JP2009009788A - High-pressure discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp lighting device capable of prolonging time until turning off a high-pressure discharge lamp when instantaneous service interruption or instantaneous voltage drop of input power occurs. <P>SOLUTION: This high-pressure discharge lamp lighting device 100 lights a high-pressure discharge lamp 7 having a rectifier circuit 2 connected to commercial power, a step-up inverter 3, and a step-down inverter 4 including an FET Q41. The high-pressure discharge lamp lighting device 100 is characterized by including: a detection circuit 9 indirectly detecting the voltage of the commercial power; a control circuit 10 controlling the FET Q41 of the step-down inverter 4; and a power changeover part 10a arranged in the control circuit 10, and controlling the FET Q41 of the step-down inverter 4 to set the lamp current of the high-pressure discharge lamp 7 to 31-43% of the lamp current before the voltage detected by the detection circuit 9 is lowered below a predetermined value when the voltage detected by the detection circuit 9 is lowered below the predetermined value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lighting device for a high pressure discharge lamp such as a metal halide lamp. When an instantaneous power failure or instantaneous voltage drop of an input power source occurs, the lamp lighting maintenance time can be extended without increasing the capacitor capacity of the power circuit. The present invention relates to a high pressure discharge lamp lighting device.

  When the metal halide lamp is turned on in a steady state and then turned off, and then immediately turned on, it takes several minutes (4 to 7 minutes) to restart. Therefore, depending on the installation situation, there is a problem that a large area of the floor becomes a power failure state.

  FIG. 4 is a block diagram showing a schematic configuration of a conventional discharge lamp lighting device. In FIG. 4, 101 is a commercial power supply, 102 is a power switch, 103 is a rectifying and smoothing circuit, and includes a smoothing capacitor having a capacitance value equal to or higher than the normal design capacitance value. 104 is a chopper circuit that controls lamp power, 105 is a full-bridge inverter circuit that switches polarity, 106 is a starter, 107 is a discharge lamp such as a metal halide lamp, and 108 is an input voltage detection circuit that detects no-voltage during a power failure. The chopper circuit 104 is controlled by the detection signal.

In this discharge lamp lighting device, when a momentary power failure occurs, the input voltage detection circuit 108 detects a no-voltage at the time of the momentary power failure of the commercial power supply 101, and the chopper circuit 104 is dimmed with low lamp power. As a result, the large-capacity smoothing capacitor stored electrical energy of the rectifying and smoothing circuit 103 can maintain the lighting without turning off the discharge lamp 107 even when the power supply is cut off for a short time (see, for example, Patent Document 1). ).
JP-A-6-168788

  The conventional discharge lamp lighting device detects the no-voltage at the time of the instantaneous power failure of the power supply 101 by the input voltage detection circuit 108 and puts the chopper circuit 104 into a dimming state with a low lamp power, resulting in an instantaneous voltage drop (sag). On the other hand, there was a problem that it could not be handled.

  In addition, if the dimming control is performed by detecting the voltage before and after the rectifying and smoothing circuit 103 in order to cope with the instantaneous voltage drop, a complicated detection circuit is required to cover an irregular instantaneous voltage drop over a wide range. Is required. Even if a complicated detection circuit is installed, malfunctions such as flickering may occur.

  Furthermore, the conventional discharge lamp lighting device detects the no-voltage at the time of the instantaneous power failure of the power supply 101 by the input voltage detection circuit 108 and sets the chopper circuit 104 to a dimming state with low lamp power. There is a problem that there is no effect of maintaining the lighting without turning off the discharge lamp 107 or that the discharge lamp 107 is deteriorated.

  The present invention has been made to solve the above-described problems. When an instantaneous power failure or instantaneous voltage drop of the input power source occurs, the high pressure discharge lamp can be turned on to extend the time until the high pressure discharge lamp is turned off. An object is to provide an apparatus.

  A high pressure discharge lamp lighting device according to the present invention is a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp having a rectifier circuit connected to a commercial power source, a step-up inverter, and a step-down inverter including a switching element. A detection circuit that indirectly detects the voltage; a control circuit that controls the switching element of the step-down inverter; and a control circuit that is provided in the control circuit and that detects the voltage detected by the detection circuit falls below a predetermined voltage. And a power switching unit that controls the switching element of the step-down inverter so that the lamp current is 31 to 43% of the lamp current before the voltage detected by the detection circuit falls below a predetermined voltage. .

  In the high pressure discharge lamp lighting device according to the present invention, the rectifier circuit includes a first capacitor, and the detection circuit detects a voltage of the first capacitor.

  In the high pressure discharge lamp lighting device according to the present invention, the step-up inverter has a second capacitor, and the detection circuit detects the voltage of the second capacitor.

  In the high pressure discharge lamp lighting device according to the present invention, the switching element of the step-down inverter is controlled so that the lamp current of the high pressure discharge lamp becomes 31 to 43% of the steady state, so that the time until the high pressure discharge lamp is extinguished is extended. The high-pressure discharge lamp can be prevented from turning off and safety is improved.

Embodiment 1 FIG.
1 to 3 are diagrams showing Embodiment 1, FIG. 1 is a circuit diagram of a high pressure discharge lamp lighting device 100, FIG. 2 is a circuit diagram of a modified high pressure discharge lamp lighting device 100, and FIG. It is a figure which shows the relationship with the time until lamp extinction in an instantaneous power failure test.

  The configuration of the high pressure discharge lamp lighting device 100 will be described with reference to FIG. The rectifier circuit 2 is composed of a diode bridge composed of a diode D21, a diode D22, a diode D23, and a diode D24 that performs rectification by taking in AC power from the commercial power supply 1, and a capacitor 21 connected between both output terminals of the diode. Composed.

  The step-up inverter 3 includes an inductance L31 having one end connected to the output terminal of the high potential side of the rectifier circuit 2, a diode D31 having the other end connected to the anode of the inductance L31, a cathode of the diode D31, and a low potential side of the rectifier circuit 2. The output terminal is configured by a FET Q31 (field effect transistor) connected to the drain and the source, and a capacitor C31 connected between the cathode of the diode D31 and the low potential side output terminal of the rectifier circuit 2.

  The step-down inverter 4 includes a FET Q41 (an example of a switching element) to which a cathode and a drain of a diode D31 are connected, a diode D41 to which the cathode and an anode are connected to the source of the FET Q41 and the low-potential side output terminal of the rectifier circuit 2, The capacitor L41 is connected between the other end of the inductance L41 and the low-potential side output end of the rectifier circuit 2.

  The lighting circuit 5 includes a series-connected FETQ51 and FETQ52 connected in parallel to the capacitor C41, a series-connected FETQ53 and FETQ54 connected in parallel to the FETQ51 and FETQ52, and a start pulse generating circuit 6.

  The detection circuit 9 detects the voltage of the capacitor C21 of the rectifier circuit 2.

  During normal lighting, the control circuit 10 has a function of controlling the supply of predetermined DC power from the step-down inverter 4 to the lighting circuit 5 by duty control of the FET Q41 of the step-down inverter 4, and a function by the power switching unit 10a. Prepare.

  When the detection circuit 9 detects that the voltage of the capacitor C21 of the rectifier circuit 2 has dropped below a predetermined voltage, the power switching unit 10a controls the FET Q41 for a predetermined time with a duty control signal having a short ON period. To do.

  As shown in FIG. 2, when the detection circuit 9 detects that the voltage of the capacitor C31 of the step-up inverter 3 has dropped below a predetermined voltage, the power switching unit 10a uses the duty control signal with a short on period to enable the FET Q41. This control may be performed for a predetermined time.

  How long can the time from the momentary power failure of the high-pressure discharge lamp 7 to extinguish by controlling the lamp current of the high-pressure discharge lamp 7 by controlling the FET Q41 for a predetermined time with a duty control signal with a short ON period? An example of measurement is shown below.

  The high-pressure discharge lamp lighting device 100 of FIG. 1 or 2 changes the duty of the control signal of the FET Q41 at the momentary power interruption (output power of the step-down inverter 4) to control the lamp current of the high-pressure discharge lamp 7 to An instantaneous power failure test was performed, and the time until the high pressure discharge lamp 7 was extinguished was measured. The result is shown in FIG. The high pressure discharge lamp 7 used for the instantaneous power failure test is 100 W for the ceramic metal halide lamp (1), and the high pressure discharge lamp lighting device 100 is 100 W.

  As shown in FIG. 3, in the lamp (1), when the lamp current [%] immediately after the instantaneous power failure is 43%, the time from the instantaneous power failure to the lamp extinguishing [%] ] (The reference is the time from the momentary power failure when the inverter output is not controlled at the momentary power failure to the lamp extinction) is about 140% (the time from the momentary power interruption to the lamp extinction is about 80 ms). In addition, if the lamp current [%] immediately after the momentary power failure (% of the lamp current before the momentary power failure) is set to 18 [%], the time from the momentary power failure to the lamp extinguishing [%] (the standard is the output of the inverter at the momentary power failure) The time from the momentary power failure when the control is not performed until the lamp is extinguished) is about 100%, which is not improved.

  In the lamp (2), if the lamp current [%] immediately after the momentary power failure (%) (ratio to the lamp current before the momentary power failure) is set to 31 [%], the time from the momentary power failure to the lamp extinguishing [%] The time from the momentary power failure when the inverter output is not controlled to the lamp extinguishing) is about 150% (the time from the momentary power interruption to the lamp extinguishing is about 65 ms). If the lamp current [%] immediately after the momentary power failure (ratio to the lamp current before the momentary power failure) is set to 59 [%], the time from the momentary power failure to the lamp extinguishment [%] (the standard is the output of the inverter at the momentary power failure) The time from the momentary power failure when the control is not performed until the lamp is extinguished) is about 100%, which is not improved.

  In the lamp (3), when the lamp current [%] immediately after the momentary power failure (%) (ratio to the lamp current before the momentary power failure) is 56 [%], the time from the momentary power failure to the lamp extinguishing [%] The time from the momentary power failure when the inverter output is not controlled until the lamp is extinguished) is not improved at about 100%. Furthermore, if the lamp current [%] immediately after the momentary power failure (ratio to the lamp current before the momentary power failure) is set to 20 [%], the time from the momentary power failure to the lamp extinguishing [%] (the standard is the output of the inverter at the momentary power failure) The time from the momentary power failure when the control is not performed until the lamp is extinguished is about 60%, which is worse than when the output of the inverter during the momentary power failure is not controlled.

  From the above results, when the voltage of the capacitor C21 of the rectifier circuit 2 or the capacitor C31 of the booster inverter 3 detected by the detection circuit 9 falls below a predetermined voltage, the power switching unit 10a determines that the lamp current of the high-pressure discharge lamp 7 is By controlling the FET Q41 of the step-down inverter 4 so that the voltage of the capacitor C21 of the rectifier circuit 2 or the capacitor C31 of the step-up inverter 3 falls to 31 to 43% before dropping below a predetermined voltage, it is possible to prevent an instantaneous power failure or an instantaneous voltage drop. The time until the lamp is extinguished can be extended compared with the steady lighting.

  According to the power situation in Japan, the duration of the instantaneous voltage drop is 3 cycles of the maximum power supply frequency. Accordingly, the duration of the instantaneous voltage drop is a maximum of 60 ms at 50 Hz and a maximum of 50 ms at 60 Hz. In the present embodiment, as described above, since the lamp is not turned off for 65 to 80 ms after the occurrence of the instantaneous power failure or the instantaneous voltage drop, it is possible to cope with the instantaneous voltage drop in the power situation in Japan.

FIG. 3 shows the first embodiment, and is a circuit diagram of the high-pressure discharge lamp lighting device 100. FIG. 5 shows the first embodiment, and is a circuit diagram of a high-pressure discharge lamp lighting device 100 according to a modification. In the figure which shows Embodiment 1, the relationship between lamp current and the time until lamp extinction in an instantaneous power failure test is shown. It is a block diagram which shows schematic structure of the conventional discharge lamp lighting device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Commercial power supply, 2 Rectifier circuit, 3 Booster inverter, 4 Buck inverter, 5 Lighting circuit, 6 Start pulse generation circuit, 7 High pressure discharge lamp, 9 Detection circuit, 10 Control circuit, 10a Power switching part, 100 High pressure discharge lamp lighting device , 101 Commercial power supply, 102 switch, 103 rectification smoothing circuit, 104 chopper circuit, 105 full bridge inverter circuit, 106 starter, 107 discharge lamp, 108 input voltage detection circuit.

Claims (3)

In a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp having a rectifier circuit connected to a commercial power source, a step-up inverter, and a step-down inverter including a switching element,
A detection circuit for indirectly detecting the voltage of the commercial power supply;
A control circuit for controlling the switching element of the step-down inverter;
Provided in this control circuit, when the voltage detected by the detection circuit drops below a predetermined voltage, the lamp current of the high-pressure discharge lamp is reduced before the voltage detected by the detection circuit drops below a predetermined voltage. A high pressure discharge lamp lighting device comprising: a power switching unit that controls the switching element of the step-down inverter so as to be 31 to 43% of the lamp current.   The high pressure discharge lamp lighting device according to claim 1, wherein the rectifier circuit includes a first capacitor, and the detection circuit detects a voltage of the first capacitor.   2. The high pressure discharge lamp lighting device according to claim 1, wherein the step-up inverter has a second capacitor, and the detection circuit detects a voltage of the second capacitor.

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