JPS589559B2 - fritsukaresugatahodentototosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flickerless discharge lamp lighting device.

A circuit diagram of a conventional flickerless discharge lamp lighting device is shown in FIG.

In the figure, 1 is an AC power supply, 2 and 3 are its secondary voltage V2
1 1 V22 is a leakage transformer that generates sufficient voltage to start the discharge lamps 4 and 5, respectively, and 6 is a phase advancing capacitor.

The leaky transformers 2 and 3 must generate a secondary voltage sufficient to start the discharge lamps 4 and 5, and also raise the voltage V21, which should originally be lowered due to the input power ratio, to the level of the voltage V22. As a result, the ballast as a whole was extremely large, heavy, and expensive.

Therefore, a flickerless discharge lamp lighting device as shown in FIG. 2 was proposed.

That is, in this device, a leaky transformer 7 having a partially saturated characteristic, a phase advance capacitor 8, and a discharge lamp 9 constitute a phase advance lighting circuit, and a leakage transformer 10 and a discharge lamp 11 constitute a phase delay lighting circuit. It consists of

In this case, the voltage V21 is a distorted wave voltage having a voltage peak value that can start the discharge lamp 9, and its effective value can be significantly lower than V21 in FIG. 1, and the withstand voltage of the phase advance capacitor 8 is also reduced It became possible to do so.

Further, the voltage V22 is a voltage that allows steady lighting of the discharge lamp 11 to be maintained, and can be significantly lower than voltage (2) in FIG.

The major structural feature of this device is that the starting capacitor 1
2 is introduced, and the action of this starting capacitor 12 allows the voltage 2 to be reduced to a low value.

To briefly explain the starting operation of the discharge lamp 11, the AC power supply 1
Due to the input of the leakage transformer 7? A current ICS containing many harmonic components flows due to the voltage (V21 V22) in the closed circuit formed by the output winding, the starting capacitor 12, and the output winding of the leakage transformer 10, and a leakage transformer occurs at voltage 2. A voltage drop occurs due to the reactance of the transformer 10, and the current ICS is a phase-advanced current, so the leakage transformer 10
The secondary voltage is modulated and boosted to start the discharge lamp 11.

On the other hand, the discharge lamp 9 is started and steadily lit by the voltage V21, and the discharge lamp 11 also shifts to steady lighting by the voltage V22.
After that, the discharge lamps 9 and 11 are kept lit independently.

In this way, when the device in Figure 2 is compared with the device in Figure 1,
Decrease in voltage V2, ■22, phase advance capacitor? By reducing the pressure resistance of sensor 8, etc., smaller size, lighter weight, and lower cost were achieved.
Furthermore, by selecting the effective value of the voltage V21 to be larger than the effective value of the voltage ■2, it is possible to add the effect of increasing the frizzless effect (tube currents I l1 and ■ l2
(the electrical angle of is close to 90°).

However, when paying attention to the steady lighting of the discharge lamps 9 and 11, the only drawback was that waveform distortion occurred in ■l1 and ■l2 due to the influence of the starting capacitor 12.

This will be explained in detail with reference to FIG.

That is, FIG. 3 shows the relationship between the waveforms of tube currents I and I with reference to voltages V21 and v2.

Now, focus on the tube current ■t2? Then, the tube current ■t1 becomes O(5
), that is, when the impedance of the discharge lamp 9 becomes very high, t2 is near the peak value, that is, the impedance of the discharge lamp 11 is very low.
There is a period when the series impedance of the starting capacitor 12 and the discharge lamp 11 becomes relatively low compared to the series impedance of the Shin-Aigawa capacitor 8 and the discharge lamp 9.

At this time, the tube current IP2 of the discharge lamp 11 is shunted to the leakage transformer 7, the starting capacitor 12, and the circuit of the discharge lamp 11, and the current ■1 is the tube current ■t due to the voltage ■2 at this time.
2, the tube current ■t2 has a current waveform as shown in FIG. 3b.

The same is true for the tube current It1, and the current IPI appears in the circuit of the leakage transformer 10, the starting capacitor 12, and the discharge lamp 9, and the tube current ■t1 becomes as shown in FIG. 3C.

These pulse-like peak currents IPI j IP2 may shorten the life of the discharge lamps 9 and 11, and peaks may also appear in the light output, which may particularly affect precision work. However, in some cases, the current crest factor may fall outside the specified range of various standards.

Therefore, an object of the present invention is to provide a flickerless discharge lamp lighting device that is smaller, lighter, and less expensive, and can improve the discharge lamp current waveform.

FIG. 4 is a circuit diagram of an embodiment of the flickerless discharge lamp lighting device of the present invention, in which the same parts as those in FIG. 2 are given the same reference numerals.

The parts of FIG. 4 that differ from FIG. 2 are the connection points of the leakage transformer 10, the discharge lamp 11, and the starting capacitor 12.

The discharge lamp 9 is started by voltage (2) and shifts to steady lighting.

? Before starting the lamp 11, the power supply winding and the output winding of the leakage transformer 10 are separated by the discharge lamp 11 itself, and the starting capacitor 12 is connected to the output winding of the leakage transformer 10 by voltage (■2+V23). A current ICS with a load of ICS flows.

At this time, the voltage ■21 has a distorted waveform similar to that in the case of FIG. The pressure will be boosted.

The discharge lamp 11 is started by this boosted voltage v2, and thereafter the circuit including the leakage transformer 10 and the discharge lamp 11 shifts to steady lighting.

Regarding boosting of voltage V2, in the case of Fig. 2, voltage FV2
1 v2)? This is due to the flowing current ICS. 5.
l. It was smaller than the current ICS due to the voltage (V21 + V23) in FIG. 4, and therefore the degree of boosting of the voltage (2) was low.

That is, the degree of boosting of the voltage V22 in FIG. 4 is greater than that in FIG. 2.

Also, the leakage in Figure 2. The direction of the fundamental wave advancing phase ICS flowing into the output winding of the transformer 10 is rather in the direction of decreasing V22, and the harmonic components have a large proportion in boosting the voltage 22, whereas in FIG. Since both the fundamental wave and harmonic components of the current CS work favorably in boosting the voltage v2, the starting of the discharge lamp 11 is also superior to that in FIG.

Next, what about the tube currents I tt and I t2 after steady lighting? If you think about it, now, near the peak of ■t,ki0, that is, ■t2, the current I of the discharge lamp 11 due to the voltage V22
/, is in the direction shown in FIG. 4, the current IP2 is shunted in the direction shown in FIG. 4, and the tube current lt2 due to the voltage 2 is
Since the direction is opposite to that of the current t2, the current t2 has a waveform with a somewhat concave near the peak as shown in FIG. 5b.

The degree of this indentation depends on voltage V21 in case (1) in Fig. 2, whereas in case (1) in Fig. 4, voltage V24 = (
V21-VS), the height of the pulsed portion is smaller than in the case of FIG. 2, and there is a desirable direction from the point of view of waveform distortion.

Similarly, the waveform of the tube current I/ can be improved for exactly the same reason.

Note that IPI depends on voltage V23. As mentioned above,
According to the flickerless discharge lamp lighting device of the present invention, the discharge lamp current waveform is improved while satisfying all the advantages of the flickerless discharge lamp lighting device as shown in FIG. 2, which is an improvement over the conventional method. This makes it possible to eliminate shortening of the life of the discharge lamp, adverse effects on precision work etc. due to the presence of pulse-like peaks in light output, and problems with standards regarding current crest factor.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional flickerless discharge lamp lighting device, Fig. 2 is a circuit diagram of a flickerless discharge lamp lighting device which is the basis of this invention, Fig. 3 is its waveform diagram, and Fig. 4 is a circuit diagram of the invention. FIG. 5 is a circuit diagram of an embodiment of the flickerless discharge lamp lighting device, and FIG. 5 is a waveform diagram thereof. 1... AC power supply, 7, 10... Leakage transformer, 8... Phase advancing capacitor, 9, 11...
...discharge lamp, 12...starting capacitor.

Claims (1)

[Claims] 1. Connect one or more sets of discharge lamp lighting circuits to the output side of a first leaky autotransformer with partially saturated characteristics that generates a secondary voltage capable of starting the first discharge lamp, and The second discharge lamp is connected between the power supply winding and the output winding of a second leaky autotransformer that generates a relatively low voltage capable of maintaining lighting of the discharge lamp, and the start end of the power supply winding and the output The ends of the windings are connected to form one or more sets of discharge lamp lighting circuits, each of the discharge lamp lighting circuits formed by the first and second autotransformers has a flicker-free configuration, and the second A flickerless discharge lamp lighting device, wherein a connection point between an output winding of an autotransformer and the second discharge lamp is connected to a terminal end of an output winding of the first autotransformer via a starting capacitor.