JP2001319794A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive stress from being added to circuit elements and the generation of going-out. SOLUTION: This is equipped with a discharge lamp DL, a chopper 1 connected to a DC power supply, an inverter 2 to convert this direct current electric power into an alternating current electric power and to supply the discharge lamp DL with it, an igniter electrode 3 to apply this high voltage pulse to the discharge lamp DL in a startup, a voltage detection part 4/current detection part 5 to detect an output voltage/current of the chopper 1, a voltage detection part to detect this input voltage, and a control part 10 which controls a chopper 1 to regulate the output and controls the oscillating frequency of the inverter 2, and which keeps the oscillating frequency at a low frequency during a predetermined period as a DC phase section and which makes the oscillating frequency to a high frequency after a predetermined period has passed. The control part 10 is constituted so that the lamp current will be limited by a control of the chopper 1 in case the voltage of the power supply DC falls in the DC phase section and so that the oscillating frequency will be made to be a lower frequency than that of a stationary time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device, for example, a vehicle discharge lamp lighting device.

[0002]

2. Description of the Related Art FIG. 6 shows a configuration diagram of a conventional discharge lamp lighting device, and FIGS. 7 and 8 show operation waveform diagrams of the discharge lamp lighting device of FIG.

[0003] The discharge lamp lighting device shown in FIG. 6 is used, for example, mounted on a vehicle, and is connected to a power source DC such as a 12 V battery of the vehicle. That is, the power supply DC is configured using a switching element such as an FET via the capacitor C0 (step-up).
The input of the chopper 1 is connected. A discharge lamp DL such as a high-intensity discharge (HID) lamp is provided on the output side of the chopper 1, and the output of the chopper 1 and the discharge lamp D
L, FETs Q1 to Q1 of a full bridge circuit configuration
An inverter 2 comprising an inverter 4 is provided. Further, between the output of the inverter 2 and the discharge lamp DL, a high-voltage pulse for starting lighting is generated and applied to the discharge lamp DL to break down the discharge lamp DL. An igniter 3 is provided to shift to arc discharge and start discharge. Further, the output of the chopper 1 is constituted by resistors R41 to R43, and the output voltage of the chopper 1 or the discharge lamp DL
And a resistor R5. The output current of the chopper 1 or the discharge lamp D
And a current detector 5 for detecting the L lamp current. Further, the inputs of the chopper 1 include resistors R61 to R61.
63, a voltage detecting unit 6 for monitoring the voltage of the power supply DC is provided, and a control unit 10PA is provided.

However, each of the FETs Q1 to Q4 has a parasitic diode functioning as a feedback diode. Further, this type of discharge lamp lighting device is also used for various uses other than the vehicle, and in some cases, an AC power supply is used for a power supply DC part, and an AC-DC converter is used for a chopper 1 part.

The control unit 10PA controls the on / off of a switching element (not shown) of the chopper 1, adjusts the output of the chopper 1, and controls the oscillation frequency of the inverter 2. In the example of FIG. It comprises an arithmetic unit 11, a chopper control unit 12, a driver 13, and an inverter control unit 14.

As shown in FIG. 7, at the time of startup, the power calculation unit 11 determines the time from the start of the lamp current Idl to the elapse of a predetermined time after the start of the lamp current Idl based on the time from the previous turn-off to the start time t0. Lamp current I in DC phase section
s and the oscillation frequency fs are determined, and after the end of the DC phase section, the voltage detection unit 4 and the current detection unit 5
Is used to calculate the amount of power to be supplied to the discharge lamp DL. To explain an example of this calculation, a calculation is performed to determine a lamp current for making the electric energy obtained from both the detection results of the voltage detection unit 4 and the current detection unit 5 into a predetermined electric energy by feedback control. Note that, instead of the time from the previous turn-off time to the start time t0, a lamp state such as a temperature or a lamp voltage of the discharge lamp DL may be used.

[0007] The chopper control unit 12 controls on / off of the switching element of the chopper 1 so that the output of the chopper 1 becomes the level determined by the power calculation unit 11.
The output of the chopper 1 is adjusted.

The driver 13 is connected to each FET of the inverter 2
Is turned on and off. In the DC phase section, the inverter control unit 14 alternately turns on / off the set of FETs Q1 and Q4 and the set of FETs Q2 and Q3 via the driver 13 at the oscillation frequency fs determined by the power calculation unit 11. On the other hand, after the end of the DC phase section, the oscillation frequency fs is set to a higher oscillation frequency fp.
To the pair of FETs Q1, Q4 and FETs Q2, Q
3 are alternately turned on / off via the driver 13.

Here, if the time from the previous light extinguishing time to the starting time t0 is such that the discharge lamp DL is sufficiently adjusted to the ambient temperature to such an extent that the starting performance is not affected, FIG. As shown in FIG. 8A, the lamp current Is and the oscillation frequency fs in the DC phase section are set to the lamp current Is1 and the oscillation frequency fs1, respectively.
As shown in (b), when the above-mentioned starting is restarted, the lamp current Is and the oscillation frequency fs in the DC phase section are set to the lamp current Is2 and the oscillation frequency fs2, respectively. However, Is1> Is2 and fs1> fs2, and these are set to values that satisfy Is1 / (2 × fs1) = Is2 / (2 × fs2).

According to the discharge lamp lighting device configured as described above, after the end of the DC phase section, the oscillation frequency becomes f
Switching to fp higher than s enables stable and smooth lighting of the discharge lamp DL.

In addition, at the time of starting, the oscillation frequency and the lamp current in the DC phase section are determined according to the time from the previous turn-off time to the start time, so that the life of the discharge lamp DL can be extended. As a result, it becomes possible to prevent flashing at the time of starting.

Japanese Patent Application Laid-Open No. H11-297486 discloses a discharge lamp lighting device capable of increasing the starting voltage when starting the discharge lamp and improving the starting performance.

[0013]

However, in the discharge lamp lighting apparatus shown in FIG. 6, the lamp current and the oscillation frequency in the DC phase section are limited only by the state of the lamp and the time from the last turn-off to the start. And the determined lamp current flows in the circuit regardless of the voltage level of the power supply DC, and there is a risk that circuit elements will be excessively stressed. FIG. 9 shows the relationship between the power supply voltage and the input current.

Further, when only the lamp current in the DC phase section is limited, there is a problem that the extinction easily occurs at the time of polarity inversion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a discharge lamp lighting device capable of preventing an excessive stress from being applied to a circuit element and preventing occurrence of extinguishing. And

[0016]

According to a first aspect of the present invention, there is provided a discharge lamp lighting apparatus, comprising: a discharge lamp, a DC power supply connected to an input and having a variable output voltage level, and a DC power supply. An inverter that converts DC power from a power supply into AC power and supplies it to a discharge lamp, and controls a DC power supply to adjust the output and control the oscillation frequency of the inverter. A control unit that sets the oscillation frequency to a low frequency until a predetermined time as a DC phase section has elapsed since the start of the flow, and sets the oscillation frequency to a high frequency after the predetermined time has elapsed. When the voltage of the power supply connected to the input of the DC power supply drops, the DC power supply is controlled to limit the lamp current, and the oscillation frequency is set to a frequency lower than the steady state. And wherein the Rukoto.

According to a second aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the control unit determines that a voltage of a power supply connected to an input of the DC power supply becomes lower than a certain voltage in a DC phase section. In the case, D
The magnitude of the lamp current in the C phase section is compared with the magnitude of the lamp current in the DC phase section set when the voltage is equal to or lower than a certain voltage. The lighting control of the discharge lamp is performed by using the magnitude and the oscillation frequency of the lamp current in the DC phase section set in the following cases.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the control unit is configured such that, in a DC phase section, a voltage of a power supply connected to an input of a DC power supply becomes lower than a certain voltage. In the case, D
A comparison is made between the magnitude of the lamp current in the C phase section and the magnitude of the lamp current in the DC phase section set according to the voltage of the power supply. It is characterized in that the lighting control of the discharge lamp is performed using the magnitude and the oscillation frequency of the lamp current in the DC phase section set according to the voltage.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the magnitude of the lamp current in the DC phase section at the time of initial start is Is1, and the oscillation frequency is f.
When the magnitude of the lamp current in the DC phase section in the restart is Is2 and the oscillation frequency is fs2, the control unit satisfies Is1> Is2, and Is1 / (2 × fs1) = I
It is characterized in that control is performed so as to be s2 / (2 × fs2).

The invention described in claim 5 is the invention according to claim 2 or 4
In the discharge lamp lighting device according to
The magnitude of the lamp current in the C phase section is Is, the oscillation frequency is fs, the magnitude of the lamp current in the DC phase section set at a certain voltage or less is Iv1, and the oscillation frequency f
When v1 is set, the control unit calculates Is / (2 × fs) = I
It is characterized in that control is performed so that v1 / (2 × fv1).

The invention according to claim 6 is the invention according to claim 3 or 4.
In the discharge lamp lighting device according to
When the magnitude of the lamp current in the C phase section is Is and the oscillation frequency is fs, and the magnitude of the lamp current in the DC phase section set according to the power supply voltage is Iv2 and the oscillation frequency fv2, Is / (2 × fs) = Iv2 / (2 × fv2).

[0022]

1 is a block diagram of a discharge lamp lighting device according to a first embodiment of the present invention, and FIG. 2 is an operation waveform diagram of the discharge lamp lighting device of FIG. Next, the first embodiment will be described.

The discharge lamp lighting device shown in FIG. 1 comprises a capacitor C0, a chopper 1, an inverter 2, an igniter 3,
The voltage detector 4, the current detector 5, and the voltage detector 6 are shown in FIG.
And a control unit 10 as a difference from the conventional discharge lamp lighting device.

The control unit 10 controls on / off of the switching elements of the chopper 1 to adjust the output of the chopper 1 and controls the oscillation frequency of the inverter 2. The power calculation unit 11, the chopper control unit 12, a driver 13 and an inverter control unit 14 are provided in the same manner as the conventional discharge lamp lighting device shown in FIG. 6, and a difference from the conventional discharge lamp lighting device is a comparator 15, a DC phase power calculation unit. 16 and switching unit 17
It has.

The comparator 15 compares the voltage level of the power supply DC (more precisely, the level of the divided voltage) detected by the voltage detection unit 6 with a predetermined reference voltage level. If the level is higher than the level of the reference voltage, the output level is set high, and if the level is lower, the output level is set low.

The DC phase power calculation section 16 operates during the DC phase section, and the comparator 1 operates during the DC phase section.
5, the lamp current Iv1 smaller than the lamp current Is and the oscillation frequency fv1 lower than the oscillation frequency fs are changed to Is / (2 × f, as shown in FIG. 2).
s) = Iv1 / (2 × fv1). At this time, the lamp current Iv1 and the oscillation frequency fv1 defined by the DC phase power calculation unit 16 are both one value.

The switching unit 17 compares the lamp current Is in the DC phase section determined by the power calculation unit 11 with the lamp current Iv1 from the DC phase power calculation unit 16, and determines that the lamp current Is is larger than the lamp current Iv1. For example, the lamp current Is used in the chopper control unit 12 and the oscillation frequency fs used in the inverter control unit 14 are switched to the lamp current Iv1 and the oscillation frequency fv1 from the DC phase power calculation unit 16, respectively. Alternatively, the lamp current Iv1
If is not output, the switching is not performed, and the chopper control unit 12 and the inverter control unit 14 use the lamp current Is and the oscillation frequency fs, respectively.

Next, the control unit 1 which is a feature of the first embodiment will be described.
The operation by 0 will be described. In the DC phase section,
When the voltage of the power supply DC decreases, the lamp current Is used in the chopper control unit 12 and the inverter control unit 14
Is switched to the lamp current Iv1 and the oscillation frequency fv1 from the DC phase power calculation unit 16, respectively. On the other hand, when the voltage of the power supply DC is stable without lowering, the chopper control unit 12 and the inverter control unit 14 use the lamp current Is and the oscillation frequency fs determined by the power calculation unit 11, respectively.

As described above, when the voltage of the power supply DC decreases, the lamp current Is is limited to the lamp current Iv1,
It is possible to prevent an excessive stress from being applied to the circuit element, and to stabilize the discharge of the discharge lamp DL by switching the oscillation frequency fs to the oscillation frequency fv1 so that the frequency is lower than the steady state. In addition, it is possible to prevent the occurrence of extinction during polarity reversal.

In the first embodiment, the lamp current Is and the oscillating frequency fs in the DC phase section are determined by the time from the last turn-off time to the start-up time. However, the present invention is not limited to this. Instead, the configuration may be determined by the state of the lamp, such as the temperature of the discharge lamp DL, the lamp voltage or the lamp current immediately after startup.

FIG. 3 is a configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention, FIG. 4 is an output waveform diagram of the DC phase power calculation unit of FIG. 3, and FIG. 5 is a diagram of the discharge lamp lighting device of FIG. The operation of the second embodiment will be described below with reference to operation waveform diagrams.

The discharge lamp lighting device shown in FIG. 3 comprises a capacitor C0, a chopper 1, an inverter 2, an igniter 3,
The voltage detection unit 4, the current detection unit 5, and the voltage detection unit 6
In addition to being provided in the same manner as in the first embodiment, a difference from the first embodiment is that a control unit 20 is provided.

The control section 20 controls the on / off of the switching elements of the chopper 1 to adjust the output of the chopper 1 and controls the oscillation frequency of the inverter 2. The power calculation section 11, the chopper control section 12, the driver 13, the inverter control unit 14 and the switching unit 17
In addition to being provided in the same manner as in the first embodiment, the present embodiment is different from the first embodiment in that a capacitor C25 and a DC phase power calculator 26 are provided.

The capacitor C25 smoothes the voltage of the power supply DC detected by the voltage detector 6. The DC phase power calculation unit 26 operates during the DC phase section, and calculates the lamp current Iv2 and the oscillation frequency fv2 according to the level of the voltage across the capacitor C25, as shown in FIG.
The output is a value satisfying s / (2 × fs) = Iv2 / (2 × fv2). At this time, the lamp current Iv1 and the oscillation frequency fv1 defined by the DC phase power calculation unit 16 change continuously according to the level of the voltage across the capacitor C25. If the voltage of the power supply DC is equal to or higher than the rated voltage (12 V) or a level at which stress on components does not increase, the lamp current and the oscillation frequency are output from the DC phase power calculation unit 26 even in the DC phase section. There may be no configuration.

Next, the control unit 2 which is a feature of the second embodiment
The operation by 0 will be described. In the DC phase section,
When the voltage of the power supply DC is lower than the rated voltage, the lamp current Is used in the chopper control unit 12 and the oscillation frequency fs used in the inverter control unit 14 increase in DC phase according to the level of the voltage across the capacitor C25. The current is switched to the lamp current Iv2 and the oscillation frequency fv2 output from the power calculator 26. On the other hand, when the voltage of the power supply DC is stable at the rated voltage without lowering, the chopper control unit 12 and the inverter control unit 14 use the lamp current Is and the oscillation frequency fs determined by the power calculation unit 11, respectively. You.

As described above, when the voltage of the power supply DC decreases, the lamp current Is is limited to the lamp current Iv2 corresponding to the level of the voltage between both ends of the capacitor C25, thereby preventing an excessive stress from being applied to the circuit elements. By switching the oscillation frequency fs to an oscillation frequency fv2 corresponding to the level of the voltage between both ends of the capacitor C25 and lowering the oscillation frequency fs from the steady state, the discharge of the discharge lamp DL can be stabilized. It is possible to prevent the disappearance of time.

[0037]

As is apparent from the above description, according to the first aspect of the present invention, a discharge lamp, a DC power supply connected to an input and having a variable output voltage level, and a DC power supply from the DC power supply. An inverter that converts the DC power into AC power and supplies it to the discharge lamp, and controls the DC power supply to adjust its output and controls the oscillation frequency of the inverter. A control unit that sets the oscillation frequency to a low frequency until a predetermined time as a section elapses, and sets the oscillation frequency to a high frequency after the predetermined time elapses. If the voltage of the connected power supply drops, the DC power supply is controlled to limit the lamp current and the oscillation frequency is set to a lower frequency than in the steady state. In the meantime, when the voltage of the power supply connected to the input of the DC power supply drops, by controlling the DC power supply to limit the lamp current, it is possible to prevent the circuit element from being subjected to excessive stress, By setting the oscillation frequency to be lower than that in the steady state, the discharge of the discharge lamp can be stabilized, so that the occurrence of extinction during polarity reversal can be prevented.

According to a second aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the control unit includes a DC power supply.
In the phase section, when the voltage of the power supply connected to the input of the DC power supply falls below a certain voltage, the magnitude of the lamp current in the DC phase section determined at the time of steady state and the DC phase section set when the voltage is below a certain voltage When the lamp current in the DC phase section determined in the steady state is larger, the magnitude and the oscillation frequency of the lamp current in the DC phase section set at a certain voltage or less are used. Since the lighting control of the discharge lamp is performed, it is possible to prevent an excessive stress from being applied to the circuit element, and to prevent the extinction from occurring at the time of polarity inversion.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the control unit includes:
In the phase section, when the voltage of the power supply connected to the input of the DC power supply becomes lower than a certain voltage, the DC phase section set according to the magnitude of the lamp current and the power supply voltage in the DC phase section determined in the steady state. When the lamp current in the DC phase section determined in the steady state is larger, the magnitude and the oscillation frequency of the lamp current in the DC phase section set according to the power supply voltage are used. Since the lighting control of the discharge lamp is performed, it is possible to prevent an excessive stress from being applied to the circuit element, and to prevent the extinction from occurring at the time of polarity inversion.

According to the fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, D
When the magnitude of the lamp current in the C phase section is Is1 and the oscillation frequency is fs1, and the magnitude of the lamp current in the DC phase section in restart is Is2 and the oscillation frequency is fs2,
The control unit satisfies Is1> Is2 and satisfies Is1 / (2 × fs
1) Since control is performed so that = Is2 / (2 × fs2),
The discharge lamp can be suitably turned on.

According to a fifth aspect of the present invention, in the discharge lamp lighting device according to the second or fourth aspect, the magnitude of the lamp current in the DC phase section in a steady state is Is, the oscillation frequency is fs, and the voltage is equal to or lower than a certain voltage. When the magnitude of the lamp current in the DC phase section set at the time of (1) is Iv1 and the oscillation frequency is fv1, the control unit calculates Is / (2 × f
s) = Iv1 / (2 × fv1)
Stress on components at low voltage can be reduced, and the discharge of the discharge lamp can be stabilized to make it difficult for the lamp to go out.

According to a sixth aspect of the present invention, in the discharge lamp lighting device according to the third or fourth aspect, the magnitude of the lamp current in the DC phase section in a steady state is Is, the oscillation frequency is fs, and the power supply voltage is DC set according to
When the magnitude of the lamp current in the phase section is Iv2 and the oscillation frequency is fv2, Is / (2 × fs) = Iv2 / (2 × f
Since control is performed so as to satisfy v2), it is possible to reduce stress on components at low voltage, stabilize the discharge of the discharge lamp, and make it difficult for extinction to occur.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 3 is a configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 4 is an output waveform diagram of a DC phase power calculator of FIG. 3;

5 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 6 is a configuration diagram of a conventional discharge lamp lighting device.

7 is an operation waveform diagram of the discharge lamp lighting device of FIG.

8 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 9 is a diagram showing a relationship between a power supply voltage and an input current.

[Explanation of symbols]

 DL discharge lamp DC power supply 1 chopper (DC power supply) 2 inverter 3 igniter 4 voltage detection unit 5 current detection unit 6 voltage detection unit 10, 20 control unit 11 power calculation unit 12 chopper control unit 13 driver 14 inverter control unit 15 comparator 16, 26 DC phase power calculation unit 17 Switching unit C25 capacitor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Miki Kotani 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. 72) Inventor Shinji Okamoto 1048 Kazuma Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd.

Claims (6)

[Claims] 1. A discharge lamp, a DC power supply connected to an input and having a variable output voltage level, an inverter for converting DC power from the DC power supply to AC power and supplying the AC power to the discharge lamp, and controlling the DC power supply To adjust the output and control the oscillation frequency of the inverter,
A control unit that sets the oscillation frequency to a low frequency until a predetermined time as a DC phase section elapses after the lamp current starts flowing at the time of starting, and sets the oscillation frequency to a high frequency after the predetermined time elapses, wherein the control unit includes: In the DC phase section, when the voltage of the power supply connected to the input of the DC power supply decreases, the DC power supply is controlled to limit the lamp current, and the oscillation frequency is set to a frequency lower than the steady state. Discharge lamp lighting device. 2. The control section according to claim 1, wherein, when the voltage of the power supply connected to the input of the DC power supply falls below a certain voltage in the DC phase section, the control section determines the magnitude of the lamp current in the DC phase section determined in a steady state. Compare the lamp current in the DC phase section set when the voltage is lower than the voltage, and if the lamp current in the DC phase section determined in the steady state is larger, the DC phase section set when the voltage is lower than a certain voltage. 2. The discharge lamp lighting device according to claim 1, wherein the lighting control of the discharge lamp is performed using the magnitude of the lamp current and the oscillation frequency. 3. The controller according to claim 1, wherein in a DC phase section, when a voltage of a power supply connected to an input of the DC power supply becomes lower than a certain voltage, a magnitude of a lamp current and a power supply in a DC phase section determined in a steady state. And the magnitude of the lamp current in the DC phase section set according to the voltage of
If the lamp current in the DC phase section determined during the steady state is larger, the DC current set according to the power supply voltage
The discharge lamp lighting device according to claim 1, wherein the lighting control of the discharge lamp is performed using the magnitude of the lamp current and the oscillation frequency in the phase section. 4. The magnitude of the lamp current in the DC phase section at the time of the first start is Is1, the oscillation frequency is fs1, and the magnitude of the lamp current in the DC phase section in the restart is I2.
When s2 and the oscillation frequency are fs2, the control unit calculates Is1
> Is2, and Is1 / (2 × fs1) = Is2 / (2 × f
The discharge lamp lighting device according to claim 1, wherein the control is performed so as to satisfy s2). 5. The magnitude of the lamp current in the DC phase section in a constant state is Is, the oscillation frequency is fs, and the magnitude of the lamp current in the DC phase section set at a certain voltage or lower is Iv1, and the oscillation frequency fv1 is 5. The discharge lamp lighting device according to claim 2, wherein the control unit performs control so that Is / (2 × fs) = Iv1 / (2 × fv1). 6. The magnitude of the lamp current in the DC phase section in a steady state is Is, the oscillation frequency is fs, the magnitude of the lamp current in the DC phase section set according to the power supply voltage is Iv2, and the oscillation frequency fv2 is Then, Is / (2
5. The discharge lamp lighting device according to claim 3, wherein the control is performed so that (* fs) = Iv2 / (2 * fv2).