JPH10214689A - Inverter device, discharge lamp lighting device and lighting device - Google Patents

Abstract

(57) Abstract: In a method using a composite circuit, the breakdown voltage of a capacitor in a snubber circuit is reduced, and the loss due to a discharge path is reduced. SOLUTION: An inverter device 1 including a composite circuit 11 is provided.
In 2, a capacitor C _3, a diode D ₃ which determines the charging direction for the capacitor C _3, the snubber circuit 7 and a discharge path 8 for the capacitor C ₃ is a series that the capacitor C ₃ is a smoothing capacitor C ₀ by providing connecting so that, by dividing by the smoothing capacitor C ₀ that high pressure when attempting to suppress transient pressure peak value by the charging operation of the capacitor C ₃ of the snubber circuit 7, breakdown voltage required for the capacitor C ₃ has to move down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an inverter device,
The present invention relates to a discharge lamp lighting device and a lighting device.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram showing a configuration of a conventional general inverter device and discharge lamp lighting device. In this example, the power supply unit is configured as a capacitor input type. That is, a 50/60 Hz low frequency commercial AC power supply 1
A rectifier circuit 2 for full-wave rectification, a smoothing capacitor C ₀ by an electrolytic capacitor connected between the DC power supplies rectified by the rectifier circuit 2, and both ends of the smoothing capacitor C ₀ . The obtained smoothed voltage is configured to be supplied as a power source for the inverter circuit 3 thereafter.

[0003] Here, one switching element is an inverter circuit 3 are switched at a high frequency by a control circuit (not shown), for example, mainly formed of a transistor Q _1, the backflow prevention between the collector and emitter of the transistor Q ₁ diode D ₁ is connected in use, the capacitor C between the collector and the one output terminal of the rectifier circuit 2
LC voltage resonance circuit 4 by ₁ and the coil L ₁ is connected. Fluorescent lamp 6 is connected as a load via an LC series resonant circuit 5 of the coil L ₂ and capacitor C ₂ is across capacitor C ₁ of the LC voltage resonance circuit 4.

In this type of circuit, a snubber circuit 7 is added to suppress the peak value when the resonance state of the inverter circuit 3 changes and the voltage changes transiently.
The snubber circuit 7 diode D ₃ for determining the charging direction into the capacitor C ₃ and the capacitor C ₃ to slow charging period the transient voltage changes and the capacitor C ₃
Of which is constituted by a resistor R ₃ to form a discharge path 8 for discharging charges, they are connected in parallel series, with respect to LC voltage resonance circuit 4 for transistor Q _1.

However, in the case of such a capacitor-input type circuit configuration, the input current flowing from the commercial AC power supply 1 has a quiescent period and its peak value also increases, resulting in large harmonic distortion. I will. Therefore,
In order to reduce such harmonic distortion (input distortion), there has been proposed a composite circuit system in which the inverter device itself has an input distortion reduction function.

FIG. 4 is a circuit diagram showing a configuration of a composite circuit type inverter device and a discharge lamp lighting device. Parts performing the same functions as the parts shown in FIG. 3 are denoted by the same reference numerals (the same applies to other drawings). Here, a smoothing portion for smoothing the rectified output of the rectifier circuit 2 is configured as a series circuit 9 including a smoothing capacitor C ₀ by an electrolytic capacitor and an impedance element, for example, a coil L ₀ . In the illustrated example, the transistor Q ₁ and the transistor Q ₁
An inverter circuit 3 of the voltage resonance type consisting mainly of composite circuit 11 is constituted by an input distortion reduction circuit 10 for generating the ripple voltage component of the high-frequency superimposed on the rectified output of the rectifier circuit 2 on the basis of the switching of the transistor Q ₁ ing. Input distortion reducing circuit 10 is a coil L ₁ and the transistor Q
Capacitor C ₄ connected between collector and emitter of ₁
It is constituted by the capacitor C ₅ connected in the previous stage of the series circuit 9 a between the output terminals of the rectifier circuit 2 and. That, and generates the inherent ripple voltage component of the high frequency is resonant operation in synchronization with the inverter circuit 3 to the capacitor C ₅ using a switching transistor to Q ₁ for causing the inverter operation.

Here, the output voltage waveform of the commercial AC power supply 1 has a sine wave shape as is well known, and the output voltage waveform of the rectifier circuit 2 for full-wave rectification of the output voltage waveform is a well-known pulse waveform. It becomes a DC voltage waveform in a flowing state. Inverter circuit 3
Basically operates by being supplied with the output voltage of the rectifier circuit 2 and generating a high-frequency voltage of, for example, several tens of kHz. The instantaneous value of the output voltage from the rectifier circuit 2 ( During the ON period of the transistor Q ₁ , the positive output terminal of the rectifier circuit 2 → the inductor L ₁ → the collector of the transistor Q ₁ .
A current flows through a path from the emitter to the negative output terminal of the rectifier circuit 2. At the same time, current also flows to the serial circuit 9 by the output voltage from the rectifier circuit 2, a smoothing capacitor C ₀ is charged. On the other hand, when the instantaneous value of the output voltage from the rectifier circuit 2 is in a valley period lower than a predetermined value (that is, when the voltage across the series circuit 9 is higher than the instantaneous value of the output voltage from the rectifier circuit 2), The inverter circuit 3 has a smoothing capacitor C
_{From 2} inductor L ₁ → collector of transistor Q ₁
Voltage is supplied in the path of the emitter. Such a superimposing action that makes the voltage across the series circuit 9 higher than the instantaneous value of the output voltage from the rectifier circuit 2 causes the coil L ₁ , the capacitor C _4, and the capacitor C _{5 to be} turned off during the switching operation of the transistor Q _1. operating capacitor C ₅ to resonate with the input distortion reduction circuit 10 by carried out by generating a ripple voltage component of the high frequency.

As described above, the input voltage to the inverter circuit 3 is a pseudo-smoothed voltage in which the valley of the rectified waveform is filled with the high-frequency ripple voltage component.
The high frequency output has no portion which once drops to zero voltage in the envelope as in the case where only a rectified pulsating voltage is supplied. Therefore, as compared with merely a so-called capacitor input type provided with a smoothing capacitor C ₀ between the output ends of the rectifier circuit 2, greatly improved the input power factor.

[0009]

[SUMMARY OF THE INVENTION However, in the conventional snubber circuit 7 even in the inverter device provided with a composite circuit 11 is provided connected in parallel to the coil L ₁ as shown in FIG. 4 . Consequently, when you suppress the peak value by the snubber circuit 7 when the voltage across the transiently between transistors to Q ₁ collector-emitter resonance state of the inverter circuit 3 is changed for some reason it has changed surge voltage manner , for example 60 to the capacitor C ₃
A voltage as high as 0 V may be applied. As a result,
The capacitor C ₃ in the snubber circuit 7 not has to be used as a large breakdown voltage. At the same time, the loss is also increased due to the resistance R ₃ for discharging the electric charge of the capacitor C _3.

Accordingly, the present invention provides an inverter device, a discharge lamp lighting device, and a lighting device which can reduce the withstand voltage of the capacitor in the snubber circuit and reduce the loss due to the discharge path in a system using a composite circuit. The purpose is to provide.

[0011]

According to a first aspect of the present invention, there is provided an inverter apparatus for rectifying a low-frequency AC power supply voltage in full-wave, and a smoothing capacitor connected between output terminals of the rectifier circuit. A series circuit with an impedance element;
One switching element for switching a DC voltage inputted from the series circuit side at a high frequency, a voltage resonance type inverter circuit for performing a resonance operation based on the switching of the switching element and supplying a high frequency voltage to a load, and the switching element A composite circuit having an input distortion reduction circuit that generates a high-frequency ripple voltage component superimposed on the rectified output of the rectifier circuit based on the switching of the capacitor; a capacitor; a diode that determines a charging direction for the capacitor; and a discharge path for the capacitor. And a snubber circuit in which the capacitor is connected in series to the smoothing capacitor.

In the present invention, the switching element is used for both the inverter circuit and the input distortion reduction circuit in the composite circuit. However, the switching element itself may be any type, for example, a bipolar transistor. Or a field-effect transistor or the like. In addition, since a snubber circuit is used, this is effective in the case of a single stone type. The inverter circuit in the composite circuit only needs to be a single-pole type and a voltage resonance type, and the specific circuit configuration does not matter. The input distortion reduction circuit may be configured to generate a high-frequency ripple voltage component to be superimposed including a capacitor that resonates in synchronization with the inverter circuit by a switching element that switches at a high frequency.
An electrolytic capacitor is used as a smoothing capacitor in a series circuit connected between output terminals of the rectifier circuit, and an inductance element such as a coil is typically used as an impedance element. The discharge path in the snubber circuit is for discharging the electric charge charged in the capacitor, and is usually formed using a discharge resistor, but this discharge resistor may be in parallel with the capacitor or in parallel with the diode. .

According to the present invention, the peak value is suppressed by the snubber circuit when the resonance state of the inverter circuit changes for some reason and the voltage applied to the switching element greatly changes transiently. Since the smoothing capacitor is connected in series to the capacitor for suppressing the peak value, the voltage applied to the capacitor becomes a divided voltage, and the voltage applied to the smoothing capacitor can be reduced. Therefore, the withstand voltage required for the capacitor can be reduced, which is advantageous in the circuit configuration. At the same time, the loss due to the discharge path for discharging the charge of the capacitor can be reduced.

According to a second aspect of the present invention, there is provided a discharge lamp lighting device,
An inverter device according to claim 1, and a discharge lamp as a load energized by the inverter circuit of the inverter device. A lighting device according to a third aspect of the present invention includes a lighting fixture body; a discharge lamp lighting device according to claim 2; a discharge lamp provided in the lighting fixture body and energized by the discharge lamp lighting device; It has. Accordingly, it is possible to provide a discharge lamp lighting device or a lighting device provided with a snubber circuit having an advantageous configuration in which the withstand voltage of the capacitor may be low and the loss due to the discharge path is small.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an inverter device and a discharge lamp lighting device according to the present invention will be described below. FIG. 1 is a circuit diagram showing one embodiment. The inverter device 12 or the discharge lamp lighting device 13 according to the present embodiment is the same as that shown in FIG. 4 except for the connection point of the snubber circuit 7 and the series circuit 9. Is connected between a connection point between the coil L ₀ and the smoothing capacitor C ₀ and a connection point between the transistor Q ₁ and the coil L ₁ . Focusing on the capacitor C ₃ , this capacitor C ₃
It is connected such that the smoothing capacitor C ₀ in series.

Next, the operation will be described. The transistor Q ₁ performs a high-frequency switching operation based on a control signal from the control circuit, thereby generating a high-frequency voltage on the coil L ₁ side in the inverter circuit 3 and supplying the high-frequency voltage to the fluorescent lamp 6 to turn on the fluorescent lamp 6. Keep in state. During such an inverter operation, if the resonance state changes for some reason and the voltage V _CE applied between the collector and the emitter of the transistor Q ₁ changes transiently, the change in the voltage V _CE is caused by the diode in the snubber circuit 7. It appears as a change in the voltage at the connection point between D ₃ and capacitor C ₃ . When the voltage at this point becomes higher than the normal collector-emitter voltage V _{CE, the} charging operation for the capacitor C ₃ is performed, and a delay corresponding to the period required for the charging is caused. As a result, the transistor Q ₁ The peak value is suppressed so that the voltage applied between the collector and the emitter does not become unnecessarily large. In the charging operation to such capacitor C _3, since this is the capacitor C ₃ is in a state of being connected in series smoothing capacitor C _0, the capacitor C for smoothing a transient excessive voltage capacitor C ₃
It will be between ₀ and both ends. As a result of the voltage division, the voltage applied to the smoothing capacitor C ₀ is not applied to the capacitor C ₃ , so that the withstand voltage required for the capacitor C ₃ can be lower. Incidentally, assuming a case 600V as high across the capacitor C ₃ is applied as in the conventional example shown in FIG. 4, according to this embodiment, 200V fraction is divided into the smoothing capacitor C _0, The high voltage applied to the capacitor C ₃ in the snubber circuit 7 is 4
It is suppressed to about 00V. Also, the partial breakdown voltage of the capacitor C ₃ in the snubber circuit 7 may the charging voltage decreases at a lower, it is possible loss also reduced by the discharge resistor R _3.

FIG. 2 is a perspective view showing an embodiment of the lighting device of the present invention. In the figure, reference numeral 15 denotes a lighting fixture main body, on which a fluorescent lamp 6 as a discharge lamp is mounted. Further, a discharge lamp lighting device 13 including an inverter device 12 having the configuration described with reference to FIG. However, the discharge lamp lighting device 13 may be arranged outside the lighting fixture body 15.

[0018]

According to the invention, a snubber circuit having a capacitor, a diode for determining a charging direction for the capacitor, and a discharge path for the capacitor is provided in the inverter device including the composite circuit. Is connected in series to the smoothing capacitor, so if the transient high voltage peak value is to be suppressed by the charging operation of the capacitor in the snubber circuit, the high voltage is divided by the smoothing capacitor. The required withstand voltage can be reduced, and the loss due to the discharge path can be reduced at the same time, and an inverter device having a snubber circuit with advantageous conditions can be provided.

According to the second and third aspects of the present invention, since the inverter device according to the first aspect is provided, a snubber circuit having an advantageous configuration in which the withstand voltage of the capacitor may be low and the loss due to the discharge path is small. It is possible to provide a discharge lamp lighting device or a lighting device provided with the same.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing one embodiment of a lighting device of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a conventional general inverter device and a discharge lamp lighting device.

FIG. 4 is a circuit diagram showing a configuration of a combined circuit type inverter device and a discharge lamp lighting device.

[Explanation of symbols]

2: Rectifier circuit 3: Inverter circuit 6: Discharge lamp 7: Snubber circuit 8: Discharge path 9: Series circuit 10: Input distortion reduction circuit 11: Composite circuit 12: Inverter device 13: Discharge lamp lighting device 14: Lighting fixture body Q ₁ : Switching element C ₀ : Smoothing capacitor C ₃ : Capacitor L ₀ : Impedance element D ₃ : Diode

Claims (3)

[Claims] 1. A rectifier circuit for full-wave rectification of a low-frequency AC power supply voltage; a series circuit of a smoothing capacitor and an impedance element connected between output terminals of the rectifier circuit; One switching element for switching a DC voltage at a high frequency, a voltage resonance type inverter circuit for performing a resonance operation based on the switching of the switching element and supplying a high frequency voltage to a load, and the rectifying circuit based on the switching of the switching element. A composite circuit having an input distortion reduction circuit that generates a high-frequency ripple voltage component superimposed on the rectified output of the capacitor; a capacitor; a diode for determining a charging direction for the capacitor; and a discharge path for the capacitor. A snubber circuit in which a capacitor is connected in series with the smoothing capacitor. An inverter device characterized by the following. 2. A discharge lamp lighting device comprising: the inverter device according to claim 1; and a discharge lamp as a load energized by an inverter circuit of the inverter device. 3. A lighting device comprising: a lighting fixture main body; a discharge lamp lighting device according to claim 2; and a discharge lamp provided in the lighting fixture main body and energized by the discharge lamp lighting device. apparatus.