JPH0521187A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To make the starting, the dimming, and the ON/OFF control of a discharge lamp easier, and to protect its service life. CONSTITUTION:In a discharge lamp lighting device provided with a rectifier 2 connected to an AC power source 1, an inverter 4 connected to the rectifier 2, and a discharge lamp 5 connected to the inverter 4, an active filter circuit 7 is provided between the rectifier 4 and the active filter circuit 7, and a feedback circuit 8 is provided between the inverter 4 and the active filter circuit 7. Consequently, the output voltage of the active filter circuit 7 can be made variable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device.

[0002]

2 and 3 show a conventional example of a discharge lamp lighting device. In FIG. 2, an AC power supply (input power supply) 1 is rectified by a rectifier 2, a voltage smoothed by a capacitor 3 is input to an inverter 4, and a discharge lamp 5 is turned on. In FIG. 3, the voltage is rectified similarly to FIG. 2 and the voltage partially smoothed by the partial smoothing circuit 6 is input to the inverter 4 to turn on the discharge lamp 5. The inverter 4 may be a push-pull type, a bridge type or the like.

[0003]

The above-mentioned prior art has not considered the following points. In the example of FIG. 2, since the waveform of the current extracted from the power source is a capacitor input type, it becomes a steep waveform and has a distorted waveform containing many harmonic components. Therefore, the power factor is poor, and it is considered that the power system is adversely affected. The example of FIG. 3 has less harmonic components of the input current of the power supply than the example of FIG. 2, but it cannot be said to be perfect. Further, in the prior art, the high voltage required for starting the discharge lamp is applied by boosting by the transformer in the inverter, boosting by LC resonance, etc., and a special means is required for starting. It was Further, in the case of dimming the discharge lamp, it was necessary to take measures such as via an impedance in series with the discharge lamp or changing the oscillation frequency of the inverter. Further, there is no circuit for compensating for fluctuations in the input power supply, and when the input power supply is high, the output is unnecessarily high, which may adversely affect the life of the parts used and the discharge lamp. The present invention has been made in view of the above points, and facilitates starting, dimming, and on / off of a discharge lamp,
It is an object of the present invention to provide a discharge lamp device capable of protecting its life.

[0004]

The above object is to provide an active filter circuit between a rectifier and an inverter and a feedback circuit between the inverter and the active filter circuit so as to reduce the output voltage of the active filter circuit. This is achieved by making it variable.

[0005]

Since the above means is provided, harmonic distortion of the input current can be eliminated and the output voltage of the active filter circuit can be changed.

[0006]

EXAMPLES Next, the present invention will be specifically described by way of examples. FIG. 1 shows an embodiment of the present invention. In addition,
Since the same parts as those in the past are designated by the same reference numerals, the description thereof will be omitted. In this embodiment, between the rectifier 2 and the inverter 4,
The active filter circuit 7 is provided, and the feedback circuit 8 is provided between the inverter 4 and the active filter circuit 7 to make the output voltage of the active filter circuit 7 variable. By doing so, the harmonic distortion of the input current can be eliminated, and the output voltage of the active filter circuit can be changed.
It is possible to obtain a discharge lamp lighting device that facilitates starting, dimming, turning on / off, and can protect the life. That is, the electric power enters the input current distortion countermeasure circuit (active filter circuit) 7 including a boost chopper from the input power source 1 through the rectifier 2. The active filter circuit 7 has a function of making the waveform of the input current extracted from the input power source 1 into a sinusoidal waveform without harmonic distortion. The inverter 4 is configured as a push-pull type or a bridge type, and the discharge lamp 5 may be various types such as a fluorescent lamp and a high pressure discharge lamp. The output voltage E becomes a certain DC voltage by the active filter circuit 7, but the voltage E can be controlled via the feedback circuit 8 depending on the state of the inverter 4. When the discharge lamp 5 is started, the higher the voltage E, the better the startability. It can be realized by lowering the voltage E during dimming of the discharge lamp 5. Further, the voltage E can be lowered and protected even at the end of the life of the discharge lamp 5. Further, by making the voltage E constant with respect to the fluctuation of the input power source 1, it is possible to extract a constant output light. In this way, various operations required by the inverter 4 are realized by changing the output voltage E of the active filter circuit 7. Therefore, it is sufficient for the inverter 4 to be a circuit that operates relatively easily, and the inverter 4
The reliability of itself is improved. As described above, according to the present embodiment, harmonic distortion of the input current of the discharge lamp lighting device is eliminated, and starting, dimming, and on / off necessary for lighting the discharge lamp are facilitated, and the life of the discharge lamp is protected. Can be done.

[0007]

As described above, according to the present invention, the starting of the discharge lamp,
It is possible to obtain a discharge lamp lighting device that facilitates dimming, on / off and life protection, facilitates starting, dimming, on / off of a discharge lamp, and enables life protection. it can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is an explanatory diagram of a conventional discharge lamp lighting device.

FIG. 3 is an explanatory diagram of another example of the conventional discharge lamp lighting device.

[Explanation of symbols]

1 ... AC power supply (input power supply) 2 ... Rectifier 4 ... Inverter 5 ... Discharge lamp 7 ... Active filter circuit 8 ... Feedback circuit

Claims (1)

Claim: What is claimed is: 1. A discharge lamp lighting device comprising: a rectifier connected to an AC power source; an inverter connected to the rectifier; and a discharge lamp connected to the inverter. A discharge lamp lighting device, wherein an active filter circuit is provided between the inverter and the inverter, and a feedback circuit is provided between the inverter and the active filter circuit so that an output voltage of the active filter circuit can be varied.