JPH0119640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device capable of dimming lighting by phase control.

2. Description of the Related Art Techniques for dimming and lighting a discharge lamp using phase control are conventionally known. For example, a method has been proposed in which a high-voltage pulse is superimposed on every half cycle of a phase-controlled power supply voltage to re-ignite the discharge lamp. This item can be dimmed fairly deeply, but
It is necessary to add a device for generating the above-mentioned high-voltage pulses to the stabilizer, and therefore there is a drawback that it cannot be realized with a general stabilizer. Another conventional device has been proposed in which a bypass impedance is provided in parallel to the phase control device so that current is supplied to the discharge lamp even during the non-conducting period of the phase control device. However, this method has the disadvantage that the impedance changes depending on the load, that is, the number of stabilizers and discharge lamps, and therefore the current flowing in during the non-conducting period changes and the brightness of the discharge lamp is not constant. .

The present invention has been made in order to eliminate the drawbacks of the conventional devices as described above, and there is no need to add special restriking means to the stabilizing device, and therefore, a stabilizing device for general lighting can be used. Moreover, it is an object of the present invention to provide a discharge lamp lighting device which is capable of considerably deep dimming lighting and whose brightness does not change even if the number of loads changes.

The present invention provides a discharge lamp regardless of the number of stabilizers and discharge lamps by supplying an attenuated voltage having a peak value at the beginning of the non-conducting period by an auxiliary power source during the non-conducting period of the phase control device. This feature is characterized in that a minute current is passed through the phase control voltage to substantially eliminate restriking when a phase control voltage is applied.

Hereinafter, the basic configuration of the present invention will be explained with reference to FIGS. 1 and 2. 1 is a discharge lamp, such as a fluorescent lamp or a high-intensity discharge lamp. Reference numeral 2 denotes a stabilizer for the discharge lamp 1, which has at least inductive impedance. As such a stabilizing device 2, for example, one having a leakage transformer and a capacitor, one having a chiyoke coil and a capacitor, one having only an inductive impedance, etc., which are conventionally known for general lighting, are available. Can be used. One or more series circuits of the discharge lamp 1 and the stabilizer 2 are provided in parallel. Reference numeral 3 denotes a phase control device, which controls the phase of the voltage of a power source 4, for example, a commercial AC power source, and supplies it to the discharge lamp 1 via the stabilizer 2, which includes triac, SCR,
It is constructed using a combination of a diode bridge and a transistor, or even other switching elements. 5 is this phase control device 3
This conduction control device is configured to correspond to the configuration of the phase control device 3, and well-known techniques can be used for both. Next, 6 is an auxiliary power source. During the non-conducting period of the phase control device 3, this auxiliary power supply 6 supplies an attenuated voltage having a peak value at the beginning of the non-conducting period to the discharge lamp 1 through at least the inductive impedance of the stabilizer 2. It is something. For example, it supplies the differential waveform voltage shown by b in FIG. 2A. Here, stabilizer 2
The expression "via at least inductive impedance" means, for example, that when the stabilizer 2 has a single-turn leakage transformer, the attenuated voltage can be supplied without passing through the primary winding. Note that a in FIG. 2A indicates the output voltage of the phase control device 3. A control device 7 controls the voltage supply from the auxiliary power source 6 to the discharge lamp 1, and controls the auxiliary power source 6 by detecting whether the phase control device 3 is turned on or off.

Next, the effect will be explained. When the voltage shown in FIG. 2A is supplied, the lamp current becomes zero at t ₁ as shown in FIG. 2B, and the discharge lamp 1 is temporarily turned off. However, at this time _t1 , a high voltage (peak value) is supplied by the auxiliary power supply 6. In this case, if the stabilizer 2 has a phase advance capacitor, the charge charged in this capacitor in the previous half cycle is superimposed on the voltage of the auxiliary power source 6 and applied to the discharge lamp 1. Therefore, the peak value of the auxiliary power source 6 is selected depending on the presence or absence of the phase advance capacitor and the charging voltage of the capacitor, but in any case, the discharge lamp 1 is
It is immediately re-ignited at t ₁ , and current begins to flow through the discharge lamp 1 in the opposite direction to that of the previous half cycle. but,
Since the voltage from the auxiliary power supply 6 is then attenuated, the lamp current does not increase, and the current holding effect of the inductive impedance in the stabilizer 2 causes a substantially constant lamp current to flow. During this time, the lamp current is regulated to a minute current that hardly contributes to light emission. Such regulations can be designed taking into consideration the output voltage waveform of the auxiliary power supply 6, the inductive impedance in the stabilizer 2, the presence or absence of a phase advancing capacitor, the equivalent resistance of the discharge lamp 1, etc. Next, when a phase control voltage is supplied at t ₂ , the lamp current increases and the discharge lamp 1 generates a predetermined light output. In this way, the discharge lamp 1 is re-ignited by the voltage of the auxiliary power supply 6 during the non-conducting period of the phase control device 3, and since a small lamp current is continuously flowing, the phase control voltage is Therefore, there is no need to re-ignite. In other words, by creating a pause period in the lamp current, the restriking voltage becomes high, making restriking impossible or unstable with the phase control voltage, causing flickering in the light output. There is no. Moreover, it will be understood from this that the degree of dimming can be considerably increased. Note that if the voltage supplied by the auxiliary power source 6 is constant during the non-conducting period of the phase control device 3 or increases with time, the lamp current increases and contributes to light emission, making it impossible to obtain the desired dimming. It is something.

FIG. 3 shows a specific configuration of an embodiment of the present invention. Components corresponding to those in FIG. 1 are given the same reference numerals and their explanations will be omitted. The auxiliary power supply 6 has a pair of capacitors 601 and 602, and one end of each is connected to the power supply 4.
are commonly connected to one output terminal of the Also,
Rectifier diodes 603, 6 with opposite polarity at the other end
04, current limiting inductors 605, 606 and first switching transistors 6 with opposite polarities
07, 608 to the input terminal side of the phase control device 3, and furthermore, second switching transistors 609, 610 having mutually opposite polarities and backflow prevention diodes 611, 6 also having opposite polarities.
12 to the output terminal side of the phase control device 3. The first switching transistors 607 and 608 are controlled by a signal generator 613 that outputs an on signal in response to the output signal of the conduction control device 5. This signal generator 613 includes a monostable oscillator 614 that inputs the signal from the conduction control device 5, a transistor 615 that is turned on by the output of this oscillator 614, and a pair of light emitting diodes 616 and 617 that are connected in series with the collector of this transistor 615. The first switching transistors 607 and 608 are controlled by the light emitting diodes 616 and 617. The control device 7 has a pair of anti-parallel connected light emitting diodes 701 and 702 provided between the input and output terminals of the phase control device 7. This is to control the switching transistors 609 and 610 of No. 2. That is, when the phase control device 3 is in a non-conducting period, a voltage is applied across the light emitting diodes 701 and 702, and the light emitting diodes having the same polarity as the power supply voltage emit light, which causes one of the second switching transistors to be activated. Turn it on. However, this control device 7 can also be responsive to the output current of the phase control device 3 or can be preset by the phase control device 3.
A signal indicating the non-conducting period of the conduction control device 5 may be generated in conjunction with the conduction control device 5. Since the discharge lamp 1 and the stabilizer 2 are the same as those described in connection with FIG. 1, their explanations will be omitted. Furthermore, since the conduction control device 5 has a well-known configuration, a description thereof will be omitted. However, it goes without saying that the conduction control device 5 is not limited to the one shown in FIG.

Next, the operation will be described with reference to FIG. FIG. 4A shows the output voltage of the power supply 4. When the conduction control device 5 outputs a signal with a preset phase (FIG. 4B), the output of the phase control device 3 becomes as shown in FIG. 4C. In other words, the inductive impedance of the stabilizer 2 causes a delayed current, and the phase control device 3
The conduction phase of does not match the phase of the power supply voltage. During the non-conducting period of the phase control device 3, the light emitting diodes 701 and 702 of the control device 7 alternately emit light (FIG. 4 D and E), and the second switching transistors 609 and 610 of the auxiliary power source 6 are alternately turned on. let
Therefore, the pair of capacitors 60 of the auxiliary power supply 6
1 and 602 are controlled by second switching transistors 609 and 610, respectively, and are alternately discharged (FIGS. 4G and 4H). In this case, the polarity of the power supply voltage matches the polarity of the voltage across the capacitor being discharged. As a result, stabilizer 2 and discharge lamp 1
A composite voltage (FIG. 4J) of the phase control voltage of FIG. 4C and the discharge voltage of the capacitors 601 and 602 of FIG. 4I is applied to the series circuit of FIG. On the other hand, in response to the output of the conduction control device 5, the signal generator 613 of the auxiliary power supply 6 outputs the signal shown in FIG.
A pair of capacitors 601 and 602 are charged according to the polarities of 07 and 608 and the polarity of the power supply voltage (FIG. 4G and H), and are ready for the next discharge. The lighting characteristics of the discharge lamp 1 are the same as those described in connection with FIG. 1, so the description thereof will be omitted. In addition, in the case of a device having a capacitor as an auxiliary power source as in this embodiment, a diode 618 is connected between both terminals of the capacitor with the polarity opposite to that of the charged charge.
Providing 619 has the following effects. That is, during the non-conducting period of the phase control device 3, when the voltage between the terminals of the capacitors 601 and 602 in the auxiliary power supply 6 decreases, the charge accumulated in the capacitance component of the stabilizer 2 is transferred to the diodes 618 and 619.
This allows discharge to occur through the discharge lamp 1 and supply power to the discharge lamp 1.

Next, the experimental results by the present inventors are shown in FIG. In FIG. 5, the horizontal axis shows the firing phase angle of the phase control device, and the vertical axis shows the specific luminous flux. Furthermore, the fifth
The one in the picture consists of two 110W fluorescent lamps (FLR110H/A manufactured by Toshiba) connected in series as a discharge lamp, and a leakage transformer and a phase advance capacitor as a stabilizer (FRH-2-96216A manufactured by Toshiba Denzai).
(starting capacitor connected in parallel with one lamp out of two lamps in series), three series circuits of the above discharge lamps and stabilizers are connected in parallel, and the power supply is
The 200V, 50H, auxiliary power supply waveform is similar to Figure 4 J, and is for the case where the peak value is 150V.
Similar results were obtained even when the conditions were changed. however,
The peak value of the auxiliary power source cannot be made very low due to its relationship with the restriking voltage of the discharge lamp. In FIG. 5, A shows a device equipped with an auxiliary power source according to the present invention, and B shows a device without an auxiliary power source. As is clear from FIG. 5, according to the present invention, flickering and unstable lighting conditions of the discharge lamp can be eliminated, the degree of dimming can be deepened, and a smooth dimming curve can be obtained. Therefore, it greatly contributes to power saving.

Note that the present invention is not limited to the above embodiments. For example, the power source may be a triangular wave instead of a sine wave. In addition, the auxiliary power supply does not necessarily have to supply a differential waveform voltage; for example, when the firing angle of the phase control device is relatively early in phase, it may supply a pulse voltage as shown in Fig. 6. good. Even when outputting a differential waveform, a control means such as a dropper that reduces the output voltage over time may be used instead of utilizing the discharge characteristics of the capacitor. Also, there is no need to supply the peak value portion at the same time as the phase control device turns off.
As long as the re-ignition voltage of the discharge lamp does not rise significantly, the peak value portion may be supplied after a short time after the phase control device extinguishes the lamp. Furthermore, the specific configuration of the auxiliary power source may include, for example, a battery or a power transformer. Any device that can supply an attenuated voltage may be used.

As detailed above, the present invention supplies an attenuated voltage having a peak value at the beginning of the non-conducting period to the discharge lamp during the non-conducting period of the phase control device through at least the inductive impedance of the stabilizer. By doing so, the discharge lamp continues to pass a small lamp current,
Since there is no need to re-ignite using a phase control voltage, there is no need to install a special pulse generator, and the discharge lamp will not become impossible to re-ignite or become unstable, so the flickering of the light will be reduced. It is possible to provide a discharge lamp lighting device that is capable of deep dimming lighting without unstable states such as the above.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.
Fig. 2 is a waveform diagram for explaining the action of Fig. 1;
Fig. 3 is a circuit diagram showing an embodiment of the present invention, Fig. 4 is a waveform diagram to explain the action of Fig. 3, Fig. 5 is a characteristic diagram showing experimental results, and Fig. 6 is a circuit diagram showing an embodiment of the present invention. FIG. 7 is a waveform diagram of another example. DESCRIPTION OF SYMBOLS 1... Discharge lamp, 2... Stabilizer, 3... Phase control device, 4... Power supply, 5... Continuity control device, 6... Auxiliary power supply, 7... Control device.

Claims (1)

[Claims] 1. A stabilizer having inductive impedance and provided in series with the discharge lamp, a phase control device provided between the stabilizer and the power supply, and a non-conducting period of the phase control device. A discharge lamp lighting device comprising: an auxiliary power source that supplies an attenuated voltage having a peak value at an initial peak value during a non-conducting period to the discharge lamp through at least an inductive impedance of the stabilizer. . 2. The discharge lamp lighting device according to claim 1, wherein the auxiliary power source supplies a differential waveform voltage to the discharge lamp via the stabilizer. 3. The discharge lamp according to claim 1 or 2, wherein the auxiliary power source includes a capacitor charged by the power source and a switching element that controls discharging of the capacitor. lighting device. 4. The discharge lamp lighting device according to claim 1, wherein the auxiliary power supply supplies a pulse voltage to the discharge lamp via the stabilizer at an early stage during a non-conducting period of the phase control device. . 5. The discharge lamp lighting device according to claim 3, characterized in that a diode having a polarity opposite to the charge charged in the capacitor is connected between both terminals of the capacitor.