JPH0136320Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] This invention relates to a discharge lamp lighting device for lighting discharge lamps such as fluorescent lamps at high frequency, and in particular, a balancer and sequential lighting for lighting multiple discharge lamps in series and parallel. The present invention relates to a discharge lamp lighting device having a sequence impedance of

[Background technology]

As shown in FIG. 3, the conventional discharge lamp lighting device converts a commercial power source 1 into DC using a rectifier bridge 2 and a capacitor 3, supplies it to an inverter device 4, drives the inverter device 4, and then converts the commercial power source 1 into direct current through an output transformer 5. The discharge lamps 9 to 12 are turned on at high frequency. In the figure, 6 indicates discharge lamps 9 and 10 and discharge lamp 1.
7 and 8 are sequence capacitors for sequentially lighting the discharge lamps 9 and 10 and 11 and 12 connected in series, respectively.

In such a configuration, when the commercial power supply 1 is first turned on, the balancer 6 and sequence capacitor 7
Alternatively, the discharge lamp 10 or 12 is slightly discharged via the sequence capacitor 8 and its conductance increases, so that the discharge lamps 9, 10, 11, and 12 connected in series can be lit at once. Now, for example, when the discharge lamps 9 and 10 are lit in this way, if the discharge lamps 11 and 12 are not lit, an autotransformer is formed with the winding N ₂ using the winding N ₁ of the balancer 6 as an excitation inductance. , therefore, the induced voltage of the winding N ₂ and the voltage of the output transformer 5 are added, and the discharge lamp 1
1 and 12, the discharge lamps 11 and 12 also start. After all lights are turned on, magnetic flux acts so that equal currents flow through both windings of the balancer 6, keeping the currents balanced, and when the currents are equal, the magnetic fluxes cancel each other out.

Now, assuming that the discharge lamp 11 to which the sequence capacitor 8 is connected in parallel is pulled out, an equivalent circuit as shown in FIG. 4 can be drawn. Here, L ₀ is the leakage inductance of the output transformer 5, R and R' are the discharge lamps 9, 10, 12
The equivalent resistance C in the lighting state represents the capacitance of the sequence capacitor 8. The impedance 1/ωC of the sequence capacitor 7 is omitted because it is much larger than the equivalent resistance R when the discharge lamp 9 is lit.

In the equivalent circuit of Fig. 4, the secondary winding _N2 side of the balancer 6 becomes a capacitor load, and the balancer 6
It was found that a series resonance effect was caused by the secondary winding inductance of , and the capacitance of the sequence capacitor 8, and a very large resonant voltage E 〓 _C was generated between both ends of the sequence capacitor 8, that is, between the lamp socket of the discharge lamp 11. did. Also,
Large voltages E〓 ₂ and E〓 ₁ are also generated in the windings N ₁ and N ₂ of the balancer 6, and the lamp currents of the discharge lamps 9 and 10 are suppressed. That is, in a multi-lamp series-parallel lighting circuit using the balancer 6, the sequence capacitor 7,
If a discharge lamp with 8 connected in parallel is removed, a very large voltage may be generated between the lamp sockets, and there is a high risk of burnout of the lamp socket or electric shock. In addition, I〓 ₁ is the winding N ₁ of the balancer 6
, I〓 ₂ is the current flowing through the winding N ₂ of balancer 6, E〓 _R , E〓 _R ′ is the lamp voltage of the discharge lamp, E〓 ₀
is the voltage on the power supply side of the leakage inductance L ₀ , and E〓 ₀ ' is the voltage on the load side of the leakage inductance.

[Purpose of invention]

This idea consists of a series circuit of multiple discharge lamps connected to an inverter device via a balancer for parallel lighting, and a sequence impedance for sequential lighting connected in parallel to some of the multiple discharge lamps. An object of the present invention is to provide a discharge lamp lighting device capable of improving safety by reducing the voltage generated between the lamp sockets when a discharge lamp having sequence impedances connected in parallel is removed.

[Disclosure of invention]

The discharge lamp lighting device of this invention connects a series circuit of a plurality of discharge lamps to the output end of an inverter device via a balancer for parallel lighting, and sequentially connects some of the discharge lamps in the series circuit of the plurality of discharge lamps. In a discharge lamp lighting device in which sequence impedances for lighting are connected in parallel, since an inductor is used as the sequence impedance, resonance does not occur even when the discharge lamp in which inductors are connected in parallel is removed.
Therefore, no high voltage is generated between the lamp sockets, and the risk of burnout of the lamp socket or electric shock is extremely low, and safety is high.

Embodiment A first embodiment of this invention will be described based on FIG. This discharge lamp lighting device has saturable reactors 13 and 14 connected in parallel to discharge lamps 9 and 11, respectively, in place of the sequence capacitors 7 and 8 in FIG. 3, and is otherwise the same as that in FIG. be. That is, the commercial power source 1 is converted into DC by the rectifier bridge 2 and the capacitor 3, and is supplied to the inverter device 4 to drive the inverter device 4, and the discharge lamps 9 to 9 are supplied via the output transformer 5 and balancer 6.
The discharge lamps 9 to 12 are illuminated at high frequency by the saturable reactors 13 and 14.
The lights are now lit sequentially.

In such a configuration, when the commercial power supply 1 is first turned on, the discharge lamp 10 is
Alternatively, since the discharge lamp 12 slightly discharges and its conductance increases, the discharge lamps 9, 10, 11, and 12 connected in series can be lit at once. Now, for example, in this way, the discharge lamps 9, 1
0 lights up, if the discharge lamps 11 and 12 are not lit, an autotransformer is formed with the winding N _{2 using the winding N 1 of} the balancer 6 as the excitation inductance, and therefore the induced voltage in the winding N ₂ and the voltage of the output transformer 5 are added to the discharge lamps 11 and 12.
, the discharge lamps 11 and 12 also start. After all lights are turned on, magnetic flux acts so that equal currents flow through both windings of the balancer 6, keeping the currents balanced, and when the currents are equal, the magnetic fluxes cancel each other out.

Furthermore, if the saturable reactors 13 and 14 are used as sequence impedances for sequential lighting,
For example, when the discharge lamp 11 is removed, the equivalent circuit becomes one in which the capacitance C in Fig. 4 is replaced with an inductance, and the winding _N2 side of the balancer 6 from which the discharge lamp 11 is removed becomes an inductive load. , series resonance as shown in Fig. 3 does not occur, and high voltage due to resonance does not occur between both ends of the saturable reactor 14, that is, between the lamp socket of the discharge lamp 11, causing burnout of the lamp socket and electric shock due to the high voltage. Therefore, safety can be improved. Furthermore, even if a voltage is generated in the winding _N2 of the balancer 6 due to current imbalance in the balancer 6, the saturable reactor 14 is saturated, so a high voltage will not be generated across the saturable reactor 14. There are no high voltages between the lamp sockets,
It's safe.

Note that the same operation as described above is performed even when the discharge lamp 13 is removed.

A second embodiment of this invention will be explained based on FIG. In this discharge lamp lighting device, a series circuit of discharge lamps 9 and 10 and a series circuit of discharge lamps 11, 12, and 15 are connected to windings N ₁ and N ₂ of a balancer 6, respectively, and a saturable reactor is connected to the discharge lamp 9. 13 are connected in parallel, and a saturable reactor 14 is connected in parallel to the series circuit of the discharge lamps 11 and 12.Other configurations and effects are the same as in the first embodiment.

Note that the number of discharge lamps connected in series may be four or more, and saturable reactors do not need to be provided in all parallel circuits, but may be provided only in the discharge lamp series circuit connected to one winding of the balancer. .
Furthermore, by combining a plurality of balancers, the number of parallel discharge lamps can be increased to three or more.

[Effect of idea]

The discharge lamp lighting device of this invention connects a series circuit of a plurality of discharge lamps to the output end of an inverter device via a balancer for parallel lighting, and sequentially connects some of the discharge lamps in the series circuit of the plurality of discharge lamps. In a discharge lamp lighting device in which sequence impedances for lighting are connected in parallel, since an inductor is used as the sequence impedance, resonance does not occur even when the discharge lamp in which inductors are connected in parallel is removed.
Therefore, no high voltage is generated between the lamp sockets, and the risk of burnout of the lamp socket or electric shock is extremely low, and safety is high.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a first embodiment of this invention, Fig. 2 is a circuit diagram of a second embodiment of this invention, Fig. 3 is a circuit diagram of a conventional discharge lamp lighting device, and Fig. 4 is a circuit diagram of a conventional discharge lamp lighting device. Third
It is an equivalent circuit diagram when the discharge lamp in the figure is removed. 4...Inverter device, 6...Balancer, 9~
12...discharge lamp, 13,14...saturable reactor (inductor).

Claims (1)

[Claims for Utility Model Registration] (1) A series circuit of a plurality of discharge lamps is connected to the output end of an inverter device via a balancer for parallel lighting, and a discharge lamp of a part of the series circuit of the plurality of discharge lamps is connected to the output end of an inverter device via a balancer for parallel lighting. 1. A discharge lamp lighting device in which a sequence impedance for sequential lighting is connected in parallel to a discharge lamp, characterized in that an inductor is used as the sequence impedance. (2) The discharge lamp lighting device according to claim (1), wherein the inductor is a saturable reactor.