JP2005158366A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of preventing abnormal heat generation of a stabilizer and a lamp socket even if the lamp in discharge condition in an outer tube is a load. <P>SOLUTION: In this discharge lamp lighting device for lighting a high voltage discharge lamp by applying almost rectangular wave electric power of low frequency from a lighting circuit including at least switching elements, the device includes detection means for detecting an instantaneous value of a voltage or a current of the discharge lamp, wherein the detection means detects an instantaneous level of voltage or current immediately after polarity reversal of the almost rectangular wave or during a certain period from the polarity reversal, determines an abnormal condition when exceeding a predetermined threshold value and stops or reduces an output of the lighting circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a discharge lamp lighting device for lighting a HID lamp.

  HID lamps are used in a wide range of fields because of their high brightness and high efficiency depending on the type. In particular, high-color-rendering metal halide lamps have recently been used for spotlights and downlights in indoor stores, taking advantage of their characteristics. Therefore, the design of the lamp is also important, and smaller lamps are preferred. Therefore, in recent years, electronic ballasts using many electronic components for the purpose of reducing the weight, size and function of ballasts are becoming mainstream. This electronic ballast will be briefly described below.

  In general, the electronic ballast of an HID lamp often employs a rectangular wave lighting system in order to avoid an acoustic resonance phenomenon. The basic idea of the rectangular wave lighting method is to reduce the current limiting element by limiting the current limiting of the lamp current in the high frequency range, while reducing the high frequency current to a low frequency that does not cause an acoustic resonance phenomenon. Inverting the polarity and supplying the lamp with a low-frequency current consisting only of the low-frequency component, with the high-frequency component removed by the filter circuit, enables stable lighting of the discharge lamp while avoiding acoustic resonance. ing.

  FIG. 8 shows a block diagram of the electronic ballast. A DC power supply circuit section A including a rectifier circuit is connected to the AC power supply Vs, and an inverter circuit section B that generates low-frequency rectangular wave power is connected to an output terminal of the DC power supply circuit section A. This inverter circuit The lamp La is connected to the output end of the part B. The inverter circuit unit B includes an igniter circuit (not shown), and generates a high voltage pulse voltage at the time of starting.

  A more specific circuit diagram of the block diagram of FIG. 8 is shown in FIG. The DC power supply circuit section A includes a rectifier circuit DB, a switching element Q0, a diode D0, an inductance L0, a capacitor C0, and a control circuit S0. The switching element Q0, the diode D0, and the inductance L0 constitute a boost chopper circuit, and the AC power supply Vs It has the function of rectifying and smoothing AC voltage into DC voltage. Since the operation of the step-up chopper circuit is general, it will be omitted.

  The inverter circuit section B includes switching elements Q1 to Q4, diodes D1 to D4, an inductance L1, a capacitor C1, a control circuit S1, and driver ICs (for example, IR2308 manufactured by IR) K1 and K2. The control circuit S1 detects the lamp voltage of the lamp La with resistors R1 to R4, performs ON / OFF control of the switching elements Q1 to Q4 according to the lamp voltage, and supplies appropriate power to the lamp La.

FIG. 10 shows a timing chart of the switching elements Q1 to Q4. At the time of lighting, the switching elements Q1 and Q2 operate at several tens to several hundreds Hz, and the switching elements Q3 and Q4 operate at several tens KHz, so that a current like I _L1 in FIG. 10 flows through the inductance L1. Further, a substantially rectangular wave current such as Ila from which the high frequency component of I _L1 has been removed by the capacitor C1 flows through the lamp La.

Here, the control circuit S1 may use a microcomputer. In that case, the lamp voltage recognizes the value obtained by A / D converting the voltage divided by the resistors R1 to R4 as a lamp voltage value. That is, in order to detect the lamp voltage, the absolute value of the difference between the both-ends voltage V _R2 of the resistor _R2 and the both-ends voltage V _R4 of the resistor R4 can be obtained and recognized as the lamp voltage value.

  FIG. 11 shows a flowchart of the main program of the microcomputer. The operation of the program will be briefly described below. First, the low frequency of a rectangular wave is set. Here, it was set to 170 Hz. Thereafter, the switching elements Q2 and Q3 operate as shown in FIG. Then, the lamp voltage during a half cycle of the rectangular wave frequency is read, A / D converted, and a value is written as Vla2. From the value, a suitable power is read from the lamp voltage-lamp power data table stored in the microcomputer in advance. Thereafter, the switching elements Q2 and Q3 stop operating, and all the switching elements are turned off so that the switching elements Q1 to Q4 are not turned on simultaneously (steps 1 to 7).

  Next, the switching elements Q1 and Q4 perform an ON / OFF operation so that power can be supplied to the lamp in accordance with the power table corresponding to the lamp voltage one time before. Then, the A / D conversion value of the lamp voltage during the low frequency half cycle is written as Vla1, and the power table is read. Thereafter, after the switching elements Q1 and Q4 stop operating, all the switching elements are turned off as before, and then the operation returns to the operation of the switching elements Q2 and Q3 again. Can be performed (steps 8-13).

  In general, a high-pressure discharge lamp tends to increase the lamp voltage as the lighting time elapses from the beginning of lighting. Normally, in the case of a copper-iron type ballast, when the lamp voltage increases in this way, the re-ignition voltage of the lamp increases, so that the lighting cannot be maintained and the lamp is extinguished.

  On the other hand, in the electronic ballast, the re-ignition voltage is less likely to occur at the end of the life than the copper iron ballast, so it does not disappear easily. In this respect, the lamp life was also extended. However, since the lamp does not go out, the lamp is further loaded as compared with the copper-iron ballast, so that the arc tube inside the lamp may be deteriorated and cracks may occur. At that time, in a high-pressure discharge lamp in which the inside of the lamp outer tube is evacuated in order to improve the luminous efficiency of the lamp, a luminescent substance or the like may be emitted from the arc tube into the outer tube. In this case, the inside of the outer tube that has been evacuated is no longer vacuum, and the gas pressure rises, so that discharge may occur between conductors having a potential difference in the outer tube. In the present specification, the discharge generated in the outer tube due to the abnormality of the arc tube is referred to as “outer tube discharge”. If this discharge occurs in the outer tube, the overcurrent exceeding the rated current value is supplied from the ballast, which increases the temperature of the ballast, and heat is generated more than usual in the lamp cap, lamp socket, and lead wire. This will lead to life deterioration. This outer tube discharge may occur in a copper-iron ballast as well.

  As a means for preventing the discharge in the outer tube, a method of sealing an inert gas such as nitrogen in the outer tube is known. In this case, the heat in the arc tube is easily transmitted to the outside by the gas in the outer tube. As a result, the arc tube temperature is lowered, and the efficiency is lowered.

In addition, as a means for interrupting an overcurrent when an outer tube discharge occurs, a method is also known in which a current fuse is disposed in the base, the current fuse is blown by the overcurrent, and the supplied power is cut off. (Patent No. 3126300). In this case, since a larger current flows at the time of starting the lamp than when it is stable, it is necessary to use a current fuse that does not blow at that current value. For this reason, even if an overcurrent flows due to the discharge in the outer tube, depending on the current value, it may take a long time until the current fuse is blown or may not blow. Therefore, the current fuse cannot reliably prevent damage to the ballast or the socket. In addition, since the base portion becomes high temperature, the current fuse is oxidized and becomes non-conductive, and the lamp may be turned off.
Japanese Patent No. 3126300

  The present invention has been devised to solve the above-mentioned points, and the object of the present invention is to prevent abnormal heat generation of the ballast and the lamp socket even when the lamp in the discharge state in the outer tube becomes a load. The object is to provide a discharge lamp lighting device.

  In the present invention, in order to solve the above-described problems, in a discharge lamp lighting device for lighting a high-pressure discharge lamp by applying a low-frequency substantially rectangular wave power by a lighting circuit including at least a switching element, the voltage of the discharge lamp Or a detecting means for detecting an instantaneous value of the current, and the detecting means detects an instantaneous value level of the voltage or current for a certain period immediately after the polarity inversion of the substantially rectangular wave or from the polarity inversion, and exceeds a predetermined threshold value. In this case, it is determined that the output is abnormal, and the output of the lighting circuit is stopped or reduced. In other words, the instantaneous voltage (re-ignition voltage) or instantaneous current (overshoot current) immediately after the reversal of the rectangular wave is read and compared with a predetermined threshold value, so that the lamp in the outer tube discharge state is distinguished from the normal lamp.

  According to the present invention, the lamp voltage or lamp current immediately after polarity inversion is compared with a predetermined threshold value to determine a lamp in a state of discharge in the outer tube, and the output of the lighting device is stopped or reduced. Thus, there is an effect that it is possible to suppress abnormal heat generation in the lamp that is in the state of discharge in the outer tube.

  In a preferred embodiment of the present invention, the discharge state in the outer bulb of the lamp is detected by paying attention to the instantaneous voltage after the polarity inversion described above. The circuit diagram of this embodiment is shown in FIG. 9, and the flow of the main operation of the control circuit S1 is shown in FIG.

  When the arc tube breaks for some reason and the discharge state is in the outer tube, the lamp voltage and the lamp voltage waveform as shown in FIG. 12 are observed. The waveforms in FIG. 12 are the waveforms of the lamp voltage Vla and the lamp current Ila when the Philips CDM-T150W lamp is in the discharge state in the outer tube. As can be seen from FIG. 12, when the lamp is in the discharge state in the outer tube, it is observed as a steep voltage waveform (instantaneous voltage) immediately after the polarity inversion of the lamp voltage waveform. The lamp current is observed as a steep current waveform (overshoot current) at the moment when the instantaneous voltage of the lamp voltage disappears immediately after polarity reversal.

  FIG. 13 is an enlarged view of the waveform immediately after polarity inversion in FIG. As can be seen from this waveform, the instantaneous voltage of the lamp voltage Vla appears for about 200 μsec immediately after the polarity inversion, and then the overshoot current of the lamp current Ila flows for a short period.

  Therefore, the discharge state in the outer bulb of the lamp is detected by paying attention to the instantaneous voltage after the polarity inversion described above. The operation will be described with reference to the flowchart of FIG. 2 and FIG. The flowchart of FIG. 2 may be inserted between Step 2 and Step 3 and between Step 8 and Step 9 of the flowchart of FIG. First, the lamp voltage is read for a period t1 that is sufficiently shorter than the half-cycle period of the rectangular wave immediately after the polarity reversal and includes the instantaneous voltage (for example, when the frequency of the rectangular wave is 170 Hz, it may be about 500 μsec). To perform A / D conversion (reading of instantaneous lamp voltage). The value is Vt1. Next, the preset threshold value Vp and Vt1 are compared, and if Vt1 is larger than the threshold value Vp, 1 is added to the counter M as shown in FIG. Further, as shown in FIG. 1b, if Vt1 is smaller than the threshold value Vp, the process proceeds to step 3 (or step 9) in the flowchart of FIG. This operation is repeated, and when the counter M reaches a predetermined number X (for example, 10 times), the operation of the switching elements Q1 to Q4 is stopped to stop the power supply to the lamp.

  That is, the number of times the instantaneous value of the lamp voltage after polarity inversion exceeds a threshold value (set to 1.5 to 2 times the rated lamp voltage) is counted, and if it reaches the predetermined number, it is recognized that the lamp is abnormal (discharge in the outer tube). Then, the operation of the lighting device is stopped.

  By detecting the lamp in the discharge state in the outer tube by the above operation and stopping the operation of the lighting device, it is possible to suppress abnormal heat generation of the lighting device, the lamp socket, and the wiring.

  In this embodiment, the flow of FIG. 3 is inserted between steps 2 and 3 and steps 8 and 9 of the main flowchart shown in FIG. 11, and between steps 4 and 5 and steps 10 and 11 of FIG. 4 to which the flow of FIG. 4 is added. Hereinafter, the operation of the added flowchart will be described.

  First, the lamp voltage is read for a period t1 that is sufficiently shorter than the half-cycle period of the rectangular wave immediately after the polarity reversal and includes the instantaneous voltage (for example, when the frequency of the rectangular wave is 170 Hz, it may be about 500 μsec). To perform A / D conversion (reading the instantaneous value of the lamp voltage). A value obtained by multiplying the value by K (about 1.5 to 2 times or more) is defined as Vt2 (flow chart in FIG. 3).

  Next, Vla1 or Vla2 (A / D conversion value of the ramp voltage of the rectangular wave half cycle) and Vt2 (K times the lamp voltage instantaneous value after polarity inversion) obtained in the main flowchart of FIG. 11 are compared, and Vt2 If is greater, the counter M is incremented once. If Vt2 is smaller, the flow proceeds to step 5 (or step 11) in the flowchart of FIG. Thereafter, the operation is repeated according to the flowchart. When the counter M reaches a predetermined number of times X (for example, 10 times), the operation of the switching elements Q1 to Q4 is stopped to stop the power supply to the lamp (flowchart in FIG. 4).

  That is, as shown in FIG. 5, the average value (or effective value) of the lamp voltage for t1 hours after polarity reversal is P, and a value obtained by multiplying this by a predetermined value (Vt2 = P × K) and the lamp voltage over a half cycle. The average value (or effective value) of Vla2 is compared, and when the former is larger, it is determined as abnormal, and the number of times is counted. When the number of times reaches X, the output of the lighting device is stopped.

  In the present embodiment, a flow of “mask counter elapsed?” Is added to each of the flowchart of FIG. 2 or the flowchart of FIG. 4 and will be described with reference to FIGS. 6 and 7 respectively. The comparison command “mask counter elapsed?” In the figure determines whether a predetermined time has elapsed since the lamp was started. That is, if the predetermined time has not elapsed, the counter M is not added. In the HID lamp, a steep lamp current waveform (or voltage waveform) may be observed immediately after polarity inversion even immediately after starting a normal lamp. In order to prevent the mode from being erroneously detected as a discharge lamp in the outer tube, the time from the start of the lamp to the stabilization of the lamp (about 5 minutes) is effective in preventing erroneous detection of a normal lamp by not increasing the counter M.

  In any of the above configurations, the steep voltage waveform (instantaneous voltage) observed immediately after polarity reversal of the lamp voltage waveform during the discharge in the lamp outer tube was captured and determined as the discharge in the outer tube, but attention was paid to the lamp current waveform. The same effect can be obtained as a program that captures the overshoot current waveform, determines that the discharge is in the outer tube, and stops the output of the lighting device. Moreover, you may control so that the output of a lighting device may be reduced.

  As the lighting circuit, the full bridge type inverter circuit of FIG. 9 is illustrated, but if the circuit system supplies a low-frequency rectangular wave current to the lamp, for example, the step-down chopper circuit of FIG. A so-called five-stone type in which an inverting circuit is combined may be used, or the half-bridge type in FIG. In the figure, S0 and S2 are chopper circuit control circuits, and IG is an igniter.

  The present invention can be used in lighting equipment for offices, stores, and general homes.

It is a waveform diagram for explaining the principle of the present invention. It is a flowchart for demonstrating the basic operation | movement by the principle of FIG. 1 of this invention. It is a flowchart for operation | movement description of Example 1 of this invention. It is a flowchart for operation | movement description of Example 1 of this invention. It is a wave form diagram for operation | movement description of Example 1 of this invention. It is a flowchart for operation | movement description of Example 2 of this invention. It is a flowchart for operation | movement description of Example 2 of this invention. It is a block diagram which shows schematic structure of the conventional electronic lighting apparatus. It is a circuit diagram which shows the specific structure of the conventional electronic lighting device. It is a wave form diagram which shows the basic operation | movement of the conventional electronic lighting device. It is a flowchart which shows the basic operation | movement of the conventional electronic lighting device. It is a wave form diagram of a lamp voltage and a lamp current of a discharge lamp in an outer tube discharge state. FIG. 13 is an enlarged view of a waveform immediately after polarity inversion in FIG. 12. It is a circuit diagram which shows the other structural example of the electronic lighting apparatus used for this invention. It is a circuit diagram which shows the further another structural example of the electronic lighting apparatus used for this invention.

Explanation of symbols

Vp Threshold for determining discharge in the outer tube Vt1 Lamp voltage immediately after polarity inversion

Claims (6)

A discharge lamp lighting device for lighting a high-pressure discharge lamp by applying a low-frequency substantially rectangular wave power to a high-pressure discharge lamp by a lighting circuit including at least a switching element, the detection means including a detection means for detecting an instantaneous value of the voltage or current of the discharge lamp, By detecting the instantaneous value level of the voltage or current for a certain period immediately after the polarity inversion of the substantially rectangular wave, or when exceeding a predetermined threshold, it is determined as abnormal and the output of the lighting circuit is stopped or A discharge lamp lighting device characterized by being reduced. In a discharge lamp lighting device for lighting a high-pressure discharge lamp by applying a low-frequency substantially rectangular wave power to a high-pressure discharge lamp by a lighting circuit including at least a switching element, a detection means for detecting the voltage or current of the discharge lamp, and the detection means The average value or effective value of the half cycle of voltage or current is detected as the first detection value, and is sufficiently shorter than the half cycle of the voltage or current of the discharge lamp and includes the instantaneous voltage or instantaneous current at the rise of the rectangular wave An average value or effective value of voltage or current for a predetermined time after polarity reversal is detected as the second detection value, and when the second detection value is equal to or greater than a predetermined multiple of the first detection value, it is determined as abnormal. A discharge lamp lighting device characterized in that the output of the lighting circuit is stopped or reduced. The discharge lamp lighting device according to claim 1 or 2, further comprising a timer for counting the number of times determined to be abnormal or integrating the time, and after the timer counts the predetermined number of times or the predetermined time, the output of the lighting circuit is stopped or A discharge lamp lighting device characterized by being reduced. The discharge lamp lighting device according to any one of claims 1 to 3, wherein an abnormality determination mask period is provided so that the predetermined time from the start of the discharge lamp is not determined to be abnormal. . The discharge lamp lighting device according to any one of claims 1 to 4, wherein a load is a discharge lamp in a discharge state that occurs in an outer tube of a high-pressure discharge lamp and other than in a sealed arc tube. Discharge lamp lighting device. A lighting fixture comprising the discharge lamp lighting device according to any one of claims 1 to 5.

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