JP2010073556A - Discharge lamp lighting device, and light source device for solar simulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of surely lighting both lamps even if required starting voltages of respective lamps vary, in a discharge lamp lighting device to impress a starting pulse on the connection point of the lamps connected in series. <P>SOLUTION: The discharge lamp lighting device (1) to light a lamp unit (4) composed of first and second discharge lamps connected in series is provided with a DC output circuit (10) to supply a DC to the lamp unit, an ignitor circuit (20) to impress a starting high voltage pulse on the connection point of the first and second discharge lamp, and inductors (31, 32) connected to the DC output circuit and both the ends of the lamp unit respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lighting device for a discharge lamp that requires application of a high-pressure pulse at the time of starting, and particularly relates to improvement of starting property of a xenon flash lamp used as a light source of a solar simulator.

  A xenon flash lamp is used as a light source for a solar simulator because its emission spectrum is relatively close to that of sunlight and the rise of a luminous flux from the start of discharge is fast. Further, xenon flash lamps are classified as discharge lamps, and it is necessary to apply a high-pressure pulse at the start (at the start of discharge).

  FIG. 3 shows a conventional discharge lamp lighting device (for example, Patent Document 1). The lighting device includes a DC output circuit 10 for supplying a rectangular wave current to the lamp 40 and an igniter circuit 20 for applying a starting voltage to the lamp 40. The DC output circuit 10 includes a capacitor 11, a switching element 12 such as an IGBT, and a control circuit 13 for the switching element 12. The voltage charged in the capacitor 11 from a power supply circuit (not shown) is controlled by the switching element 12 while the discharge current is controlled by the lamp 40. Apply to. The igniter circuit 20 includes a pulse source 21 and a pulse transformer 22. The primary side of the pulse transformer 22 is connected to the pulse source 21, and the secondary side is connected in series to the lamp 40.

  A lighting operation will be described. Before starting the discharge, the impedance of the lamp 40 is infinite. When a pulse is generated in the pulse source 21 with the switching element 12 turned on, a high-pressure start pulse corresponding to the turn ratio is generated on the secondary side of the pulse transformer 22, and at the same time, the pulse voltage is applied to both ends of the lamp 40. Applied. When the lamp 40 is a xenon flash lamp, a pulse voltage having a peak value of about 10 to 30 kV is required.

  When the lamp 40 breaks down due to the pulse voltage, constant current control is performed by the control circuit 13 over a predetermined period, and then the switching element 12 is turned off. In the solar simulator, the predetermined period is 10 m to 120 ms, the lamp current is several tens A, and the lamp voltage is about several hundred volts.

In the above circuit configuration, since the main current (lamp current) of the circuit after the lamp is lit flows to the secondary side of the pulse transformer, it is necessary to design the transformer so that the transformer does not saturate or generate heat with respect to the current. Was getting bigger.
When a plurality of (for example, two) lamps 40 are connected in parallel, it is difficult to flow a current evenly through the lamps when they are connected in parallel, and the total lamp current is double that of a series connection, resulting in a large circuit loss. Therefore, it is common to use a series connection instead of a parallel connection.
However, when two lamps are connected in series in the configuration of FIG. 3, the igniter circuit 20 must output two starting pulse voltages (double the pulse voltage in the case of one), which increases the size of the circuit. In some cases, a separate device for ensuring safety (for example, strengthening of the insulating structure) may be required.

  As a countermeasure, the circuit configuration shown in FIG. 4 is adopted. In the configuration shown in the figure, the igniter circuit 20 is connected in parallel to one of the lamps 41 and 42 (the lamp 42 in the figure) connected in series, and a starting pulse voltage is applied to a connection point M of the lamp. In the configuration shown in the figure, a DC cut capacitor 23 is connected in series to the secondary winding of the pulse transformer 22, but the basic operation is the same as that shown in FIG.

With the above configuration, the main current does not flow on the secondary side of the transformer, and the transformer can be downsized. Further, start pulses are applied between the connection point M and the anode point A and between the connection point M and the cathode point K, respectively. That is, even if the lamps are connected in series, the start pulse is applied in parallel to the lamps, and it is sufficient to output a start pulse of one voltage from the igniter circuit 20.
Since the DC voltage of the capacitor 11 (hereinafter referred to as “DC voltage”) is about 1/100 of the starting pulse voltage, the pulse voltage applied between the points M-K and the point MA side is (DC Even if there is a difference in voltage, it can be regarded as almost equal.
JP 2007-66738 A

  However, in the configuration of FIG. 4, a problem occurs when there are variations in the required starting voltages of the two lamps. In other words, there is usually a variation in the required voltage for starting the lamp, and this variation can cause problems with lamp starting. For example, it is assumed that the voltage required for starting the lamp 42 is higher than that of the lamp 41. In this case, the lamp 41 starts discharging first when the start pulse voltage reaches the start required voltage of the lamp 41 (at the time when the start required voltage of the lamp 42 has not been reached). When the lamp 41 starts to discharge, the impedance of the lamp 41 decreases, and based on the energy of the pulse accumulated in the pulse transformer 22, the connection point M → the lamp 41 → the regenerative diode (not shown) of the switching element 12 → the capacitor 11, Alternatively, a current flows through the connection point M → the lamp 41 → a current path (for example, the capacitor 33). As a result, the potential at the connection point M drops to near the DC voltage (several hundred volts), and no pulse voltage is applied to both ends of the lamp 42 that has not yet started discharging. For this reason, the lamp 42 becomes inconspicuous, and as a result, the lamp 41 cannot maintain the discharge and is turned off as a whole.

  As shown in Table 1 to be described later, for example, when the required starting voltage of the lamp 41 is 14 kV and the required starting voltage of the lamp 42 is 17 kV, the astigmatism rate of the lamp 42 (resulting in both lamps) is 100%. End up.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lighting device that can reliably start both lamps even when the required starting voltages of the lamps vary in a configuration in which a starting pulse is applied to a connection point of lamps connected in series. .

  A first aspect of the present invention is a discharge lamp lighting device (1) for lighting a lamp unit (4) comprising first and second discharge lamps connected in series, and a direct current is passed through the lamp unit. And an igniter circuit (20) for applying a starting high-pressure pulse to the connection point of the first discharge lamp and the second discharge lamp, and further, both ends of the DC output circuit and the lamp unit. Is a discharge lamp lighting device provided with inductors (31, 32) connected to each other.

  According to a second aspect of the present invention, a discharge lamp is lit for lighting a lamp unit (4) connected in series with a first discharge lamp and a second discharge lamp having a higher voltage required for starting than the first discharge lamp. A device (1), a DC output circuit (10) for supplying a direct current to the lamp unit, and an igniter for applying a starting high-pressure pulse to a connection point between the first discharge lamp and the second discharge lamp The discharge lamp lighting device includes a circuit (20) and further includes an inductor connected between the DC output circuit and the first lamp.

  In the first or second aspect, the inductance of each inductor may be 100 μH or more and 10 mH. Furthermore, it is desirable that the inductance of each inductor is 100 μH or more and 1 mH.

  A third aspect of the present invention is a solar simulator light source device (100) comprising any one of the above-described discharge lamp lighting device (1) and lamp unit (4), wherein each discharge lamp constituting the lamp unit is a xenon flash lamp. ).

  According to the present invention, in a discharge lamp lighting device that applies a starting pulse to a connecting point of lamps connected in series, it is possible to start both lamps reliably even when there is a difference in the starting voltage of each lamp.

  In general, the present invention pays attention to the fact that the rectangular wave current applied to the lamp after the start of discharge is substantially direct current (around several tens of Hz), whereas the starting pulse has a high frequency (around several hundred kHz). This solves the problem by using an inductor whose impedance changes greatly depending on the current. In the present specification, “substantially direct current” means “direct current or 1 kHz or less”, and “high frequency” means “100 kHz or more”.

  FIG. 1 shows a circuit configuration according to an embodiment of the present invention. The solar simulator light source device 100 includes a discharge lamp lighting device 1 and a lamp unit 4, and the lighting device 1 includes a DC output circuit 10 and an igniter circuit 20, and further, an output terminal of the DC output circuit 10 (that is, the lamp unit 4 and Inductors 31 and 32 connected between the DC output circuit 10). The DC output circuit 10 and the igniter circuit 20 are the same as those in FIG. The period of flash emission by the DC output circuit 10 is 10 m to 120 ms (100 to 8.3 Hz), and the start pulse width output from the igniter circuit 20 is 1 μ to 10 μs (1 M to 100 kHz). These specific values may be determined according to the simulation conditions and the characteristics of the lamp used.

Here, it is assumed that the required starting voltage of the lamp 42 is higher than that of the lamp 41. When the lamp 41 starts discharging, the connection point M → the lamp 41 → the inductor 31 → the regenerative diode (not shown) of the switching element 12 → the capacitor 11 or the connection point M based on the energy of the pulse accumulated in the pulse transformer 22. → Lamp 41 → Inductor 31 → A current flows through some current path (for example, capacitor 33). At this time, the inductor 31 has a high impedance with respect to the start pulse having a high frequency, and a voltage V ₃₁ determined by the inductance and the frequency of the pulse is generated in the inductor 31. Therefore, the potential of the amount corresponding connection point M of the voltage V ₃₁ also lamp 41 starts to discharge held, a pulse voltage is applied to both ends of the lamp 42 that has not started yet discharge. Thereby, the lamp 42 can start discharging after the lamp 41.
Although the igniter circuit 20 is connected in parallel to the lamp 42 side, it may be connected in parallel to the lamp 41 side.

  Then, after both lamps 41 and 42 start to discharge, a rectangular wave current from the DC output circuit 10 is supplied to both lamps. Here, the rectangular wave has a time width of 10 m to 120 ms (100 Hz to 8.3 Hz) and is almost a direct current, and the impedance of the inductors 31 and 32 with respect to this is almost zero, so that the inductors 31 and 32 affect the lighting state. Never give.

  Further, as shown in FIG. 1, the capacitor 33 may be connected in parallel to the output side of the DC output circuit 10. As a result, the inductors 31 and 32 and the capacitor 33 constitute a noise filter, and the starting noise generated by the lamp and the inductor can be prevented from affecting the DC output circuit 10.

The same applies to the case where the lamp 42 starts discharging first. When the lamp 42 starts discharging first, current flows from the connection point M → the lamp 42 → the inductor 32 → the ground based on the energy of the pulse accumulated in the pulse transformer 22. As a result, a voltage V ₃₂ determined by the inductance and the frequency of the pulse is generated in the inductor 32, and the pulse voltage is applied to the lamp 41 that has not yet started discharging by holding the potential at the connection point M by the amount of the voltage V _32. Then, the lamp 41 starts discharging after the lamp 42.

The experimental results of this example are shown in Table 1. In the experiment, as described above, the start-up required voltage is 14 kV (lamp 41) and 17 kV (lamp 42), and the startability is improved by the presence or absence of the inductor and the inductance when it is present. It was confirmed. The starting pulse to be applied has a pulse width of about 3.5 μs (290 kHz) and a peak voltage of 30 kV in the no-load state, and the inductance values in the table are the inductances of the inductors 31 and 32, respectively. In addition, a bias voltage of about 700 V exists at the connection point M before the pulse is applied, but the bias voltage is sufficiently small with respect to the pulse voltage, so there is no influence on the experimental result.

In the conventional circuit without an inductor, the lamp 41 starts discharging when the pulse voltage reaches about 15 kV, but the lamp 42 becomes inconsequential. As a result, the lighting success rate is 0% as shown in Table 1. there were. On the other hand, in the circuit in which the inductor is inserted, the potential at the connection point M is maintained for about several μs even after the lamp 41 starts discharging. For example, when a 400 μH inductor is inserted, the lighting success rate is up to 96%. Rose.
In addition, what is necessary is just to select a specific inductance value suitably according to the difference of the starting required voltage between a pulse width (frequency), anticipated lamps, etc. The larger the inductance, the more the above effect can be exhibited. However, in order to secure the rising speed of the lamp current, each inductance should be about 10 mH or less, and more preferably 1 mH or less (100 A, 1 kV). . In the above experiment, the difference between the required starting voltages of the two lamps is 3 kV. However, if the difference is smaller than that, the above effect can be expected even if each inductance is set to about 50 μH.

As described above, the inductors 31 and 32 are connected between both output ends of the DC output circuit 10 and both ends of the lamp unit 4, so that even when lamps having different start-up voltages are combined and connected in series, it is ensured. It became possible to start discharging.
In addition, it has become possible to provide a solar simulator light source device that can perform a reliable simulation in a solar simulator in which a plurality of lamps need to be turned on simultaneously.

<Modification 1>
In the above embodiment, the lamp 41 and the lamp 42 are shown to cope with the case where the level of the required starting voltage is unknown. However, if the level is known in advance, either the inductor 31 or 32 can be omitted.
For example, the lamps are preliminarily screened into a group having a low required starting voltage (easy to be lit) and a group having a high required voltage (not easily lit), and a lamp having a low required starting voltage is mounted on the lamp 41 side. The inductor 32 may be omitted. Naturally, only the inductor 32 may be connected as a lamp having a low required starting voltage is mounted on the lamp 42 side.
Thereby, cost reduction of a lighting device can be achieved.

<Modification 2>
In the above embodiment, two lamps are used. However, it is possible to deal with the case of a larger number of lamps. In the solar simulator, the length and number of lamps that irradiate the panel are determined by the size of the panel. Further, when the lamp length is limited in order to obtain the desired light emission characteristics of the lamp, it may be necessary to divide the lamp into a plurality of lamps.
Here, even when there are three or more lamps (for example, four lamps), as shown in FIG. 2, the lamp unit 4 is divided into a first group 4a and a second group 4b of lamps, and their connection points. A starting pulse from the igniter 20 may be applied to M.
The above configuration is particularly useful when it is difficult to manage the voltage required for starting a plurality of lamps.

  In the above embodiment, the description has been made assuming that the discharge lamp is a xenon flash lamp, but (1) it is necessary to apply a high-pressure start pulse (3 k-50 kV / 100 k-1 MHz) at the start of discharge, and (2 The present invention can be applied to any discharge lamp (for example, a high-pressure discharge lamp) in which a substantially direct current (direct current to 1 kHz or less) lamp current is passed after the start of discharge.

It is a figure which shows the circuit structure by the Example of this invention. It is a figure explaining the modification of this invention. It is a figure which shows the conventional circuit structure. It is a figure which shows the conventional circuit structure.

Explanation of symbols

1. 3. Discharge lamp lighting device Lamp unit 10. DC output circuit 11. Smoothing capacitor 12. Switching element 13. Control circuit 20. Igniter circuit 21. Pulse source 22. Pulse transformer 23. Capacitors 31, 32. Inductor 33. Capacitors 41, 42. Lamp 100. Light source device for solar simulator

Claims (5)

A discharge lamp lighting device (1) for lighting a lamp unit (4) comprising first and second discharge lamps connected in series,
A direct current output circuit (10) for supplying a direct current to the lamp unit, and an igniter circuit (20) for applying a starting high-pressure pulse to a connection point between the first discharge lamp and the second discharge lamp. Become
Furthermore, a discharge lamp lighting device comprising inductors (31, 32) respectively connected between the DC output circuit and both ends of the lamp unit. A discharge lamp lighting device (1) for lighting a lamp unit (4) connected in series with a first discharge lamp and a second discharge lamp whose voltage required for starting is higher than that of the first discharge lamp,
A direct current output circuit (10) for supplying a direct current to the lamp unit, and an igniter circuit (20) for applying a starting high-pressure pulse to a connection point between the first discharge lamp and the second discharge lamp. Become
Furthermore, a discharge lamp lighting device comprising an inductor connected between the DC output circuit and the first lamp.   The discharge lamp lighting device according to claim 1 or 2, wherein the inductance of each inductor is 100 µH or more and 10 mH.   3. The discharge lamp lighting device according to claim 1, wherein the inductance of each inductor is 100 μH or more and 1 mH. 4.   A light source device (100) for a solar simulator, comprising the discharge lamp lighting device (1) according to any one of claims 1 to 4 and the lamp unit (4), and each discharge lamp constituting the lamp unit. Is a solar simulator light source device consisting of a xenon flash lamp.

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