JPS62100999A - Luminance controller of discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD The present invention relates to a dimming device for a discharge lamp, such as a fluorescent lamp, for performing dimming control by controlling the phase angle of a discharge lamp.

BACKGROUND ART A typical prior art is shown in FIG. This light control device 1 includes an AC power supply 2, a semiconductor switching element 3 whose phase angle is controlled (hereinafter referred to as a switch), a control circuit 4 for controlling the phase angle of the triac 3, and a rapid start type stable switching element 3. The output waveform of one line 11 of the AC voltage f22, which includes the TRIAC 5 and the discharge lamp 6, is 1] as shown in FIG. The output waveform of the line 13 connecting the ballast 5 and the discharge lamp 6 is as shown in FIG. 7(3).

In such prior art, the input voltage waveform may become distorted as shown in FIGS. 8(1) to (3) due to the dimming load. For such a distorted input voltage,
If the discharge lamp is dimmed in the same phase as the distorted phase, it will be affected by the distortion of the voltage applied to the ballast 5, and if it is not distorted, that is, in the case of Fig. 7 (1) to Fig. 7 (3) This results in a lower rise voltage. Therefore, the ignition pulse in the ballast 5 becomes smaller, and the discharge lamp 6 becomes α
It becomes difficult to light the lamp, and the current flowing through the discharge lamp 6 also decreases.
This results in low illumination levels. Furthermore, the decrease in illuminance due to this ignition pulse phenomenon is much larger than the decrease in power due to distortion of the input terminal waveform, and
In the region of 0 degrees or more, the illuminance before and after the distorted phase angle is significantly different. This prevents a mutual interference in which the discharge lamp 6 becomes dark when the phase angle of the dimmer circuit changes, which causes the input voltage to be distorted, and becomes the same as the phase angle of the discharge lamp 6. There is a problem in that this occurs and causes discomfort to the user.

Purpose The principal's proposal is to solve the above-mentioned technical problems, and to ensure stable phase angle control for discharge lamps even if the waveform of the AC power source is undesirably distorted, so that the illuminance does not change. It is an object of the present invention to provide a dimmer device for a discharge lamp which is capable of doing the following.

Example FIG. 1 is a block diagram of one embodiment of the present invention.

The light control device 10 according to the present invention basically consists of an AC power source 11
and a semiconductor switching element (hereinafter referred to as a triac) 13 which is interposed between the discharge lamp 12 and whose phase angle is controlled, and a capacitor 14 connected in parallel to the AC power supply 11.
Before the triac 13 is made conductive, a voltage higher than the voltage when the triac 13 is made conductive is held in the capacitor 14, and after the triac 13 is made conductive, the electric charge of the capacitor 14 is supplied to the discharge lamp 12 side via the triac 13. 〃Includes a generation circuit 28 and a ballast 18.

The ballast 18 is basically a rabbit start type lighting circuit, and the phase-controlled output voltage of the dimmer 20 is applied to the primary side of the leakage transformer 19. Preheat Y
The lance 2 always preheats the heater, which also serves as the discharge electrode of the discharge lamp 12, with a constant voltage, regardless of the dimming state. The stabilizer 18 also has a pulse generating circuit 2.
2 is provided, and by superimposing a narrow high-voltage pulse on the voltage waveform of the discharge lamp 12 at the time of re-ignition of each cow cycle, it is possible to prevent flickering, no jump, ring running, etc. of the discharge lamp 12 at low illuminance. It acts as a preventive measure.

The preheat line /10 of the ballast 18 is connected to one side of the AC power supply 11. Also, the common line for ballast 18! 1
1 is connected to the other side of the AC power supply 11. The connection point 23 of the preheating line 110 is connected to the fin J! The connection point 25 of the parallel circuit with the thyristors THI and TI (2) is connected via the semiconductor switching element 13 to the connection point 24 of the parallel circuit with the thyristors THI and TI (2). !
13. Connection point 26 between connection point 25 and triac 13 and common line! A capacitor 14 is interposed between the 11 connection points 27. Thyristor TH
I, TH2 and triac 13 have fins 714
, 715. J! Tri-pulse generation circuit 28 via 1G
A pulse is applied to each pulse, and each phase angle control is performed using this pulse. The trigger pulse generation circuit 28 connects the fingers 17 to the connection points 29 and 30 on both sides of the AC power supply 11.
．． ) 18, thus constituting the light control device 10 according to the invention.

The pulse generation circuit 28 is line! In the half-period in which finger 12 is positive, the high-level bird leaves the signal on the date of thyristor THI, and in the negative half-period of finger 12, the high-level bird leaves the signal on the thyristor T I 2. Leave as given. Hence the line! In the half cycle where 12 is positive, the date of thyristor TH2 is up to the low level book, and the line! In the negative half cycle of 12, the date of thyristor THI remains low. In this way, thyristors THI and TH2 are alternately turned on in the positive half cycle and the negative half cycle. The conduction of the thyristor THI in the positive half-cycle therefore charges the capacitor 14, so that when the transistor 13 conducts, the finger 1 of the ballast 18
Power can be supplied to 3. Further, in the negative half cycle, only the thyristor TH2 is conductive, thereby charging the capacitor 14, and power can be supplied to the line 13 of the ballast 18 in the same manner as described above.

FIG. 2 is an output waveform diagram when no distortion occurs in the input voltage, and FIG. 3 is an output waveform diagram when distortion occurs. Figure 2 (1) Upper V Figure 3 (1) shows AC power supply 1
FIG. 2 (2) and fjSU diagram (2) are output waveform diagrams of the capacitor 14, and FIG.
3) and FIG. 3(3) are output waveform diagrams of the two-in-one 13 of the ballast 18, and FIG. 2(4) and FIG. 3(4) are output waveform diagrams given to the discharge lamp 12. T below! t
The operating status will be explained with reference to Table J1.

(Margins below) Table 1 First, line! Assume that 12 is a positive half period. At this time, the pulse generation circuit 28 is 2 in.
! 15 is still given a high level signal, and the line! 14 remains supplied with the low-level triff signal. First, when the phase angle α is O and α≦α1, as shown in FIG. 2 (2) and FIG. 3 (2), the capacitor 14 is charged with a primary phase angle α of α1<
When α≦α2, the input voltage ■0 becomes t3 lower than the voltage ■1 of the capacitor 14, so the thyristor TH1 is turned off. Therefore, during this period, the charge on the capacitor 14 remains held.

Next, when the phase angle α becomes α2, a triac pulse from the pulse generating circuit 28 is applied to the triac 13, thereby turning the triac 13 on.
Stable 418 line from capacitor 14! 13, the waveform portion P1 of FIG. 2(3) and the waveform portion Pla of FIG. 3(3) are supplied. Eventually, the capacitor 14 is discharged, and the power from the AC power source 11 is transferred to the line of the ballast 18! 1
3, the waveform portion P2 of Fig. 2 (3) and Fig. 3 (3)
As shown by the waveform portion 9 P 2 a, power is supplied. When the phase angle α becomes a J, that is, at the zero crossing of the AC waveform, the triac 13
and thyristor T H1 are both turned off. In this way, the outputs T and ipa shown in FIG. 2(4) are given to the discharge lamp 12.

Next, assuming that the line 12 has a negative half cycle, the trigger pulse generating circuit 28 applies a high level pulse to the fin 14, and a low level pulse to the line 715. As a result, thyristor TH1 becomes OFF state, and thyristor TH2
is in the ON state. When the phase angle α is a3<α≦α4, the thyristor TH2 is in the ON state, and the capacitor 1
4 is full 1! be done. Next, when the phase angle α is a4<a≦a5, line! 120 input voltage V1 is capacitor 14
The voltage of TH2 becomes lower than 1, so thyristor TH2
The state becomes FF. Thereafter, when the triac 13 is turned on in the case of phase angle α=α5, as shown in FIG.
) reference tf-Ql and reference mark Q 1 in FIG. 3(3)
The waveform component indicated by a is the line node 13 of the ballast 18.
However, eventually the capacitor 14 is discharged, and power from the line 11 is supplied to the line 13. After that, when the phase angle α=α6,
The triac 13 and the thyristor TH2 are turned off, and the discharge lamp 12 receives an output T shown in FIG. 3 (4).
, ipa are given, and the above series of operations is repeated.

In this way, when the phase angle α2 (α5) is smaller than 90 degrees, when the triac 13 is turned on, the voltage peak value from the capacitor 14 is instantaneously input to the ballast 13, so that the ballast 18 The operation of the ignition pulse generating circuit 22 increases the ignition pulse, thereby making it easier to light the discharge lamp 12. Furthermore, as shown in FIG. 3, even if the voltage of the two-current power supply 11 is distorted during lighting, the capacitor 14 can prevent the ignition pulse from being affected.

According to experiments by the inventor of the present invention, when the phase angle is between 0 degrees and 90 degrees and between 180 degrees and 270 degrees, when the triac 13 is turned on, the power supply voltage is raised to f! , the discharge lamp 12 tends to be discharged and therefore lit stably, and the illuminance is relatively high (even if the input voltage is distorted, flickering is less likely to occur. Also, the phase angle 9
When the triac 13 is turned on in the range of 0 degrees to 180 degrees and 270 degrees to 360 degrees,
The illuminance is relatively low and therefore flicker is more noticeable due to the effects of input voltage distortion. Therefore, in accordance with the present invention, a capacitor 14 is used to
By eliminating '#iff, flickering can be made less noticeable and illuminance can be stabilized.

FIG. 4 is a block diagram of another embodiment of the present invention. In this embodiment, the preheating line 10 and the common line! A diode D1 and a capacitor C1 are connected between the connection points 30 and 31 with 11.
Connect the series circuit with.

In addition, a diode D is connected between t'f, 32, and 51.
2 and the capacitor C2, and the connection point 50 between the diode D1 and the capacitor C1 and the line of the ballast 18! 12 connection, between Hiro 33, Cyrisk T
A thyristor T H4 is interposed between the connection between the diode D2 and the capacitor C2, α34, and the connection point 33 indicated by +if.

When the power supply voltage is in the positive half cycle, the charge from capacitor C1 holding that voltage is input to the ballast 18 via the cyrisk TH'3. Also, during the negative half cycle, the charge in the capacitor C2 is transferred to the thyristor T H4.
is supplied to the ballast 18 via.

The operating state will be explained below with reference to FIG.

First, when the phase angle α is O<α≦a1, the diode D
1, the capacitor C1 is charged as shown in FIG. 5(2). Next, when the phase angle a is αt<a≦2, the capacitor C2 keeps its peak value P. When the phase angle α=α2, the thyristor TH3
is turned on, and the charge from the capacitor C1 is supplied to the stabilizer 18. Eventually, capacitor C1 discharges,
Power from the AC power supply 11 is now supplied. Then, at phase angle α=a3, thyristor T H3 is OF
It becomes F state.

Similarly, when the phase angle a is α3<17≦a4,
Capacitor C2 is charged via diode D2.

Next, when the phase angle α is α4 and α≦α5, the capacitor C2 holds the peak value Pa of the power supply voltage, as shown in FIG. 5(3). When the thyristor T IT 4 #f turns ON at the position MJ /l) α=α5, the voltage of the input voltage peak value is instantaneously supplied from the capacitor C2, and the capacitor C2 is eventually discharged, and the AC power supply 1
1 is supplied to the ballast 18. Then, at the phase angle a=a6, the thyristor TH4 is in the OFF state.

Even if the waveform of the voltage of the AC power source 11 is distorted by repeating such an operating state, as in the previous embodiment, stable phase control is performed for the discharge lamp 12 so that the illuminance does not decrease. It becomes possible to do so.

In this way, by adding a capacitor that holds the power supply voltage peak value to the conventional dimming position yIc, the phase angle can be increased to 9
Since it becomes possible to generate a large ignition pulse even in the region of 0 degrees or more, it is possible to improve the dimming characteristics at low illuminance.

Furthermore, in the conventional design, a sufficiently large pulse is output in a region where the phase angle is large, so a considerably large pulse is generated when the phase angle is around 90 degrees. In the present invention, electric '12
By providing a capacitor that holds the voltage peak value, an ignition pulse of a constant voltage can be generated even in a region where the phase angle is 90 degrees or more. Therefore, there is no need to create an unnecessarily large ignition pulse, and safety is ensured. Furthermore, even if distortion occurs in the power supply voltage, it is possible to prevent the ignition pulse from becoming smaller due to this distortion (in the phase angle region of 90 degrees or more), so the degree of illuminance change due to the distortion can be significantly reduced. I can do it.

Effects As described above, according to the present invention, capacitors are connected to an AC power source in an "L" row, a semiconductor switching element whose phase angle is controlled is interposed between the AC power source and the discharge lamp, and the triac is made conductive. First, a voltage higher than the voltage when the semiconductor switching element is turned on is held in the capacitor, and after the semiconductor switching element is turned on, the charge in the capacitor is supplied to the discharge lamp side via the semiconductor switching element. With this, is it second class? Even if the waveform of r1'fi is undesirably distorted, it is possible to stably control the phase angle of the discharge lamp, and therefore it is possible to prevent the illuminance from decreasing.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an instant embodiment of the present invention, FIGS. 2 and 3 are output waveform diagrams related to FIG. 1, FIG. 4 is a block diagram of an embodiment of the present invention, and FIG. The output waveform diagrams related to FIG. 4 and FIGS. 6 to fjS8 are diagrams for explaining the prior art. 10... Light control device, 11... AC power supply, 12... Discharge lamp, 13... Triac, 14. ct, c2...
・Capacitor, 18...Ballast, 28...F Pulse generation circuit Agent Patent attorney Number of strokes Keiichibe No. 284 Figure 3 Figure 5 Figure 6 Figure/'' Section 7 Figure 8

Claims (1)

[Scope of Claims] An AC power supply, a discharge lamp, a semiconductor switching element interposed between the AC power supply and the discharge lamp and whose phase angle is controlled, a capacitor connected in parallel to the AC power supply, and a semiconductor switching element a control circuit that causes the capacitor to hold a voltage higher than the voltage at the time of conduction prior to conduction, and supplies the charge of the capacitor to the discharge lamp side via the semiconductor switching element after the semiconductor switching element is conductive. A discharge lamp dimmer device characterized by: