WO2004045257A1 - Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur - Google Patents

Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur Download PDF

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Publication number
WO2004045257A1
WO2004045257A1 PCT/IB2002/005157 IB0205157W WO2004045257A1 WO 2004045257 A1 WO2004045257 A1 WO 2004045257A1 IB 0205157 W IB0205157 W IB 0205157W WO 2004045257 A1 WO2004045257 A1 WO 2004045257A1
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WO
WIPO (PCT)
Prior art keywords
lamp
current
lamp current
waveform
high frequency
Prior art date
Application number
PCT/IB2002/005157
Other languages
English (en)
Inventor
Simon Richard Greenwood
Stephen Soar
Original Assignee
Simon Richard Greenwood
Stephen Soar
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 Simon Richard Greenwood, Stephen Soar filed Critical Simon Richard Greenwood
Priority to PCT/IB2002/005157 priority Critical patent/WO2004045257A1/fr
Priority to AU2002368347A priority patent/AU2002368347A1/en
Publication of WO2004045257A1 publication Critical patent/WO2004045257A1/fr

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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
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • H05B41/3927—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by pulse width modulation
    • H05B41/3928—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by pulse width modulation for high-pressure lamps, e.g. high-intensity discharge lamps, high-pressure mercury or sodium lamps
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

  • This invention relates to an apparatus and method for improving the colour spectrum of the light emitted from a high intensity discharge (HID) lamp when operating under less than nominal power conditions (i.e. when dimmed).
  • the invention is particularly, though not exclusively, suited to the ballasting of metal halide discharge lamps.
  • Typically such systems can be used for highway lighting, architectural floodlighting, warehouse, retail display and industrial lighting.
  • ballasting for HID lamps is by use of inductors or chokes capable of controlling the lamp current through the impedance they present in series with the mains supply voltage.
  • a high striking voltage typically 4-5 kV, is required to ionize the gas filling the tube and to initiate the arc.
  • HID lamps In prior art systems for ballasting HID lamps, the lamp ballasting means and the lamp striking means are typically discrete circuit elements. Historically, HID lamps have been ballasted by using the impedance of a series connected inductor for controlling the lamp current and a separate starter or igniter module to provide the necessary high voltage to strike the lamp.
  • a conventional power factor controller 2 is formed by transistor TR1, inductor LI, diode Dl and capacitor Cl .
  • Alternating positive and negative output voltage is provided to the lamp by a full bridge arrangement of a lamp bridge 4 comprising four transistors TR3,TR4,TR5,TR6.
  • the transistors are alternately switched on and off in complementary pairs TR3,TR6 and TR4,TR5 at a low frequency, typically 100-200 Hz.
  • an igniter circuit 5 comprising pulse transformer TX1, a Sidac, capacitor C3 and resistor Rl .
  • the capacitor C3 charges through resistor Rl to a voltage at which the Sidac device switches on, discharging the capacitor C3 into the primary winding of the transformer TX1.
  • the voltage applied to the transformer primary is multiplied by the high turns ratio of the transformer and is sufficient to ionize the gas filling the lamp's arc tube, thereby initiating an arc.
  • the igniter Since the voltage is AC, the arc will be extinguished when the lamp current approaches zero and the voltage applied to the tube is subsequently reversed. Therefore the igniter must operate again in the opposite voltage half cycle to re- strike the arc for the flow of current in the opposite direction. This ignition cycle is repeated until the lamp electrodes are sufficiently heated by the arc current for thermionic emission to take place. Then the arc voltage in the tube falls below the threshold voltage of the Sidac and arc current is maintained without operation of the igniter circuit.
  • a further transistor TR2 of a current source 3 controls the flow of current in the output bridge circuit and consequently controls the lamp current.
  • Transistor TR2 is turned on until the current in inductor L2 reaches a preset threshold value, then the transistor TR2 is turned off. Current continues to flow via a diode D2 until the current has decayed to another preset threshold value, then the transistor TR2 is turned on again.
  • this controlled current is further controlled by a lamp power control circuit 6 which takes account of lamp arc voltage and sets the lamp current accordingly so as to maintain the lamp power (watts) at a near constant value over a range of lamp arc voltages.
  • Fig. 3 illustrates schematically a typical lamp current waveform in accordance with the above prior art, with the lamp operating at nominal power.
  • Fig. 4 illustrates a typical lamp current waveform in accordance with the prior art with the lamp operating at a dimmed or reduced power.
  • the invention provides a circuit for improving the light spectrum emitted from a dimmed high intensity discharge lamp by superimposing a high frequency waveform onto a substantially square wave lamp current derived from a high intensity discharge lamp ballast, characterized in that the frequency and mark to space ratio of the high frequency waveform are such that for each half cycle of a resultant waveform, the magnitude of a RMS lamp current is greater than the magnitude of an average lamp current.
  • the invention further provides a method for improving the light spectrum emitted from a dimmed high intensity discharge lamp wherein a high frequency waveform is superimposed on a substantially square wave lamp current derived from a high intensity discharge lamp ballast, characterized in that the frequency and mark to space ratio of the high frequency waveform are such that for each half cycle of a resultant waveform, the magnitude of a RMS lamp current is greater than the magnitude of an average lamp current.
  • the modulation of lamp arc current increases the RMS value of the lamp arc current whilst maintaining an average lamp arc current commensurate with dimmed or reduced power operation.
  • Substantially the average value of light output from a typical metal halide lamp or other high intensity discharge lamp is controlled by the average current whilst, substantially the operating temperature of a typical metal halide lamp or other high intensity discharge lamp arc tube and contents thereof is controlled by the RMS arc current.
  • Figure 1 illustrates a lamp ballast circuit according to the prior art
  • Figure 2 illustrates a lamp ballast block diagram according to the prior art
  • Figure 3 illustrates schematically a typical lamp current waveform in accordance with the prior art with the lamp operating at nominal power (the rise and fall times of the waveform have been exaggerated for clarity);
  • Figure 4 illustrates a typical lamp current waveform in accordance with the prior art with the lamp operating at a dimmed or reduced power (the rise and fall times of the waveform have been exaggerated for clarity);
  • Figure 5 illustrates a lamp ballast block diagram according to a preferred embodiment of the invention.
  • FIG. 6 illustrates a typical lamp current waveform produced by the lamp ballast of
  • Figure 7 illustrates a lamp current waveform produced by an electronic ballast operating at a high frequency with the lamp operating at a dimmed or reduced power.
  • the square wave fundamental operating frequency lamp current waveform is modulated in this case by a higher frequency square wave.
  • the amplitude and mark to space ratio of this modulating waveform it is possible to alter the RMS current content of the overall lamp arc current waveform relative to the average current value of the lamp arc current waveform.
  • the formula for evaluating the values of the average current and the RMS current in the illustrated waveform in Fig. 6 is as follows:
  • II is the current value at the maximum current plateau
  • tl is the time during which the waveform is at the maximum current plateau
  • 12 is the current value at the minimum current plateau
  • t2 is the time during which the waveform is at the minimum current plateau.
  • modulating frequency and wave shape Care must be taken in the choice of modulating frequency and wave shape so as to avoid the possibility of stimulating acoustic arc resonance effects.
  • the choice of frequency, mark to space ratio and modulating frequency waveform may be dictated by the lamp type or other factors such as audible noise caused by the modulating frequency.
  • modulation frequency waveforms other than square wave such as sinusoidal, triangular or other waveforms so as to minimize the problems above whilst maximizing the overall colour change effect in the lamp. Care must also be taken to minimize the damage that may be caused to the lamps electrodes by excessive high peak arc currents.
  • the relationships of II, tl, 12 and t2 varies as a function of specific lamps or by type of lamp.
  • the thermal time constant of the lamp may influence the relationships.
  • Other values of II, 12, tl and t2 than shown in Fig. 6 may be used, such as having tl longer or the same as t2 and/or the difference between II and 12 being greater or lesser.
  • the lamp current square wave operates within 50-200 Hz
  • the higher frequency modulation waveform (coulor control waveform) operates within 500 Hz - 2 kHz
  • the ripple current is about 100 kHz.
  • Other frequencies, frequency ranges and relative frequencies between these three waveforms may be used.
  • Fig. 5 shows the added lamp current modulator 7 for modulating the ratio of the II to 12 higher frequency current and controlling the tl to t2 ratio.
  • a typical ballasting circuit for HID lamps consists of a power factor controller circuit 2 which controls the power factor of the ballast presented to the mains input voltage. This power factor circuit 2 generates a DC voltage controlled bus to which a switch mode current source circuit 3 is connected.
  • the current source circuit 3 controls the lamp current by means of a reference voltage signal (A) which is connected to one input of a comparator.
  • the other input of the comparator is provided with a voltage proportional to lamp current signal (B). When the signal voltage (A) is less than the signal voltage (B), the comparator causes the current source transistor to turn on.
  • the current source transistor is connected to an inductor as per Fig. 1 (prior art).
  • the current in this inductor and therefore the lamp bridge and lamp increases at a rate dependent on lamp voltage, DC bus voltage and the inductance value of the inductor.
  • the comparator causes the current source transistor to turn off.
  • the current in the inductor is then commutated to the diode as shown in Fig 1.
  • the current reduces at a rate dependent on lamp voltage and inductance value until the lamp current proportional voltage signal (B) is below the voltage of the reference voltage signal (A) when the comparator again switches on the current source transistor.
  • the comparator is provided with a fixed hysteresis such that the current is switched on and off between two preset values around the desired current value thus limiting the switching frequency of the current source transistor to a reasonable frequency (approx. 50 - 200kHz).
  • the lamp current modulator 7 modulates the voltage of the reference voltage signal (A) so that the lamp current is similarly modulated in sympathy with the voltage of the reference voltage signal (A).
  • a programmed microprocessor, application specific integrated circuit, transistors, switches, analog devices, digital devices or similar device now known or later developed is so programmed to drive a digital to analogue converter.
  • the digital to analogue converter adds to or subtracts from the voltage of the reference voltage signal (A) to modulate the lamp current with the higher frequency square wave.
  • analog circuits or other devices for adding or subtracting from the voltage reference signal (A) are used.
  • HID lamps such as metal halide lamps
  • HID lamps are operated at high frequency (in the range 20kHz to 2MHz) from electronic ballasts at a reduced (dimmed) power.
  • the frequency, amplitude and mark to space ratio of the lamp current modulation waveform is controlled such that as discussed above in reference to Fig. 6 and shown in Fig. 7 such that the average lamp current is lower than the RMS and peak lamp currents.
  • the temperature of the arc tube and the contents thereof are maintained thereby, keeping the arc tube contents (dose) in a gaseous state and therefore improving the color rendering of the lamp nearer to that which is expected of a lamp operating at nominal power.
  • the high frequency lamp current may be substantially triangular, sinusoidal, square or other in shape.
  • the amplitude modulation of the high frequency lamp current may be effected by modulating the frequency of the waveform or by other means, such as hardware current limiting, altering the lamp series connected impedance or DC bus voltage in response to a signal generated by a software program in a microcontroller or by hardware signal generation.

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  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

L'invention concerne un système permettant de modifier le spectre de couleur ou d'améliorer le rendu de ce spectre: on modifie pour cela les valeurs du rapport entre le courant d'arc de lampe moyen et le courant d'arc de lampe efficace dans une lampe à décharge haute intensité, généralement une lampe à halogène-métal fonctionnant en dessous de la puissance nominale.
PCT/IB2002/005157 2002-11-12 2002-11-12 Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur WO2004045257A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/IB2002/005157 WO2004045257A1 (fr) 2002-11-12 2002-11-12 Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur
AU2002368347A AU2002368347A1 (en) 2002-11-12 2002-11-12 Improved lamp colour control for dimmed high intensity discharge lamps

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2002/005157 WO2004045257A1 (fr) 2002-11-12 2002-11-12 Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur

Publications (1)

Publication Number Publication Date
WO2004045257A1 true WO2004045257A1 (fr) 2004-05-27

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PCT/IB2002/005157 WO2004045257A1 (fr) 2002-11-12 2002-11-12 Commande amelioree de spectre de couleur de lampe pour lampes a decharge haute intensite equipees d'un gradateur

Country Status (2)

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AU (1) AU2002368347A1 (fr)
WO (1) WO2004045257A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1610595A1 (fr) * 2004-06-23 2005-12-28 Sanyo Tecnica Co. Ltd. Lampe à décharge à haute intensité et méthode pour la commander
WO2007004101A1 (fr) * 2005-06-30 2007-01-11 Philips Intellectual Property & Standards Gmbh Procede permettant de commander une lampe a decharge dans un systeme de projection et unite de commande
WO2009099711A1 (fr) * 2008-02-08 2009-08-13 General Electric Company Réglage de couleur d'une lampe à décharge durant une gradation

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3636901A1 (de) * 1986-10-30 1988-05-05 Philips Patentverwaltung Verfahren zum betrieb einer hochdruck-natriumdampfentladungslampe
EP0334356A1 (fr) * 1988-03-25 1989-09-27 Kombinat Veb Narva Lampe de décharge à vapeur métallique stabilisée par les parois
EP0439863A1 (fr) * 1990-01-29 1991-08-07 Koninklijke Philips Electronics N.V. Dispositif de commutation
EP0439864A1 (fr) * 1990-01-29 1991-08-07 Koninklijke Philips Electronics N.V. Dispositif de commutation
EP0504967A1 (fr) * 1991-03-15 1992-09-23 Koninklijke Philips Electronics N.V. Circuit de commutation
US5483126A (en) * 1993-01-19 1996-01-09 Patent-Treuhand-Gesellschaft F. Elektrische Gluehlampen Mbh Method of controlling the color temperature in a sodium high-pressure discharge lamp, and apparatus to carry out the method
WO1999008492A1 (fr) * 1997-08-05 1999-02-18 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Procede pour faire fonctionner une lampe a arc a halogenures metalliques a courant continu, et circuit associe
US6441564B1 (en) * 1999-06-14 2002-08-27 Matsushita Electric Works Research And Development Laboratories Inc High efficacy pulsed, dimmable high pressure cesium lamp

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3636901A1 (de) * 1986-10-30 1988-05-05 Philips Patentverwaltung Verfahren zum betrieb einer hochdruck-natriumdampfentladungslampe
EP0334356A1 (fr) * 1988-03-25 1989-09-27 Kombinat Veb Narva Lampe de décharge à vapeur métallique stabilisée par les parois
EP0439863A1 (fr) * 1990-01-29 1991-08-07 Koninklijke Philips Electronics N.V. Dispositif de commutation
EP0439864A1 (fr) * 1990-01-29 1991-08-07 Koninklijke Philips Electronics N.V. Dispositif de commutation
EP0504967A1 (fr) * 1991-03-15 1992-09-23 Koninklijke Philips Electronics N.V. Circuit de commutation
US5483126A (en) * 1993-01-19 1996-01-09 Patent-Treuhand-Gesellschaft F. Elektrische Gluehlampen Mbh Method of controlling the color temperature in a sodium high-pressure discharge lamp, and apparatus to carry out the method
WO1999008492A1 (fr) * 1997-08-05 1999-02-18 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Procede pour faire fonctionner une lampe a arc a halogenures metalliques a courant continu, et circuit associe
US6441564B1 (en) * 1999-06-14 2002-08-27 Matsushita Electric Works Research And Development Laboratories Inc High efficacy pulsed, dimmable high pressure cesium lamp

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1610595A1 (fr) * 2004-06-23 2005-12-28 Sanyo Tecnica Co. Ltd. Lampe à décharge à haute intensité et méthode pour la commander
WO2007004101A1 (fr) * 2005-06-30 2007-01-11 Philips Intellectual Property & Standards Gmbh Procede permettant de commander une lampe a decharge dans un systeme de projection et unite de commande
WO2009099711A1 (fr) * 2008-02-08 2009-08-13 General Electric Company Réglage de couleur d'une lampe à décharge durant une gradation
US7928669B2 (en) 2008-02-08 2011-04-19 General Electric Company Color control of a discharge lamp during dimming

Also Published As

Publication number Publication date
AU2002368347A1 (en) 2004-06-03

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