JP4370832B2 - Light control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light control device including a first phase control circuit including a self-extinguishing control element and a second phase control circuit including a thyristor.
[0002]
[Prior art]
A first phase control circuit provided with a self-extinguishing control element and a second phase control circuit provided with a thyristor are connected in parallel and interposed in series between an AC power source and a load so that an AC voltage half wave The self-extinguishing control element of the first phase control circuit is operated by tilt control at the desired phase of the first phase, and when the conduction is almost saturated, a trigger signal is supplied to the thyristor of the second phase control circuit. A light control device configured to perform the order phase control by arcing is known (see, for example, claim 5 of FIG. 1 and FIG. 12).
[0003]
According to Patent Document 1, since the tilt control is performed at the start of the rank phase control, the generation of acoustic noise from the load or the reactor inserted in series in the load circuit is suppressed, and the resistance is reduced after the tilt control. Since the load current flows mainly on the thyristor side when the relatively small thyristor is turned on, heat generation of the dimmer is reduced.
[0004]
[Patent Document 1]
JP-A-6-338395 [Problem to be Solved by the Invention]
In the prior art disclosed in Patent Document 1, in the case of a light load, since a trigger current sufficient for starting the thyristor does not flow, the thyristor may not be turned on. Is continued until the end of the AC voltage half-wave.
[0005]
However, in the above-described prior art, even if the polarity of the AC voltage is reversed and the next half-wave is reached, the thyristor may continue to be turned on. There is. In contrast, if a dummy resistor is connected in parallel with the load as is known, the thyristor can be reliably operated at light loads without supplying a trigger signal that continues until the end of the AC voltage half-wave as described above. Can be turned on. However, such a configuration has a problem that power loss increases and costs increase.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a light control device that prevents the occurrence of brightness flicker due to a failure in starting a thyristor at a light load.
[0007]
[Means for achieving the object]
A dimming device according to a first aspect of the present invention includes a first phase control circuit having a self-extinguishing control element that is inserted into an AC power supply line and controls the phase of the AC voltage; and inserted into the AC power supply line. A second phase control circuit having a thyristor for phase-controlling; a load current detecting means for detecting a load current arranged in series between the first and second phase control circuits and the load ; When the self-extinguishing control element of the first phase control circuit is operated by tilt control at the desired phase of the voltage half-wave, and when the conduction is almost saturated, the thyristor of the second phase control circuit In addition to supplying a trigger signal, the load size is obtained based on the detection data of the load current detecting means. When the load size is equal to or smaller than a predetermined value, the trigger signal is sent to the thyristor of the second phase control circuit. Don't supply It is characterized in that it comprises a; and configured the control means so that I line phase control only by the first phase control circuit.
[0008]
Definition and technical meaning of Oite the present invention, unless otherwise specified terms shall be as follows. The dimming device of the present invention relates to a configuration of a power circuit portion so-called dimming unit that has a phase control circuit and a control means for directly controlling the phase control circuit, and actually a dimming control circuit portion that produces lighting. Is often used in addition. However, the present invention is not limited to such a combination.
[0009]
<Regarding First Phase Control Unit> The first phase control unit is controlled by a control unit to be described later, and takes charge of the entire phase control at the time of rising of the phase control of the AC voltage and light load.
[0010]
Further, the first phase control circuit includes a self-extinguishing control element, and is controlled by a control means to be described later at the start of the AC voltage phase control so that the phase of the AC voltage half-wave is a phase by the rank phase control. Start control. As the self-extinguishing control element, for example, IGBT, MOSFET, SIT or the like can be used. In order phase control, so-called tilt control that increases the rising of the current in a gradient manner, in other words, linear on-operation is performed.
[0011]
The circuit configuration for controlling the phase of the AC power supply voltage is not limited to a specific circuit. For example, a pair of self-extinguishing control elements are connected in series with opposite polarities, and a diode is connected in parallel with each of the pair of self-extinguishing control elements in parallel with each other, or a diode bridge is connected between a pair of opposing vertices. A configuration in which two self-extinguishing control elements are connected can be used.
[0012]
<Regarding Second Phase Control Unit> The second phase control unit is controlled by a control unit which will be described later, takes charge of the load current after rising of the phase control of the AC voltage, and does not operate at a light load.
[0013]
Further, the second phase control circuit is inserted into the AC power supply line, and in the desired phase of the AC voltage half-wave when the load is not light , the control means to be described later following the first phase control circuit. The thyristor is controlled to be turned on. The circuit configuration for controlling the phase of the AC power supply voltage is not limited to a specific circuit. Typically, a configuration in which a pair of thyristors are connected in reverse parallel can be used.
[0014]
<Regarding Load Current Detection Unit > The load current detection unit literally detects the load current. Specific means for detecting the load current is not limited to a specific configuration. For example, a current transformer, a current detection resistor, a semiconductor current detector, or the like can be used as appropriate. The insertion position of the load current detection means is arranged in series between the output end of the dimmer, that is, the load, and the first and second phase control circuits.
[0015]
<Regarding Control Unit> The control unit controls the first and second phase control circuits in a coordinated manner as described below. That is, the control means obtains the size of the load based on the detection data of the load current detection means. Then, in a desired phase of the AC voltage half-wave in a load state other than a light load , first, the first phase control circuit is operated by controlling the inclination of the self-extinguishing control element, and then the conduction, When the load current is almost saturated, a trigger signal, preferably a short-time trigger signal, is supplied to the thyristor of the second phase control circuit to perform the phase control operation. In the present invention, the “short-time trigger signal” is continuous for the time required for the thyristor to start, but before the end of the AC voltage half-wave, at least a reset time is ensured and the relative duration continues. A short trigger signal. The control means supplies a trigger signal, preferably a short-time trigger signal, to the thyristor and at least turns on the self-extinguishing control element at this time. Although the trigger signal supplied to the thyristor of the second phase control circuit is preferably a short-time trigger signal, it is a trigger signal that is continuous up to near the end of the AC voltage half-wave as in Patent Document 1. However, it is sufficient that the reset period is secured.
[0016]
With the above configuration of the control means, the first phase control circuit may be turned off while the short-time trigger signal of the thyristor is supplied and may be turned on again almost simultaneously with the end of the short-time trigger signal. Alternatively, the thyristor may be kept on while the short-time trigger signal is supplied following the tilt control. This is because the self-extinguishing type control element has a voltage drop when conducting that is larger than that of the thyristor, and thus can turn on the thyristor even while it is on.
[0017]
The control means does not supply a trigger signal to the thyristor and operates the first phase control circuit when the magnitude of the load obtained based on the detection data of the load current detection means is a predetermined value or less, that is, a light load. . The “load magnitude” means the magnitude of load power or load current. In order to operate the first phase control circuit, a drive signal for the self-extinguishing control element is supplied. However, the drive signal may be continuously supplied after the tilt control, or a short-time interruption is performed. A driving signal may be supplied after the period. Furthermore, “when the load is equal to or less than a predetermined value, that is, a light load” can be set as desired. However, setting it to 20% or less of the rated current is a relatively reasonable value for practical use.
[0018]
Further, the control means can control the first phase control circuit when the load is other than the light load, and when the load is other than the slope control, as in the case of the light load. However, the first phase control circuit may not be operated if desired.
[0019]
<Operation of the Present Invention> Since the present invention has the above-described configuration, the first phase control circuit self-extinguishes when the phase control is started up by the control of the control means regardless of the load level. Inclination control is performed by the arc-shaped control element, and when the conduction is almost saturated, a trigger signal is supplied to the thyristor of the second phase control circuit. In charge of the phase control.
[0020]
Next, a case where a short time trigger signal is supplied will be described. That is, in the AC voltage half-wave, the first phase control circuit is first activated by the tilting operation to start the phase control of the load current. In the first phase control circuit, when the self-extinguishing control element is turned on, that is, when the load current is almost saturated, a short time trigger signal is supplied from the control means to the thyristor of the second phase control circuit. If the load is small, that is, not light, the thyristor is turned on when a short time trigger signal is supplied. When the thyristor is turned on, even if the self-extinguishing control element is continuously turned on, the load current of the second phase control circuit is smaller than that of the self-extinguishing control element. Flows through the thyristor.
[0021]
When the AC voltage half-wave is finished and its polarity is reversed, the trigger signal is already finished for a short time and the reset time has passed, so that the thyristor is automatically and reliably turned off.
[0022]
When the polarity of the AC voltage is reversed to the next half wave, the same operation is repeated again for the AC voltage half wave having the opposite polarity. Thus, load phase control, that is, dimming is performed.
[0023]
Next, operation at light load will be described. That is, when the magnitude of the load obtained by the control means based on the load current detection data from the load current detection means is equal to or less than a preset value, no trigger signal is supplied to the thyristor of the second phase control circuit. . At the same time, a drive signal is supplied to the self-extinguishing control element of the first phase control circuit. As a result, when the load is light, the phase control is performed only by the first phase control circuit. Therefore, it is possible to prevent the occurrence of brightness flicker due to the failure of starting the thyristor. The self-extinguishing control element has a larger voltage drop when conducting than the thyristor as described above, but since it is a light load, there is no practical problem due to heat generation.
[0024]
The features of the present invention described above are summarized as follows.
[0025]
1. Since the phase control is performed by the first phase control circuit including the self-extinguishing element without turning on the thyristor at light load, it is possible to prevent the occurrence of brightness flicker due to the thyristor not turning on.
[0026]
2. Since the phase control by the self-extinguishing element of the first phase control circuit is only at a light load, there is no practical problem due to heat generation.
[0027]
3. Other features (1) A self-extinguishing control element having a relatively small rated current value can be employed. Self-extinguishing control element, since only by performing the phase control at the time of on-operation and light load by tilting control, it is possible to first phase control circuit is set small load current in charge. Therefore, a self-extinguishing control element having a relatively small rated current value can be employed.
(2) The load does not generate acoustic noise. By the slope control by the self-extinguishing control element of the first phase control circuit, the rise of the load current becomes gentle (di / dt is small), and the load does not generate acoustic noise.
(3) The self-extinguishing control element is not easily damaged. Since the self-extinguishing control element can always be used below the maximum instantaneous allowable current value, the self-extinguishing control element is hardly damaged.
(4) A dummy resistor connected in parallel with the load is not required to turn on the thyristor at light load.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0029]
1 and 2 show a first reference example in the light control device of the present invention, FIG. 1 is a circuit block diagram, and FIG. 2 is a voltage / current waveform diagram for explaining the operation timing of each part. In FIG. 1, AS is an AC power source, DM is a dimmer, and IL is a load.
[0030]
The AC power supply AS is a commercial AC power supply or the like.
[0031]
The dimming device DM includes a first phase control circuit PC1, a second phase control circuit PC2, and a control means CC, and a pair of AC power supply lines l1 and l2 whose input ends extend from both poles of the AC power supply AS and a load. Connect to AC power supply AS via IL.
[0032]
The first phase control circuit PC1 includes a self-extinguishing control element that is inserted in series with one AC power supply line l1 and phase-controls the AC voltage. In the present embodiment, it includes a pair of self-extinguishing control elements Q1, Q2 and a pair of diodes D1, D2. The pair of self-extinguishing control elements Q1 and Q2 are made of, for example, an IGBT, and are connected in series with the opposite polarity and in the AC power supply line l1. The pair of diodes D1 and D2 are connected in antiparallel to the respective self-extinguishing control elements Q1 and Q2.
[0033]
Similarly, the second phase control circuit PC2 includes a thyristor that is inserted in series with one AC power supply line l1 and is therefore connected in parallel to the first phase control circuit PC1 to control the phase of the AC voltage. In this embodiment, it consists of a pair of thyristors T1 and T2. The pair of thyristors T1 and T2 are connected in antiparallel to each other.
[0034]
The control means CC is configured to include a microcomputer, and is operated by being energized from the AC power supply AS so as to control the first and second phase control circuits PC1 and PC2 to cooperate with each other. That is, the phase control by the slope control by the first phase control circuit PC1 is first performed on the half voltage of the power supply voltage. When the self-extinguishing control elements Q1, Q2 are turned on, that is, when the load current is almost saturated, a short-time trigger signal is supplied to the thyristors T1, T2 of the second phase control circuit PC2 to turn on the thyristors T1, T2. Instead of the first phase control circuit PC1, the second phase control circuit PC2 performs phase control.
[0042]
The load IL is an incandescent lamp.
[0035]
Next, the circuit operation of the light control device in this reference example will be described with reference to FIG. 2, (a) is an AC power supply voltage waveform, (b) is a drive signal current waveform of a self-extinguishing control element, (c) is a short-time trigger signal current waveform, and (d) is a phase control output voltage waveform. Are conceptually shown.
[0036]
In other words, the control terminal circuit of the self-extinguishing control element Q1 with the desired phase of the sine AC half-wave shown in FIG. When the first signal portion A having an inclined edge is passed, the self-extinguishing control element Q1 starts the tilting operation according to the inclination of the first signal portion A, and the load current is changed to that of the AC power supply AC. 1, the load current sequentially increases in the path of the lower pole in FIG. 1 of the upper pole, AC power supply line 11, self-extinguishing control element Q 1, diode D 2, load IL, AC power supply line 12, and AC power supply AC. Inclination is performed at the rising edge of the flow and phase control.
[0037]
When the load current is almost saturated, the control means CC next stops the first signal portion A and simultaneously causes the short-time trigger signal current shown in FIG. 2C to flow through the gate circuit of the thyristor T1. Thereby, since the thyristor T1 is turned on this time, the phase control output voltage shown in FIG. 2 (d) is applied to the load IL, and accordingly, the load current is changed from the first phase control circuit PC1 to the second phase control. Instead of the thyristor T1 of the circuit PC2, the rest flows through the above-mentioned path.
[0038]
When the short-time trigger signal current ends, the thyristor T1 maintains the on state. Then, the control means CC causes the drive signal current of the self-extinguishing control element Q1 of the first phase control circuit PC1 to flow again as shown in the second part B of FIG. The arc control element Q1 is turned on again. However, since the voltage drop of the thyristor T1 connected in parallel to the self-extinguishing control element Q1 is smaller, the load current does not flow to the self-extinguishing control element Q1.
[0039]
Therefore, even when the thyristor T1 is not turned on due to the short-time trigger signal current at light load, the self-extinguishing control element Q1 flows the load current instead of the thyristor T1.
[0040]
Then, when the AC voltage is inverted and a half wave of opposite polarity is applied between the AC power supply lines 11 and 12, this time, the self-extinguishing control element Q2 and the diode D1 of the first phase control circuit PC1. Is turned on and the thyristor T2 of the second phase control circuit PC2 is turned on, but operates in the same manner as described above, as shown in the right half of FIG. As a result, phase control is performed for each half wave of the polarity of each AC voltage.
[0041]
FIG. 3 is a voltage / current waveform diagram for explaining the operation timing of each part showing the second reference example in the light control device of the present invention. The same parts as those in FIG. This embodiment corresponds to the invention of claim 1.
[0042]
That is, this reference example is different in that the first part A and the second part B in FIG. 2 of the drive signal current for the self-extinguishing control element Q1 of the first phase control circuit PC1 are continuous. The circuit operation is basically the same as that in the first reference example .
[0043]
4 and 5 show an embodiment of the light control device of the present invention, FIG. 1 is a circuit block diagram, and FIG. 2 is a voltage / current waveform diagram for explaining the operation timing of each part. In addition, in each figure, the same code | symbol is attached | subjected about the same part as FIG. 1 and FIG. This embodiment corresponds to the invention of claim 2.
[0044]
That is, in the present embodiment, the load current detecting means CD is provided, and the detected data is control-inputted to the control means CC. The load current detection means CD comprises a current transformer, and is magnetically coupled to the AC power supply line l1 between the first and second phase control circuits PC1, PC2 and the load IL. Then, the load current is detected and input to the control means CC described later.
[0045]
Then, when the load current is less than or equal to the predetermined value, the control means CC stops supplying the trigger signal current to the thyristors T1 and T2 of the second phase control circuit PC2. For this reason, the self-extinguishing control elements Q1 and Q2 of the first phase control circuit PC1 perform phase control instead.
[0046]
【The invention's effect】
According to the present invention, the control means obtains the magnitude of the load based on the detection data of the load current detection means, and when the load magnitude is not a light load greater than a predetermined value , the first phase is obtained with the desired phase of the AC voltage half-wave. When the self-extinguishing control element of the phase control circuit of the second phase control circuit is operated by tilt control, and when the conduction is almost saturated, a trigger signal is supplied to the thyristor of the second phase control circuit, in magnitude of the load does not supply a trigger signal to when the predetermined value or less thyristor of the second phase control circuit, and configured the control means so that I line phase control only by the first phase control circuit By providing the above, it is possible to provide a light control device that prevents flickering of brightness due to failure of ignition of the thyristor at a light load.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a first reference example in the light control device of the present invention. FIG. 2 is a voltage / current waveform diagram illustrating the operation timing of each part. illustrating the operation timing of the circuit block diagram Figure 5 also each part of an embodiment of the light control device of the voltage-current waveform diagram invention; FIG explaining the operation timing of each section showing the second reference example Voltage / current waveform diagram [Explanation of symbols]
AS ... AC power supply, CC ... control means, CD ... load current detection means, DM ... light control device, IL ... load, l1, l2 ... AC power supply line, PC1 ... first phase control circuit, PC2 ... second phase Control circuit, Q1, Q2 ... Self-extinguishing control element, T1, T2 ... Thyristor

Claims (1)

A first phase control circuit having a self-extinguishing control element inserted into an AC power supply line and phase-controlling an AC voltage;
A second phase control circuit including a thyristor inserted into an AC power supply line and phase-controlling an AC voltage;
Load current detection means for detecting a load current arranged in series between the first and second phase control circuits and the load ;
The thyristor of the second phase control circuit is operated when the self-extinguishing control element of the first phase control circuit is operated by tilt control at the desired phase of the AC voltage half-wave, and then the conduction is almost saturated. And a trigger signal is supplied to the thyristor of the second phase control circuit when the magnitude of the load is equal to or less than a predetermined value. not supply, and configured the control means so that I line phase control only by the first phase control circuit;
A light control device comprising:

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