JPS596480B2 - Dimmer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a first closed circuit is formed by an AC power source with a voltage approximately equal to or slightly lower than the rated voltage of the discharge lamp, an inductance, a capacitor, and a discharge lamp, and a first closed circuit is formed between the AC power source and the inductance. A second closed circuit is formed by the auxiliary capacitor and the switching element or the AC power source, the capacitor, the auxiliary inductance, and the switching element, and the inductance and the capacitor form a phase advance type current limiting element, and the AC power source of the switching element is The present invention relates to a light control device characterized in that the phase of the period during which the light is closed in each half cycle of the light is controlled.

It is an object of the present invention to improve luminous efficiency by eliminating pause periods in the lamp current, and to prevent shortened lamp life, increased noise, flickering, etc. due to dimming.

Figure 1 shows the basic circuit used as a conventional general discharge lamp dimming device, where VAc is an AC power supply, Li is an inductance, L is a discharge lamp, and s is a switching element. The light is controlled by the phase control.

In this case, since the phase of the main circuit is controlled by the switching element s during dimming, a pause period occurs in the lamp current ILA, and as a result, as vibration increases due to the iron core of the inductance Li, etc. It has a negative impact as noise. In addition, flickering is likely to occur during the ILA rest period, and there is a risk that the circuit design width must be narrowed in order to operate stably down to low temperatures.Furthermore, since the LA is not continuous, The effect is significant, shortening the lifespan, and in order to maintain stable lighting during dimming, it is necessary to apply a high voltage to the discharge lamp LA each cycle, which shortens the lifespan of the discharge lamp LA. , which had the disadvantage of causing noise interference. Figure 2 shows a conventional example of a dimming device that lights a discharge lamp with a power supply voltage that is approximately equal to or slightly lower than the rated voltage of the discharge lamp, where VAc is an AC power supply, Li is an inductance, Cl is a capacitor, LA is a discharge lamp, s is a switching element that closes and opens once during each half cycle of VAc, and in FIG. 1, a triac is used.

FIG. 3 shows operational waveforms of the main parts of FIG. 2, and the operation of FIG. 2 will be briefly explained with reference to FIG. 'After inserting Ic,
Considering a state in which L^ is started by some method and transitions to steady lighting, the circuit has a phase-advanced configuration, so a phase-advanced input current as shown in FIG. 3B flows.

Now, suppose that the switching element s is turned on at time to in FIG. By forming a pure LC oscillation system with S) in the closed state, the vibration becomes intensified and becomes an oscillating current as shown in the shaded area in FIG. 2B, which flows through S).

This enhanced oscillatory current, as shown by the shaded area, causes the voltage on C1 to rise to a peak voltage value that is higher than the peak voltage value that would have been reached if S had not closed during that VAc half cycle. At t1, when the current flowing through S is about to reverse, S turns off, but at this time, VCl has reached its peak value due to the strong vibration when S is turned on, and it can be considered that VAc has increased equivalently. . After t1, this increased VCl and VAC are superimposed and the discharge lamp L
A is applied, LA maintains lighting, and after the next TO, LA performs steady lighting in the same operation as described above. Therefore, by storing energy in C1 when S is turned on and superimposing the stored energy on VAC and supplying it to the discharge lamp when S is turned off, the VAc of a general lighting device that does not use S etc. can be reduced. is 1.5 to 2 of the rated VLA
Whereas twice the value was required, the LA can be lit with a VAO that is almost equal to or slightly lower than the rated VLA, and L
This makes it possible to reduce the size and weight of l and Cl. However, in the conventional example shown in Fig. 2, since S is provided substantially in parallel with LA, no current flows through LA when S is on, and ILA passes through the current stop section as shown in Fig. 3C. The waveform will be as follows. For this reason, the lamp efficiency and luminous efficiency are lowered, and it becomes necessary to increase the input current by that amount, which tends to reduce the effect of reducing the capacity of LlCl described above. In addition, this ILA rest period tends to increase the LA restrike voltage, which may narrow the design range of the circuit in order to ensure stable operation even at low and high temperatures, for example. Furthermore, like the one in Fig. 1, flickering is likely to occur during the ILA pause period, and the input current 11 during dimming is likely to occur.
The dimming is almost the same as when the light is fully lit, and the amount of decrease in ILA due to dimming flows to the switching element S. For this reason, the power loss caused by L1 does not change much between full lighting and dimming, and the power saving effect of dimming, where the input power is reduced by the amount of LA power reduction during dimming, cannot be expected. It had a drawback. The present invention has been made in view of these points, and the present invention will be explained in detail below using Examples.

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The voltage is approximately equal to or slightly lower than the rated voltage of A.
This AC power supply, inductance L1, capacitor C, and discharge lamp LA form a first closed circuit, and AC power supply VAC, inductance L1, auxiliary capacitor C2, and switching element S form a second closed circuit. .

At this time, C1 forms a phase advance type ballast together with L1. That is, if we focus only on the first closed circuit in FIG. 4 and express the relationship between C1 and L1 vectorially, ILA and V
Cl or -1) VLl intersect at approximately 90 degrees, and the combination of Ll and Cl is set as follows.

Here, VtA and ItA almost match in phase. Also, to prevent flickering of the discharge lamp at low temperatures, 1 = 1ωC
1 (1.5 to 2.5) ωL1.

(However, ω is the angular velocity of the VAC.) Also, S is a switching element that opens and closes once in each half cycle of the VAC, similar to the one in FIG. 2, and FIG. 4 shows the case where a triax is used. Figure 5 shows the main waveforms in Figure 4 after the LA starts up in some way and transitions to steady lighting.
The operation shown in FIG. 4 will be explained with reference to the drawings.

The first closed circuit consisting of VAC, Ll, Cl, and LA is phase-advanced, and therefore the input current 11n is phase-advanced. now,
Assume that time TO'('s in FIG. 5 is turned on. In a certain half cycle of AC, its polarity is the polarity shown in FIG. 4. In that half cycle of VAC, C2 up to TO The polarity of C1 maintains the voltage charged to the polarity shown in the first half cycle of VAC.
Although ILA is flowing, as is clear from Figure 5C, ILA has not yet reached its peak value, so C1
The voltage is also as shown in the figure. When S is turned on at TO, a vibration system of VAC-L1-C2- (S in closed state) is formed, and at the same time C2 is applied to both ends of the series circuit of C1 and LA.
is connected. At this time, the direction of the voltage of Cl and C2 is
As shown in FIG. 4, the direction of the voltage on C2 is the direction that prevents the discharge of charges on C2. When the current in S is about to reverse, S is turned off, but at this time the direction of the voltage on C2 is of opposite polarity to that shown, preparing for the operation described above in the next VAC half cycle. Consider the amount of charge of C1 that should be released during this S-on period.

Assuming S was not turned on, VAC would try to join C1 with the polarity shown, whereas if S was turned on, VAC would be applied to C1 with the polarity shown.
C2 joins C1 with the polarity shown. When viewed from the C1 side, AC and VC2 during the period equivalent to turning on S have opposite polarities,
VC2 is in a direction that prevents the discharge of charge from C1, and therefore VCl at the S off time t1 remains in a higher state than when S was not turned on. Therefore, the energy increased at t1 increases the VCl near zero of ILA to provide the voltage necessary to re-ignite the discharge lamp LA in the next half cycle, and after t1 until the next TO. The increased energy and VAC can keep the lights on. Note that FIG. 5C shows ILA, and FIG. 5G shows VCl.
This shows the case where the power is not turned on. After the next TO, the above-mentioned operation is repeated and LA is kept lit steadily. FIG. 5C shows IL^ in FIG. 4, with a slight depression occurring during the S-on period TO-t1. This means that discharge of charge from C1 is prevented, and at this time, an oscillating current as shown in FIG. 5F flows through S. This ILA+IS is the input current 11n, which has an extremely smooth waveform as shown in FIG. 5B. In Fig. 5E, the voltage waveform of C2 is the fifth
It rests on a part of the VLA as shown in Figure D'Tr). In this case, only ILA flows through C1, and its value can be further reduced by improving the lamp efficiency and luminous efficiency, and the withstand voltage of C1 can be lowered by the rate of reduction, and the price can be reduced. FIG. 6 shows another embodiment of the present invention, in which the second closed circuit is composed of an AC power supply VAC, a capacitor C1, an auxiliary inductance L2, and a switching element S.
1 and C1 form a phase advance type ballast similar to the one in FIG.

FIG. 7 shows the main waveforms of the discharge lamp LA in FIG. 6 after it has been started and shifted to steady lighting. Now, if S is turned on at time TO in FIG. 7, AC-C1-L2 is connected in addition to the first closed circuit.
A second closed circuit consisting of -S is formed, but this closed circuit is LC oscillatory, and a current such as Is in FIG. 7E flows through S.

At this time, the charge of C1 is increased by the oscillatory charging current 1S when the S is turned on, and after the S is turned off at t1, this increased energy of C1 and VAC are superimposed, and the next T
Keep the light on until O. After TO of the next VAO half cycle, the above-mentioned operation is repeated and LA is kept lit steadily. VAC-C1- even during the ON period of S and VAC-C1-
A continuous current flows through the first closed circuit of L1-LA.
becomes an extremely smooth waveform as shown in Figure 7C, and Iin
In the waveform shown in FIG. 7B, in which Is in FIG. 7C and FIG. 7E are superimposed, the shaded portion of Bf)Iin in FIG. 7 is the oscillatory charging current of C1 when S is turned on. Therefore, steady lighting of the discharge lamp LA can be maintained using an AC power supply with a voltage that is approximately equal to or slightly lower than the rated voltage of the discharge lamp LA, so Ll
, Cl can be small, and since only the current of the discharge lamp LA flows through the inductance, the power can be sufficiently reduced. FIG. 8 shows the circuit shown in FIG. 6 with an added control section for the switching element S, in which the ON phase of S is controlled by a variable resistor RO to control the light.

SO is a trigger element, and CO is a capacitor. As described above, dimming can be achieved by phase control using the switching element S, but the lamp current becomes L continuously, eliminating the pause period, improving the lamp coverage rate and luminous efficiency, and achieving the rated value with a small input current. Since the lamp power and rated light output can be maintained, circuit design is easier, and short lamp life, flickering during dimming, and increased noise can be eliminated.

As described above, the present invention forms a first closed circuit with an AC power supply having a voltage approximately equal to or slightly lower than the rated voltage of the discharge lamp, an inductance, a capacitor, and the discharge lamp, and a first closed circuit is formed between the AC power supply, the inductance, and the auxiliary capacitor. A second closed circuit is formed by the switching element or the AC power supply, the cofundacer, the auxiliary inductance, and the switching element, and the inductance and the capacitor form a phase advance type current limiting element, and each of the AC power supplies of the switching element Since the half-cycle closing period is made like a phase-closing structure, the lamp current is continuous and there is no rest period, improving the lamp efficiency and luminous efficiency, and achieving the rated lamp power and rated power with a small input current. In addition to providing light output, it also prevents short lamp life, flickering during dimming, and increased noise, and dimming reduces power loss due to inductance, which is said to have a significant power saving effect. It is effective.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an example of a conventional light control device, Figure 2 is a circuit diagram of another example of the same as above, Figures 3A-D are voltage and current waveform diagrams of main parts of the same as above, and Figure 4 is the invention of the present invention. Circuit diagram of one embodiment of FIG. 5A
6 is a circuit diagram of another embodiment of the present invention, FIGS. 7A to 7E are voltage and current waveform diagrams of main parts of the same as above, and FIG. 8 is a diagram of the same as above. It is a circuit diagram. VAC... AC power supply, L1... Inductance, C1... Capacitor, LA...
...Discharge lamp, L2...Auxiliary inductance, C
2... Auxiliary capacitor, S... Switching element.

Claims (1)

[Claims] 1. A first closed circuit is formed by an AC power source with a voltage approximately equal to or slightly lower than the rated voltage of the discharge lamp, a series circuit of an inductive reactance and a capacitive reactance, and the discharge lamp, and the AC power source and the alternating current of the series circuit are formed. reactance on the power supply side,
A second closed circuit is formed by the auxiliary reactance and the switching element, and the series circuit forms a phase advance type current limiting element, and the auxiliary reactance is formed by a reactance of the same type as the reactance on the discharge lamp side of the series circuit. A light control device, characterized in that the period during which the switching element is closed in each half cycle of the AC power source is controlled in phase.