JP2003036991A - Discharge lamp lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which electric power loss is reduced while the control action is made stable. SOLUTION: A boost chopper circuit 14 and an inverter circuit 15 are connected with a commercial alternating-current power supply (e) via a full wave rectification circuit 12. In order to make a lamp current of a fluorescent lamp FL constant, the output voltage of the boost chopper circuit 14 is controlled by an integrator 25. The lowest pole frequency of the integrator 25 of the control circuit 21 is set higher than the lowest pole frequency of the whole loop transfer function of the discharge lamp lighting device 5. The response in the vicinity of the lowest pole frequency of the loop transfer function is taken as the primary delay, and the turn round of the phase is made smaller and the phase margin is made larger, thereby the action is made to be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device and a lighting device having a boost chopper circuit and an inverter circuit.

[0002]

2. Description of the Related Art Heretofore, as a discharge lamp lighting device of this type, a structure disclosed in, for example, Japanese Patent Laid-Open No. 10-243661 has been known. In this Japanese Unexamined Patent Publication No. 10-243661, a half bridge type inverter circuit in which a pair of switching elements are connected in series is connected to a DC power source, and a capacitor and a switching element on the stable potential side of the inverter circuit are connected. One end of each filament of the fluorescent lamp is connected via an inductor, and a capacitor is connected between the other ends of these filaments to form a resonant load circuit.

The deflection angle arg (Z) of the resonant load circuit seen from the inverter circuit is 0 ° ≦ arg (Z) ≦ 40 °.
As a result, the current reduction effect of the inductor is reduced without performing the phase-advancing switching, and the voltage VDC of the DC power supply and the lamp voltage VL during the steady operation of the fluorescent lamp are 1.2 VL ≦.
By setting the relationship of VDC ≦ 2.0 VL, the withstand voltage and the capacity of the inductor of the resonant load circuit and the switching element of the inverter circuit are reduced and the power loss is reduced.

[0004]

However, the configuration described in Japanese Patent Laid-Open No. 10-243661 has a problem that sufficient control stability cannot be obtained, that is, a sufficient phase margin cannot be ensured. ing.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a discharge lamp lighting device and a lighting device in which the control operation is stable and the power loss is reduced.

[0006]

A discharge lamp lighting device according to claim 1, and a boost chopper circuit; a pair of switching devices connected in series with each other, a resonance load circuit of an inductor and a capacitor to which the discharge lamp is connected. And an inverter circuit for converting the DC voltage from the boost chopper circuit into a high frequency voltage and supplying it to the discharge lamp based on the switching of the switching device; the output of the boost chopper circuit so as to make the lamp current of the discharge lamp constant. An integrator having an error amplifier for controlling the voltage is provided, and a control means is provided in which the lowest pole frequency of the integrator is set higher than the lowest pole frequency of the entire open loop transfer function. Then, the overall response in the low frequency range is determined by the boost chopper circuit, and the transfer function of the boost chopper circuit becomes a linear system in the critical mode of this chopper circuit, but the lowest pole frequency of the integrator and the overall response. When the lowest pole frequency of the open loop transfer function approaches, it becomes a quadratic system, and the response near the lowest pole frequency of the overall open loop transfer function becomes close to the second order lag, and the direction around the phase increases and the operation becomes unstable. Becomes However, in the control means, the lowest pole frequency of the integrator is set higher than the lowest pole frequency of the entire open-loop transfer function, so the response near the lowest pole frequency of the overall open-loop transfer function becomes a first-order lag and the phase The area around becomes smaller and the operation becomes stable.

The discharge lamp lighting device according to a second aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the lowest pole frequency of the entire open loop transfer function is 20 Hz or less, and the influence of the ripple of the power supply frequency. To reduce the harmonics of the input current.

A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the first or second aspect, wherein the resonant load circuit has a resistance represented by a value obtained by dividing the lamp current IL by the lamp voltage VL. When this resonant load circuit is driven by a high frequency power source with a pure sine wave voltage Vac, 0.7VL≤
Vac ≦ VL, and the argument arg (Z) of the impedance of the resonant load circuit seen from the high frequency power supply is 0 ° <arg
The values of the inductor and the capacitor are set so that (Z) ≦ 40 °, and the argument arg (Z) is 0.
Since ° <arg (Z), it is possible to prevent the switching device from advancing to a phase, and arg (Z) ≤ 40 ° and 0.7V.
Since L ≦ Vac ≦ VL, the loss of the inductor and the switching loss of the resonant load circuit are reduced and the power loss is reduced.

According to a fourth aspect of the present invention, there is provided the discharge lamp lighting device according to the third aspect, wherein the impedance deviation angle arg (Z) of the inductor and the capacitor is such that arg (Z) ≦ 20 °. Since the value is set, the inductor loss and switching loss of the resonant load circuit are smaller and the power loss is smaller.

A discharge lamp lighting device according to claim 5 has a step-up chopper circuit; a pair of switching devices connected in series with each other, a resonance load circuit of an inductor and a capacitor to which the discharge lamp is connected, and a switching device. An inverter circuit that converts the DC voltage from the boost chopper circuit into a high-frequency voltage and supplies it to the discharge lamp based on the switching of the output voltage of the boost chopper circuit so that the lamp current of the discharge lamp is constant when the discharge lamp is lit. The output voltage of the step-up chopper circuit is controlled to be constant at no load and at light load before starting the discharge lamp, and when the discharge lamp is lit and at no load and at light load before starting the discharge lamp. Control means with different DC gains are provided, which can be used when the discharge lamp is lit and when there is no load before starting and when there is a light load. Each can be properly controlled.

A discharge lamp lighting device according to a sixth aspect of the present invention is the discharge lamp lighting device according to the fifth aspect, wherein the control means has a direct current gain when the discharge lamp is lit, at no load before starting the discharge lamp and at a light load. It is smaller than the time, and it is possible to use a switching device, an inductor and a capacitor having a low withstand voltage by suppressing a rise in the voltage of the boost chopper circuit at the time of no load and light load before starting.

An illumination device according to a seventh aspect is provided with the discharge lamp lighting device according to any one of the first to sixth aspects; a discharge lamp which is turned on by the discharge lamp lighting device; and a discharge lamp lighting device and a discharge lamp. And a device main body for performing each operation.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a lighting device of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing the external appearance of the lighting device.
Is a lighting device, and the lighting device 1 has a fixture body 2, a reflecting surface 3 is formed on the lower surface of the fixture body 2, and lamp sockets 4, 4 are attached to both ends of the reflecting surface 3 in the longitudinal direction. A fluorescent lamp FL as a discharge lamp is mounted between the lamp sockets 4 and 4. Also, FIG.
FIG. 3 is a circuit diagram showing a discharge lamp lighting device, and a part or all of the discharge lamp lighting device 5 shown in FIG. It should be noted that the discharge lamp lighting device 5 includes the fixture body 2
It may be arranged outside.

As shown in FIG. 1, this discharge lamp lighting device 5 has a frequency of 50 Hz and an effective voltage of 100 V, for example.
Filter circuit 11 to block high frequency from commercial AC power supply e
Is connected, and the input terminal of the full-wave rectifier circuit 12 is connected to the filter circuit 11 to form a DC power supply device 13 that outputs a smoothed DC voltage.

A boost chopper circuit 14 acting as an active filter is connected to the DC power supply device 13. In this boost chopper circuit 14, an inductor L1 and a field effect transistor Q1 as a switching device are connected to the output terminal of the full-wave rectifier circuit 12, and a diode D1 and a smoothing capacitor C1 are connected in parallel to the field effect transistor Q1. A series circuit is connected.

Further, an inverter circuit 15 is connected to the boost chopper circuit 14. This inverter circuit
A field effect transistor Q2, Q3 as a pair of switching devices is connected in series to the unit 15. A drive circuit (not shown) is connected to the gates of the field effect transistors Q2 and Q3, and the field effect transistor Q2 and the field effect transistor Q3 are alternately arranged at a constant frequency during operation.
Turn on and off.

Further, the field effect transistor Q3 has one end of each filament FL1, FL2 of the fluorescent lamp FL via a series circuit of a capacitor C2 for cutting a direct current and an inductor L2 which also functions as a current limiting element in a winding part. And a so-called capacitor preheating capacitor C3 is connected between the other ends of the filaments FL1 and FL2 to form a resonance load circuit 16 which is an LC resonance circuit.

Further, there is provided a control circuit 21 as a control means which constitutes a feedback control system.
In the filament FL2 side, a lamp current detection coil 22 is wound around both the one terminal and the other terminal of the filament FL2 so as to cut a direct current component, and the lamp current detection coil 22 is connected to a lamp current detection circuit 23. ing. Further, the lamp current detection circuit 23 is connected to the error amplifier via the resistor R3.
It is connected to the inverting input terminal of 24, and the reference voltage source E1 is connected to the non-inverting input terminal of this error amplifier 24. In addition,
The voltage value of the reference voltage source E1 is set in accordance with the voltage from the lamp current detection circuit 23 in which the current value of the fluorescent lamp FL corresponds to the rated current during lighting. Further, a parallel circuit of a capacitor C4 and a resistor R4 is connected between the inverting input terminal and the output terminal of the error amplifier 24 to form an integrator 25, and the output terminal of the error amplifier 24 is connected to the multiplier 26. Further, the multiplier 26 is a resistor R5 and a resistor for detecting the power supply voltage connected between the positive output terminal of the full-wave rectifier circuit 12 and the ground.
The multiplier 26 is connected to the connection point of the resistor R5 and the resistor R6 in the series circuit of R6, and the multiplier 26 multiplies the power supply voltage by the current value of the fluorescent lamp FL to control the frequency and the duty ratio. It is connected to the gate of the effect transistor Q1.

Further, when the resonance load circuit 16 is driven by a high frequency power source having a pure sine wave voltage Vac and the lamp current of the fluorescent lamp FL is set to IL, 0.7VL≤Vac≤.
By setting to VL, the power loss is reduced.

Further, the deflection angle arg (Z) of the impedance of the resonance load circuit 16 is set to 0 ° <arg (Z) ≦ 40 °, preferably arg (Z) ≦ 20 °. Here, when the resistance value obtained by dividing the lamp current IL by the lamp voltage VL with the fluorescent lamp FL as the resistance is R, the inductance value of the inductor L2 is L, and the capacitance value of the capacitor C3 is C, an inverter circuit which is a high frequency power source The impedance when the resonant load circuit 16 was viewed from the 15 side was Z, and the power loss of the inductor L2 when the argument angle arg (Z) of the impedance of the resonant load circuit 16 was changed was calculated. At this time, C ² is sufficiently large and 1 / ωC ² can be ignored. The deflection angle arg (Z) of the impedance of the resonance load circuit 16 is as shown in FIG. 3, and the impedance Z of the resonance load circuit 16 is Z = jωL + {1 / (1 / R + jωC)} = ZR + j (XL- XC).

Further, ZR = R / (1 + ω²C²R²), XL
= ΩL, XC = 1 / {ω (1 + ω²C ²R²) / Ω²C
R²}}.

When the high frequency power supply voltage is constant, the smaller the deviation angle arg (Z) of the impedance Z of the resonance load circuit 16, the smaller the power loss of the inductor L2, and the deviation angle arg.
The power loss is minimum when (Z) = 0 °. The loss of the inductor L2 is K1 (constant) × current value × current value × ω
Although determined by L, the L value relatively increases as the argument arg (Z) increases. Note that the argument arg (Z) <
When the angle becomes 0 °, the L value becomes smaller, but it is not preferable because the field effect transistors Q2 and Q3 are in the phase advance switching mode.

Similarly, when considering the field effect transistors Q2 and Q3 when the deflection angle arg (Z) of the impedance Z of the resonance load circuit 16 is considered, these field effect transistors Q2 and Q3 are also biased to the resonance load circuit 16. The smaller the angle arg (Z), the smaller the switching loss.
It shows that the power loss is minimum when (Z) = 0 °. That is, the phase difference between the current and voltage of the switching device becomes 0 as the argument arg (Z) = 0 ° is approached.
, And thus the switching losses are reduced.

The pole frequency of the transfer function of the integrator 25 is set by the capacitor C4 and the resistor R4.

Further, the lowest pole frequency of the integrator 25 of the control circuit 21 is set higher than the lowest pole frequency of the entire open loop transfer function of the discharge lamp lighting device 5, and in the vicinity of the lowest pole frequency of the open loop transfer function. The response of is set as a first-order lag, and the direction around the phase is reduced to increase the phase margin to stabilize the operation. If the lowest pole frequency of the integrator 25 of the control circuit 21 and the lowest pole frequency of the entire open loop transfer function of the discharge lamp lighting device 5 are near frequencies,
The response in the vicinity of the lowest pole frequency of the open-loop transfer function becomes a second-order lag, the direction around the phase becomes large, the phase margin becomes small, and the operation becomes unstable.

Further, by setting the lowest pole frequency of the entire discharge lamp lighting device 5 to 20 Hz or less, it is possible to reduce the influence of ripples when the commercial AC power source e has a power source frequency of 50 Hz.

Next, the operation of the above embodiment will be described.

First, high frequency is blocked by the filter circuit 11 from the voltage of the commercial AC power source e, full-wave rectified by the full-wave rectifier circuit 12, and the field effect transistor Q1 of the boost chopper circuit 14 is controlled by the drive circuit 27 to boost the voltage. Then, the capacitor C1 is charged. Since the inductor L1 operates in the critical mode, the boost chopper circuit 14 operates as an active filter, and when the boost chopper circuit 14 operates as an active filter, the transfer function of the boost chopper circuit 14 becomes linear.

Then, the control device (not shown) alternately turns on the field effect transistors Q2 and Q3 at a constant frequency,
Turn it off, and the voltage charged in this capacitor C1
A high frequency voltage is supplied to the fluorescent lamp FL to turn on the fluorescent lamp FL.

The lamp current detection coil 22 detects the lamp current of the fluorescent lamp FL, the lamp current detection circuit 23 detects the lamp current, the error amplifier 24 of the integrator 25 performs error amplification, and the output is multiplied. Multiply by device 26 and drive circuit 27
The driving circuit 27 controls the switching of the field effect transistor Q1 to change the output voltage of the step-up chopper circuit 14 to control the lamp current of the fluorescent lamp FL during lighting to be constant. That is, when the rated lamp current is flowing when the fluorescent lamp FL is turned on, the output voltage from the lamp current detection circuit 23 and the voltage value of the reference voltage source E1 are equal, and therefore the integrator 25 does not change the output. The output of drive circuit 27 is not changed, but if the lamp current is large, an integrator
25 controls the output voltage of the boost chopper circuit 14 to be small, and in the opposite case, the integrator 25 controls the boost chopper circuit 14
The output voltage of is controlled to be large. Also, the resistance R5
Also, the power supply voltage detected by the resistor R6 is multiplied by the lamp current, and the output voltage of the boost chopper circuit 14 is controlled even in response to the power supply voltage. In this way, the lamp current of the fluorescent lamp FL is made constant by controlling the output voltage of the step-up chopper circuit 14, so that the deflection angle arg (Z) of the impedance Z of the resonant load circuit 16 is reduced and the reactance of the inductor L2 is reduced. Even if the current limiting action is reduced by reducing the value to reduce the size of the winding, the current of the fluorescent lamp FL can be controlled to be constant.

Here, a description will be given of a Bode diagram in which the open circuit transfer function is measured by a frequency characteristic analyzer (model number FRA5090 manufactured by NF Circuit Design Block Co., Ltd.).

In FIG. 4, the lowest pole frequency of the open loop transfer function is 4 Hz, and the lowest pole frequency of the integrator 25 is 70.
FIG. 5 is a gain characteristic diagram when the frequency is 0 Hz, and FIG. 5 is a phase characteristic diagram when the lowest pole frequency of the open loop transfer function is 4 Hz and the lowest pole frequency of the integrator 25 is 700 Hz. On the other hand, in FIG. 6, the lowest pole frequency of the open loop transfer function is 4 Hz, and the lowest pole frequency of the integrator 25 is 1.
FIG. 7 is a gain characteristic diagram with 5 Hz, and FIG. 7 is a phase characteristic diagram with the lowest pole frequency of the open loop transfer function being 4 Hz and the lowest pole frequency of the integrator 25 being 15 Hz.

When the lowest pole frequency of the open loop transfer function shown in FIG. 4 is 4 Hz and the lowest pole frequency of the integrator 25 is 700 Hz, the gain characteristic is attenuated by -20 dB / dec near the gain of 0 dB. In contrast to the first-order system, the gain characteristic of a loop transfer function shown in FIG. 6 in which the lowest pole frequency is 4 Hz and the lowest pole frequency of the integrator 25 is 15 Hz is −
It can be seen that this is a second-order system that attenuates at 40 dB / dec.

Considering the phase margin, the lowest pole frequency of the open loop transfer function shown in FIGS. 4 and 5 is 4 Hz, and the lowest pole frequency of the integrator 25 is 700H.
The value z is larger and more stable than the one in which the lowest pole frequency of the open loop transfer function shown in FIGS. 6 and 7 is 4 Hz and the lowest pole frequency of the integrator 25 is 15 Hz. That is, the stability is increased by setting the lowest pole frequency of the integrator 25 sufficiently high with respect to the lowest pole frequency of the open loop transfer function.

In FIGS. 4 to 7, the characteristics are unstable near 50 Hz to 100 Hz at 50 Hz and 10 Hz.
This is due to the ripple of the power supply frequency of 0 Hz, and it is considered that this was caused by the frequency characteristic analyzer not being able to separate them completely.

Next, a description will be given of what is represented as a Bode diagram by measuring the open loop transfer function with different capacitances of the capacitor C1.

FIG. 8 is a gain and phase characteristic diagram in which the capacitance of the capacitor C1 is 22 μF, the lowest pole frequency of the open loop transfer function is 22 Hz, and the lowest pole frequency of the integrator 25 is 700 Hz. FIG. With the capacitance of 47 μF and the lowest pole frequency of the open loop transfer function set to 18 Hz and the lowest pole frequency of the integrator 25 set to 700 Hz, the gain and phase characteristics are shown in FIG. FIG. 7 is a gain and phase characteristic diagram when the low pole frequency is 4 Hz and the lowest pole frequency of the integrator 25 is 700 Hz.

When the lowest pole frequency of the open loop transfer function shown in FIG. 8 is 22 Hz, the fluorescent lamp FL can be turned on, but the phase margin is not sufficient and flicker occurs, and the open loop transfer function shown in FIG. Low pole frequency is 18H
In the case of z, a phase margin of 80 deg is secured and the fluorescent lamp FL is lit stably, and in the case of the lowest pole frequency of the loop transfer function shown in FIG.
The fluorescent lamp FL is stably lit with 0 deg secured.

As described above, the phase margin is increased and the stability is increased by setting the capacitance of the capacitor C1 to a large value so that the lowest pole frequency of the open loop transfer function is 20 Hz or less.

Next, a discharge lamp lighting device according to another embodiment will be described with reference to FIG.

FIG. 11 is a circuit diagram showing a discharge lamp lighting device of another embodiment. The discharge lamp lighting device 5 of the embodiment shown in FIG. 11 is the same as the discharge lamp lighting device 5 shown in FIG.
Instead of the resistor R3 connected to the lamp current detection circuit 23, the voltage is divided by a series circuit of resistors R11 and R12,
Capacitor in parallel with series circuit of R11 and resistor R12
C11 is connected to the inverting input terminal of the error amplifier 24 via the diode D11 from the connection point of the resistors R11 and R12, and the inverting input terminal is grounded via the resistor R13. In addition, the voltage dividing resistor R1 is connected in parallel with the capacitor C1.
A series circuit of 4 and a resistor R15 is connected, and the connection point of these resistors R14 and R15 is connected to the inverting input terminal of the error amplifier 24 via the diode D12. The diode D11 and the diode D12 form a high value priority circuit 31. In addition, the relationship between the resistance values of the resistors R11 and R12 and the resistance values of the resistors R14 and R15 is such that the voltages of the resistors R11 and R12 are preferentially input to a high value after the fluorescent lamp FL is turned on. Set the resistance values of R11, resistor R12, resistor R14, and resistor R15. Furthermore, the resistance
By making the resistance values of R11 and R12 relatively large with respect to the resistance values of R14 and R15, before starting the fluorescent lamp FL, or when the fluorescent lamp FL is not installed and when there is no load and when there is a light load. In comparison, the DC gain in the control loop when the fluorescent lamp FL is lit is reduced.

Next, the operation of the above embodiment will be described.

The basic operation is the same as that shown in FIG. 1, but the lamp current of the fluorescent lamp FL is before the fluorescent lamp FL is started or when the fluorescent lamp FL is not mounted and when there is no load. Since it is not flowing, the lamp current detection circuit 23 does not output or has a small output.Therefore, the voltage of the capacitor C1 divided by the resistors R14 and R15, that is, the output voltage of the boost chopper circuit 14 is the diode D12. Is input to the integrator 25 via the booster chopper circuit 14 to control the field effect transistor Q1 of the booster chopper circuit 14 according to the output voltage of the booster chopper circuit 14,
Keep the output voltage of 14 constant.

On the other hand, when the fluorescent lamp FL is turned on, a lamp current flows through the fluorescent lamp FL, and the output from the lamp current detection circuit 23, which is divided by the resistors R11 and R12, is divided by the resistors R14 and R15. Since the voltage is set higher than the voltage, the output voltage of the boost chopper circuit 14 is controlled so that the lamp current flowing through the fluorescent lamp FL becomes constant.

Here, in the case of control based on the output voltage of the step-up chopper circuit 14 before the fluorescent lamp FL is started or when the fluorescent lamp FL is not mounted and under no load, the DC gain is fixed and the fluorescent lamp is fixed. A description will be given of what is represented as a Bode diagram by measuring the open circuit transfer function with different DC gains in the case of control based on the lamp current when the lamp FL is turned on.

FIG. 12 is a gain and phase characteristic diagram of the case where the DC gain in the control based on the lamp current when the fluorescent lamp FL is lit is increased, and FIG. 13 shows the control based on the lamp current when the fluorescent lamp FL is lit. FIG. 14 is a gain-and-phase characteristic diagram when the DC gain in the case is set to a medium level, and FIG. 14 is a gain-and-phase characteristic diagram when the DC gain is reduced in the case of control based on the lamp current when the fluorescent lamp FL is turned on.

It can be seen that the fluorescent lamp FL having a smaller DC gain shown in FIG. 14 has a larger phase margin than the one having a large DC gain shown in FIG. Lighting is stabilized by reducing the DC gain of.

Further, the DC gain in the case of control based on the output voltage of the step-up chopper circuit 14 before the fluorescent lamp FL is started or when the fluorescent lamp FL is not mounted and when there is no load and a light load is relatively increased. As a result, an increase in the output voltage of the boost chopper circuit 14 under no load or a light load can be suppressed, so that the capacitor C1 and the field effect transistors Q2, Q3 having a low withstand voltage can be used.

[0050]

According to the discharge lamp lighting device of the first aspect of the present invention, since the lowest pole frequency of the integrator is set higher than the lowest pole frequency of the entire loop transfer function in the control means, the whole loop of the The response in the vicinity of the lowest pole frequency of the transfer function becomes a first-order lag, and the direction around the phase becomes smaller, so that the operation can be stabilized.

According to the discharge lamp lighting device of the second aspect,
In addition to the discharge lamp lighting device according to the first aspect, since the lowest pole frequency of the entire open loop transfer function is 20 Hz or less, the influence of the ripple of the power supply frequency can be reduced and the harmonics of the input current can be reduced.

According to the discharge lamp lighting device of the third aspect,
In addition to the discharge lamp lighting device according to claim 1 or 2, the resonance load circuit uses a discharge lamp, a lamp current IL, and a lamp voltage VL.
When the resonance load circuit is driven by a high frequency power source with a pure sine wave voltage Vac, it is 0.7V
L ≦ Vac ≦ VL, and the deflection angle arg (Z) of the impedance of the resonant load circuit seen from the high frequency power supply is 0 ° <arg.
Since the values of the inductor and the capacitor are set so that (Z) ≦ 40 °, the argument arg (Z) is 0 °.
<Arg (Z) prevents the switching device from advancing, and arg (Z) ≦ 40 ° and 0.7 VL
Since ≦ Vac ≦ VL, power loss can be reduced by reducing inductor loss and switching loss of the resonant load circuit.

According to the discharge lamp lighting device of the fourth aspect,
In addition to the discharge lamp lighting device according to claim 3, since the values of the inductor and the capacitor are set so that the argument arg (Z) of the impedance satisfies arg (Z) ≤ 20 °, the inductor of the resonant load circuit. And the switching loss are smaller, and the power loss can be smaller.

According to the discharge lamp lighting device of the fifth aspect,
Appropriate control can be performed when the discharge lamp is lit, when there is no load before starting, and when there is a light load.

According to the discharge lamp lighting device of the sixth aspect,
In addition to the discharge lamp lighting device according to the fifth aspect, it is possible to use a switching device, an inductor and a capacitor having a low breakdown voltage by suppressing a rise in the voltage of the boost chopper circuit at the time of no load and light load before starting.

According to the lighting device of the seventh aspect, since the discharge lamp lighting device according to any one of the first to sixth aspects and the fixture main body to which the discharge lamp is attached are provided, each effect can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a discharge lamp lighting device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the outer appearance of the above lighting device.

FIG. 3 is a graph showing an impedance deviation angle of the resonance load circuit of the same.

FIG. 4 is the same as above, where the lowest pole frequency of the open loop transfer function is 4
FIG. 6 is a gain characteristic diagram when the lowest pole frequency of the integrator is 700 Hz and is 700 Hz.

[FIG. 5] Same as above, where the lowest pole frequency of the open loop transfer function is 4
It is a phase characteristic figure of what was set to Hz and the lowest pole frequency of an integrator was set to 700 Hz.

FIG. 6 is the same as above, where the lowest pole frequency of the open loop transfer function is 4
It is a gain characteristic figure when Hz is set to 15 Hz and the lowest pole frequency of an integrator is set.

FIG. 7 is the same as above, where the lowest pole frequency of the open loop transfer function is 4
It is a phase characteristic figure of what was set to Hz and the lowest pole frequency of an integrator was set to 15 Hz.

FIG. 8 is a gain and phase characteristic diagram in which the capacitance of the capacitor C1 is 22 μF, the lowest pole frequency of the open loop transfer function is 22 Hz, and the lowest pole frequency of the integrator is 700 Hz.

FIG. 9 is a gain and phase characteristic diagram in which the capacitance of the capacitor C1 is 47 μF, the lowest pole frequency of the open loop transfer function is 18 Hz, and the lowest pole frequency of the integrator is 700 Hz.

FIG. 10 is a gain and phase characteristic diagram in which the capacitance of the capacitor C1 is 150 μF, the lowest pole frequency of the open loop transfer function is 4 Hz, and the lowest pole frequency of the integrator is 700 Hz.

FIG. 11 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the above.

FIG. 12 is a gain and phase characteristic diagram of a DC gain increased in the control based on the lamp current when the fluorescent lamp FL is turned on.

FIG. 13 is a gain and phase characteristic diagram in which the DC gain in the case of control based on the lamp current when the fluorescent lamp FL is turned on is set to a medium level.

FIG. 14 is a gain and phase characteristic diagram in which the DC gain is reduced in the case of control based on the lamp current when the fluorescent lamp FL is turned on.

[Explanation of symbols]

1 Lighting device 2 Fixture body 5 Discharge lamp lighting device 11 Filter circuit 14 Boost chopper circuit 15 Inverter circuit 16 Resonance load circuit 21 Control circuit as control means 24 Error amplifier 25 Integrator C3 Capacitor FL Fluorescent lamp as discharge lamp L2 Inductor Q2 , Q3 field effect transistor as switching device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiichi Shimizu             4-3-1, Higashishinagawa, Shinagawa-ku, Tokyo Toshiba             Inside Litec Co., Ltd. F term (reference) 3K072 AA02 AC02 AC11 BA05 BB10                       CA14 CB05 CB07 CB10 DA02                       DB03 DB09 DC07 DE02 EA02                       FA02 FA05 GA02 GB12 GC04                       HA04 HA05 HA10 HB03

Claims (7)

[Claims] 1. A boost chopper circuit; a pair of switching devices connected in series with each other, a resonance load circuit of an inductor and a capacitor to which a discharge lamp is connected, and a boost chopper circuit based on switching of the switching device. An inverter circuit for converting the DC voltage of the DC voltage into a high frequency voltage and supplying it to the discharge lamp; and an integrator having an error amplifier for controlling the output voltage of the step-up chopper circuit so as to make the lamp current of the discharge lamp constant, And a control means in which the lowest pole frequency of is higher than the lowest pole frequency of the entire open loop transfer function. 2. The lowest pole frequency of the entire open loop transfer function is 20 Hz or less.
The discharge lamp lighting device described. 3. The resonance load circuit is a discharge lamp having a resistance represented by a value obtained by dividing a lamp current IL by a lamp voltage VL,
When this resonant load circuit is driven by a high frequency power source with a pure sine wave voltage Vac, 0.7 VL ≤ Vac ≤ VL, and the deflection angle arg (Z) of the impedance of the resonant load circuit seen from the high frequency power source is 0 ° <.
The discharge lamp lighting device according to claim 1 or 2, wherein the values of the inductor and the capacitor are set so that arg (Z) ≤ 40 °. 4. The impedance argument arg (Z) is
The discharge lamp lighting device according to claim 3, wherein the values of the inductor and the capacitor are set so that arg (Z) ≦ 20 °. 5. A step-up chopper circuit; a pair of switching devices connected in series with each other, a resonance load circuit of an inductor and a capacitor to which a discharge lamp is connected, and a boost chopper circuit based on switching of the switching device. An inverter circuit that converts the DC voltage of the DC voltage into a high-frequency voltage and supplies it to the discharge lamp; the output voltage of the boost chopper circuit is controlled so that the lamp current of the discharge lamp is constant when the discharge lamp is lit, and before the discharge lamp is started. The output voltage of the step-up chopper circuit is controlled to be constant under no load and light load, and the DC gain is made different between when the discharge lamp is lit and when there is no load before starting the discharge lamp and when there is a light load. A discharge lamp lighting device comprising: 6. The discharge lamp lighting device according to claim 5, wherein the control means has a DC gain at lighting of the discharge lamp smaller than that at no load and at light load before starting the discharge lamp. 7. A discharge lamp lighting device according to any one of claims 1 to 6, a discharge lamp lit by the discharge lamp lighting device, and a fixture main body in which the discharge lamp lighting device and the discharge lamp are provided. A lighting device characterized by the above.