EP1994805A1 - Circuit arrangement and method for operating a high-pressure discharge lamp - Google Patents

Circuit arrangement and method for operating a high-pressure discharge lamp

Info

Publication number
EP1994805A1
EP1994805A1 EP07712190A EP07712190A EP1994805A1 EP 1994805 A1 EP1994805 A1 EP 1994805A1 EP 07712190 A EP07712190 A EP 07712190A EP 07712190 A EP07712190 A EP 07712190A EP 1994805 A1 EP1994805 A1 EP 1994805A1
Authority
EP
European Patent Office
Prior art keywords
pressure discharge
discharge lamp
voltage
circuit arrangement
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP07712190A
Other languages
German (de)
French (fr)
Other versions
EP1994805B1 (en
Inventor
Alois Braun
Joachim MÜHLSCHLEGEL
Walter Limmer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Osram GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram GmbH filed Critical Osram GmbH
Publication of EP1994805A1 publication Critical patent/EP1994805A1/en
Application granted granted Critical
Publication of EP1994805B1 publication Critical patent/EP1994805B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
    • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
    • H05B41/2881—Load circuits; Control thereof
    • H05B41/2882—Load circuits; Control thereof the control resulting from an action on the static converter
    • H05B41/2883—Load circuits; Control thereof the control resulting from an action on the static converter the controlled element being a DC/AC converter in the final stage, e.g. by harmonic mode starting
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
    • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
    • H05B41/292—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2928—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the lamp against abnormal operating conditions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/07—Starting and control circuits for gas discharge lamp using transistors

Definitions

  • the present invention relates to a circuit arrangement for operating a high-pressure discharge lamp comprising a bridge circuit having at least two switches and a control device which is designed to control the at least two switches. It also relates to an operating method for a high-pressure discharge lamp in a circuit arrangement comprising a half-bridge circuit with exactly two switches, a control device which switches the first and the second switch of the half-bridge circuit on and off alternately at a first frequency, and during the off-phase of a switch drives the other switch with a square wave signal of a second frequency, which is greater than the first frequency, and a predetermined duty cycle.
  • the present invention generally relates to the problem of extinguishing high-pressure discharge lamps.
  • high pressure discharge lamps are connected to a full bridge circuit, i. H. on a bridge circuit with four switches.
  • a full bridge circuit i. H. on a bridge circuit with four switches.
  • the object of the present invention is therefore to provide the circuit arrangement mentioned at the outset or the operating method mentioned at the outset. ren educate such that the operation of as many types of high pressure discharge lamps is also possible using a half-bridge circuit.
  • the present invention is based on the finding that a half-bridge circuit is less "stiff" in comparison to a full-bridge circuit, ie has less voltage reserves (insufficient open circuit voltage) DC link voltage Uzw, which is applied to the half-bridge circuit, as well as the time course of the current I L through the lamp and the voltage U L on the lamp
  • the zero line for the voltage U L is marked “4", while the zero line for the current I L is denoted by "3".
  • a control device which alternately the first and the second switches of the half bridge circuit switched at a first frequency and off and during the off phase of the one switch to another switch with a square-wave signal of a second frequency , which is greater than the first frequency, and a predetermined Einschaltdau
  • the first frequency is in the embodiment of Fig. 1 at 160 Hz, while the second frequency is 90 kHz.
  • the duty cycle of the square wave signal of the second frequency is constant and is about 6 ⁇ s.
  • FIG. 1 provides the following result: Because of the real transducer output characteristic, which is flatter in a half-bridge circuit than in a full-bridge circuit, the burning voltage of the high-pressure discharge lamp after commutation increases due to the extremely non-linear load which constitutes a high-pressure discharge lamp.
  • the lamp current I L rises after the commutation only to about half of nominal value and then decreases due to plasma cooling and consequent further increase in the burning voltage to zero.
  • a power controller would be considered, which regulates the power converted in the high-pressure discharge lamp to its desired value.
  • power regulators are inherently slow ( ⁇ approximately 100 ms) and can not counteract the sudden high resistance of the high-pressure discharge lamp, see FIG. 1, ( ⁇ approximately 4 ms) almost fast enough.
  • a measurement of the lamp current I L is possible with reasonable effort in a half-bridge circuit only in one direction with respect to the first frequency. Monitoring in the other direction would therefore be "blind” and could not counteract the increase in the burning voltage taking place during such a cycle.
  • a measurement of the lamp current in both current directions continuously or at a high sampling rate results in an undesirably high outlay, especially if, as in the exemplary embodiment , the first frequency is relatively low.
  • the invention takes a different approach. First, it is based on the knowledge that an increase in the burning voltage must be counteracted by an increase in the lamp current. An increase of the burning voltage can be detected easily with a voltage measuring device. This can be done without much effort for both directions - A -
  • the first frequency is also based on keeping the first frequency essentially constant, but instead increasing the switch-on duration of the signal with which one switch of the half-bridge circuit is activated during the off phase of the other switch, at least for a predefinable period of time. This can cause an increase in the lamp current, which together with the increase in the operating voltage of the lamp leads to a power converted in the lamp, which is sufficient to prevent cooling of the plasma, which would cause the lamp to extinguish.
  • the second frequency is reduced. This offers the advantage that the half-bridge switches then turn on when the current in the lamp inductor is equal to zero. This reduces the switching losses in the half-bridge switches.
  • the second frequency is at least 15 kHz, while the first frequency is at most 500 Hz.
  • the predefinable time duration of the increase of the duty cycle is at least 30 ⁇ s, in particular at least 100 ⁇ s, and at most 3 ms, in particular at most 500 ⁇ s.
  • the voltage measuring device, the reference value device, the comparison device and the Control device dimensioned such that the period between the actual exceeding of the at least one limit value and the control of the two switches of the half-bridge circuit with the increased duty cycle is a maximum of 1 ms, in particular a maximum of 0.3 ms.
  • the at least one threshold may be a constant threshold, but may also be a threshold that depends on the average voltage across the high pressure discharge lamp.
  • the latter realization takes into account an age-related shift in the standard burning voltage and makes it possible to detect a deviation independently of the life of the high-pressure discharge lamp.
  • the average voltage of the high-pressure discharge lamp is preferably updated at equidistant times, for example every 50 to 100 ms.
  • control device is designed to measure the increase of the duty cycle as a function of the measured voltage across the high-pressure discharge lamp and / or the time average of the voltage across the high-pressure discharge lamp and / or from the relevant limit value.
  • the control device can furthermore be designed to ignore an exceeding of the limit value by the voltage measured at the high-pressure discharge lamp after the commutation of the current by the high-pressure discharge lamp for a predefinable period of time, in particular for at least 10 ⁇ s. This will ensure that the lamp voltage is not removed until after the period of ignoring, i. H. is evaluated after the originating from the commutation overshoot the lamp voltage. This overshoot is to be distinguished from the unwanted increase in the burning voltage, which is possible due to its limited time.
  • Preferred embodiments of the circuit arrangement according to the invention are characterized in that after an enlargement of the input switching period for the predetermined period of time, the duty cycle is reduced stepwise or continuously back to the initial value. In this case, several intermediate stages may be provided. By this measure, a undershoot in the lamp current can be reliably avoided.
  • control device may also be designed to increase the duty cycle stepwise or continuously.
  • Figure 2 is a schematic representation of the structure of a circuit arrangement according to the invention.
  • FIG. 3 shows the time profile of, in particular, the lamp voltage U L and the lamp current IL in a circuit arrangement according to the invention according to FIG. 2.
  • FIG. 2 shows a schematic representation of the construction of an exemplary embodiment of a circuit arrangement according to the invention.
  • the so-called intermediate circuit voltage Uzw is applied to the two switches S1, S2 in a half-bridge arrangement.
  • this is approximately 200 to 500 V and is usually generated from the mains voltage via a rectifier and a smoothing capacitor.
  • the half-bridge center HB is connected via a lamp inductor L 0 to a first terminal of the lamp LA.
  • a capacitor Ci is connected, which is designed together with the lamp inductor L 0 for igniting the lamp LA.
  • the current flowing through the lamp is denoted by I L , the voltage drop across the lamp to U L.
  • the other terminal of the lamp LA is connected on the one hand via a coupling capacitor C ⁇ i with the pregnant Vietnamesespan- voltage Uzw, on the other hand via a coupling capacitor C ⁇ 2 with a reference potential, in this case ground.
  • the first lamp terminal is connected via a first voltage divider comprising the resistors R1 and R2, the second terminal of the lamp LA via a second voltage divider comprising the resistors R3 and R4 to the reference potential.
  • the respective taps of the two voltage dividers are connected to a voltage measuring device 10 for measuring the actual value of the voltage U L across the high-pressure discharge lamp LA for determining a voltage which is correlated with the lamp voltage U L.
  • a reference value device 12 provides at least one upper limit value for the voltage U L across the high-pressure discharge lamp LA to a comparison device 14.
  • the comparison device 14 is designed to provide the actual value of the voltage U L over the high-pressure discharge lamp LA, which is supplied by the voltage measuring device 10, with the at least one upper limit value for the Voltage U L across the high pressure discharge lamp LA, which provides the reference value device 12 to compare.
  • the circuit arrangement of Fig. 2 further comprises a control device 16 which is adapted to alternately turn on and off the first switch S1 and the second switch S2 of the bridge circuit at a first frequency, and the other during the off phase of the one switch S1, S2 Switch S2, S1 with a square wave signal of a second frequency, which is greater than the first frequency, and to control a predetermined duty cycle.
  • a control device 16 which is adapted to alternately turn on and off the first switch S1 and the second switch S2 of the bridge circuit at a first frequency, and the other during the off phase of the one switch S1, S2 Switch S2, S1 with a square wave signal of a second frequency, which is greater than the first frequency, and to control a predetermined duty cycle.
  • the comparison device determines that the actual value of the voltage U L across the high-pressure discharge lamp LA, in particular the amount thereof, is above the at least one limit value, it controls the control device 16 in such a way that it supplies the presettable duty cycle of the signal with which the one switch S1, S2 of the half-bridge circuit is driven during the off phase of the other switch S2, S1, at least for a predeterminable period of time increased. This increase in the switch-on time leads to an increase in the current I L through the high-pressure discharge lamp LA.
  • FIG. 3 shows the time course of various variables, although it should be pointed out that the representation of FIG. 3 is increased by a factor of 10 in comparison to the representation of FIG.
  • the zero lines for the lamp voltage U L and the lamp current I L coincide and correspond to the center line of the representation, as shown to the left by the overlap of a 3 and a 4.
  • the lamp voltage U L is increased due to the non-linear characteristic of the high-pressure discharge lamp LA.
  • the lamp current I L remains well below its nominal value, in this case 0.4 A.
  • the lamp is operated with too little power and the plasma begins to cool.
  • the second frequency is reduced by about 50%.
  • the signal provided by the comparison device 14 to the control device 16 is denoted by Us, see also FIG. 2.
  • the signal applied to the respectively active switch S1, S2 by the control device 16 is designated by Usi / Us2.
  • the predefinable time duration of the increase of the switch-on duration .DELTA.t amounts in the present case to 300 .mu.s.
  • the lamp current I L increases significantly to a value that is above the nominal value.
  • the burning voltage U L of the high-pressure discharge lamp decreases as a result of the current increase to normal values.
  • the duty cycle ⁇ t is lowered back to the normal value, so that the lamp is then operated at its nominal current.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

The arrangement has a voltage measuring device (10) measuring an instantaneous value of voltage by a high pressure discharge lamp (LA). A reference value device (12) provides an upper threshold for the voltage. A comparison device (14) compares the value with the threshold. The comparison device is designed such that the value lies below the threshold to control a control device (16) such that a predetermined duty cycle of signals is increased for a preset time period. A switch (S1) of a half bridge circuit is controlled during in-phase of another switch (S2) with the duty cycle. An independent claim is also included for an operating method for a high pressure discharge lamp in a circuit arrangement.

Description

Beschreibung description
Schaltungsanordnung und Verfahren zum Betreiben einer HochdruckentladungslampeCircuit arrangement and method for operating a high-pressure discharge lamp
Technisches GebietTechnical area
Die vorliegende Erfindung betrifft eine Schaltungsanordnung zum Betreiben einer Hochdruckentladungslampe umfassend eine Brückenschaltung mit mindestens zwei Schaltern und eine Steuervorrichtung, die ausgelegt ist die mindestens zwei Schalter anzusteuern. Sie betrifft überdies ein Betriebsver- fahren für eine Hochdruckentladungslampe an einer Schaltungsanordnung umfassend eine Halbbrückenschaltung mit genau zwei Schaltern, eine Steuervorrichtung, die den ersten und den zweiten Schalter der Halbbrückenschaltung abwechselnd mit einer ersten Frequenz ein- und ausschaltet, und während der Aus-Phase des einen Schalters den anderen Schalter mit einem Rechtecksignal einer zweiten Frequenz, die größer ist als die erste Frequenz, und einer vorgebbaren Einschaltdauer ansteuert.The present invention relates to a circuit arrangement for operating a high-pressure discharge lamp comprising a bridge circuit having at least two switches and a control device which is designed to control the at least two switches. It also relates to an operating method for a high-pressure discharge lamp in a circuit arrangement comprising a half-bridge circuit with exactly two switches, a control device which switches the first and the second switch of the half-bridge circuit on and off alternately at a first frequency, and during the off-phase of a switch drives the other switch with a square wave signal of a second frequency, which is greater than the first frequency, and a predetermined duty cycle.
Stand der TechnikState of the art
Die vorliegende Erfindung betrifft generell die Problematik des Verlöschens von Hochdruckentladungslampen. Üblicherweise werden Hochdruckentladungslampen an einer Vollbrückenschaltung, d. h. an einer Brückenschal- tung mit vier Schaltern, betrieben. Im Hinblick auf eine Kostenreduktion ist es erwünscht, Hochdruckentladungslampen an einer Halbbrückenschaltung zu betreiben. Wie sich in der Praxis herausgestellt hat, führt dies jedoch bei manchen Typen von Hochdruckentladungslampen innerhalb kurzer Zeit zum Verlöschen der Hochdruckentladungslampe.The present invention generally relates to the problem of extinguishing high-pressure discharge lamps. Usually, high pressure discharge lamps are connected to a full bridge circuit, i. H. on a bridge circuit with four switches. With a view to cost reduction, it is desirable to operate high pressure discharge lamps on a half-bridge circuit. However, as has been found in practice, this leads in some types of high pressure discharge lamps within a short time to extinguish the high pressure discharge lamp.
Darstellung der ErfindungPresentation of the invention
Die Aufgabe der vorliegenden Erfindung besteht deshalb darin, die eingangs genannte Schaltungsanordnung bzw. das eingangs genannte Betriebsverfah- ren derart weiterzubilden, dass der Betrieb möglichst vieler Typen von Hochdruckentladungslampen auch unter Verwendung einer Halbbrückenschaltung ermöglicht wird.The object of the present invention is therefore to provide the circuit arrangement mentioned at the outset or the operating method mentioned at the outset. ren educate such that the operation of as many types of high pressure discharge lamps is also possible using a half-bridge circuit.
Diese Aufgabe wird gelöst durch eine Schaltungsanordnung mit den Merk- malen von Patentanspruch 1 sowie durch ein Betriebsverfahren mit den Merkmalen von Patentanspruch 14.This object is achieved by a circuit arrangement having the features of patent claim 1 and by an operating method having the features of patent claim 14.
Der vorliegenden Erfindung liegt die Erkenntnis zugrunde, dass eine Halbbrückenschaltung im Vergleich zu einer Vollbrückenschaltung weniger „steif" ist, d. h. weniger Spannungsreserven aufweist (zu geringe Leerlaufspan- nung). Fig. 1 zeigt zur Erläuterung der sich daraus ergebenden Konsequenzen den zeitlichen Verlauf der sogenannten Zwischenkreisspannung Uzw, die an der Halbbrückenschaltung anliegt, sowie den zeitlichen Verlauf des Stroms IL durch die Lampe sowie der Spannung UL an der Lampe. Die Nulllinie für die Spannung UL ist mit „4" gekennzeichnet, während die Nulllinie für den Strom IL mit „3" bezeichnet ist. Dabei wurde eine Steuervorrichtung verwendet, die abwechselnd den ersten und den zweiten Schalter der Halbbrückenschaltung mit einer ersten Frequenz ein- und ausschaltet und während der Aus-Phase des einen Schalters den anderen Schalter mit einem Rechtecksignal einer zweiten Frequenz, die größer ist als die erste Frequenz, und einer vorgebbaren Einschaltdauer ansteuert. Die erste Frequenz liegt im Ausführungsbeispiel von Fig. 1 bei 160 Hz, während die zweite Frequenz bei 90 kHz liegt. Die Einschaltdauer des Rechtecksignals der zweiten Frequenz ist konstant und beträgt ca. 6 μs.The present invention is based on the finding that a half-bridge circuit is less "stiff" in comparison to a full-bridge circuit, ie has less voltage reserves (insufficient open circuit voltage) DC link voltage Uzw, which is applied to the half-bridge circuit, as well as the time course of the current I L through the lamp and the voltage U L on the lamp The zero line for the voltage U L is marked "4", while the zero line for the current I L is denoted by "3". In this case, a control device has been used which alternately the first and the second switches of the half bridge circuit switched at a first frequency and off and during the off phase of the one switch to another switch with a square-wave signal of a second frequency , which is greater than the first frequency, and a predetermined Einschaltdau The first frequency is in the embodiment of Fig. 1 at 160 Hz, while the second frequency is 90 kHz. The duty cycle of the square wave signal of the second frequency is constant and is about 6 μs.
Die Analyse von Fig. 1 liefert folgendes Ergebnis: Aufgrund der realen Wand- lerausgangskennlinie, die bei einer Halbbrückenschaltung flacher ist als bei einer Vollbrückenschaltung, erhöht sich die Brennspannung der Hochdruckentladungslampe nach der Kommutierung aufgrund der äußerst nichtlinearen Last, die eine Hochdruckentladungslampe darstellt. Der Lampenstrom IL steigt nach der Kommutierung nur mehr auf ca. den halben Nenn- wert an und sinkt dann aufgrund von Plasmaauskühlung und dadurch bedingter weiterer Erhöhung der Brennspannung bis auf Null ab.The analysis of FIG. 1 provides the following result: Because of the real transducer output characteristic, which is flatter in a half-bridge circuit than in a full-bridge circuit, the burning voltage of the high-pressure discharge lamp after commutation increases due to the extremely non-linear load which constitutes a high-pressure discharge lamp. The lamp current I L rises after the commutation only to about half of nominal value and then decreases due to plasma cooling and consequent further increase in the burning voltage to zero.
Betriebsintern wurden verschiedene Ansätze geprüft, wie diesem Problem begegnet werden kann:In-house, various approaches have been tested to address this problem:
Zunächst käme ein Leistungsregler in Betracht, der die in der Hochdruckentladungslampe umgesetzte Leistung auf ihren Sollwert regelt. Derartige Leistungsregler sind jedoch prinzipbedingt langsam (τ ungefähr 100 ms) und können dem plötzlichen Hochohmigwerden der Hochdruckentladungslampe, siehe Fig. 1 , (τ ungefähr 4 ms) nicht annähernd schnell genug entgegenwir- ken.Initially, a power controller would be considered, which regulates the power converted in the high-pressure discharge lamp to its desired value. However, such power regulators are inherently slow (τ approximately 100 ms) and can not counteract the sudden high resistance of the high-pressure discharge lamp, see FIG. 1, (τ approximately 4 ms) almost fast enough.
Eine Regelung der Lampenspannung UL würde auf ein Konstanthalten der Spannung hinauslaufen. D. h. einer Erhöhung der Brennspannung würde entgegengewirkt werden, indem die Brennspannung in der Amplitude reduziert wird. Dies würde insbesondere zu einer Reduktion des Lampenstroms führen und dadurch ein Verlöschen der Lampe beschleunigen statt verhindern.Regulation of the lamp voltage U L would result in keeping the voltage constant. Ie. An increase in the burning voltage would be counteracted by the burning voltage is reduced in amplitude. This would in particular lead to a reduction of the lamp current and thereby accelerate a lamp extinction instead of preventing.
Eine Messung des Lampenstroms IL ist mit vertretbarem Aufwand bei einer Halbbrückenschaltung nur in einer Richtung mit Bezug auf die erste Frequenz möglich. In die andere Richtung wäre die Überwachung daher „blind" und könnte der während eines solchen Zyklus stattfindenden Erhöhung der Brennspannung nicht entgegenwirken. Eine Messung des Lampenstroms in beiden Stromrichtungen ständig oder mit hoher Abtastrate resultiert in einem unerwünscht hohen Aufwand vor allem wenn, wie im Ausführungsbeispiel, die erste Frequenz verhältnismäßig niedrig liegt.A measurement of the lamp current I L is possible with reasonable effort in a half-bridge circuit only in one direction with respect to the first frequency. Monitoring in the other direction would therefore be "blind" and could not counteract the increase in the burning voltage taking place during such a cycle. A measurement of the lamp current in both current directions continuously or at a high sampling rate results in an undesirably high outlay, especially if, as in the exemplary embodiment , the first frequency is relatively low.
Die Erfindung geht einen anderen Weg: Zunächst basiert sie auf der Erkenntnis, dass einer Erhöhung der Brennspannung mit einer Erhöhung des Lampenstroms begegnet werden muss. Eine Erhöhung der Brennspannung kann auf einfache Weise mit einer Spannungsmessvorrichtung festgestellt werden. Diese lässt sich ohne größeren Aufwand für beide Richtungen der - A -The invention takes a different approach. First, it is based on the knowledge that an increase in the burning voltage must be counteracted by an increase in the lamp current. An increase of the burning voltage can be detected easily with a voltage measuring device. This can be done without much effort for both directions - A -
ersten Frequenz realisieren. Sie basiert weiterhin darauf, die erste Frequenz im Wesentlichen konstant zu lassen, dafür die Einschaltdauer des Signals, mit dem der eine Schalter der Halbbrückenschaltung während der AusPhase des anderen Schalters angesteuert wird, zumindest für eine vorgeb- bare Zeitdauer zu vergrößern. Dadurch lässt sich eine Vergrößerung des Lampenstroms herbeiführen, die zusammen mit der Vergrößerung der Brennspannung der Lampe zu einer in der Lampe umgesetzten Leistung führt, die ausreichend ist, um eine Abkühlung des Plasmas, was ein Verlöschen der Lampe zur Folge hätte, zu verhindern.realize the first frequency. It is also based on keeping the first frequency essentially constant, but instead increasing the switch-on duration of the signal with which one switch of the half-bridge circuit is activated during the off phase of the other switch, at least for a predefinable period of time. This can cause an increase in the lamp current, which together with the increase in the operating voltage of the lamp leads to a power converted in the lamp, which is sufficient to prevent cooling of the plasma, which would cause the lamp to extinguish.
Das Erstaunliche an der erfindungsgemäßen Lösung besteht darin, dass eigentlich eine Vergrößerung der Einschaltdauer der zweiten Frequenz zu einer weiteren Vergrößerung der Brennspannung der Lampe führen müsste. In der Praxis ist dies jedoch in überraschender Weise aufgrund der Nicht- Linearität der Hochdruckentladungslampe nicht der Fall. Vielmehr führt eine Vergrößerung der Einschaltdauer zu einem Ansteigen des Lampenstroms, damit zu einer Erhitzung des Plasmas und damit zu einem Absinken der Brennspannung.The astonishing thing about the solution according to the invention is that an increase in the duty cycle of the second frequency would actually lead to a further increase in the operating voltage of the lamp. In practice, however, this is surprisingly not the case due to the non-linearity of the high pressure discharge lamp. Rather, an increase in the duty cycle leads to an increase in the lamp current, thus to a heating of the plasma and thus to a decrease in the burning voltage.
Bei einer bevorzugten Ausführungsform wird neben der Vergrößerung der Einschaltdauer die zweite Frequenz verkleinert. Dies bietet den Vorteil, dass die Halbbrückenschalter dann einschalten, wenn der Strom in der Lampendrossel gleich Null ist. Dadurch reduzieren sich die Schaltverluste in den Halbbrückenschaltern.In a preferred embodiment, in addition to increasing the duty cycle, the second frequency is reduced. This offers the advantage that the half-bridge switches then turn on when the current in the lamp inductor is equal to zero. This reduces the switching losses in the half-bridge switches.
In bevorzugten Ausführungsformen beträgt die zweite Frequenz mindestens 15 kHz, während die erste Frequenz maximal 500 Hz beträgt.In preferred embodiments, the second frequency is at least 15 kHz, while the first frequency is at most 500 Hz.
Bevorzugt beträgt die vorgebbare Zeitdauer der Vergrößerung der Einschaltdauer mindestens 30 μs, insbesondere mindestens 100 μs, und höchstens 3 ms, insbesondere höchstens 500 μs.Preferably, the predefinable time duration of the increase of the duty cycle is at least 30 μs, in particular at least 100 μs, and at most 3 ms, in particular at most 500 μs.
Bei einer besonders bevorzugten Weiterbildung ist die Spannungsmessvorrichtung, die Referenzwertvorrichtung, die Vergleichsvorrichtung und die Steuervorrichtung derart bemessen, dass der Zeitraum zwischen dem tatsächlichen Überschreiten des mindestens einen Grenzwerts und des An- steuerns der beiden Schalter der Halbbrückenschaltung mit der erhöhten Einschaltdauer maximal 1 ms, insbesondere maximal 0,3 ms, beträgt.In a particularly preferred development, the voltage measuring device, the reference value device, the comparison device and the Control device dimensioned such that the period between the actual exceeding of the at least one limit value and the control of the two switches of the half-bridge circuit with the increased duty cycle is a maximum of 1 ms, in particular a maximum of 0.3 ms.
Der mindestens eine Grenzwert kann ein konstanter Grenzwert sein, kann jedoch auch ein Grenzwert sein, der von der gemittelten Spannung über der Hochdruckentladungslampe abhängig ist. Die letztgenannte Realisierung trägt einer altersbedingten Verschiebung der Norm-Brennspannung Rechnung und ermöglicht das Erkennen einer Abweichung unabhängig von der Lebensdauer der Hochdruckentladungslampe. Bevorzugt wird die gemittelte Spannung der Hochdruckentladungslampe zu äquidistanten Zeitpunkten aktualisiert, beispielsweise alle 50 bis 100 ms.The at least one threshold may be a constant threshold, but may also be a threshold that depends on the average voltage across the high pressure discharge lamp. The latter realization takes into account an age-related shift in the standard burning voltage and makes it possible to detect a deviation independently of the life of the high-pressure discharge lamp. The average voltage of the high-pressure discharge lamp is preferably updated at equidistant times, for example every 50 to 100 ms.
Besonders bevorzugt ist die Steuervorrichtung ausgelegt, die Vergrößerung der Einschaltdauer zu bemessen in Abhängigkeit der gemessenen Spannung über der Hochdruckentladungslampe und/oder des zeitlichen Mittelwerts der Spannung über der Hochdruckentladungslampe und/oder von dem maßgeblichen Grenzwert.Particularly preferably, the control device is designed to measure the increase of the duty cycle as a function of the measured voltage across the high-pressure discharge lamp and / or the time average of the voltage across the high-pressure discharge lamp and / or from the relevant limit value.
Die Steuervorrichtung kann ferner dazu ausgelegt sein, eine Überschreitung des Grenzwerts durch die an der Hochdruckentladungslampe gemessene Spannung nach der Kommutierung des Stroms durch die Hochdruckentladungslampe für eine vorgebbare Zeitdauer, insbesondere für mindestens 10 μs, zu ignorieren. Dadurch wird sichergestellt, dass die Lampenspannung erst nach dem Zeitraum der Ignorierung, d. h. nach dem durch die Kommutierung herrührenden Überschwinger der Lampenspannung, ausgewertet wird. Dieser Überschwinger ist zu unterscheiden von dem unerwünschten Anwachsen der Brennspannung, was aufgrund seiner zeitlichen Begrenztheit ermöglicht wird.The control device can furthermore be designed to ignore an exceeding of the limit value by the voltage measured at the high-pressure discharge lamp after the commutation of the current by the high-pressure discharge lamp for a predefinable period of time, in particular for at least 10 μs. This will ensure that the lamp voltage is not removed until after the period of ignoring, i. H. is evaluated after the originating from the commutation overshoot the lamp voltage. This overshoot is to be distinguished from the unwanted increase in the burning voltage, which is possible due to its limited time.
Bevorzugte Ausführungsformen der erfindungsgemäßen Schaltungsanordnung zeichnen sich dadurch aus, dass nach einer Vergrößerung der Ein- schaltdauer für die vorgebbare Zeitdauer die Einschaltdauer stufenförmig oder kontinuierlich wieder auf den Ausgangswert verringert wird. Dabei können mehrere Zwischenstufen vorgesehen sein. Durch diese Maßnahme lässt sich ein Unterschwinger im Lampenstrom zuverlässig vermeiden.Preferred embodiments of the circuit arrangement according to the invention are characterized in that after an enlargement of the input switching period for the predetermined period of time, the duty cycle is reduced stepwise or continuously back to the initial value. In this case, several intermediate stages may be provided. By this measure, a undershoot in the lamp current can be reliably avoided.
Im Gegenzug kann die Steuervorrichtung auch ausgelegt sein, die Einschaltdauer stufenförmig oder kontinuierlich zu erhöhen.In return, the control device may also be designed to increase the duty cycle stepwise or continuously.
Weitere vorteilhafte Ausführungsformen ergeben sich aus den Unteransprüchen.Further advantageous embodiments will become apparent from the dependent claims.
Die im Zusammenhang mit der erfindungsgemäßen Schaltungsanordnung erwähnten bevorzugten Ausführungsformen und deren Vorteile gelten, soweit anwendbar, entsprechend für das erfindungsgemäße Betriebsverfahren für eine Hochdruckentladungslampe.The preferred embodiments mentioned in connection with the circuit arrangement according to the invention and their advantages apply, if applicable, correspondingly to the operating method according to the invention for a high-pressure discharge lamp.
Kurze Beschreibu ng der Zeich nu ng(en)Brief description of the drawing (s)
Im Nachfolgenden wird nunmehr ein Ausführungsbeispiel einer erfindungsgemäßen Schaltungsanordnung unter Bezugnahme auf die beigefügten Zeichnungen näher beschrieben. Es zeigen:In the following, an embodiment of a circuit arrangement according to the invention will now be described in more detail with reference to the accompanying drawings. Show it:
Fig. 1 den zeitlichen Verlauf insbesondere der Lampenspannung UL einer Hochdruckentladungslampe und des Lampenstroms IL ohne erfindungsgemäße Maßnahmen;1 shows the time course in particular of the lamp voltage UL of a high-pressure discharge lamp and of the lamp current IL without measures according to the invention;
Fig. 2 in schematischer Darstellung den Aufbau einer erfindungsgemäßen Schaltungsanordnung; undFigure 2 is a schematic representation of the structure of a circuit arrangement according to the invention. and
Fig. 3 den zeitlichen Verlauf insbesondere der Lampenspannung UL und des Lampenstroms IL bei einer erfindungsgemäßen Schaltungsanordnung nach Fig. 2. Bevorzugte Ausführung der Erfindung3 shows the time profile of, in particular, the lamp voltage U L and the lamp current IL in a circuit arrangement according to the invention according to FIG. 2. Preferred embodiment of the invention
Die mit Bezug auf Fig. 1 eingeführten Größen und deren Bezugszeichen werden, soweit gleiche und ähnliche Größen betroffen sind, in den Figuren 2 und 3 weiterverwendet.The variables introduced with reference to FIG. 1 and their reference numerals will continue to be used in FIGS. 2 and 3, insofar as identical and similar quantities are concerned.
Fig. 2 zeigt in schematischer Darstellung den Aufbau eines Ausführungsbei- spiels einer erfindungsgemäßen Schaltungsanordnung. Dabei liegt an den zwei Schaltern S1 , S2 in Halbbrückenanordnung die so genannte Zwischen- kreisspannung Uzw an. Diese beträgt je nach Ausführungsform ca. 200 bis 500 V und wird üblicherweise aus der Netzspannung über einen Gleichrichter und einen Glättungskondensator erzeugt. Der Halbbrückenmittelpunkt HB ist über eine Lampendrossel L0 mit einem ersten Anschluss der Lampe LA verbunden. Mit diesem Anschluss ist überdies ein Kondensator Ci verbunden, der zusammen mit der Lampendrossel L0 zur Zündung der Lampe LA ausgelegt ist. Der durch die Lampe fließende Strom ist mit IL bezeichnet, die an der Lampe abfallende Spannung mit UL. Der andere Anschluss der Lampe LA ist einerseits über einen Koppelkondensator Cκi mit der Zwischenkreisspan- nung Uzw verbunden, andererseits über einen Koppelkondensator Cκ2 mit einem Bezugspotential, vorliegend Masse. Der erste Lampenanschluss ist über einen ersten Spannungsteiler umfassend die Widerstände R1 und R2, der zweite Anschluss der Lampe LA über einen zweiten Spannungsteiler um- fassend die Widerstände R3 und R4 mit dem Bezugspotential verbunden. Die jeweiligen Abgriffe der beiden Spannungsteiler sind zur Ermittlung einer Spannung, die mit der Lampenspannung UL korreliert ist, mit einer Spannungsmessvorrichtung 10 zum Messen des Istwerts der Spannung UL über der Hochdruckentladungslampe LA verbunden. Eine Referenzwertvorrich- tung 12 stellt mindestens einen oberen Grenzwert für die Spannung UL über der Hochdruckentladungslampe LA an eine Vergleichsvorrichtung 14 bereit. Die Vergleichsvorrichtung 14 ist ausgelegt, den Istwert der Spannung UL Ü- ber der Hochdruckentladungslampe LA, der von der Spannungsmessvorrichtung 10 geliefert wird, mit dem mindestens einen oberen Grenzwert für die Spannung UL über der Hochdruckentladungslampe LA, den die Referenzwertvorrichtung 12 bereitstellt, zu vergleichen.FIG. 2 shows a schematic representation of the construction of an exemplary embodiment of a circuit arrangement according to the invention. In this case, the so-called intermediate circuit voltage Uzw is applied to the two switches S1, S2 in a half-bridge arrangement. Depending on the embodiment, this is approximately 200 to 500 V and is usually generated from the mains voltage via a rectifier and a smoothing capacitor. The half-bridge center HB is connected via a lamp inductor L 0 to a first terminal of the lamp LA. With this connection, moreover, a capacitor Ci is connected, which is designed together with the lamp inductor L 0 for igniting the lamp LA. The current flowing through the lamp is denoted by I L , the voltage drop across the lamp to U L. The other terminal of the lamp LA is connected on the one hand via a coupling capacitor Cκi with the Zwischenkreisspan- voltage Uzw, on the other hand via a coupling capacitor Cκ 2 with a reference potential, in this case ground. The first lamp terminal is connected via a first voltage divider comprising the resistors R1 and R2, the second terminal of the lamp LA via a second voltage divider comprising the resistors R3 and R4 to the reference potential. The respective taps of the two voltage dividers are connected to a voltage measuring device 10 for measuring the actual value of the voltage U L across the high-pressure discharge lamp LA for determining a voltage which is correlated with the lamp voltage U L. A reference value device 12 provides at least one upper limit value for the voltage U L across the high-pressure discharge lamp LA to a comparison device 14. The comparison device 14 is designed to provide the actual value of the voltage U L over the high-pressure discharge lamp LA, which is supplied by the voltage measuring device 10, with the at least one upper limit value for the Voltage U L across the high pressure discharge lamp LA, which provides the reference value device 12 to compare.
Die Schaltungsanordnung von Fig. 2 umfasst weiterhin eine Steuervorrichtung 16, die ausgelegt ist, abwechselnd den ersten Schalter S1 und den zweiten Schalter S2 der Brückenschaltung mit einer ersten Frequenz ein- und auszuschalten und während der Aus-Phase des einen Schalters S1 , S2 den anderen Schalter S2, S1 mit einem Rechtecksignal einer zweiten Frequenz, die größer ist als die erste Frequenz, und einer vorgebbaren Einschaltdauer anzusteuern. Stellt nun die Vergleichsvorrichtung fest, dass der Istwert der Spannung UL über der Hochdruckentladungslampe LA, insbesondere deren Betrag, über dem mindestens einen Grenzwert liegt, steuert sie die Steuervorrichtung 16 derart an, dass diese die vorgebbare Einschaltdauer des Signals, mit dem der eine Schalter S1 , S2 der Halbbrückenschaltung während der Aus-Phase des anderen Schalters S2, S1 angesteuert wird, zumindest für eine vorgebbare Zeitdauer vergrößert. Diese Vergrößerung der Einschaltdauer führt zu einer Vergrößerung des Stroms IL durch die Hochdruckentladungslampe LA.The circuit arrangement of Fig. 2 further comprises a control device 16 which is adapted to alternately turn on and off the first switch S1 and the second switch S2 of the bridge circuit at a first frequency, and the other during the off phase of the one switch S1, S2 Switch S2, S1 with a square wave signal of a second frequency, which is greater than the first frequency, and to control a predetermined duty cycle. If the comparison device now determines that the actual value of the voltage U L across the high-pressure discharge lamp LA, in particular the amount thereof, is above the at least one limit value, it controls the control device 16 in such a way that it supplies the presettable duty cycle of the signal with which the one switch S1, S2 of the half-bridge circuit is driven during the off phase of the other switch S2, S1, at least for a predeterminable period of time increased. This increase in the switch-on time leads to an increase in the current I L through the high-pressure discharge lamp LA.
Fig. 3 zeigt den zeitlichen Verlauf diverser Größen, wobei jedoch darauf hinzuweisen ist, dass im Vergleich zu der Darstellung von Fig. 1 die Darstellung von Fig. 3 um den Faktor 10 vergrößert ist. Die Nulllinien für die Lampenspannung UL und den Lampenstrom IL fallen aufeinander und entsprechen der Mittellinie der Darstellung, wie links durch die Überlappung einer 3 und einer 4 zu erkennen. Nach der Kommutierung, d. h. nach dem Zeitpunkt ti ist die Lampenspannung UL aufgrund der nicht-linearen Kennlinie der Hoch- druckentladungslampe LA erhöht. Dadurch bleibt der Lampenstrom IL deutlich unter seinem Nennwert, vorliegend 0,4 A, zurück. Dadurch wird die Lampe mit zu wenig Leistung betrieben und das Plasma beginnt auszukühlen. Die Vergleichsvorrichtung 14, siehe Fig. 2, erkennt ein Überschreiten des Grenzwerts für die Lampenspannung UL und erhöht daraufhin die Einschalt- dauer Δt des Signals, mit dem der eine Schalter der Halbbrückenschaltung während der Aus-Phase des anderen Schalters angesteuert wird zum Zeitpunkt t2. Gleichzeitig wird die zweite Frequenz um etwa 50 % reduziert. Das von der Vergleichsvorrichtung 14 an die Steuervorrichtung 16 bereitgestellte Signal ist mit Us bezeichnet, siehe auch Fig. 2. Das an den jeweils aktiven Schalter S1 , S2 von der Steuervorrichtung 16 angelegte Signal ist mit Usi/Us2 bezeichnet. Die vorgebbare Zeitdauer der Vergrößerung der Einschaltdauer Δt beträgt vorliegend 300 μs. Als Folge der Vergrößerung der Einschaltdauer Δt erhöht sich der Lampenstrom IL deutlich auf einen Wert, der über dem Nennwert liegt. Die Brennspannung UL der Hochdruckentla- dungslampe verringert sich infolge der Stromerhöhung auf normale Werte. Nach dem Ablauf der 300 μs wird die Einschaltdauer Δt wieder auf den normalen Wert abgesenkt, so dass die Lampe anschließend mit ihrem Nennstrom weiterbetrieben wird. FIG. 3 shows the time course of various variables, although it should be pointed out that the representation of FIG. 3 is increased by a factor of 10 in comparison to the representation of FIG. The zero lines for the lamp voltage U L and the lamp current I L coincide and correspond to the center line of the representation, as shown to the left by the overlap of a 3 and a 4. After the commutation, ie after the time ti, the lamp voltage U L is increased due to the non-linear characteristic of the high-pressure discharge lamp LA. As a result, the lamp current I L remains well below its nominal value, in this case 0.4 A. As a result, the lamp is operated with too little power and the plasma begins to cool. The comparison device 14, see FIG. 2, detects an exceeding of the limit value for the lamp voltage U L and then increases the switch-on duration Δt of the signal with which the one switch of the half-bridge circuit is driven during the off phase of the other switch at the time t 2 . At the same time, the second frequency is reduced by about 50%. The signal provided by the comparison device 14 to the control device 16 is denoted by Us, see also FIG. 2. The signal applied to the respectively active switch S1, S2 by the control device 16 is designated by Usi / Us2. The predefinable time duration of the increase of the switch-on duration .DELTA.t amounts in the present case to 300 .mu.s. As a result of the increase in the duty cycle .DELTA.t, the lamp current I L increases significantly to a value that is above the nominal value. The burning voltage U L of the high-pressure discharge lamp decreases as a result of the current increase to normal values. After the expiry of the 300 μs, the duty cycle Δt is lowered back to the normal value, so that the lamp is then operated at its nominal current.

Claims

Ansprüche claims
1. Schaltungsanordnung zum Betreiben einer Hochdruckentladungslampe umfassend:1. Circuit arrangement for operating a high-pressure discharge lamp, comprising:
- eine Brückenschaltung mit mindestens zwei Schaltern (S1 , S2),a bridge circuit having at least two switches (S1, S2),
- eine Steuervorrichtung (16), die ausgelegt ist die mindestens zwei Schalter (S1 , S2) anzusteuern; dadurch gekennzeichnet, dass die Brückenschaltung als Halbbrückenschaltung mit genau zwei Schaltern (S1 , S2) ausgebildet ist, wobei die Steuervorrichtung (16) ausgelegt ist, abwechselnd den ersten Schalter (S1 ) und den zweiten Schal- ter (S2) der Brückenschaltung mit einer ersten Frequenz ein- und auszuschalten, und während der Aus-Phase des einen Schalters (S1 , S2) den anderen Schalter (S2, S1 ) mit einem Rechtecksignal einer zweiten Frequenz, die größer ist als die erste Frequenz, und einer vorgebbaren Einschaltdauer anzusteuern, wobei die Schaltungsanordnung weiterhin umfasst:- A control device (16) which is designed to control the at least two switches (S1, S2); characterized in that the bridge circuit as a half-bridge circuit with exactly two switches (S1, S2) is formed, wherein the control device (16) is designed, alternately the first switch (S1) and the second switch (S2) of the bridge circuit with a first Frequency on and off, and during the off phase of the one switch (S1, S2) to control the other switch (S2, S1) with a square wave signal of a second frequency, which is greater than the first frequency, and a predetermined duty cycle, wherein the circuit arrangement further comprises:
- eine Spannungsmessvorrichtung (10) zum Messen eines Istwerts der Spannung über der Hochdruckentladungslampe (LA);- A voltage measuring device (10) for measuring an actual value of the voltage across the high pressure discharge lamp (LA);
- eine Referenzwertvorrichtung (12), die mindestens einen oberen Grenzwert für die Spannung (UL) über der Hochdruckentladungslampe (LA) bereitstellt;- a reference value device (12) providing at least an upper limit voltage (UL) across the high pressure discharge lamp (LA);
- eine Vergleichsvorrichtung (14) zum Vergleichen des Istwerts der Spannung (UL) über der Hochdruckentladungslampe mit dem mindestens einen Grenzwert; wobei die Vergleichsvorrichtung (14) ausgelegt ist in dem Fall, in dem der Istwert der Spannung (UL) über der Hochdruckentladungslampe (LA) über dem mindestens einen Grenzwert liegt, die Steuervorrichtung (16) derart anzusteuern, dass diese die vorgebbare Einschaltdauer des Signals, mit dem der eine Schalter (S1 , S2) der Halbbrückenschaltung während dera comparison device (14) for comparing the actual value of the voltage (UL) across the high-pressure discharge lamp with the at least one limit value; wherein the comparison device (14) is designed, in the case where the actual value of the voltage (UL) across the high-pressure discharge lamp (LA) is above the at least one limit value, to control the control device (16) in such a way that it determines the presettable duty cycle of the signal, with which a switch (S1, S2) of the half-bridge circuit during the
Aus-Phase des anderen Schalters (S2, S1 ) angesteuert wird, zumindest für eine vorgebbare Zeitdauer vergrößert. Off phase of the other switch (S2, S1) is driven, at least increased for a predetermined period of time.
2. Schaltungsanordnung nach Anspruch 1 , dadurch gekennzeichnet, dass die Schaltungsanordnung derart ausgelegt ist, dass die Vergrößerung der Einschaltdauer (Δt) zu einer Vergrößerung des Stroms (IL) durch die Hochdruckentladungslampe (LA) führt.2. A circuit arrangement according to claim 1, characterized in that the circuit arrangement is designed such that the increase in the duty cycle (.DELTA.t) leads to an increase in the current (IL) through the high-pressure discharge lamp (LA).
3. Schaltungsanordnung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass neben der Vergrößerung der Einschaltdauer (Δt) die zweite Frequenz verkleinert wird.3. Circuit arrangement according to claim 1 or 2, characterized in that in addition to the increase in the duty cycle (.DELTA.t), the second frequency is reduced.
4. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die zweite Frequenz mindestens 15 kHz beträgt.4. Circuit arrangement according to one of the preceding claims, characterized in that the second frequency is at least 15 kHz.
5. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die erste Frequenz maximal 500 Hz beträgt.5. Circuit arrangement according to one of the preceding claims, characterized in that the first frequency is at most 500 Hz.
6. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die vorgebbare Zeitdauer der Vergrößerung der Einschaltdauer (Δt) mindestens 30 μs, insbesondere mindestens 100 μs, und höchstens 3 ms, insbesondere höchstens 500 μs, beträgt.6. Circuit arrangement according to one of the preceding claims, characterized in that the predefinable period of increase in the duty cycle (At) at least 30 microseconds, in particular at least 100 microseconds, and at most 3 ms, in particular at most 500 microseconds.
7. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Spannungsmessvorrichtung (10), die Referenzwertvorrichtung (12), die Vergleichsvorrichtung (14) und die Steuervorrichtung (16) derart bemessen sind, dass der Zeitraum zwischen dem tatsächlichen Überschreiten des mindestens einen Grenzwerts und des Ansteuerns der bei- den Schalter (S1 , S2) der Halbbrückenschaltung mit der erhöhten Einschaltdauer (Δt) maximal 1 ms, insbesondere maximal 0,3 ms, beträgt.7. Circuit arrangement according to one of the preceding claims, characterized in that the voltage measuring device (10), the reference value device (12), the comparison device (14) and the control device (16) are dimensioned such that the period between the actual exceeding of the at least one Limit value and the triggering of the the switch (S1, S2) of the half-bridge circuit with the increased duty cycle (At) is a maximum of 1 ms, in particular a maximum of 0.3 ms.
8. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der mindestens eine Grenzwert ein konstanter Grenzwert ist.8. Circuit arrangement according to one of the preceding claims, characterized in that the at least one limit value is a constant limit value.
9. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der mindestens eine Grenzwert ein Grenzwert ist, der von der gemit- telten Spannung über der Hochdruckentladungslampe (LA) abhängig ist.9. Circuit arrangement according to one of the preceding claims, characterized in that the at least one limit value is a limit value which is dependent on the averaged voltage across the high-pressure discharge lamp (LA).
10. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Steuervorrichtung (16) ausgelegt ist, die Vergrößerung der Einschaltdauer (Δt) zu bemessen in Abhängigkeit der gemessenen Spannung (UL) über der Hochdruckentladungslampe (LA) und/oder des zeitli- chen Mittelwerts der Spannung (UL) über der Hochdruckentladungslampe und/oder vom dem maßgeblichen Grenzwert.10. Circuit arrangement according to one of the preceding claims, characterized in that the control device (16) is designed to measure the increase in the duty cycle (.DELTA.t) as a function of the measured voltage (UL) on the high-pressure discharge lamp (LA) and / or the temporal average voltage (UL) across the high pressure discharge lamp and / or from the relevant limit.
11. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Steuervorrichtung (16) ausgelegt ist, eine Überschreitung des Grenzwerts durch die an der Hochdruckentladungslampe (LA) gemessene Spannung (UL) nach der Kommutierung des Stroms (IL) durch die Hochdruckentladungslampe (LA) für eine vorgebbare Zeitdauer, insbesondere für mindestens 10 μs, zu ignorieren.11. Circuit arrangement according to one of the preceding claims, characterized in that the control device (16) is designed to exceed the limit value by the at the high pressure discharge lamp (LA) measured voltage (UL) after the commutation of the current (IL) by the high-pressure discharge lamp ( LA) for a predeterminable period of time, in particular for at least 10 μs.
12. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Steuervorrichtung (16) ausgelegt ist, nach einer Vergrößerung der Einschaltdauer (Δt) für die vorgebbare Zeitdauer, die Einschaltdauer (Δt) stufenförmig oder kontinuierlich auf den Ausgangswert zu verringern.12. Circuit arrangement according to one of the preceding claims, characterized in that the control device (16) is designed, after an increase in the switch-on duration (Δt) for the predeterminable period of time, to reduce the switch-on duration (Δt) in steps or continuously to the initial value.
13. Schaltungsanordnung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Steuervorrichtung (16) ausgelegt ist, die Einschaltdauer (Δt) stufenförmig oder kontinuierlich zu erhöhen.13. Circuit arrangement according to one of the preceding claims, characterized in that the control device (16) is designed to increase the duty cycle (.DELTA.t) stepwise or continuously.
14. Betriebsverfahren für eine Hochdruckentladungslampe (LA) an einer Schaltungsanordnung umfassend eine Halbbrückenschaltung mit genau zwei Schaltern (S1 , S2), eine Steuervorrichtung (16), die den ersten (S1 ) und den zweiten Schalter (S2) der Halbbrückenschaltung abwechselnd mit einer ersten Frequenz ein- und ausschaltet, und während der AusPhase des einen Schalters (S1 , S2) den anderen Schalter (S2, S1 ) mit einem Rechtecksignal einer zweiten Frequenz, die größer ist als die erste Frequenz, und einer vorgebbaren Einschaltdauer (Δt) ansteuert, gekennzeichnet durch folgende Schritte: a) Messen eines Istwerts der Spannung (UL) über der Hochdruckentladungslampe (LA); b) Vergleichen des Istwerts der Spannung (UL) über der Hochdruckentla- dungslampe (LA) mit mindestens einem oberen Grenzwert für die14. Operating method for a high-pressure discharge lamp (LA) on a circuit arrangement comprising a half-bridge circuit having exactly two switches (S1, S2), a control device (16) alternating the first (S1) and the second switch (S2) of the half-bridge circuit with a first one Frequency turns on and off, and during the AusPhase the one switch (S1, S2), the other switch (S2, S1) with a square wave signal of a second frequency, which is greater than the first frequency, and a predetermined duty cycle (At) drives, characterized by the steps of: a) measuring an actual value of the voltage (UL) across the high pressure discharge lamp (LA); b) comparing the actual value of the voltage (UL) across the high-pressure discharge lamp (LA) with at least one upper limit value for the
Spannung (UL) über der Hochdruckentladungslampe; c) in dem Fall, in dem der Istwert der Spannung (UL) über der Hochdruckentladungslampe (LA) über dem mindestens einen Grenzwert liegt: Vergrößern der Einschaltdauer (Δt) des Signals, mit dem die beidenVoltage (UL) across the high pressure discharge lamp; c) in the case where the actual value of the voltage (U L ) across the high pressure discharge lamp (LA) is above the at least one limit: increasing the duty cycle (Δt) of the signal with which the two
Schalter (S1 , S2) der Halbbrückenschaltung angesteuert werden, zumindest für eine vorgebbare Zeitdauer. Switch (S1, S2) of the half-bridge circuit are driven, at least for a predetermined period of time.
EP07712190A 2006-02-20 2007-02-08 Circuit arrangement and method for operating a high-pressure discharge lamp Not-in-force EP1994805B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006007754A DE102006007754A1 (en) 2006-02-20 2006-02-20 High pressure discharge lamp operating circuit arrangement, has comparison device designed so that instantaneous value lies below upper threshold such that preset duty cycle of signals is increased for preset time period
PCT/EP2007/051230 WO2007096253A1 (en) 2006-02-20 2007-02-08 Circuit arrangement and method for operating a high-pressure discharge lamp

Publications (2)

Publication Number Publication Date
EP1994805A1 true EP1994805A1 (en) 2008-11-26
EP1994805B1 EP1994805B1 (en) 2009-12-30

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Application Number Title Priority Date Filing Date
EP07712190A Not-in-force EP1994805B1 (en) 2006-02-20 2007-02-08 Circuit arrangement and method for operating a high-pressure discharge lamp

Country Status (7)

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US (1) US8089220B2 (en)
EP (1) EP1994805B1 (en)
CN (1) CN101385399B (en)
AT (1) ATE454027T1 (en)
CA (1) CA2642576A1 (en)
DE (2) DE102006007754A1 (en)
WO (1) WO2007096253A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010039430A1 (en) * 2010-08-18 2012-02-23 Osram Ag Electronic ballast and method for operating at least one discharge lamp
EP2498584B1 (en) 2011-03-07 2013-09-25 Vossloh-Schwabe Deutschland GmbH Ballast for high pressure gas discharge lamps

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03138894A (en) * 1989-10-23 1991-06-13 Nissan Motor Co Ltd Lighting device for discharge lamp
DE69807118T2 (en) * 1997-07-24 2003-05-08 Noontek Ltd Ballast for a gas lamp
DE19917180A1 (en) * 1998-04-18 1999-10-21 Manfred Diez Procedure for running mercury vapor discharge radiator lamp
US6437515B1 (en) * 2000-01-18 2002-08-20 Matsushita Electric Works, Ltd. Discharge lamp lighting device of high startability with high pulse voltage

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2007096253A1 *

Also Published As

Publication number Publication date
CA2642576A1 (en) 2007-08-30
WO2007096253A1 (en) 2007-08-30
DE102006007754A1 (en) 2007-08-23
CN101385399B (en) 2013-03-13
EP1994805B1 (en) 2009-12-30
CN101385399A (en) 2009-03-11
US20090295302A1 (en) 2009-12-03
US8089220B2 (en) 2012-01-03
ATE454027T1 (en) 2010-01-15
DE502007002487D1 (en) 2010-02-11

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