JP2003077686A - Automatic switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate a switch without using a zero voltage switching circuit in the same way as in the case where zero voltage switching is used out, thereby simplifying the circuit structure, reducing the number of used parts, and decreasing the costs. SOLUTION: To a commercial AC power 1, a lighting load 3 is connected through a bi-directional triode thyristor 2, and a filter capacitor 5 is connected through a diode 4. The filter capacitor is connected in parallel to a charge and discharge capacitor 7 through a resistor 6, a DIAC 8 is connected between the connecting point of the resistor with the capacitor 5, and the gate of the thyristor, thereby forming a saw-tooth oscillating circuit for generating saw-tooth oscillation at a high frequency. A photoelectric element 9 for reducing an internal resistance in proportion to an illumination level of the exterior light is connected in parallel to the charging and discharging capacitor. At night, when the internal resistance in the photoelectric element increases, the saw-tooth oscillating circuit oscillates at a high frequency, and the thyristor performs conduction and non-conduction operation equal to those at the zero voltage switching, so that the lighting load is turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic switch device for automatically turning on and off lighting such as street lights and indoor lights and home appliances.

[0002]

2. Description of the Related Art An automatic switch device, for example, an automatic switch device for lighting, connects an AC power source to a lighting load such as a lamp through a bidirectional three-terminal thyristor, and has an internal resistance value proportional to the illuminance level of external light. A photosensor such as a photoconductive element that changes the output voltage or a solar cell that changes the output voltage in proportion to the illuminance level of external light is used. The load is automatically turned on, and when the surroundings become bright, the thyristor is shut off and the lighting load is automatically turned off.

In such an automatic switching device, there is a problem of radio noise and harmonics generated when controlling conduction and non-conduction of the thyristor.

[0004]

Therefore, conventionally, the zero voltage switching circuit is used to perform zero voltage switching of the thyristor to prevent generation of radio noise and harmonics. However, the use of the zero-voltage switching circuit has a problem that the circuit configuration becomes complicated, the number of parts used increases, and the cost also increases.

Therefore, the present invention can perform an operation equivalent to that in the case where zero voltage switching is performed without using the zero voltage switching circuit, thereby simplifying the circuit configuration, reducing the number of parts used, and reducing the cost. Provided is an automatic switch device capable of performing the above.

[0006]

According to the present invention, a load connected to an AC power supply via a bidirectional three-terminal thyristor, a smoothing capacitor connected to the AC power supply via a rectifier, and a resistor connected to this smoothing capacitor. Connect the charging / discharging capacitor in parallel and connect the connection point between the resistor and the charging / discharging capacitor.
Connect a 2-terminal trigger element between the gate of the terminal thyristor and a saw-tooth wave oscillator circuit that supplies a high frequency pulse waveform current to the gate of the 3-terminal thyristor to turn on the thyristor within a phase angle of 1 °. It is composed of a photoelectric conversion element that changes the internal resistance value according to the illuminance level of, and the change in the illuminance of the surroundings is detected by the photoelectric conversion element, and the charge level of the charging / discharging capacitor is changed to automatically turn the load on and off. It is in an automatic switch device.

According to the present invention, a lighting load is connected to an AC power supply via a bidirectional three-terminal thyristor, a smoothing capacitor is connected to the AC power supply via a rectifier, and the smoothing capacitor is charged / discharged via a resistor. Connect a capacitor in parallel and connect a 2-terminal trigger element between the connection point between the resistor and the charge / discharge capacitor and the gate of the 3-terminal thyristor, and turn on the thyristor to the gate of the 3-terminal thyristor within a phase angle of 1 °. A sawtooth wave oscillating circuit that supplies a high frequency pulse waveform current is formed, and a photoconductive element that reduces the internal resistance value in proportion to the ambient illuminance level is connected in parallel to the charge / discharge capacitor. This is an automatic switch device that detects changes in ambient illuminance and automatically turns the lighting load on and off.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, as shown in FIG. 1 in which the present invention is applied to an automatic blinking device for lighting, lighting such as a street lamp or an interior lamp is provided to a commercial AC power source 1 via a bidirectional three-terminal thyristor 2. A load 3 is connected, and a smoothing capacitor 5 is connected to the commercial AC power source 1 through a diode 4 which is a rectifier via a polarity shown in the figure. The lighting load may be the lamp itself or the discharge lamp lighting device.

A charging / discharging capacitor 7 is connected in parallel to the smoothing capacitor 5 via a resistor 6, and a two-terminal trigger is provided between the connection point between the resistor 6 and the capacitor 7 and the gate of the three-terminal thyristor 2. A diac 8 which is an element is connected, and the resistor 6, the charging / discharging capacitor 7, and the diac 8 form a sawtooth wave oscillation circuit which causes sawtooth wave oscillation at a high frequency. As the photoelectric conversion element, a photoconductive element 9 whose internal resistance value decreases in proportion to the ambient illuminance level is connected in parallel to the charge / discharge capacitor 7.

In this automatic flashing device, when 100V power is supplied as the commercial AC power supply 1, a DC voltage of 100 × √2V is generated across the smoothing capacitor 5. This DC voltage is applied to the series circuit of the resistor and the parallel circuit of the charge / discharge capacitor 7 and the photoconductive element 9.

In the daytime, since the ambient illuminance level is high, the internal resistance value of the photoconductive element 9 is close to 0 and the charging / discharging capacitor 7 is not charged. In this state, at sunset, the ambient illuminance level decreases and the internal resistance value of the photoconductive element 9 gradually increases. Then, at night, the internal resistance value becomes considerably high and becomes substantially infinite, and the charge level of the charging / discharging capacitor 7 becomes high and exceeds the breakover voltage of the diac 8.

When the diac 8 breaks over, the charging / discharging capacitor 7 is discharged through the diac 8 and a discharge current flows through the gate of the thyristor 2. As a result, the thyristor 2 is turned on and the lighting load 3 is turned on. Or later,
While the night continues, the sawtooth wave oscillation circuit causes sawtooth wave oscillation at a high frequency, the pulse waveform current is supplied to the gate of the thyristor 2 at a short cycle, and the thyristor 2 has a small phase angle every half cycle. After that, the lighting load 3 is kept turned on and the lighting load 3 substantially maintains the lighting state.

For example, in a commercial power source 1 of 50 Hz,
It takes 18,000th of a second to advance the phase by 1 °. On the other hand, the resistance value of the resistor 6 is 50 KΩ, and the capacitor 7
If the capacitance is 0.01 μF, the sawtooth wave oscillation circuit oscillates at a high frequency of approximately 18 KHz, and
The pulse waveform current of 80,000 times is supplied to the gate of the thyristor 2. As a result, the thyristor 2 turns on and becomes conductive within a phase angle of 1 °, which is a very early time when the power supply voltage is approximately 0V.

In this way, the thyristor 2 is turned on and becomes conductive within a phase angle of 1 °, which is very close to 0 V, every half cycle of the commercial power supply AC. In this case, the phase angle at which the thyristor 2 is non-conductive is 1 °
Within a very short time. At this time, the lacking voltage of the AC power supply voltage is within 2.4 V as shown in FIG. 2, which is a value very close to 0 V when seen from the AC power supply voltage of 100 V, which is almost the same as the case of zero voltage switching. . That is, the same operational effect as when the zero voltage switching circuit is used without using the zero voltage switching circuit is obtained.

In this way, the thyristor 2 is repeatedly turned on every half cycle of the commercial power supply AC, and the lighting load 3 is turned on.
An AC voltage waveform is supplied to the AC voltage waveform, but the AC voltage waveform at this time is a substantially sine wave. In this way, the lighting load 3 comes to perform a favorable lighting operation.

Then, as time elapses and the sun rises, the illuminance level of external light rises with the sun rise, and the internal resistance value of the photoconductive element 9 decreases. Then, the charge level of the charge / discharge capacitor 7 does not exceed the breakover voltage of the diac 8, and the oscillation of the sawtooth wave oscillation circuit is stopped. As a result, the lighting load 3 is turned off.

Even if the thyristor 2 is controlled to be conductive or non-conductive in this way, a sine wave voltage having a minute waveform distortion equivalent to that at the time of zero voltage switching can be supplied to the lighting load 3, so that the non-conductive state is changed to a conductive state. There is almost no occurrence of radio noise or harmonics due to the steep rise of the current when it becomes low. That is, since the generation of radio noise and harmonics can be suppressed without using the zero voltage switching circuit, the circuit configuration can be simplified, the number of parts used can be reduced, and the cost can be reduced.

Further, since the turn-on and turn-off of the thyristor 2 are determined by the presence / absence of oscillation of the sawtooth wave oscillating circuit, the illumination load 3 is illuminated with respect to the illuminance level state when the illumination load 3 is turned off or switched from off to on. The chattering phenomenon in which the load frequently turns on and off does not occur, and relatively stable operation can be performed. Therefore, the hysteresis circuit for preventing the chattering phenomenon is unnecessary. Further, since no radio noise is generated, a harmonic filter is unnecessary.

In this embodiment, the present invention is applied to the automatic lighting blinking device, but the present invention is not limited to this. For example, the present invention can be applied to one that uses a home electric appliance such as a television as a load. In this case, the power of the home electric appliance is turned off when the room becomes dark, and the power of the home electric appliance is turned on when the room becomes bright. That is, the on / off control opposite to the lighting load is performed.

To realize this, for example, when the internal resistance value of the photoconductive element 9 decreases, the charge level of the charge / discharge capacitor 7 increases, and when the internal resistance value of the photoconductive element 9 increases, the charge / discharge capacitor. The circuit may be configured so that the charge level of 7 is low. Alternatively, instead of the photoconductive element 9, a photoelectric conversion element whose internal resistance value increases in proportion to the ambient illuminance level may be used.

[0021]

As described in detail above, according to the present invention,
It is possible to provide an automatic switch device capable of performing the same operation as in the case where zero voltage switching is performed without using the zero voltage switching circuit, thereby simplifying the circuit configuration, reducing the number of parts used, and reducing the cost. .

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a power supply voltage waveform flowing through a lighting load in the embodiment.

[Explanation of Codes] 2 ... Bidirectional 3-terminal thyristor, 3 ... Lighting load, 4 ... Diode (rectifier), 5 ... Smoothing capacitor, 6 ... Resistor, 7
... Charging / discharging capacitor, 8 ... Diac, 9 ... Photoconductive element

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K073 AA13 AA49 AA50 AB01 BA27                       CA01 CF13                 5H420 BB04 BB12 CC04 DD03 EA05                       EA39 EB02 EB38 FF03 HJ03                 5J005 FA01                 5J050 AA15 AA49 BB16 CC03 DD12                       EE21 EE34 FF09

Claims (2)

[Claims] 1. A load connected to an AC power supply via a bidirectional three-terminal thyristor, a smoothing capacitor connected to the AC power supply via a rectifier, and a charge / discharge capacitor connected in parallel to this smoothing capacitor via a resistor. In addition, a two-terminal trigger element is connected between the connection point of the resistor and the charge / discharge capacitor and the gate of the three-terminal thyristor, and the thyristor is connected to the gate of the three-terminal thyristor with a phase angle of 1 °.
It consists of a sawtooth wave oscillation circuit that supplies a high frequency pulse waveform current that turns on within ° and a photoelectric conversion element that changes the internal resistance value according to the ambient illuminance level. Is detected, the charge level of the charge / discharge capacitor is varied to automatically turn on / off the load. 2. A lighting load connected to an AC power supply via a bidirectional three-terminal thyristor, a smoothing capacitor connected to the AC power supply via a rectifier, and a charging / discharging capacitor connected in parallel to the smoothing capacitor via a resistor. A two-terminal trigger element is connected between the connection point of the resistor and the charge / discharge capacitor and the gate of the three-terminal thyristor.
A sawtooth wave oscillating circuit for supplying a high frequency pulse waveform current for turning on the gate of the three-terminal thyristor within a phase angle of 1 °, and an internal resistance value reduced in proportion to an ambient illuminance level, A photoconductive element connected in parallel to a charge / discharge capacitor, the ambient light intensity change is detected by the photoconductive element, the charge level of the charge / discharge capacitor is varied, and the lighting load is automatically turned on,
An automatic switch device characterized by off control.