JP2010218734A - Electrodeless discharge lamp lighting device and luminaire - Google Patents

Abstract

An electrodeless discharge lamp lighting device and a lighting fixture capable of setting the start preparation time to an appropriate length with respect to the start time.
A start preparation operation P1 in which the amplitude of the output voltage to the induction coil is set to a value that is not so small that the electrodeless discharge lamp does not light up and is not 0 is performed for a predetermined start preparation time, and then the electrodeless discharge lamp In order to start lighting, a starting operation P2 for relatively increasing the amplitude of the output voltage is performed. Further, it is determined whether or not the electrodeless discharge lamp is lit during the starting operation P2. If the lighting of the electrodeless discharge lamp is not determined even if the starting operation P2 continues for a predetermined starting time, an output is output. The protection operation P4 to be stopped is started. At the start of the start operation P2, a sweep operation for gradually increasing the amplitude of the output voltage is performed. Furthermore, the start preparation time and the start time are each measured based on the clock signal of the oscillation unit.
[Selection] Figure 1

Description

  The present invention relates to an electrodeless discharge lamp lighting device and a lighting fixture using the electrodeless discharge lamp lighting device.

  Conventionally, an electrodeless discharge lamp lighting device for lighting an electrodeless discharge lamp in which a discharge gas is sealed in a bulb made of a light-transmitting material such as glass has been provided (for example, Patent Document 1 and Patent Document 2). This type of electrodeless discharge lamp lighting device generates a high-frequency electromagnetic field in a bulb of an electrodeless discharge lamp by supplying high-frequency AC power to an induction coil arranged close to the electrodeless discharge lamp. It is. When an arc discharge is generated in the bulb of the electrodeless discharge lamp by the high frequency electromagnetic field, the excited discharge gas emits ultraviolet rays. A fluorescent material is applied to the inner surface of the bulb of the electrodeless discharge lamp, and the ultraviolet light is converted into visible light by the fluorescent material, whereby the electrodeless discharge lamp emits light.

  As this type of electrodeless discharge lamp lighting device, there is one provided with a DC power supply unit that outputs DC power, and an inverter unit that converts the DC power output from the DC power supply unit into high-frequency AC power and supplies it to the induction coil is there. The DC power supply unit is composed of a switching power supply and is feedback controlled so as to maintain the output voltage constant. The inverter unit includes a resonance unit that forms a resonance circuit together with the induction coil, and a switching unit that periodically switches the connection between the DC power supply unit and the resonance unit. The frequency of the operation of the switching unit, that is, the output of the inverter unit AC power is output to the induction coil according to the relationship between the frequency (hereinafter referred to as “operation frequency”) and the resonance frequency of the resonance circuit. The inverter unit is feedback controlled so as to supply predetermined power to the induction coil.

  Furthermore, after starting the start preparation operation for reducing the amplitude of the output voltage of the inverter unit (hereinafter referred to as “voltage amplitude”) to such an extent that the electrodeless discharge lamp is not lit at the start, Start the starting operation to increase the amplitude to the extent necessary for the lighting of the electrodeless discharge lamp, and if the lighting of the electrodeless discharge lamp is not detected even if the starting operation is continued for a predetermined starting time, the voltage amplitude is reduced. There is also provided an electrodeless discharge lamp lighting device that shifts to a protective operation for protecting a circuit (see, for example, Patent Document 2).

  According to the above electrodeless discharge lamp lighting device, since the change in the impedance of the load circuit formed by the induction coil and the electrodeless discharge lamp is gradual compared with the case where the start preparation operation is not performed, the direct current during the start operation is reduced. Since the output voltage of the power supply unit is stabilized and overshoot due to feedback control is suppressed in the output power of the inverter unit, electrical stress applied to the circuit components can be suppressed.

JP 2005-158464 A Japanese Patent Laid-Open No. 2005-158459

  Here, the impedance of the load circuit is higher during the starting operation than when the electrodeless discharge lamp is steadily lit, but the DC power supply is usually designed assuming that the electrodeless discharge lamp is steadily lit. However, if the design is assumed to be during the start-up operation, it is necessary to use more expensive and larger components, leading to an increase in manufacturing cost and an increase in size.

  And, in the above conventional electrodeless discharge lamp lighting device, if the starting time is too long, the impedance of the load circuit becomes high during the starting operation, so that the output voltage of the DC power supply section gradually decreases, Since the electrodeless discharge lamp cannot be stably lit before the start of the protection operation, useless electrical stress is applied to the circuit components.

  The start-up time that can maintain the output voltage of the DC power supply unit to the extent that the electrodeless discharge lamp can be stably lit can be increased to some extent by increasing the start-up preparation time, but the start-up time is possible. The starting time and the starting preparation time when it is made as long as possible vary depending on the ambient temperature, circuit component characteristic variation and aging, and are not constant. Further, if the start preparation time is excessively lengthened, it takes time to turn on the electrodeless discharge lamp.

  The present invention has been made in view of the above-mentioned reasons, and an object thereof is to provide an electrodeless discharge lamp lighting device and a lighting fixture capable of setting the start preparation time to an appropriate length with respect to the start time. It is in.

  According to the first aspect of the present invention, there is provided an induction coil disposed close to the electrodeless discharge lamp, a DC power supply unit that outputs a DC power comprising a switching power supply, and a resonance unit and a DC power supply unit that form a resonance circuit together with the induction coil. An inverter unit that has a switching unit that periodically switches connection to the unit and converts DC power output from the DC power source unit to AC power and supplies the AC coil to the induction coil; and an oscillation unit that generates a periodic clock signal And a feedback control of the DC power supply unit so that the output voltage of the DC power supply unit becomes a predetermined target voltage, and a control unit that feedback-controls the frequency of operation of the switching unit in the inverter unit. Start preparation operation that sets the amplitude of the output voltage to the induction coil so that the amplitude of the electrodeless discharge lamp is small and non-zero After performing the start preparation time, in order to start the operation of the electrodeless discharge lamp, a start operation is performed in which the amplitude of the output voltage from the inverter unit to the induction coil is relatively large, and the electrodeless discharge is performed during the start operation. Judgment is made on whether or not the lamp is lit. If the lighting of the electrodeless discharge lamp is not determined even if the starting operation continues for a predetermined starting time, the starting operation is performed to determine the amplitude of the output voltage from the inverter to the induction coil. The protection operation is started to make it smaller than the inside. Immediately after the start of the start operation, the amplitude of the output voltage from the inverter section to the induction coil is gradually increased to oscillate the start preparation time and start time respectively. The time is measured based on the clock signal of the unit.

  According to the present invention, the start preparation time and the start time are respectively measured based on the clock signal of the oscillating unit, so that when the frequency of the clock signal of the oscillating unit varies, the start preparation time is the same as the start time. Since it changes, the start preparation time can be set to an appropriate length with respect to the start time. In addition, the feedback control of the inverter unit, for example, compared to the case where the frequency of the operation of the switching unit in the inverter unit for each of the start preparation operation and the start operation is determined in advance, variation in characteristics of circuit components and surroundings The amplitude of the output voltage of the inverter unit can be stabilized regardless of the temperature.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the control section gradually increases the amplitude of the output voltage from the inverter section to the induction coil even immediately after the start of the start preparation operation.

  According to the present invention, compared with a case where the amplitude of the output voltage from the inverter unit to the induction coil is rapidly increased stepwise immediately after the start preparation operation is started, the electrical stress applied to the circuit components is reduced.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the control unit reduces the amplitude of the output voltage from the inverter unit to the induction coil as the ambient temperature increases.

  According to the present invention, when the ambient temperature is high and the voltage required for lighting the electrodeless discharge lamp is low, the amplitude of the output voltage from the inverter unit to the induction coil is reduced, so that the electric power applied to the circuit component is reduced. Stress is reduced.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the oscillation unit increases the frequency of the clock signal as the ambient temperature increases.

  According to this invention, when the ambient temperature is high and the start preparation time and start time necessary for lighting the electrodeless discharge lamp are short, the start preparation time and the start time are shortened by increasing the frequency of the clock signal. Therefore, electrical stress applied to circuit components is reduced.

  The invention of claim 5 is the invention according to any one of claims 1 to 4, wherein the control unit before the protection operation is first performed after the power is turned on, than after the protection operation is performed. The start preparation time and the start time are shortened, respectively.

  According to the present invention, in an environment where the electrodeless discharge lamp is easily lit and the protective operation is not started, the start preparation time is made relatively short, so that Such electrical stress is reduced and the time required for lighting the electrodeless discharge lamp is shortened. If the environment is such that the electrodeless discharge lamp is difficult to turn on, the startability is improved by increasing the start preparation time and the start time after the protection operation.

  The invention of claim 6 includes the electrodeless discharge lamp lighting device according to any one of claims 1 to 5 and a fixture main body for holding the electrodeless discharge lamp lighting device.

  According to the first aspect of the present invention, the start preparation time and the start time are timed based on the clock signal of the oscillating unit, respectively, so that when the frequency of the clock signal of the oscillating unit varies, the start preparation time also becomes the start time. Therefore, the start preparation time can be set to an appropriate length with respect to the start time. In addition, the feedback control of the inverter unit, for example, compared to the case where the frequency of the operation of the switching unit in the inverter unit for each of the start preparation operation and the start operation is determined in advance, variation in characteristics of circuit components and surroundings The amplitude of the output voltage of the inverter unit can be stabilized regardless of the temperature.

  According to the second aspect of the present invention, the control unit gradually increases the amplitude of the output voltage from the inverter unit to the induction coil immediately after the start of the start preparation operation. Compared with the case where the amplitude of the output voltage to the coil is abruptly increased stepwise, the electrical stress applied to the circuit components is reduced.

  According to the invention of claim 3, when the ambient temperature is high and the voltage required for lighting the electrodeless discharge lamp is low, the amplitude of the output voltage from the inverter unit to the induction coil is reduced, so that the circuit component The electrical stress applied to is reduced.

  According to the invention of claim 4, when the ambient temperature is high and the start preparation time and start time necessary for lighting the electrodeless discharge lamp are short, the start preparation time and the start time are increased by increasing the frequency of the clock signal. Therefore, the electrical stress applied to the circuit components is reduced.

  According to the invention of claim 5, the control unit shortens the start preparation time and the start time before the protection operation is performed for the first time after the power is turned on, than after the protection operation is performed. Therefore, in an environment where the electrodeless discharge lamp is easily lit and the protective operation is not started, the start preparation time is made relatively short, so that The stress is reduced and the time required for lighting the electrodeless discharge lamp is shortened. If the environment is such that the electrodeless discharge lamp is difficult to turn on, the startability is improved by increasing the start preparation time and the start time after the protection operation.

In the embodiment of the present invention, when the electrodeless discharge lamp is not lit, time t is taken on the horizontal axis, and an example showing a time change of the clock voltage Vck, the coil voltage Vx, the inverter input voltage Vdc, and the operating frequency f FIG. It is a circuit block diagram which shows the same as the above. It is a perspective view which shows an example of the usage pattern same as the above. It is explanatory drawing which shows an example of the structure of an electrodeless discharge lamp. It is explanatory drawing which shows the relationship between the operating frequency f in case DC voltage is a target voltage, and voltage amplitude | Vx |. In the same as above, when the electrodeless discharge lamp is lit, it is an explanatory diagram showing an example of a time change of the coil voltage Vx with time t on the horizontal axis. It is the partially broken front view which shows an example of the lighting fixture using the same. It is a front view which shows another example of the lighting fixture using the same as the above. (A)-(c) shows another example of the lighting fixture using each same as the above, (a) is a front view, (b) is a bottom view, (c) is a left view.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In the present embodiment, as shown in FIG. 1, an induction coil 5 that is disposed in proximity to the electrodeless discharge lamp 6 and forms a load circuit together with the electrodeless discharge lamp 6, and AC power supplied from an AC power source AC is converted into DC power. A DC power supply unit 1 for converting to DC, a DC power output from the DC power supply unit 1 into a high-frequency AC power having a frequency of 50 kHz to 200 kHz, for example, and output to the induction coil 5, and an inverter unit 2 2 is a voltage that is output to the induction coil 5 (hereinafter referred to as “coil voltage”) Vx amplitude (hereinafter referred to as “voltage amplitude”) | Vx | As shown in FIG. 2, the voltage detection unit 4 that outputs Vxs and the output voltage (hereinafter referred to as “inverter input voltage”) Vdc of the DC power supply unit 1 are maintained at a constant target voltage Vs. With the feedback control of the flow source unit 1, and a control unit 3 for controlling the inverter section 2 based on the detection voltage Vxs of the voltage detection unit 4 outputs.

  The induction coil 5 is wound around a cylindrical coupler 50 as shown in FIG. In the example of FIG. 3, the electrodeless discharge lamp lighting device of the present embodiment is housed in a metal case 10 and is electrically connected to the induction coil 5 through a feeder 10 a.

  As shown in FIG. 4, the electrodeless discharge lamp 6 includes a hollow bulb 61 made of a transparent material such as glass and having a recess 60 on the outer surface, and a cylindrical shape made of synthetic resin. And a base 62 attached so as to surround the opening of 60. The coupler 50 is inserted into the recess 60 and is disposed in the vicinity of the induction coil 5. For example, a discharge gas containing an inert gas and metal vapor is sealed in the bulb 61. Further, a convex portion 60 a to be inserted into the coupler 50 protrudes from the bottom surface of the concave portion 60 of the valve 61. Further, a protective film 61a and a phosphor film 61b are provided on the inner surface of the bulb 61. That is, when arc discharge is generated in the bulb 61 by the high-frequency electromagnetic field generated by the induction coil 5, the generated ultraviolet light is converted into visible light in the phosphor film 61b, so that the electrodeless discharge lamp 6 emits light.

  The DC power supply unit 1 includes a diode bridge DB that full-wave rectifies an AC current supplied from the AC power supply AC, and a series circuit of an inductor L0, a diode D0, and an output capacitor C0 connected between the output terminals of the diode bridge DB. A well-known booster comprising a switching element Q0 connected between a connection point of the inductor L0 and the diode D0 and an output terminal on the low voltage side of the diode bridge DB, and a drive circuit 11 for driving the switching element Q0 on and off. Type converter (boost converter). Since the drive circuit 11 as described above can be realized by a well-known technique, detailed illustration and description thereof are omitted. The control unit 3 detects the inverter input voltage Vdc when a voltage obtained by dividing the voltage across the output capacitor C0 (that is, the inverter input voltage) Vdc is input, and also detects the detected inverter input voltage Vdc at a constant target. A central control circuit 30 is provided that performs feedback control of the drive circuit 11 so as to drive the switching element Q0 on and off with a duty ratio such as the voltage Vs. Such a central control circuit 30 can be realized by using an integrated circuit including an error amplifier, for example.

  The inverter unit 2 has one end at the connection point between the switching elements Q1, Q2 and the series circuit of the switching elements Q1, Q2 and the detection resistor Rd connected between the output ends of the DC power supply unit 1, that is, between both ends of the output capacitor C0. The connected inductor Ls, a series capacitor Cs having one end connected to the other end of the inductor Ls and the other end connected to one end of the induction coil 5, and one end connected to a connection point between the inductor Ls and the series capacitor Cs. A parallel capacitor Cp whose other end is connected to a connection point between the detection resistor Rd and the induction coil 5 and a drive circuit 21 that alternately turns on and off the switching elements Q1 and Q2 are provided. That is, the switching elements Q1 and Q2 constituting the switching unit in the claims are alternately turned on and off, so that the inductor Ls, the series capacitor Cs, and the parallel capacitor Cp constituting the resonance unit in the claims are configured together with the induction coil 5. The connection between the resonance circuit and the DC power supply unit 1 is switched, and the resonance of the resonance circuit converts the DC power output from the DC power supply unit 1 into high-frequency AC power and supplies it to the induction coil 5. The switching elements Q1 and Q2 are each composed of an N-channel FET, and the drive circuit 21 outputs a rectangular wave drive signal to the gates of the switching elements Q1 and Q2, respectively. Q2 is driven on and off, respectively. Furthermore, the drive circuit 21 has a control terminal CON, and the higher the control current Io flowing out from the control terminal CON, the higher the frequency (hereinafter referred to as “operation frequency”) f at which the switching elements Q1 and Q2 are turned on / off. To do. Usually, like the frequencies f1 to f4 shown in FIG. 5, the operating frequency f is in a range higher than the resonance frequency (hereinafter simply referred to as “resonance frequency”) f0 of the resonance circuit described above, and the control current f As Io decreases and the operating frequency f decreases, the voltage amplitude | Vx | increases and the power supplied from the inverter unit 2 to the induction coil 5 increases. In FIG. 5, the upper curve A shows the relationship between the voltage amplitude | Vx | and the operating frequency f when the inverter input voltage Vdc is the target voltage Vs and the electrodeless discharge lamp 6 is turned off. The lower curve B shows the relationship between the voltage amplitude | Vx | and the operating frequency f when the inverter input voltage Vdc is the target voltage Vs and the electrodeless discharge lamp 6 is lit.

  The voltage detection unit 4 includes a rectifying diode, a voltage dividing resistor, and a smoothing capacitor, and outputs a detection voltage Vxs that is a DC voltage having a higher voltage value as the voltage amplitude | Vx | is larger.

  The control unit 3 also includes a sweep circuit 31 that performs a sweep operation that gradually increases the output power from the inverter unit 2 to the induction coil 5 by gradually decreasing the operating frequency f when the electrodeless discharge lamp 6 is started. .

  The sweep circuit 31 includes an operational amplifier OP1 having an inverting input terminal connected to the output terminal via the feedback resistor R3 and connected to the output terminal of the voltage detection unit 4 via the input resistor R4. The output terminal of the operational amplifier OP1 is connected to the control terminal CON of the drive circuit 21 through a series circuit of a backflow prevention diode D1 and an output resistor R5. The sweep circuit 31 includes a resistor R1 having a constant voltage Vd input at one end, a series circuit of a switch SW and a resistor R10 having one end connected to the other end of the resistor R1 and the other end connected to the circuit ground. A parallel circuit of a resistor R2 and a capacitor C1 is provided, and a non-inverting input terminal of the operational amplifier OP1 is connected to a connection point between the parallel circuit and the resistor R1. In the sweep circuit 31 of the present embodiment, since the inverting input terminal of the operational amplifier OP1 is connected to the output terminal of the voltage detector 4 via the input resistor R4 as described above, the larger the amplitude | Vx | That is, as the power supplied from the inverter unit 2 to the induction coil 5 increases, the output voltage of the operational amplifier OP1 decreases, and the current flowing from the control terminal CON of the drive circuit 21 into the sweep circuit 31 (hereinafter referred to as “sweep current”). The power supplied from the inverter unit 2 to the induction coil 5 is reduced by increasing Isw and increasing the operating frequency f. That is, the sweep circuit 31 also performs a feedback operation using the detection voltage Vxs output from the voltage detection unit 4. Further, in the sweep circuit 31, when considering the operation in a state where the voltage Vc1 across the capacitor C1 is stable, when the switch SW is turned on, both ends of the capacitor C1 are compared with when the switch SW is turned off. The voltage amplitude | Vx | decreases as the voltage Vc1 decreases, the output voltage of the operational amplifier OP1 decreases, the sweep current Isw increases, and the operating frequency f increases. When the switch SW is switched from on to off, the output voltage of the operational amplifier OP1 gradually increases and the sweep current Isw gradually decreases due to the time constant of the circuit formed by the resistors R1 and R2 and the capacitor C1. Thus, a sweep operation is performed in which the operating frequency f is gradually lowered and the voltage amplitude | Vx | is gradually increased.

  The control unit 3 includes a feedback circuit 32 that controls the operating frequency f based on the voltage at the connection point between the low-side switching element Q2 and the detection resistor Rd in the inverter unit 2, that is, the current flowing through the inverter unit 2. The feedback circuit 32 includes an operational amplifier OP2 in which a predetermined reference voltage Vr1 is input to a non-inverting input terminal and an output terminal is connected to the control terminal CON of the drive circuit 21 via a diode D2 and an input resistor R6. The inverting input terminal of the operational amplifier OP2 is connected to the output terminal of the operational amplifier OP2 through a parallel circuit of the resistor R7 and the capacitor C2, and is connected to a connection point between the switching element Q2 and the detection resistor Rd through the resistor R8. ing. That is, the current (hereinafter referred to as “feedback current”) Ifb flowing from the control terminal CON of the drive circuit 21 into the feedback circuit 32 increases as the current flowing through the induction coil 5 increases (that is, the power supplied to the induction coil 5). The higher the frequency, the more the power supplied to the induction coil 5 decreases, and the feedback circuit 32 operates so that the power supplied from the inverter unit 2 to the induction coil 5 is kept constant. The sweep circuit 31 and the feedback circuit 32 each have an operating frequency f in a state where the inverter input voltage Vdc is the target voltage Vs and the switch SW is turned off in the sweep circuit 31 and the voltage across the capacitor C1 is stable. A lighting frequency f1 (see FIG. 5) such that electric power to the extent that H discharge (arc discharge also called high frequency electromagnetic field discharge or inductively coupled discharge) is generated in the electrodeless discharge lamp 6 is supplied from the inverter unit 2 to the induction coil 5. And the inverter input voltage Vdc is the target voltage Vs and the switch SW is turned on in the sweep circuit 31 and the voltage across the capacitor C1 is stable, the operating frequency f is E in the electrodeless discharge lamp 6. Electricity that can cause discharge (glow discharge, also called high-frequency electric field discharge or capacitively coupled discharge) There has been designed to be turned off frequency f3 as supplied to the induction coil 5 from the inverter section 2. When the inverter input voltage Vdc is lower than the target voltage Vs by the feedback of the sweep circuit 31 and the feedback circuit 32, the operating frequency f is lowered than the above, and conversely, the inverter input voltage Vdc is higher than the target voltage Vs. The operating frequency f is set higher than the above. That is, the voltage amplitude | Vx | as a result of the feedback control is such that arc discharge (H discharge) occurs in the electrodeless discharge lamp 6 when the switch SW is turned off in the sweep circuit 31 and the voltage across the capacitor C1 is stable. In a state where the switch SW is turned on in the sweep circuit 31 and the voltage across the capacitor C1 is stable, no arc discharge (H discharge) occurs in the electrodeless discharge lamp 6 and glow discharge (E discharge) occurs. Is considered to occur. The effective value of the output voltage Vx of the inverter unit 2 is set to, for example, 400V to 700V as the maximum value during the start preparation operation P1, and is set to, for example, 1000V to 2500V as the maximum value during the start operation P2.

  When the power is turned on, the central control circuit 30 first maintains the switch SW of the sweep circuit 31 in the ON state as shown in FIG. 1 so that the arc amplitude does not occur in the electrodeless discharge lamp 6. The start preparation operation P1 for keeping Vx | small is performed only for a predetermined start preparation time, and then the switch SW of the sweep circuit 31 is turned off, so that the voltage amplitude | Vx to the extent that arc discharge occurs in the electrodeless discharge lamp 6 The operation proceeds to the starting operation P2 for increasing |. At the start of the start preparation operation P1 and at the start of the start operation P2, the sweep operation that gradually increases the voltage amplitude | Vx | by gradually increasing the voltage across the capacitor C1 of the sweep circuit 31. Is made. Furthermore, in this embodiment, a time constant circuit 33 including a series circuit of a parallel circuit of a capacitor C4 and a resistor R11 and a resistor R12 is connected between the control terminal CON of the drive circuit 21 of the inverter unit 2 and the ground. The above sweep operation is also achieved by the time constant of the time constant circuit 33 at the start of the start preparation operation P1. Since the above sweep operation is based on the time constant of the circuit such as the time constant circuit 33, the duration of the sweep operation varies depending on the temperature characteristics of the circuit components such as the capacitors C1 and C4 and changes over time. It does not depend on a clock signal output from an oscillating unit 91 described later.

  During the starting operation P2, arc discharge is generated in the electrodeless discharge lamp 6 so that the electrodeless discharge lamp 6 is turned on, and the output power to the induction coil 5 is maintained substantially constant as shown in FIG. Transition to the steady operation P3.

  In the present embodiment, the operation frequency f is feedback controlled based on the value of the current flowing through the detection resistor Rd and the detection voltage Vxs, and therefore, for example, the operation frequency f is predetermined for each of the start preparation operation P1 and the start operation P2. The voltage amplitude | Vx | can be stabilized regardless of variations in circuit component characteristics and ambient temperature, and the voltage amplitude | Vx | becomes excessively large, which causes excessive electrical stress on the circuit components. It can be avoided that the voltage amplitude | Vx | becomes too small and the electrodeless discharge lamp 6 does not light. .

  Further, during the start operation, the control unit 3 determines whether or not the electrodeless discharge lamp 6 is lit based on, for example, the detection voltage Vxs output by the voltage detection unit 4 and the start operation is started (that is, After the switch SW of the sweep circuit 31 is turned off), when a predetermined starting time has passed without determining whether the electrodeless discharge lamp 6 is turned on, a protection operation P4 for reducing the voltage amplitude | Vx | is started. Specifically, the protection operation P4 is, for example, stopping the output of power from the inverter circuit 2 to the induction coil 5 by turning off the switching elements Q1 and Q2 of the inverter circuit 2, respectively. Further, in the present embodiment, the central control circuit 30 counts the number of times of protection, which is the number of times that the protection operation P4 is continuously performed, and the protection operation P4 is predetermined until the number of protection times reaches a predetermined upper limit number. After the protection time continues, the start preparation operation P1 is started again. After the protection count reaches the upper limit, the protection operation P4 is continued without performing the start preparation operation P1 again even after the above protection time has elapsed. To do. The protection operation P4 is not limited to the above, and for example, the voltage amplitude | Vx | may be smaller than the start preparation operation P1. In the example of FIG. 1, immediately before the protection operation P4 is started, the operation frequency f is a frequency in the steady operation P3 by feedback control for keeping the voltage amplitude | Vx | constant with respect to the decrease of the inverter input voltage Vdc. The frequency f4 is lower than f1. Further, during the protection operation P4, the central control circuit 30 stops the drive circuit 11 of the DC power supply unit 1, so that the inverter input voltage Vdc is maintained until the protection operation P4 ends and the start preparation operation P1 starts. Is constant without returning to the target voltage Vs.

  Here, the present embodiment includes an oscillating unit 91 that outputs a clock signal whose voltage value (hereinafter referred to as “clock voltage”) Vck periodically changes. The central control circuit 30 includes the oscillating unit 91. Using the output clock signal, the start preparation time and the start time are measured. In the example of FIG. 1, the waveform of the clock voltage Vck is a triangular wave, the start preparation time and the start time are each two cycles of the clock signal, and the start preparation operation P1 is started and the start operation P2 is started. Each of the timings is the peak time of the clock voltage Vck. Thereby, in this embodiment, when the frequency of the clock signal of the oscillation unit fluctuates before the start preparation operation P1 or after the start operation P2, the start preparation time and the start time are interlocked so as to maintain a constant ratio. Since it changes, the start preparation time can be set to an appropriate length with respect to the start time. Accordingly, the time required for lighting the electrodeless discharge lamp 6 is shortened by shortening the start preparation time compared to the case where the start preparation time is made constant assuming that the start time is the longest.

  Furthermore, the present embodiment includes a temperature detection unit 92 that detects the ambient temperature, and the oscillation unit 91 increases the frequency of the clock signal output to the central control circuit 30 as the ambient temperature detected by the temperature detection unit 92 increases. Increase to shorten start preparation time and start time respectively. For example, the temperature detection unit 92 is configured such that a constant voltage is input to one end of a series circuit of a thermistor and a resistor, and a connection point between the thermistor and the resistor is an output end. In other words, the higher the temperature, the easier the arc discharge occurs in the electrodeless discharge lamp 6, the necessary start-up preparation time and start-up time are shortened, and the deterioration of circuit components due to electrical stress generally occurs at higher temperatures. In accordance with the fact that it is easy to perform, the start preparation time and the start time are shortened to suppress the electrical stress applied to the circuit components. In this embodiment, the start preparation time and the start time are substantially the same length, and the start preparation time and the start time are 50 ms to 100 ms, for example. These values are the values of the electrodeless discharge lamp 6 and the circuit components. What is necessary is just to set suitably according to a characteristic. Further, the above operation of the oscillating unit 91 can be realized by using, for example, a capacitor such as a B characteristic or F characteristic whose characteristics change relatively depending on the temperature, instead of the temperature detecting unit 92 and the thermistor as described above. You can also

  Further, the central control circuit 30 compares the inverter input voltage Vdc with a predetermined lower limit voltage as needed, and when the non-lighting of the electrodeless discharge lamp 6 is detected when the inverter input voltage Vdc falls below the lower limit voltage. The monitoring operation of performing the protection operation P4 is also performed. The lower limit voltage is, for example, 80% of the target voltage Vs. If this configuration is employed, the circuit component can be protected from electrical stress by the protection operation P4 when an abnormality occurs such that the inverter input voltage Vdc decreases. However, since the inverter input voltage Vdc tends to temporarily decrease during the start operation P2 and immediately after the start operation P2, the protection operation P4 is erroneously started due to the temporary decrease in the inverter input voltage Vdc. In order to avoid this, the central control circuit 30 starts the above monitoring operation only when lighting of the electrodeless discharge lamp 6 is detected after a predetermined grace period after the start operation P2 has started. The monitoring operation is not performed before that. It is desirable that the above-mentioned grace period is longer than the starting time so that the monitoring operation is not started until the inverter input voltage Vdc is stabilized to some extent after the electrodeless discharge lamp 6 is turned on (after transition to the steady operation P3). For example, when the starting time is set to two cycles of the clock signal as described above, the grace time is set to three cycles of the clock signal.

  In the example of FIG. 1, the protection time is also equivalent to two cycles of the clock signal. However, it is not preferable that the protection time is shortened even when the ambient temperature is high. Thus, it is desirable that the time is separately measured by a time measuring means having very small temperature dependency.

  Also, instead of changing the start preparation time, start time, or grace time by changing the frequency of the clock signal as described above, the start is made by changing the number of clock signal cycles that are set as the start preparation time, start time, or grace time. Preparation time, start-up time and grace time may be changed. For example, when the temperature detected by the temperature detection unit 92 is equal to or higher than a predetermined threshold (for example, 40 ° C.), the start preparation time and the start time are each set as one cycle of the clock signal, and the temperature is the threshold value. When the ambient temperature is higher, the number of cycles of the clock signal used as the start preparation time, the start time, and the grace time is set such that the start preparation time and the start time are each two cycles of the clock signal. Reduce each.

  By the way, as the temperature is higher, arc discharge is more likely to occur in the electrodeless discharge lamp 6, and the voltage amplitude | Vx | required during the start preparation operation P1 and the start operation P2 tends to decrease. Therefore, the electrical stress applied to the circuit components may be reduced by decreasing the voltage amplitude | Vx | during the start preparation operation P1 or the start operation P2 as the temperature increases. Specifically, for example, a temperature-sensitive resistor whose resistance value decreases as the temperature increases is used for the resistor R10 of the sweep circuit 31 and the resistor R12 of the time constant circuit 33, respectively. In this case, the time required for the sweep operation also varies depending on the ambient temperature. However, when the above-mentioned temperature sensitive resistor is used as the resistor R10 of the sweep circuit 31, the start preparation operation P1 is changed to the resistor R12 of the time constant circuit 33. When the temperature sensitive resistor is used, the voltage amplitude | Vx | can be reduced as the temperature increases in the start preparation operation P1, the start operation P2, and the steady operation P3.

  Further, before the protection operation P4 is performed for the first time after the power is turned on, the central control circuit 30 may make the start preparation time and the start time shorter than those after the protection operation P4 is performed. Good. For example, in the initial start preparation operation P1 and the start operation P2 after the power is turned on, the start preparation time and the start time are set to one cycle of the clock signal, respectively, and the start preparation operation P1 after the protection operation P4 is performed. In the start operation P2, the start preparation time and the start time are set to two cycles of the clock signal, respectively. If this configuration is adopted, the start preparation time and the start time are relatively shortened in the environment where the electrodeless discharge lamp 6 is easily lit and the protective operation P4 is not started. As a result, the electrical stress applied to the circuit components can be reduced and the time required for lighting the electrodeless discharge lamp 6 can be shortened. Further, for example, when the ambient temperature is as low as 0 ° C. to −40 ° C. or in an environment where the electrodeless discharge lamp 6 is difficult to turn on, such as in a dark place, the start preparation time is set after the first protection operation P4. The startability is improved by increasing the start time.

  For example, as shown in FIGS. 7 and 8, the above various electrodeless discharge lamp lighting devices can be held together with an electrodeless discharge lamp 6 and a coupler 50 in an appropriately shaped fixture body 71 to constitute a lighting fixture 7. . Since such a fixture main body 71 and the lighting fixture 7 can be realized by a well-known technique, detailed illustration and description thereof will be omitted.

  Also, in general, the electrodeless discharge lamp 6 has a longer life and is less likely to fail than a discharge lamp having an electrode inside, so that it is used in places where maintenance work is difficult such as in tunnels. It is suitable as a light source. Therefore, the above electrodeless discharge lamp lighting device may be used for the lighting device 7 for tunnel illumination having a structure as shown in FIGS. Hereinafter, the lighting fixture 7 of FIGS. 9A to 9C will be described in detail with reference to FIG. 9A as the reference for the vertical and horizontal directions, and the vertical direction of FIG.

  9 (a) to 9 (c), the fixture main body 71 is made of, for example, a rectangular parallelepiped body 71a made of stainless steel and a transparent material such as tempered glass. A cover 71b for closing and opening the 71a. Further, a U-shaped reflecting plate 71c made of, for example, aluminum and distributing light of the electrodeless discharge lamp 6 forward is fixed to the inner bottom surface of the body 71a, and the electrodeless electrode housed in the instrument body 71 is fixed. The light from the discharge lamp 6 is emitted forward through the cover 71b. Furthermore, the inner bottom surface of the body 71a is electrically connected to the coupler 50 to which the electrodeless discharge lamp 6 is attached, the case 10 housing the electrodeless discharge lamp lighting device, and the DC power supply unit 1 in the case 10. Terminal blocks 8 are fixed to each other. The terminal block 8 is connected to the other end of an electric wire (not shown) whose one end is connected to the AC power source AC. The DC power source 1 is connected to the AC power source via the electric wire and the terminal block 8. Electrically connected to AC. In addition, an electric wire insertion hole 71d for inserting an electric wire connected to the terminal block 8 is vertically provided in the lower wall of the body 71a. Further, the cover 71b is connected to the upper end portion of the body 71a via the hinge 71e at the upper end portion thereof, so that the cover 71b is closed at the closed position and the closed position as shown in FIGS. It can rotate with respect to the body 71a in the plane seen from the left-right direction between the open position where the lower end of the body is directed forward and the body 71a is released. A latch 71f that locks the lower end of the cover 71b in the closed position is provided at the lower end of the body 71a. Since the hinge 71e and the latch 71f as described above can be realized by a well-known technique, detailed illustration and description are omitted. Furthermore, on the rear surface of the body 71a, two mounting legs 71g made of, for example, a steel plate and fixed to the mounting surface (not shown) such as a wall surface are fixed side by side. Yes. The upper and lower end portions of each mounting foot 71g protrude vertically from the body 71a as viewed from the front, and screw insertion holes 71h are provided through the protruding portions in the front-rear direction. The instrument body 71 is screwed and fixed to the mounting surface by a screw (not shown) that is inserted into the screw insertion hole 71h and screwed into the mounting surface.

DESCRIPTION OF SYMBOLS 1 DC power supply part 2 Inverter part 3 Control part 5 Inductive coil 6 Electrodeless discharge lamp 7 Lighting fixture 71 Appliance main body 91 Oscillation part

Claims (6)

An induction coil disposed close to the electrodeless discharge lamp;
A DC power supply unit that consists of a switching power supply and outputs DC power;
A resonance unit that forms a resonance circuit together with the induction coil, and a switching unit that periodically switches the connection between the DC power supply unit and the resonance unit, and converts the DC power output from the DC power supply unit to AC power and supplies it to the induction coil An inverter unit to
An oscillator that generates a periodic clock signal;
A feedback control of the DC power supply unit so that the output voltage of the DC power supply unit is a predetermined target voltage, and a control unit that feedback-controls the frequency of operation of the switching unit in the inverter unit,
The control unit performs a start preparation operation for setting the amplitude of the output voltage from the inverter unit to the induction coil so that the amplitude of the electrodeless discharge lamp is small and not zero over a predetermined start preparation time. In order to start lighting the lamp, a starting operation is performed to relatively increase the amplitude of the output voltage from the inverter unit to the induction coil, and it is determined whether the electrodeless discharge lamp is lit during the starting operation. When the lighting operation of the electrodeless discharge lamp is not determined even if the starting operation continues for a predetermined starting time, a protective operation is started to make the amplitude of the output voltage from the inverter unit to the induction coil smaller than during the starting operation. Immediately after starting the starting operation, the amplitude of the output voltage from the inverter unit to the induction coil is gradually increased, and the start preparation time and the start time are respectively set to the clock of the oscillation unit. An electrodeless discharge lamp lighting apparatus characterized by counting based on the signal.   2. The electrodeless discharge lamp lighting device according to claim 1, wherein the control unit gradually increases the amplitude of the output voltage from the inverter unit to the induction coil immediately after the start preparation operation is started.   3. The electrodeless discharge lamp lighting device according to claim 1, wherein the control unit reduces the amplitude of the output voltage from the inverter unit to the induction coil as the ambient temperature is higher.   4. The electrodeless discharge lamp lighting device according to claim 1, wherein the oscillation unit increases the frequency of the clock signal as the ambient temperature increases. 5.   The control unit shortens the start preparation time and the start time, respectively, after the protection operation is performed before the protection operation is performed for the first time after the power is turned on. The electrodeless discharge lamp lighting device of any one of -4.   A lighting fixture comprising: the electrodeless discharge lamp lighting device according to any one of claims 1 to 5; and a fixture main body that holds the electrodeless discharge lamp lighting device.

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