JP2008177110A - Dimming ballast - Google Patents

Abstract

The present invention provides a dimming ballast capable of long life, low noise and precise dimming control.
The dimming ballast is a copper iron type dimming ballast having a leakage transformer T for supplying an AC voltage to the discharge lamps FLR1, FLR2 and a first capacitor C0. Furthermore, the dimming ballast can selectively disconnect the second capacitors C1 and C2 connected in parallel with the first capacitor C0 and the connection between the first capacitor C0 and the second capacitors C1 and C2. And an energy saving unit 2 which is a simple control means.
[Selection] Figure 1

Description

  The present invention relates to a copper iron type dimming ballast for stably lighting a discharge lamp such as a fluorescent lamp and controlling dimming.

  In recent years, there has been a growing demand for power saving from the viewpoints of laws and regulations and global environmental conservation. Among them, lighting equipment has become a major theme for power saving because of its immediate effect. Conventionally, lighting power saving methods in offices and factories include (A) providing individual lighting fixtures with switches and manually turning them off, (B) reducing illuminance at night when there are no people, (C) electronics There is a method of performing dimming control by an electronic ballast composed of parts. Of these methods, the method of manually turning off (A) has a problem that only a limited number of lights can be turned off with one switch, and the power saving effect is small. Further, in the method (B) of reducing the illuminance at night, there is a problem that the dimming control is rough by the on / off control of all light or half light.

  On the other hand, the electronic ballast in (C) uses the output of the PWM-controlled DC chopper circuit as the power source of the full-bridge type switching circuit, connects the discharge lamp as the load of the full-bridge type switching circuit, and sets the current direction of the discharge lamp to several By switching at a low frequency cycle within 100 Hz, high-efficiency and stable control of the dimming range is realized (for example, see Patent Document 1).

JP 2004-127874 A

  As described above, the electronic ballast is excellent in terms of efficiency and dimming range. However, since the electronic ballast is composed of a large number of electronic components, the lifetime is, for example, 8 compared to the legal service life of 15 years. There was the problem of being as short as a year. Further, since the switching power supply is used, there is a possibility that a failure due to noise occurs.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a dimming ballast capable of performing long dimming control with long life and low noise.

The present invention provides a coil for supplying an AC voltage to a discharge lamp, a first capacitor inserted in series between the discharge lamp and the coil, and a plurality of second capacitors connected in parallel to the first capacitor. And a control means capable of selectively disconnecting the connection between the first capacitor and the plurality of second capacitors.
In one configuration example of the dimming ballast of the present invention, the capacitance value of the first capacitor is set to a value that can realize a predetermined maximum dimming state.

The present invention also provides a coil for supplying an AC voltage to the discharge lamp, a first impedance element inserted in series between the discharge lamp and the coil, the first impedance element, and the discharge lamp. And a plurality of second impedance elements inserted in series between the two and a control means capable of selectively short-circuiting the plurality of second impedance elements.
In one configuration example of the dimming ballast of the present invention, the sum impedance of the first impedance element and the plurality of second impedance elements is set to a value that can realize a predetermined maximum dimming state. It is what is done.

  According to the present invention, by using a copper-iron type dimming ballast, the life of the dimming ballast can be extended as compared with an electronic ballast. Further, in the present invention, by adding the second capacitor (or second impedance element) for dimming and the control means, the dimming control that is two steps in the conventional copper-iron type ballast is performed. It can be more precise than the stage. In addition, the use of a copper-iron dimming ballast can reduce the possibility of high-frequency interference as compared with an electronic ballast.

  In the present invention, the capacitance value of the first capacitor is set to a value capable of realizing the maximum dimming state, or the total impedance of the first impedance element and the plurality of second impedance elements is adjusted to the maximum. By setting the light state to a realizable value, it is possible to satisfy the minimum condition that can stably maintain the discharge of the discharge lamp, so that the discharge lamp can be prevented from extinguishing, and the control means Even in the case of failure, the lighting state of the discharge lamp can be ensured.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a dimming ballast according to the first embodiment of the present invention. The dimming ballast is composed of a dimming ballast main body 1 and an energy saving unit 2 which is a control means. The dimming ballast body 1 includes a leakage transformer T and capacitors C0, C1, and C2. The energy saving unit 2 includes relays RL1 and RL2. In FIG. 1, FLR1 and FLR2 are discharge lamps such as fluorescent lamps, and C3 and C4 are noise prevention capacitors. The dimming ballast main body 1 and the energy saving unit 2 may be integrated.

  The AC power supply voltage Vin is supplied to the primary winding P1 of the leakage transformer T. When the AC power supply voltage Vin is applied, the electrodes of the discharge lamps FLR1 and FLR2 are preheated by the electrode preheating winding P2 of the leakage transformer T, and at the same time, the capacitor C0 (or the secondary winding P3 of the leakage transformer T). Since the voltage is applied to the discharge lamps FLR1 and FLR2 through the capacitors C0 and C1, the capacitors C0 and C2, and any combination of the capacitors C0, C1 and C2, the discharge lamps FLR1 and FLR2 are turned on.

  In such lighting of the discharge lamps FLR1 and FLR2, in order to reduce the power consumption of the discharge lamps FLR1 and FLR2, the current flowing through the discharge lamps FLR1 and FLR2 may be reduced. Therefore, the energy saving unit 2 of the present embodiment realizes dimming control by changing the number of capacitors (capacitor impedance) inserted between the leakage transformer T and the discharge lamps FLR1 and FLR2. In the present embodiment, the capacitance value of the capacitor C2 is made larger than the capacitance value of the capacitor C1.

  In order to turn on the discharge lamps FLR1 and FLR2, the dimming control terminals DC1 and DC2 of the energy saving unit 2 are opened (OFF). In this case, since no current flows through the coils of the relays RL1 and RL2, the contacts CT1 and CT2 of the relays RL1 and RL2 remain closed. As a result, parallel-connected capacitors C0, C1, and C2 are inserted between the leakage transformer T and the discharge lamps FLR1 and FLR2.

  In order to change the discharge lamps FLR1 and FLR2 from the all-light lighting state to the dimming state (for example, 78% lighting), the dimming control terminal DC1 is connected to the power supply terminal DCC (ON), and the dimming control terminal DC2 is opened. Put it in a state. In this case, since a current flows from the power supply terminal DCC to the coil of the relay RL1, the contact CT1 of the relay RL1 is opened. On the other hand, the contact CT2 of the relay RL2 is kept closed. As a result, parallel-connected capacitors C0 and C2 are inserted between the leakage transformer T and the discharge lamps FLR1 and FLR2, and the impedance of the capacitor is higher than that in the all-light lighting state. The flowing current decreases, and the discharge lamps FLR1 and FLR2 are dimmed.

  In order to make the discharge lamps FLR1 and FLR2 further dimmed (for example, 64% lighting), the dimming control terminal DC2 is connected to the power supply terminal DCC, and the dimming control terminal DC1 is opened. In this case, the contact CT2 of the relay RL2 is opened. On the other hand, the contact CT1 of the relay RL1 is kept closed. As a result, parallel-connected capacitors C0 and C1 are inserted between the leakage transformer T and the discharge lamps FLR1 and FLR2, and the impedance of the capacitor is further increased compared to the case of 78% lighting. The current flowing through FLR2 further decreases, and the illuminance of discharge lamps FLR1 and FLR2 decreases.

  Further, in order to place the discharge lamps FLR1 and FLR2 in a half-light state (50% lighting), the dimming control terminals DC1 and DC2 are connected to the power supply terminal DCC. Thereby, contacts CT1 and CT2 of relays RL1 and RL2 are opened, and capacitor C0 is inserted between leakage transformer T and discharge lamps FLR1 and FLR2. As a result, the impedance of the capacitor is maximized and the current flowing through the discharge lamps FLR1, FLR2 is minimized. The capacitor C0 is an element for maintaining the minimum conditions when dimming the discharge lamps FLR1 and FLR2. The dimming state of 50% or less for general lighting gives humans a dark feeling visually, is not suitable for lighting, and 50% dimming is the maximum dimming from the viewpoint of stable discharge. .

  This embodiment is a so-called copper iron type dimming ballast. A copper-iron type dimming ballast is generally composed of a leakage transformer T and a first capacitor C0. On the other hand, in the present embodiment, second dimming capacitors C1 and C2 are added to realize four-step dimming control. For example, if three dimming capacitors are used, eight levels of dimming control can be performed, and if four dimming capacitors are used, sixteen levels of dimming control can be performed. Considering the permissible range inherent in the luminance discharge lamp, control that is too precise does not make much sense. Therefore, in this embodiment, there are two dimming capacitors.

  Thus, in this embodiment, by using a copper-iron type dimming ballast, the number of electronic components can be significantly reduced compared to an electronic ballast, and the life of the dimming ballast can be reduced, for example. It can be as long as 20 years. Furthermore, in the present embodiment, by adding a dimming capacitor and an energy saving unit as a control means, the dimming control, which is two steps in the conventional copper-iron type ballast, is more precisely divided into four or more steps. can do. In addition, the copper-iron type ballast does not perform high-frequency switching like an electronic ballast, and the current waveform is better than that of an electronic ballast, reducing the possibility of high-frequency interference. .

  In the present embodiment, the capacitance value of the first capacitor C0 is set to a value that can realize a predetermined maximum dimming state. By leaving the capacitor C0 fixed at the time of maximum dimming, the discharge lamps FLR1 and FLR2 can satisfy the minimum condition for stably maintaining the discharge, so that the discharge lamps FLR1 and FLR2 do not disappear. In addition, even when the control means fails, it is possible to ensure the lighting state of the discharge lamps FLR1 and FLR2.

  The energy-saving unit 2 may be operated manually, but in combination with a sensor that detects the presence of a person, the control terminals DC1 and DC2 of the energy-saving unit 2 are controlled by signals from the sensor, and dimming control is automatically performed. You may make it carry out.

Moreover, in this Embodiment, although relay RL1 and RL2 were used as a contact in a control means (energy saving unit 2), you may use an electronic non-contact element.
In the present embodiment, a leakage transformer is used as a coil for supplying an AC voltage to the discharge lamps FLR1 and FLR2. However, the present invention is not limited to this. The separated type may be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 2 is a circuit diagram showing a configuration of a dimming ballast according to the second embodiment of the present invention. In FIG. 2, the energy saving unit 2 and the electrode preheating winding P2 of the leakage transformer T are omitted in order to simplify the description. In the first embodiment, the capacitors C0, C1, and C2 are used as elements for controlling the current flowing through the discharge lamps FLR1 and FLR2. Is used.

  When impedance elements such as resistors and coils are used, a plurality of impedance elements R0, R1, R2 are inserted in series between the discharge lamp FLR and the leakage transformer T as shown in FIG. The control method of the contacts CT1 and CT2 by the control means (not shown) is opposite to that of the first embodiment. The contacts CT1 and CT2 are in the maximum dimming state when the contacts CT1 and CT2 are closed, and all the lights are displayed when the contacts CT1 and CT2 are opened. Lights up. In the present embodiment, the sum of the impedance of the first impedance element R0 and the second impedance elements R1 and R2 satisfies the minimum condition that can stably maintain the discharge of the discharge lamp FLR. Thus, also in this embodiment, the same effect as that of the first embodiment can be obtained.

  The present invention can be applied to dimming control of a discharge lamp such as a fluorescent lamp.

It is a circuit diagram which shows the structure of the dimming ballast which concerns on the 1st Embodiment of this invention. It is a circuit diagram which shows the structure of the dimming ballast which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dimming ballast body, 2 ... Energy-saving unit, T ... Leakage transformer, C0, C1, C2, C3, C4 ... Capacitor, RL1, RL2 ... Relay, FLR1, FLR2 ... Discharge lamp.

Claims (4)

A coil for supplying an alternating voltage to the discharge lamp;
A first capacitor inserted in series between the discharge lamp and the coil;
A plurality of second capacitors connected in parallel with the first capacitor;
A dimming ballast comprising control means capable of selectively disconnecting the connection between the first capacitor and the plurality of second capacitors. The dimming ballast according to claim 1,
The dimming ballast characterized in that the capacitance value of the first capacitor is set to a value capable of realizing a predetermined maximum dimming state. A coil for supplying an alternating voltage to the discharge lamp;
A first impedance element inserted in series between the discharge lamp and the coil;
A plurality of second impedance elements inserted in series between the first impedance element and the discharge lamp;
A dimming ballast comprising control means capable of selectively short-circuiting the plurality of second impedance elements. The dimming ballast according to claim 3, wherein
The dimming ballast, wherein the sum impedance of the first impedance element and the plurality of second impedance elements is set to a value that can realize a predetermined maximum dimming state.

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