JPS6115558B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device, and more particularly, to an improved discharge lamp lighting device that can significantly reduce the size of the current limiting choke and improve the fluctuation rate of the tube current in, for example, an every-cycle start lighting method. Regarding.

The present applicant has previously proposed an every-cycle start lighting method that not only improves efficiency but also makes it possible to reduce the size and weight of the current limiting choke, and is extremely effective in saving resources and energy.

FIG. 1 is an electric circuit diagram showing an electric lamp lighting device using an every-cycle start lighting method, which is the background of the present invention. In the configuration, reference numeral 1 denotes an AC power source, to which a series circuit of a current limiting choke 2 as an example of a current limiting device and a discharge lamp 3 is connected. An intermittent high frequency high voltage generating circuit (hereinafter referred to as a high voltage circuit) 4 is connected to the non-power supply side of the filaments 31 and 32 of the discharge lamp 3.

The high voltage circuit 4 is a circuit in which an intermittent oscillation capacitor 6 is connected in series to a high frequency high voltage generating circuit (hereinafter referred to as a boost circuit) 5, which is configured by connecting an oscillation capacitor 51, a series circuit of a thyristor 52, and a boost inductor 53 in parallel. .

As long as the high-voltage circuit 4 performs intermittent high-frequency oscillation, it may be replaced with a high-voltage generating circuit using a gated thyristor such as a triac, or even an inverter.

FIG. 2 shows waveforms of various parts during lighting observed as a result of calculations using the equivalent circuit of the circuit of FIG. 1, with high frequency components ignored except for FIG. 2D.
The operation of the above configuration will be described below with reference to this waveform diagram.

When the power supply 1 is turned on, a power supply voltage e as shown in FIG. 2A is applied to the discharge lamp 3 via the current limiting choke 2.
is applied, and the power supply voltage e is applied to the high voltage circuit 4.
is applied. In the high voltage circuit 4, the power supply voltage e is applied to the thyristor 52 via the intermittent oscillation capacitor 6, and the booster circuit 5 starts an oscillation operation to cause the thyristor 52 to break over. This oscillation operation would continue without the intermittent oscillation capacitor 6, but as the booster circuit 5 oscillates, the intermittent oscillation capacitor 6 is gradually charged, and the terminal voltage of the intermittent oscillation capacitor 6 increases. By canceling out the power supply voltage, the power supply voltage e oscillates intermittently every half cycle during the rising portion of the power supply voltage e. Therefore, this booster circuit 5 generates an intermittent oscillation output at every predetermined phase of each half cycle of the AC power supply voltage e.

This oscillation output is superimposed on the power supply voltage e and applied to the discharge lamp 3. At the same time, the input current i _R of the high voltage circuit 4 flows through the path of power source 1 - current limiting choke 2 - filament 31 - high voltage circuit 4 - filament 32 - power source 1.

When the filaments 31 and 32 are thus preheated, the discharge lamp 3 is started by being triggered by the oscillation output v _R from the high voltage circuit 4. When the discharge lamp 3 is lit, the discharge lamp 3 as shown in FIG.
When the tube current _T flows through the current limiting tube 2, its impedance changes and the input current i
The appearance period of _R is shorter than during preheating. Of course, during the rest period of the input current i _R , the high voltage circuit 4 stops its oscillation operation, and therefore, during the lighting of the discharge lamp 3 in each half cycle, the preheating current based on the input current i _R decreases. Further, during the pause period of the input current i _R , preheating of the filaments 31 and 32 is stopped. Thereafter, the discharge lamp 3 is lit again by the oscillation output v _R of the high-voltage circuit 4 every half cycle of the power supply 1, and is maintained lit by the power supply voltage e.

Here, the tube voltage v _T becomes a rectangular wave with a rest period due to an intermittent oscillation period, as shown in Fig. 2B, and its effective value V _T is a value that is slightly lower than that of the conventional lighting method. show. Furthermore, as the intermittent input current i _R of the high voltage circuit 4 as shown in FIG. 2E flows through the current limiting choke 2, the waveform of the tube voltage v _T changes as shown _in FIG. 2B. It is slightly increased due to the influence of The appearance phase of the input current i _R is constant regardless of fluctuations in the power supply voltage, and therefore the tube current i
The rising phase of _T is kept constant regardless of fluctuations in the power supply voltage e. Moreover, the input current i _R is
If the tube current i _T increases due to an increase in the power supply voltage, there is a characteristic that the trailing end of the tube current i _T waveform embeds the appearance period of the input current i _R in the next half cycle, thereby decreasing it. That is, it has a negative coefficient of variation. These are the reasons why the fluctuation rate of the tube current i _T in the every-cycle start lighting method is maintained well regardless of the decrease in the specified impedance.

_The instantaneous _{reactive power (} v _CH
i) and the significant energy S are calculated, resulting in the waveforms shown in F and G in the figure. That is, in the figure F, S ₁ is the input current i _R during the oscillation period (t1 to t2)
S ₂ is the energy significantly accumulated by the tube current i _{T during the period (t2 to t3) when the power supply voltage e is higher than the tube voltage v T ,} and S ₃
is the period during which the tube voltage v _T is higher than the power supply voltage (t3 to t
4) is the energy released by the tube current i _T , and the relationship S ₁ +S ₂ =S ₃ holds true.

If we calculate the significant energy and required inductance of the current-limiting choke 2 based on the waveform shown in Fig. 2, they will be about 4/1 and 1/5 of the conventional glow lighting system, respectively, and the size will be reduced accordingly. can do.

Note that the size reduction ratio becomes even more remarkable when compared with a rapid start type ballast having a step-up transformer configuration.

Furthermore, according to such a lighting method, the power supply voltage e
Since the phase difference between the tube current i T and the tube current i _T is smaller than that in the conventional lighting system, a power factor correction capacitor is not required or the capacitance can be made extremely small.

As described above, the cycle-by-cycle lighting method, which is the background of the present invention, has great advantages in terms of resource and energy saving compared to conventional lighting methods, and also has a superior fluctuation rate of tube current, which is superior to conventional lighting methods. This has the advantage that the ballast can be made smaller. However, as the current limiting choke is made even smaller to a critical point, the rate of variation tends to worsen.

Therefore, the main object of the present invention is to provide a discharge lamp lighting device that can significantly reduce the size of the current limiting choke and also prevent the fluctuation rate from worsening due to fluctuations in the fluctuation factors of the tube current. .

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

To summarize this invention, a discharge circuit is connected in parallel to an intermittent oscillation capacitor included in an intermittent high-frequency high-voltage generating circuit in an every-cycle start lighting system, and By controlling the discharging operation timing of the discharging circuit based on fluctuations in the tube current itself (e.g., yoke voltage, etc.) or fluctuations in the tube current itself, the charge in the intermittent oscillation capacitor is discharged, and the phase of the intermittent oscillation start timing can be varied for each cycle. By doing so, the fluctuation rate of the tube current is substantially improved.

FIG. 3 shows an electrical circuit diagram illustrating the principles of the invention. In the configuration, an AC power supply 1 is connected to a series circuit of a current limiting choke 2 and a discharge lamp 3 as an example of a current limiting device. An intermittent high frequency high voltage generating circuit (hereinafter referred to as a high voltage circuit) 4 is connected in parallel to the discharge lamp 3. This high voltage circuit 4 includes an oscillation capacitor 51 connected to the power supply side ends of the filaments 31 and 32 of the discharge lamp 3, a step-up inductor 53 connected to the non-power supply side of the filaments 31 and 32 of the discharge lamp 3, and a boost inductor 53 for intermittent oscillation. It consists of a series circuit of a capacitor 6 and a thyristor 52.
Note that the intermittent oscillation capacitor 6 is the thyristor 5.
2 and the boost inductor 53.

In parallel to the intermittent oscillation capacitor 6,
A discharge circuit 7 for an intermittent oscillation capacitor 6, which is a feature of the present invention, is connected. The discharge circuit 7 is composed of a series circuit of a discharge resistor 71 shown as an example of an impedance element and a triac 72 shown as an example of a switching element with a control electrode.
The output of a gate circuit 81 included in a control means 8 for controlling the discharge timing of the intermittent oscillation capacitor 6 based on the fluctuation factors of the tube current is applied to the anode electrode and gate electrode of the triax 72. Circuit 81 generates a gate signal in response to the output of comparison circuit 82. This comparison circuit 8
2 is inputted with a reference voltage V1 and a detection voltage V2 provided by detecting fluctuation factors in the tube current. Therefore, based on the reference voltage V1 and the detected output voltage V2 of the tube current fluctuation factor, the comparator circuit 82 issues a gate signal generation command signal to the gate circuit 81 in response to the detected voltage V2 becoming equal to or higher than the reference voltage V1. give. Therefore, the gate circuit 81
By applying a gate signal to 2 to make the triac 72 conductive and discharging the charge in the intermittent oscillation capacitor 6 via the discharging resistor 71 and the triax 72, the terminal voltage of the intermittent oscillation capacitor 6 is substantially lowered. , act to delay the oscillation start phase of the high voltage circuit 4. As a result, the tube current is controlled to a predetermined value even though the factors that cause the tube current to fluctuate have fluctuated.

In addition, as a factor of fluctuation of tube current, AC power supply 1
The input current from i is the tube current i _T , the high voltage circuit 4
If the input current to is i _S , the relationship i=i _T +i _S holds, so there are fluctuations in the input current due to voltage fluctuations in the power supply 1 and voltage fluctuations in the current limiting choke 2 . Therefore, as the detection voltage V2 based on the variation of the tube current variation factor of the comparator circuit 82, the output obtained by detecting the power supply voltage variation, the input voltage variation, the tube current variation, the choke voltage variation, etc. may be used. Therefore, specific circuit configurations and their operations will be explained below for each of the factors that cause fluctuations in pipe flow.

FIG. 4 is a practical circuit diagram of one embodiment of the present invention. This embodiment controls the discharge timing of the intermittent oscillation capacitor 6 based on the voltage fluctuation of the power supply 1, and includes a transformer 84 for detecting the voltage fluctuation of the AC power supply 1 and an output voltage of the transformer 84. A rectifier circuit 83 for rectification is provided.

Figure 5 shows the waveform diagram of each part in Figure 4, especially the 5th waveform diagram.
Figure A shows the power supply voltage e, Figure 5B shows the terminal voltage (charging voltage) V _C of the intermittent oscillation capacitor 6, and Figure 5 C shows the tube voltage V _T . In addition, A to C
The solid line in indicates the steady state, and the broken line indicates the power supply voltage fluctuation state. Next, referring to FIG.
The specific operation of the circuit shown in the figure will be explained.

When the AC power supply 1 is turned on, the oscillation capacitor 51 is charged via the current limiting choke 2. When the charging voltage of this oscillation capacitor 51 exceeds the breakover voltage of the thyristor 52, the thyristor 52
conducts, the oscillation capacitor 51 and the boost inductor 53 cooperate to perform high-frequency oscillation, and the oscillation current preheats the filaments 31 and 32. At this time, a voltage obtained by superimposing the power supply voltage e and the high frequency oscillation voltage is applied to both ends of the discharge lamp 3. Thus, when the filaments 31 and 32 are sufficiently preheated, the discharge lamp 3 is started and lit. At this time, since the intermittent oscillation capacitor 6 is inserted in the high frequency oscillation path, it is charged by the input current i _S to the high voltage circuit 4 and cancels out the power supply voltage e, thereby turning off the thyristor 52 and increasing the power supply voltage. The oscillation operation is performed intermittently at each predetermined phase of each half cycle of e.

Now, if the power supply voltage e does not fluctuate (the solid line shown in FIG. 5A is a steady state), a constant voltage will occur in the secondary winding of the transformer 84,
3 derives a detection voltage V2 obtained by rectifying the secondary induced voltage of the transformer 84 and a reference voltage V1 created by making the rectified voltage a constant voltage using, for example, a Zener diode.
2 to the comparator circuit 82. If the reference voltage V1 and the detected voltage V2 have a predetermined relationship, the comparison circuit 82 determines that there is no fluctuation in the power supply voltage and does not cause the gate circuit 81 to generate a gate signal. Therefore, if the power supply voltage is normal, the gate circuit 81 does not generate a gate signal and keeps the triac 72 in a non-conductive state. Therefore, the terminal voltage V _C of the intermittent oscillation capacitor 6 reaches a predetermined charging voltage at every predetermined phase t1 of the AC power source e (solid line shown in FIG. 5A), as shown by the solid line in FIG. 5B. It acts in a direction to offset the power supply voltage, turns off the thyristor 52, and stops the oscillation operation. And power supply 1
When the polarity of is changed, it is charged to the opposite polarity, thereby causing it to oscillate intermittently at every predetermined phase of the power supply voltage e.

On the other hand, when the power supply voltage e fluctuates (for example, increases) as shown by the broken line in FIG. However, the reference voltage V1 is constant regardless of voltage fluctuations. Therefore, the comparison circuit 8
2 determines that the relationship between the reference voltage V1 and the detected voltage V2 is less than or equal to a predetermined ratio, and the gate circuit 81
Give a gate signal generation command signal to. In response, gate circuit 81 generates a gate signal to cause triac 72 to conduct. Therefore, the charging voltage V _C of the intermittent oscillation capacitor 6 is discharged through the discharge resistor 71 and the triax 72, and the terminal voltage of the intermittent oscillation capacitor 6 is substantially lowered, as shown by the broken line in FIG. 5B. . Therefore, by delaying the oscillation start timing of the high voltage circuit 4, the initial value of the tube current and the corresponding effective value of the tube current are lowered, and the tube current is kept in a steady state even when the power supply voltage increases. It works to maintain the current level, and can improve the fluctuation rate of the power supply voltage.

In addition, in the above description, a case was explained in which the charge in the intermittent oscillation capacitor 6 is controlled to be discharged only when the power supply voltage e increases. However, depending on the fluctuation state of the power supply voltage e, the discharge start phase may be controlled. That is, in the steady state of the power supply voltage e, as shown by the dashed line in FIG. If the power supply voltage rises, the gate signal is generated earlier and the discharge start phase is controlled to be earlier. If the power supply voltage drops, the gate signal generation is delayed and the discharge start phase is delayed. You can control it to do so.

FIG. 6 is a circuit diagram of another specific embodiment of the present invention. This embodiment was designed in consideration of the fact that the terminal voltage of the current limiting circuit 2 changes when the tube current i _T changes, and a secondary winding 85 is wound around the current limiting circuit 2. 85 is rectified by a rectifier circuit 83 and applied to the comparator circuit 82 as a detection voltage V2. The rest of the configuration is the same as that in FIG. 4, and since it can be easily understood from the explanation of the operation in FIG. 4, the explanation of the operation will be omitted.

FIG. 7 is an electric circuit diagram of another specific embodiment of the present invention. In this embodiment, in order to detect the tube current i _T , the primary winding of a transformer 86 is inserted between the power supply side end of the filament 32 and one end of the AC power supply 1, and the secondary winding of the transformer 86 is The tube current i _T is detected by the voltage induced in the line, and the rectifier circuit 83 supplies the DC voltage V2 correlated with the tube current change to the comparator circuit 82 as a detection voltage. The rest of the configuration is almost the same as the case shown in FIG. 4 described above, so a description of its operation will be omitted.

According to the embodiments shown in FIG. 4, FIG. 6, and FIG. 7 described above, the charge in the intermittent oscillation capacitor 6 is discharged at an appropriate timing based on the fluctuation factor of the tube current i _T. The phase of high-frequency, high-voltage oscillation operation can be varied in correlation to fluctuation factors.
It has the advantage of improving volatility. In addition, since the fluctuation rate of the input current can be improved, there is no need to consider the fluctuation of the input current as a current limiting choke, which allows the current limiting choke to be further miniaturized and prevents the temperature rise of the current limiting choke. There are advantages that can be achieved. Furthermore, if the lighting system is started every cycle as shown in Fig. 1, which is the background of this invention, when the power supply voltage increases, the turn-off phase of the thyristor fluctuates and commutation failure is likely to occur, causing flickering of the discharge lamp. However, in each of the above-described embodiments, the rate of fluctuation caused by fluctuations in the power supply voltage can be improved, so there is an advantage that flickering lighting of the discharge lamp can be prevented even if the power supply voltage fluctuates.

As described above, according to the present invention, it is possible to obtain a discharge lamp lighting device that can improve the fluctuation rate caused by fluctuation factors in the tube current and can also reduce the current limiting choke to an ultra-small size.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a discharge lamp lighting device of an every-cycle start lighting method, which is the background of the present invention. FIG. 2 is a waveform diagram of each part in FIG. 1. FIG. 3 is a circuit diagram of a discharge lamp lighting device expressing the principle of the present invention. FIG. 4 is a specific circuit diagram of an embodiment of the present invention. FIG. 5 is a waveform diagram of each part of FIG. 4. FIGS. 6 and 7 are circuit diagrams showing other practical examples of the present invention. In the figure, 1 is an AC power supply, 2 is a current-limiting choke, 3 is a discharge lamp, 4 is an intermittent high-frequency voltage generation circuit (high voltage circuit), 5 is a booster circuit, 51 is an oscillation capacitor, 52 is a thyristor, 53 is a booster inductor, 6 is a capacitor for intermittent oscillation, 7 is a discharge circuit, 7
1 is a discharge resistor, 72 is a switching element with a control electrode (TRIAT), 8 is a control means, 81 is a gate circuit, 82 is a comparison circuit, 83 is a rectifier circuit, 84
and 86 is a transformer, and 85 is a secondary winding of the current limiter yoke 2.

Claims (1)

[Scope of Claims] 1. An AC power source, a current limiting device including a current limiting choke, a discharge lamp connected to the AC power source via the current limiting choke, and a discharge lamp connected in parallel to the discharge lamp and controlling the voltage of the AC power source. In a discharge lamp lighting device comprising a high frequency high voltage generating means for re-igniting the discharge lamp by intermittently generating a high frequency high voltage every half cycle, the high frequency high voltage generating means comprises an oscillating capacitor and the oscillating capacitor. It consists of a series circuit of a thyristor and a boost inductor connected in parallel to a capacitor, and an intermittent oscillation capacitor connected in series with at least the series circuit of the thyristor and boost inductor, the capacitor being connected in parallel to the intermittent oscillation capacitor. and a discharge circuit consisting of a series circuit of an impedance element and a switching element with a control electrode, which discharges the charge of the intermittent oscillation capacitor; A discharge lamp lighting device further comprising a control means for controlling discharge operation timing.