claims, characterized in that at least one display (46) is provided for the representation of operating parameters. Inductive point and / or rail heating device according to one of claims 5, 9, 10 or 12, characterized in that the operating parameters, the pulse width (PW) and / or frequency (f) of the at least one inductor (6) fed AC and / / or the upper temperature limit (To) and the lower temperature limit (Tu) and / or the mean temperature (Tav). Inductive switches and / or Schienenheizvorrichtung according to any one of the preceding claims, characterized in that the inductor (6) is plate-shaped, with a small relative to the dimension of its side surfaces thickness. Inductive point and / or rail heating device according to claim 14, characterized in that the windings (24) of an induction coil (56) of the at least one inductor (6) are arranged in a single plane. Inductive point and / or rail heating device according to claim 14 or 15, characterized in that the turns (24) of the induction coil (6) of the at least one inductor (6) are received in or from a plate-shaped support body (26), which with one of his Side surfaces for attachment to an inner side surface (14) or on an outer side surface (12) of a central part (16) of a rail (8) is provided. Inductive point and / or rail heating device according to one of claims 14 to 16, characterized in that the at least one inductor (6) by means of a fastening device (30) is fixed to the rail (8), wherein the fastening device (30) and the inductor (6) at least one shielding body (38) of electrically non-conductive, but magnetically conductive material such as ferrite is interposed. Inductive point and / or rail heating device according to one of claims 14 to 17, characterized in that the at least one inductor (6) by means of an L-shaped bracket (30) is fixed to the rail (8), wherein the L-shaped bracket (30) has a first leg (32) at least partially encompassing a rail foot (18) and a second leg (34) holding the inductor (6) on a side face (12, 14) of the rail (8), the second leg ( 34) of the clip (30) and the inductor (6) at least one shielding body (38) of electrically conductive, but magnetically non-conductive material such as ferrite is interposed. Inductive point and / or rail heating device according to one of the preceding claims, characterized in that the generator (2) is controlled such that after switching on the generator (2) the pulse width (PW) at a constant frequency (f), starting from a starting value (PW ₀ ) for the pulse width (PW) over a certain period of time (tr) increases ramped to a relation to a continuous power value of the generator (2) corresponding pulse width (PW ₂ ) higher value (PW ₁ ), then for a further period (t1 ) (in this increased value PW ₁₎ is kept constant, and (after the further time period t1) to (the continuous output value of the generator 2) corresponding pulse width (PW ₂₎ is lowered. Rail network for rail vehicles, including at least one rail and / or a switch, characterized in that it is an inductive Switch and / or rail heating device (1) according to one of the preceding claims includes. Rail network according to claim 20, characterized in that at least one inductor (6) is arranged on one or both side surfaces (12, 14) of at least one rail (8). Rail network according to claim 21, characterized in that the at least one inductor (6) is arranged on the rail (8) in a rail section located in the region of a switch (10). Use of an induction device with at least a) a generator (2) powered by an AC voltage source, b) a line connection (22) between the generator (2) and at least one at least one induction coil (56) containing inductor (6) for supplying the at least one induction coil (56) with the generator (2) generated AC, and with c) a control or regulating device (40, 44, 48) for controlling or regulating the electric power of the generator (2) by varying the frequency (f) and / or the pulse width (PW) of the alternating current fed into the induction coil (56) d) for an inductive point and / or rail heating device (1), wherein the at least one inductor (6) on a rail (8) and / or on a switch (10) of a rail network is arranged and in which due to the AC-fed induction coil (56) in the rail (8) and / or in the switch (10) by electromagnetic induction, a current is induced, which heats the rail (8) and / or the switch (10).

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