JP4543646B2 - High pressure discharge lamp lighting device and lighting device - Google Patents

Description

  The present invention relates to a high-pressure discharge lamp lighting device and an illumination device for high-frequency lighting of a high-pressure discharge lamp.

  Generally, a discharge lamp lighting device includes an LC resonance type inverter circuit, and when the discharge lamp is started, the inverter circuit starts oscillating at a high frequency and gradually decreases the frequency to approach the resonance frequency of the LC resonance circuit. As a result, the secondary voltage of the inverter circuit increases, and when the secondary voltage reaches the starting voltage of the discharge lamp, the discharge lamp starts to discharge and lights up. Once the discharge lamp is lit, the frequency of the inverter circuit is further lowered, and the discharge lamp is continuously lit at a stable lighting frequency (frequency at lighting).

  In the case of a high-pressure discharge lamp, since it has a characteristic that the discharge starts from the glow discharge to the arc discharge, it is necessary to apply a high secondary voltage for a predetermined time for the arc discharge transition. Therefore, the booster circuit provided in the previous stage of the inverter circuit controls the output voltage value to be higher than that during lighting when the high-pressure discharge lamp is started (see Patent Document 1). When the high pressure discharge lamp is lit, the lamp power is adjusted to be close to the rated power value by the output voltage of the booster circuit.

On the other hand, since the high-pressure discharge lamp has a frequency region in which acoustic resonance occurs, it is lit at a stable window frequency at which acoustic resonance does not occur during startup and lighting. And the sphericity of the discharge vessel of the discharge lamp is formed into a sphere having a sphericity of 0.53 to 0.84 and an inner diameter of 2.0 to 6.0 mm, and has a plurality of frequency regions (stable windows) that do not cause acoustic resonance. A high-pressure discharge lamp is provided (see Patent Document 2).
Japanese Unexamined Patent Publication No. 2000-58284 Japanese Patent Laid-Open No. 2002-42732

  However, when the high-pressure discharge lamp is started, the booster circuit supplies a higher voltage to the inverter circuit than when the high-pressure discharge lamp is lit. When the high-pressure discharge lamp is lit, the lamp power is adjusted to around the rated power value by adjusting the output voltage of the booster circuit. Therefore, a booster circuit is required for high-frequency lighting of the high-pressure discharge lamp. Therefore, it causes an increase in cost and an increase in size.

  An object of the present invention is to provide a high pressure discharge lamp lighting device capable of appropriately controlling lamp power without using a booster circuit.

A high pressure discharge lamp lighting device according to a first aspect of the present invention includes a rectifying / smoothing circuit that converts an alternating voltage into a direct current voltage; A first lighting in a first stable window in which acoustic resonance of the high-pressure discharge lamp does not occur in one cycle of a predetermined PWM frequency so that the lamp power of the high-pressure discharge lamp becomes a predetermined value A PWM control circuit for controlling a ratio between the frequency and the second lighting frequency in the second stable window; and switching the first lighting frequency and the second lighting frequency at a ratio controlled by the PWM control circuit; an inverter control circuit for switching control; wherein the PWM control circuit, the lamp voltage of the high-pressure discharge lamp is put into a single lighting frequency in the first stability window And performs PWM control at maximum power when the lamp voltage the range of the inverter load characteristics.

  In the present invention and the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified. The rectifying / smoothing circuit is configured, for example, by connecting a smoothing capacitor in parallel to a rectifier of a diode bridge, and converts a commercial AC voltage into a DC voltage, such as a full-wave rectification type, a double voltage rectification type, and a partial smoothing type. Either of these is acceptable. The inverter circuit supplies high-frequency power to the high-pressure discharge lamp through a resonance circuit based on the DC voltage obtained by the rectifying / smoothing circuit. For example, the inverter circuit has two switch elements, and the DC voltage from the rectifying / smoothing circuit. As an input, the two switch elements are alternately turned on and off from the inverter control circuit to output a high-frequency voltage on the output side, and a resonance circuit is connected to the high-pressure discharge lamp connected to the output side of the inverter circuit. High frequency power is supplied through In addition to the half-bridge type, a constant current push-pull type, one-stone type, full-bridge type inverter circuit may be used.

  The high-pressure discharge lamp is a mercury lamp, a metal halide lamp, a high-pressure sodium lamp, or the like, and also includes a ceramic discharge lamp using an alumina tube as an arc tube. The resonance circuit includes an inductor and a capacitor, and generates a high voltage in the vicinity of the resonance frequency of the resonance circuit according to the frequency of the high-frequency voltage input from the inverter circuit.

The PWM control circuit controls the ratio between the first lighting frequency of the first stable window where the acoustic resonance of the high pressure discharge lamp does not occur and the second lighting frequency in the second stable window, and the lamp power of the high pressure discharge lamp. The ratio between the first lighting frequency of the first stable window and the second lighting frequency in the second stable window is determined so that becomes a predetermined value. As a general method, when lighting in the slow phase region, the lamp power decreases when the lighting frequency is high, and the lamp power increases when the lighting frequency is low. The lamp power can be increased by decreasing the ratio of the low frequencies.
Further, when the LC resonance type inverter is operated at a constant frequency, it has a load curve in which the maximum power is obtained at a certain lamp voltage value, and the lamp power is zero in a load short circuit and secondary open state. At the first lighting frequency in the first stable window, the higher the lamp voltage, the faster the phase oscillation occurs, and the efficiency may deteriorate due to the switching loss of the inverter circuit.
Therefore, the PWM control circuit performs PWM control in a range where the lamp voltage of the high-pressure discharge lamp is equal to or lower than the voltage at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. When lighting the high-pressure discharge lamp having, it is lit at the lighting frequency of the second stable window having a high lighting frequency.

  The inverter control circuit performs switching control of the inverter circuit at the first lighting frequency in the first stable window and the second lighting frequency in the second stable window. The ratio between the first lighting frequency and the lighting frequency in the second stable window is a ratio determined by the PWM control circuit.

According to the present invention, since the lamp power is controlled by adjusting the ratio of lighting at the first lighting frequency in the first stable window and the second lighting frequency in the second stable window, the booster circuit is not necessary, and the cost is reduced. And simplification and miniaturization of the device. Further, even when a high-pressure discharge lamp having a high lamp voltage is lit, it is possible to prevent phase advance oscillation during PWM control, and it is possible to prevent efficiency from deteriorating due to switching loss.

According to a second aspect of the present invention, there is provided a high pressure discharge lamp lighting device comprising: a rectifying / smoothing circuit for converting an AC voltage into a DC voltage; A first lighting in a first stable window in which acoustic resonance of the high-pressure discharge lamp does not occur in one cycle of a predetermined PWM frequency so that the lamp power of the high-pressure discharge lamp becomes a predetermined value A PWM control circuit that controls a ratio between the frequency and the second lighting frequency at which acoustic resonance occurs; and switches between the first lighting frequency and the second lighting frequency at which acoustic resonance occurs at a ratio controlled by the PWM control circuit; An inverter control circuit for controlling the switching of the inverter circuit , wherein the PWM control circuit is configured such that the lamp voltage of the high-pressure discharge lamp is the first stable The PWM control is performed in a range equal to or lower than the lamp voltage at the maximum power in the inverter load characteristic at a single lighting frequency in the window .

  According to the present invention, PWM control is performed using the second lighting frequency at which acoustic resonance occurs instead of the second lighting frequency of the second stable window of the first aspect of the invention, and the lamp power of the high-pressure discharge lamp is controlled to a predetermined value. It is what you do.

  When PWM control of two lighting frequencies is performed by the PWM control circuit, if one lighting frequency is the lighting frequency of the stable window, even if the other lighting frequency is the lighting frequency at which acoustic resonance occurs, the arc No bend or flicker. According to the present invention, when the high-pressure discharge lamp has at least one stable window region, it is possible to perform constant lamp power control by PWM control, so that the application range is expanded. Further, when the lamp current at the first lighting frequency in the first stable window is larger than the lamp current at the second lighting frequency, arc bending or flickering of the high-pressure discharge lamp is less likely to occur, and can be set as such. preferable.

A high pressure discharge lamp lighting device according to a third aspect of the present invention is the high pressure discharge lamp lighting device according to the first or second aspect , wherein the no-load resonant frequency of the resonant circuit is set to 2 to 3 times the first lighting frequency in the first stable window. The PWM control circuit performs PWM control in a range below the lamp voltage when the lamp voltage of the high-pressure discharge lamp becomes a predetermined lamp power value in the inverter load characteristic at the second lighting frequency.

  When the inductor and capacitor of the resonance circuit are set so that the no-load resonance frequency of the high-pressure discharge lamp is between 2 and 3 times the oscillation frequency when the high-pressure discharge lamp is lit, the first lighting frequency in the first stable window However, even if the lamp voltage is increased, the switching waveform of the inverter is in a third-order resonance state and does not lead to phase advance oscillation. Therefore, PWM control is performed even for a high-pressure discharge lamp having a lamp voltage equal to or higher than the lamp voltage at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. In this case, the PWM control circuit performs PWM control in a range equal to or lower than the lamp voltage when the lamp voltage of the high-pressure discharge lamp becomes a predetermined lamp power value in the inverter load characteristic at the second lighting frequency. This is because the lamp power cannot be controlled to a predetermined value if the lamp voltage is equal to or higher than the predetermined value of the lamp power in the inverter load characteristic at the second lighting frequency.

  According to the present invention, PWM control can be performed even for a high-pressure discharge lamp having a lamp voltage equal to or higher than the lamp voltage at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. The range of control can be widened.

A lighting device according to a fourth aspect of the present invention is a high pressure discharge lamp lighting device according to any one of the first to third aspects; a high pressure discharge lamp that is lit by the high pressure discharge lamp lighting device; and the high pressure discharge lamp. An instrument body to be mounted; and According to the present invention, an illumination device having the effect of any one of claims 1 to 3 can be obtained.

According to the first aspect of the present invention, since the lamp power is controlled by adjusting the ratio of lighting at the first lighting frequency in the first stable window and the lighting frequency in the second stable window, a booster circuit is not required, and the cost is reduced. Down, simplification and downsizing of the device can be achieved. Further, even when a high-pressure discharge lamp having a high lamp voltage is lit, it is possible to prevent phase advance oscillation during PWM control, and it is possible to prevent efficiency from deteriorating due to switching loss.

According to the second aspect of the present invention, when the high-pressure discharge lamp has at least one stable window region, the lamp power constant control by the PWM control becomes possible, so the applicable range is widened.

According to the invention of claim 3 , PWM control can be performed even for a high-pressure discharge lamp having a lamp voltage equal to or higher than the lamp voltage at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. The range of PWM control can be widened. According to invention of Claim 4, the illuminating device which has an effect of any one of Claim 1 thru | or 12 is obtained.

  An embodiment of the present invention will be described. FIG. 1 is a configuration diagram of a high-pressure discharge lamp lighting device 11 according to a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of an example of a high-pressure discharge lamp 12 used in the first embodiment of the present invention. .

  In FIG. 2, the high-pressure discharge lamp 12 is a ceramic discharge lamp using an alumina tube as the arc tube 13, and the arc tube 13 is made of translucent alumina. The arc tube 13 of the ceramic discharge lamp is chemically and thermally more stable with respect to the metal halide as the enclosure than the quartz glass used in the arc tube of the general high-pressure discharge lamp 12. The arc tube 13 is housed in an outer tube 14 whose inside is kept in vacuum, and a base 15 is provided at one end of the outer tube 14. A high-frequency voltage is applied from the high-pressure discharge lamp lighting device 11 between the tip portion 15a of the base 15 and the screw portion 15b.

  The sphericity of the arc tube 13 of the high-pressure discharge lamp designed for such high-frequency lighting is 0.53 to 0.84, and has a plurality of frequency regions (stable windows) that do not cause acoustic resonance. For example, a ceramic metal halide lamp designed for 20 W has a distance between electrodes of 3.6 mm within the arc tube 13 and an inner diameter of 6 mm, and the main stable windows are 0 kHz to 20 kHz, 40 kHz to 50 kHz, and 80 kHz to 88 kHz. .

  Next, the high pressure discharge lamp lighting device 11 for lighting such a high pressure discharge lamp 12 will be described. FIG. 1 is a block diagram of a high pressure discharge lamp lighting device 11. The AC voltage from the AC power supply 16 is input to the rectifying / smoothing circuit 17 of the high-pressure discharge lamp lighting device 11 and converted into a DC voltage. The DC voltage obtained by the rectifying / smoothing circuit 17 is input to the inverter circuit 18, converted into a high-frequency voltage by turning on and off the switching elements of the inverter circuit 18, and high-frequency power is supplied to the high-pressure discharge lamp 12 through the resonance circuit 19.

  The inverter circuit 18 is configured as a half-bridge type that has two switch elements and outputs a high-frequency voltage on the output side by alternately turning on and off the two switch elements with the DC voltage from the rectifying and smoothing circuit 17 as an input. The The resonance circuit 19 includes an inductor and a capacitor, and generates a high voltage near the resonance frequency of the resonance circuit 19 according to the frequency of the high-frequency voltage input from the inverter circuit 18 when the high-pressure discharge lamp 12 is started. The high pressure discharge lamp 12 is turned on.

  The PWM control circuit 20 inputs the lamp power of the high-pressure discharge lamp 12 converted from the lamp voltage and lamp current detected by the lamp power detection circuit 21, and the high-pressure discharge lamp 12 is controlled so that the lamp power becomes a predetermined value. PWM control is performed on the ratio between the first lighting frequency in the first stable window and the lighting frequency in the second stable window where no acoustic resonance occurs. The inverter control circuit 22 performs switching control of the inverter circuit 18 by switching between the first lighting frequency in the first stable window and the lighting frequency in the second stable window at a predetermined PWM frequency. Here, the PWM control circuit 20 detects that switching of the inverter circuit 18 has been performed and starts operation. This is because the control power of the PWM control circuit 20 is supplied after the oscillation of the inverter circuit 18 is started. Thereby, the lamp power from the start to the stable lighting can be changed.

  FIG. 3 is an explanatory diagram of a stability window when a ceramic metal halide lamp designed for 20 W is lit with a sine wave. As shown in FIG. 3, it has a frequency range of 0 kHz to 20 kHz, 40 kHz to 50 kHz, and 80 kHz to 88 kHz as a plurality of frequency regions (stable windows) that do not cause acoustic resonance. Now, assume that 40 kHz to 50 kHz is selected as the first stable window and 80 kHz to 88 kHz is selected as the second stable window. Then, 45 kHz which is the median value of the first stable window is set as the first lighting frequency, and 84 kHz which is the median value of the second stable window is selected as the second lighting frequency. Then, the PWM control circuit 20 determines the ratio of operating time at the first lighting frequency 45 kHz and the second lighting frequency 84 kHz so that the lamp power of the high-pressure discharge lamp 12 becomes a predetermined value.

  FIG. 4 is an explanatory diagram of the ratio of the first lighting frequency 45 kHz and the second lighting frequency 84 kHz in one period T with the PWM frequency, and FIG. 5 is a characteristic diagram of the lamp power and the lighting frequency. As shown in FIG. 4, within a predetermined PWM cycle T, a lamp current having a first lighting frequency of 45 kHz and a lamp current having a second lighting frequency of 84 kHz are mixed, and the first lighting frequency of 45 kHz and the second lighting frequency are mixed. Change the ratio of time to operate at 84 kHz. As shown in FIG. 5, the lamp power W45 is large at the first lighting frequency 45 kHz where the lighting frequency is low, and the lamp power W84 is small at the second lighting frequency 84 kHz where the lighting frequency is high. This is because the lamp power can be adjusted by changing the ratio of the operating time at the second lighting frequency of 84 kHz.

  Here, the PWM frequency that defines the predetermined PWM cycle T is set to 100 Hz or more and less than the first lighting frequency. The reason why the PWM frequency is set to 100 Hz or more is to prevent the visual sensitivity from responding to the ripple of the lamp current and to avoid flickering. Moreover, the reason why the frequency is less than the first lighting frequency is to allow the lamp power to be appropriately controlled.

  In the above description, the first lighting frequency is 45 kHz and the second lighting frequency is 84 kHz. However, the first lighting frequency may be 18 kHz, the second lighting frequency may be 45 kHz, and the first lighting frequency is 18 kHz. The second lighting frequency may be 84 kHz.

  FIG. 6 is a characteristic diagram of the secondary voltage and frequency of the inverter circuit 18 when there is no load in the first embodiment. In the first embodiment, the lighting frequency of 84 kHz in the second stable window is substantially matched with the no-load resonance frequency of the resonance circuit 19. Since the frequency of 84 kHz at which the lamp power decreases becomes substantially equal to the no-load resonance frequency of the resonance circuit 19, a sufficiently high secondary voltage can be generated even when the lamp power is small and the high-pressure discharge lamp 12 is likely to disappear. Therefore, the high pressure discharge lamp 12 can be stably lit without being extinguished.

  Further, when the high-pressure discharge lamp 12 is started, the high-pressure discharge lamp 12 is operated at a frequency within the second stable window, near the no-load resonance frequency of the resonance circuit 19 and at a slow phase frequency. Oscillation starts in the slow frequency region of the resonance circuit 19, a high pressure is generated at the resonance frequency of the resonance circuit 19 (frequency near the lighting frequency of 84 kHz), and the high-pressure discharge lamp 12 is started. Immediately after start-up, the frequency is in the vicinity of the lighting frequency of 84 kHz. Therefore, the frequency is within the stable window even immediately after start-up, and no stress is applied to the arc tube 13 of the high-pressure discharge lamp 12 due to arc bending or the like.

  In the above description, the lighting frequency of the PWM control performed by the PWM control circuit 20 is the same as the stable window frequency (45 kHz, 84 kHz), but acoustic resonance other than the stable window occurs at one lighting frequency. A frequency may be used. In this case, the frequency causing the acoustic resonance is higher than the lighting frequency of the stable window. For example, when the first lighting frequency of 45 kHz in the first stable window is selected, 90 kHz or higher higher than that is selected as the second lighting frequency causing acoustic resonance.

  FIG. 7 shows that for a spherical high-pressure discharge lamp having a sphericity of 0.53 to 0.84 and an inner diameter of 2.0 to 6.0 mm, the first lighting frequency in the first stable window is 45 kHz, When the second lighting frequency is 90 kHz (unstable window), the ratio (stable window frequency ratio) (%) between the first lighting frequency in the first stable window and the second lighting frequency at which acoustic resonance occurs, and the lamp voltage It is a characteristic view with VL and lamp electric power WL.

  As shown in FIG. 7, when the stable window frequency ratio is 0% to 10% (when the lighting frequency 90 kHz causing acoustic resonance is included 100% to 90%), the lamp voltage VL exhibits a characteristic that changes sharply. When the stable window frequency ratio is 10% or more, the lamp voltage VL has a substantially constant characteristic. The lamp power WL exhibits a substantially constant characteristic when the stable window frequency ratio is 10% or more. Therefore, for a spherical high pressure discharge lamp having a sphericity of 0.53 to 0.84 and an inner diameter of 2.0 to 6.0 mm, the stable window frequency ratio is set to a range of 100% to 10%. can do.

  FIG. 8 shows a case where the first lighting frequency in the first stable window is 45 kHz and the second lighting frequency is changed from 75 kHz to 110 kHz for a high pressure discharge lamp having a sphericity of the discharge vessel of less than 0.53. It is a characteristic figure of stability limit ratio (%). When the second lighting frequency is 75 kHz to 82 kHz, the stability limit ratio is 80% to 65%, indicating that it is necessary to include the stable window frequency 45 kHz of 80% to 65%. Similarly, when the second lighting frequency is 86 kHz to 110 kHz, the stability limit ratio is 55% to 10%, indicating that it is necessary to include 55% to 10% of the stable window frequency 45 kHz. When the second lighting frequency is 82 kHz to 86 kHz, the stability limit ratio is 0%, and the stable window frequency 45 kHz may be 0%. This is because the frequency of 82 kHz to 86 kHz is the second stable window of the high pressure discharge lamp used for the measurement. Thus, for the high-pressure discharge lamp having a sphericity of the discharge vessel of less than 0.53, the stable window frequency ratio varies depending on the second lighting frequency causing acoustic resonance, but the second lighting frequency is 100 kHz or more, When the lamp power when operating at the second lighting frequency is set small, the stable window frequency ratio can be 10%. From this, the second lighting frequency may be set high in a range where the lamp does not go out without focusing on the LC resonance point, and the stable window frequency ratio can be set in the range of 100% to 10%.

  Further, when the ratio of the lamp power W1 at the first lighting frequency and the lamp power W2 at the second lighting frequency is W1 / W2 ≧ 2.0, the lamp power can be made constant with a smaller PWM change width. That is, since the ratio of lighting at the first stable window is increased, more stable lighting is possible.

  Next, control power supplies for the PWM control circuit 20 and the inverter control circuit 22 will be described. The PWM control circuit 20 and the inverter control circuit 22 are configured to have individual control power supplies. Then, after the inverter control circuit 22 is activated, the PWM control circuit 20 is started to operate.

  The PWM control circuit 20 selects the high frequency of the second stable window or the second lighting frequency when the lamp voltage becomes a certain value or more according to the detection value of the lamp power detection circuit, so that the PWM control circuit 20 operates. However, it is possible to start the high-pressure discharge lamp. On the other hand, if the second lighting frequency is selected immediately after the high pressure discharge lamp is started, there may be a case where the power that can be supplied to the high pressure discharge lamp is small. If the power supplied to the high-pressure discharge lamp is small immediately after starting, the electrode may not be heated sufficiently and electrode sputtering may continue for a long time.

  Therefore, the inverter control circuit 22 starts the high pressure discharge lamp, and after the high pressure discharge lamp is stably lit at the first stable window frequency, the PWM control circuit 20 is started. The operation timings of the inverter control circuit 22 and the PWM control circuit 20 are managed at the rise of each individual control power supply.

  FIG. 9 is an explanatory diagram of the control power supply of the inverter control circuit 22. In FIG. 9, the control power supply of the inverter control circuit 22 is supplied from the switching snubber circuit 27 of the inverter circuit 18. A switching snubber circuit 27 is provided at a series connection point of the two switch elements S1 and S2 of the inverter circuit 18. The switching snubber circuit 27 is composed of a capacitor C1 and reduces the switching loss by giving a slope to the voltage rise during the on / off operation of the switch elements S1 and S2. And in order to take out the control power supply of the inverter control circuit 22, the capacitor | condenser C2 is provided through the diodes D1 and D2. In the switching snubber circuit 27, when the switching element S1 of the inverter circuit 18 is turned on and S2 is turned off and a voltage is applied to the switching element S2, the capacitor C1 and the capacitor C2 are charged, and a voltage is generated across the capacitor C2. From this, it is possible to trigger the operation timing of the inverter control circuit 22 by generating the voltage of the capacitor C2. Therefore, the inverter control circuit 22 is started after the oscillation starts. The inverter control circuit starts oscillation of the switching elements S1 and S2 by the resistor R1, and thereafter obtains a control power source stably from the switching snubber circuit 27.

  FIG. 10 is an explanatory diagram of the control power supply of the PMW control circuit 20. In FIG. 10, the control power supply of the PWM control circuit 20 is supplied from the charge / discharge circuit 28 of the smoothing capacitor of the rectifying and smoothing circuit 17. The rectifying / smoothing circuit 17 rectifies the alternating current from the alternating current power supply 16 into direct current with the diodes D11, D12, and smoothes it with the smoothing capacitors C11, C12, C13. And in order to take out the control power supply of the PWM control circuit 20, the capacitor | condenser C14 is provided through the diodes D13 and D14. Since the charging / discharging currents of the smoothing capacitors C11, C12, C13 of the rectifying / smoothing circuit 17 increase after the consumption current of the inverter circuit 18 becomes large, the voltage of the capacitor C14 also becomes PWM after the consumption current of the inverter circuit 18 becomes large. A voltage large enough to start the control circuit is generated. Therefore, the control power supply that can be supplied from the capacitor C14 can be supplied after the consumption current of the inverter circuit 18 becomes large, and can be used as a trigger for the operation timing of the PWM control circuit 20. That is, the PWM control circuit 20 is started after the power consumption of the high-pressure discharge lamp serving as the load of the inverter circuit 18 becomes relatively large.

  Here, instead of supplying the control power of the PWM control circuit 20 from the smoothing capacitor charge / discharge circuit 28 of the rectifying and smoothing circuit 17, the current of the capacitor of the resonance circuit 19 may be used as the control power of the PWM control circuit 20. Is possible. In this case, since the current of the capacitor of the resonance circuit 19 rises at the start, a delay circuit is provided to delay the operation of the PWM control circuit. As described above, since the control power of the inverter control circuit 22 and the PWM control circuit 20 can be supplied from the circuit constituting the high pressure discharge lamp lighting device, the control power can be stably supplied without complicating the circuit configuration. .

  Next, the range in which the PWM control circuit 20 performs PWM control will be described. In order to prevent phase advance oscillation during lighting, the PWM control circuit 20 causes the lamp voltage of the high pressure discharge lamp to be equal to or lower than the lamp voltage at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. PWM control is performed only within the range. Above the maximum power, it is operated only at the second lighting frequency.

  FIG. 11 is a characteristic diagram of a load characteristic curve of the inverter circuit 18. The vertical axis represents the lamp power WL, the horizontal axis represents the lamp voltage VL, the 45 kHz characteristic curve S1 when operated at 45 kHz of the first lighting frequency in the first stable window, the lighting frequency of the second stable window, or the second An 84 kHz characteristic curve S2 when operating at a lighting frequency of 84 kHz (no-load resonance frequency) is shown. When operating at the first lighting frequency of 45 kHz in the first stable window, the characteristic is along the 45 kHz characteristic curve S1, and as shown in FIG. 12, the lamp voltage VL is increased and at 150V and 200V exceeding 100V, Phased oscillation has been reached.

  Therefore, as shown in FIG. 13, PWM control is performed in a range where the lamp voltage VL of the high-pressure discharge lamp is not more than the lamp voltage (100 V) at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. . FIG. 13 shows a case where PWM control is performed between 50V and 100V. When the lamp power level at which the PWM control circuit 20 starts operating is set to about 17 W, the PWM control circuit 20 repeats the operation / non-operation during V11, so that a constant power region of about 17 W appears. The PWM control circuit 20 operates ideally at a lamp voltage of 50V to 100V. Then, the lamp voltage VL equal to or higher than the lamp voltage (100 V) at the maximum power is controlled along the 84 kHz characteristic curve S2. That is, it controls by the lighting frequency of the 2nd stable window with a high lighting frequency, or the 2nd lighting frequency. Thereby, it is possible to prevent phase-advanced oscillation during lighting, and it is possible to prevent efficiency from deteriorating due to switching loss.

  Here, when the no-load resonance frequency of the resonance circuit 19 is set to 2 to 3 times the first lighting frequency 45 kHz in the first stable window, even if the lamp voltage VL is increased, the third resonance state is set and the phase is advanced. Since it does not oscillate, slow phase switching is possible.

  FIG. 14 is a characteristic diagram of the load characteristic curve of the inverter circuit 18 when the no-load resonance frequency is set to 2 to 3 times the first lighting frequency 45 kHz in the first stable window. The vertical axis represents the lamp power WL, the horizontal axis represents the lamp voltage VL, the 45 kHz characteristic curve S1 when operated at the first lighting frequency of 45 kHz in the first stable window, and the second lighting frequency of 100 kHz (no load resonance). 100 kHz characteristic curve S3 when operating at a frequency). When operating at a first lighting frequency of 45 kHz in the first stable window, the characteristic is along the 45 kHz characteristic curve S1, and as shown in FIG. 15, the lamp voltage VL increases and exceeds 150V, such as 150V and 200V. Then, the switching current is in the third-order resonance state, and does not lead to phase advance oscillation.

  Therefore, PWM control is performed even when a high-pressure discharge lamp having a lamp voltage of 100 V or higher at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window is lit. The 100 kHz characteristic curve S3 has a predetermined lamp power value when the lamp voltage VL reaches 170V. Therefore, the upper limit of the PWM control in the PWM control circuit 20 is that the lamp voltage VL is up to 170V. When the lamp voltage VL is higher than this, there is a problem that the lamp power cannot be controlled to a predetermined value. Thus, when the no-load resonance frequency is set to 2 to 3 times the first lighting frequency 45 kHz in the first stable window, the lamp at the maximum power in the inverter load characteristic at the first lighting frequency in the first stable window. Even a high-pressure discharge lamp having a lamp voltage higher than the voltage can perform PWM control, and the range of PWM control can be widened.

  FIG. 16 is an explanatory diagram of a lighting apparatus according to the second embodiment of the present invention. The high-pressure discharge lamp lighting device 11 according to the first embodiment constitutes an illumination device together with the appliance main body 23 to which the high-pressure discharge lamp 12 is attached. As shown in FIG. 16, the high-pressure discharge lamp 12 is mounted on the socket 24 of the instrument body 23 and is lit by the high-pressure discharge lamp lighting device 11. Light from the lit high-pressure discharge lamp 12 is reflected by the front reflector 25 and irradiated through the front glass 26. According to the illumination device of the second embodiment, the illumination device having the effect of the high-pressure discharge lamp lighting device 11 in the first embodiment can be obtained.

1 is a configuration diagram of a high-pressure discharge lamp lighting device according to a first embodiment of the present invention. Explanatory drawing of an example of the high pressure discharge lamp used in the 1st Embodiment of this invention. Explanatory drawing of the stable window in the ceramic metal halide lamp designed for 20W. Explanatory drawing of the ratio of the 1st lighting frequency 45kHz and the 2nd lighting frequency 84kHz in one period T with a PWM frequency. The characteristic figure of lamp electric power and lighting frequency. The characteristic diagram of the secondary voltage and frequency of an inverter circuit at the time of no load in the 1st Embodiment of this invention. The characteristic figure of a stable window frequency ratio, lamp voltage, and lamp electric power. The characteristic diagram of the stability limit ratio and 2nd lighting frequency of a high pressure discharge lamp with small sphericity. Explanatory drawing of the control power supply of an inverter control circuit. Explanatory drawing of the control power supply of a PMW control circuit. The characteristic figure of the load characteristic curve of an inverter circuit. The characteristic diagram of phase advance oscillation. Explanatory drawing of an example of PWM control. The characteristic figure of the load characteristic curve of an inverter circuit at the time of setting a no-load resonant frequency to 2 to 3 times the 1st lighting frequency in a 1st stable window. The characteristic view of a tertiary resonance state. Explanatory drawing of the illuminating device which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... High pressure discharge lamp lighting device, 12 ... High pressure discharge lamp, 13 ... Light-emitting tube, 14 ... Outer tube, 15 ... Base, 16 ... AC power supply, 17 ... Rectification smoothing circuit, 18 ... Inverter circuit, 19 ... Resonance circuit, 20 DESCRIPTION OF SYMBOLS ... PWM control circuit, 21 ... Lamp power detection circuit, 22 ... Inverter control circuit, 23 ... Appliance main body, 24 ... Socket, 25 ... Reflector plate, 26 ... Front glass, 27 ... Switching snubber circuit, 28 ... Charge / discharge circuit

Claims (4)

A rectifying / smoothing circuit for converting AC voltage into DC voltage;
An inverter circuit for supplying high-frequency power to a high-pressure discharge lamp via a resonance circuit based on a DC voltage obtained by the rectifying and smoothing circuit;
The first lighting frequency in the first stable window and the second stable window in which the acoustic resonance of the high pressure discharge lamp does not occur in one cycle of the predetermined PWM frequency so that the lamp power of the high pressure discharge lamp becomes a predetermined value. A PWM control circuit for controlling a ratio of the second lighting frequency to the second lighting frequency;
An inverter control circuit that performs switching control of the inverter circuit by switching between a first lighting frequency and a second lighting frequency at a ratio controlled by the PWM control circuit;
The PWM control circuit performs PWM control in a range where the lamp voltage of the high-pressure discharge lamp is less than or equal to the lamp voltage at the maximum power in the inverter load characteristic at a single lighting frequency in the first stable window. A high pressure discharge lamp lighting device. A rectifying / smoothing circuit for converting AC voltage into DC voltage;
An inverter circuit for supplying high-frequency power to a high-pressure discharge lamp via a resonance circuit based on a DC voltage obtained by the rectifying and smoothing circuit;
The first lighting frequency in the first stable window and the acoustic resonance are generated in one cycle of the predetermined PWM frequency so that the lamp power of the high pressure discharge lamp becomes a predetermined value. A PWM control circuit for controlling the ratio to the second lighting frequency;
An inverter control circuit that performs switching control of the inverter circuit by switching between the first lighting frequency and the second lighting frequency at which acoustic resonance occurs at a ratio controlled by the PWM control circuit;
The PWM control circuit performs PWM control in a range where the lamp voltage of the high-pressure discharge lamp is less than or equal to the lamp voltage at the maximum power in the inverter load characteristic at a single lighting frequency in the first stable window. A high pressure discharge lamp lighting device. The no-load resonance frequency of the resonance circuit is set to 2 to 3 times the first lighting frequency, and the PWM control circuit determines a lamp power at an inverter load characteristic at a lamp voltage of the high-pressure discharge lamp at a second lighting frequency. The high-pressure discharge lamp lighting device according to claim 1 or 2, wherein PWM control is performed in a range that is equal to or less than a lamp voltage when the value is reached. A high pressure discharge lamp lighting device according to any one of claims 1 to 3;
A high pressure discharge lamp to be lit by the high pressure discharge lamp lighting device;
An instrument body to which the high-pressure discharge lamp is mounted;
An illumination device comprising:

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