JP3733675B2 - Inverter device, discharge lamp lighting device and lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inverter device, a discharge lamp lighting device, and a lighting device.
[0002]
[Prior 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 rectifier circuit 2 for full-wave rectification is connected to a commercial AC power supply 1 with a low frequency of 50/60 Hz, and a smoothing capacitor C ₀ by an electrolytic capacitor is connected between the DC power supplies that are full-wave rectified by the rectifier circuit 2. Are connected, and the smoothed voltage obtained across the smoothing capacitor C ₀ is applied as a power source for the subsequent inverter circuit 3.
[0003]
Here, the inverter circuit 3 is mainly composed of one switching element that is switched at a high frequency by a control circuit (not shown), for example, the transistor Q ₁ , and a backflow preventing diode is provided between the collector and emitter of the transistor Q _1. D ₁ is connected, and an LC voltage resonance circuit 4 including a capacitor C ₁ and a coil L ₁ is connected between the collector and one output terminal of the rectifier circuit 2. A fluorescent lamp 6 as a load is connected between both ends of the capacitor C _{1 in} the LC voltage resonance circuit 4 via an LC series resonance circuit 5 of a coil L ₂ and a capacitor C ₂ .
[0004]
In this type of circuit, the 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 the diode D ₃ and the discharge path 8 for discharging the charges of the capacitor C ₃ for determining the charging direction of the capacitor C ₃ to slow charging period the transient voltage change to the capacitor C ₃ The resistor R ₃ is formed to be connected in series with the transistor Q ₁ and in parallel with the LC voltage resonance circuit 4.
[0005]
However, in the case of such a capacitor-input type circuit configuration, the input current flowing from the commercial AC power supply 1 side has a pause period, and its peak value increases, resulting in large harmonic distortion. Therefore, in order to reduce such harmonic distortion (input distortion), a composite circuit system in which the inverter device itself has an input distortion reduction function has been proposed.
[0006]
FIG. 4 is a circuit diagram showing a configuration of a composite circuit type inverter device and a discharge lamp lighting device. Portions having the same functions as those shown in FIG. 3 are denoted by the same reference numerals (the same applies to other drawings). Here, the smoothing portion for smoothing the rectified output of the rectifier circuit 2 is configured as a series circuit 9 of 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 , the voltage resonance type inverter circuit 3 mainly composed of the transistor Q ₁ , and the high frequency ripple voltage component superimposed on the rectified output of the rectifier circuit 2 based on the switching of the transistor Q ₁ are shown. A composite circuit 11 is configured by the input distortion reduction circuit 10 to be generated. The input distortion reducing circuit 10 includes a coil L ₁ , a capacitor C ₄ connected between the collector and emitter of the transistor Q ₁ , and a capacitor C ₅ connected between the output terminals of the rectifier circuit 2 and before the series circuit 9. It is configured. In other words, the switching of the transistor Q ₁ for performing the inverter operation is essentially used to resonate the capacitor C ₅ in synchronism with the inverter circuit 3 to generate a high-frequency ripple voltage component.
[0007]
Here, the output voltage waveform of the commercial AC power supply 1 has a sinusoidal shape as is well known, and the output voltage waveform of the rectifier circuit 2 that performs full-wave rectification of the output voltage waveform of the commercial AC power supply 1 is in a pulsating state after full-wave rectification as is well known. DC voltage waveform. The inverter circuit 3 basically operates by being supplied with the output voltage of the rectifier circuit 2 and generates a high frequency voltage of several tens of kHz, for example. In the peak period where the instantaneous value (peak value) is higher than a predetermined value and the transistor Q ₁ is on, the positive output terminal of the rectifier circuit 2 → the inductor L ₁ → the collector / emitter of the transistor Q ₁ → rectification A current flows through the path of the negative output terminal of the 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, the voltage across the series circuit 9 is higher than the instantaneous value of the output voltage from the rectifier circuit 2). A voltage is supplied to the inverter circuit 3 from the smoothing capacitor C ₂ through the inductor L ₁ → the collector-emitter path of the transistor Q ₁ . Such a superposition action that makes the voltage across the series circuit 9 higher than the instantaneous value of the output voltage from the rectifier circuit 2 is the coil L ₁ , the capacitor C _4, and the capacitor C ₅ when the transistor Q ₁ is turned off in the switching operation. The capacitor C ₅ operates so as to resonate with the input distortion reduction circuit 10 by generating a high-frequency ripple voltage component.
[0008]
Thus, since 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 of the inverter circuit 3 is a pulsating voltage that is just rectified. As in the case where is supplied, the envelope does not have a portion that once decreases to zero voltage. Therefore, the input power factor is remarkably improved as compared with a so-called capacitor input type in which a smoothing capacitor C ₀ is simply provided between the output terminals of the rectifier circuit 2.
[0009]
[Problems to be solved by 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. 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 sometimes it takes for example 600V as high in the capacitor C _3. As a result, the capacitor C ₃ in the snubber circuit 7 must be used with a high withstand voltage. At the same time, the loss due to the resistor R ₃ for discharging the charge of the capacitor C ₃ is also increased.
[0010]
Accordingly, the present invention provides an inverter device, a discharge lamp lighting device, and an illumination device that can lower the withstand voltage of a capacitor in a snubber circuit and reduce loss due to a discharge path in a method using a composite circuit. With the goal.
[0011]
[Means for Solving the Problems]
An inverter device according to claim 1 is 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 that switches a DC voltage input from the series circuit side at a high frequency, a coil that is connected to the collector of the switching element and a capacitor that is connected in series with the switching element based on the switching of the switching element resonates. A composite circuit having a voltage resonance type inverter circuit for supplying a high frequency voltage to a load, and an input distortion reducing circuit for generating a high frequency ripple voltage component superimposed on a rectified output of the rectifier circuit based on switching of the switching element; A capacitor and a diode that determines the charging direction for the capacitor; And a discharge path having a resistance to discharge the charged electric charge of said capacitor, said capacitor is connected between the smoothing capacitor and the impedance element of the series circuit such that the series with said smoothing capacitor, And a snubber circuit in which the diode is connected between the collector of the switching element and a coil .
[0012]
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. A type transistor or the like can be used. Moreover, it becomes effective in the case of a single stone type because of the use of a snubber circuit. The inverter circuit in the composite circuit may be one stone type and a voltage resonance type, and the specific circuit configuration is not different. The input distortion reduction circuit may be configured to generate a high-frequency ripple voltage component to be superimposed by including a capacitor that resonates in synchronization with the inverter circuit by a switching element that is switched at a high frequency. An electrolytic capacitor is used as the smoothing capacitor in the series circuit connected between the output terminals of the rectifier circuit, and an inductance element such as a coil is typically used as the impedance element. The discharge path in the snubber circuit is for discharging the electric charge charged in the capacitor, and is usually formed by using a discharge resistor. This discharge resistor may be parallel to the capacitor or to the diode. .
[0013]
According to the present invention, the snubber circuit suppresses the peak value when the resonance state of the inverter circuit is changed for some reason and the voltage applied to the switching element changes greatly, but the peak value is reduced by the charging operation. Since the smoothing capacitor is connected in series with the capacitor for suppression, the voltage applied to the capacitor is 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 terms of circuit configuration. At the same time, loss due to the discharge path for discharging the charge of the capacitor can be reduced.
[0014]
A discharge lamp lighting device according to a second aspect of the invention includes the inverter device according to the first aspect; 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 lighting device including a snubber circuit having an advantageous configuration in which the withstand voltage of the capacitor may be low and loss due to the discharge path is small.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an inverter device and a discharge lamp lighting device according to the present invention will be described.
FIG. 1 is a circuit diagram showing an 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 in terms of components, but the connection point of the snubber circuit 7 is different, and the series circuit 9 Are 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 , the capacitor C ₃ is connected in series with the smoothing capacitor C ₀ .
[0016]
Next, the operation will be described. The transistor Q ₁ performs a switching operation at a high frequency 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 this to the fluorescent lamp 6 to turn on the fluorescent lamp 6. Maintain state. In such an inverter operation, when 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. This appears as a change in voltage at the connection point between D ₃ and the capacitor C ₃ . When the voltage at this point becomes larger than the normal collector-emitter voltage V _{CE, the} charging operation for the capacitor C ₃ is performed. As a result, a delay corresponding to the period required for the charging occurs, and as a result, the transistor Q ₁ The peak value is suppressed so that the voltage applied between the collector and the emitter of the transistor does not become larger than necessary. In the charging operation to such capacitor C _3, this since the capacitor C ₃ is in a state of being connected smoothing capacitor C ₀ in series, a capacitor C for smoothing a transient excessive voltage capacitor C _{3 0} It will take between 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, in the conventional example shown in FIG. 4, assuming that a high voltage of 600 V is applied to both ends of the capacitor C ₃ , according to the present embodiment, 200 V is divided into the smoothing capacitor C ₀ , The high voltage applied to the capacitor C ₃ in the snubber circuit 7 is suppressed to about 400V. In addition, the loss due to the discharge resistor R ₃ can be reduced as much as the withstand voltage of the capacitor C ₃ in the snubber circuit 7 may be lower and the charge voltage is lowered.
[0017]
FIG. 2 is a perspective view showing an embodiment of the illumination device of the present invention. In the figure, reference numeral 15 denotes a lighting fixture body, and a fluorescent lamp 6 as a discharge lamp is mounted on the lighting fixture body 15. In addition, a discharge lamp lighting device 13 including an inverter device 12 having the configuration described in FIG. But you may make it arrange | position the discharge lamp lighting device 13 out of the lighting fixture main body 15. FIG.
[0018]
【The invention's effect】
According to the first aspect of the present invention, in the inverter device provided with the composite circuit, the snubber circuit having a capacitor, a diode for determining a charging direction for the capacitor, and a discharge path for the capacitor is used as the smoothing capacitor. Since it is connected between the smoothing capacitor and the impedance element of the series circuit so as to be in series , and the diode is connected between the collector of the switching element and the coil , the snubber circuit When the transient high voltage peak value is suppressed by the capacitor charging operation, the high voltage can be divided by the smoothing capacitor to reduce the required breakdown voltage, and at the same time, the loss due to the discharge path is also reduced. An inverter device with a snubber circuit that can be reduced and has favorable conditions It can be provided.
[0019]
According to the second and third aspects of the present invention, since the inverter device according to the first aspect is provided, the capacitor with a low withstand voltage and a snubber circuit having an advantageous configuration with less loss due to the discharge path can be used. An electric lamp lighting device or a lighting device can be provided.
[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 an embodiment of an illumination device according to the present invention. FIG. 4 is a circuit diagram showing a configuration of an inverter device and a discharge lamp lighting device. FIG. 4 is a circuit diagram showing a configuration of a composite circuit type inverter device and a discharge lamp lighting device.
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)

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 the output terminals of the rectifier circuit;
One switching element that switches a DC voltage input from the series circuit side at a high frequency, a coil that is connected to the collector of the switching element based on switching of the switching element, and a capacitor that is connected in series to the coil are resonantly operated. And a voltage resonance type inverter circuit that supplies a high-frequency voltage to a load, and an input distortion reduction circuit that generates a high-frequency ripple voltage component that is superimposed on the rectified output of the rectifier circuit based on switching of the switching element. When;
A capacitor, a diode that determines a charging direction for the capacitor, and a discharge path that includes a resistor that discharges the charge of the capacitor, and the capacitor of the series circuit is connected in series with the smoothing capacitor . A snubber circuit connected between a smoothing capacitor and an impedance element , and wherein the diode is connected between a collector and a coil of the switching element ;
An inverter device comprising: An inverter device according to claim 1;
A discharge lamp as a load energized by the inverter circuit of the inverter device;
A discharge lamp lighting device comprising: A lighting fixture body;
A discharge lamp lighting device according to claim 2;
A discharge lamp provided in the lighting fixture main body and energized by the discharge lamp lighting device.

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