EP0642296A2 - Process for detecting a faulty fluorescent lamp operated by high-frequency - Google Patents

Process for detecting a faulty fluorescent lamp operated by high-frequency Download PDF

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Publication number
EP0642296A2
EP0642296A2 EP94250220A EP94250220A EP0642296A2 EP 0642296 A2 EP0642296 A2 EP 0642296A2 EP 94250220 A EP94250220 A EP 94250220A EP 94250220 A EP94250220 A EP 94250220A EP 0642296 A2 EP0642296 A2 EP 0642296A2
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EP
European Patent Office
Prior art keywords
tube
voltage
frequency
current
fluorescent
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.)
Withdrawn
Application number
EP94250220A
Other languages
German (de)
French (fr)
Other versions
EP0642296A3 (en
Inventor
Dr. Jürgen Dietrich
Detlef Dahms
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.)
SMI SYSTEM MICROELECTRONIC INNOVATION GmbH
Original Assignee
SMI SYSTEM MICROELECTRONIC INNOVATION GmbH
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Filing date
Publication date
Priority claimed from DE4330942A external-priority patent/DE4330942C2/en
Application filed by SMI SYSTEM MICROELECTRONIC INNOVATION GmbH filed Critical SMI SYSTEM MICROELECTRONIC INNOVATION GmbH
Publication of EP0642296A2 publication Critical patent/EP0642296A2/en
Publication of EP0642296A3 publication Critical patent/EP0642296A3/en
Withdrawn legal-status Critical Current

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    • 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
    • H05B41/282—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
    • H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2851—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2855—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions
    • 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
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/20—Responsive to malfunctions or to light source life; for protection
    • H05B47/25—Circuit arrangements for protecting against overcurrent

Definitions

  • the present invention relates to a method for monitoring the lamp current of fluorescent tubes when actuated at higher frequencies.
  • fluorescent tubes are increasingly operated with electronic ballasts which provide a high-frequency operating current.
  • the physical cause of the increased luminous efficiency is, among other things, that with increasing operating frequency the ionization state in the fluorescent tube does not have to be rebuilt after each zero crossing of the lamp current, as is the case when operating at the mains frequency.
  • the operating voltage of a fluorescent tube has voltage peaks during 50 Hz operation, which show that the tube must be ignited again after each zero crossing. These re-ignition peaks are absent when operating at higher frequencies.
  • the tube burns with the mostly sinusoidal operating voltage.
  • fluorescent lamps ignite unreliably at the end of their service life and sometimes shine stochastically. This so-called flickering is perceived as annoying, so that the corresponding tube has to be exchanged or switched off.
  • An improvement is also not achieved by the ballast for fluorescent tubes disclosed in DE-OS 4039161.
  • the invention is based on the object of realizing a method which makes it possible to monitor a fluorescent tube to the extent that it does not reach the state of a light output which is perceived as restless or flickering when it is aged.
  • short-term current peaks of the lamp current detected via a sensing resistor are used, which occur in each half-wave of the HF-shaped supply current. These current peaks indicate the declining ionization state with used fluorescent tubes. Under normal operating conditions, they only occur when the fluorescent tubes are completely used up and no longer ignite in a conventional circuit with mains frequency operation.
  • a used tube has a not exactly sinusoidal operating voltage curve even in high-frequency operation.
  • clear criteria for this condition at the end of the tube's life can be determined.
  • an excessive lamp current can be recognized as a further operating state which is harmful to the tube.
  • This type of error detection according to the invention enables a distinction to be made between random disturbance variables, higher lamp current caused by start-up and faulty pulse-laden lamp current, as occurs in the case of used fluorescent tubes. This method ensures that a one-time or temporarily caused by the start of a fluorescent tube error signal is negated.
  • the error signal 1 consists of current peaks that repeat at the operating frequency and, when the switching threshold 2 is exceeded, cause the comparator 3 to switch.

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  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

The present invention relates to a method for monitoring the lamp current of fluorescent tubes during operation at higher frequencies. It is known that the burning voltage (operating voltage, running voltage, maintaining voltage) of a fluorescent tube, during operation at 50 Hz, has voltage peaks which show that the tube must be restarted after each zero crossing. These restarting peaks are missing during operation at higher frequencies. In this case, the tube operates with the mostly sinusoidal burning voltage. It is furthermore known that fluorescent lamps have an unreliable starting behaviour at the end of their life and glow partly stochastically (randomly). This so-called flicker is regarded as disturbing, with the result that the corresponding tube must be replaced or switched off. With the invention, those states of the tube which inevitably lead to this flicker are recognised and the tube can be switched off automatically before this disturbing effect begins. Even during high-frequency (radio-frequency) operation, a used tube has a burning voltage curve which is not precisely sinusoidal. By detecting the associated burning current, unambiguous criteria can be determined for this state at the end of the life of the tube. In addition, too high a lamp current can be detected (recognised) as a further operating state which is damaging for the tube. <IMAGE>

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Überwachung des Lampenstroms von Leuchtstoffröhren bei Ansteuerung mit höheren Frequenzen.The present invention relates to a method for monitoring the lamp current of fluorescent tubes when actuated at higher frequencies.

Leuchtstoffröhren werden wegen der höheren Lichtausbeute und dem größeren Wirkungsgrad des gesamten zum Betrieb notwendigen Systems zunehmend mit elektronischen Vorschaltgeräten betrieben, die einen hochfrequenten Betriebsstrom bereitstellen.
Die physikalische Ursache für die erhöhte Lichtausbeute liegt unter anderem darin, daß mit zunehmender Betriebsfrequenz der Ionisationszustand in der Leuchtstoffröhre nicht nach jedem Nulldurchgang des Lampenstroms wieder aufgebaut werden muß, wie dies beim Betrieb mit Netzfrequenz der Fall ist.
Bekannt ist, daß die Brennspannung einer Leuchtstoffröhre beim 50 Hz-Betrieb Spannungsspitzen besitzt, die aufzeigen, daß die Röhre nach jedem Nulldurchgang wieder gezündet werden muß. Diese Wiederzündspitzen fehlen beim Betrieb mit höheren Frequenzen.
Die Röhre brennt hierbei mit der meist sinusförmigen Brennspannung.
Weiterhin ist bekannt, daß Leuchtstofflampen am Ende ihrer Lebensdauer unzuverlässig zünden und teilweise stochastisch leuchten. Dieses sogenannte Flackern wird als störend empfunden, so daß die entsprechende Röhre getauscht oder abgeschaltet werden muß.
Eine Verbesserung wird auch nicht durch das in der DE-OS 4039161 bekanntgemachte Vorschaltgerät für Leuchtstoffröhren erreicht.Because of the higher luminous efficiency and the greater efficiency of the entire system required for operation, fluorescent tubes are increasingly operated with electronic ballasts which provide a high-frequency operating current.
The physical cause of the increased luminous efficiency is, among other things, that with increasing operating frequency the ionization state in the fluorescent tube does not have to be rebuilt after each zero crossing of the lamp current, as is the case when operating at the mains frequency.
It is known that the operating voltage of a fluorescent tube has voltage peaks during 50 Hz operation, which show that the tube must be ignited again after each zero crossing. These re-ignition peaks are absent when operating at higher frequencies.
The tube burns with the mostly sinusoidal operating voltage.
Furthermore, it is known that fluorescent lamps ignite unreliably at the end of their service life and sometimes shine stochastically. This so-called flickering is perceived as annoying, so that the corresponding tube has to be exchanged or switched off.
An improvement is also not achieved by the ballast for fluorescent tubes disclosed in DE-OS 4039161.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zu realisieren, das es ermöglicht, eine Leuchtstoffröhre dahingehend zu überwachen, daß sie bei Alterung nicht den Zustand einer als unruhig oder flackernd empfundenen Lichtabgabe erreicht.
Als Kriterium hierfür werden kurzzeitige Stromspitzen des über einen Fühlwiderstand detektierten Lampenstroms benutzt, die in jeder Halbwelle des HF-förmigen Versorgungsstroms auftreten.
Diese Stromspitzen deuten auf den nachlassenden Ionisierungszustand bei verbrauchten Leuchtstoffröhren hin.
Sie treten unter normalen Betriebsbedingungen nur bei völlig verbrauchten Leuchtstoffröhren auf, die in einer herkömmlichen Schaltung mit Netzfrequenzbetrieb schon nicht mehr zünden.The invention is based on the object of realizing a method which makes it possible to monitor a fluorescent tube to the extent that it does not reach the state of a light output which is perceived as restless or flickering when it is aged.
As a criterion for this, short-term current peaks of the lamp current detected via a sensing resistor are used, which occur in each half-wave of the HF-shaped supply current.
These current peaks indicate the declining ionization state with used fluorescent tubes.
Under normal operating conditions, they only occur when the fluorescent tubes are completely used up and no longer ignite in a conventional circuit with mains frequency operation.

Erfindungsgemäß wird diese Aufgabe durch die im Patentanspruch 1 aufgeführten Merkmale gelöst.
Vorteilhafte Ausgestaltungen sind in den Patentansprüchen 2 bis 6 angegeben.According to the invention, this object is achieved by the features listed in claim 1.
Advantageous embodiments are given in claims 2 to 6.

Mit der erfindungsgemäßen Lösung werden die Zustände der Röhre, die zwangsläufig zu diesem Flackern führen, erkannt und die Röhre kann automatisch abgeschaltet werden bevor dieser störende Effekt einsetzt.
Eine verbrauchte Röhre weist auch im hochfrequenten Betrieb einen nicht exakt sinusförmigen Brennspannungsverlauf auf.
Durch Detektierung des zugehörigen Brennstromes lassen sich eindeutige Kriterien für diesen Zustand am Lebensende der Röhre ermitteln.
Zusätzlich kann als weiterer für die Röhre schädlicher Betriebszustand ein zu großer Lampenstrom erkannt werden.
Diese erfindundsgemäße Art der Fehlererfassung ermöglicht die Unterscheidung zwischen zufälligen Störgrößen, anlaufbedingtem höheren Lampenstrom und fehlerhaft impulsbehaftetem Lampenstrom, wie er bei verbrauchten Leuchtstoffröhren auftritt.
Dieses Verfahren stellt sicher, daß ein einmaliges bzw. durch den Startvorgang einer Leuchtstoffröhre zeitweilig bedingtes Fehlersignal negiert wird.With the solution according to the invention, the conditions of the tube which inevitably lead to this flickering are recognized and the tube can be switched off automatically before this disruptive effect sets in.
A used tube has a not exactly sinusoidal operating voltage curve even in high-frequency operation.
By detecting the associated combustion current, clear criteria for this condition at the end of the tube's life can be determined.
In addition, an excessive lamp current can be recognized as a further operating state which is harmful to the tube.
This type of error detection according to the invention enables a distinction to be made between random disturbance variables, higher lamp current caused by start-up and faulty pulse-laden lamp current, as occurs in the case of used fluorescent tubes.
This method ensures that a one-time or temporarily caused by the start of a fluorescent tube error signal is negated.

Die Einzelheiten der Ausführungsform ergeben sich aus der folgenden Beschreibung und aus der Zeichnung, auf die Bezug genommen wird.
Das Verfahren zur Erkennung einer defekten Leuchtstoffröhre bei hochfrequenter Ansteuerung wird am nachfolgenden Ausführungsbeispiel mit zugehörigem Blockschaltbild erläutert.
Das Fehlersignal 1 besteht aus Stromspitzen, die sich mit der Betriebsfrequenz wiederholen und beim Überschreiten der Schaltschwelle 2 den Komperator 3 zum Umschalten bringen.The details of the embodiment result from the following description and from the drawing, to which reference is made.
The method for detecting a defective fluorescent tube with high-frequency control is explained in the following exemplary embodiment with the associated block diagram.
The error signal 1 consists of current peaks that repeat at the operating frequency and, when the switching threshold 2 is exceeded, cause the comparator 3 to switch.

Diese Umschaltsignale werden zyklisch im Zähler 4 gezählt und beim Erreichen eines bestimmten vorgegebenen Zählerstandes wird das erste Register 5 gesetzt.
Mit einem erstmaligen Setzen des ersten Registers 5 wird ausgehend von der Zeitbasis 6 eine Zeitverzögerung 7 gestartet.
Liegt nach Ablauf dieser Verzögerung wiederum ein über ein Fehlersignal erneut gesetztes erstes Register 5 vor, wird ein zweites Register 8 gesetzt, über dessen Auswertung auf das Fehlersignal reagiert werden kann.These changeover signals are counted cyclically in the counter 4 and when a certain predetermined counter reading is reached, the first register 5 is set.
When the first register 5 is set for the first time, a time delay 7 is started based on the time base 6.
If, after this delay has elapsed, a first register 5 is again set via an error signal, a second register 8 is set, via the evaluation of which it is possible to react to the error signal.

Claims (6)

Verfahren zum Erkennen einer defekten Leuchtstoffröhre bei höherfrequenter Ansteuerung sowie verbotener Betriebsbedingungen von Leuchtstoffröhren im Betrieb mit höherfrequenter Ansteuerung, dadurch gekennzeichnet, daß im Ereignisfall auftretende Stromspitzen ab einer bestimmten Amplitude als Fehlersignal in den Ansteuerelementen von einer Auswerteschaltung zeitbezogen erfaßt und gespeichert werden.Method for recognizing a defective fluorescent tube with higher-frequency control and forbidden operating conditions of fluorescent tubes in operation with higher-frequency control, characterized in that in the event of an event current peaks above a certain amplitude are detected and stored as a fault signal in the control elements by an evaluation circuit. Verfahren nach Anspruch 1, dadurch gekenzeichnet, daß ein Komparator (3) zur Erfassung der Stromspitzen (1) ab einer durch die Schaltschwelle (2) vorgegebenen Größe verwendet wird.Method according to Claim 1, characterized in that a comparator (3) is used to detect the current peaks (1) from a size predetermined by the switching threshold (2). Verfahren nach Anspruch 1 und 2, dadurch gekennzeichnet, daß als Auswerteschaltung ein Zähler (4) verwendet wird, der von einer Zeitbasis (6) gesteuert wird.Method according to Claims 1 and 2, characterized in that a counter (4) is used as the evaluation circuit and is controlled by a time base (6). Verfahren nach Anspruch 1 bis 3, dadurch gekennzeichnet, daß in einem definierten Zeitfenster die Stromspitzen (1) gezählt werden und bei Überschreiten einer definierten Anzahl ein erstes Register (5) gesetzt und die Information gespeichert wird.Method according to Claims 1 to 3, characterized in that the current peaks (1) are counted in a defined time window and when a defined number is exceeded a first register (5) is set and the information is stored. Verfahren nach Anspruch 1 und 2, dadurch gekennzeichnet, daß auch bei statisch anliegendem Fehlersignal (1) eine Speicherung des Fehlers analog Punkt 4 erfolgt.Method according to claims 1 and 2, characterized in that the error is stored analogously to point 4 even with a static error signal (1). Verfahren nach Anspruch 4 und 5, dadurch gekennzeichnet, daß bei gesetztem ersten Register (5) nach einer bestimmten definierten Verzögerungszeit (7) eine von einer Zeitbasis (6) bewirkte Wiederholung der Stromspitzenerfassung erfolgt und beim erneuten Überschreiten der definierten Anzahl von Stromspitzen (1) eine bleibende Registrierung im zweiten Register (8) zur weiteren Verarbeitung erfolgt.Method according to Claims 4 and 5, characterized in that when the first register (5) is set, after a certain defined delay time (7) the current peak detection is repeated by a time base (6) and when the defined number of current peaks (1) is exceeded again. permanent registration in the second register (8) for further processing is carried out.
EP94250220A 1993-09-08 1994-09-07 Process for detecting a faulty fluorescent lamp operated by high-frequency. Withdrawn EP0642296A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4330942A DE4330942C2 (en) 1993-09-08 1993-09-08 Method for detecting a defective fluorescent lamp when operating with a higher frequency voltage
DE4330942 1993-09-08

Publications (2)

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EP0642296A2 true EP0642296A2 (en) 1995-03-08
EP0642296A3 EP0642296A3 (en) 1995-07-26

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EP94250220A Withdrawn EP0642296A3 (en) 1993-09-08 1994-09-07 Process for detecting a faulty fluorescent lamp operated by high-frequency.

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0794691A2 (en) * 1996-03-06 1997-09-10 Denso Corporation Device for accurately detecting end of usage lifetime of a discharge lamp
FR2789839A1 (en) * 1999-02-15 2000-08-18 Matsushita Electric Works Ltd Ballast for a discharge lamp used in motor vehicle headlamps
DE19983865B4 (en) * 1999-11-02 2007-01-04 Mitsubishi Denki K.K. Electric ballast for a discharge lamp
US9995364B2 (en) 2013-02-11 2018-06-12 Siemens Aktiengesellschaft Device for mechanically adjusting vibration behavior of a machine element

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1982001276A1 (en) * 1980-10-07 1982-04-15 Grubbs C Solid state ballast with high frequency inverter fault protection
WO1987007995A1 (en) * 1986-06-18 1987-12-30 Innovative Controls, Inc. A high intensity discharge lamp self-adjusting ballast system with current limiters and a current feed-back loop
US5023516A (en) * 1988-05-10 1991-06-11 Matsushita Electric Industrial Co., Ltd. Discharge lamp operation apparatus
EP0576991A2 (en) * 1992-06-30 1994-01-05 Sanyo Electric Co., Ltd. Control apparatus of fluorescent lamp
GB2269279A (en) * 1992-08-01 1994-02-02 Coolite Ltd Fluorescent Tube Starting and Operating Circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1982001276A1 (en) * 1980-10-07 1982-04-15 Grubbs C Solid state ballast with high frequency inverter fault protection
WO1987007995A1 (en) * 1986-06-18 1987-12-30 Innovative Controls, Inc. A high intensity discharge lamp self-adjusting ballast system with current limiters and a current feed-back loop
US5023516A (en) * 1988-05-10 1991-06-11 Matsushita Electric Industrial Co., Ltd. Discharge lamp operation apparatus
EP0576991A2 (en) * 1992-06-30 1994-01-05 Sanyo Electric Co., Ltd. Control apparatus of fluorescent lamp
GB2269279A (en) * 1992-08-01 1994-02-02 Coolite Ltd Fluorescent Tube Starting and Operating Circuit

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0794691A2 (en) * 1996-03-06 1997-09-10 Denso Corporation Device for accurately detecting end of usage lifetime of a discharge lamp
EP0794691A3 (en) * 1996-03-06 1998-06-03 Denso Corporation Device for accurately detecting end of usage lifetime of a discharge lamp
US5880563A (en) * 1996-03-06 1999-03-09 Denso Corporation Device for accurately detecting end of usage lifetime of a discharge lamp
FR2789839A1 (en) * 1999-02-15 2000-08-18 Matsushita Electric Works Ltd Ballast for a discharge lamp used in motor vehicle headlamps
DE19983865B4 (en) * 1999-11-02 2007-01-04 Mitsubishi Denki K.K. Electric ballast for a discharge lamp
US9995364B2 (en) 2013-02-11 2018-06-12 Siemens Aktiengesellschaft Device for mechanically adjusting vibration behavior of a machine element

Also Published As

Publication number Publication date
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