JPH0521185A - Inverter device - Google Patents

Abstract

PURPOSE:To suppress the generation of a pulsation component generated in an inverter device, and to obtain an inverter device with little circuit loss, by making the voltage at both ends of a capacitor to be a driving source of a control circuit which compose the inverter device, into a compound voltage having a slipped phases, in an inverter device which has a chopper circuit. CONSTITUTION:The second power source circuit 12 to compose an inverter device is made in a constitution different from the conventional circuit. That is, an inductor T for chopper is placed between an AC power source AC and a rectifier circuit 2, one end of the secondary winding n2 of the inductor T is connected to a capacitor C2 through a normal direction of diode D2, and the other end is connected to the earthing line of the circuit. In this case, the winding number of the winding n2 of the inductor T is converted to make the phase of the b voltage of the circuit 12 different 90 deg. to the phase of the a voltage of the first power source circuit 11. Furthermore, a winding 2 and a resistance R1 are set to make the wave height value of the b voltage and the wave height value of the a voltage equal, and the pulsation corresponding to the high-frequency wave number generated to the high-frequency output voltage is made smaller.

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 for lighting a discharge lamp.

[0002]

2. Description of the Related Art Conventionally, an inverter device that receives an AC voltage from an AC power source, rectifies it, smoothes it with a smoothing capacitor to obtain a DC voltage, converts this DC voltage into an AC voltage, and supplies it to a load is often used. There is. In such a device,
Since the input current flows only for a part of the half cycle of the AC voltage, the waveform is extremely distorted. Therefore, the input power factor also decreases. Recently, an increase in the number of devices that supply a distorted input current causes a problem that the AC voltage waveform of an AC power source is distorted and adversely affects other devices. Therefore, instead of using only the smoothing capacitor on the input side of the inverter circuit, a structure in which a chopper circuit is added is often used.

FIG. 3 shows an example of such an inverter device, which has an AC power supply AC, a rectifier circuit 2 connected to both ends of the AC power supply AC and outputting a DC voltage, and A chopper circuit 3 that receives a DC output voltage of the rectifier circuit 2 and intermittently outputs a DC voltage, and a smoothing capacitor C1 that smoothes the output voltage of the chopper circuit 3.
An inverter circuit 4 connected to both ends of the smoothing capacitor C1, a first power supply circuit section 11 obtained by rectifying an AC voltage of an AC power supply AC, and an AC power supply voltage obtained from a chopper circuit 3 are obtained by rectification. The second power supply circuit section 12, the capacitor C2 connected to the output terminals of the first and second power supply circuit sections 11.12, and the chopper circuit 3 and the inverter circuit 4 using the voltage of the capacitor C2 as a drive voltage. And a control circuit 5 for on / off controlling the switching elements S1, S2, S3 included in the above.

Here, the chopper circuit 3 comprises a series circuit of a chopper inductor L and a chopper switching element S3 connected to both ends of the rectifier circuit 2, and a forward diode for supplying an output voltage to the smoothing capacitor C1. D3
It consists of and. Further, the inverter circuit 4 is configured to include switching elements S1, S2, etc., and converts a DC voltage into a high frequency voltage. The first power supply circuit section 11 is composed of a resistor R1 connected to one end of the AC power supply AC and a forward diode D1, and the second power supply circuit section 12 is
A secondary winding provided in the chopper inductor L,
A diode D2 is connected to one end of the secondary winding, and the cathode side of each diode D1 and D2 is connected to supply a DC voltage to the capacitor C2. The negative terminal of the capacitor C2 is connected to the negative side of the rectifier circuit 2 (hereinafter referred to as the circuit ground point), and the other end of the secondary winding provided in the chopper inductor L is also connected to the circuit ground. Connected to a point.

The operation state will be described below with reference to FIGS. 4 and 5. First, a pulsating DC voltage is generated at the output terminal of the rectifier circuit 2 by receiving the AC voltage of the AC power supply AC. When the chopper switching element S3 is turned on, the output terminal of the rectifier circuit 2 is short-circuited via the chopper inductor L, and the pulsating direct current voltage is used as a power source for the chopper inductor L.
Current flows through. Next, when the chopper switching S3 is turned off, the energy stored in the chopper inductor L is discharged to the smoothing capacitor C1 via the forward diode D3 and charges the smoothing capacitor C1. The DC voltage of the smoothing capacitor C1 becomes the DC input voltage of the inverter circuit 4, the switching elements S1 and S2 included in the inverter circuit 4 are alternately turned on and off, and the discharge lamp which is a load connected to the output terminal thereof. A high frequency voltage is supplied to (not shown). Each of the switching elements S1, S2, S3 is driven by an output signal of a control circuit 5 which is generally composed of an integrated circuit IC or the like. The power source of the control circuit 5 is the voltage across the capacitor C2. The capacitor C2 includes a first power supply circuit section 11 that receives the voltage of the AC power supply AC (a voltage waveform shown in FIG. 4) and a secondary winding n of the chopper inductor L.
It is charged by a voltage obtained by synthesizing the output of the second power supply circuit section 12 using the voltage (voltage waveform b shown in FIG. 4) generated at both ends of the second terminal.

When an integrated circuit such as an IC is used as the control circuit 5, a voltage (threshold voltage) at which the operation can be started.
Voltage supply), unstable operation tends to occur. Therefore, as shown in FIG.
The faster the voltage across both terminals rises, the better. Therefore, the time constants of the resistor R1 and the capacitor C2 cannot be made too large. As an example, when the AC power supply AC is 200 V, the resistance R1 is about 10 KΩ to 20 KΩ and the capacitor C2 is about several tens of micro F.

[0007]

With the above construction, the voltage of the capacitor C2 is generated like the potential c shown in FIG. The voltage generated at both ends includes a relatively large ripple voltage. This is because, as described above, it is necessary to rapidly increase the voltage across the capacitor C2 to prevent the control circuit 5 from operating in an unstable state. This is because the constant cannot be set too large. Therefore, for example, when the inverter circuit 4 is controlled by using a monostable multivibrator or the like as the control operation of the control circuit 5, the voltage of the capacitor C2 largely fluctuates in the cycle of the commercial frequency, so that the oscillation frequency is increased. Changes, and the voltage applied to the discharge lamp, which is the load, also fluctuates in the cycle of the commercial frequency, and is recognized as a fluctuation in the light output, which causes flicker.

Therefore, a configuration as shown in FIG. 6 can be considered. The difference from the configuration shown in FIG. 3 is that the power of the second power supply circuit section 12 is obtained from the other terminal of the AC power supply AC, which is different from the power receiving end of the first AC power supply AC.
With this structure, as shown in FIG. 7, the voltage generated across the capacitor C2 has a frequency twice the commercial frequency and a cycle of 1/2. Therefore, FIG.
The flicker feeling of the light source such as the discharge lamp is reduced as compared with the configuration shown in FIG. On the other hand, there is a problem that the loss due to the resistance R2 increases.

An object of the present invention is, in an inverter device having a chopper circuit, generation of a pulsating component corresponding to a commercial frequency generated in a high frequency output voltage of the inverter circuit can be suppressed as much as possible, and circuit loss can be suppressed. It is to provide a small number of inverter devices.

[0010]

SUMMARY OF THE INVENTION The present invention is a rectifier circuit connected to both ends of an AC power source to output a pulsating direct current voltage, a chopper circuit coupled to the output of this pulsating direct current voltage, and the output of this chopper circuit. A smoothing capacitor connected to the end, an inverter circuit connected to both ends of the smoothing capacitor to output a high frequency voltage, a capacitor connected from the input end of the AC power supply through at least a diode, and the voltage of this capacitor And a control circuit for ON / OFF controlling each of the switching elements included in the chopper circuit and the inverter circuit as a driving power source, and the chopper inductor of the chopper circuit is inserted between the AC power source and the rectifier circuit. The voltage generated between the secondary windings of the chopper inductor of at least the diode from the input end of the AC power supply. Those constituting at different voltage and approximately 90 ° phase obtained via.

[0011]

According to the present invention, since the chopper inductor of the chopper circuit is inserted between the AC power supply and the rectifier circuit, the pulsation component corresponding to the commercial frequency generated in the high frequency output voltage of the inverter circuit is generated. With such an effect, it is possible to provide an inverter device that can suppress the power consumption as much as possible and that has a small circuit loss.

[0012]

1 is a circuit configuration diagram showing a first embodiment of the present invention. A configuration different from that of FIG. 6 showing the above-mentioned conventional example is a second power supply circuit section 12. It inserts a chopper inductor T between an AC power supply AC and a rectifier circuit 2, connects one end of a secondary winding n2 of the chopper inductor T to a capacitor C2 via a forward diode D2,
The other end is connected to the circuit ground point. here,
The secondary winding n2 of the chopper inductor T is wound so that the phase of the voltage b of the second power supply circuit section 12 differs from the phase of the voltage a of the first power supply circuit section 90 by 90 °. Further, the secondary winding n2 of the chopper inductor T and the resistor R1 are set so that the peak value of the voltage b of the second power supply circuit section 12 and the peak value of the voltage a of the first power supply circuit section 11 are substantially equal to each other.
And are set. It should be noted that the same components are denoted by the same reference numerals and redundant description will be omitted.

With such a configuration, c in FIG.
As shown in the voltage, the voltage across the capacitor C2, which is the driving power source of the control circuit 5, is a voltage obtained by synthesizing the voltages of the respective power source circuit sections 11 and 12 by shifting the phases by 90 °, so that there is little pulsating direct current. As a result, it is possible to provide an inverter device in which the generation of a pulsating component corresponding to the commercial frequency generated in the high frequency output voltage of the inverter circuit 4 can be suppressed as much as possible and the circuit loss is small.

[0014]

According to the present invention, a rectifier circuit connected to both ends of an AC power source to output a pulsating current DC voltage, a chopper circuit coupled to the output of this pulsating current DC voltage, and connected to the output end of this chopper circuit. Smoothing capacitor, an inverter circuit connected to both ends of the smoothing capacitor to output a high frequency voltage, a capacitor connected from the input end of the AC power supply through at least a diode, and the voltage of this capacitor as a driving power supply. A chopper circuit and a control circuit for controlling on / off of each switching element included in the inverter circuit, and inserting the chopper inductor of the chopper circuit between an AC power supply and a rectifier circuit to form a chopper inductor of the chopper circuit. The voltage generated between the secondary windings of the AC power supply is obtained from at least the input terminal of the AC power supply through the diode. Since the phases are different by about 90 ° from each other, it is possible to suppress the occurrence of a pulsating component corresponding to the commercial frequency generated in the high frequency output voltage of the inverter circuit as much as possible, and to make an inverter device with less circuit loss. It has a great effect.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a waveform of each part for explaining an embodiment of the present invention.

FIG. 3 is a circuit configuration diagram showing a conventional example of the present invention.

FIG. 4 is an explanatory diagram showing waveforms of various parts for explaining a conventional example of the present invention.

FIG. 5 is an explanatory diagram for explaining a conventional example of the present invention.

FIG. 6 is a circuit configuration diagram showing another conventional example of the present invention.

FIG. 7 is an explanatory diagram showing waveforms of various parts for explaining another conventional example of the present invention.

[Description of symbols] AC AC power supply C1 Smoothing capacitor S1, S2, S3 Switching element T Chopper inductor for chopper circuit 2 Rectifier circuit 3 Chopper circuit 4 Inverter circuit 5 Control circuit

Claims (1)

Claim: What is claimed is: 1. An AC power supply, a rectifier circuit connected to both ends of the AC power supply to output a pulsating DC voltage, a chopper circuit coupled to the output of the pulsating DC voltage, and the chopper. A smoothing capacitor connected to the output end of the circuit; an inverter circuit connected to both ends of the smoothing capacitor to output a high frequency voltage; and a capacitor connected from the input end of the AC power supply through at least a diode, In an inverter device comprising a control circuit for performing on / off control of each switching element included in the chopper circuit and the inverter circuit using a voltage of a capacitor as a driving power source,
The chopper inductor of the chopper circuit is inserted between the AC power supply and the rectifier circuit, and the voltage generated between the secondary windings of the chopper inductor of the chopper circuit is passed through at least the diode from the input end of the AC power supply. An inverter device characterized in that it is configured so that the obtained voltage is different in phase by approximately 90 °.