JP2011243393A - Device and method for lighting xenon lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a xenon lamp which prevents useless power loss before reaching a luminance to use, secures a long and stable lighting time and achieves life prolongation of the lamp.SOLUTION: A xenon lamp lighting device includes a charging circuit (200) and a current control circuit (300) which supplies a current to the xenon lamp in accordance with a lamp current setting value using a charge voltage of the charging circuit as a power supply. The current control circuit includes a control part (26) which controls the lamp current setting value. During the period from the lighting start time to the time of reaching the luminance to use, the control part is configured to increase the lamp current setting value from the lamp current setting value which is lower than the lamp current setting value (i1) in the luminance to use to the lamp current setting value in the luminance to use.

Description

  The present invention relates to a xenon lamp lighting device used for a simulated sunlight irradiation device that irradiates simulated sunlight.

  In order to measure the performance of various solar energy utilizing devices such as the photoelectric conversion characteristics of solar cells, a pseudo solar irradiation device that irradiates an object to be irradiated with pseudo sunlight that reproduces the spectral distribution of natural sunlight is known. In this type of simulated sunlight irradiating device, a light source composed of a xenon lamp is installed in a box, and simulated sunlight is emitted from the radiation surface by irradiating light from the light source through an optical filter.

  In this apparatus, for example, a xenon lamp having a light emission length of 1000 mm or more (hereinafter referred to as “lamp”) is used, a direct-current lamp current is applied, and the lamp current value is adjusted by the lighting device, whereby the illuminance on the irradiated surface Is controlled. Generally, the lamp current at the time of lighting is several tens of amperes (for example, 70 A), the lamp voltage is about several hundred volts (for example, 500 V), and this lamp current / voltage is several tens of mSec per lighting. Energized / applied over 100 mSec. This output state is controlled by constant current or constant power, and the performance of the irradiated object is measured during the lighting period.

  In the above case, the lamp power is 35 kW, and even if it is instantaneous (for example, 100 mSec), if this power is supplied directly from the commercial power supply, it will cause a failure in peripheral devices of the same commercial power system, A problem arises in that a large-capacity contact and wiring are required between them. Therefore, generally, a configuration is adopted in which a lighting device is provided in the irradiation device, electric power is accumulated in the lighting device, and the accumulated power is supplied to the lamp in response to a lighting command.

  FIG. 4 shows a conventional lighting device. The AC power supply 1 is converted into a DC voltage by the DC power supply circuit 100 including the rectifier 2 and the smoothing capacitor 3, and the DC voltage is supplied to the charging circuit 200. Charging circuit 200 includes an inverter composed of transistors 4, 5, 6 and 7. In accordance with a charging command to the charging circuit 200, the conduction time of the transistors 4, 7 and the transistors 5, 6 is controlled by the PWM control circuit 8 and is alternately conducted at a high frequency. As a result, an AC voltage is generated in the primary winding of the transformer 9 and a voltage corresponding to the boost ratio is generated in the secondary winding of the transformer 9. The voltage generated in the secondary winding of the transformer 9 is rectified by the rectifier 10, smoothed by the coil 11, and charged to a large capacity electrolytic capacitor (charging capacitor) 13. Here, the voltage proportional to the charging current detected by the current detection resistor 12 (that is, the voltage between B and G) and the reference voltage 15 are input to the error amplifier 14, and the PWM control circuit 8 so that they are equal. As a result, the conduction time of the transistors 4 to 7 is PWM-controlled. As a result, the large-capacity charging capacitor 13 is charged with a constant current at a predetermined current value. When the charging capacitor 13 is charged to a voltage sufficiently higher than the lamp voltage (for example, 1000 V), the PWM control circuit 8 temporarily stops the operation of the inverter (or holds the charging voltage) and enters a standby state.

  Next, the current control circuit 300 starts operating in response to the lamp lighting command. The current control circuit 300 includes a step-down chopper circuit, and the step-down chopper circuit is a PWM control circuit 21 that controls the conduction time of the semiconductor switch 16 such as an IGBT, the diode 17, the coil 18, the capacitor 19, the current detection resistor 20, and the semiconductor switch 16. , An error amplifier 22, a reference voltage 23, and a feedback element 27. At this time, a DC voltage (1000 V) almost equal to the voltage of the charging capacitor 13 is immediately applied across the lamp 25. Thereafter, a pulse voltage is superimposed on the DC voltage by a pulse transformer 24 of an igniter (not shown), and dielectric breakdown of the lamp 25 occurs.

  When the lamp 25 undergoes dielectric breakdown, a limited current from the current control circuit 300 is input to the lamp 25 using the charging voltage of the capacitor 13 as a power source. In the current control circuit 300, a voltage signal (detection voltage) proportional to the lamp current and a voltage signal (reference voltage) from the reference voltage 23 proportional to the lamp current set value are input to the error amplifier 22 so that they are equal. Further, the conduction time of the semiconductor switch 16 is PWM controlled by the PWM control circuit 21. As a result, the DC lighting of the lamp 25 using the capacitor 13 as a power source is controlled at a constant current according to the lamp current set value.

  By the way, the operation from the start of lighting of the lamp until reaching the working illuminance has not received much attention so far. FIG. 5 shows the lamp current set value (thick dotted line), the lamp current, and the illuminance in the conventional example. In addition, the vertical axis | shaft (SUN) of the right side of a figure represents ratio with respect to the value at the time of use illumination intensity about each value. As shown in the figure, the lamp current set value is constant at i1, but after several mSec from the start of lighting (at t1), the lamp current reaches the lamp current set value and becomes constant, and the lamp current becomes constant. Further, the illuminance increases by a few mSec (at t2) and reaches the used illuminance. That is, it can be seen that the illuminance does not follow quickly even when the lamp current becomes constant at the lamp current set value.

  However, there is a problem in that useless power loss occurs due to an excessive lamp current before reaching the use illuminance. Moreover, since the energy of the charging capacitor is discharged unnecessarily due to this excessive lamp current, the time during which stable lighting can be performed with subsequent illuminance is shortened, and the performance as a simulated sunlight irradiation device is impaired. It is. Further, excessive lamp current causes stress on the lamp, and there is a problem that the lamp has a short life. Experiments have shown that increasing the lamp current before reaching the operating illuminance does not significantly increase the rate of increase in illuminance.

  Therefore, an object of the present invention is to solve the above-described problem by suppressing an excessive lamp current before reaching the use illuminance.

  A first aspect of the present invention is a xenon lamp lighting device including a charging circuit (200) and a current control circuit (300) that supplies current to the xenon lamp according to a lamp current setting value using a charging voltage of the charging circuit as a power source. Then, the current control circuit has a control unit (26) for controlling the lamp current set value, and the control unit sets the lamp current set value between the start of lighting and the time when the use illuminance is reached. It is a xenon lamp lighting device configured to increase from a lamp current setting value lower than the value (i1) to a lamp current setting value at the operating illuminance.

  A second aspect of the present invention is a xenon lamp lighting method in which a charging voltage of a charging circuit is used as a power source, and a current control circuit supplies current to the xenon lamp according to a lamp current setting value. ) After starting the lighting of the xenon lamp, the step of setting the lamp current setting value to a lamp current setting value lower than the lamp current setting value (i1) in the operating illuminance; and (B) until the illuminance of the xenon lamp reaches the operating illuminance. And a step of increasing the lamp current set value to obtain the lamp current set value at the illuminance used.

  In the first and second aspects, the control unit preferably increases the lamp current set value in accordance with the follow-up speed of illuminance.

It is a figure which shows the xenon lamp lighting device by the Example of this invention. It is a figure explaining the Example of this invention. It is a figure which shows the modification of this invention. It is a figure which shows the modification of this invention. It is a figure which shows the conventional xenon lamp lighting device. It is a figure explaining a prior art example.

  FIG. 1 shows a xenon lamp lighting device according to an embodiment of the present invention. In the figure, the DC power supply circuit 100, the charging circuit 200, and the igniter circuit (not shown) are the same as those of the conventional example shown in FIG. The present invention is different from the conventional example in that the current control circuit 300 includes a CPU (control unit) 26. Note that the CPU may be inside or outside the current control circuit 300.

  More specifically, in the circuit of FIG. 1, not a fixed voltage power supply but a CPU capable of voltage control is connected to the reference voltage side of the error amplifier 22. That is, in the current control circuit 300, in response to the lighting command, a voltage signal proportional to the lamp current and a variable voltage signal from the CPU 26 proportional to the set value of the lamp current are input to the error amplifier 22, and both become equal. As described above, the PWM control circuit 21 performs PWM control of the conduction time of the semiconductor switch 16. Thus, the lamp current is controlled at a constant current according to the controllable lamp current setting value using the capacitor 13 as a power source. In the present embodiment, the CPU 26 increases the lamp current setting value in accordance with the follow-up speed of the lamp illuminance.

FIG. 2 shows the lamp current set value (thick dotted line), the lamp current, and the illuminance in this example.
At the start of lighting, the lamp current set value is set to a set value i0 (for example, i0 = 46.5A, SUN = 0.66) lower than the set value i1 (i1 = 70 A in the present embodiment) in the working illuminance. The lamp current becomes constant at a current value i0 about 1 mSec after the start of lighting. When the illuminance follows SUN 0.66 at about 5 mSec (t1 ') after the start of lighting, the lamp current set value is raised from i0 to i1. Then, at t2, the illuminance follows up to the illuminance used (SUN = 1.00). It is assumed that the follow-up speed of illuminance is known in advance by experiments or the like.

  In this way, when this embodiment of FIG. 2 is compared with the conventional example of FIG. 5, even if the time t2 from the start of lighting until reaching the use illuminance is the same, the lamp current value (integrated value) until then is the same. It can be seen that there is less in this embodiment, and the excessive lamp current before reaching the use illuminance is reduced.

  With the above configuration, it is possible to prevent useless power loss before reaching the use illuminance. In addition, since the energy of the charging capacitor is not discharged unnecessarily (after t2), it is possible to ensure a longer lighting time at the usage illuminance. Further, since the stress on the lamp is small, the life of the lamp can be extended. Thereby, a highly efficient, high-performance and highly reliable pseudo-sunlight irradiation device can be provided.

  In the above-described embodiment, the lamp current set value increases step by step. However, the lamp current set value may increase continuously as shown in FIG. 3A. In the embodiment, the increase in the lamp current set value is shown as being in two stages, but it may be three or more stages as shown in FIG. 3B. Furthermore, in the embodiment of FIG. 2, the lamp current set value is monotonically increased. However, as shown in FIG. 3A or 3B, the lamp current set value is increased or decreased from the start of lighting until the use illuminance is reached. May be.

  In the above embodiment, the current control circuit 300 is configured with a feedback circuit using an error amplifier. However, a feedforward configuration in which PWM control is forcibly performed may be employed. In this case, a signal relating to the lamp current setting value from the CPU 26 is directly input to the PWM control circuit 21.

16. Semiconductor switch 17. Diode 18. Coil 19. Capacitor 20. Detection resistor 21. PWM control circuit 22. Error amplifier 26. CPU (control unit)
100. DC power supply circuit 200. Charging circuit 300. Current control circuit

Claims (4)

A xenon lamp lighting device comprising a charging circuit (200) and a current control circuit (300) for supplying current to a xenon lamp according to a lamp current setting value using a charging voltage of the charging circuit as a power source,
The current control circuit has a control unit (26) for controlling the lamp current setting value, and the control unit converts the lamp current setting value from the start of lighting until the use illuminance is reached. A xenon lamp lighting device configured to increase from a lamp current set value lower than the current set value (i1) to a lamp current set value at the use illuminance.   2. The xenon lamp lighting device according to claim 1, wherein the control unit increases the lamp current set value in accordance with a follow-up speed of the illuminance. A method of lighting a xenon lamp using a charging voltage of a charging circuit as a power source and supplying a current to the xenon lamp according to a lamp current setting value by a current control circuit,
In the current control circuit,
(A) after starting the lighting of the xenon lamp, the step of setting the lamp current setting value to a lamp current setting value lower than the lamp current setting value (i1) in the operating illuminance; and (B) the illuminance of the xenon lamp is the operating illuminance A lighting method comprising a step of increasing the lamp current set value to reach the lamp current set value at the operating illuminance before reaching the value.   4. The lighting method according to claim 3, wherein in the step (B), the lamp current set value is increased in accordance with the follow-up speed of the illuminance.

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