JPS6256638B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a HID lamp (saturated vapor pressure discharge lamp)
This relates to a discharge lamp lighting circuit that turns on a discharge lamp. FIG. 1 shows a conventional circuit in which an inductance L and a lamp L are connected in series to a commercial power supply.
If a quick down occurs, a lamp with a slightly higher lamp voltage will turn off.
HID lamps require a long time of 5 to 10 minutes to restart, which is very inconvenient. In addition, in order to prevent the lamp l from going out due to the quick down of the power supply voltage as mentioned above, it is possible to use a leakage transformer type circuit configuration and keep the no-load secondary voltage high, but in this case, the volt-ampere There was a problem that became very large and caused a significant increase in costs. The present invention has been provided in view of the above-mentioned points, and provides a discharge lamp lighting circuit which prevents the lamp from going out due to a quick down of the power supply voltage, and further reduces the cost by keeping the volt-ampere of the circuit small. The purpose is to An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 2 shows a circuit according to an embodiment of the present invention, in which a series closed circuit of inductance L ₁ , inductance L ₂ and lamp l is connected to a 200V commercial power supply, and a series closed circuit of inductance L ₂ and lamp l is connected to a 200V commercial power supply. This is a so-called slow-phase lighting circuit in which a capacitor C is connected in parallel to the circuit. Thus, the circuit of the embodiment in FIG. 2 has the effect of preventing the lamp l from going out when the power supply voltage is quickly down. Compared to the case where the magnetic flux density of the second inductance L ₂ shown in Figure b is large (Bm = 1.35 Wb/m ² ), the case where the magnetic flux density of the inductance L ₂ shown in Figure b is small (Bm = 0.8 Wb/m ² ) At first,
When the lamp voltage is high, the effect of preventing the circuit from turning off is not as great as that of the conventional circuit shown in Figure 1 (c), and the lamp voltage becomes high at the end of the lamp life. There is a risk that the product may sometimes disappear. This is because the circuit of the embodiment shown in FIG. 2 has a circuit configuration in which the constant current characteristic is stronger, so the lamp with the higher lamp voltage in the conventional circuit of FIG. When used in a circuit, the lamp voltage increases substantially further, resulting in a burnout. Figure 3 shows the experimental results when a 360W high-pressure sodium lamp was used as the lamp l, the power supply voltage quick-down time was all 1 second, and the power supply quick-down rate when the lamp l went out in each circuit was calculated. It shows. Therefore, the present invention experimentally confirms the maximum value of the magnetic flux density Bm of the second inductance _L2 , and as shown in FIG.
If the magnetic flux density Bm of L ₂ is set to 1.5 Wb/m ² or more, the short-circuit current will become too large, which will shorten the lamp life, cause the input current at startup to become too large, and worsen the fluctuation rate. It is something.
Note that FIG. 4 shows the experimental results when a 360W high-pressure sodium lamp was used as the lamp l, and the magnetic flux density Bm here shows an example when a general silicon steel plate is used as the iron core. In the figure, a shows the short-circuit current characteristics, and b in the figure shows the characteristics of the quick-down rate of the power supply voltage when the lamp goes out. In addition, the lower limit of the above magnetic flux density Bm is 0.8Wb/m ²
The reason for this is that when the temperature is less than this, the lamp life will be shortened and, as mentioned above, the turning-off characteristics of the lamp will deteriorate. In other words, FIG. 5 shows that the magnetic flux density is large (Bm=1.35Wb/
m ² ) case a, where the magnetic flux density is also small (Bm=
0.8Wb/m ² ) is denoted by b, and the case of the conventional circuit shown in Fig. 1 is denoted by c. The characteristic diagram of the lighting circuit in which the lamp characteristics are denoted by d is shown, and as is clear from this Fig. 5. When the magnetic flux density is increased, the short-circuit current increases, and the increase in lamp voltage is suppressed to a smaller level than when the magnetic flux density is decreased, and as shown in Figure 8, the turn-off performance of the lamp l with a high lamp voltage is improved. You can get it. In the example circuit shown in FIG. 2, even if the magnetic flux density of the inductance _L2 is increased, the desired effect can be achieved without deteriorating the voltage fluctuation characteristics by keeping the magnetic flux density of the inductance _L1 low. It is something to play. Since the present invention is configured as described above, the lamp is less likely to go out due to a quick down of the power supply voltage, and has the effect of always providing a stable lighting condition, and moreover, unlike the leakage transformer type lamp, Since there is no need to increase the volt-ampere of the circuit, the cost is extremely low, and even when the lamp voltage becomes high at the end of its life, it prevents the lamp from turning off due to the aforementioned power supply voltage quick-down. The short-circuit current is about the same as that of the conventional single-chitch yoke type, so the lamp does not take a long time to stabilize when starting.
Further, it has the effect of not having any adverse effect on the lamp life, and also has the effect of suppressing the increase in lamp voltage during the lamp life. In other words, the effects of the present invention can be demonstrated through experimental results as shown in the table below, which shows that even when the lamp voltage increases at the end of the lamp's life, it is difficult for the lamp to turn off due to a quick down of the power supply voltage. This is something that can be understood.

[Table] Here, a 360W high-pressure sodium lamp is used as the lamp, and it is lit with a 200V, 60Hz power supply, and the impedance of the first inductance, second inductance, and capacitor relative to the steady current is 14Ω, 30Ω, 156Ω respectively
is set to .

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional example, Fig. 2 is a circuit diagram of an embodiment of the present invention, Fig. 3 is a characteristic diagram comparing the lamp extinguishability due to quick-down of the power supply voltage with the conventional example. is a characteristic diagram showing the relationship between the quick-down rate of the power supply and the short-circuit current of the circuit when the power supply is turned off with respect to the magnetic flux density of the second inductance as above, and FIG. 5 is a characteristic diagram comparing it with the conventional example as above, L ₁ is the first inductance, L ₂ is the second inductance, C is the capacitor, and l is the lamp.

Claims (1)

[Claims] 1. A series closed circuit in which a first inductance, a second inductance, and a lamp that is a saturated vapor pressure discharge lamp such as a high-pressure sodium lamp are sequentially connected in series and both ends are connected to a commercial power source; A discharge lamp lighting circuit is formed by the second inductance and a capacitor connected in parallel to the series circuit of the lamp, and the magnetic flux density of the second inductance is
A discharge lamp lighting circuit characterized in that the circuit is set to 1.5Wb/m2 or ^less . 2 Set the lower limit of the magnetic flux density of the second inductance to
The discharge lamp lighting circuit according to claim 1, wherein the discharge lamp lighting circuit is set to 0.8 Wb/m ² or more.