JP4687264B2 - Discharge lamp lighting device, lighting fixture and lighting system - Google Patents

Description

  The present invention relates to a discharge lamp lighting device for dimming a high-pressure discharge lamp, a lighting fixture using the same, and a lighting system.

  FIG. 12 shows the configuration of a conventional high pressure discharge lamp lighting device. Reference numeral 1 denotes a step-down chopper circuit, 2 a control circuit thereof, 3 a polarity inversion circuit, 4 an igniter, and 5 a drive circuit. The output voltage of the DC power source E is stepped down by the step-down chopper circuit 1, and the DC output voltage Vc1 is converted to AC by the polarity inversion circuit 3, whereby the high-pressure discharge lamp La is turned on by AC rectangular waves. The drive circuit 5 controls the switching elements Q2 to Q5 of the polarity inversion circuit 3, and at the time of starting, the switching elements Q2 and Q3 are alternately turned on and off at a high frequency so as to resonate the LC resonance circuit of the igniter 4, thereby releasing the high voltage. The electric lamp La is started, and at the time of lighting, the pair of switching elements Q2 and Q5 and the pair of switching elements Q3 and Q4 are alternately turned on so that a low-frequency rectangular wave voltage is obtained between the terminals a and b. The control circuit 2 feeds back the output voltage Vc1 of the step-down chopper circuit 1 and outputs the ON duty of the switching element Q1 according to the value. When the dimming signal LS for reducing the output power is input, the control circuit 2 performs control so as to sandwich the ON duty of the switching element Q1, so that the output voltage Vc1 of the step-down chopper circuit 1 is reduced and the lamp current is reduced. By being reduced, the high-pressure discharge lamp La can be dimmed.

  As described above, when dimming a high-pressure discharge lamp, light is generally dimmed by controlling lamp current flowing through the high-pressure discharge lamp and reducing lamp power supplied to the high-pressure discharge lamp. However, when the high pressure discharge lamp is dimmed in this way, the lamp current decreases, the temperature of the electrode decreases, and it becomes difficult to emit thermoelectrons. There is a possibility of disappearing.

As a conventional example that solves such a problem, there is JP-A-2002-164191. FIG. 13 shows the operation of this conventional example. The circuit configuration is the same as in FIG. In this conventional example, at least when the output power changes from the fully lit state to the dimming lit state, the polarity reversing operation of the polarity reversing circuit is temporarily stopped, and the lighting at the time of polarity reversal is stopped by direct current lighting. It is to prevent.
JP 2002-164191 A

  However, in this conventional example, when returning from DC lighting to rectangular wave lighting, the electrode temperature on one side is not sufficiently warmed, so that electrons are sufficiently discharged from the cooled electrode at the first polarity reversal. However, there is a problem that a re-ignition voltage is generated and there is a possibility that it may disappear. In particular, there is a problem that if the light is dimmed when the lamp voltage rises at the end of the life of the high-pressure discharge lamp, the possibility of going off increases.

  The present invention has been made in view of these points, and an object of the present invention is to provide a discharge lamp lighting device that does not easily turn off even when the high-pressure discharge lamp is dimmed.

According to the first aspect of the present invention, in order to solve the above-mentioned problem, as shown in FIG. 1, the power converter 1 that converts the output of the DC power source E to power and the output power of the power converter 1 are controlled. A high-pressure discharge lamp comprising a control circuit unit 2 for dimming the high-pressure discharge lamp La according to the dimming signal LS, and a polarity inversion unit 3 for converting the output power of the power conversion unit 1 into low-frequency rectangular wave power In the high pressure discharge lamp lighting device for lighting La in a rectangular wave, as shown in FIG. 3 or FIG. 4 , at least a first period including a period in which output power changes from full lighting to dimming lighting is DC lighting, period and outputs a power greater than the output power that is set in advance in accordance with at least the dimming signal LS while being maintained second period dc lighting after the elapse, after the second period of time of In the third period, the polarity inversion operation is restored, and in the third period, The rectangular wave power is controlled to be unbalanced depending on the polarity, and the rectangular wave power that is unbalanced in the third period is controlled so as to increase the output power of the polarity opposite to that in the first and second periods. Then, after the third period has elapsed, the rectangular wave power is returned to equilibrium .

  According to the second aspect of the present invention, as shown in FIGS. 6 and 7, the output voltage of the power converter is detected at least when the output power changes from full lighting to dimming lighting, and the output voltage is predetermined. When the value is exceeded, the transition of the output power is stopped, and when the output voltage falls below a predetermined value, the transition of the output power is resumed.

  According to the first aspect of the invention, at least a first period including a period in which the output power changes from full lighting to dimming lighting is DC lighting, and a second period after the first period has elapsed is DC lighting. In this case, the output power higher than the preset output power is output in accordance with the dimming signal while maintaining the voltage, and the polarity inversion operation is restored after the second period has elapsed. Dimming can be prevented stably by preventing the lights from dimming.

  In the second aspect of the invention, when the output voltage of the power conversion unit exceeds a predetermined value, the transition of the output power that shifts from full lighting to dimming lighting is stopped. Dimming and lighting can be stably prevented.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described. Embodiments 2 and 3 to be described later correspond to claim 1, embodiments 5 and 6 correspond to claims 2 and 3, respectively, and other embodiments. Is described as a premise configuration or an additional configuration.
(Embodiment 1)
FIG. 1 shows a circuit configuration of Embodiment 1 of the present invention. E is a DC power supply, and is constituted by, for example, a DC power supply circuit (which may include a step-up chopper circuit) that rectifies and smoothes a commercial AC power supply. The output voltage of the DC power source E is converted into electric power by the step-down chopper circuit 1. The step-down chopper circuit 1 includes a switching element Q1, a diode D, an inductor L, and a smoothing capacitor C1, and outputs a DC voltage Vc1 obtained by stepping down the input DC voltage by causing the control circuit 2 to switch the switching element Q1 at a high frequency. . Here, by changing the ON duty of the switching element Q1, the output voltage Vc1 of the step-down chopper circuit 1 changes, and the high-pressure discharge lamp La can be dimmed.

  The output of the step-down chopper circuit 1 is connected to the polarity inversion circuit 3 and is switched by the control circuit 2 when the switching elements Q2 and Q5 are turned on and the switching elements Q3 and Q4 are turned off, and the switching elements Q2 and Q5 are turned off. The elements Q3 and Q4 are turned on alternately at a low frequency, whereby the high-pressure discharge lamp La is lit with a rectangular wave with a low-frequency AC voltage.

  Since the operation of the igniter 4 is general, detailed description thereof is omitted. For example, the switching elements Q2 and Q3 are alternately turned on / off at a high frequency of the resonance frequency of the LC resonance circuit (or an integer multiple or a fraction of an integer) By turning it off, a high-frequency high voltage is applied to both ends of the high-pressure discharge lamp La to start it.

  In this embodiment, a microcomputer 2a (M37540) and a control integrated circuit 2b (analog master μPC5020GT) are used as the control circuit 2. The triangular wave current flowing in the step-down chopper circuit 1 is converted into a voltage by the detection resistor Rd and input to the control integrated circuit 2b. On the other hand, the microcomputer 2a detects the output voltage Vc1 and the dimming signal LS of the step-down chopper circuit 1, and outputs a duty signal corresponding to each. The Duty signal is smoothed by a filter circuit including a resistor Rf and a capacitor Cf, and is input to the control integrated circuit 2b as an Ipref signal that determines the ON duty of the switching element Q1 of the step-down chopper circuit 1. When the Ipref signal and the signal converted by the detection resistor Rd are at the same level, the control integrated circuit 2b outputs a signal to turn off the switching element Q1 of the step-down chopper circuit 1. Therefore, by continuously increasing or decreasing the voltage of the Ipref signal, the current flowing through the step-down chopper circuit 1 can be controlled, and as a result, the power supplied to the high-pressure discharge lamp La can be controlled.

  Here, when the dimming signal LS is input, the ON duty of the switching element Q1 of the step-down chopper circuit 1 is variably controlled, and after reaching a predetermined output power specified by the dimming signal LS, the discharge is stabilized. As shown in FIG. 2, the switching elements Q2 and Q5 of the polarity inverting circuit 3 operate so as to hold the Q3 and Q4 off states, and the DC lighting is performed during the dimming transient.

  When the discharge is stabilized, the polarity inversion circuit 3 is operated again, but immediately before that, the output voltage Vc1 of the step-down chopper circuit 1 is increased to increase the output power and increase the amount of electrons emitted from the electrodes. As a result, the temperature of the electrode on the side receiving electrons during DC lighting is warmed, and the polarity inversion circuit 3 starts to operate again, so that it becomes easy to emit electrons when switched to rectangular wave lighting.

  In this way, the operation of the polarity inversion circuit 3 is stopped when the power changes from full lighting to dimming lighting, and the output power is increased immediately before switching to rectangular wave lighting by transiently DC lighting and switching to rectangular wave lighting. The electric light La can be dimmed stably.

  According to the study by the present inventors, the period during which the output power is increased immediately before switching to the rectangular wave lighting is at least 10% of the half cycle of the rectangular wave, or the output power to be increased is at the time of full lighting. If it is 70% or more, it is effective.

(Embodiment 2)
FIG. 3 shows the operation of the second embodiment of the present invention. The present embodiment is an example in which the first embodiment is further improved. The difference from the first embodiment is that when switching from direct current lighting to rectangular wave lighting, the current of the rectangular wave is unbalanced by polarity only for a predetermined period. It is. At this time, there is a first electrode on the side from which electrons were emitted during direct current lighting and a second electrode on the side from which electrons were received, but electrons emitted from the second electrode are emitted from the first electrode only for a predetermined period. Control to be larger than the electron to be. After a predetermined period, the current is returned to equilibrium.

  In this way, during the predetermined period after returning from the polarity reversal operation, the temperature decreases during direct current lighting by controlling to increase the current of the opposite polarity to the current polarity during the direct current lighting period. The electrode that has been heated is sufficiently warmed, and light can be adjusted stably.

(Embodiment 3)
FIG. 4 shows the operation of the third embodiment of the present invention. This embodiment is another example in which the first embodiment is further improved. The difference from the first embodiment is that when switching from direct current lighting to rectangular wave lighting, the rectangular wave period is made unbalanced by polarity only for a predetermined period. It is a point. At this time, there is a first electrode that emits electrons during DC lighting and a second electrode that receives electrons, but the period during which electrons are emitted from the second electrode only during a predetermined period. The period is controlled so as to be longer than the period during which electrons are emitted. After a predetermined period, the rectangular wave period is returned to equilibrium.

  In this way, the temperature decreases during DC lighting by controlling the polarity period opposite to the polarity of the current during the DC lighting for a predetermined period after returning from the polarity inversion operation. The electrode that has been heated is sufficiently warmed, and light can be adjusted stably.

(Embodiment 4)
FIG. 5 shows the operation of the fourth embodiment of the present invention. The present embodiment is another example in which the first embodiment is further improved. The difference from the first embodiment is that the polarity of the direct current lighting at the time of the dimming transition is switched at random. Specifically, in the first embodiment, the switching elements Q2 and Q5 are always turned on and the switches Q3 and Q4 are kept off at the time of DC lighting. If the switching elements Q3 and Q4 are turned on when the signal LS is input, the switching elements Q3 and Q4 maintain the on state and shift to DC lighting, and if the switching elements Q2 and Q5 are on, Control is performed so that the switching elements Q2 and Q5 are kept in the on-state and shifted to DC lighting.

  By controlling in this way, the degree of electrode wear due to DC lighting can be made uniform, and deterioration of the life of the discharge lamp can be prevented. Note that the control in this embodiment is also effective in the second and third embodiments.

(Embodiment 5)
FIG. 6 shows a flowchart of control according to the fifth embodiment of the present invention. The circuit diagram is the same as FIG. When the dimming signal LS is input, the Ipref signal is reduced and the step-down chopper circuit 1 starts the dimming operation. A voltage Vc1 ′ obtained by dividing the output voltage Vc1 of the step-down chopper circuit 1 by resistors R1 and R2 is input to the microcomputer 2a. The detection voltage Vc1 ′ is compared with the predetermined value Vth inside the microcomputer 2a. If Vc1 ′> Vth, the current dimming level is compared with the target level based on the dimming signal. If the current dimming level has reached the target level, the process proceeds to the next process, and if not, the dimming operation is continued. If Vc1 ′> Vth, the dimming operation is stopped and control is performed so as to maintain the current dimming level.

  By controlling in this way, since the change in the output power is stopped when the re-ignition voltage is generated at the time of the change in the output power that shifts to dimming lighting, the possibility of going off can be reduced. Note that the control in the present embodiment is also effective during the dimming transition in the first to third embodiments.

(Embodiment 6)
FIG. 7 shows a flowchart of control according to the sixth embodiment of the present invention. The circuit diagram is the same as FIG. When the dimming signal LS is input, the Ipref signal is reduced and the step-down chopper circuit 1 starts the dimming operation. A voltage Vc1 ′ obtained by dividing the output voltage Vc1 of the step-down chopper circuit 1 by resistors R1 and R2 is input to the microcomputer 2a. The detection voltage Vc1 ′ is compared with the predetermined value Vth inside the microcomputer 2a. If Vc1 ′> Vth, the counter value COUNT in the microcomputer 2a is incremented by one, and the counter value COUNT has exceeded the predetermined number n. Judge whether. If the value COUNT of the counter exceeds the predetermined number n, the dimming transition operation is stopped and transition to full lighting is performed. If the counter does not exceed the predetermined number n, the dimming transition operation is stopped and control is performed so as to maintain the current dimming level. If Vc1 ′> Vth, the current dimming level is compared with the target level based on the dimming signal. If the current dimming level has reached the target level, control proceeds to the next process, and if not, control is performed to continue the dimming operation.

  By controlling in this way, the dimming transition operation is stopped when the re-ignition voltage is generated at the time of the change of the output power that shifts to the dimming lighting, so that the possibility of extinction can be reduced. Furthermore, when the number of times of re-ignition voltage exceeds a predetermined number, the lighting is shifted to full lighting, so that it can be prevented from disappearing at the end of the life of the discharge lamp. The control in the present embodiment is also effective at the time of dimming transition in the first to third embodiments.

  When the counter value COUNT exceeds the predetermined number n, display means may be provided for notifying the user that the discharge lamp is at the end of its life.

(Embodiment 7)
FIG. 8 shows the operation of the seventh embodiment of the present invention. The circuit diagram is the same as FIG. In the present embodiment, when dimming the discharge lamp, the portion immediately before the polarity inversion is maintained at the level at the time of full lighting, and the dimming is performed by reducing the power of only the first half of each rectangular wave. It is an example. By controlling in this way, it is possible to prevent disappearance during dimming. The control in this embodiment is also effective during the light control in the first to sixth embodiments.

(Embodiment 8)
FIG. 9 shows the operation of the eighth embodiment of the present invention. The circuit diagram is the same as FIG. The present embodiment is an example in which the seventh embodiment is further improved, and is an example in which the period for reducing the current in each rectangular wave is changed according to the degree of dimming. The deeper the dimming degree, the longer the current reduction period and the shorter the period during which all lighting levels are maintained. By controlling in this way, it is possible to prevent disappearance during dimming. The control in this embodiment is also effective during the light control in the first to sixth embodiments.

(Embodiment 9)
FIG. 10 shows an embodiment 9 of the present invention. The circuit diagram is the same as FIG. The present embodiment is another example in which the seventh embodiment is further improved, and the current value immediately before the polarity inversion is changed according to the degree of dimming. Control is performed so that the current value immediately before the polarity inversion is increased as the degree of dimming is deeper. By controlling in this way, it is possible to prevent disappearance during dimming. The control in this embodiment is also effective during the light control in the first to sixth embodiments.

(Embodiment 10)
FIG. 11 shows a structural example of a lighting fixture using the discharge lamp lighting device of the present invention. (A), (b) is an example applied to a spotlight, (c) is an example applied to a downlight. In the figure, 11 is an electronic ballast storing a circuit of a lighting device, and 12 is a high pressure discharge lamp. The lamp body 13 is a wiring. You may construct | assemble an illumination system by combining these lighting fixtures with the light control device which outputs the light control signal LS according to the output of an illumination intensity sensor, a human sensitive sensor, or a manual light control operation part.

It is a circuit diagram which shows the structure of Embodiment 1 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 1 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 2 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 3 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 4 of this invention. It is a flowchart which shows operation | movement of Embodiment 5 of this invention. It is a flowchart which shows operation | movement of Embodiment 6 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 7 of this invention. It is a wave form diagram which shows the operation | movement of Embodiment 8 of this invention. It is a wave form diagram which shows operation | movement of Embodiment 9 of this invention. It is a perspective view of the lighting fixture using the discharge lamp lighting device of this invention. It is a circuit diagram which shows the structure of a prior art example. It is a wave form diagram which shows operation | movement of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Step-down chopper circuit 2 Control circuit 3 Polarity inversion circuit 4 Igniter La High pressure discharge lamp

Claims (5)

A power conversion unit for converting the output of the DC power source, a control circuit unit for controlling the output power of the power conversion unit and dimming the high-pressure discharge lamp according to the dimming signal, and the output power of the power conversion unit for low frequency In the high-pressure discharge lamp lighting device that includes a polarity reversing unit that converts to rectangular wave power and that illuminates the high-pressure discharge lamp in a rectangular wave, at least a first period including a period in which the output power changes from full lighting to dimming lighting During the second period after the first period has elapsed after the first period has elapsed, the second period is the period when the output power that is set in advance according to the dimming signal is output while maintaining the DC lighting. In the third period after the elapse of time, the polarity inversion operation is restored, and in the third period, the rectangular wave power is controlled to be unbalanced depending on the polarity, and the rectangular wave power is unbalanced in the third period. Of the polarity opposite to the first and second periods. Controlled so as to increase the power, after the expiration of a third period, the discharge lamp lighting device and returning the rectangular wave power equilibrium. A power conversion unit for converting the output of the DC power source, a control circuit unit for controlling the output power of the power conversion unit and dimming the high-pressure discharge lamp according to the dimming signal, and the output power of the power conversion unit for low frequency In a high-pressure discharge lamp lighting device having a polarity reversing unit that converts to rectangular wave power and lighting a high-pressure discharge lamp in a rectangular wave, at least when the output power changes from full lighting to dimming lighting, the output of the power conversion unit A discharge lamp lighting device characterized by detecting a voltage, stopping the transition of output power when the output voltage exceeds a predetermined value, and restarting the transition of output power when the output voltage falls below a predetermined value. 3. The discharge lamp lighting device according to claim 2, wherein the number of times the output voltage of the power converter exceeds a predetermined value is counted, and when the number exceeds the predetermined number, the shift to dimming lighting is prohibited or displayed. A discharge lamp lighting device characterized by that. A lighting fixture comprising the discharge lamp lighting device according to any one of claims 1 to 3, wherein the high pressure discharge lamp is dimmed with the discharge lamp lighting device. The lighting system comprised from the lighting fixture of Claim 4 , and the dimmer which gives a light control signal to this lighting fixture.

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