JP2005135619A - Electrode-less discharge lamp lighting device and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost and simple electrode-less discharge lamp lighting device surely controlling an output power with a simple structure with little stress on components. <P>SOLUTION: A power conversion circuit 4 is connected to an induction coil 2 wound around in the vicinity of the electrode-less discharge lamp 1 through a resonance circuit 3, and a control circuit 7 changing drive frequencies of a switching element Q2 of the power conversion circuit 4, a current detection circuit 8 detecting a current value of a main electrode of the switching element Q2, and a phase detection circuit 9 for detecting phases of the resonance circuit 3 or the power conversion circuit 4 or a current or a voltage of the induction coil 2, are provided. The control circuit 7 is to control the drive frequencies of the switching element Q2 in accordance with a given reference value, detection output of phase detection circuit 9, and the detection output of the current detection circuit 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrodeless discharge lamp lighting device that emits light by applying a high-frequency electromagnetic field to an electrodeless discharge lamp made of a translucent material in which a discharge gas is enclosed, and an illumination device using the same.

  FIG. 12 is a circuit diagram of a conventional general discharge lamp lighting device. Here, a hot cathode discharge lamp (for example, a fluorescent lamp) having a pair of filament electrodes is used as the discharge lamp La. A series circuit of switching elements Q1 and Q2 as a high frequency inverter circuit is connected to the DC power supply circuit. Switching elements Q1 and Q2 are alternately turned on and off at a high frequency by a drive circuit. A parallel circuit of the discharge lamp La and the resonance capacitor C2 is connected to both ends of the switching element Q2 via a DC cut capacitor C1 and a resonance inductor L1. The capacity of the DC cut capacitor C1 is set sufficiently larger than the capacity of the resonance capacitor C2.

  When the switching element Q1 is on and the switching element Q2 is off, current flows from the DC power supply circuit through the switching element Q1, inductor L1, capacitor C1, discharge lamp La filament, capacitor C2, discharge lamp La filament, and switching. When the element Q1 is off and the switching element Q2 is on, current flows from the capacitor C1 through the inductor L1, the switching element Q2, the filament of the discharge lamp La, the capacitor C2, and the filament of the discharge lamp La.

  By setting the on / off frequency of the switching elements Q1, Q2 in the vicinity of the resonance frequency of the inductor L1 and the capacitor C2, a high voltage is generated at both ends of the capacitor C2, and the discharge lamp La is started. When the discharge lamp La is started, the load resistance component of the discharge lamp La is applied in parallel with the resonance capacitor C2, so that the resonance frequency changes. Therefore, the on / off frequency of the switching elements Q1, Q2 is set to the frequency at the start. Change from to the lighting frequency.

  This conventional example includes a control circuit 7 for keeping the power during lamp operation substantially constant. As shown in FIG. 1, the current flowing through the main electrode of the switching element Q2 is detected by the current detection circuit 8, and the output of the comparison calculation means 17 is set so that the detected value becomes substantially equal to the set value of the indicated value generation circuit 10. Thus, the oscillation frequency of the drive circuit 6 is changed, and the on / off frequencies of the switching elements Q1, Q2 are changed.

  FIG. 13 shows the frequency characteristics of the resonance circuit. The horizontal axis is the on / off operating frequency of the switching elements Q1 and Q2, and the vertical axis is the voltage of the resonance capacitor C1. Before the lamp is lit, it is operated at the operating point a having no load characteristics. When the discharge lamp La is lit, the resistance component of the discharge lamp La is added, so that the resonance frequency of the resonance circuit changes greatly. The operating frequencies of the switching elements Q1 and Q2 are changed so as to operate at. At the operating point b, the operating frequency for obtaining a desired load output can be uniquely determined. That is, in the circuit as shown in FIG. 1, if the current flowing through the main electrode of the switching element Q2 is detected, the power output to the load at that time can be estimated, and the output power can be controlled. .

  In the conventional example of FIG. 12, the average value of the positive section of the current value flowing through the main electrode of the switching element Q2 is detected, but the effective value, peak value, average value of the negative section, average value of the absolute value, etc. May be detected.

Patent Documents 1 and 2 propose an electrodeless discharge lamp lighting device that detects the phase difference between the output voltage and output current of the inverter and controls the oscillation frequency in accordance with the phase difference. Reference numeral 1 denotes a technique for improving startability and is irrelevant to the operation at the time of lighting. Further, since Patent Document 2 does not utilize detection of the current value flowing through the main electrode of the switching element, there is a drawback that the configuration becomes complicated.
JP-A-7-65978 Japanese Patent Laid-Open No. 2002-184592

  Consider the case where the above control circuit is applied to an electrodeless discharge lamp lighting device. Here, the electrodeless discharge lamp lighting device is, as shown in FIG. 14, in which an induction coil 2 is wound in the vicinity of an electrodeless discharge lamp 1 in which a discharge gas is sealed, and a high frequency voltage is applied to the induction coil 2. In this lighting device, the electrodeless discharge lamp 1 is caused to emit light by applying a high-frequency electromagnetic field to the electrodeless discharge lamp 1.

  In the electrodeless discharge lamp lighting device shown in FIG. 14, the frequency characteristics of the load voltage are as shown in FIG. In order to start the electrodeless discharge lamp 1, the electrodeless discharge lamp lighting device needs to have a frequency close to the resonance point as an operating point. Further, the inductance component of the induction coil 2 remains large even after the electrodeless discharge lamp 1 is started, and the resonance frequency of the load does not change greatly. In the electrodeless discharge lamp lighting device, a capacitive component connected in series and in parallel to the induction coil 2 is required, and there are two or more resonance points. Therefore, when the average value of the positive value of the current value flowing through the main electrode of the switching element Q2, the effective value or the peak value, the average value of the negative value, the average value of the absolute value, or the like is detected, Even when the detection value is output, the state of the load phase may be different.

  As an example of this, FIG. 16 shows two states in which the average value of the positive section of the current value flowing through the main electrode of the switching element Q2 is the same. In such a case, even if the detected current value is the same, there are several cases where the output power has a different value because the phase of the load is different.

  As described above, the output power cannot be controlled by the current detecting means as in the conventional example described above. Therefore, it becomes impossible to make the light output uniform during the operation of the electrodeless discharge lamp, and it is necessary to use large and expensive parts that can withstand the stress given when excessive power is output. .

  The present invention has been made in order to solve such problems. The object of the present invention is to control output power reliably with a simple configuration, to reduce stress on components, and to be inexpensive and simple. The object is to provide an electrodeless discharge lamp lighting device.

  According to the present invention, in order to solve the above problems, as shown in FIG. 1, an induction coil 2 wound in the vicinity of an electrodeless discharge lamp 1, and an inductance element L1 connected to the induction coil 2 and A resonance circuit 3 including a capacitance element C1, a power conversion circuit 4 including a switching element Q2 and connected to the resonance circuit 3, a power supply circuit 5 for supplying power to the power conversion circuit 4, and the switching element Q2 are driven. An electrodeless discharge lamp comprising: a driving circuit 6 for controlling the switching element Q2 by the driving circuit 6; and a current detection circuit 8 for detecting the current value of the main electrode of the switching element Q2. In the lighting device, a phase detection circuit 9 for detecting the phase of the current or voltage of the resonance circuit 3 or the power conversion circuit 4 or the induction coil 2 is provided. The control circuit 7 controls the drive frequency of the switching element Q2 according to a predetermined instruction value, a detection output of the phase detection circuit 9, and a detection output of the current detection circuit 8. .

According to the first aspect of the present invention, the state of the load can be accurately grasped by the phase detection circuit, and the output power can be controlled reliably, so that the stress on the parts is small, and the electrodeless discharge lamp lighting device is inexpensive and simple. Can be obtained.
According to the second aspect of the present invention, the phase detection can be performed with a relatively simple configuration by using the drive voltage of the switching element or the main electrode terminal voltage as the reference voltage. In particular, when the driving voltage of the switching element is used as a reference voltage, components with low withstand voltage can be used for the phase detection circuit, so that the cost can be reduced.

According to the invention of claim 3, the phase is detected by using the instantaneous value of the current or voltage at the phase detection portion at the time of rising or falling of the reference voltage, using the driving voltage of the switching element or the main electrode terminal voltage as the reference voltage. Since the determination is performed using the instantaneous value, the phase detection does not cause a time delay, and the power can be stabilized by reacting quickly. In addition, when the phase detection circuit is configured as a digital system, an electrodeless discharge lamp lighting device that is inexpensive and highly reliable can be obtained without a complicated configuration.
According to the invention of claim 4, the drive voltage or the main electrode terminal voltage of the switching element is used as a reference voltage, and the sum of the products of instantaneous values for one cycle of the drive frequency of this reference voltage and the current or voltage of the phase detection portion is calculated. Since the phase is detected by using it, stable electric power can be supplied even if a distorted wave is added to the current or voltage of the phase detection portion or a disturbance component such as noise is added.

  FIG. 1 shows an embodiment of an electrodeless discharge lamp lighting device of the present invention. The lighting device includes an electrodeless discharge lamp 1 made of a translucent material in which a discharge gas is sealed, an induction coil 2 wound around the electrodeless discharge lamp 1, and an inductance connected to the induction coil 2. A resonance circuit 3 including an element L1 and a capacitance element C1, a power conversion circuit 4 including switching elements Q1 and Q2, connected to the resonance circuit 3, a power supply circuit 5 for supplying power to the power conversion circuit 4, A driving circuit 6 for driving the switching elements Q1, Q2, a control circuit 7 for changing the driving frequency of the switching elements Q1, Q2 by the driving circuit 6, and a current detection for detecting the current value of the main electrode of the switching element Q2. In the electrodeless discharge lamp lighting device comprising the circuit 8, the current or voltage of the resonance circuit 3, the power conversion circuit 4, or the induction coil 2. A phase detection circuit 9 for detecting a phase is provided, and the switching is performed according to an instruction value of an instruction value generation circuit 10 provided in the control circuit 7, a detection output of the phase detection circuit 9, and a detection output of the current detection circuit 8. The drive frequency of the elements Q1 and Q2 is controlled.

  Here, the phase detection circuit 9 may be one that detects the phase of the peak point of the vibration waveform, one that detects the phase of the zero cross point, or one that detects the phase of the entire waveform. In short, it is sufficient if the difference in load state due to the difference in phase can be understood.

  In order to detect the phase of the current at the phase detection portion, for example, a current transformer is inserted in series into an inductance element or a capacitance element to be detected, and the phase of the current is detected. Alternatively, a current is detected by connecting a minute resistor in series and amplifying the voltage across the resistor with an operational amplifier. In order to detect the phase of the voltage at the phase detection portion, for example, a high-impedance resistance voltage dividing circuit is connected in parallel to the inductance element or capacitance element to be detected, and the phase of the voltage is detected. Alternatively, a secondary winding is provided in the inductance element, and the phase of the voltage is detected by the secondary winding output.

  Thus, by controlling the drive frequency of the switching elements Q1 and Q2 according to the detection output of the phase detection circuit 9, it is possible to accurately grasp the state of the load and control the output power reliably. A low-cost and simple electrodeless discharge lamp lighting device can be obtained with low stress on the components.

  The configuration of the power conversion circuit 4 is not limited to a half-bridge circuit in which two switching elements Q1 and Q2 that are alternately turned on and off are connected in series, but a single combination of one switching element and an LC oscillation circuit. The power converter circuit may be used, or a full bridge circuit is configured by four switching elements, and the DC power supply voltage is converted to a high-frequency AC voltage by alternately turning on and off the diagonal switching elements. Such a configuration may be used.

  Further, as the power supply circuit 5, in the circuit of FIG. 1, the commercial AC power supply Vs is full-wave rectified by the rectifier bridge DB, and direct current is supplied to the smoothing capacitor C3 through the boost chopper circuit 51 including the inductor L3, the switching element Q3, and the diode D3. Although the configuration for obtaining the voltage has been illustrated, the present invention is not limited to this. In the figure, 52 is a control circuit for turning on / off the switching element Q3 at a high frequency.

  A cross-sectional structure of an electrodeless discharge lamp is illustrated in FIG. This electrodeless discharge lamp 1 has a hollow cavity with a concave section opened downward at the center of a substantially spherical bulb 20 made of a translucent material in which a discharge gas containing at least mercury and a rare gas is enclosed. Part 21. The hollow portion 21 houses the induction coil 2 that supplies a high-frequency electromagnetic field to the discharge gas. Further, a magnetic material around which the induction coil 2 is wound is provided with a cylindrical core 22 and a heat dissipating member 23 that is disposed inside the core 22 and is made of a heat conductive material that contacts the core 22. A phosphor 24 is applied to the inside of the bulb 20. The phosphor 24 converts ultraviolet rays generated by vaporized mercury discharge into visible light.

  The electrodeless discharge lamp lighting device of FIG. 1 can be used as a lighting device as shown in FIG. 18, for example. Since the electrodeless discharge lamp 1 is generally driven at a high frequency of several tens of MHz, it is covered with a shield cover 25 such as a metal mesh in order to absorb radiation noise from the lamp. 26 is a base for supporting the induction coil 2, and 27 is a lighting circuit.

  Hereinafter, various embodiments of the present invention will be described. Since the basic configuration in each embodiment is the same as that described in FIG. 1, the portions having substantially the same basic functions are the same. Reference numerals are assigned, and overlapping descriptions of common parts are omitted.

  FIG. 2 shows the configuration of the first embodiment of the present invention. In this embodiment, the phase detection circuit 9 is configured to detect either delay or advance. Thus, since the phase detection circuit 9 is configured to detect either advance or delay, there is an effect that the phase detection circuit 9 is simplified. Further, since the change of the driving frequency based on the detection result of the phase detection circuit 9 may be a binary switching method, for example, a switch element S is provided in the control circuit 7 and the switch is switched according to the detection phase delay / advance determination result. The drive frequency of the drive circuit 6 may be switched by switching ON / OFF of the element S.

  Here, it is assumed that the drive circuit 6 of FIG. 2 includes an oscillation circuit using a capacitor charge / discharge circuit and a voltage comparator, for example. That is, the capacitor is charged with a predetermined charging time constant, and when the voltage of the capacitor reaches the first reference voltage, the output of the voltage comparator is inverted. Thereafter, the capacitor is discharged with a predetermined discharge time constant, and when the voltage of the capacitor reaches a second reference voltage lower than the first reference voltage, the output of the voltage comparator is inverted again. Thereafter, the operation of charging the capacitor with a predetermined time constant is repeated. Thereby, since a rectangular wave voltage is obtained at the output of the voltage comparator, the switching elements Q1, Q2 are alternately turned on and off by this rectangular wave voltage.

  In the control circuit 7, the charge / discharge time constant of the capacitor of the drive circuit 6 or the first or second reference voltage is changed so that the output value of the current detection circuit 8 and the instruction value of the instruction value generation circuit 10 coincide. The frequency of ON / OFF of the switching elements Q1 and Q2 is changed by the switching of the switching element S1 based on the detection result of the phase detection circuit 9. By switching the charge / discharge time constant or the first or second reference voltage, the oscillation frequency of the drive circuit 6 can be switched in two stages according to the phase advance / delay.

  As shown in FIG. 15, the frequency characteristic of the load portion including the resonance circuit in the electrodeless discharge lamp lighting device has several peaks. This peak is caused by a plurality of resonance circuits in the electrodeless discharge lamp lighting device. This is caused by having a resonance point. At each resonance point, the voltage or current of the resonance circuit that contributes to the resonance is reversed in phase delay / advance at the resonance point. Therefore, if the delay or advance of the voltage or current of the resonant circuit that contributes to the resonance is identified at the operating frequency that you want to set as the operating point, the desired operation can be achieved without measuring the phase and phase angle of the entire load characteristics. It is possible to determine whether the point is operating. Thereby, the phase detection circuit and the drive frequency changing means can be simplified, and a more compact and inexpensive electrodeless discharge lamp lighting device can be obtained.

  FIG. 3 shows the configuration of the second embodiment of the present invention. In the present embodiment, the phase detection circuit 9 detects the phase based on the drive voltage Vgs of the switching element Q2. In the circuit of FIG. 3, the switching element Q2 is a MOSFET, and the gate-source drive voltage Vgs is switched between a high level and a low level in accordance with the ON / OFF timing. Therefore, the phase of the voltage or current of the resonance circuit 3 or the induction coil 2 is measured with reference to the drive voltage Vgs of the switching element Q2. For example, the voltage or current of the inductor L1 of the resonance circuit 3, the voltage or current of the capacitor C1, the voltage or current of the capacitor C2, the voltage or current of the induction coil 2 is measured with reference to the drive voltage Vgs of the switching element Q2. .

  In the present embodiment, as described above, the phase detection circuit 9 is configured to detect the phase of the voltage or current of the resonance circuit 3 or the induction coil 2 with reference to the drive voltage Vgs of the switching element Q2. A low voltage can be used, and consideration for partial pressure and withstand voltage can be reduced, and an electrodeless discharge lamp lighting device that is easier to design can be obtained.

  Instead of using the drive voltage Vgs of the switching element Q2 as a reference, the phase may be detected based on the main electrode terminal voltage Vds of the switching element Q2. In this case, a voltage dividing resistor may be connected in parallel between the drain and source of the switching element Q2, and the voltage or current phase of the resonance circuit 3 or the induction coil 2 may be detected based on the voltage at the voltage dividing point. . In this case, since the voltage that can grasp the maximum value can be used as a reference, the phase of the voltage or current of the resonance circuit 3 or the induction coil 2 is detected with respect to the phase of the peak value of the main electrode terminal voltage Vds of the switching element Q2. can do.

  FIG. 4 shows the configuration of the third embodiment of the present invention. In the present embodiment, the phase detection circuit 9 measures the phase using the instantaneous value of the output current of the power conversion circuit 4 when the drive voltage Vgs of the switching element Q2 falls. When the falling detection circuit 11 operates, the instantaneous value of the output current is taken and the phase is determined by the sign of the value. Since the determination is performed using the instantaneous value, no time delay occurs in the phase detection circuit 9, and it is possible to react quickly and stabilize the power. Further, when the phase detection circuit 9 is configured as a digital system, an electrodeless discharge lamp lighting device that is inexpensive and highly reliable can be obtained without a complicated configuration.

  FIG. 5 shows the configuration of Embodiment 4 of the present invention. In the present embodiment, the phase detection circuit 9 uses the drive voltage Vgs or the main electrode terminal voltage Vds of the switching element Q2 as a reference voltage, and an instantaneous value for one cycle of the drive frequency between the reference voltage and the current or voltage of the phase detection portion. The phase is detected using the sum of the products. By performing such detection, even if a distorted wave is added to the current or voltage of the phase detection part or a disturbance component such as noise is added, the phase detection result is not affected, so stable power is supplied. It becomes possible to do.

  According to the configuration illustrated in FIG. 5, the phase detection circuit 9 includes a multiplier 91, an integrator 92, and a phase discriminator 93. A multiplier 91 obtains the product of the reference voltage and the instantaneous value of the current or voltage of the phase detection portion. The integrator 92 integrates the output value of the multiplier 91 for one drive frequency period. The phase discriminator 93 compares the output of the integrator 92 with a predetermined level and outputs a binary signal.

  When the driving voltage Vgs of the switching element Q2 is used as the reference voltage of the phase detection circuit 9, an analog switch circuit may be used as the multiplier 91. Further, as the integrator 92, a low-pass filter circuit such as a CR integration circuit may be used. Further, as the phase discriminator 93, a reference voltage and a comparator may be used.

  In the phase detection circuit 9 of FIG. 5, the phase discriminator 93 is omitted, and the phase detection circuit is configured only by the product-sum operation circuit composed of the multiplier 91 and the integrator 92, and an analog signal corresponding to the phase difference is output. You may make it do.

  Here, as the current or voltage of the phase detection portion, for example, the voltage or current of the inductor L1 of the resonance circuit 3, the voltage or current of the capacitor C1, the voltage or current of the capacitor C2, the voltage or current of the induction coil 2, or switching An instantaneous value of the current of the main electrode of the element Q2 is used.

  When the driving voltage Vgs of the switching element Q2 is used as the reference voltage of the phase detection circuit 9, the multiplier 91 multiplies “1” when the driving voltage Vgs is at a high level and “0” when the driving voltage Vgs is at a low level. As a result, the value obtained by averaging the current or voltage at the phase detection portion when the drive voltage Vgs is high level by the integrator 92 is compared with a predetermined level by the phase discriminator 93, and a binary signal is output. Will do.

  The multiplier 91 may multiply “0” when the drive voltage Vgs is at a high level and “1” when the drive voltage Vgs is at a low level. In this case, a value obtained by averaging the current or voltage of the phase detection portion when the drive voltage Vgs is at the low level by the integrator 92 is compared with a predetermined level by the phase discriminator 93, and a binary signal is output. .

  As the simplest configuration example, the phase is detected using the sum of the products of the instantaneous values for one cycle of the driving frequency of the driving voltage Vgs of the main electrode of the switching element Q2 and the instantaneous value of the output current of the power conversion circuit 4. With this configuration, the voltage obtained by averaging the detection voltage of the current detection resistor R1 when the drive voltage Vgs is at the high level or the low level by the CR integration circuit is compared with a predetermined reference voltage, so that the phase lag / advance is achieved. Can be judged.

  FIG. 6 shows the configuration of the fifth embodiment of the present invention. In the present embodiment, the phase detection circuit 9 is configured to detect the phase of the induction coil current. As described above, the phase detection circuit 9 is configured to detect the phase of the induction coil current, so that the resonance of the resonance system including the induction coil 2 can be accurately determined, and the power control can be performed more accurately. Thus, an electrodeless discharge lamp lighting device capable of performing the above can be obtained.

  FIG. 7 shows the configuration of Embodiment 6 of the present invention. In this embodiment, the capacitance element is connected in series to the induction coil 2 to form a series resonance circuit, and the control circuit 7 switches the switching elements Q1, Q2 so that the phase of the current of the series resonance circuit is delayed. The drive frequency is controlled.

  The induction coil 2 of the electrodeless discharge lamp lighting device has almost no resistance component before starting the lamp, and can be approximated by an equivalent circuit in which a resistor is connected in parallel after the lamp is lit.

In this embodiment, since the capacitance element is connected in series to the induction coil 2 to form a series resonance circuit, the phase of the series resonance circuit is delayed immediately after the lamp is turned on. By setting the operating point when the lamp is stable as a lag phase, the control circuit 7 controls the drive frequency of the switching elements Q1 and Q2 so that the phase of the current of the series resonant circuit becomes the lag phase. It is possible to operate with a lagging phase in all states before lighting, immediately after lighting, and stable lighting.
Thereby, the configuration of the control system is simplified, and a small and highly reliable electrodeless discharge lamp lighting device can be obtained.

  FIG. 8 shows the configuration of the seventh embodiment of the present invention. In this embodiment, the capacitance element is connected in parallel to the induction coil 2 to form a parallel resonance circuit, and the control circuit 7 controls the switching elements Q1 and Q2 so that the phase of the current of the parallel resonance circuit is advanced. The drive frequency is controlled. In this case, it is only necessary to detect the phase of the current of the parallel resonance circuit, and therefore, it is only necessary to detect a phase of less current than that of detecting the direct current of the induction coil 2. For this reason, a detection means becomes small and a small electrodeless discharge lamp lighting device can be obtained.

  FIG. 9 shows the configuration of the eighth embodiment of the present invention. In the present embodiment, when the detection value of the phase detection circuit 9 is different from the set phase value, the control circuit 7 temporarily sets the drive frequency to be larger than the set phase value in the direction of the set phase value. It is the structure which provided the means 12 which changes a frequency so that a change may be brought about.

  Specifically, a switch element S is provided in the control circuit 7, and when the indicated value of the phase detection circuit 9 is different from the set phase value, the switch element S is temporarily short-circuited to oscillate the drive circuit 6. The drive frequency is changed by temporarily changing the current flowing through the charge / discharge circuit of the capacitor that determines the frequency. When the phase shifts to a true phase state due to a temporary frequency change, the current detection circuit 8 that detects the current value of the main electrode of the switching element Q2 in the phase state becomes stable, and the required output power can be obtained. .

  The principle will be described with reference to FIG. For example, it is assumed that the part that should oscillate at the operating point b is operating at the operating point b ″. In this case, the detected value of the phase detection circuit 9 is different from the set phase value, and the main element of the switching element Q2 is near the frequency. Even if the control is performed so that the current value of the electrode matches the indicated value, the required output power is not obtained.If the phase value is different as described above, the required output power state is obtained unless the phase state is once exceeded. Therefore, in this case, the frequency is not changed in the direction close to the operating point b between the operating points b and b ″, but the frequency is further changed to a frequency higher than the operating point b. Shake it. From this state, when feedback control is performed by the current detection resistor R1, the operation point b is settled.

  As described above, in this embodiment, even when a false phase state occurs, it is possible to quickly return to the true phase state with a simple configuration, and to obtain a small and inexpensive electrodeless discharge lamp lighting device with less stress. I can do it.

  FIG. 10 shows the configuration of the ninth embodiment of the present invention. In the present embodiment, in the above-described eighth embodiment, the frequency changing means operates at regular intervals after the electrodeless discharge lamp 1 is started and after the electrodeless discharge lamp lighting device is in a temperature stable operation state. It is characterized by doing. For detecting that the temperature is substantially stable, a timer circuit 13 for measuring the time after starting the lamp is used. Thus, the frequency changing means is configured to operate at regular intervals after the electrodeless discharge lamp is started and after the electrodeless discharge lamp lighting device is in a temperature stable operation state. This makes it possible to accurately match the output power during stable lighting where the designed light output is required.

  In addition, by operating at regular intervals, in the event that it falls into a false phase state for any reason, an electrodeless discharge lamp lighting device that can get out of that state and stably output power is provided. Can be obtained.

  FIG. 11 is a flowchart for explaining the operation when the present embodiment is configured as a digital system. Here, the control circuit 7 is constituted by a microcomputer, and phase detection is performed at regular intervals using a timer interrupt. As a premise thereof, for example, the detection value of the current detection circuit 8 is fetched from the input port of the microcomputer every 1 ms, and the oscillation frequency f of the drive circuit 6 is feedback-controlled. If the detected current value is excessive, the oscillation frequency f is decreased by a minute amount δf, if it is excessively small, the oscillation frequency f is increased by a minute amount δf, and if appropriate, the oscillation frequency f is maintained. By counting the number of timer interruptions for this current feedback control, the phase is detected by the phase detection circuit 9 at regular intervals. If the detected phase is out of the set value, the oscillation frequency f of the drive circuit 6 is detected. Is changed to the high frequency side by a change amount ΔF (>> δf) sufficiently larger than the normal change width δf. As a result, even if it falls into a false phase state due to some reason, it is possible to get out of that state, and then to maintain a proper output stably by performing normal current feedback control. Can do.

  2 to 10 is not limited to a configuration in which a DC voltage is obtained from the commercial AC power supply Vs to the smoothing capacitor C0 via the rectifier bridge DB and the step-up chopper circuit 51, as shown in FIG. A simple capacitor input type rectifying and smoothing circuit may be used, or other chopper circuits or converter circuits may be used.

  INDUSTRIAL APPLICABILITY The present invention can be used as, for example, an outdoor or high-level lighting device as a long-life lighting device with high efficiency and low lamp replacement frequency.

It is a circuit diagram which shows the basic composition of this invention. It is a circuit diagram of Example 1 of the present invention. It is a circuit diagram of Example 2 of the present invention. It is a circuit diagram of Example 3 of the present invention. It is a circuit diagram of Example 4 of the present invention. It is a circuit diagram of Example 5 of the present invention. It is a circuit diagram of Example 6 of the present invention. It is a circuit diagram of Example 7 of the present invention. It is a circuit diagram of Example 8 of the present invention. It is a circuit diagram of Example 9 of the present invention. It is a flowchart which shows operation | movement of Example 9 of this invention. It is a circuit diagram of the conventional discharge lamp lighting device. It is explanatory drawing which shows the load characteristic of the conventional discharge lamp lighting device. It is a circuit diagram of the conventional electrodeless discharge lamp lighting device. It is explanatory drawing which shows the load characteristic of the conventional electrodeless discharge lamp lighting device. It is a wave form diagram for demonstrating the subject of the conventional electrodeless discharge lamp lighting device. It is sectional drawing which illustrates the structure of the electrodeless discharge lamp used for the non-discharge discharge lamp lighting device of this invention. It is sectional drawing which illustrates the structure of the illuminating device using the electrodeless discharge lamp lighting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrodeless discharge lamp 2 Inductive coil 3 Resonant circuit 4 Power conversion circuit 5 Power supply circuit 6 Drive circuit 7 Control circuit 8 Current detection circuit 9 Phase detection circuit

Claims (5)

An induction coil wound in the vicinity of an electrodeless discharge lamp, a resonance circuit connected to the induction coil and including an inductance element and a capacitance element, a power conversion circuit including a switching element and connected to the resonance circuit, and the power A power supply circuit that supplies power to the conversion circuit, a drive circuit that drives the switching element, a control circuit that changes the drive frequency of the switching element by the drive circuit, and a current value of the main electrode of the switching element In an electrodeless discharge lamp lighting device comprising a current detection circuit, a phase detection circuit for detecting a phase of a current or voltage of the resonance circuit, the power conversion circuit, or the induction coil is provided, and the control circuit has a predetermined indication value And the switching element according to the detection output of the phase detection circuit and the detection output of the current detection circuit. An electrodeless discharge lamp lighting device and controls the drive frequency. The electrodeless discharge lamp lighting device according to claim 1, wherein the phase detection circuit detects a phase based on a driving voltage of the switching element or a main electrode terminal voltage of the switching element. The phase detection circuit uses the driving voltage of the switching element or the main electrode terminal voltage of the switching element as a reference voltage, and uses the instantaneous value of the current or voltage at the phase detection portion at the time of rising or falling of the reference voltage. The electrodeless discharge lamp lighting device according to claim 1, wherein the electrodeless discharge lamp lighting device is detected. The phase detection circuit uses a drive voltage of the switching element or a main electrode terminal voltage of the switching element as a reference voltage, and a product of an instantaneous value corresponding to one cycle of the drive frequency of the reference voltage and the current or voltage of the phase detection portion. The electrodeless discharge lamp lighting device according to claim 1, wherein the phase is detected using a sum. An illuminating device provided with the electrodeless discharge lamp lighting device in any one of Claims 1-4.

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