JP2005353357A - Electronic ballast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic ballast capable of initializing an integral time by automatically determining replacement of a lamp without needing an external device. <P>SOLUTION: This electronic ballast 10 is provided with an integral time storage means 52 for storing a lighting integral time of the lamp 14 and used for controlling the lighting of the lamp based on the integral time. The electronic ballast is equipped with: a lighting history storage means 54 for recording current values and voltage values of the lamp in stably lighting it for every lighting occasion; and a determination means 56 for determining whether the lamp is replaced or not by comparing the lamp current value or the lamp voltage value in previous lighting stored in the lighting history storage means 54 with the lamp current value or the lamp voltage value in the present lighting; and is characterized by that the lighting integral time stored in the integral time storage means 52 is initialized when it is determined that the lamp is replaced by the determination means 56. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic ballast for a discharge lamp, and more particularly to an improvement of its lighting control mechanism.

In general, as shown in FIG. 1, the HID lamp has a characteristic that its luminous flux maintenance factor decreases with the lifetime. For this reason, even if the lighting power of the lamp is kept constant, the luminous flux changes at the beginning and end of the lifetime. In order to solve this problem, there is a method of accumulating lamp lighting times, obtaining a correction value from a light flux maintenance table prepared in advance in the microcomputer based on the accumulated time, and changing the lighting power (for example, patents). Reference 1). If this method is used, it is possible to suppress the change in the luminous flux due to the passage of the lifetime, but when the lamp is replaced, it is necessary to return the integration time to the initial state (0 hours). In order to return the accumulated time to the initial state, for example, a method is considered in which a switch is provided in a fixture or an electronic ballast body and the switch is operated when the lamp is replaced.
JP 2001-326086 A

However, in general, the equipment of the HID lamp and the electronic ballast body are rarely installed in a place where direct operation is possible, and even if a switch is provided, it is difficult to actually operate. In addition, providing a switch in an instrument or the like indicates that the product cost is high, and it is not preferable from the viewpoint of reliability.
The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic stability that can automatically determine that a lamp has been replaced and initialize an integration time without requiring an external device. Is to provide a vessel.

In order to achieve the above object, an electronic ballast of the present invention includes an accumulated time storage means for storing an accumulated lighting time of a lamp, and is an electronic ballast that controls the lighting of a lamp based on the accumulated time. Lamp current value or voltage value for each lighting occasion, lighting history storage means for recording each lighting opportunity, lamp current value or lamp voltage value at the time of previous lighting stored in the lighting history storage means, and lamp at the time of lighting this time Determination means for determining whether or not the lamp has been replaced by comparing the current value or the lamp voltage value, and when the determination means determines that the lamp has been replaced, stored in the integrated time storage means The accumulated lighting time is initialized.
In the electronic ballast described above, it is preferable that the determination unit starts the determination from a point in time when the lamp lighting integrated time has passed a predetermined time or more.

In the above electronic ballast, the determination means is configured such that the absolute value of the difference between the lamp current value or lamp voltage value at the previous lighting and the lamp current value or lamp voltage value at the current lighting is equal to or greater than a predetermined threshold value. It is preferable to determine that the lamp has been replaced.
In the electronic ballast described above, the determination means has an absolute value of a difference between a previous lamp current or voltage and a lamp current value or lamp voltage value at the time of lighting this time being equal to or greater than a predetermined threshold, and a lamp to be used. It is preferable to determine that the lamp has been replaced when the change is in a direction opposite to the aging characteristic.
In the electronic ballast described above, it is preferable that the electronic ballast is provided with a time-dependent characteristic calculating unit that calculates a time-dependent characteristic of the lamp from a lamp current value or a lamp voltage value at each lighting stored in the lighting history storage unit.

  According to the electronic ballast of the present invention, the lamp current value or voltage value at the time of stable lighting is recorded for each lighting opportunity, and the lamp at the time of previous lighting stored in the lighting history storage means Since the current value or lamp voltage value is compared with the lamp current value or lamp voltage value when the lamp is lit this time, it has a judgment means that determines whether or not the lamp has been replaced. Thus, the lamp lighting integration time can be initialized.

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an electronic ballast according to an embodiment of the present invention.
The electronic ballast 10 of the present embodiment includes a power supply circuit system 16 that supplies power from the AC power supply 12 to the lamp 14 and a lighting control circuit system 18 that controls the power supply circuit system 16.
The power supply circuit system 16 includes a noise filter 20 that removes noise components from the AC power supply 12, a rectifier circuit 22 that rectifies and smoothes AC, a boost converter circuit 24, a step-down converter circuit 26, and a rectangular wave circuit 28. And an igniter circuit 30. These are sequentially connected in parallel to the AC power supply 12, and the lamp 14 is connected to the output side of the igniter circuit 30. In addition, a lamp current detection circuit 32 and a lamp voltage dividing circuit 34 are provided, and information on the lamp current and lamp voltage is sent to the lighting control circuit system 18. The power supply circuit system 16 may be configured as a general electronic ballast, and is not limited to the example of this embodiment.

The lighting control circuit system 18 includes two analog ICs, a boost converter control IC 38 and a step-down converter control IC 40 that respectively control the boost converter circuit 24 and the step-down converter circuit 26, and a one-chip microcomputer 42 that integrally controls them. . The control ICs 38 and 40 and the one-chip microcomputer 42 are supplied with drive power (DC power) from the control DC / DC converter circuit 36. As the one-chip microcomputer 42, for example, MC68HC908QY4 (flash memory version 8-bit CPU) manufactured by Motorola may be used.
A lamp voltage signal is sent from the lamp voltage dividing circuit 34 to the one-chip microcomputer 42, so that the one-chip microcomputer 42 can constantly monitor the voltage of the lamp 14. On the other hand, a connection for sending a control start / stop signal to the step-up converter control IC 38 and the step-down converter control IC 40 is prepared from the one-chip microcomputer 42. The lamp current command value is sent from the one-chip microcomputer 42 to the step-down converter control IC 40. This signal is analog (direct current), and the output method is via a digital / analog converter (D / A converter) or PWM. A smoothed signal may be used. The one-chip microcomputer 42 outputs a rectangular wave driving signal to the rectangular wave circuit 28.

  With the above configuration, the one-chip microcomputer 42 performs lamp lighting control processing based on information from the external device (such as the dimmer 50) connected to the power supply circuit system 16, the temperature sensor 46, and the interface 48. Is programmed to do. In this embodiment, the one-chip microcomputer 42 is programmed so as to integrate the lighting integrated time when the lamp is turned on (lighting time integrating means 58), and the built-in nonvolatile memory stores the lamp integrated time and lighting. The lamp current or lamp voltage value for each opportunity is stored (integrated time storage means 52, lighting history storage means 54). Then, it is programmed to determine whether or not the lamp has been replaced based on the stored accumulated time and the value of the lamp voltage or current for each lighting opportunity (determination means 56). That is, the determination unit 56 compares the lamp current value or lamp voltage value at the time of previous lighting stored in the lighting history storage unit 54 with the lamp current value or lamp voltage value at the time of lighting this time. It is determined whether or not. This determination is performed from the time when the integration time is equal to or longer than a predetermined determination start time. This determination start time is appropriately set based on the type of lamp used, the service life, and the like.

Further, the one-chip microcomputer 42 has a function that a general electronic ballast has, for example, a function that monitors the lamp voltage and outputs a lamp current command corresponding to the lamp voltage to the step-down converter control IC 40 so that the output power is optimized. The constant light beam function for adjusting the output power by reading the luminous flux correction factor table (see FIG. 10) prepared in advance in the microcomputer 42 from the lamp lighting integration time. A protective function for stopping the output, a temperature sensor 46 for monitoring the temperature of the electronic ballast 10 main body, and an abnormal temperature is recognized. Function to start / stop according to the state, cancel the dimming signal input from the external dimmer 50 for a certain time after the lamp lights Stable start function that, it is preferable that has a like.
The one-chip microcomputer 42 is connected to an interface 48 that insulates the electronic ballast from the outside. The interface 48 receives a continuous dimming signal (Duty signal: Duty ratio 0% to 100%) from an external device (the dimmer 50), and is capable of dimming the lamp by the external device. Yes.

The above is the schematic configuration of the electronic ballast of the present embodiment, and its operation will be described below.
Generally, the discharge lamp has different characteristics over time depending on the type, but as shown in FIG. 3, the load voltage gradually rises (FIG. 3 (a)) or falls (FIG. 3 (b)) according to the lifetime. Have FIG. 4 shows an example of the relationship between the accumulated lighting time and the transition of the lamp voltage. In this example, it is assumed that a lamp having a nominal life of 10,000 hours, a lighting voltage at the beginning of the life of 120 V, and a lamp that rises to 145 V at the end of the life is used. Further, the determination start time for starting the determination of whether or not the lamp has been replaced was set to 8000 hours. FIG. 4 shows an example in which the lamp is turned on continuously for a predetermined time and then turned off n times, and then the lamp is replaced with a new one.

First, the lamp that has just been replaced and has an early life is turned on (state 1). The lamp voltage (120.0 V) after a certain time has elapsed after lighting (during stable lighting) is recorded in the one-chip microcomputer. The lamp voltage is recorded only once for the first time of lighting. The recording of the lamp voltage is performed when the lamp is stably lit, for example, 5 minutes after the lamp is lit. Further, the integration and recording of the lighting time is updated every minimum unit time during the lighting.
After being turned on for 12 hours, it is turned off and then turned on again (state 2). Similarly, the value of the lamp voltage after a certain time has elapsed after lighting is recorded in the lighting history means. And the difference (DELTA) V of the lighting voltage in the last (state 1) and the lighting voltage in this time (state 2) is calculated | required. In the case of the example in FIG. 3, the voltage difference is 0.1 V, and since the integration time is less than the determination start time, it is assumed that the same lamp is lit (the lamp is not replaced). .

Similarly, the cycle of turning on / off is repeated until the end of the life (state n). After state n, the one that has been replaced with a new lamp and turned on is state n + 1. At this time, the difference ΔV between the lighting voltage in the previous time (state n) and the lighting voltage in the current time (state n + 1) is as large as 25 V, and the stored lighting integrated time exceeds the judgment start time (8000 hours). From this, it can be inferred that in the state n + 1, a lamp different from that in the state n is turned on. As a result, the integration time is returned to the initial state, and various functions using the integration time can be operated normally.
Summarizing the above operations, (1) the integration time is not initialized when the integration time is equal to or less than the determination start time or ΔV is equal to or less than the threshold, (2) the integration time is equal to or greater than the determination start time and ΔV is equal to or greater than the threshold. In this case, the integration time is initialized to 0 hour.

  The judgment start time and the threshold value of ΔV are changed according to the type of lamp and are recorded in advance in the one-chip microcomputer. In the above example, the replacement of the lamp is determined from the absolute value of the difference between the previous lamp voltage value and the current lamp voltage value, but may be determined in consideration of the temporal characteristics of the lamp to be used. . That is, when the aging characteristics of the lamp to be used are known in advance, the determination may be made by including the sign of ΔV in accordance with the aging characteristics of the lamp. For example, when the lamp voltage value increases according to the lighting integrated time (see FIG. 5A), the lamp voltage at the time of current lighting is smaller than the lamp voltage at the time of previous lighting, and the absolute value of the difference is predetermined. When the value is equal to or greater than the threshold value, it can be assumed that the lamp has been replaced. On the contrary, when the lamp voltage value decreases according to the lighting integrated time (see FIG. 5B), the lamp voltage at the current lighting is larger than the lamp voltage at the previous lighting and the difference between When the absolute value is equal to or greater than a predetermined threshold, it can be estimated that the lamp has been replaced.

It is also possible to program the one-chip microcomputer so that the lamp characteristics themselves are calculated from the storage of past lighting history. The electronic ballast 110 of the embodiment shown in FIG. 6 is obtained by adding a time characteristic calculation means 60 to the embodiment of FIG. Note that the same members as those in FIG.
As shown in FIG. 7, it can be estimated from the value of the lamp voltage at the past lighting opportunity whether the lamp voltage increases or decreases according to the integration time. Therefore, a rough temporal characteristic of the lamp used (whether the change in the lamp voltage with respect to the total lighting time is positive or negative) is estimated from the past lighting history by the temporal characteristic calculating means 60. Based on the time-dependent characteristics of the lamp thus obtained, the above lamp replacement may be determined. In other words, the absolute value of the difference between the lamp current value or lamp voltage value at the previous lighting time and the lamp voltage value at the current lighting time is larger than a predetermined threshold value, and the change in the direction opposite to the temporal characteristics of the lamp to be used. If there is, it may be determined that the lamp has been determined.

The time-dependent characteristics are calculated using the lamp voltage data for each lighting opportunity when the accumulated time is equal to or less than the determination start time. Since a sufficient amount of lighting history data is stored before the lamp integration time exceeds the determination start time, it is possible to estimate the lamp characteristics over time sufficiently accurately.
In the above example, whether or not the lamp has been replaced has been determined using the lamp voltage change ΔV, but of course the lamp current change ΔI may be used. Also, by connecting an illuminance detector that detects the illuminance of the lamp to a one-chip microcomputer, measuring and recording the illuminance of the lamp before correction by the accumulated time at each lighting, and watching the change in the illuminance of the lamp at each lighting A determination to replace the lamp may be made.

In addition, the above-described determination method may be properly used according to the lamp usage conditions. For example, when the lighting time is relatively short and lighting and extinguishing are repeated, the difference in lamp voltage at each lighting is small, and therefore it can be determined by the absolute value of the change ΔV. However, in the case of continuous lighting for a long time, the difference in lamp voltage at each lighting becomes large, so it is desirable to make a determination in consideration of the temporal characteristics of the lamp.
As described above, according to the electronic ballast of this embodiment, it is possible to automatically determine that the lamp has been replaced and to initialize the accumulated lamp lighting time. For this reason, it is not necessary to provide an external device such as a switch in the instrument or the electronic ballast body in order to initialize the accumulated time. In addition, since the user only needs to replace the lamp and does not need any other operation, labor can be saved and it is possible to prevent forgetting to initialize the accumulated time. Therefore, it is possible to perform illuminance correction according to the correct integration time.

Next, returning to FIG. 2 again, an example of the control program of the one-chip microcomputer of the electronic ballast of the embodiment of FIG. 2 will be described. FIG. 8 is a flowchart thereof.
The one-chip microcomputer 42 is set with a current command value table T1 and a luminous flux correction factor table T2, as shown in FIGS. Each of these table information is obtained in advance by experiment or calculation, and the value is recorded. The current command value table T1 in FIG. 9 is used to obtain a lamp current command value according to the lamp voltage detected by the lamp voltage dividing circuit 34, and the horizontal axis indicates the memory address corresponding to the lamp voltage. The vertical axis represents the current command value. Further, the luminous flux correction rate table T2 in FIG. 10 is for obtaining a correction rate according to the lighting integrated time in consideration of the lamp aging characteristics, and the horizontal axis corresponds to the elapsed time (lighting integrated time). The memory address and the vertical axis indicate the correction rate. By multiplying the current command value obtained from these two tables and the correction factor, a corrected current command value corresponding to the integration time is obtained.

The information amount of the tables T1 and T2 may be changed as appropriate according to the storage capacity of the one-chip microcomputer or other means.
The control program will be described below along the flow of FIG.
Step S1: The power is supplied to the one-chip microcomputer 42 from the DC / DC converter 36, and the program starts. This step includes an initialization process of the one-chip microcomputer 42 itself.
Step S2: The lamp lighting operation is started. Initialization processing of each variable is performed.
Step S3: The lamp voltage dividing circuit 34 detects the lamp voltage (Vl).
Step S4: the detection and lamp voltage, with reference to the pre-recorded table T1 (FIG. 9) in the one-chip microcomputer 42, selects the lamp current command value i _1.

Step S5: It is determined whether it is within 5 minutes from the start of lamp lighting. If it is within 5 minutes from lighting, it will move to step S22, and if it is 5 minutes or more, it will move to step S6. The time of 5 minutes here is an approximate time until the lamp operates stably.
Step S6: It is determined whether the lamp voltage (Vl) has been recorded in the nonvolatile memory (lighting history storage means 54) at the time of lighting this time. If stored, the process proceeds to step S14, and if not stored, the process proceeds to step S7.
Step S7: Refer to the accumulated time at the time of previous lighting already recorded in the nonvolatile memory (integrated time storage means 52).

Step S8: It is determined whether the integrated time taken out from the nonvolatile memory (integrated time storage means 52) in step S7 exceeds the determination start time. If the accumulated time exceeds the determination start time, the process proceeds to step S9, and if not, the process proceeds to step S13. Here, the determination start time is appropriately set in consideration of the nominal life of the lamp to be used. For example, if the nominal life is 10,000 hours, the determination start time for starting the determination is set to 8000 hours or the like.
Step S9: Refer to the lamp voltage at the time of previous lighting already recorded in the non-volatile memory (lighting history storage means 54).
Step S10: The difference ΔV is obtained from the lamp voltage at the previous lighting time taken out from the nonvolatile memory (lighting history storage means 54) at step S9 and the lamp voltage at the current lighting time.
Step S11: It is determined whether or not ΔV obtained in step S10 is equal to or greater than a threshold value. If it is equal to or greater than the threshold value, it is determined that the lamp has been replaced, and the process proceeds to step S12. If it is equal to or less than the threshold value, it is determined that the lamp has not been replaced, and the process proceeds to S13.

Step S12: Since it is determined that the lamp has been replaced in step S11, the accumulated time is set to 0 hour and recorded in the nonvolatile memory.
Step S13: The lamp voltage at the time of lighting this time is recorded in the nonvolatile memory (lighting history storage means 54). The lamp voltage is recorded only once per lamp operation.
Step S14: The current accumulated time is referred to from the nonvolatile memory (integrated time storage means 52).
Step S15: Refer to the luminous flux correction factor table T2 (FIG. 10) stored in advance in the non-volatile memory based on the integration time read in step S14.
Step S16: the light flux correction value obtained in step S15, from the current command value i ₁ obtained in step S4, and calculates a new current command value i _2.

Step S17: It is determined whether a continuous light control signal is input from the external device through the interface 48. If a signal is input, the process proceeds to step S18. If not input, the process proceeds to step S21.
Step S18: The dimming signal is taken in through the interface 48, and the dimming rate is calculated from the result.
Step S19: the dimming ratio obtained in step S18, from which electricity amount command value i ₂ which is obtained in step S16, to calculate a new current command value i _3.
Step S20: a current command value _{i 3} obtained by the step S19, the digital-to-analog converter, or the PWM signal is smoothed, and a DC signal output to the step-down converter control IC 40, the process proceeds to step S23.

Step S21: a current command value _{i 2} obtained by the step S16 the digital-to-analog converter, or the PWM signal is smoothed, and a DC signal output to the step-down converter control IC 40, then proceeds to step S23.
Step S22: a current command value _{i 2} obtained by step S4 digital-to-analog converter, or the PWM signal is smoothed, and a DC signal output to the step-down converter control IC 40.
Step S23: It is determined whether 20 minutes have passed since the control loop started control or the accumulated time was updated. If it has elapsed, the process proceeds to step S24, and if not, the process proceeds to S25. Here, 20 minutes is the minimum unit time of the integration time, and may be a different value depending on the capacity of the program and the nonvolatile memory.
Step S24: Refer to the accumulated time already recorded from the non-volatile memory (integrated time storage means 52).

Step S25: If 20 minutes have not elapsed since the start of control or the accumulated time has been updated, a counter for counting 20 minutes is added, and the process returns to step S2.
Step S26: 20 minutes is added to the integration time obtained in step S24 to calculate a new integration time.
Step S27: The new integrated time obtained in step S25 is recorded in the nonvolatile memory (integrated time storage means 52).
Step S28: A counter for counting 20 minutes (minimum unit time) is initialized, and the process returns to step S2.
Thereafter, control is performed by looping again from S2 to S28. Further, not only the lamp voltage but also the lamp current may be recorded in the nonvolatile memory and handled in each step.
As described above, according to the electronic ballast of the present embodiment, it is automatically determined that the lamp has been replaced, and the integrated time for lamp lighting is initialized. There is no need to provide a device, and forgetting to initialize the accumulated time can be prevented.

The graph which showed an example of the time-dependent change of a lamp. 1 is a schematic configuration diagram of an electronic ballast according to an embodiment of the present invention. Explanatory drawing of the change of the lamp voltage with respect to elapsed time. Explanatory drawing of the lamp replacement determination method of this embodiment. Explanatory drawing of the modification of a lamp replacement | exchange determination method. The schematic block diagram of the modification of the electronic ballast concerning this embodiment. Explanatory drawing of the calculation method of the time-dependent characteristic of a lamp | ramp. The flowchart of the control process of an electronic ballast. The graph which showed electric current command value table T1. The graph which showed luminous flux correction factor table T2.

Explanation of symbols

10 Electronic ballast 12 AC power supply 12
14 lamp 16 power supply circuit system 18 lighting control circuit system 52 accumulated time storage means 54 lighting history storage means 56 determination means

Claims (5)

In an electronic ballast comprising an accumulated time storage means for storing the accumulated lighting time of the lamp, and controlling the lighting of the lamp based on the accumulated time,
Lighting history storage means for recording the lamp current value or voltage value at the time of stable lighting for each lighting opportunity;
Judges whether or not the lamp has been replaced by comparing the lamp current value or lamp voltage value at the time of previous lighting stored in the lighting history storage means with the lamp current value or lamp voltage value at the time of lighting this time. Determination means to perform,
With
An electronic ballast characterized in that when the determination means determines that the lamp has been replaced, the accumulated lighting time stored in the accumulated time storage means is initialized. The electronic ballast of claim 1, wherein
The lamp lighting device according to claim 1, wherein the determination unit starts the determination from a point in time when the lamp lighting integrated time has exceeded a predetermined time. The electronic ballast according to claim 1 or 2,
The determination means determines that the lamp has been replaced when the absolute value of the difference between the lamp current value or lamp voltage value at the previous lighting time and the lamp current value or lamp voltage value at the current lighting time is equal to or greater than a predetermined threshold value. An electronic ballast characterized by that. The electronic ballast of claim 3, wherein
The determination means is such that the absolute value of the difference between the previous lamp current or voltage and the lamp current value or lamp voltage value at the time of lighting this time is equal to or greater than a predetermined threshold value and is opposite to the temporal characteristics of the lamp used. An electronic ballast characterized in that it is determined that the lamp has been replaced when it is a change. The electronic ballast of claim 4, wherein
An electronic ballast comprising a time-dependent characteristic calculating means for calculating a time-dependent characteristic of a lamp from a lamp current value or a lamp voltage value at the time of each lighting stored in a lighting history storage means.

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