EP2463174A1 - Method and device for replacing a bulb of a light signal - Google Patents

Abstract

The device for creating a replacement of an incandescent lamp by a lighting unit for a light signal in rail traffic that is in an interlocking side of safety monitoring, comprises: lighting units such as LED lights with a power supply interface; an interlocking side interface (8) to subscribe the electric power from a signal box; and an interface module interposed between the interlocking side interface and the power supply interface, where the interface module comprises a control logic (24), which knows a signal aspect and/or a daily time-dependent characteristic of the incandescent lamp. The device for creating a replacement of an incandescent lamp by a lighting unit for a light signal in rail traffic that is in an interlocking side of safety monitoring, comprises: lighting units such as LED lights with a power supply interface; an interlocking side interface (8) to subscribe the electric power from a signal box; an interface module interposed between the interlocking side interface and the power supply interface, where the interface module comprises a control logic (24), which knows a signal aspect and/or a daily time-dependent characteristic of the incandescent lamp to be replaced and controls the power output of the power supply interface as a function of the selected signal aspect and/or daily time; a voltmeter (30) measuring the interlocking-side at the interface and the voltage applied to the control logic; and a power receiver that controls the time measured by the control logic in dependence of the voltage so that the interlocking side interface replicates the characteristic of the power consumed to replace incandescent lamp. The voltmeter operates in tycom readiness management system mode. The power receiver has a power driver in pulse-width modulation (PWM) mode, and eliminates typical inrush current in response to the interlocking-side switching present on the lamp for a cold filament in the lamp. The power receiver eliminates the inrush current in a: first temporal portion of a temporary parallel resistance after providing the electrical power for switching on the lighting unit, where the parallel resistance corresponds to the resistance of the incandescent lamp in the cold filament and the resistance value increases with time; and second temporal portion of the temporary parallel resistance replaced by a PMW-function to simulate the load characteristics of the lamp. An independent claim is included for a method for creating a replacement of an incandescent lamp by an energy efficient lighting unit for a light signal in rail traffic.

Description

The present invention relates to an apparatus and a method for implementing a replacement of an incandescent lamp by a more energy-saving light source for a light signal in rail-bound traffic, which is involved in an interlocking safety monitoring.

As before, light signals for the control of traffic flows, in particular for the control of rail-bound traffic, is of paramount importance, even if, for example, in railway engineering standards now exist that transmit train control exclusively due to radio transmission in the cab of a locomotive or a control car Provide information (ETCS Level 2 and above).

Such light signals are currently still equipped to a large extent with conventional light bulbs. However, the limited life of such bulbs represents a very high risk to the safety of traffic, because non-luminous signal points can distort the actually signal to be displayed dangerous. For this reason, stand for the control of the function of the incandescent bulbs above all things such measures that can close from the usually absorbed by a light bulb lamp current to the proper function of the same. By nature, however, there is a considerable potential for failure in this type of monitoring because, for example due to parasitic leakage currents due to the sometimes very long cable routes to current flows that have nothing to do with the illumination of the actual signal lamp.

Likewise, a significant (personal) risk typically also result from the process of lamp replacement, because often here in the dark, bad weather conditions and sometimes under significant Time pressure has to be worked. Especially in mountainous areas, the accesses to the light signals are sometimes quite exposed, for example on viaducts or before and after tunnels. Due to the increasing automation of control and interlocking technology many stations are no longer busy today, resulting in the event of a disruption that the access routes to remedy the defect are longer and thereby both the control period resp. the delay minutes increase as well as the costs for the elimination of the disturbance increase.

In US 2004/0070519 A1 "Compact light emitting diode retrofit lamp and method for traffic signal lights" is a signal light disclosed in which incandescent bulbs are replaced by LED bulbs. In this case, Fresnel lenses are used for optical adjustment. The LED bulbs already contain their own energy supply.

Due to the significantly longer life of LED bulbs and due to the fact that the filament light bulbs will disappear completely from the market in the medium to long term, is therefore increasingly transferred to equipment / retrofit of new or existing signal systems to use LED bulbs. These LED bulbs often have a greater number of individual LEDs arranged in an array that are collectively lit to indicate a signal term. The failure of a single LED or a small number of individual LEDs can hardly fall due to the large number of points of light weight, which is why in addition to the incandescent lamps increased life of the LED and the system error rate is significantly lower.

However, the problem with retrofitting existing signals is that the new LED bulbs are not compatible with the incandescent bulbs and, as a rule, high costs are incurred for the creation of new signals and the existing signal structure at least partly to be scraped. It should also be borne in mind that the connection from the interlocking, and to a large extent relay interrupters are affected, does not tolerate replacement of filament lamp with LED lamp due to the very different characteristics of filament lamp and LED lamp. Especially the relay interlockings are comparatively precisely matched to the characteristics of the previously used filament lamps to meet safety statements of quality SIL4 can. However, interventions in the control unit-side control hardware are very complex and costly, so that this boundary condition can become the co-criterion for replacing filament lamps with LED lamps.

The present invention is therefore based on the object of specifying a device for implementing a replacement of a light bulb by a more energy-saving light source for a light signal in rail-bound traffic, which is included in a safety-related monitoring. In this case, a replacement of filament lamps by LED bulbs or similar bulbs can be done in a simple and cost-saving manner without a Stellwerkseitigen hardware conversion.

1. a) eine Anzahl von Leuchtmitteln, insbesondere LED-Leuchten, mit einer Leistungsversorgungsschnittstelle, wobei die Anzahl von Leuchtmitteln zur Erzielung einer der Glühlampe analogen Leuchtstärke weniger elektrische Leistung benötigt als die zu ersetzende Glühlampe;
2. b) eine stellwerkseitige Schnittstelle zum Bezug von elektrischer Leistung aus dem Stellwerk;
3. c) ein Interface-Modul, das zwischen die stellwerkseitige Schnittstelle und die Spannungsversorgungsschnittstelle geschaltet ist, wobei das Interface-Modul
   • c1) eine Steuerlogik umfasst, welche eine signalbegriffs- und/oder tageszeitabhängige Kennlinie der zu ersetzenden Glühlampe kennt und die Leistungsabgabe an die Leistungsversorgungsschnittstelle in Abhängigkeit von dem gewählten Signalbegriff und/oder der Tageszeit steuert;
   • c2) einen Spannungsmesser umfasst, der die an der stellwerkseitigen Schnittstelle anliegende Spannung misst und an die Steuerlogik übermittelt;
   • c3) einen Leistungsaufnehmer umfasst, der von der Steuerlogik in Abhängigkeit von der gemessenen Spannung so gesteuert wird, dass die an der stellwerkseitigen Schnittstelle aufgenommene Leistung die Kennlinie der zu ersetzenden Glühlampe nachbildet.

This object is achieved according to the invention by a device for realizing a replacement of an incandescent filament lamp by a more energy-saving illuminant for a light signal in rail-bound traffic, which is included in a safety-related monitoring on the side of the cage. This device comprises the following components:

1. a) a number of lighting means, in particular LED lights, with a power supply interface, wherein the number of lighting means for obtaining a luminous intensity analogous to the incandescent lamp requires less electrical power than the incandescent lamp to be replaced;
2. b) an interface-side interface for the purchase of electrical power from the interlocking;
3. c) an interface module that is between the Stellwerkseitige Interface and the power supply interface is connected, the interface module
   • c1) comprises a control logic which knows a signal concept and / or time of day dependent characteristic of the bulb to be replaced and controls the power output to the power supply interface in dependence on the selected signal term and / or the time of day;
   • c2) comprises a voltmeter which measures the voltage applied to the inter-processor interface and transmits it to the control logic;
   • c3) comprises a power sensor, which is controlled by the control logic in dependence on the measured voltage so that the recorded power at the inter-power interface emulates the characteristic of the bulb to be replaced.

In this way, with the device and the method according to claim 8, it is possible to insert an LED illuminant as a replacement for an incandescent filament lamp into the light signal in such a way that no sign of it is taken in the signal box. The voltage measurement helps to equalize the power consumption of the entire device with the switched LED bulbs of the power consumption of the conventional filament lamp. Since the control logic has precise knowledge of the various situation-specific characteristics of the filament lamp to be replaced, it is possible to be able to understand the characteristic at the interlocking interface with sufficiently small time constants to a supposed error response in the interlocking, in particular in a very sensitive to currents relay relay, safe to exclude.

The requirement of real-time adaptation of the power consumption to the predetermined characteristic can be fulfilled particularly well when the voltmeter operates in the TRMS mode. Then already suffice over half a period of the power supply averaged square sums of Power supply (input voltage) to set the power balance according to the intended characteristic curve.

The required speed of the power adjustment is recordable especially well if the power sensor includes a power driver in PWM mode. Of course, the power sensor, the still available, not consumed by the LED bulbs energy supply an energy storage. However, as soon as electrical energy has to be destroyed, this is done with a load resistor controlled in PWM mode in a manner that is particularly close to real-time.

The device must meet very special requirements if the characteristic of the cold filament must be reproduced. For a cold filament, the electrical resistance is initially much lower than in the following operation. In the case of a 40-volt filament lamp, this value is around 9 ohms at the start of the switch-on and then rises to a value in the range of approximately 68 ohms over an interval of approximately 70 ms. For this reason, it is particularly advantageous if the power sensor in response to the Stellwerkseitige turning on the light bulb can destroy a typical for a cold filament in the incandescent lamp inrush current. A preferred approach for this purpose can be realized, for example, by the power sensor can drain the inrush current by means of a temporarily parallel resistor corresponding to the resistance of the incandescent lamp with cold filament, the resistance value then preferably over time (in relatively short time ).

An alternative approach for this purpose may provide in a further advantageous embodiment of the invention that the power sensor in a first temporal portion after the Stellwerk side providing the electrical power to turn on the light source by means of a temporally connected in parallel Resistance corresponding to the resistance of the filament lamp when the filament is cold, and in a second subsequent section the parallel resistor is replaced by a PMW function to simulate the load characteristic of the filament lamp. In this way, for example, in the first milliseconds after switching on the luminous means, a resistor of suitable size can be switched as a load, which is subsequently replaced by a load simulated with the PMW function.

Special requirements for the faithful reproduction of the load of the filament lamp as realistic as possible results when the network operator uses the signal term of a flashing signal. Here, there is a problem that the characteristic for the filament lamp deviates from the characteristic curves during the first switching on during the blinking operation, because the filament no longer fulfills the characteristics of the cold filament during the blinking operation at the time of switching on. A preferred development of the invention therefore provides for connecting the power sensor for a flashing mode of the luminous means with a resistor for simulating the switch-on load, in particular in the first milliseconds, which is adapted to the state of the warm filament as a result of the flashing operation.

• Figur 1 in schematischer Darstellung die heutige Anschaltung einer 40 V Glühlampe aus herkömmlichen Relaisstellwerken, beispielsweise Do67 und Do69-Stellwerke der Siemens Schweiz AG;
• Figur 2 in schematischer Darstellung die heutige Anschaltung der 40 V Glühlampe bei Vorsignalen mit in Serie geschalteten Glühlampen aus herkömmlichen Relaisstellwerken;
• Figur 3 in schematischer Darstellung eine Serienschaltung eines Interface-Moduls für die Ansteuerung eines LED-Leuchtmittels aus herkömmlichen Relaisstellwerken;
• Figur 4 in schematischer Darstellung das Prinzip der Messkette mit Rückführung, nach welchem das Interface-Modul arbeitet;
• Figur 5 in schematicher Darstellung das Messprinzip und das Messintervall für die Eingangsspannungsmessung am Eingang des Interface-Moduls;
• Figur 6 in schematischer Darstellung die Anschaltcharakteristik und die Kennlinienregelung der Lastansteuerung;
• Figur 7 in schematischer Darstellung eine PWM-Ansteuerung der Last;
• Figur 8 in schematischer Darstellung eine Inrush-Lösung mit Analogtechnik;
• Figur 9 in schematischer Darstellung eine Serienschaltung von Interface-Modulen bei in Serie geschalteten LED-Leuchtmitteln;
• Figur 10 in schematischer Darstellung die Leistungsaufteilung zwischen Elektronik, LED und Leistungsvernichter;
• Figur 11 in schematischer Darstellung eine Prinzipschaltung des Interface-Moduls mit der Funktionalität eines Leistungsbilanzierers;
• Figur 12 in schematischer Darstellung den Aufbau und die Aufteilung der Funktionen im Interface-Modul
• Figur 13 in schematischer Darstellung das dynamische Verhalten der 40V Referenzlampe bei kaltem Glühfaden;
• Figur 14 in schematischer Darstellung den Lampenstrom beim ersten und wiederholten Einschalten der 40V-Referenzlampe bei einer 36 VDC-Quelle; und
• Figur 15 in schematischer Darstellung den Lampenwiderstand beim ersten und wiederholten Einschalten der 40V-Referenzlampe bei einer 36 VDC-Quelle.

Preferred embodiments of the present invention would be explained in more detail with reference to the drawing, for example. Showing:

• FIG. 1 a schematic representation of today's connection of a 40 V incandescent lamp from conventional relay interlockings, such as Do67 and Do69 interlockings of Siemens Switzerland AG;
• FIG. 2 in a schematic representation of today's connection of the 40 V incandescent lamp with presignals with series-connected incandescent lamps from conventional relay interlockings;
• FIG. 3 a schematic representation of a series connection of an interface module for controlling an LED bulb from conventional relay interlockings;
• FIG. 4 a schematic representation of the principle of the measuring chain with feedback, according to which the interface module works;
• FIG. 5 a schematic representation of the measuring principle and the measuring interval for the input voltage measurement at the input of the interface module;
• FIG. 6 a schematic representation of the turn-on and the characteristic control of the load control;
• FIG. 7 a schematic representation of a PWM control of the load;
• FIG. 8 a schematic representation of an inrush solution with analog technology;
• FIG. 9 a schematic representation of a series connection of interface modules in series-connected LED bulbs;
• FIG. 10 a schematic representation of the power distribution between electronics, LED and power killers;
• FIG. 11 a schematic diagram of a basic circuit of the interface module with the functionality of a Leistungsbisanzierers;
• FIG. 12 a schematic representation of the structure and distribution of functions in the interface module
• FIG. 13 in a schematic representation the dynamic Behavior of the 40V reference lamp with cold filament;
• FIG. 14 schematically the lamp current at the first and repeated switching on the 40V reference lamp at a 36 VDC source; and
• FIG. 15 schematically the lamp resistance at the first and repeated switching on the 40V reference lamp at a 36 VDC source.

The basic functionality of an LED signaling device is the optical signaling for the railway driver. The requirements of the approval must be interpreted correctly and the valid applicable standards and, if applicable, specifications of the operator for light intensity, emission characteristics, color location of the emitted light and other parameters and properties to be met.

In order to produce compatibility with an incandescent lamp, the electrical parameters and, in some cases, the mechanical parameters of the actual illuminant must match. For the realization of an interface module IM from a 40V / 20W incandescent lamp to currently a 12V / 10W LED, it is crucial to know the mode of operation for the adjustment of the lamp currents as well as the voltage curve u = f (t) of the filament lamp. The tolerances from the side of a (relay) interlocking as well as the environmental influences play an important role.

• Elektrische Schnittstelle 8 zum Stellwerk (40V AC Schnittstelle oder AC gleichgerichtet)
• Elektrische Schnittstelle 10 zum LED-Lichtpunkt (12V/10W Schnittstelle)
• Mechanische Schnittstelle (Montage Ort, Montageart etc.)
• Diagnose bzw. Projektierungsschnittstelle.

The interface module IM has at least three interfaces to the overall system signal box signal:

• Electrical interface 8 to the interlocking (40V AC interface or rectified AC)
• Electrical interface 10 to the LED light point (12V / 10W interface)
• Mechanical interface (installation location, mounting method, etc.)
• Diagnostics or configuration interface.

FIG. 1 shows a schematic representation of today's connection of a 40 V filament lamp 2 from conventional relay interlocks 4, such as Do67 and Do69 interlockings of Siemens Switzerland AG. The FIG. 2 shows this today's connection of the 40 V filament lamp 2 in pre-signals with series-connected filament lamps from conventional relay interlocks. 2 FIG. 3 now shows a schematic representation of a series connection of an essential to the invention interface module IM for controlling an LED bulb 12 from conventional relay interlocks 4. The interface module IM is located here advantageously directly to the LED bulb 12 and is in a track cable 14 from Interlocking 4 to the LED bulb 12 interposed.

• Spannungs- und Leistungsmessung für alle möglichen Kurvenformen
• in Abhängigkeit der Spannungsmessung muss durch eine funktionale Verknüpfung im Interface-Modul IM eine ohmsche Last (variabel) dazugeschaltet werden

The required replica of the UI characteristic of the previously used 40V filament lamp 2 is a must, because before the characteristic curve can be reproduced by the interface module IM, the voltage as a real RMS value (such as filament lamp) can be detected. The challenges for the characteristic simulation are:

• Voltage and power measurement for all possible waveforms
• Depending on the voltage measurement, a resistive load (variable) must be added via a functional link in the interface module IM

The sequence of the load connection (load control) is in FIG. 4 shown. The feedback involves the risk that an excessive load change in connection with the control time can produce a tendency to oscillate. A suitable approximation algorithm reduces the tendency to oscillate and allows realization. One possible implementation of this is in FIG. 5 shown. A possible realization variant too FIG. 5 for the start-up of the LED bulb 12, a 9 ohm resistor would be parallel to the start-up behavior in the first 5 ms as a load switch and then to simulate the load with a PWM function.

The reproduction of the dynamic characteristic is an important necessary component of the substitution of LED electronics in the relay interlockings 4. It is particularly significant that the inrush current (starting current increase of the cold lamp) for the proper functioning (tightening the serially operated in the lamp current path relay with switching of the contacts) (train protection relay ZU or ZK relay) is required.

The replica of the so-called "dynamic characteristic curve" is a very demanding task, because it has to be monitored relatively accurately due to the safety-related short response times of the control unit's monitoring. The FIGS. 13 to 15 The dominant parameters show an example of a 40V filament lamp 2 used by the Swiss Federal Railways.

When using analog circuit technology, the task is that the first time a load resistance of about 9 ohms (to achieve an inrush current) must be continuously changed to> 50 ohms within 70ms. One possible solution is the FIG. 8 refer to.

However, if the LED electronics are switched on and off every second (flashing mode), the load resistance changes from 68 ohms to approx. 20 ohms (see FIG. 15 ). There is almost no logic voltage available at the 9 ohm load for a few milliseconds; it is rather for the FPGA resp. CPU power supply needed. In the implementation variant with analog circuit technology, a sufficiently good accuracy is achieved when using components of low tolerance for C and the FETs. FIG. 7 shows a solution in accordance with digital circuit technology, in which the load is controlled in PWM function to set the desired characteristic.

• Genauigkeitsanforderung für Tag bzw. Nachtspannungsbereich von < ± 5 %
• Stabiles Verhalten bei kurzzeitigen Änderungen
• Schutz vor Überlast
• Im Fehlerfall wird der Leistungsbilanzierer gezielt abgeschaltet.

Symmetrization (the series cascading of interface modules as in FIG. 9 shown) has been implemented under the following aspects:

• Accuracy requirement for day or night voltage range of <± 5%
• Stable behavior with short-term changes
• Protection against overload
• In the event of an error, the power balancer is switched off in a targeted manner.

The FIG. 10 shows the current balance to be reached (Leistungsbisanzierers) of the interface module IM, so that a series circuit (see FIG. 9 ) of several interface modules is possible. The accuracy to be achieved is less than ± 3-5% due to the series voltage. When the interface module IM is switched on for the first time, an identically large current of a light bulb is generated (see characteristic cold thread with an initial resistance of approx. 10 Ohm according to FIG. 13 ). For example, this guarantees that Domino signal boxes from Siemens Schweiz AG ensure that all relay coils connected in series are correctly connected.

The power balancer used in the interface module IM can be simplified as a control element. The FIG. 11 shows the functional principle. The voltage of the interface module IM can be represented as a current source with fixed parallel resistors and a variable resistor 16 (power balance with PWM). The power loss of the fixed loads (electronics ie FPGA or CPU, power consumption of the LED, etc) are simulated by resistors. The power balancer varies in the equivalent circuit, the power loss by a change in resistance.

The formula above gives the power consumption / power balance. In order to be able to configure the power consumption for the type of LED construction used, a service or engineering interface 18 is provided, as in FIG FIG. 12 shown. This interface makes it possible to operate LED's with the appropriate type of power source (eg 1000mA, 500mA, 350mA etc.). The FIG. 12 shows a possible realization. If highly efficient LED's are driven, the resulting larger unneeded line is detected by the power balance and converted into heat at a corresponding resistor 20 or used as an example for the charge of secondary cells.

The realization of the power consumer is mainly determined by the speed of the required change. In order to keep vibration tendencies in the lighting system as small as possible, the power consumer is realized with PWM and a change interval of about 10 to 50 ms.

The flashing signal lamp is a special case at the Swiss Federal Railways. This type of signaling makes it possible to maintain railway operation with performance losses if one yarn fails. With the so-called Fusi flashing the signal lamp (emergency stop lamp) with 1Hz and the clock ratio of 1: 1 is controlled by the relay interlocking. For the simulation of this flashing at the Domino interlockings, the dynamic characteristic of the filament yarn lamp according to the Figures 14 and 15 considered.

The power measurement of the interface module IM is highly dependent on the accuracy of the input voltage measurement. When the input voltage is measured with sufficient accuracy The interface module IM can reliably switch the load control via PWM or similar methods.

The failure behavior of the interface module IM simulates the behavior of the incandescent lamp as well and reliably as possible. The switch-on behavior also reliably bridges the failure simulation. The inertia is achieved with good repeatability. The failure behavior can be simulated on the one hand by a reactivatable fuse or by a targeted load shedding.

The heat dissipation is not easy to realize according to the experience of many years of hardware projects and is usually underestimated. In order to achieve a sufficiently good convection, as large an area as possible is used. A viable solution is the use of the existing metal housing of the signal lamp to distribute the heat.

• Widerstand an Gehäuse der Signallampe
• Abgeschaut von der Induktionskochplatte würde ein Prinzip von Wirbelströmen eine sehr gute Wärmeableitung ermöglichen. Dazu sollte das Gehäuse der Signallampe die Wirbelströme in Wärme umwandeln.

The following ideas could also be used:

• Resistance to housing of the signal lamp
• Looking down from the induction hotplate, a principle of eddy currents would allow very good heat dissipation. For this purpose, the housing of the signal lamp should convert the eddy currents into heat.

In the case of a series connection of two or three lamps, a short circuit on the intact light source causes considerable overvoltage, which must be controlled in the light sources. The clarifications of the signal circuits show that an overvoltage of 20% can be reliably detected and controlled in a defined period of time.

Starting from the basic principle of the light bulb that electrical energy is converted into light and heat, first the physical conditions and Properties shown exactly. Due to the fact that the signal form from the lamp supply can contain up to 30% harmonic components, the detection of the voltage will take this into account. Derived from the implementation of the interface module IM, this means that a robust measuring principle must be used.

• Nulldurchgangsdetektion
• Effektivbewertung mit Gleichrichter
• Mittelwertbildung über Perioden (einzelne oder mehrere)

Based on these experiences, the following principles are not used:

• Zero crossing detection
• RMS evaluation with rectifier
• Averaging over periods (single or multiple)

• Integration von Zeitwerten (Diskrete Integration von Werten)
• Bildung von (T)RMS Werten
• Analoge Integration mit Operationsverstärker

Derived from the principle of the light bulb, it is advisable to "temporal integration" over one or two periods. The following principles can be used for the realization:

• Integration of time values (discrete integration of values)
• Formation of (T) RMS values
• Analog integration with operational amplifier

±5%. gering 03 Effektivwert $$\mathit{eff}=\sqrt{\frac{1}{S}*{\displaystyle \sum _{\iota =1}^S}{U}_{\iota }^2}$$

-1% bis +3% mittel Nachfolgend wird aufgezeigt, wie aus einem gleichgerichteten Sinussignal mit maximal 35% harmonischem Anteil (bis zur 20. Oberwelle) die Eingangsspannung ermittelt werden kann. Die einzelnen Varianten wurden jeweils mittels eines Mathlabskripts geprüft, und die Messgenauigkeit bestimmt. In den nächsten Unterkapiteln werden die folgenden Variabeln verwendet:

• U_i: Spannungswert
• S: Anzahl Samples pro Halbwelle

The selection of the principle is carried out according to the following table. No. description Calculation algorithm measurement accuracy Integration effort (VHDL) 01 Peak detection peak = max ( measured values ) ± 10%. low 02 Moving average $$\mathrm{mean}=\frac{1}{S}*{\displaystyle \underset{\iota =1}{\overset{S}{\Sigma }}}{U}_{\iota }$$

± 5%. low 03 RMS $$\mathit{eff}=\sqrt{\frac{1}{S}*{\displaystyle \underset{\iota =1}{\overset{S}{\Sigma }}}{U}_{\iota }^2}$$

-1% to + 3% medium The following section shows how the input voltage can be determined from a rectified sine signal with a maximum of 35% harmonic component (up to the 20th harmonic). The each variant was tested by means of a Mathlabskripts, and the measurement accuracy determined. The following subchapters use the following variables:

• U _i : voltage value
• S: number of samples per half-wave

In peak detection, a peak value is determined for each half-wave. This is a very simple method of voltage measurement. For the implementation, a low-pass filter is necessary, which brings a certain damping already from the first harmonic. The filter can be implemented digitally. In addition, a comparator (8 x 8 bits), a little logic and a register in which the instantaneous peak value is stored are necessary. The accuracy of the voltage measurement achieved here at a 35% harmonic content about ± 10%, which is almost robust.

A very simple algorithm for detecting the input voltage is the calculation of the sum of the individual voltage measurements and their averaging over a half-wave. To compensate for differences between the positive and negative half wave, this value should be averaged over at least two half waves as follows: $$\mathit{mean}=\frac{1}{S}*{\displaystyle \underset{i=1}{\overset{S}{\Sigma }}}{U}_i$$

This calculation can be implemented very easily, for example on an FPGA. It is just an adder (about 16 x 8 bit, depending on S) and some logic necessary. The division can be done by a clever choice of S (S ∈ {2 ⁿ }) by means of a bit shift operation. An analogue low-pass filter in front of the rectifier is recommended, so that high-frequency signal components are not measured. With a 35% harmonic content, the measurement accuracy with this method is approx. ± 5% and is about twice as accurate as the previous one. However, the evaluation of two half-waves are required for this accuracy (ie 20 ms at 50 Hz).

The determination of the input voltage in the calculation of the RMS value is somewhat more complicated. Here, the root of the quadratic sum of the input voltage averaged over all measured values of a half-wave is calculated. This result should also be averaged over both half-waves of a sine wave. $$\mathit{eff}=\sqrt{\frac{1}{S}*{\displaystyle \underset{i=1}{\overset{\mathrm{<figure-callout\; id="2"\; label="S\; U\; i"\; filenames="imgf0007.png,imgf0008.png"\; state="\{\{state\}\}">S\; </figure-callout>}}{\Sigma }}}{U}_i^{}{}_2^{}}$$

For calculating the sum of squares, a multiplier (about 8 x 8 bits) and an adder (about 22 x 16 bits, depending on S) are needed. In addition, at the end of the root must be drawn from the sum. The root function can be implemented relatively space-saving in VHDL. Thus, this calculation method can also be implemented on an FPGA. Again, an analog low-pass filter should be provided for filtering high-frequency signal components. In order to be able to increase the integration density on the board (ie to select a small FPGA), the calculation of the effective value could possibly be taken over by a DSP. With a 35% harmonic content, the measurement accuracy with this method is about -1% to + 3%. If digital low-pass filters are to be used, it is advantageous to process a signal that is not rectified. A rectified signal loses through a good low-pass filter, the zero crossings and can then no longer be meaningfully evaluated.

The FIG. 12 The implementation variant shown here shows the architecture for the interface module IM without security mechanisms. The safety mechanisms to achieve approval according to EN 50129 will be separated later described. There, the various architectures to achieve the necessary error disclosure will be described. The interface module IM comprises an EMC protection 22 on the interface side interface and then has a number of function blocks controlled and monitored by a control logic 24. The control logic 24 itself has a service and configuration interface 18. A function block automatic shut-off 26 primarily deals with the case of the defective LED light source 12 and also ensures that the LED light source 12 does not glow. The functional block "internal voltage conditioning" 28 applies to the provision of the voltages required in the interface module IM, in particular the provision of a sufficient voltage for the control logic 24 in the case of the simulation of the inbrush inrush current. The function block "TRMS voltage measurement" 30 has a supporting role for the interface module IM, because only with a high quality of the measurement of the input voltage ultimately the function of the filament lamp replacement can be guaranteed in the first place. In particular, the "Inrush current automatic" function block 32 controls the time-critical process of inbrush current simulation. The function block "operating state monitoring" 34 ensures the monitoring of the operation of the interface module IM and the LED lamps 12 controlled by it. The function block "energy balancer" 36 has the task in a series circuit of interface modules IM for controlling meherer LED bulbs 12 to account for the energy absorbed per module and to adjust the interface modules IM. The functional block "current interface" 38 decides, depending on the LED illuminant 12 used, which current is delivered to the LED illuminant 12. The function block "luminous flux monitoring" 40 detects whether the LED illuminant 12 also actually lights up and also illuminates in the correct mode (for example, during the night reduction of the light output). The function block "energy shredder" 20ist placed here outside of the interface module IM, to show that the excess energy must probably be converted into heat usually outside of the interface module IM or, for example, an external or, of course, an internal energy storage is supplied.

The lamp characteristic is simulated by means of resistors at the input. One of the resistors is on during the on-time of the FPGA to simulate the regular power reference. As soon as the FPGA turns on the LEDs, the resistor is disconnected from the mains. This resistance can be controlled, for example, by the function group "inrush current automatic".

The safety consideration depends on the architecture of the interface module. The safety objectives for SIL 4 according to EN 50129 can only be achieved due to the functionality and the system limits by means of two independent elements / channels or with a special test procedure. In order to ensure the error disclosure of the light output, it is a good solution to detect this suburb directly at the LED bulbs 12 and pass two channels to the control logic 24 of the interface module IM. With regard to the operational safety and the feasibility of this interface module IM is above all that the interlocking 4 is reported back on the power reference on the basis of the light bulb criteria, whether the switched LED bulb 12 is actually lit.

On the other hand, the LED lamp 12 may not light up due to external influences, influencing voltages, etc., without activation by the signal box 4. For this purpose, a minimum glow limit in the range of those of the substituted filament lamp (the glow limit) must be maintained even in the event of a fault. At the same signal (same function group), the LED bulbs 12 must have the same light intensity within a certain tolerance. If during daytime operation a single point of light of a term, the must be represented by more than one light point, incorrectly works in the night mode, this can be perceived as too high signal concept (eg F2 → F1 or F5 * → F1 *) and would represent a serious error signal.

According to the safety-related conditions to be applied, the LED could be controlled in one channel, if a light monitoring is used as an independent viewing unit with switch-off capability. At least one absolute lower threshold must be monitored. However, a wrong day / night operating mode could not be reliably detected. Therefore, the monitoring threshold for the light intensity measurement should be dependent on the input voltage. To do this, the input voltage must be evaluated for day / night operation both in the control channel and in the monitoring channel. With continuous adjustment of the signal intensity in proportion to the input voltage, a simpler evaluation of the input voltage without true RMS calculation could possibly be used in the monitoring channel.

Alternatively, a 2-channel architecture (composite fail-safety) is possible. To compensate for tolerances, an exchange of the TRSM results between the channels must be provided. Each channel evaluates the deviation to the adjacent channel, if it is within the tolerable range, both channels continue to work with a common value. If the LED bulb 12 does not emit enough luminous flux, the monitored current window would have to be left in the interlocking 4. However, not the current reference of each individual light spot is monitored by the relay interlocking 4, but depending on the driving concept of the current reference of series circuits of multiple points of light, or points of light and equivalent resistance. This makes it difficult to reliably reveal the failure of the light point with a change in the current reference. The safety-related reaction therefore ideally consists in the complete interruption of the current path, as is the case with a filament lamp in the case of filament defect.

This raises the question of whether the shutdown must be reversible by the interface module IM so that after replacement of an LED bulb 12, the interface module IM can be put back into operation. A reversible shutdown with "reset button" is difficult to realize, however, because ideally the current path is completely interrupted and thus the interface module 12 is disconnected from the power supply. In addition, the light point is usually not switched on when replacing the LED bulb from the interlocking (except home position lamps). In addition, in the case of a reversible solution, the maintenance of the safe condition according to EN 50129 must be proven, even in the event of a fault. For this purpose, for example, a portion of the available in excess electrical power could not be reduced by the energy shredder 20, but stored in a battery, so that the interface module IM would always be sufficient for re-booting electrical power available.

For day / night luminous intensity adjustment, there are variants of the continuous adjustment of the luminous intensity depending on the applied voltage, or the active switching between operating conditions day and night. Previous solutions with continuous adaptation usually have the disadvantage that the lowering of the light intensity at night is too low. An active switching has the advantage that greater light intensity differences, for example by controlling a different number of LED bulbs / luminous points within a signal point, can be achieved. Likewise, an active switching with presetting of the operating mode could be advantageous for the definition of a generic illuminant interface. Modern LED allow a similar dimming based on rated current of 4: 1, more is required, PWM operation is required.

So far not considered is the observance of a minimum glow limit. It should be avoided that in the event of failure of the "energy-shredder" 20 the LED can already come on with a very low input current at the interface module IM. Ideally, a captive relationship between driving the LED and minimum power consumption can be realized. Otherwise, the monitoring function would have to monitor a minimum power consumption in addition to the luminous flux. Another point to note is that the incandescent lamp is considered to be a strictly resistive resistor with short-term overload resistance and a small time constant with respect to light emission. The brief flash of LED bulbs in the dark state would be intolerable, especially at night and is therefore eliminated with the maintenance of the minimum glow limit.

FIG. 13 shows the lamp characteristic with cold filament. When switching on, there is an ohmic cold resistance of approx. 9 ohms. Within 70 ms, the lamp resistance at day voltage (38V) increases to 68 to 70 ohms.

Claims (14)

Device for implementing a replacement of an incandescent lamp (2) by a more energy-saving illuminant (12) for a light signal in rail-bound traffic, which is included in an interlocking safety monitoring, comprising: a) a number of light sources (12), in particular LED lights, with a power supply interface, wherein the number of light sources for obtaining a luminous intensity analogous to the incandescent lamp requires less electrical power than the incandescent lamp (2) to be replaced; b) an interface-side interface (8) for the purchase of electrical power from the interlocking (4); c) an interface module (IM), which is connected between the interface-side interface (8) and the power supply interface (10), wherein the interface module (IM) c1) comprises a control logic (24) which knows a signal concept and / or time of day dependent characteristic of the incandescent lamp (2) to be replaced and controls the power output to the power supply interface (10) in dependence on the selected signal term and / or the time of day; c2) comprises a voltmeter (30) which measures the voltage applied to the interlocking interface (8) and transmits it to the control logic (24); c3) comprises a power sensor (20), which is controlled by the control logic (24) in dependence on the measured voltage so that the power taken on the inter-processor interface (8) simulates the characteristic curve of the incandescent lamp (2) to be replaced. Device according to claim 1,
characterized in that
the voltmeter (30) operates in TRMS mode. Apparatus according to claim 1 or 2,
characterized in that
the power sensor (20) comprises a power driver (21) in PWM mode. Device according to one of the preceding claims,
characterized in that
the power sensor (20) annihilates a typical inrush current for a cold filament in the incandescent lamp (2) in response to turning the illuminant (12) on the power of the emitter. Device according to claim 4,
characterized in that
the power sensor (20) can drain the inrush current by means of a temporarily parallel resistor, which corresponds to the resistance of the incandescent lamp when the filament is cold, the resistance value preferably decreasing with time. Device according to claim 4,
characterized in that
the power receiver (20) the inrush current in a first temporal portion after the Stellwerkseitigen providing the electrical power to turn on the bulb (12) by means of a temporarily parallel resistor, which corresponds to the resistance of the bulb when the cold filament flows, and in a second subsequent section the parallel resistor replaced by a PMW function to simulate the load characteristic of the bulb. Device according to one of the preceding claims,
characterized in that
the power sensor (20) is connected for a flashing operation of the luminous means (12) with a resistor which is adapted to the state of the hot filament as a result of the flashing operation. Method for implementing a replacement of an incandescent lamp (2) by a more energy-saving illuminant (12) for a light signal in rail-bound traffic, which is included in an interlocking safety monitoring, comprising: a) providing a number of lighting means (12), in particular LED lights, with a power supply interface, wherein the number of lighting means for obtaining a luminous intensity analogous to the incandescent lamp requires less electrical power than the incandescent lamp (2) to be replaced; b) setting up an interface-side interface (8) for the purchase of electrical power from the interlocking (4); c) providing an interface module (IM) which is connected between the interface-side interface (8) and the power supply interface (10), wherein the interface module (IM) c1) comprises a control logic (24) which knows a signal concept and / or time of day dependent characteristic of the incandescent lamp (2) to be replaced and controls the power output to the power supply interface (10) in dependence on the selected signal term and / or the time of day; c2) comprises a voltmeter (30) which measures the voltage applied to the interlocking interface (8) and transmits it to the control logic (24); c3) comprises a power sensor (20), which is controlled by the control logic (24) in dependence on the measured voltage so that the power taken on the inter-processor interface (8) simulates the characteristic curve of the incandescent lamp (2) to be replaced. Method according to claim 8,
characterized in that
the voltmeter (30) operates in TRMS mode. Method according to claim 8 or 9,
characterized in that
the power sensor (20) comprises a power driver (21) in PWM mode. Method according to one of the preceding claims 8 to 10, characterized in that
the power sensor (20) annihilates a typical inrush current for a cold filament in the incandescent lamp (2) in response to turning the illuminant (12) on the power of the emitter. Method according to claim 11,
characterized in that
the power sensor (20) can drain the inrush current by means of a temporarily parallel resistor, which corresponds to the resistance of the incandescent lamp when the filament is cold, the resistance value preferably decreasing with time. Method according to claim 11,
characterized in that
the power receiver (20) the inrush current in a first temporal portion after the Stellwerkseitigen providing the electrical power to turn on the bulb (12) by means of a temporarily parallel resistor, which corresponds to the resistance of the bulb when the cold filament flows, and in a second subsequent section the parallel resistor replaced by a PMW function to simulate the load characteristic of the bulb. Method according to one of the preceding claims 8 to 13, characterized in that
the power sensor (20) is connected for a flashing operation of the luminous means (12) with a resistor which is adapted to the state of the hot filament as a result of the flashing operation.

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