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

Definitions

• the invention relates to a circuit arrangement and an electronic operating device for the ignition and the operation of discharge lamps.
• Electronic Researchgerä ⁇ te for gas discharge lamps are due to their advantages over conventional ballasts such as higher quality of light, better light output and automatic shutdown of the gas discharge lamps at the end of life more and more used.
• gas discharge lamps were especially circuits with a full bridge used to operate the lamp with a kind alternie ⁇ Governing DC for high pressure. This is necessary because most high pressure gas discharge lamps can not operate with higher frequency AC currents due to resonances in the burner vessel.
• a pulse ignition device is usually used, for which a further switch for triggering the ignition pulse is needed. In the case of lamp types which have a comparatively low ignition voltage, resonance ignition methods are also used.
• a half-bridge branch of the full bridge with an ignition choke and a small-capacity ignition capacitor is used for the resonance ignition.
• the second half bridge branch with buck converter choke and buck converter filter capacitor (larger capacity) is used.
• the buck converter stage operates allows the convenient intermittent Be ⁇ drove which zero voltage switching.
• the object of the invention is therefore to provide a circuit ⁇ arrangement and a method for starting and operating a gas discharge lamp, which no longer has the aforementioned disadvantages.
• the invention is based on the realization that for the operation of a step-down half-bridge in continuous mode is not necessarily a great capacity for Fil ⁇ -esterification of the resulting ripple voltage is necessary. It has been shown that at a higher operating frequency of the buck converter, the ripple voltage can be largely compensated by an inductance. The residual ripple of the voltage applied to the gas discharge lamp can no longer have a negative effect, since the damping of the gas discharge lamp at high operating frequency becomes so high that it smoothes the applied residual ripple itself. Thus can be applied to these much higher ripple voltage without it ⁇ the gas discharge lamp to adversely affect the lifetime than. [9] The high step-down frequency has another positive effect.
• the smoothing inductor L2 can have a smaller design due to the high frequency, which saves further costs. Nevertheless, the smoothing inductor L2 by the high switching frequency capable of a large part of the resulting on Resonenazkondensator Cl voltage ripple is to be smoothed, so that at the Gasentla pressure discharge lamp despite the insufficient filtering by capacitor Cl is applied a voltage ripple, which due to its high frequency can be processed well by the gas discharge lamp.
• the capacitor Cl is dimensioned so that it forms a series resonant circuit together with the lamp inductor Ll, via the excitation of the ignition voltage for the gas discharge lamp is generated.
• the half-bridge is operated at a frequency near the resonant frequency to excite the series resonant circuit of Ll and Cl, and to generate a high ignition voltage, which is then applied to the lamp 5 via L2.
• the half-bridge is operated with the usual alternating direct current, wherein a high driving frequency of the transistors is superimposed in order to realize the Tiefsetzereigenschaften.
• FIG. 1 Circuit diagram of the circuit arrangement according to the invention.
• FIG. 2 Signal waveforms of a deep-set half-bridge in non-gap operation according to the prior art.
• FIG. 3 Signal curves of a deep-setting half-bridge according to the invention in intermittent operation.
• FIG. 4 Circuit diagram of the circuit arrangement according to the invention of the second embodiment.
• Fig. 1 shows the circuit diagram of the circuit arrangement according to the invention in the first embodiment.
• the intermediate circuit voltage Uz is applied. It is usually between 380V and 400V.
• the circuit arrangement consists of a symmetrical half-bridge, which contains two serially arranged switches Sl and S2 with the associated coupling capacitors C3 and C4, which are connected to the intermediate circuit voltage.
• a series circuit of a lamp inductor Ll, a smoothing inductor L2 and the gas discharge lamp 5 is connected.
• a resonance capacitor Cl is connected,
• ADJUSTED SHEET (RULE 91) ISA / EP the other end is on circuit ground 1.
• the resonance capacitor Cl forms the series resonant circuit 17 together with the lamp inductor L1.
• the half-bridge In order to ignite the gas discharge lamp 5, the half-bridge is operated at a frequency which is close to the resonance frequency of the series resonant circuit 17. This builds up a high voltage across the capacitor Cl, which thus acts as a firing capacitor.
• the half-bridge is operated at a low frequency, which is in the range of 100Hz - 1000Hz. This low frequency is superimposed on a high chopper frequency, which is in the range of 20OkHz - 50OkHz. This frequency is necessary in order to down-convert the higher intermediate circuit voltage U z to the lower operating voltage of the gas discharge lamp. Due to this superimposed frequency, a high voltage ripple arises on the same due to the small capacitance value of the capacitor C1.
• the capacitance value of the capacitor C1 can be determined from the following formula:
• P L denotes the nominal lamp power.
• Capacitance C N can range from 4nF to about
• the capacitance C N moves between 4nF and 1OnF.
• FIGS. 2 and 3 are considered.
• the waveforms of some important signals are one
• ADJUSTED SHEET (RULE 91) ISA / EP Circuit arrangement according to the prior art shown. As already indicated, this circuit arrangement consists of a half-bridge which is operated in a non-positive manner. As a result, very high switching losses occur here.
• the circuit itself is in principle very similar to the circuit of the present invention. For non-gap operation, a small filter capacitor as used in the present invention is sufficient.
• the voltage applied to the filter capacitor with the comparatively low voltage ripple is represented by the signal 31.
• the signal 34 at the same level represents the voltage at the lamp.
• the already very small voltage ripple is completely compensated by a filter choke and the lamp itself.
• the signal 32 represents the pulse width modulated half-bridge voltage at point 24.
• FIG. 3 shows the same signals in the case of the circuit arrangement according to the invention.
• the half-bridge is operated quasi-resonantly, which makes it possible to switch on the switching transistors with virtually no voltage. Quasi-resonant means in this context that the inductor current is at the boundary between gapless and non-gaping operation.
• the signal 44 clearly shows the large voltage ripple on the capacitor Cl.
• the capacitor C1 is
• ADJUSTED SHEET (RULE 91) ISA / EP fills a double function.
• the capacitor Cl now serves as a filter capacitor.
• the throttle Ll is used during the ignition as resonance throttle and during normal operation as a lamp choke.
• the signal 41 represents the voltage across the lamp. It is still a slight ripple recognizable, but it is not critical by its high frequency for the gas discharge lamp. This shows the difference to the known prior art.
• the voltage ripple is not compensated by a filter capacitance, but by the filter inductance L2.
• the signal 42 again represents the half-bridge medium voltage, and the signal 43, the current through the inductor Ll.
• the capacitances involved during the quasi-resonant transient process consist of the switch capacitances; in the case of MOSFETs these are the drain-source capacitances, the trapezoid capacitances additionally arranged above the switches and the parasitic capacitance of the resonant choke.
• the capacitances involved in the transient are also referred to as effective half-bridge center point capacitance. This midpoint capacity should be as small as possible. For this it is necessary to keep the participating individual capacities small. This can be done by appropriate Drucktransistoren- as well as by a low-capacitance winding structure of the resonance inductor Ll.
• the trapezoidal capacitors should also be dimensioned as small as possible.
• the parameter Ii should be in a range between 0.4 * I N and 0.6 * I N , where I N is the nominal current of the gas discharge lamp.
• the second embodiment instead of the conventional half-bridge arrangement, an arrangement is used in which two buck converters are connected in parallel. This arrangement is also referred to as a change bottom setter.
• the first buck converter is active when the lamp current is positive, whereas the second buck converter is active when the lamp current is negative.
• the buck converters consist of a series circuit of a switching element (S3, S4) and a diode (Dl, D2).
• a buck converter inductor (Ll, LlI) is connected at its first end.
• the second end of the buck converter inductor is connected to a resonant capacitor 19, which consists of at least one of the capacitors.
• ADJUSTED SHEET (RULE 91) ISA / EP Cl and / or CIl and / or C5, connected.

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• Circuit Arrangements For Discharge Lamps (AREA)

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• 2007
  • 2007-04-24 WO PCT/EP2007/053971 patent/WO2008128576A2/fr active Application Filing
  • 2007-04-24 CN CN2007800526782A patent/CN101658067B/zh not_active Expired - Fee Related
  • 2007-04-24 US US12/596,991 patent/US8222828B2/en not_active Expired - Fee Related
  • 2007-04-24 EP EP07728427A patent/EP2140731A2/fr not_active Withdrawn
• 2008
  • 2008-04-18 TW TW097114182A patent/TW200908800A/zh unknown

Non-Patent Citations (1)

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