JP2009140862A - High-pressure discharge lamp lighting device, light source device, and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent heating of a high-pressure discharge lamp heating device in dimming operation. <P>SOLUTION: The high-pressure discharge lamp lighting device which is used in a light source device in which a cooling output is weakened in dimming includes a step-down converter which restricts input from a DC power supply part and outputs to the high-pressure discharge lamp by a switching operation, a detection part to detect a lamp current and voltage of the high-pressure discharge lamp, a light-control control part to output a dimming signal, and a converter control part which controls the switching operation according to the lamp power or a lamp current and the dimming signal. The converter control part consists of a PWM control part which determines a duty ratio of the switching operation so that the lamp output or the lamp current may be a full lighting set value or a light-control set value according to the dimming signal, a frequency control part which determines the switching frequency according to the dimming signal, and a driver which generates a gate signal of a switching element according to the duty ratio and the switching frequency. The switching frequency in dimming is constructed to be lower than that in full lighting. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high pressure discharge lamp lighting device, and more particularly to a technique for preventing an excessive temperature rise of a high pressure discharge lamp lighting device due to a lamp voltage drop during dimming operation.

In recent years, for example, 0.15 mg / mm ³ or more of mercury and 1 × 10 ⁻⁷ mol of halogen per 1 mm ³ are sealed in a discharge vessel made of quartz glass, and the distance between a pair of electrodes is 1 mm or more and 1.5 mm or less. In high-pressure mercury discharge lamps, high-pressure discharge lamp lighting devices having a circuit configuration shown in FIG. 7 are becoming widespread. This high pressure discharge lamp lighting device is composed of a DC power source 1, a step-down chopper circuit 2, a full bridge circuit 3, an igniter circuit 4, a dimming control circuit 9 and a control circuit 10, and the igniter circuit 4 includes an igniter control circuit 7 and is controlled. The circuit 10 includes a chopper control circuit 5 and a full bridge control circuit 6.

  The DC power source 1 only needs to rectify and smooth a commercial AC power source, and generally includes a power factor correction circuit and the like. Further, the lighting circuit includes a voltage detection circuit including resistors R1 and R2 for detecting a voltage (hereinafter referred to as “lamp voltage”) of a high pressure mercury discharge lamp (hereinafter referred to as “high pressure discharge lamp”) La, and a high pressure discharge lamp La. A current detection circuit including a resistor R3 for detecting a flowing current (hereinafter referred to as “lamp current”) is provided.

  After the chopper control circuit 5 controls the duty ratio of the switching element Q1 (eg, MOSFET) of the step-down chopper circuit 2, the output current of the DC power supply 1 is converted into an appropriate value, and then the output current is converted to the full bridge circuit 3 Is output.

The full bridge control circuit 6 alternately turns on the switching elements Q2 and Q5 and Q3 and Q4 of the full bridge circuit 3, and a low frequency rectangular wave current of about 50 Hz to 1 kHz is output to the high pressure discharge lamp La.
The igniter control circuit 7 applies a voltage of several hundred volts to the primary winding N1 of the transformer T1 before starting the high-pressure discharge lamp La, thereby applying a high voltage pulse (several kV to several tens kV) to the secondary winding N2. ) To start the high-pressure discharge lamp La. After starting the high-pressure discharge lamp La, the igniter control circuit 7 stops its operation.

  The dimming control circuit 9 receives a dimming signal from the outside of the lighting device (the dimming signal oscillation circuit 8), converts the signal appropriately, and outputs the signal to the chopper control circuit 5. When receiving the dimming signal, the chopper control circuit 5 controls the duty ratio of the switching element Q1 (decreases the on-duty width) so that the lamp power becomes the set dimming power. As a result, the power of the high-pressure discharge lamp La (hereinafter referred to as “lamp power”) is reduced and dimming is performed.

  The cooling fan control unit 11a increases or decreases the output of the cooling fan 11b according to the dimming signal as will be described later. The cooling fan control unit 11a and the cooling fan 11b are not included in the high pressure discharge lamp lighting device.

FIG. 8 shows the lamp power and the circuit loss of the high-pressure discharge lamp lighting device with respect to the lamp power characteristics of, for example, a total light power of 150 W and a dimming power of 125 W. In FIG. 8, the horizontal axis indicates the lamp voltage, the vertical axis indicates the lamp power and the circuit loss, the lamp power Pf at the time of all-light lighting and the circuit loss Lf of the high-pressure discharge lamp lighting device are indicated by dotted lines, and the lamp power Pd at the time of dimming. The circuit loss Ld is indicated by a solid line.
In the example of FIG. 8, constant current control of 2.5 A is performed until the lamp power reaches a predetermined total light power and a predetermined dimming power, and in the 150 W all light mode, the constant power starts from a lamp voltage of 60 V or more. In the 125W dimming mode, the constant power control is performed from the lamp voltage of 50V or more.

By the way, in recent years, a reduction in noise of a cooling fan has become a problem in a projector. Then, as shown in the circuit loss of FIG. 8, the circuit loss of the high pressure discharge lamp lighting device is generally lower when the dimming operation is performed than when the all-light operation is performed, so the output of the cooling fan is reduced. Noise reduction by this has been studied.
JP 2003-264094 A

Here, the phenomenon inside the high-pressure discharge lamp La will be described. In the high-pressure discharge lamp La, tungsten, which is an electrode material heated at the time of lighting, evaporates, and is combined with halogen or the like present in the arc tube to form a tungsten compound.
This tungsten compound diffuses from the vicinity of the tube wall to the vicinity of the tip of the electrode by convection or the like, and is decomposed into tungsten atoms at a high temperature portion. Tungsten atoms become cations by ionizing in the arc. Both electrodes that are lit with alternating current repeat the anode and cathode at each lighting frequency, but when this cathode is operating, the cations in the arc are attracted to the cathode side by the electric field, and are deposited at the tips of both electrodes. This suppresses an increase in lamp voltage by forming protrusions.

  However, since the lamp current of the high-pressure discharge lamp La is lower than that when rated (all light) is lit when dimming is lit, the amount of tungsten evaporation of the electrode is also reduced. The protrusions grow too much and the lamp voltage tends to be lower than the lamp voltage at the time of rated lighting. Therefore, as shown in FIG. 8, usually, with a certain lamp voltage value as a boundary, constant power control is performed when the lamp voltage is higher than that, and constant current control is performed when the lamp voltage is lower than that. The value of the lamp voltage is about 60 V for all-light lighting, and for dimming lighting, it is common to set it to about 50 V in consideration of the lamp voltage drop due to the growth of electrode protrusions.

By the way, the circuit loss of the high pressure discharge lamp lighting device cannot be generally said to be sufficiently small compared to the loss at the time of dimming.
When the lamp voltage is in the range of 60 V or more, the circuit loss Ld at the time of dimming lighting is smaller than the circuit loss Lf at the time of all light lighting corresponding to the lamp power. On the other hand, when the lamp voltage is 50V to 60V, the difference between both circuit losses is reduced, and when the lamp voltage is 50V or less, there is almost no difference between both circuit losses. Accordingly, in the vicinity of the lamp voltage of 50 V and lower than that at the time of dimming, the output of the cooling fan is lowered even though the circuit loss is not significantly different from that at the time of all light. Therefore, when the lamp voltage is low during dimming, the high pressure discharge lamp lighting device may not be sufficiently cooled.

2A shows a switching waveform (voltage-current waveform) and switching loss waveform of the switching element Q1 that controls the power supplied to the high-pressure discharge lamp La in all-light lighting, and FIG. 2B shows a similar waveform in dimming lighting.
Only the duty ratio of the switching element Q1 is controlled by the chopper control circuit 5, and the switching frequency f1 is the same for rated (all light) lighting and dimming lighting. Normally, the step-down chopper circuit 2 is designed in accordance with the all-optical output having a large output, and the coil specifications (core size, inductance, etc.) are determined in accordance with the maximum value of the current flowing through the coil L1. At that time, in order to reduce the size of the coil 1, it has been desirable to set the frequency f1 high within the capability of the switching element Q1 or the chopper control circuit 5.

  As shown in FIGS. 2A and 2B, in the case of dimming lighting, if the lamp voltage is the same as that at the time of all light, the switching loss is reduced by the amount of current flowing through the switching element (hereinafter referred to as “switching current”). It is running low. On the contrary, near or below the lower limit of the constant power control, the switching current is almost the same in both the all-light setting and the dimming setting, so that it can be seen that the switching loss is also almost equal.

  Therefore, if the output of the cooling fan is lowered during dimming lighting to reduce the noise of the cooling fan during projector operation, the combination of the high pressure discharge lamp with a low lamp voltage during dimming lighting will There is a case where the generated heat cannot be cooled down and reaches the operating temperature of the temperature protection circuit. In the worst case, the high pressure discharge lamp lighting device may be destroyed.

  Further, in Patent Document 1, when the lamp voltage is lowered, the lamp voltage is increased by forcibly melting the electrode protrusions by changing the duty (energization period) of the lamp current waveform of the low frequency rectangular wave or increasing the lamp current. However, in this case, since stress is applied to the electrode, it is not necessarily a desirable method in consideration of the lamp life.

  Therefore, at the time of dimming, a circuit loss is used in order to suppress heat generation of the high pressure discharge lamp lighting device while making the input power to the high pressure discharge lamp La the initially set dimming power and reducing noise by reducing the fan output. Needs to be reduced as compared with the prior art.

  A first aspect of the present invention is a high pressure discharge lamp lighting device used inside a light source device in which a cooling output is weakened at the time of dimming than at the time of all light, and includes a DC power supply unit (1), at least one switching element The step-down converter (20) that restricts the input from the DC power supply by the switching operation and outputs it to the high-pressure discharge lamp, the detection unit (25) that detects the lamp current and the lamp voltage of the high-pressure discharge lamp, and outputs the dimming signal A dimming control unit (90) and a converter control unit (50) for controlling a switching operation in accordance with the lamp power or the lamp current calculated from the lamp current and the lamp voltage and the dimming signal are provided. PWM control unit that determines the duty ratio in the switching operation so that the lamp power or the lamp current becomes the all-light setting value or the dimming setting value according to the optical signal ( 01), a frequency control unit (502) for determining a switching frequency in the switching operation according to the dimming signal, and a gate signal of the switching element according to the duty ratio determined by the PWM control unit and the switching frequency determined by the frequency control unit A high-pressure discharge lamp lighting device configured such that a switching frequency when receiving a dimming signal (during dimming) is lower than a switching frequency during all light in a frequency control unit. is there.

In the first aspect, the switching frequency at the time of dimming is determined in the converter control unit under the duty ratio determined by the PWM control unit and within a range in which the peak current value flowing through the switching element does not exceed a predetermined value. It was made to be.
Here, the predetermined value is the maximum value of the peak current value that flows through the switching element during all light.
Further, when the high pressure discharge lamp is a high pressure mercury discharge lamp in which 0.15 mg / mm ³ or more of mercury is sealed in a discharge vessel made of quartz glass and the distance between the pair of electrodes is 1 mm or more and 1.5 mm or less. The switching frequency during all light and dimming was set in the range of 70 kHz to 110 kHz.

  According to a second aspect of the present invention, there is provided a high-pressure discharge lamp lighting device, a high-pressure discharge lamp, a reflecting mirror to which the high-pressure discharge lamp is attached, a high-pressure discharge lamp lighting device and a housing containing the reflecting mirror, The light source device includes a cooling fan that cools the inside of the housing.

  A third aspect of the present invention is a method for controlling a high pressure discharge lamp lighting device used inside a light source device in which the cooling output is weaker than that in all light during dimming, and the high pressure discharge lamp lighting device is at least A step-down converter (20) for limiting the input from the DC power supply unit by the switching operation of one switching element and outputting it to the high-pressure discharge lamp, a detection unit (25) for detecting the lamp current and the lamp voltage of the high-pressure discharge lamp, And a converter control unit (50) for controlling the switching operation, and the method is (A) a step in which the converter control unit determines the presence or absence of a dimming signal, and (B2) no dimming signal (in the case of all light). The converter control unit switches the switching element, the lamp power calculated from the lamp current and the lamp voltage, or the duty ratio at which the lamp current becomes the all-light set value, and the first The step of switching at the wave number; and (C2) if there is a dimming signal (in the case of dimming), the converter control unit switches the switching element, the duty ratio at which the lamp power or lamp current becomes the dimming set value, and In this configuration, switching is performed at a second frequency lower than the first frequency.

  A fourth aspect of the present invention is a method for controlling a light source device (100) including a cooling fan (71) and a high pressure discharge lamp lighting device (60) cooled directly or indirectly by the cooling fan, A step-down converter (20) for the high pressure discharge lamp lighting device to limit the input from the DC power supply unit by the switching operation of at least one switching element and output to the high pressure discharge lamp, the lamp current and the lamp voltage of the high pressure discharge lamp A detection unit (25) for detecting, and a converter control unit (50) for controlling a switching operation, wherein the cooling fan has a cooling fan control unit (70). A step in which the control unit determines the presence or absence of a dimming signal; (B) if there is no dimming signal (in the case of all light), (B1) the cooling fan control unit selects the first cooling fan A step of rotating at the number of rotations, and (B2) the converter control unit switches the switching element to the lamp power or lamp current calculated from the lamp current and the lamp voltage at a duty ratio at which the total light set value is reached, and the first frequency And (C) when there is a dimming signal (in the case of dimming), (C1) a step in which the cooling fan control unit rotates the cooling fan at a second rotational speed lower than the first rotational speed. And (C2) a configuration in which the converter control unit switches the switching element at a second frequency lower than the first frequency at a duty ratio at which the lamp power or the lamp current becomes a dimming set value. did.

In the third and fourth aspects, step (C2) includes (C21) a step of determining a duty ratio at which the lamp power or the lamp current becomes a dimming setting value, and (C22) a current flowing through the switching element is equal to or less than a predetermined value. And (C23) determining the second frequency from the duty ratio and the on-duty width.
When the high pressure discharge lamp is a high pressure mercury discharge lamp in which 0.15 mg / mm ³ or more of mercury is sealed in a discharge vessel made of quartz glass and the distance between the pair of electrodes is 1 mm or more and 1.5 mm or less, The first and second frequencies were in the range of 70 kHz to 110 kHz.

  According to the high pressure discharge lamp lighting device and the control method of the same device of the present invention, the power supplied to the high pressure discharge lamp is controlled by controlling the duty ratio of the switching operation of the step-down converter, and at the time of dimming of the switching element Since the switching frequency is reduced within a range in which the peak current value does not exceed a predetermined value (for example, the peak current value when all the lights are lit), the number of times the transistor is turned on and off per unit time is reduced. The power loss at can be reduced. Then, by limiting the peak current of the switching element to a range that does not exceed the value of the peak current at the time of all-light lighting, it is possible to prevent magnetic flux saturation of the coils constituting the step-down converter.

  Thereby, at the time of light control, the heat input to the high-pressure discharge lamp is set to the initially set light control power, and the heat generation of the high-pressure discharge lamp lighting device can be suppressed while achieving noise reduction by reducing the fan output. Naturally, it is possible to ensure an optimal design for the operating conditions of the step-down converter in all light.

Embodiments of the present invention will be described below.
FIG. 1A shows a block diagram of a high pressure discharge lamp lighting device according to the present invention. As shown in the figure, the apparatus includes a DC power supply unit 1, a step-down converter 20 that converts an input from the DC power supply unit 1 into a current of a high-pressure discharge lamp La by a switching operation of at least one switching element Q, and outputs a lamp current. And a detection unit 25 that detects the lamp voltage, an output unit 35 that receives an output from the step-down converter 20 and performs a starting operation of the high-pressure discharge lamp La, a lamp current waveform adjustment, a dimming control unit 90 that outputs a dimming signal, And a converter control unit 50 that controls the operation of the switching element Q in accordance with the lamp power or lamp current calculated from the lamp current and the lamp voltage and the dimming signal.

  The step-down converter 20 may be a buck converter (step-down chopper circuit) as shown in FIG. 1C described later, or various step-down converters such as an insulating flyback converter and a forward converter can be applied. That is, the input power supply is turned on / off by at least one switching element, the energy of the coil or transformer is charged / discharged by the switching operation, rectified by a diode as necessary, and the output is smoothed by a capacitor to produce a DC output. Anything you want to do.

  Since the output unit 35 is characterized by the configuration and operation of the converter control unit 50 (chopper control circuit 51) described later, any power conversion / power application method in the output unit 35 may be used. . For example, when the high-pressure discharge lamp La is an AC lighting lamp, the output unit 35 may be configured by a full bridge circuit as in an embodiment described later. When the high-pressure discharge lamp La is a DC lighting lamp, the step-down converter 20 is used. The output may be applied without AC conversion. In addition, the AC conversion means is also shown in the embodiment that performs AC conversion by a full bridge circuit, but the AC conversion method is not limited to this, and other methods such as push-pull may be used.

  FIG. 1B shows details of the converter control unit 50. The converter control unit 50 determines the duty ratio of the switching element Q so that the lamp power or the lamp current becomes the all-light setting value or the dimming setting value according to the dimming signal, and according to the dimming signal A frequency control unit 502 that determines the switching frequency of the switching element Q, and a driver 503 that generates a gate signal of the switching element Q according to the duty ratio determined by the PWM control unit 501 and the switching frequency determined by the frequency control unit 502 Including.

FIG. 1C shows a specific circuit configuration as an embodiment of the present invention. In this figure, the step-down converter 20 is the same as the step-down chopper circuit 2 as in FIG. 7, the resistors R1, R2 and R3 are used as the detection circuit 25, and the output circuit 35 is the same as the full bridge circuit 3 and igniter as in FIG. The circuit 4 is employed, and the dimming control circuit 9 similar to that shown in FIG. The chopper control circuit 51 and the full bridge control circuit 6 are included in the control circuit 10. Since the parts other than the chopper control circuit 51 are the same as those of the conventional example shown in FIG.
Note that the chopper control circuit 51 and the converter control unit 50 differ only in name and have substantially the same configuration and function.

  In the conventional example, the chopper control circuit 5 controls only the duty ratio of the switching element Q1, and as a result, the switching frequency is constant at f1 in all light and dimming, whereas in the present invention, The chopper control circuit 51 controls not only the duty ratio of the switching element Q1, but also the switching frequency by the frequency control unit 502.

In FIG. 1C, in the PWM control unit 501, the lamp power obtained by multiplying the lamp current or the lamp current and the lamp voltage matches the all-light setting value / the dimming setting value according to the presence / absence of the dimming signal. In addition, the duty ratio d1 / d2 of the switching element Q1 is determined.
In the frequency control unit 502, the switching frequency is determined to be f1 / f2 according to the presence / absence of the dimming signal. Here, the most basic feature of the present invention is that the switching frequency f2 during dimming is lower than the switching frequency f1 during all light.
The driver 503 applies a gate signal determined by the determined duty ratio d1 / d2 and the switching frequency f1 / f2 to the gate of the switching element Q1.

FIG. 2C shows a switching waveform (voltage-current waveform) and a switching loss waveform during dimming of the switching element Q1 of the high pressure discharge lamp lighting device according to the present invention.
As a result, if the loss per switching is about the same or less, the switching loss can be reduced as a whole by reducing the number of times of switching.

  When the switching frequency of the switching element Q1 is lowered, it is necessary that the peak value Ip of the switching current does not exceed a predetermined value (for example, the peak value in all light). As will be appreciated by those skilled in the art, the selection of the coil L1 of the step-down chopper circuit is usually performed so as to achieve an optimum design at the rated output (all light), more strictly, the maximum peak current at all light. The design is made in consideration of the value Ipmax. Accordingly, when the current peak value Ip exceeds the maximum peak current value Ipmax, the coil L1 is saturated, and when it is lower than that, the ability of the coil L1 is not fully utilized.

  That is, it is necessary to lower the switching frequency f2 in a range where the current peak value Ip does not exceed the designed maximum value Ipmax, and more preferably, the switching frequency f2 is lowered until the current peak value Ip approaches the maximum value Ipmax. Is desirable.

There are several methods for obtaining the current peak value Ip. On the other hand, the slope of the switching current waveform is determined by the inductance of the coil L1, and the direct current component that is slightly added at the moment when the current starts to flow is calculated by each parameter on the circuit. The current peak value Ip can be calculated. Such a calculation table may be provided in the chopper control circuit 51 (for example, the frequency control unit 502). Thereby, the current peak value Ip can be controlled by controlling the ON width.
Alternatively, as shown in FIG. 1C, the switching current is detected by a detection unit such as a resistor R4, and the detected current peak value Ip does not exceed the maximum value Ipmax under the duty ratio determined by the PWM control unit 501. The frequency controller 502 may lower the switching frequency within the range.

  Thus, by limiting the current peak value Ip to a range that does not exceed the maximum value Ipmax, the magnetic flux saturation of the coil L1 can be prevented even if the switching frequency is lowered during dimming. Since this does not affect the operating conditions of the step-down chopper circuit 2 in all light, an optimum design for all light is also ensured.

FIG. 3 is a diagram showing lamp power and circuit loss with respect to the lamp voltage of the high pressure discharge lamp lighting device of the present invention in comparison with FIG. 8 of the conventional example. The solid line in FIG. 3 represents the lamp power Pd during dimming lighting and the circuit loss Ld _A of the high pressure discharge lamp lighting device of the present invention, and the broken line represents the circuit loss Ld of the conventional example. Specifically, this is when the switching frequency is reduced until the peak current of the switching element Q1 at the time of dimming becomes the same as the peak current at the time of rated (all light) lighting, and the lamp voltage is around 50V where the loss is greatest Circuit loss is improved by about 14%.

And it is preferable to limit the switching frequency of the switching element Q1 at the time of all light lighting and the light control lighting to 70 kHz to 110 kHz. FIG. 4 shows the results of measuring the presence or absence of an acoustic resonance phenomenon for each frequency in a high-pressure mercury discharge lamp used for a projector or the like. For the measurement, 0.15 mg / mm ³ or more of mercury and 1 × 10 ⁻⁷ mol of halogen per 1 mm ³ are sealed in a discharge vessel, and the distance between the pair of electrodes is 1 mm or more and 1.5 mm or less. A discharge lamp was used.

  The horizontal axis of FIG. 4 is the switching frequency of the switching element Q1, and the ripple current of this frequency component is superimposed on the low frequency rectangular wave current of the high pressure discharge lamp La. The vertical axis represents the ripple current content with respect to the effective value of the lamp current of the high-pressure discharge lamp La. The ripple current amount represents the inductance value of the coil L1 of the step-down chopper circuit 2, the capacitance of the capacitor C1, and the pulse transformer of the igniter circuit 4. It is determined by the inductance value of the secondary winding N2 of T1. The black portion in FIG. 4 is a region where a so-called acoustic resonance phenomenon in which the arc becomes unstable is confirmed. As shown in the figure, the region between 70 kHz and 110 kHz is a stable region where no acoustic resonance phenomenon occurs even if the ripple current increases. Whether or not the acoustic resonance phenomenon occurs is determined by the relationship between the bulb shape of the high-pressure discharge lamp and the frequency component included in the ripple current, and the frequency at which the phenomenon occurs is specific to the lamp type.

  FIG. 5 shows an embodiment in which the present invention is applied to a light source device such as a projector. The light source device 100 is rotated by the high pressure discharge lamp lighting device 60 described with reference to FIG. 1A, the reflector 61 to which the high pressure discharge lamp La is attached, the housing 62 containing the high pressure discharge lamp lighting device 60, and the cooling fan control unit 70. A cooling fan 71 whose number is controlled is provided. In addition, the figure is a schematic illustration of the embodiment, and the dimensions, arrangement, and the like are not as illustrated. Then, a projector is configured by appropriately arranging a video system member or the like (not shown) in the housing 62. In addition, 8 is the dimming signal oscillation circuit described above, 50 is a converter control unit, 90 is a dimming control unit, and these connections may be wired or wireless. Although not shown, it is assumed that the power supply to each component is appropriately performed.

  As described above, since the high pressure discharge lamp lighting device that generates less heat during dimming is built in, the reliability of the high pressure discharge lamp lighting device is ensured even if the fan output is reduced to reduce noise during dimming. . Therefore, a low noise and highly reliable light source device can be obtained.

FIG. 6A is a flowchart showing a control method of the light source device 100 of FIG.
In step S100, lighting is started. It is assumed that all the lights are turned on at this time. That is, in step S101, the cooling fan controller 70 sets the rotation speed of the cooling fan 71 to r1, and in step S102, the converter controller 50 sets the switching frequency of the switching element Q to f1.
In step S110, the dimming control unit 90 and the cooling fan control unit 70 detect the presence or absence of the dimming signal from the dimming signal generation circuit 8, and return to step S101 if no dimming signal is detected. Then, the process proceeds to step S121.
In step S121, the cooling fan controller 70 reduces the rotational speed of the cooling fan 71 from r1 to r2, and in step S122, the converter controller 50 reduces the frequency of the switching element Q from f1 to f2.
As a result, noise reduction of the light source device and temperature rise suppression (particularly in the high pressure discharge lamp lighting device) are achieved.

  Note that if only steps S100, S102, S110, and S122 of the flowchart of FIG. 6A are connected, the flowchart of the control method of the high-pressure discharge lamp lighting device shown in FIG. 1A or 1C is established.

FIG. 6B shows the details of step S122 in the flowchart of FIG. 6A.
In step S201, the PWM control unit 501 determines the duty ratio d2 so that the lamp current or the lamp power becomes the dimming setting value.
In step S202, the frequency control unit 502 determines an on-duty width T2on at which the switching current is equal to or less than a predetermined value.
In step S203, the switching frequency f2 is calculated and determined from the duty ratio d2 and the on-duty width T2on.
As a result, the magnetic flux saturation of the coils used in the step-down converter 20 can be prevented, and the characteristics of the high-pressure discharge lamp lighting device designed for all light can be fully utilized during dimming.

It is a block diagram of the high pressure discharge lamp lighting device of the present invention. It is a figure which shows the detail of the block diagram of the high pressure discharge lamp lighting device of this invention. It is a figure which shows the circuit structure of the high pressure discharge lamp lighting device of this invention. It is a figure explaining the circuit structure of the high pressure discharge lamp lighting device of the present invention. It is a figure which shows the switching waveform and switching loss waveform of a switching element at the time of all-light lighting of a high pressure discharge lamp lighting device. It is a figure which shows the switching waveform and switching loss waveform of the switching element at the time of the light control lighting of the conventional high pressure discharge lamp lighting device. It is a figure which shows the switching waveform and switching loss waveform of the switching element at the time of the light control lighting of the high pressure discharge lamp lighting device in this invention. It is a figure showing lamp electric power and circuit loss to lamp voltage of a high pressure discharge lamp lighting device of the present invention. It is a figure showing the acoustic resonance phenomenon of a high pressure mercury lamp. It is a figure of the light source device of this invention. It is a flowchart which shows the control method of the light source device of this invention. It is a flowchart which shows the control method of the light source device of this invention. It is a figure which shows the circuit structure of the high pressure discharge lamp lighting device of this invention. It is a figure showing the lamp electric power with respect to the lamp voltage of a conventional high pressure discharge lamp lighting device, and a circuit loss.

Explanation of symbols

1. 1. DC power supply 2. Step-down chopper circuit 3. Full bridge circuit Igniter circuits 5, 51. 5. Chopper control circuit 6. Full bridge control circuit 7. Igniter control circuit 8. Dimming signal oscillation circuit Dimming control circuit 10. Control circuit 20. Step-down converter 25. Detection unit 35. Output unit 50. Converter control unit 60. High pressure discharge lamp lighting device 70. Cooling fan control unit 71. Cooling fan 90. Dimming control unit 100. Light source device 501. PWM control unit 502. Frequency control unit 503. Driver La. High pressure discharge lamp L1. Coils Q, Q1. Switching elements R1, R2, R3, R4. resistance

Claims (9)

It is a high pressure discharge lamp lighting device used inside the light source device in which the cooling output is weaker than that in all light during dimming,
A direct current power supply unit (1), a step-down converter (20) for restricting an input from the direct current power supply unit by a switching operation of at least one switching element and outputting to the high pressure discharge lamp, and a lamp current and a lamp voltage of the high pressure discharge lamp A detection unit (25) for detecting, a dimming control unit (90) for outputting a dimming signal, and the switching according to the lamp power calculated from the lamp current and the lamp voltage or the lamp current and the dimming signal A converter control unit (50) for controlling the operation;
The converter controller is
A PWM control unit (501) for determining a duty ratio in the switching operation so that the lamp power or the lamp current becomes an all-light setting value or a dimming setting value according to the dimming signal;
A frequency control unit (502) that determines a switching frequency in the switching operation according to the dimming signal, and the switching element according to a duty ratio determined by the PWM control unit and a switching frequency determined by the frequency control unit A driver (503) for generating a gate signal of
The high-pressure discharge lamp lighting device configured so that a switching frequency when a dimming signal is received (during dimming) is lower than a switching frequency during all light in the frequency control unit.   2. The high pressure discharge lamp lighting device according to claim 1, wherein, in the converter control unit, a peak value of a current flowing through the switching element does not exceed a predetermined value under a duty ratio determined by the PWM control unit. A high pressure discharge lamp lighting device in which a switching frequency at the time of dimming is determined.   3. The high pressure discharge lamp lighting device according to claim 2, wherein the predetermined value is a maximum value of a peak current value flowing through the switching element during all light. 2. The high pressure discharge lamp lighting device according to claim 1, wherein the high pressure discharge lamp has 0.15 mg / mm ³ or more mercury sealed in a discharge vessel made of quartz glass, and a distance between a pair of electrodes is 1 mm or more. A high-pressure mercury discharge lamp of 5 mm or less,
A high pressure discharge lamp lighting device having a switching frequency of 70 kHz to 110 kHz at the time of all light and dimming.   The high-pressure discharge lamp lighting device according to claim 1, the high-pressure discharge lamp, a reflecting mirror to which the high-pressure discharge lamp is attached, the high-pressure discharge lamp lighting device and a housing containing the reflecting mirror, and the inside of the housing are cooled. A light source device having a cooling fan. A method for controlling a high pressure discharge lamp lighting device used inside a light source device in which a cooling output is weaker than that in all light during dimming, wherein the high pressure discharge lamp lighting device is controlled by a switching operation of at least one switching element. A step-down converter (20) for limiting the input from the DC power supply unit to output to the high-pressure discharge lamp, a detection unit (25) for detecting the lamp current and lamp voltage of the high-pressure discharge lamp, and controlling the switching operation A converter controller (50), the method comprising:
(A) the converter control unit determining the presence or absence of a dimming signal;
(B2) When there is no dimming signal (in the case of all light), the converter control unit sets the switching element, the lamp power calculated from the lamp current and the lamp voltage, or the lamp current becomes the all light setting value. A step of switching at a first frequency with a duty ratio; and (C2) if there is a dimming signal (in the case of dimming), the converter control unit controls the switching element, and the lamp power or lamp current adjusts. A method comprising a step of switching at a second frequency lower than the first frequency at a duty ratio that becomes an optical set value. A method of controlling a light source device (100) comprising a cooling fan (71) and a high pressure discharge lamp lighting device (60) cooled directly or indirectly by the cooling fan, the high pressure discharge lamp lighting device comprising: A step-down converter (20) for limiting the input from the DC power supply by a switching operation of at least one switching element and outputting to the high-pressure discharge lamp, and a detection unit (25) for detecting the lamp current and lamp voltage of the high-pressure discharge lamp And a converter controller (50) for controlling the switching operation, the cooling fan having a cooling fan controller (70), and the method includes:
(A) the cooling fan control unit and the converter control unit determining the presence or absence of a dimming signal;
(B) When there is no dimming signal (in the case of all light),
(B1) the cooling fan control unit rotates the cooling fan at a first rotation speed; and (B2) the converter control unit causes the switching element to calculate the lamp power calculated from the lamp current and the lamp voltage. Or a step of switching at the first frequency at a duty ratio at which the lamp current becomes an all-light set value and (C) a dimming signal (in the case of dimming),
(C1) the cooling fan control unit rotates the cooling fan at a second rotational speed lower than the first rotational speed; and (C2) the converter control unit converts the switching element into the lamp power or lamp. A method comprising a step of switching at a second frequency lower than the first frequency at a duty ratio at which the current becomes a dimming set value. The method according to claim 5 or 6, wherein the step (C2) comprises:
(C21) determining a duty ratio at which the lamp power or lamp current becomes a dimming setting value;
(C22) a step of determining an on-duty width at which a current flowing through the switching element is equal to or less than a predetermined value; and (C23) a step of determining the second frequency from the duty ratio and the on-duty width. 7. The method according to claim 5, wherein the high-pressure discharge lamp has 0.15 mg / mm ³ or more of mercury enclosed in a discharge vessel made of quartz glass, and a distance between a pair of electrodes is 1 mm or more and 1.5 mm or less. High pressure mercury discharge lamp
The method wherein the first and second frequencies are in the range of 70 kHz to 110 kHz.

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