JP2007179909A - Incandescent lamp dimmer and electric power control method for incandescent lamp dimmer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dimmer capable of stopping excessive current at a certain value when the excessive current is about to flow by arc discharge following filament breakage of a bulb to protect the dimmer while allowing incandescent lamps except for the one with broken filament to be lighted continuously. <P>SOLUTION: The incandescent lamp dimmer includes a current detector for detecting excessive current owing to arc discharge following the filament breakage of the incandescent lamp temporarily cuts electric power supply by an electric power controlling part based on detection of the current detector and then restarts the electric power supply after a certain time has elapsed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to measures against excessive current in an incandescent lamp dimmer used in theaters, TV studios, and the like. More specifically, the present invention relates to an incandescent lamp (incandescent lamp) connected as a load of the dimmer at the end of the life of the lamp. The present invention relates to an incandescent lamp dimmer having a function of quickly stopping arc discharge when a filament is broken and arc discharge is generated, and preventing various problems associated with arc discharge.

  Conventionally, as a dimmer for an incandescent lamp, for example, there is one that performs power control using thyristors 3 and 4 as power control elements as shown in FIG.

  In FIG. 4, 1 is an AC power supply for illumination, 2 is an overcurrent circuit breaker, 3 and 4 are thyristor elements connected in antiparallel, 5 is a reactor, 7 is an ignition phase angle control circuit for the thyristor elements, and 8 is incandescent. A lamp illuminator, 9 is an external controller, and 10 is a dimmer body.

  However, the thyristor dimmer shown in FIG. 4 may cause a problem as described in detail below when the incandescent lamp such as a halogen bulb is used as a load and the bulb filament breaks at the end of the bulb life. is there. FIG. 6 shows an example of the behavior in this case, and shows the waveform of the output voltage of the dimmer and the current flowing through the incandescent lamp (hereinafter referred to as “lamp current”). For simplicity, the output voltage of the dimmer is assumed to be close to 100%.

  In FIG. 6, if the filament is disconnected at the end of its life at time T1, arc discharge starts at a very small interval between the filaments, the temperature becomes extremely high locally, the filament evaporates, and arc discharge grows in the meantime. FIG. 6 shows how the lamp current increases as the arc discharge grows.

  At time T2, arc discharge grows between the lead-in lines of the bulb, and the lamp current increases to a value almost determined by the impedance of the distribution line. At time T3, since the fuse enclosed in the bulb is blown by an excessive current, the lamp current is cut off and the arc discharge is stopped. Since the time during which an excessive current flows from time T1 to T3 is as short as 0.1 to 0.2 seconds, the overcurrent circuit breaker 2 in FIG. 4 does not operate, but the overcurrent capability of the thyristors 3 and 4 and the reactor 5 is Due to the relatively large size, the bulb is generally turned off without damaging the dimmer. However, a very large current flows through the thyristors 3 and 4 when the selection of the fuse enclosed in the bulb is inappropriate or the fusing characteristics vary.

  In particular, when the time from T2 to T3 becomes long, the bulb internal pressure suddenly increases due to arc discharge, and the bulb may burst. If a light bulb bursts during a performance on a theater stage or a TV studio, not only will the fragments of the light bulb scatter, but the sound of the light bulb will cause a major hindrance to the performance. I can say that.

  As described above, the thyristors 3 and 4 have a feature that the overcurrent withstand capability is large. However, since the terminal voltage and current of the load become a sawtooth wave and interfere with the acoustic equipment, the IGBT (Insulated gate bipolar transistor) has recently been used. ) Is used as a power control element. The dimmer shown in FIG. 5 is a dimmer using a step-down chopper using an IGBT element.

  In FIG. 5, 1 is an AC power source for lighting, 2 is an overcurrent circuit breaker, 8 is an incandescent lamp lighting device, 12 is a filter circuit for reducing high-frequency current flowing out to the power source side due to the operation of the step-down chopper, A step-down chopper dimming circuit 13 includes an AC smoothing circuit 33 including a choke coil and a capacitor on the output side. Reference numeral 14 denotes a control circuit having a function of sending a PWM signal to the main IGBT 31 by a dimming signal from the external console 9 and controlling the flywheel IGBT 32. Reference numeral 11 denotes a dimmer main body including them.

  In this case as well, as with the thyristor dimmer, there is a risk of the occurrence of an IGBT element breakage or a bulb rupture accident caused by arc discharge of the bulb. In particular, the IGBT element has a lower overcurrent withstand capability than the thyristor, and the demand for protection becomes stronger.

  On the other hand, as a conventional technique, an IGBT is used as a power control element. For protection, a current detector detects a current flowing through a load and cuts off an excessive current when a load short circuit occurs. Yes (see Patent Documents 1 and 2).

  However, this technology only keeps the cut-off state once the current flowing through the load is cut off. If this is used for a dimmer, all of the lights connected to the output will be turned off. As a result, there will be a major hindrance to performances in theaters. Therefore, the protection of the dimmer is sufficient, but there is room for improvement in that the original function of the dimmer is lost.

US Pat. No. 5,714,847 US Pat. No. 5,500,555

  The present invention has been made in view of the above-described conventional circumstances, and the object of the present invention is that when an excessive current is about to flow due to arc discharge accompanying the filament breakage of the bulb for protection of the dimmer. Is to provide a dimming device that can continuously illuminate an incandescent lamp other than the incandescent lamp whose bulb is disconnected.

  In other words, incandescent lighting fixtures used in theater stage and TV studio lighting systems, the filament breaks at the end of the bulb's life, and if an arc discharge occurs at this time, an excessive current flows, causing the bulb to rupture or dimm. In contrast to the risk of failure of the power control element of the lamp, when the light bulb starts arc discharge, it quickly detects an overcurrent, stops the arc discharge, ruptures the light bulb, and dimmer power. To provide a light control device that protects a control element and that can be continuously lit while other light fixtures connected to the output of the dimmer are extinguished for a minimum time that is not visually recognized. It is the subject of the present invention.

  In order to solve the above problems, in the first invention, in the incandescent lamp dimmer having a power control unit for controlling the power supplied to the incandescent lamp as a load for dimming, the filament breakage of the incandescent lamp A current detector for detecting an excessive current state caused by arc discharge, temporarily interrupting the power supply by the power control unit based on the detection by the current detector, and then returning the power supply after a certain period of time It is characterized by making it.

Here, the “power control unit” may be any unit that is provided with an AC power supply for dimming and controls the output voltage by controlling the power. As the power control element, a thyristor element or an IGBT element may be used.
“Current detector” refers to a current transformer generally called CT, and includes a device that detects current using a low resistor or a Hall element.

  “Temporarily shut off and then return after a certain period of time” means that the temperature of the electrode that caused the arc discharge decreased after the current flowing through the output was cut off by detecting an excessive current due to arc discharge with a current detector. This means that the shut-off is released and the output is restored after a minimum time has passed so that ionization of the sealed gas accompanying arc discharge disappears. The cut-off time required to prevent arc discharge from restarting varies depending on the capacity and type of the bulb, the distance between the lead-in lines, the type and gas pressure of the enclosed gas, and the 1 kW halogen commonly used in the stage and TV studios. For light bulbs, it is 0.02 to 0.04 seconds (between 1 and 2 cycles at 50 Hz).

  According to the second aspect of the present invention, in the incandescent lamp dimmer having an electric power control unit for controlling the electric power supplied to the incandescent lamp as a load for dimming, an excessive current due to arc discharge accompanying filament breakage of the incandescent lamp A current detector for detecting the state, temporarily shuts off the power supply by the power control unit based on the detection by the current detector, and then when the power is automatically restored after a certain period of time, When the excessive current state persists, the power supply is shut off again, the cause of the excessive current is removed, and then the power supply is restored by manual intervention.

  “Returning output by manual intervention” means, for example, that a push button type reset switch is provided as means for returning output by manual intervention, and an ON signal is given to the power control unit manually. Means to restore the output. In this case, any output may be used as long as the output of the reset switch is indirectly given to a timer or a control switch for controlling ON / OFF of power and the signal is finally transmitted to the power control unit.

  According to a third aspect of the present invention, there is provided a comparator for comparing the detection result from the current detector with a threshold set by the threshold setting device, and a timer is operated by the output of the comparator, and a power control unit The operation of the power control unit is controlled by controlling a control signal supplied to.

  The “threshold setting device” may be, for example, a device that can set an analog value such as a potentiometer, or a device that can input a digital value if it is realized using a microcomputer.

  In setting the threshold value of the current detector, it is necessary to consider the inrush current when the incandescent lamp illuminator is turned on. This is because the filament resistance is very low when the incandescent bulb is extinguished, and when the operation of the output of the power control unit is suddenly increased, it instantaneously enters about 10 times the rated current of the bulb. Current flows in. Therefore, the threshold value of the current detector needs to be set to be not less than the inrush current value of the bulb and not more than the arc current value.

The “comparator” may be, for example, a comparator composed of an operational amplifier or the like, or may be realized using a microcomputer.
The “timer” outputs a set signal at the start of counting, interrupts the dimmer output, and returns the output at the end of counting. You may implement | achieve with an analog element and may implement | achieve using a microcomputer.

  In the fourth invention, the “certain time” is such that ionization of the sealed gas accompanying arc discharge of the incandescent lamp disappears after an excessive current due to arc discharge is detected by a current detector and power supply is cut off. It is characterized by the time of

  According to a fifth aspect of the present invention, in a dimmer to which an incandescent lamp is connected as an input to which an alternating current power supply is input, a power control unit that controls power supplied to the load for dimming, and a current that flows through the incandescent lamp A current detector for detecting the magnitude of the incandescent lamp, a threshold setting device for setting a detection threshold for excessive current in the event of arc discharge due to filament breakage of the incandescent lamp, and a threshold setting device A comparator that compares the detected threshold value with a current value flowing through the incandescent lamp, detects that the current value is greater than the detected threshold value, and sends a set signal for power interruption; A timer that cuts off the power for a predetermined time after receiving the set signal from the comparator and then sends a signal for supplying power again, and controls the increase / decrease of the power to the power control unit based on the dimming control signal from the outside Control signal to generate And generator, based on a signal sent from the timer, and further comprising a control switch for the signal from the control signal generator for a period of time OFF.

“External dimming control signal” usually refers to a dimmer signal sent from an external console. This control signal may be an analog signal or a digital signal called DMX.
By using the microcomputer, a comparator, a timer, a control signal generator, and a control switch can be realized.
The “control signal generator” receives a dimming control signal from the outside and generates a signal for controlling increase / decrease in power via the control switch.
The “control switch” is provided to turn ON / OFF the output of the power control unit based on the ON / OFF signal from the timer for the signal of the control signal generator sent to the power control unit.

  As described above, the present invention has a current detector on the output side of the dimmer for the incandescent lamp, detects arc discharge occurring at the end of the life of the bulb with this current detector, and controls power using a timer. By shutting off the control signal of the unit for a short time and shutting off the dimmer output, the arc discharge of the bulb can be stopped, and a bulb rupture accident can be prevented. In addition, the power control element in the dimmer can be prevented from being damaged due to an excessive current. In addition, by minimizing the change in lighting light except for arc discharge connected to the same dimmer, the dimmer output cut-off time is set to the shortest time within a range where arc discharge does not recur. Has many effects.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
An example of the configuration of an incandescent lamp dimmer according to the present invention is shown in FIG. In FIG. 1, reference numeral 1 denotes an AC power source, which is usually called an illumination power source. A power control unit 21 corresponds to the thyristor dimmer main body 10 shown in FIG. 4 or the IGBT dimmer main body 11 shown in FIG. 6 is a current detector, 15 is a comparator, 16 is an overcurrent detection threshold value setting unit, and 17 is a timer, and when an overcurrent is detected, an OFF signal is sent to 18 control switches for a certain period. 19 is a control signal generator, and 18 control switches turn 19 control signals ON and OFF according to the signal of the timer 17.
1, 4, and 5 have the same operational effects, and the thyristor dimmer main body 10 shown in FIG. 4 and the IGBT dimmer main body 11 shown in FIG. The configuration is as described above.

  Reference numeral 6 in FIG. 1 denotes a current detector that uses a current transformer, a low resistance, or a Hall element, which is usually called CT. Reference numeral 8 in FIG. 1 denotes a load illumination lamp, and an incandescent bulb is used as a light source. 9 is a remote controller that controls the brightness of the illuminating lamp by an external console, and is generally called a dimming console. The dimming control signal of the output is sent to the control signal via the control input terminal of the dimmer. Connected to generator 19.

  Reference numeral 19 denotes a control signal generator that supplies a control signal to the power control unit 21. In the case where the power control unit 21 is the thyristor dimmer 10 shown in FIG. When the power control unit 21 is the IGBT dimmer shown in FIG. 5, the PWM signal supplied to the main IGBT 31 is generated corresponding to the dimming control signal. An electronic control switch 18 is a control switch that opens and closes a power control signal supplied to the power control unit 21 at a high speed. When the control switch 18 is ON, the light control operation is normally performed. The output is cut off. The comparator 15 compares the output of the current detector 6 with the output of the threshold value setter 16, and sends a signal to the timer 17 when the output of the current detector 6 exceeds the output of the threshold value setter 16. The timer 17 sends an OFF signal to the control switch 18 for a certain period.

  In the incandescent lamp dimmer of the present example configured as described above, when an arc discharge occurs due to filament breakage in the illuminating lamp 8 of the dimmer load, an excessive current flows to the output of the dimmer, It is detected by the detector 6 and compared with the threshold value set by the threshold value setter 16 by the comparator 15. When the current value detected by the current detector 6 exceeds the threshold value, a set signal is supplied to the timer 17, the control switch 18 is turned OFF for a certain period of time, the output of the power control unit 21 is cut off, and the timer 17 is set. After a predetermined time, the control switch is turned on and the output of the power control unit 21 is automatically restored.

  FIG. 2 shows the behavior of the dimmer output voltage and the lamp current when the power control element is a thyristor (when the power control unit 21 is the thyristor dimmer 10). This is a case where 100V750W is used for the incandescent light bulb and the threshold value of the threshold setting device 16 is set to 150A. In FIG. 2, at time T1, the filament of the bulb is broken, arc discharge starts, and the lamp current increases. At time T2, the arc discharge reaches between the introduction lines. If an excessive current flows exceeding the threshold value of 150 A immediately after time T2, the power supply of the load is shut off by the control signal, but since the power control element is a thyristor, arc discharge continues during the half cycle, As for the output of the control unit, the dimmer output is cut off at time T4, and the cut-off state continues for 0.03 seconds until time T5.

  Even if the output of the power control unit 21 is automatically restored at time T5 after 0.03 seconds have elapsed, the temperature of the electrode that has caused arc discharge during the interruption period from time T4 to time T5 decreases, and the enclosure accompanying arc discharge occurs. Since the gas ionization disappears, the arc discharge is not resumed even if the output of the power control unit returns at time T5.

  The cut-off time required to prevent arc discharge from restarting depends on the capacity, type, distance between lead-in lines, type of sealed gas, and gas pressure, but it is a 1kW halogen bulb that is commonly used on stage and TV studios. Then, it is 0.02 seconds to 0.04 seconds (between 1 and 2 cycles at 50 Hz).

  If the arc discharge does not resume, the bulb will not rupture, and the peak value of the arc discharge reaches 280A, but the thyristor element has a long duration of 0.01 seconds and the overcurrent capability of the thyristor element is large. Is also protected. In this case, the overcurrent breaker 2 connected to the power source side of the dimmer does not operate. During this time, even if the output of the dimmer is cut off, the light of the other illumination lamp (8 ') connected to the dimmer is not visibly changed by the thermal inertia of the filament of the bulb. Absent.

  In this way, arc discharge due to filament breakage can be safely stopped in a short time to prevent a light bulb bursting accident, and failure due to continuation of excessive current of the power control element can also be avoided. Furthermore, it is possible to provide a dimmer that hardly affects other illumination lamps connected to the dimmer.

  FIG. 3 shows an operation example when a step-down chopper using an IGBT element is used as a power control element (when the power control unit 21 is an IGBT dimmer 11), and 750 W is used for the light bulb as described above. In this case, the threshold value of the threshold setting device 16 is also set to 150A. In this case, the arc current reaches a threshold value of 150 A, the control signal supplied to the IGBT element is cut off, and at the same time the output of the dimmer is cut off, and the peak value of the arc discharge is limited to 150 A. Even an IGBT element having a low overcurrent withstand capability is protected from an excessive current. Moreover, even if the dimmer output cut-off period from time T4 to time T5 is set short from the place where the peak value of arc current is low and the duration is short, arc discharge does not recur and the cut-off period is shortened to 0.01 seconds. I was able to. Thus, the present invention is particularly effective when a step-down chopper using an IGBT element is used as a power control element.

  Causes of overcurrent that may damage the power control element of the dimmer include not only the arc discharge of the light bulb described here, but also the case where an illuminating lamp with a rated capacity or more is connected as the load of the dimmer. A case where a short-circuit failure occurs in the electric line to the load and a short-circuit current occurs can be considered. In such a case, when the output of the power control unit 21 is simply restored automatically, an excessive current is detected again, the power is restored after a short time by the operation of the timer 17, and the output of the dimmer 22 is turned off. , ON may be repeated. Therefore, when the operation of the timer 17 is limited to once or twice and the output of the power control unit 21 is automatically restored, if an excessive current is still detected, the control switch 18 is turned off. After removing the cause of the excessive current, it is desirable to manually cancel the OFF state by the reset switch 34 and manually recover the output cutoff of the power control unit 21.

  Further, as described above, the comparator 15, the timer 17, the control switch 18, and the control signal generator 19 may be realized by a one-chip microcomputer. By configuring with a one-chip microcomputer, the entire dimmer becomes economical, and space saving can be realized, resulting in a compact device.

It is an example of the dimmer for an incandescent lamp according to the present invention. The operation example of the incandescent lamp dimmer using the thyristor as the power control element according to the present invention shows the behavior of the output voltage and the lamp current of the dimmer. The operation example of the incandescent lamp dimmer using the step-down chopper by IGBT as the power control element according to the present invention shows the behavior of the output voltage and the lamp current of the dimmer. This is a conventional dimmer using a thyristor as a power control element. This is a conventional dimmer using a step-down chopper by IGBT as a power control element. A conventional incandescent lamp dimmer using a thyristor as a power control element shows the behavior of the output voltage and lamp current of the dimmer when the filament breaks at the end of the bulb life and arc discharge occurs in the bulb. .

Explanation of symbols

1: Input power supply 6: Current detector 8: Incandescent lamp 9: External console 15: Comparator 16: Threshold setting unit 17: Timer 18: Control switch 19: Control signal generator 21: Power control unit 22: Adjustment Optical 34: Reset switch

Claims (6)

An incandescent lamp dimmer having a power control unit for controlling electric power supplied to an incandescent lamp as a load for dimming, comprising a current detector for detecting an excessive current due to arc discharge accompanying filament breakage of the incandescent lamp And a power control method for an incandescent lamp dimmer characterized by temporarily shutting off power supply by the power control unit based on detection by the current detector and then returning the power supply after a predetermined time has elapsed. . An incandescent lamp dimmer having a power control unit for controlling electric power supplied to an incandescent lamp as a load for dimming, comprising a current detector for detecting an excessive current due to arc discharge accompanying filament breakage of the incandescent lamp , When the overcurrent continues even when the power supply by the power control unit is temporarily cut off based on the detection by the current detector, and then the power is automatically restored after a certain period of time, A method of controlling electric power in an incandescent lamp dimmer, wherein the power supply is turned off again, the cause of excessive current is removed, and then the power supply is restored by manual intervention. A comparator for comparing the detection result from the current detector with the threshold set by the threshold setting device is provided, a timer is operated by the output of the comparator, and a control signal supplied to the power control unit is controlled. The power control method in the incandescent lamp dimmer according to claim 1, wherein the operation of the power control unit is controlled by the control. The predetermined time is set to a time enough to eliminate ionization of the enclosed gas accompanying the arc discharge of the incandescent lamp after the electric current supply is cut off by detecting an excessive current due to the arc discharge with the current detector. The electric power control method in the incandescent lamp dimmer according to any one of claims 1 to 3. In a dimmer in which an AC power source is input and an incandescent lamp is connected as a load, a power control unit that controls the power supplied to the load for dimming, and a current detection that detects the magnitude of the current flowing through the incandescent lamp A threshold value setting device for setting a detection threshold value of an excessive current at the time of arc discharge accompanying filament breakage of the incandescent lamp, the detection threshold value set in the threshold value setting device and the incandescent light A comparator that compares a current value flowing through the lamp, detects that the current value is greater than the detection threshold value, and sends a set signal for power interruption; and a set signal from the comparator Control signal generation for generating a signal for controlling power increase / decrease to the power control unit based on a dimming control signal from the outside and a timer for cutting off the power for a predetermined time and then supplying power again And the timer Based on the signal sent from an incandescent lamp dimmer, characterized in that it comprises a control switch for the signal from the control signal generator for a period of time OFF. 6. The incandescent lamp dimmer according to claim 5, wherein the comparator, the timer, the control switch, and the control signal generator are configured by a one-chip microcomputer.