JP4214785B2 - High pressure discharge lamp lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device that performs high-frequency lighting of a high-pressure discharge lamp.
[0002]
[Prior art]
When a high-pressure discharge lamp (hereinafter referred to as a “lamp”) is lit at a high frequency, the discharge arc is bent due to the interference between the traveling wave of the sound wave generated in the lamp and the reflected wave, causing so-called extinction or lamp destruction. It is known that the phenomenon is likely to occur. In particular, when high-frequency lighting of 1 kHz or higher is selected, a frequency band in which an acoustic resonance phenomenon does not occur (hereinafter referred to as “non-resonant frequency band”) is selected for lighting. However, it is known that this non-resonant frequency band varies depending on lamps and moves due to disturbances such as secular change and installation direction.
[0003]
Therefore, the conventional high pressure discharge lamp lighting device includes means for avoiding the acoustic resonance phenomenon by correcting the frequency, and means for adjusting the lamp voltage that has changed due to frequency shift (for example, Patent Document 1).
[0004]
[Patent Document 1]
US Pat. No. 5,623,187
[Problems to be solved by the invention]
The conventional high pressure discharge lamp lighting device is configured as described above, and has the following problems.
[0006]
The adjustment of the lamp power affects the lamp voltage and the lamp current because the output of the DC power supply is adjusted. Further, the correction of the frequency has been performed based on the detected values of the lamp voltage and the lamp current. The correction of the frequency and the adjustment of the lamp power are not clearly separated in time, and the lamp power may be adjusted while the frequency is being corrected. As a result, the lamp voltage or lamp current affected by the output adjustment of the DC power supply is detected, and the frequency cannot be corrected correctly, and the acoustic resonance phenomenon cannot be avoided.
[0007]
The present invention has been made to solve the above-described problems, and provides a high-pressure discharge lamp lighting device capable of reliably performing an operation of correcting a frequency for avoiding an acoustic resonance phenomenon and an operation of adjusting lamp power. The purpose is to do.
[0008]
[Means for Solving the Problems]
A high pressure discharge lamp lighting device according to the present invention includes a high pressure discharge lamp, tube voltage detecting means for detecting a tube voltage of the high pressure discharge lamp, a high frequency power supply circuit for supplying AC power of 1 kHz or more to the high pressure discharge lamp, and a high frequency A control circuit that controls the output power and output frequency of the power supply circuit and a power detection circuit that detects the power applied to the high-pressure discharge lamp are provided, and the control circuit does not include an acoustic resonance frequency unique to the high-pressure discharge lamp. In addition to controlling the output frequency in the frequency band, the output voltage of the DC power supply is controlled so that the value detected from the power detection circuit falls within a predetermined range, and in executing these two controls, the two controls are simultaneously performed. The frequency control and the output voltage control are alternately repeated without being executed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a block configuration diagram showing a circuit configuration of a high pressure discharge lamp lighting device according to Embodiment 1 of the present invention.
In the figure, a high pressure discharge lamp lighting device includes a DC power supply 1 having a variable output voltage, an inverter circuit 2 composed of MOSFETs 3 and 4, a control circuit 5 for controlling the output voltage of the DC power supply 1 and the frequency of the inverter circuit 2, a choke. A load circuit 6 including a coil 7, a DC cut capacitor 8 and a starting circuit 9 and a lamp 10 are included.
In addition, a lamp voltage detection circuit 11, a timer 12, a detection resistor 13, and a lamp power detection circuit 14 are connected to the control circuit 5.
[0010]
Next, the operation of the high pressure discharge lamp lighting device will be described.
The MOSFETs 3 and 4 are alternately turned ON / OFF at several tens of kHz by the control circuit 5 to convert the output of the direct current 1 into a high frequency. The electric power converted into the high frequency is reduced by the choke coil 7 and the lamp 10 is turned on by the current resonance action with the DC cut capacitor 8. The starting circuit 9 is for inducing a discharge in the lamp 10 and applies a high voltage pulse of several kV between the lamp electrodes when the lighting operation starts. Then, the insulation between the lamp electrodes is broken, and when the discharge starts, it is cut off.
[0011]
Based on the lamp voltage detected by the lamp voltage detection circuit 11, the control circuit 5 determines the lighting frequency and drives the inverter circuit 2. The lighting frequency is calculated and updated every interval set in the timer 12.
The lamp power detection circuit 14 detects the power consumption of the lamp 10 based on the voltage generated in the detection resistor 13 inserted between the inverter circuit 2 and the ground. In the control circuit 5, the output voltage of the DC power supply 1 is controlled so that the power consumption of the lamp 10 detected by the lamp power detection circuit 14 falls within a predetermined range.
[0012]
FIG. 2 shows the relationship between the frequency control and the output voltage control of the high pressure discharge lamp lighting device according to the present embodiment.
In the figure, the frequency control of the inverter circuit 2 and the output voltage control of the DC power supply 1 are repeatedly executed alternately at predetermined intervals. Assuming that the intervals are A and B, A and B have the same value.
[0013]
FIG. 3 is an example of a flowchart for realizing a sequence in which the frequency control and the output voltage control shown in FIG. 2 are repeated at equal intervals.
The flow operation will be described with reference to the drawings.
[0014]
The lighting operation starts (step S100), and frequency control is performed (step S102). At the end of the frequency control, the timer tx is set (Tx = X) and started (step S103). Simultaneously with the start of the timer tx, the lamp voltage detection circuit 11 samples the lamp voltage and detects the presence or absence of instability during discharge (step S104). If instability is detected, the control circuit 5 stops the inverter circuit 2 and turns off the lamp 10 (step S107). The operation of detecting the presence or absence of instability is continued until the timer tx ends (Tx = 0) (steps S108 and S109).
[0015]
Next, the lamp power detection circuit 14 detects the lamp power and determines whether it is within a predetermined range (step S110). If it is outside the predetermined range, the output of the DC power source 1 is adjusted by the control circuit 5 (step S111), and the timer ty is set (Ty = Y) and started (step S112).
On the other hand, if the lamp power is within the predetermined range in step S110, the timer ty is set and started without adjusting the output of the DC power source 1 (not through step S111) (step S112). When the timer ty ends (Ty = 0) (steps S113 and S114), the process returns to immediately before the frequency control (step S102), and the above series of operations is repeated.
[0016]
As described above, the lamp voltage affected by the output adjustment of the DC power supply as a result of executing the sequence of alternately repeating the frequency control and the output voltage control so that the two controls are not executed simultaneously. And the lamp current are not detected, the frequency is corrected correctly, and the acoustic resonance phenomenon can be reliably avoided.
[0017]
In addition, since the power consumed by the lamp 10 is small and the output voltage of the DC power supply 1 becomes the maximum value from the start of lighting until the stable lighting state is reached, the output voltage control (steps S110 to S114). ) May be omitted. Furthermore, since this period is a transition period in which the luminous flux rises, the frequency control may be increased.
[0018]
Further, when the frequency shift is slow after reaching the stable lighting state, the frequency control for avoiding the acoustic resonance phenomenon may be performed at a long interval. In this case, frequency control repeated at the interval A may be thinned out as appropriate. That is, in the interval A where the frequency control is repeated, the presence or absence of instability at the time of discharge is detected, and the next frequency control may be omitted only when it is not detected.
[0019]
In this regard, the output voltage control is the same, and it is determined whether or not the output value from the lamp power detection circuit 14 falls within a predetermined range in the interval B where the output voltage control is repeated. The next output voltage control may be omitted.
[0020]
Further, the output adjustment of the DC power supply 1 in the output voltage control (step S111) is preferably controlled so that the output voltage changes gently. By gently changing the light output from the lamp, the feeling of flickering when the user is present and discomfort due to a sudden change in light intensity can be reduced.
[0021]
In addition, the times X and Y set in the timer tx and the timer ty may be any time that does not relate to the frequency control and the output voltage control (does not interfere with each other), and about several seconds to several minutes are appropriate.
[0022]
In this embodiment, the sequence in which the frequency control and the output voltage control are alternately repeated has been described, but it goes without saying that any sequence may be used as long as the two controls are not executed simultaneously.
For example, a sequence in which output voltage control is performed a plurality of times in an interval where frequency control is repeated may be a sequence in which frequency control is performed a plurality of times in an interval where output voltage control is repeated. Furthermore, a sequence in which a period in which output voltage control is performed a plurality of times and a period in which frequency control is performed a plurality of times may be alternately repeated, or a sequence in which these are combined may be used.
[0023]
Embodiment 2. FIG.
In the first embodiment, continuous instability such as acoustic resonance phenomenon is distinguished from transient instability such as sodium flash that occurs when encapsulated sodium element is instantly vaporized. I couldn't. As a result, transient instability that does not cause a problem in lighting is detected and the lamp is turned off. In the present embodiment, this point is improved, and the transient instability that does not cause a problem in lighting is ignored and connected to the next control.
[0024]
The circuit configuration and the timing of frequency control and output voltage control are the same as in FIGS.
FIG. 4 is an example of a flowchart showing the relationship between frequency control and output voltage control of the high-pressure discharge lamp lighting device according to the present embodiment. Compared with the flowchart shown in FIG. 3, steps S101, S105, and S106 are newly added. Hereinafter, the operation will be described focusing on the newly added steps.
[0025]
The lighting operation starts (step S100), and the counter C is reset (step S101).
Frequency control is performed (step S102), and at the end of the frequency control, a timer tx is set (Tx = X) and started (step S103). With the start of the timer tx, the lamp voltage detection circuit 11 samples the lamp voltage and detects the presence or absence of instability during discharge (step S104). When the instability is detected, the counter C is incremented by one (step S105), and it is determined whether or not the incremented counter C has exceeded the predetermined number N (step S106). If it has exceeded, the control circuit 5 immediately stops the inverter circuit 2 and turns off the lamp 10 (step S107). On the other hand, if not exceeded, the process returns to immediately before the frequency control (step S102), and the above series of operations is repeated. The operation for detecting the presence or absence of instability during discharge is continued until the timer tx ends (Tx = 0) (steps S108 and S109).
[0026]
The series of operations from the next step S110 to step S114 is to control the output voltage of the DC power source 1 based on the detected value of the lamp power, and is the same as that described in the first embodiment. Omitted.
[0027]
When a lamp that cannot avoid acoustic resonance phenomenon such as a different rated lamp is mounted by the above operation, frequency control is repeated, and when the number of repetitions (count C) exceeds a predetermined number N. The lamp 10 is turned off.
[0028]
In addition, when a regular lamp is mounted, even if transient instability such as sodium flash occurs, the instability is settled with the number of repetitions not exceeding the predetermined number N, and the process proceeds from step S104 to step S108. The lighting can be continued and lighting can be continued.
[0029]
As described above, when transient instability that does not cause lighting problems such as sodium flash occurs, it can be ignored and the process can be shifted to the next control. If a general instability occurs, the lamp can be reliably turned off.
Further, as described in the first embodiment, since the sequence in which the frequency control and the output voltage control are alternately repeated is executed, the acoustic resonance phenomenon can be reliably avoided.
[0030]
As shown in FIG. 5, in the operation period of the timer ty, step S115 having a function equivalent to step S104 is provided after step S112, and when instability at the time of discharge is detected in step S115, the process proceeds to step S105. You may do it.
[0031]
Embodiment 3 FIG.
In the second embodiment, the light is turned off when the number of occurrences of instability at the time of discharge exceeds a predetermined number. However, in this embodiment, the duration of instability at the time of discharge has exceeded a predetermined value. A configuration that turns off in this case will be described. The circuit configuration and the timing of frequency control and output voltage control are the same as in FIGS.
[0032]
FIG. 6 shows an example of a flowchart showing the flow of frequency control and output voltage control in the present embodiment.
Steps S101 to S104 and Steps S107 to S114 are the same as those shown in the second embodiment, and thus description thereof will be omitted, and different points will be described.
Before the frequency control in step S102 is performed, the timer tz is set (Tz = Z) and started (step S116). If instability during discharge is detected in step S104, the process proceeds to step S102, and step S102 → step S103 → step S104 → step S102 is repeated until the instability disappears. When the timer tz ends in the repeating process (step S117), the control circuit 5 stops the inverter circuit 2 and turns off the lamp 10 (step S107). If the instability is not detected and the timer Tx ends in step S108, the timer Tz is also reset (step S109).
[0033]
With the above operation, for example, when a lamp that cannot avoid an acoustic resonance phenomenon such as a different rated lamp is mounted, the frequency control is repeated, and the lamp 10 is turned off when the repetition time Tz exceeds the predetermined time Z. .
[0034]
When a regular lamp is mounted, even if transient instability such as sodium flash occurs, the instability is settled in a time not exceeding the predetermined time Z, and the process proceeds from step S104 to step S108. And can continue to light up. In other words, the continuous instability that should be avoided due to the acoustic resonance phenomenon is distinguished from the transient instability that does not cause a lighting problem such as sodium flash, and it is possible to process whether to continue lighting.
[0035]
As described above, when transient instability that does not cause a problem in lighting such as sodium flash occurs as in the second embodiment, it can be ignored and transferred to the next control. When continuous instability such as an acoustic resonance phenomenon occurs, the lamp can be reliably turned off.
Further, as described in the first embodiment, since the sequence in which the frequency control and the output voltage control are alternately repeated is executed, the acoustic resonance phenomenon can be reliably avoided.
[0036]
In the second and third embodiments, the frequency control algorithm may be any method as long as it is frequency control for avoiding the acoustic resonance phenomenon, but the time required for one frequency control is determined by the timer tx. , Ty is desirably sufficiently smaller than the times X and Y set.
[0037]
【The invention's effect】
According to the high pressure discharge lamp lighting device of the present invention, the high pressure discharge lamp, the tube voltage detecting means for detecting the tube voltage of the high pressure discharge lamp, the high frequency power supply circuit for supplying AC power of 1 kHz or more to the high pressure discharge lamp, A control circuit for controlling the output power and output frequency of the high-frequency power supply circuit and a power detection circuit for detecting the power applied to the high-pressure discharge lamp, the control circuit including an acoustic resonance frequency unique to the high-pressure discharge lamp In addition to controlling the output frequency in a non-frequency band, the output voltage of the DC power supply is controlled so that the value detected from the power detection circuit falls within a predetermined range. without running simultaneously, and frequency control, the output voltage control, since it is configured to repeat alternately, the control for avoiding the acoustic resonance phenomena, controlled reliably respectively to keep the lamp power constant Ukoto can.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram showing a circuit configuration of a high-pressure discharge lamp lighting device according to Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram for explaining the timing of frequency control and output voltage control of the high pressure discharge lamp lighting device according to Embodiment 1 of the present invention.
FIG. 3 is a flowchart showing the relationship between frequency control and output voltage control of the high pressure discharge lamp lighting device according to Embodiment 1 of the present invention.
FIG. 4 is an example of a flowchart showing a relationship between frequency control and output voltage control of the high pressure discharge lamp lighting device according to Embodiment 2 of the present invention.
FIG. 5 is another example of a flowchart showing the relationship between frequency control and output voltage control of the high pressure discharge lamp lighting device according to Embodiment 2 of the present invention.
FIG. 6 is a flowchart showing the relationship between frequency control and output voltage control of a high pressure discharge lamp lighting device according to Embodiment 3 of the present invention.
[Explanation of symbols]
1 DC power supply 2 Inverter circuit 3, 4 MOSFET
5 Control Circuit 6 Load Circuit 7 Choke Coil 8 DC Cut Capacitor 9 Start Circuit 10 High Pressure Discharge Lamp 11 Lamp Voltage Detection Circuit 12 Timer 13 Detection Resistance 14 Lamp Power Detection Circuit

Claims (10)

A high pressure discharge lamp,
Tube voltage detecting means for detecting the tube voltage of the high pressure discharge lamp;
A high frequency power supply circuit for supplying AC power of 1 kHz or more to the high pressure discharge lamp;
A control circuit for controlling the output power and output frequency of the high-frequency power supply circuit;
A power detection circuit for detecting power applied to the high pressure discharge lamp,
The control circuit includes:
While controlling the output frequency in a frequency band that does not include the acoustic resonance frequency unique to the high-pressure discharge lamp,
Controlling the output voltage of the DC power supply so that the value detected from the power detection circuit falls within a predetermined range;
In executing these two controls, do not execute the two controls at the same time .
The high pressure discharge lamp lighting device , wherein the frequency control and the output voltage control are alternately repeated . A high pressure discharge lamp,
Tube voltage detecting means for detecting the tube voltage of the high pressure discharge lamp;
A high frequency power supply circuit for supplying AC power of 1 kHz or more to the high pressure discharge lamp;
A control circuit for controlling the output power and output frequency of the high-frequency power supply circuit;
A power detection circuit for detecting power applied to the high pressure discharge lamp,
The control circuit includes:
While controlling the output frequency in a frequency band that does not include the acoustic resonance frequency unique to the high-pressure discharge lamp,
Controlling the output voltage of the DC power supply so that the value detected from the power detection circuit falls within a predetermined range;
In executing these two controls, do not execute the two controls at the same time.
In the interval where the frequency control is repeated,
High圧放lamp lighting apparatus you and performing a plurality of times the output voltage control. A high pressure discharge lamp,
Tube voltage detecting means for detecting the tube voltage of the high pressure discharge lamp;
A high frequency power supply circuit for supplying AC power of 1 kHz or more to the high pressure discharge lamp;
A control circuit for controlling the output power and output frequency of the high-frequency power supply circuit;
A power detection circuit for detecting power applied to the high pressure discharge lamp,
The control circuit includes:
While controlling the output frequency in a frequency band that does not include the acoustic resonance frequency unique to the high-pressure discharge lamp,
Controlling the output voltage of the DC power supply so that the value detected from the power detection circuit falls within a predetermined range;
In executing these two controls, do not execute the two controls at the same time.
In the interval where the output voltage control is repeated,
High圧放lamp lighting apparatus you and performing a plurality of times the frequency control. The control circuit includes:
In the interval where the output voltage control is repeated,
The output value from the power detection circuit determines whether within a predetermined range, only if fit, of any one of claims 1 to 3, characterized in that omitting the next output voltage control High pressure discharge lamp lighting device. The control circuit includes:
In the interval where the frequency control is repeated,
Detecting the presence or absence of instability during discharge based on the output value from the tube voltage detecting means, only when not detected, any of claims 1 to 4, characterized in that omitting the next frequency control The high pressure discharge lamp lighting device according to claim 1. The control circuit includes:
In the interval where the frequency control is repeated,
The presence or absence of instability at the time of discharge is detected based on the output value from the tube voltage detecting means, and only when it is detected, returns to the frequency control immediately before the operation for detecting this instability. Item 6. The high pressure discharge lamp lighting device according to any one of Items 1 to 5 . The control circuit includes:
The high pressure discharge lamp lighting device according to claim 6 , wherein the high pressure discharge lamp is turned off when the operation of returning to the immediately preceding frequency control is repeated more than a predetermined number of times. The control circuit includes:
7. The high pressure discharge lamp lighting device according to claim 6 , wherein the high pressure discharge lamp is turned off when the operation of returning to the immediately preceding frequency control is continued beyond a predetermined time. The control circuit includes:
In the output voltage control,
The high pressure discharge lamp lighting device according to any one of claims 1 to 8 , wherein control is performed to gently change the output voltage of the DC power supply. The high pressure discharge lamp lighting device according to any one of claims 1 to 9 , wherein the output voltage of the DC power supply is maintained at a constant value for a predetermined period after the lighting is started.

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