JPH10284272A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high power factor type device applicable to a high- voltage type by comprising a discharge lamp and a lighting circuit including a serial ballast inductor in the discharge lamp and connecting an auxiliary inductor to any of the lighting circuit and the discharge lamp in parallel. SOLUTION: When the other switching element 42 is turned on, a smoothing capacitor voltage is applied to an auxiliary inductor 70 via a vibration capacitor 81, and electromagnetic energy is accumulated. Thereafter, the energy, migrates to a commercial power supply 10 power supply period during which a potential VC variation curve and a power voltage waveform are crossing, however, at the point the auxiliary inductor 70 still exhibits inertial action and maintains a right-direction current; therefore, a current of a commercial power supply 10 increases, and supply power increases. If a momentary value of the voltage of a commercial power supply 10 does not meet a tube voltage of a discharge lamp 91, it is possible to promote power supply from an AC power supply 10 by inertial action. For the sake of the auxiliary inductor 70, an impedance of an inverter load circuit including an illuminating circuit 90 and the auxiliary inductor 70 is lowered, and supply power via the inverter circuit increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a full-wave rectifier circuit for rectifying a commercial power supply voltage, a smoothing capacitor connected to a DC output terminal of the full-wave rectifier circuit, and a DC voltage of the smoothing capacitor. The present invention relates to a discharge lamp lighting device including an inverter for converting into a high-frequency AC.

[0002]

2. Description of the Related Art A conventional apparatus shown in FIG. FIG.
The device has a commercial power supply 10. A full-wave rectifier circuit 20 for rectifying the voltage of the commercial power supply 10 is provided. The smoothing capacitor 30 is connected to the DC output terminal of the full-wave rectifier circuit 20.
A pair of switching elements 41 and 42 are connected to both ends of the smoothing capacitor 30 in series and controlled to be turned on and off alternately. Flywheel diodes 51.5 connected in anti-parallel with each of switching elements 41 and 42
2 is provided. A lighting circuit 90 including a discharge lamp 91 and a ballast inductor 92 in series with the discharge lamp 91 is provided. A vibration capacitor 81 is connected in parallel to one switching element 41 via a lighting circuit 90. Lighting circuit 90
And a vibration capacitor 82 connected in parallel to the other switching element 42 via Vibration capacitor 8
1 is connected in parallel with one rectifying diode 21 belonging to the full-wave rectifier circuit 20. The vibration capacitor 82 is connected in parallel with another rectifier diode 22 belonging to the full-wave rectifier circuit 20. The vibration capacitor 82 can be omitted. The capacitance of the vibration capacitors 81 and 82 is appropriately small, and the potential VC at the connection point fluctuates. Its fluctuating potential V
When the value of C reaches a value corresponding to the voltage of the AC power supply 10, the AC power supply 10 conducts. For this reason, the conduction angle of the AC power supply 10 is wide and the power factor is high.

[0003]

In the apparatus shown in FIG. 4, when the fluctuating potential VC reaches a value corresponding to the voltage of the AC power supply 10, the AC power supply 10 is turned on. However, when the lighting circuit 90 corresponding to the inverter load has a high impedance, the power supply from the AC power supply 10 becomes insignificant, and the power of the discharge lamp 91 cannot be maintained at the rated value. Therefore, it is not suitable for a high-power discharge lamp lighting device for the discharge lamp 91 having a large rated power consumption. An object of the present invention is to provide a high power factor type discharge lamp lighting device applicable to a high power type.

[0004]

The device of the present invention includes a commercial power supply. A full-wave rectifier circuit for rectifying a commercial power supply voltage is provided. A smoothing capacitor connected to a DC output terminal of the full-wave rectifier circuit; A smoothing capacitor includes a pair of switching elements which are connected in series in both ends and which are controlled to be turned on and off alternately. A flywheel diode is connected in anti-parallel with each switching element. A lighting circuit including a discharge lamp and a ballast inductor in series with the discharge lamp is provided. A vibration capacitor is connected in parallel to one of the switching elements via a lighting circuit. An oscillating capacitor is connected in parallel with one rectifying diode belonging to the full-wave rectifier circuit. Further, an auxiliary inductor is provided. Connect the auxiliary inductor in parallel with either the lighting circuit or the discharge lamp. This is a feature of the present invention. The role of the auxiliary inductor is to maintain the AC power supply at a high power factor,
The purpose is to increase the power consumption of the discharge lamp. Its effect is described as a low impedance action or inertia action by the auxiliary inductor.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The discharge lamp lighting device of FIG. A full-wave rectifier circuit 20 for rectifying a commercial power supply 10 voltage is provided. The smoothing capacitor 30 is connected to the DC output terminal of the full-wave rectifier circuit 20. A pair of switching elements 41 and 42 are connected to both ends of the smoothing capacitor 30 in series and controlled to be turned on and off alternately. It has flywheel diodes 51 and 52 connected in anti-parallel with the respective switching elements 41 and 42. A discharge lamp 91 and a ballast inductor 9 in series with the discharge lamp 91
2 is provided. A vibration capacitor 81 is connected in parallel to one of the switching elements 41 via a lighting circuit 90. The vibration capacitor 81 is connected to one rectifier diode 21 belonging to the full-wave rectifier circuit 20.
And connected in parallel. The above configuration is common to the conventional FIG. 4 apparatus. 1 includes an auxiliary inductor 70.
The auxiliary inductor 70 is connected in parallel with the lighting circuit 90.
This is a feature of the present invention. Auxiliary inductor 70
Plays a role in maintaining the AC power supply 10 at a high power factor and
1 is to increase power consumption. The effect is described as a low impedance action or an inertia action by the auxiliary inductor 70. FIG. 1 is supplemented. Full-wave rectifier circuit 20 is composed of rectifier diodes 21, 22, 23,
24 is assembled into a bridge. 1 includes a vibration capacitor 82 connected in parallel to the other switching element 42 via a lighting circuit 90. The vibration capacitor 82 is connected in parallel with another rectifier diode 22 belonging to the full-wave rectifier circuit 20. Vibration capacitor 82
Can be omitted. The same effect is obtained even if the vibration capacitor 81 is omitted while the vibration capacitor 82 is left. VC is a potential between the vibration capacitors 81 and 82. When the vibration capacitor 82 is omitted, the potential at the connection point between the vibration capacitor 81 and the lighting circuit 90 becomes VC. Discharge lamp 91
Is a fluorescent lamp. Reference numeral 93 denotes a preheating capacitor connected between the non-power-supply-side terminals of the fluorescent lamp 91. 1 will be described with reference to FIG. The capacitance of the vibration capacitors 81 and 82 is appropriately small, and the voltage fluctuates. The capacity of the smoothing capacitor 30 is large and its voltage V
E hardly changes. Vibration capacitors 81 and 82
Appears as a change in the potential VC. The operation during the ON period of the other switching element 42 will be considered. When the switching element 42 is turned on, a current flows through the circuit including the lighting circuit 90 and the switching element 42.
With this, the potential VC sinks. Assuming that the voltage of the AC power supply 10 is a positive half wave having a rightward polarity, the voltage V1 can be represented as shown in FIG. The power supply voltage V1 in FIG. 2 is a potential at a potential VC when it is assumed that the rectifying diode 24 corresponding to the polarity is conductive or conductive. Although the potential VC drops as described above, when it intersects with the power supply voltage V1,
It is clipped to the power supply voltage V1 and further settling is prevented. At this time, the AC power supply 10 conducts. The phase a in FIG. 2 is a power supply suspension period of the AC power supply 10, and the phase b is a power supply period (more precisely, an intermittent power supply period corresponding to a high-frequency potential VC cycle). Vibration capacitors 81 and 82
(More precisely, the sum of the capacitances of 81 and 82) is appropriately reduced and the potential VC fluctuation is strengthened, and the potential VC fluctuation curve sweeps the entire waveform of the smoothing capacitor voltage VE. b. Therefore, the power factor of AC power supply 10 is higher than in the case of FIG. The current of the AC power supply 10 contains a high-frequency component, but if a suitable filter circuit (for example, a smoothing inductor (not shown) in series with the AC power supply 10) is provided, a smooth low-frequency AC waveform is obtained. Here, the role of the auxiliary inductor 70 will be described. When the other switching block 42 is turned on, the voltage VE of the smoothing capacitor 30 is applied to the auxiliary inductor 70 via the vibration capacitor 81. A rightward current is formed in the auxiliary inductor 70 and stores electromagnetic energy therein. Thereafter, the process proceeds to the AC power supply 10 power supply period b in which the potential VC fluctuation curve and the power supply voltage V1 waveform intersect. At that time, the auxiliary inductor 70 exhibits an inertial effect and still attempts to maintain the rightward current. Due to the inertial action of the auxiliary inductor 70, the current of the AC power supply 10 increases, and the power supplied thereto increases. Incidentally, even when the instantaneous value of the power supply voltage of the AC power supply 10 is less than the tube voltage of the discharge lamp 91, the power supply from the AC power supply 10 can be promoted because of the above-described inertial action. . On the other hand, since the auxiliary inductor 70 is provided, the impedance of the entire circuit (the inverter load circuit) including the lighting circuit 90 and the auxiliary inductor 70 is reduced. For this reason, the current of the AC power supply 10 generated via the inverter load circuit increases, and the power supplied thereto increases. The power supplied from the AC power supply 10 matches the power consumption of the discharge lamp 91 ignoring the circuit loss. Therefore, the power consumption of the discharge lamp 91 can be set higher. Another embodiment of the present invention will be described with reference to FIG. The difference from FIG. 1 is that the auxiliary inductor 70 is connected to the lighting circuit 90 or the discharge lamp 91 in parallel. In FIG. 3, the auxiliary inductor 70 is connected in parallel with the discharge lamp 91, but the effect is almost the same. In the case of FIG. 3 as well, since the auxiliary inductor 70 is provided, the impedance of the inverter load is reduced, and the power supply from the AC power supply 10 is increased. In addition, a current flows through the auxiliary inductor 70 via the ballast inductor 92, and electromagnetic energy is accumulated in the auxiliary inductor 70. Therefore, an inertia effect of the auxiliary inductor 70 substantially similar to that of FIG. 1 acts, and the power supply from the AC power supply 10 is increased.

[0006]

The present invention utilizes an auxiliary inductor connected in parallel with either a lighting circuit or a discharge lamp. According to this, a high power factor type discharge lamp lighting device applicable to a high power type can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a discharge lamp lighting device according to the present invention.

FIG. 2 is a waveform chart for explaining the operation.

FIG. 3 is a circuit diagram showing another discharge lamp lighting device according to the present invention.

FIG. 4 is a circuit diagram showing a conventional discharge lamp lighting device.

[Explanation of symbols]

10: commercial power supply, 20: full-wave rectifier circuit, 21: rectifier diode, 22: rectifier diode, 23: rectifier diode, 24: rectifier diode, 30: smoothing capacitor, 41: switching element, 42: switching Element, 51: flywheel diode, 52: flywheel diode, 70: auxiliary inductor, 81: oscillation capacitor, 82: oscillation capacitor, 90: lighting circuit, 91: discharge lamp, 92: ballast inductor, 93:
Preheating capacitor

Claims (1)

[Claims] 1. A commercial power supply (10), comprising a full-wave rectifier circuit (20) for rectifying a voltage of the commercial power supply (10);
A smoothing capacitor (30) connected to a DC output terminal of the full-wave rectifier circuit (20); a pair connected in series with both ends of the smoothing capacitor (30) and controlled to alternately turn on and off; And a flywheel diode (51, 52) connected in anti-parallel with each of the switching elements (41, 42), and a discharge lamp (91) and the discharge lamp (91). And a lighting circuit (90) including a ballast inductor (92) in series with the vibration capacitor (81) connected in parallel to one of the switching elements (41) via the lighting circuit (90).
The vibration capacitor (81) is connected to the full-wave rectifier circuit (2).
A discharge lamp lighting device connected in parallel with one rectifying diode (21) belonging to (0), comprising an auxiliary inductor (70),
0) is connected in parallel with either the lighting circuit (90) or the discharge lamp (91).