JP2006049035A - Discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a discharge lamp lighting device in which lighting by a normal discharge lamp can be maintained by turning off only the discharge lamps abnormally discharged by causes such as the final stage of their lives among a plurality of discharge lamps when the plurality of the discharge lamps are lighted on by one inverter circuit. <P>SOLUTION: In the discharge lamp lighting device which is provided with the inverter circuit which converts a direct current voltage into a high frequency alternating current voltage, and the plurality of the discharge lamps are lighted on by output from this inverter circuit, this is provided with a plurality of choke coils serially-connected to every discharge lamp, a plurality of relays serially-connected to this choke coil and every series circuit of the discharge lamp, a plurality of discharge lamp connection detecting circuits which detect with or without of connection to the discharge lamp lighting device at every discharge lamp, a plurality of abnormal discharge detecting circuits which detect the abnormal discharge at every discharge lamp, and a control circuit which controls open-close of a relay contact based on the detected result of the discharge lamp detecting circuit and the abnormal discharge detecting circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a discharge lamp lighting device that uses a single inverter circuit to light a plurality of discharge lamps such as fluorescent lamps at a high frequency.

  In the conventional discharge lamp lighting device, when a plurality of discharge lamps are lit by a single inverter circuit, even if one of the plurality of discharge lamps is abnormally discharged at the end of its life, etc., the power of the discharge lamp increases due to abnormal discharge. For the purpose of protecting the inverter circuit from the inverter circuit, the inverter circuit is stopped and all the discharge lamps are extinguished (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 2001-273898 (page 4-5, FIG. 1)

In the conventional discharge lamp lighting device, the inverter circuit is stopped when an abnormal discharge occurs even at the end of its life, and the normal discharge lamp is extinguished even if other discharge lamps are normal. Depending on the situation, the light could not be obtained, which was inconvenient.
The present invention has been made to solve the above-described problems. When a plurality of discharge lamps are lit by a single inverter circuit, a discharge lamp that is abnormally discharged at the end of its life or the like among the plurality of discharge lamps. Thus, a discharge lamp lighting device capable of maintaining only normal discharge lamp lighting is obtained.

  In the discharge lamp lighting device according to the present invention, an inverter circuit that converts a DC voltage into a high-frequency AC voltage, a plurality of discharge lamps that are lit by an output from the inverter circuit, and a plurality of series connected to each discharge lamp Choke coil, a plurality of relays connected in series for each series circuit of the choke coil and the discharge lamp, and a plurality of discharge lamp connection detections for detecting the presence or absence of connection to the discharge lamp lighting device for each discharge lamp A circuit, a plurality of abnormal discharge detection circuits for detecting abnormal discharge for each discharge lamp, and a control circuit for controlling opening and closing of the relay contacts based on detection results of the discharge lamp detection circuit and the abnormal discharge detection circuit; , With.

  According to the present invention, when the abnormal discharge detection circuit detects an abnormal discharge of the discharge lamp while the inverter circuit is operating, the control circuit stops the operation of the inverter circuit, and the first predetermined By opening the contact of the relay corresponding to the discharge lamp that has detected abnormal discharge after the lapse of time, and operating the inverter circuit again after the second predetermined time has elapsed, the inverter circuit is stopped when abnormal discharge is detected. Therefore, only the discharge lamp with abnormal discharge can be turned off, and normal lighting of the discharge lamp can be maintained.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of a discharge lamp lighting device showing Embodiment 1 of the present invention, FIG. 2 is a time chart showing the operation of the discharge lamp lighting device at the time of turning on / off and power failure, and FIG. FIG. 4 is a time chart showing the operation when another discharge lamp is connected while one discharge lamp of the lighting device is lit. FIG. 4 shows another discharge when one discharge lamp of this discharge lamp lighting device is normally discharged. It is a time chart figure which shows the operation | movement when the electric lamp 6 became abnormal discharge.
In the figure, 1 is a power supply, 2 is a rectifier circuit, 3 is a smoothing capacitor, and 4 is an inverter circuit.

5 is a first choke coil, 6 is a first discharge lamp, 6a and 6b are electrodes of the first discharge lamp 6, 7 is a first starting capacitor, 8 is a first DC cut capacitor, The choke coil 5, the first discharge lamp 6 and the first DC cut capacitor 8 are connected in series.
9 is a second choke coil, 10 is a second discharge lamp, 10a and 10b are electrodes of a second discharge lamp, 11 is a second starting capacitor, 12 is a second DC cut capacitor, The choke coil 9, the second discharge lamp 10, and the second DC cut capacitor 12 are connected in series.

13 is a resistor, 14 is a resistor connected in parallel with the first starting capacitor 7, 15 is a resistor connected in parallel with the first DC cut capacitor 8, the resistor 13 to the first discharge lamp 6 from the smoothing capacitor 3. A DC voltage is applied through the electrode 6a, the resistor 14, the electrode 6b of the first discharge lamp 6, and the resistor 15. Similarly, 17 is a resistor connected in parallel with the second starting capacitor 11, 18 is a resistor connected in parallel with the second DC cut capacitor 12, the resistor 13 through the smoothing capacitor 3, and the second discharge lamp 10. A DC voltage is applied through the electrode 10a, the resistor 17, the electrode 10b of the second discharge lamp 10, and the resistor 18.

  20 is a first abnormal discharge detection circuit that detects abnormal discharge of the first discharge lamp 6, 21 is a second abnormal discharge detection circuit that detects abnormal discharge of the second discharge lamp 10, and 22 is the smoothing capacitor 3. This is a power failure detection circuit that monitors the voltage and detects a power failure of the power source 1. Reference numeral 23 denotes a first relay, and a contact of the first relay 23 is connected between the inverter circuit 4 and the first choke coil 5. Reference numeral 24 denotes a second relay, and a contact of the second relay 24 is connected between the inverter circuit 4 and the second choke coil 9. 25, the output signals of the first connection detection circuit 16, the second connection detection circuit 19, the first abnormal discharge detection circuit 20, the second abnormal discharge detection circuit 21 and the power failure detection circuit 22 are inputted, and the inverter circuit 4 The control circuit controls the oscillation of the first relay 23 and the second relay 24.

Next, the operation will be described.
The voltage supplied from the power source 1 is rectified by the rectifier circuit 2 and further smoothed by the smoothing capacitor 3. The DC voltage from the smoothing capacitor 3 is input to the inverter circuit 4, and this DC voltage is converted into a high-frequency AC voltage by the inverter circuit 4. The output of the inverter circuit 4 is choked via the contact of the first relay 23 and the series circuit of the choke coil 5, the first discharge lamp 6, the first DC cut capacitor 8 and the contact of the second relay 24. The coil 9, the second discharge lamp 10, and the second DC cut capacitor 12 are respectively supplied to a series circuit.

The first starting capacitor 7 is connected in parallel to the first discharge lamp 6 via the electrodes 6a and 6b in the first discharge lamp 6, forms a resonance circuit with the first choke coil 5, and the first discharge capacitor 6 When the electric lamp 6 is started, a high pressure is generated at both ends of the first capacitor 7 to operate the first discharge lamp 6 to be discharged.
Similarly, the second starting capacitor 11 is connected in parallel to the second discharge lamp 10 via the electrodes 10 a and 10 b in the second discharge lamp 10, and the second starting capacitor 11 is connected to the second choke coil 9. A resonant circuit is formed, and operates so as to generate a high pressure at both ends of the second capacitor 11 at the time of starting the second discharge lamp 10 to promote the discharge of the second discharge lamp 10.

  The first connection detection circuit 16 includes the resistor 13, the electrode 6 a of the first discharge lamp 6, the resistor 14, the electrode 6 b of the first discharge lamp 6, and the presence or absence of the closed circuit of the resistor 15. Detects connection / disconnection. That is, when the first discharge lamp 6 is connected, the resistor 13, the electrode 6 a of the first discharge lamp 6, the resistor 14, the electrode 6 b of the first discharge lamp 6, the resistor are applied by the voltage from the smoothing capacitor 3. A current flows through 15 paths, and a voltage is generated in the resistor 15. When the discharge lamp 6 is not connected, a closed circuit is not formed, and the voltage of the resistor 15 is not generated. The first connection detection circuit 16 detects the connection / disconnection of the first discharge lamp 6 by detecting the voltage across the resistor 15.

Similarly, the second connection detection circuit 19 detects whether the second discharge circuit 10 has a closed circuit of the resistor 13, the electrode 10a of the second discharge lamp 10, the resistor 17, the electrode 10b of the second discharge lamp 10, and the resistor 18. The connection / disconnection of the electric light 10 is detected. That is, when the second discharge lamp 10 is connected, the resistor 13, the electrode 10a of the second discharge lamp 10, the resistor 17, the electrode 10b of the second discharge lamp 10, A current flows through 18 paths to generate a voltage at the resistor 18. When the discharge lamp 10 is not connected, a closed circuit is not formed, and the voltage of the resistor 18 is not generated. The second connection detection circuit 19 detects the connection / disconnection of the second discharge lamp 10 by detecting the voltage across the resistor 18.

The first abnormal discharge detection circuit 20 monitors the discharge voltage when the first discharge lamp 6 is lit, and detects abnormal discharge when the discharge voltage is higher than the normal discharge voltage.
Similarly, the second abnormal discharge detection circuit 21 monitors the discharge voltage when the second discharge lamp 10 is lit, and detects abnormal discharge when the discharge voltage is higher than the normal discharge voltage.
The power failure detection circuit 22 monitors the voltage of the smoothing capacitor 3 and detects a power failure of the power source 1.

  The detection outputs of the first connection detection circuit 16, the second connection detection circuit 19, the first abnormal discharge detection circuit 20, the second abnormal discharge detection circuit 21, and the power failure detection circuit 22 are input to the control circuit 25, The control circuit 25 controls the oscillation of the inverter circuit 4 and the first relay 23 and the second relay 24 according to these inputs.

Next, the operation of the control circuit 25 will be described with reference to FIGS.
First, in the case where the first discharge lamp 6 and the second discharge lamp 10 are connected in advance to the discharge lamp lighting device and both the discharge lamps are normal, the control circuit 25 at the time of turning on / off the power supply 1 and at the time of power failure 2 will be described with reference to FIG. 2, (1) is an on / off state of the power supply 1, (2) is an output signal of the first connection detection circuit 16, (3) is an output signal of the second connection detection circuit 19, and (4) is the first (5) is the output signal of the second abnormality detection circuit 21, (6) is the output signal of the power failure detection circuit 22, (7) is the open / close state of the first relay 23, 8) shows the open / close state of the second relay 24, and (9) shows the oscillation state of the inverter circuit 4, respectively.

  In the control circuit 25, when the power supply 1 is turned on from off, the first connection detection circuit 16 detects the connection of the first discharge lamp 6 and closes the contact of the first relay 23. Similarly, the second connection detection circuit 19 detects the connection of the second discharge lamp 10 and closes the contact of the second relay 24. Thereafter, when the predetermined time T1 elapses, the inverter circuit 4 is controlled to start oscillating. When the inverter circuit 4 oscillates, the first discharge lamp 6 and the second discharge lamp 10 are turned on as described above. At this time, the detection of the first abnormal discharge detection circuit 20 and the second abnormal discharge detection circuit 21 assumes that no abnormal discharge is detected and is normal.

  Thereafter, when the power source 1 is turned off from on or when a power failure occurs, the power failure detection circuit 22 detects the power failure, and first, the control circuit 25 controls to stop the oscillation of the inverter circuit 4. Further, control is performed so that the contact points of the first relay 23 and the second relay 24 are opened after a lapse of T2 time after the oscillation of the inverter circuit 4 is stopped.

  Next, before the power source 1 is turned on, the first discharge lamp 6 is not connected, and when the power source 1 is turned on and the second discharge lamp 10 is lit, the first discharge lamp 6 is connected. The operation of the control circuit 25 will be described with reference to FIG. 3, (1) to (9) indicate the same signals or control contents as in FIG.

When the power supply 1 is turned on from the OFF state, the control circuit 25 detects that the first connection detection circuit 16 is not connected to the first discharge lamp 6 and maintains the contact of the relay 23 based on the detection result. At the same time, the second connection detection circuit 19 detects the connection of the second discharge lamp 10 and closes the contact of the second relay 24. Thereafter, when the predetermined time T1 elapses, the inverter circuit 4 is controlled to start oscillating.
Therefore, when the first discharge lamp 6 is connected while the second discharge lamp 10 is lit, the first connection detection circuit 16 detects the connection of the first discharge lamp 6, and the control circuit 25 detects the inverter circuit 4. Control to stop the oscillation. Further, the control is performed so that the contact of the first relay 23 is closed after the time T2 has elapsed since the oscillation of the inverter circuit 4 is stopped. Further, after the time T1 has elapsed, the oscillation of the inverter circuit 4 is restarted, and the first discharge lamp 6 and the second discharge lamp 10 are turned on.

The control circuit 25 also includes a relay 23 and a relay 24 corresponding to each discharge lamp even when the second discharge lamp 10 is not connected when the power supply 1 is turned on and the first discharge lamp 6 is connected. Are similarly controlled.
Further, when both the first discharge lamp 6 and the second discharge lamp 10 are not connected when the power source 1 is turned on, the contacts of the first relay 23 and the second relay 24 are kept open. The oscillation of the inverter circuit 4 also remains stopped. After that, if the first discharge lamp 6 or the second discharge lamp 10 or both are connected, the contacts of the first relay 23 and the second relay 24 are closed as shown in FIG. And the first discharge lamp 6 and the second discharge lamp 10 are turned on.

  Next, control when the first discharge lamp 6 causes abnormal discharge while the first discharge lamp 6 and the second discharge lamp 10 are normally discharged, and the first abnormal discharge detection circuit detects abnormal discharge. The operation of the circuit 25 will be described with reference to FIG. In FIG. 4, (1) to (9) indicate the same signals or control contents as in FIG.

When the first abnormal discharge detection circuit 20 detects the abnormal discharge of the first discharge lamp 6, the oscillation of the inverter circuit 4 is stopped, and then the contact of the first relay 23 is opened after a lapse of T2, and further T1 After the elapse of time, the oscillation of the oscillation circuit 4 is resumed. Thereafter, the series circuit of the first choke coil 5, the first discharge lamp 6 and the DC cut capacitor 8 is disconnected from the inverter circuit 4 by the first relay 23.
Similarly, when the second discharge lamp 10 is abnormally discharged, the series circuit of the second choke coil 9, the second discharge lamp 10 and the DC cut capacitor 12 is disconnected from the inverter circuit 4 by the second relay 24. become.

Here, as described with reference to FIGS. 2 to 4, the on / off control of the first relay 23 and the second relay 24 is switched after the inverter circuit 4 is stopped and a predetermined time has elapsed. That is, the first relay 23 and the second relay 24 open and close the contacts in a state where current is interrupted from the inverter circuit 4 (current is zero). Thereby, even when the first relay 23 and the second relay 24 are frequently turned on and off, it is possible to prevent the occurrence of failure such as welding of the relay contacts.
In the first embodiment, the case where two inverter lamps are lit by one inverter circuit has been described. However, the number of discharge lamps may be three or more, and the same number of relays or abnormalities as the number of discharge lamps. By providing the discharge detection circuit and the connection detection circuit, the same effect can be obtained.

As described above, the relay contacts are connected between the inverter circuit and the plurality of discharge lamps, and the connection state, discharge state, power supply presence / absence (power outage) of each discharge lamp is detected, and the relay is controlled by the control circuit. Thus, only the abnormal discharge lamp can be turned off, so that the normal discharge lamp can be kept on.
Further, the relay on / off control is performed after the inverter circuit is stopped and a predetermined time elapses. Therefore, even when the relay is frequently turned on / off, the occurrence of a failure such as welding of the relay contact can be prevented.

It is a circuit diagram of the discharge lamp lighting device which shows Embodiment 1 of this invention. It is a time chart figure which shows operation | movement of the discharge lamp lighting device which shows Embodiment 1 of this invention. It is a time chart figure which shows operation | movement of the discharge lamp lighting device which shows Embodiment 1 of this invention. It is a time chart figure which shows operation | movement of the discharge lamp lighting device which shows Embodiment 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Power supply, 4 Inverter circuit, 5 1st choke coil, 6 1st discharge lamp, 9 2nd choke coil, 10 2nd discharge lamp, 16 1st connection detection circuit, 19 2nd connection detection circuit , 20 first abnormal discharge detection circuit, 21 second abnormal discharge detection circuit, 22 power failure detection circuit, 23 first relay, 24 second relay, 25 control circuit.

Claims (5)

In a discharge lamp lighting device comprising an inverter circuit for converting a DC voltage into a high-frequency AC voltage and a plurality of discharge lamps that are lit by outputs from the inverter circuit, a plurality of choke coils connected in series for each discharge lamp A plurality of relays connected in series for each series circuit of the choke coil and the discharge lamp, and a plurality of discharge lamp connection detection circuits for detecting the presence or absence of connection to the discharge lamp lighting device for each discharge lamp, A plurality of abnormal discharge detection circuits that detect abnormal discharge for each of the discharge lamps, and a control circuit that controls opening and closing of the relay contacts based on detection results of the discharge lamp detection circuit and the abnormal discharge detection circuit. A discharge lamp lighting device that specializes in When the power source of the discharge lamp lighting device is turned on, the control circuit stops the inverter circuit and closes the contact of the relay corresponding to the discharge lamp whose connection state is detected by the discharge lamp connection detection circuit. The discharge lamp lighting device according to claim 1, wherein the inverter circuit is operated after a predetermined time. When the abnormal discharge detection circuit detects an abnormal discharge of the discharge lamp while the inverter circuit is in operation, the control circuit stops the operation of the inverter circuit, and after the first predetermined time has elapsed, 3. The discharge lamp lighting device according to claim 1, wherein a contact of a relay corresponding to the discharge lamp in which discharge is detected is opened, and the inverter circuit is operated again after a second predetermined time has elapsed. . The control circuit closes the contact of the relay for a predetermined time until the oscillation of the inverter circuit stops when the discharge lamp is turned off while the inverter circuit is in operation. The discharge lamp lighting device according to any one of claims 1 to 3. A power failure detection circuit for detecting a power failure of the power supply of the discharge lamp lighting device; and when the inverter circuit is operating and the power failure detection circuit detects a power failure, the control circuit oscillates the inverter circuit. The discharge lamp lighting device according to any one of claims 1 to 4, wherein the discharge lamp lighting device stops and closes the contact of the relay for a predetermined time or more.

Images