JP2015060701A - Dimmer and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of flicker of a light source after recovery from instantaneous voltage drop.SOLUTION: A controller 22 of a dimmer 2 determines whether the rising interval of a synchronization signal is converged within a predetermined reference range, and stops output of a trigger signal when the interval is determined to be out of the reference range. When determining that the interval is converged within the reference range after the output of the trigger signal is stopped, the controller 22 resumes output of the trigger signal. When the frequency at which the interval is determined to be converged within the reference range after the resumption reaches a predetermined frequency, the controller 22 ceases output of the trigger signal to the synchronization signal of at least one period. Accordingly, an input voltage applied between connection terminals 23, 24 is equal to a power source voltage because the controller 22 ceases the output of the trigger signal, so that occurrence of flicker of a light source 10 after recovery from the instantaneous voltage drop can be suppressed.

Description

  The present invention relates to a dimmer and a lighting device including the dimmer and a lighting fixture.

  As a conventional example, a phase control type dimmer described in Patent Document 1 is illustrated. The phase control type dimmer adjusts the timing of turning on a self-holding semiconductor switching element that flows current in both directions, for example, a bidirectional three-terminal thyristor (triac), and is applied from an AC power source to a lighting fixture. Controls the conduction period (phase) of AC voltage (power supply voltage).

  When the light source of a lighting fixture is an incandescent lamp, the incandescent lamp can be dimmed directly by applying a power supply voltage phase-controlled by a dimmer. In addition, when the light source of the lighting fixture is a fluorescent lamp or LED light source, the lighting device mounted on the lighting fixture reads the dimming level from the conduction period of the phase-controlled power supply voltage, and corresponds to the read dimming level. Dimming the light source.

  The conventional example described in Patent Document 1 employs a so-called DC trigger method in which a trigger signal is continuously applied to the gate terminal of the triac during the conduction period. In other words, the DC trigger type dimmer generates a synchronization signal that becomes a high level when the power supply voltage exceeds a predetermined threshold, determines the conduction period from the rising edge of the synchronization signal, and determines the conduction A trigger signal is output within the period.

  By the way, in the case of the DC trigger type dimmer, when the instantaneous power failure (instantaneous power failure) of less than 1 second occurs in the AC power supply, the rising edge of the synchronization signal deviates from the normal time. The trigger signal output period may differ from the normal time. And if the trigger signal output period different from the normal time crosses the zero cross of the power supply voltage, even if the trigger signal output stops, the triac keeps on until the next zero cross, and the light quantity of the light source fluctuates greatly As a result, flicker may occur.

  Therefore, in the conventional example described in Patent Document 1, the rising interval of the synchronization signal is measured, and the trigger signal output is stopped when the interval deviates from the reference range (a range approximately equal to one cycle of the power supply voltage). To suppress flickering of the light source. In addition, the conventional example described in Patent Document 1 is configured to measure the interval even after the interval deviates from the reference range, and immediately restart the output of the trigger signal when the interval falls within the reference range. Yes.

JP 2013-20839 A

  By the way, when an instantaneous voltage drop (instantaneous voltage drop) of less than 1 second occurs in the AC power supply and the interval of the synchronization signal is out of the reference range, the trigger signal is output as in the conventional example described in Patent Document 1. Even if temporarily stopped, the flickering of the light source may not be resolved. Note that such an instantaneous voltage drop occurs, for example, when a plurality of loads (vacuum cleaners, air conditioners, microwave ovens, etc.) with relatively large power consumption operate at the same time, or when a solar cell or a fuel cell is turned on. It also occurs when power is used.

  That is, a noise preventing capacitor is connected between the input terminals of the lighting fixture and the dimmer, and these two capacitors are connected in series to the AC power supply. For this reason, the trigger signal may overlap with the zero cross due to the synchronization signal shift, and the triac may turn off in the vicinity of the peak value of the power supply voltage. In this case, the charge remains in the capacitor, and the voltage applied between the input terminals of the dimmer becomes lower than the power supply voltage by the voltage across the capacitor of the lighting fixture.

  Since the dimmer generates the synchronization signal based on the input voltage lower than the power supply voltage, the rise is delayed from the original synchronization signal (synchronization signal generated based on the power supply voltage). In addition, if the instantaneous voltage drop continues, the sync signal rises to the output of the trigger signal because the interval of the rise of the sync signal is almost equal to the power cycle despite the delay from the original rise of the sync signal. To resume. However, if the restarted trigger signal overlaps the zero crossing of the power supply voltage, the triac is turned off again near the peak value of the power supply voltage, and thus the above-described operation is repeated even after the recovery from the instantaneous voltage drop. Flicker may occur.

  The present invention has been made in view of the above problems, and an object thereof is to suppress the occurrence of flickering of a light source after recovery from an instantaneous voltage drop.

  The dimmer of the present invention detects a switching element connected in series with a lighting fixture between output terminals of a power source that outputs a sinusoidal AC voltage, and a period during which the AC voltage exceeds a predetermined threshold. A synchronization signal output unit for outputting a synchronization signal synchronized with the period; a trigger for determining a period for turning on the switching element from a rising edge of the synchronization signal; and for turning on the switching element in the on period A control unit that outputs a signal, and the control unit determines whether or not a rising interval of the synchronization signal falls within a predetermined reference range, and determines that the interval falls within the reference range The trigger signal is output, and the output of the trigger signal is stopped when it is determined that the interval is out of the reference range. Further, the output of the trigger signal is stopped after the output of the trigger signal is stopped. If it is determined that it falls within the reference range, the trigger signal output is resumed. When the number of times the interval is determined to fall within the reference range after restarting reaches a predetermined number of times, the trigger signal is output for at least one cycle. The output of the trigger signal is paused.

  The illuminating device of this invention has the said light control device and the lighting fixture connected in series between the output terminals of the said power supply with the said light control device, It is characterized by the above-mentioned.

  In this illuminating device, the luminaire preferably includes a solid light emitting element as a light source.

  Since the voltage applied to the dimmer becomes equal to the power supply voltage by stopping the output of the trigger signal, the dimmer and the lighting device of the present invention suppress the occurrence of flickering of the light source after the recovery from the instantaneous voltage drop. There is an effect that can be done.

It is a time chart for demonstrating operation | movement of embodiment of the light control device which concerns on this invention. It is the block diagram which shows embodiment of the illuminating device which concerns on this invention, and the circuit block diagram which shows embodiment of a light controller. It is a circuit block diagram of the lighting fixture in the same as the above. It is a time chart for demonstrating operation | movement of a prior art example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a dimmer according to the present invention and a lighting device including the dimmer and a lighting fixture will be described in detail with reference to the drawings.

  The dimmer 2 of the present embodiment is a DC trigger type dimmer similar to the conventional example described in Patent Document 1. Moreover, the illuminating device of this embodiment is comprised with the dimmer 2 and the lighting fixture 1 connected in series between the output terminals of AC power supply 3 with the dimmer 2 as shown in FIG.

  As shown in FIG. 3, the luminaire 1 includes a light source 10, a switch 11, a rectifier circuit 12, a smoothing circuit 13, a voltage dividing circuit 14, a dimming control unit 15, and a noise prevention capacitor C5. Prepare.

  The light source 10 includes a series circuit of a plurality (two in the illustrated example) of solid-state light emitting elements (for example, the light emitting diode 100) and a current limiting resistor R1. The switch 11 is a field effect transistor having a drain connected to the light source 10 and a source connected to the output terminal on the low potential side of the rectifier circuit 12.

  The rectifier circuit 12 is configured by a diode bridge, and one input terminal is connected to the positive electrode of the AC power source 3 and the other input terminal is connected to the dimmer 2. A noise preventing capacitor C5 is connected between the input terminals of the rectifier circuit 12. The smoothing circuit 13 includes a diode D1 and a smoothing capacitor C1. The diode D1 has an anode connected to the output terminal on the high potential side of the rectifier circuit 12, and a cathode connected to one end of the light source 10. The smoothing capacitor C1 has a high-potential side terminal connected to the cathode of the diode D1, and a low-potential side terminal connected to the low-potential side output terminal of the rectifier circuit 12.

  The voltage dividing circuit 14 includes a series circuit of two voltage dividing resistors R2 and R3, and is connected between the output terminals of the rectifier circuit 12. The voltage dividing circuit 14 then divides the power supply voltage (pulsating voltage) of the AC power supply 3 that has been full-wave rectified by the rectifying circuit 12 by the resistance ratio (voltage dividing ratio) of the voltage dividing resistors R2 and R3 (hereinafter referred to as the voltage dividing ratio). (Referred to as a detection voltage) is output to the dimming controller 15. The detected voltage is phase-controlled by the dimmer 2.

  The dimming control unit 15 converts the detection voltage into a square-wave pulse signal by comparing it with a reference voltage, and outputs the pulse signal to the gate terminal of the switch 11 to turn on the switch 11. That is, since the current flows through the light source 10 only when the switch 11 is on, the dimming control unit 15 uses the power supplied per unit time corresponding to the on-duty ratio of the phase-controlled detection voltage. The light source 10 can be dimmed by increasing or decreasing.

  On the other hand, as shown in FIG. 2, the dimmer 2 includes a switching element Q1, a power supply circuit 20, a synchronization signal output unit 21, a control unit 22, a pair of connection terminals 23 and 24, and the like. One end of the instrument 1 is connected, and the negative terminal of the AC power source 3 is connected to the other connection terminal 24.

  A switching element Q1 is connected to the connection terminals 23 and 24 through a noise prevention filter. This filter includes a capacitor C2 connected between the connection terminals 23 and 24, and an inductor L1 connected between one end of the capacitor C2 and the switching element Q1.

  The switching element Q1 is a self-holding semiconductor switching element, for example, a bidirectional three-terminal thyristor (triac), and one end is connected to the connection terminal 23 and the other end is connected to the connection terminal 24 via the inductor L1. . The gate terminal of the switching element Q1 is connected to the collector of the switching element Q2 made of an npn-type bipolar transistor. The switch element Q2 has an emitter connected to the ground and a base connected to the control unit 22.

  The power supply circuit 20 is an integrated circuit in which a switching element and a control circuit that controls switching of the switching element are integrated, and an input voltage (DC voltage) that has been half-wave rectified by a diode D2 and smoothed by a smoothing capacitor C3. The output is stabilized to a desired constant voltage.

  An inductor L2, a capacitor C4, and a diode D4 are connected to the output terminal of the power supply circuit 20, and a step-up / step-down chopper circuit is configured by the switching element, the inductor L2, the capacitor C4, and the diode D4 of the integrated circuit. Inductor L2 has one end connected to the output end of power supply circuit 20, and the other end connected to the high potential side terminal of capacitor C4 made of an electrolytic capacitor. The capacitor C4 has a high potential side terminal connected to the low potential side terminal of the smoothing capacitor C3 and a low potential side terminal connected to the ground. The diode D4 has an anode connected to the ground and a cathode connected to the output terminal of the power supply circuit 20. That is, the step-up / step-down chopper circuit charges the capacitor C4 through the inductor L2, and supplies the charging voltage of the capacitor C4 to the control unit 22 as an operating voltage (control voltage).

  A power supply voltage (AC voltage) applied between the connection terminals 23 and 24 is input to the synchronization signal output unit 21 after being half-wave rectified by the diode D5. The synchronization signal output unit 21 compares the input voltage (half-wave rectified power supply voltage) with a predetermined threshold value Vf, and becomes high level when the input voltage exceeds the threshold value Vf. A synchronization signal that is at a low level is generated when is below the threshold value Vf (see FIG. 1). Since the power supply voltage half-wave rectified by the diode D5 is input to the synchronization signal output unit 21, 1 is provided for every positive half cycle of the cycle of the power supply voltage of the AC power supply 3 (hereinafter referred to as the power supply cycle). A synchronization signal is generated and output to the control unit 22 each time.

  Although not shown, the voltage divided by the potentiometer is input to the control unit 22. This potentiometer is configured such that the sliding contact slides in response to, for example, rotation of a dial type operation knob. That is, the voltage input to the control unit 22 is a voltage that is divided by the potentiometer at a voltage dividing ratio corresponding to the operation position of the operation knob. Therefore, the control unit 22 can read the operation position of the operation knob, that is, the dimming level from the voltage. Then, the control unit 22 generates a trigger signal for turning on the switching element Q1 based on the read dimming level and the synchronization signal output from the synchronization signal output unit 21.

  That is, the control unit 22 determines a period (on period) during which the switching element Q1 is turned on starting from the rising edge of the synchronization signal, and generates a square-wave trigger signal that becomes a high level during the on period, thereby generating the switching element Q2. Output to base. The switch element Q2 is turned on when the trigger signal is output. When the switching element Q2 is turned on, the switching element Q1 is turned on because the gate terminal of the switching element Q1 is biased to a negative potential by the charging voltage of the capacitor C4. When the control unit 22 stops the trigger signal, the switch element Q2 is turned off, and the gate terminal of the switching element Q1 is not biased to a negative potential. However, since the switching element Q1 maintains a conductive state while a holding current exceeding a certain level flows, the power supply voltage of the AC power supply 3 is applied to the lighting fixture 1 for a while after the trigger signal is stopped (falling). to continue. When the power supply voltage of the AC power supply 3 crosses zero, the holding current flowing through the switching element Q1 becomes below a certain level, and the switching element Q1 is turned off.

  Here, the ON period varies depending on the time (delay time) from the rising edge of the synchronization signal to the rising edge of the trigger signal. Therefore, the control unit 22 is configured to shorten the delay time and extend the ON period as the dimming level is higher (the light amount of the light source 10 is larger). In addition, since the control unit 22 turns on the switching element Q1 once every half cycle of the power supply voltage, two delay times T1, T1 + (1/2) × T0 (T0 is a power cycle) corresponding to the ON period. ) A trigger signal is output every time (see FIG. 1). That is, the control unit 22 is configured to generate and output two trigger signals from one synchronization signal for each power cycle T0.

  Further, the control unit 22 monitors the rising interval of the synchronization signal output from the synchronization signal output unit 21. The interval between rising edges of the synchronizing signal is the time required from the rising edge of the previous synchronizing signal to the rising edge of the current synchronizing signal. If an abnormality such as a momentary power failure does not occur, the synchronization signal rising interval (hereinafter referred to as the synchronization interval) should coincide with the power cycle T0. Therefore, the control unit 22 determines whether or not the synchronization interval falls within the range (reference range) of T0 ± ΔT0. If it is determined that the synchronization interval falls within the range, the delay time T1, T1 + (1 / 2) A trigger signal is output every × T0. If the control unit 22 determines that the synchronization interval does not fall within the reference range, the control unit 22 stops generating and outputting the trigger signal. When the power supply frequency is 50 Hz, the power supply period T0 is 20 milliseconds, so it is preferable that the reference range is about 20 milliseconds ± 0.8 milliseconds.

  Next, the operation of the dimmer 2 of this embodiment will be described in detail with reference to the time chart of FIG. The synchronization signal output unit 21 generates a synchronization signal SY 1 from the power supply voltage applied between the connection terminals 23 and 24 and outputs the synchronization signal SY 1 to the control unit 22. The control unit 22 determines the ON period (delay time T1, T1 + (1/2) × T0) corresponding to the dimming level, and outputs the trigger signals TG1 and TG2. Further, the control unit 22 stops (falls) the trigger signals TG1 and TG2 when the on period corresponding to the dimming level has elapsed from the start (rise) of the trigger signals TG1 and TG2. Since the switch element Q2 is turned off when the trigger signals TG1 and TG2 are stopped, the switching element Q1 is turned off when the power supply voltage is zero-crossed. Therefore, the switching element Q1 is turned on only for a period (on period) slightly longer than the period during which the trigger signals TG1 and TG2 are output, and the power supply voltage is applied from the AC power source 3 to the lighting fixture 1 only during this on period. The

  The dimming control unit 15 of the luminaire 1 compares the detection voltage obtained by dividing the power supply voltage phase-controlled by the dimmer 2 by the voltage dividing circuit 14 with the reference voltage, so that the detection voltage exceeds the reference voltage. A square-wave pulse signal that is at a high level during generation is generated. Then, the switch 11 is turned on by applying this pulse signal to the gate terminal, and the light source 10 is dimmed by expanding and contracting the ON period of the switch 11 corresponding to the dimming level.

  Here, it is assumed that an instantaneous voltage drop occurs in the power supply voltage immediately after the trigger signal TG2 is stopped as shown in FIG. When an instantaneous voltage drop occurs, the timing at which the voltage applied between the connection terminals 23 and 24 (the input voltage of the dimmer 2) exceeds the threshold value Vf is later than usual. The timing to output (start up) SY2 is also delayed. When the synchronization interval from the previous rise of the synchronization signal SY1 to the rise of the current synchronization signal SY2 is outside the reference range T0 + ΔT0, the controller 22 of the dimmer 2 corresponds to the synchronization signal SY2. Trigger signals TG3 and TG4 are not output (stopped). If the trigger signal is not output, the switching element Q1 is not turned on, and the power source voltage is not applied to the luminaire 1, so the light source 10 is turned off. However, if the lighting fixture 1 averages a plurality of trigger signals to determine the dimming level, it is possible to prevent the light output from changing even if the trigger signal is stopped once.

  If the instantaneous voltage drop continues in the next power cycle, the synchronization interval between the previous synchronization signal SY2 and the current synchronization signal SY3 substantially matches the power cycle T0. Therefore, the control unit 22 determines that the synchronization interval is within the reference range, and outputs trigger signals TG5 and TG6. Similarly, if the instantaneous voltage drop continues in the next power cycle, the synchronization interval between the previous synchronization signal SY3 and the current synchronization signal SY4 substantially matches the power cycle T0. It is determined that it is within the range, and trigger signals TG7 and TG8 are output.

  Here, as shown in FIG. 4, when the trigger signal TG8 corresponding to the previous synchronization signal SY4 overlaps the zero cross of the input voltage (power supply voltage), the triac is turned off near the peak value of the power supply voltage as described in the prior art. There is a case. In this case, charged charges remain in the capacitor C5 of the lighting fixture 1 and the capacitor C2 of the dimmer 2, and the input voltage (see the solid line in FIG. 4) of the dimmer 2 is lower than the power supply voltage (see the broken line in FIG. 4). Therefore, the situation will be the same as when an instantaneous voltage drop occurs. As a result, the possibility of flickering in the light source 10 increases as in the conventional example.

  On the other hand, the controller 22 in the present embodiment restarts outputting the trigger signals TG5 and TG6, and the number of times that the synchronization interval is determined to be within the reference range does not reach a predetermined number (for example, 2 times). Then, the output of the trigger signals TG9 and TG10 is stopped. That is, the synchronization interval between the synchronization signal SY3 and the synchronization signal SY4 is within the reference range, but if the synchronization interval between the synchronization signal SY4 and the synchronization signal SY5 is out of the reference range, the control unit 22 changes the synchronization signal SY5 to the synchronization signal SY5. Stops the output of the corresponding trigger signals TG9 and TG10.

  Further, as shown in FIG. 1, the control unit 22 determines that the synchronization interval between the synchronization signals SY3 and SY4 and the synchronization interval between the synchronization signals SY4 and SY5 are both within the reference range (the number of times reaches 2). For example, the output of the trigger signals TG11 and TG12 corresponding to the next synchronization signal SY6 is stopped (paused). Then, after stopping the output of the trigger signals TG11 and TG12, the control unit 22 resumes the output from the trigger signals TG13 and TG14 corresponding to the next synchronization signal SY7.

  Thus, since the light source 10 is turned off when the control unit 22 stops outputting the trigger signals TG11 and TG12, the charge of the capacitor C5 of the luminaire 1 is discharged and the input voltage of the dimmer 2 becomes the power supply voltage. Is equal to As a result, the occurrence of flickering of the light source 10 due to a decrease in the input voltage of the dimmer 2 can be suppressed.

  As described above, the dimmer 2 of the present embodiment includes the switching element Q1 connected in series with the lighting fixture 1 between the output terminals of the power source 3 that outputs a sine wave AC voltage, and the AC voltage is a predetermined threshold value. A synchronization signal output unit 21 that detects a period exceeding Vf and outputs a synchronization signal synchronized with the period is provided. Further, the dimmer 2 of the present embodiment determines a period during which the switching element Q1 is turned on starting from the rising edge of the synchronization signal, and outputs a trigger signal for turning on the switching element Q1 during the on period. Is provided. Further, the control unit 22 determines whether or not the rising interval of the synchronization signal falls within a predetermined reference range, and outputs a trigger signal when determining that the interval falls within the reference range. Further, the control unit 22 stops outputting the trigger signal when it is determined that the interval is out of the reference range. Further, when the control unit 22 determines that the interval falls within the reference range after stopping the output of the trigger signal, the control unit 22 restarts the output of the trigger signal. Then, the control unit 22 is configured to pause the output of the trigger signal for at least one cycle of the synchronization signal when the number of times that the interval is determined to be within the reference range after restarting reaches a predetermined number.

  Since the dimmer 2 of the present embodiment is configured as described above, the input voltage applied between the connection terminals 23 and 24 becomes equal to the power supply voltage by pausing the output of the trigger signal. The occurrence of flickering of the light source 10 after returning from the voltage drop can be suppressed.

  In the present embodiment, the number of times for determining whether or not to stop the output of the trigger signal is two times, but it may be three or more times. Also, the number of pauses is not limited to one and may be two or more.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 2 Dimmer 3 AC power supply (power supply)
21 Sync signal output
22 Control unit

Claims (3)

A switching element connected in series with a lighting fixture between output terminals of a power source that outputs an AC voltage of a sine wave, and a synchronization signal that detects a period in which the AC voltage exceeds a predetermined threshold and is synchronized with the period And a control unit that determines a period during which the switching element is turned on starting from the rising edge of the synchronization signal and outputs a trigger signal for turning on the switching element during the on period. Prepared,
The control unit determines whether or not a rising interval of the synchronization signal falls within a predetermined reference range, and outputs the trigger signal when determining that the interval falls within the reference range. Stops the output of the trigger signal when it is determined that is outside the reference range, and resumes the output of the trigger signal when it is determined that the interval falls within the reference range after the trigger signal output is stopped. When the number of times that the interval is determined to be within the reference range after restarting reaches a predetermined number, the output of the trigger signal for at least one period of the synchronization signal is paused. Dimmer.   An illumination device comprising: the dimmer according to claim 1; and a lighting fixture connected in series between output terminals of the power source together with the dimmer.   The lighting apparatus according to claim 2, wherein the lighting fixture includes a solid-state light emitting element as a light source.

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