JPH1127947A - Power supply and method of controlling power supply voltage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply and a method for controlling the voltage of the power supply, wherein the power factor of an entire device mounted with a switching power supply is improved and distortion in input current can be reduced. SOLUTION: This power supply comprises a DC-DC converter circuit 10 which contains a switching transistor Q and converts commercial alternating currents into direct currents, a current transformer CT which is disposed so that lamp current detection signals from a lamp regulator 30 fed from the same power supply system is superposed in series with choke coil current detection signals applied to the current detection terminals on the control amplifier 22 of an active filter control circuit 20, and an active filter control circuit 20 which controls constant-voltage the switching transistor Q so that a combined value of the consumed current of the lamp regulator 30 and the consumed current of the DC-DC converter circuit 10 is turned into a sine wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device as an active filter type switching power supply and a voltage control method of the power supply device, and more particularly, to controlling a DC-DC converter circuit at a constant voltage by an active filter control circuit. The present invention relates to a power supply device and a voltage control method for the power supply device, which are suitable for suppressing the generation of harmonics and increasing the power factor.

[0002]

2. Description of the Related Art Conventionally, an active filter type switching power supply has a line consumption current of a sine wave in the same phase as an input voltage by appropriately controlling the on / off operation of a switching transistor of a DC-DC converter circuit, thereby greatly increasing a power factor. The power supply device has been improved. This method includes:
(1) The peak value of the input current decreases because the input current waveform becomes a sine waveform, (2) a wide input voltage range can be handled, (3) the load on the input line equipment of the device is reduced, (4) There are advantages that the waveform distortion is improved and various harmonic disturbances can be reduced, and (5) the converter circuit can be downsized because the input voltage is stable.

FIG. 9 is a circuit diagram showing an example of a typical active filter type switching power supply according to a conventional example.
The switching power supply mainly includes a step-up DC-DC converter circuit 10 and an active filter control circuit 20. In the switching power supply, the switching transistor Q of the DC-DC converter circuit 10 is turned on and off to control the line current consumption to be a sine wave having the same phase as the input voltage of the commercial power supply, thereby improving the power factor and fixing the output. Control the voltage.

The DC-DC converter circuit 10 includes a load 4
It comprises a switching transistor Q and a smoothing capacitor C arranged in parallel with 0, a choke coil L and a flywheel diode D arranged in series with the load 40, and the like. When the switching transistor Q is turned on, a current flows through the choke coil L and energy is stored. When the switching transistor Q is turned off, the energy stored in the choke coil L is released, passes through the flywheel diode D, and passes through the smoothing capacitor C. And supplied to the load 40. The output voltage Vo is determined by the on / off duty ratio of the switching transistor Q.

The active filter control circuit 20 has a DC
While comparing a voltage corresponding to the current iL flowing through the choke coil L of the DC converter circuit 10 with a target voltage proportional to the input voltage Vin,
Is turned on and off to shape the input current waveform into a sine wave in phase with the input voltage waveform. At this time, the output voltage is stabilized by adding the detection signal of the output voltage Vo to the target voltage to be compared. This type of circuit is already in the form of an IC and is commercially available (for example, “TDA4814” manufactured by Siemens), and can be configured by adding a few external components.

The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a comparator 26, and a status register 2.
8 and the like. The status register 28 stores N
AND gate 28a, RS flip-flop 28b, A
It comprises an ND gate 28c and an inverter 28d. The difference between the divided voltage Vf of the output voltage Vo by the voltage dividing resistors R1 and R2 and the reference voltage Vr is amplified by the control amplifier 22, and the control voltage V
The multiplier 24 calculates the product (target voltage) of s and the instantaneous value of the input voltage. Voltage drop of current sense resistor Rs of switching transistor Q (corresponding to instantaneous value of choke current)
Is compared with the target voltage from the multiplier 24 by the comparator 26, and the state register 28 is controlled.

The comparator 26 resets the status register 28 when the voltage drop of the current sense resistor Rs reaches the target voltage, and sets the status register 28 when the choke coil L has finished discharging. By this operation, the switching transistor Q repeatedly turns on and off, and FIG.
, The choke current iL becomes a triangular wave. The peak value corresponds to the target voltage by the multiplier 24, and the average input current iin becomes half of the choke current iL.
As a result, it is shaped into a sine wave in phase with the input voltage Vin,
At the same time, the output voltage Vo is stabilized.

FIG. 11 is a circuit diagram showing an example of a typical active filter type switching power supply according to another conventional example. The switching power supply mainly comprises a rectifier D
M, a step-up DC-DC converter circuit 10, and an active filter control circuit 20. In the switching power supply, the switching transistor Q of the DC-DC converter circuit 10 is turned on and off to control the line current consumption to be a sine wave having the same phase as the input voltage of the commercial power supply, thereby improving the power factor and fixing the output. Control the voltage.

The rectifier DM receives the input commercial AC Vac
Is subjected to full-wave rectification to generate a pulsating flow Vbc. The generated pulsating flow Vbc is supplied to a DC-DC converter circuit 1 through a filter circuit including a choke coil Lf and a capacitor Cf.
0 is supplied.

The DC-DC converter circuit 10 includes a load 1
9, a switching transistor Q and a smoothing capacitor C arranged in parallel with the load 9, and a choke coil L and a flywheel diode D arranged in series with the load 19. When the switching transistor Q is turned on, a current flows through the choke coil L and energy is stored. When the switching transistor Q is turned off, the energy stored in the choke coil L is released, passes through the flywheel diode D, and passes through the smoothing capacitor C. And supplied to the load 19. The output voltage Vo is determined by the on / off duty ratio of the switching transistor Q.

The active filter control circuit 20 has a DC
While comparing a voltage corresponding to the current iL flowing through the choke coil L of the DC converter circuit 10 with a target voltage proportional to the pulsating voltage Vbc,
Is turned on and off, thereby shaping the input current waveform into a sine waveform having the same phase as the input voltage waveform. At this time, the output voltage is stabilized by adding the detection signal of the output voltage Vo to the target voltage to be compared. This type of circuit is already in the form of an IC and is commercially available (for example, “TDA4814” manufactured by Siemens), and can be configured by adding a few external components.

The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a comparator 26, and a status register 2.
8 and the like. The status register 28 stores N
It comprises an AND gate 28a, an RS flip-flop 28b, an inverter 28c, and an AND gate 28d. The difference between the divided voltage Vf of the output voltage Vo by the voltage dividing resistors R1 and R2 and the DC reference voltage Vrd is amplified by the control amplifier 22, and the control voltage Vs and the AC reference voltage Vr corresponding to the input voltage instantaneous value are amplified.
The product (target voltage) with a is obtained by the multiplier 24. The comparator 26 compares the voltage drop (corresponding to the instantaneous value of the choke current) of the current sense resistor Rs of the switching transistor Q with the target voltage from the multiplier 24, and
8 is controlled.

The comparator 26 resets the status register 28 when the voltage drop of the current sense resistor Rs has reached the target voltage, and sets the status register 28 when the choke coil L has finished discharging. By this operation, the switching transistor Q repeatedly turns on and off, and the choke current iL becomes a triangular wave as shown in FIG.
The peak value corresponds to the target voltage by the multiplier 24,
Since the average input current iin is half of the choke current iL, the average input current iin is shaped into a sine wave having the same phase as the pulsating voltage Vbc, and the output voltage Vo is simultaneously stabilized.

[0014]

The above-mentioned prior art has the following problems. That is, the active filter type switching power supply shown in FIGS. 9 and 11 controls the on / off operation of the switching transistor of the DC-DC converter circuit to make the line consumption current a sine wave in phase with the input voltage, Power supply with greatly improved power factor. However, in an electrophotographic apparatus or the like in which this type of power supply device is incorporated, for example, a circuit having a non-sinusoidal input current is also included, such as a lamp regulator that controls a lamp light amount by changing a voltage applied to the lamp by a phase control method. Therefore, there is a problem that the advantage of the improvement of the power factor cannot be fully utilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has an object to realize a power supply apparatus capable of improving a power factor as a whole of a switching power supply mounting apparatus and reducing input current distortion, and a voltage control of the power supply apparatus. The aim is to provide a method.

[0016]

In order to achieve the above object, a first aspect of the present invention is a power supply having conversion means for converting commercial alternating current to direct current, and constant voltage control means for performing constant voltage control on the conversion means. An apparatus, comprising: detecting means for detecting an input current of a power supply circuit to which the commercial AC is input, wherein the constant voltage control means has a sine wave in a combined value of the input currents of the conversion means and the power supply circuit. Control as described above.

According to another aspect of the present invention, there is provided a rectifier for performing full-wave rectification of a commercial AC, a converter for converting an output of the rectifier to a DC, and a converter for controlling the converter with a target voltage. A constant voltage control unit for performing voltage control, comprising a detection unit that detects an input current of a power supply circuit that receives the commercial AC, and the constant voltage control unit includes:
The target voltage is calculated from the difference between the product of the voltage value obtained from the voltage proportional to the output voltage of the conversion means and the voltage value obtained by full-wave rectification of the commercial AC and the voltage value corresponding to the input current of the power supply circuit. Then, based on a comparison between the target voltage and a voltage corresponding to the input current of the conversion means, control is performed such that a composite value of the input currents of the conversion means and the power supply circuit becomes a sine wave.

In order to achieve the above object, a third aspect of the present invention is characterized in that the power supply circuit is a lamp regulator.

According to a fourth aspect of the present invention, the power supply circuit is a rectifier.

In order to achieve the above object, a fifth aspect of the present invention is characterized in that the detecting means is a current transformer.

In order to achieve the above object, according to a sixth aspect of the present invention, the detecting means is a resistor, and the rectifying means performs full-wave rectification of a commercial alternating current and then applies the rectified current to the constant voltage control means via an insulating means. It is characterized by the following.

In order to achieve the above object, a seventh aspect of the present invention is a voltage control method for a power supply device, comprising: conversion means for converting commercial alternating current to direct current; and constant voltage control means for performing constant voltage control on the conversion means. A detecting step of detecting an input current of a power supply circuit to which the commercial AC is input; and a control step of controlling a combined value of the input currents of the conversion means and the power supply circuit to be a sine wave. Features.

In order to achieve the above object, the invention of claim 8 provides a rectifier for full-wave rectification of commercial AC, a converter for converting the output of the rectifier to DC, and a means for controlling the converter with a target voltage. A voltage control method for a power supply device having constant voltage control means for performing voltage control, comprising: a detection step of detecting an input current of a power supply circuit to which the commercial AC is input; and a voltage proportional to an output voltage of the conversion means. The target voltage is calculated from the difference between the product of the obtained voltage value and the voltage value obtained by full-wave rectification of the commercial AC and the voltage value corresponding to the input current of the power supply circuit,
A control step of controlling the combined value of the input currents of the conversion means and the power supply circuit to be a sine wave based on a comparison between the target voltage and a voltage corresponding to the input current of the conversion means. I do.

In order to achieve the above object, a ninth aspect of the present invention is characterized in that the power supply circuit is a lamp regulator.

To achieve the above object, a tenth aspect of the present invention is characterized in that the power supply circuit is a rectifier.

In order to achieve the above object, an eleventh aspect of the present invention is characterized in that in the detecting step, the current is detected using a current transformer.

According to a twelfth aspect of the present invention, in the detecting step, the detection is performed by using a resistor, the commercial rectifier is subjected to full-wave rectification by the rectifier, and then the constant voltage controller is connected via an insulator. Is applied.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

[1] First Embodiment FIG. 1 is a circuit diagram showing a configuration of a power supply device (active filter type switching power supply) according to a first embodiment. The power supply device is a step-up DC-DC converter circuit 10
, An active filter control circuit 20, and a current transformer CT. Further, a lamp regulator 30 is connected to the power supply device as a power supply circuit to be combined with the power supply device. Since the basic circuit configurations of the step-up DC-DC converter circuit 10 and the active filter control circuit 20 are substantially the same as those shown in FIG. 9, corresponding parts are denoted by the same reference numerals. Will be simplified.

The DC-DC converter circuit 10 includes a choke coil L, a switching transistor Q, a flywheel diode D, a smoothing capacitor C, and a resistor Rs. The choke coil L and the flywheel diode D are connected in series to the load 40, and the switching transistor Q and the smoothing capacitor C are connected in parallel to the load 40.

The current transformer CT is connected to a DC-DC converter circuit 10, an active filter control circuit 20, and a lamp regulator 30, respectively. Further, the switching transistor Q of the DC-DC converter circuit 10 and the negative input terminal of the comparator 26 of the active filter control circuit 20 are connected via a resistor R51. Resistance R5
1 includes a variable resistor VR51 and diodes D51 to D54.
Is connected to the current transformer CT. In the figure, Vin
Is an input voltage, Vo is an output voltage to the load 40, and Vo2 is an output voltage to the lamp 50.

The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a comparator 26, and a status register 2.
8, a configuration including resistors R1, R2, R5 and a capacitor C1. Further, the status register 28 includes a NAND
It comprises a gate 28a, an RS flip-flop 28b, an AND gate 28c, and an inverter 28d. The input terminal of the control amplifier 22 is a DC-DC converter circuit 1
0, and the output terminal is connected to the multiplier 24. The input terminal of the comparator 26 is a multiplier 24 and a DC-DC
The output terminal is connected to the converter circuit 10 and the output terminal is connected to the NAND gate 28 a of the status register 28.

The NAND gate 28a of the status register 28
Are connected to the R input terminal and the S input terminal of the RS flip-flop 28b, respectively. The output terminal of the RS flip-flop 28b is
An inverter 28d is connected to one input terminal of the D gate 28c, and is connected between the other input terminal of the AND gate 28c and the other input terminal of the NAND gate 28a. The output terminal of the AND gate 28c is a DC-D
It is connected to the switching transistor Q of the C converter circuit 10. The active filter control circuit 20 will be described later.

The lamp regulator 30 is an AC constant voltage device that controls the phase angle of conduction with respect to a sine wave by a switch element to change the voltage applied to the lamp to control the amount of lamp light. (Comparison circuit) 32, trigger circuit 33, and waveform shaping circuit 34. Although the lamp regulator 30 is a general circuit, its operation will be briefly described. The triac 31 is inserted in series with the load lamp 50, and controls the switch of the load lamp 50 by a trigger circuit 33 connected to the gate terminal. Detection circuit (comparison circuit) 32
After detecting the lamp voltage and converting it to a predetermined signal level, it generates an error voltage signal by comparing it with a reference voltage and outputs it to the trigger circuit 33.

The waveform shaping circuit 34 shapes the waveform of the input commercial sine wave alternating current, generates a saw-tooth wave of the commercial frequency, and outputs it to the trigger circuit 33. The trigger circuit 33 compares the error voltage signal output from the detection circuit (comparison circuit) 32 with the sawtooth wave output from the waveform shaping circuit 34, determines a trigger phase, and outputs a trigger output to the triac 31. . The triac 31 is controlled by a trigger signal applied from a trigger circuit 33 so as to be turned on at a phase angle corresponding to a target voltage. As described above, the amount of lamp light is stabilized by detecting the lamp voltage and controlling the trigger phase.

To detect the input current of the lamp regulator 30, a current transformer CT is inserted in series with the input. The outputs of the current transformer CT are diodes D51, D52,
Full-wave rectified by D53, D54, VR51, R51
Accordingly, the level adjustment and the detection value of the current sense resistor Rs of the switching transistor Q are superimposed, and the result is applied to the comparator 26 of the active filter control circuit 20.

In the first embodiment of the present invention, in the power supply device (active filter type switching power supply),
The detection value of the current sense resistor Rs of the switching transistor Q of the DC-DC converter circuit 10 (corresponding to the instantaneous value of the choke coil current) and the detection value of the current transformer CT (corresponding to the input current of the lamp regulator 30) Are applied in series to the comparator 26 of the active filter control circuit 20 to compare and control with the target voltage from the multiplier 24.

Next, the detailed operation of the power supply device (active filter type switching power supply) according to the first embodiment will be described. The active filter control circuit 20 of the power supply includes the control amplifier 22 and the multiplier 2 as described above.
4, a comparator 26, a status register 28, and the like. The difference between the divided voltage Vf of the output voltage Vo by the voltage dividing resistors R1 and R2 and the reference voltage Vr is amplified by the control amplifier 22, and the product (target voltage) of the control voltage Vs and the input voltage instantaneous value is multiplied by the multiplier 2
Find in 4. A voltage drop (corresponding to the instantaneous value of the choke current) of the current sense resistor Rs of the switching transistor Q and an output obtained by full-wave rectifying the output of the current transformer CT inserted in series with the lamp regulator 30 (corresponding to the lamp current) ) Is compared with the target voltage from the multiplier 24 by the comparator 26, and the state register 28 is controlled.

The comparator 26 resets the state register 28 when the value obtained by superimposing the voltage drop of the current sense resistor Rs and the output of the current transformer reaches the target voltage, and sets the state when the choke coil L has finished discharging. The register 28 is set. With this operation, the switching transistor Q repeatedly turns on and off. As shown in FIG. 2, in a section where the current of the lamp regulator 30 is zero, the peak value of the choke current iL corresponds to the target voltage by the multiplier 24,
-The average input current i1in of the DC converter circuit 10 becomes half of the choke current iL. As a result, the input voltage V
The output voltage Vo is shaped into a sine wave having the same phase as in, and at the same time, the output voltage Vo is stabilized.

In the section where the lamp current i2in is flowing, a signal corresponding to the instantaneous value of the choke current iL and a signal shown in FIG.
The peak value of the sum with the signal corresponding to the lamp current i2in shown in FIG.
The average input current i1in of the C converter circuit 10 becomes half of the choke current. As a result, the average input current i1in of the DC-DC converter circuit 10 and the lamp current i2i
The combined current iin with n is shaped into a sine wave having the same phase as the input voltage Vin, and at the same time, the output voltage Vo is stabilized.

As described above, according to the first embodiment, the power supply device has the switching transistor Q and converts the commercial alternating current into direct current.
And the control amplifier 22 of the active filter control circuit 20
And a current transformer CT arranged to superimpose a lamp current detection signal of a lamp regulator 30 having the same power supply system as an input in series with a choke coil current detection signal applied to a current detection terminal of the lamp regulator 30. An active filter control circuit 20 that controls the switching transistor Q at a constant voltage so that the combined value of the current consumption and the current consumption of the DC-DC converter circuit 10 is converted into a sine wave. Composite current iin of input current i1in and lamp current i2in
Is shaped into a sine wave in phase with the input voltage Vin. This makes it possible to correct the input current distortion of the lamp regulator 30 having another input current distortion mixed in the device, and to reduce the power factor of the entire device without improving the input current distortion in the lamp regulator 30. Thus, the input current distortion can be reduced.

Note that the power supply device (active filter type switching power supply) according to the first embodiment is not limited to the above configuration. That is, in the first embodiment, a lamp regulator is taken as an example of a power supply circuit combined with a power supply device (active filter type switching power supply). However, the present invention is not limited to this, and a thyristor rectifier or the like in which input current distortion is generated. And other power supply circuits.

[2] Second Embodiment FIG. 4 is a circuit diagram showing a configuration of a power supply device (active filter type switching power supply) according to a second embodiment. The power supply device is a step-up DC-DC converter circuit 10
, An active filter control circuit 20, and a current transformer CT. In the second embodiment, a capacitor input type rectifier circuit 60 is provided in a portion corresponding to the lamp regulator 30 of the first embodiment. Since the basic circuit configurations of the step-up DC-DC converter circuit 10 and the active filter control circuit 20 are substantially the same as those shown in FIG. 1, corresponding parts are denoted by the same reference numerals. Will be simplified.

The DC-DC converter circuit 10 includes a choke coil L, a switching transistor Q, a flywheel diode D, a smoothing capacitor C, and a resistor Rs. The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a comparator 26,
The configuration includes a state register 28, resistors R1, R2, R5, and a capacitor C1. In addition, status register 2
8 is a NAND gate 28a, an RS flip-flop 2
8b, an AND gate 28c and an inverter 28d. The active filter control circuit 20 will be described later. In the figure, Vin is the input voltage, and Vo is the load 4
The output voltage to 0, Vo3 is the output voltage to load 70, D5
1 to D54 are diodes, VR51 is a variable resistor, R51
Is resistance.

The capacitor input type rectifier circuit 60
The configuration includes a diode 61 and an electrolytic capacitor 62. The diode 61 is connected in series to the load 70, and the electrolytic capacitor 62 is connected to the load 7.
0 is connected in parallel. The capacitor input type rectifier circuit 60 is connected to the DC-DC converter circuit 10 and the current transformer CT.
It is connected to the DC converter circuit 10 and the active filter control circuit 20.

In the second embodiment, as in the first embodiment, the peak value of the choke current iL is determined by the multiplier 24 when the input current of the capacitor input type rectifier circuit 60 is zero. DC-D corresponding to voltage
The average input current i1in of the C converter circuit 10 is half of the choke current iL. As a result, the input voltage Vin
And the output voltage Vo is stabilized at the same time.

In the section where the input current of the capacitor input type rectifier circuit 60 flows, the peak of the sum of the signal corresponding to the instantaneous value of the choke current iL and the signal corresponding to the input current i3in of the capacitor input type rectifier circuit 60 is obtained. The value corresponds to the target voltage by the multiplier 24, DC-DC
The average input current i1in of the converter circuit 10 is half of the choke current iL. As a result, the combined current iin of the average input current i1in of the DC-DC converter circuit 10 and the input current i3in of the capacitor input rectifier circuit 60 is shaped into a sine wave having the same phase as the input voltage Vin.
At the same time, the output voltage Vo is stabilized.

As described above, according to the second embodiment, the power supply device has the switching transistor Q and converts the commercial alternating current into direct current.
And the control amplifier 22 of the active filter control circuit 20
A current transformer CT arranged to superimpose a current detection signal of a capacitor input type rectifier circuit 60 having the same power supply system as an input in series with a choke coil current detection signal applied to a current detection terminal of 30 so that the combined value of the current consumption of the DC-DC converter circuit 10 and the current consumption of the DC-DC converter circuit 10 is converted into a sine wave.
And an active filter control circuit 20 for controlling the average input current i1in of the DC-DC converter circuit 10 and the capacitor input type rectifier circuit 6.
The combined current iin with the input current i3in of 0 is shaped into a sine wave having the same phase as the input voltage Vin. This makes it possible to correct the input current distortion of the capacitor input type rectifier circuit 60 having other input current distortions mixed in the device, without improving the input current distortion in the capacitor input type rectifier circuit 60. The power factor of the entire device is improved, and the input current distortion can be reduced.

The power supply device (active filter type switching power supply) according to the second embodiment is not limited to the above configuration. That is, in the second embodiment, a capacitor input type rectifier circuit is taken as an example of a power supply circuit combined with a power supply device (active filter type switching power supply). However, the present invention is not limited to this. The present invention is also applicable to other power supply circuits such as a rectifier.

[3] Third Embodiment FIG. 5 is a circuit diagram showing a configuration of a power supply device (active filter type switching power supply) according to a third embodiment. The power supply device is a step-up DC-DC converter circuit 10
, Active filter control circuit 20, rectifier DM
And a current detection circuit 80. still,
The basic circuit configuration of the step-up DC-DC converter circuit 10 and the active filter control circuit 20 is as shown in FIG.
Are substantially the same as those described above, and corresponding parts are denoted by the same reference numerals, and description thereof will be simplified.

The DC-DC converter circuit 10 includes a choke coil L, a switching transistor Q, a flywheel diode D, a smoothing capacitor C, and a resistor Rs. The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a subtractor 25,
Comparator 26, status register 28, resistors R1, R2, R
5, a configuration including a capacitor C1. Furthermore,
The status register 28 includes a NAND gate 28a, an RS flip-flop 28b, an AND gate 28c, and an inverter 28d. The active filter control circuit 20 will be described later. In the drawing, Vin is an input voltage, Vo is an output voltage to the load 19, R3 and R4 are resistors,
Lf is a choke coil, and Cf is a capacitor.

The lamp regulator 30 is connected to the power supply as a power supply circuit to be combined with the power supply. The lamp regulator 30 is a triac 3
1, a detection circuit (comparison circuit) 32, a trigger circuit 33, and a waveform shaping circuit 34. The lamp regulator 30 will be described later. Further, the line current consumption of the lamp regulator 30 (hereinafter, lamp current ilmp
Current detecting circuit 80 is connected in series with the input. The current detection circuit 80 includes a current transformer CT51, a rectifier DM51, and resistors R51 and R52, detects a lamp current ilmp, converts the lamp current ilmp to a corresponding voltage value, and outputs the voltage value. Current detection circuit 8
0 will be described later.

The basic configuration of the active filter control circuit 20 of the power supply device (active filter type switching power supply) according to the third embodiment is different from the conventional example shown in FIG. 26, a subtractor 25 is added. The output of the multiplier 24 is applied to the subtracter 25, the subtracter 25 subtracts the voltage by the voltage value corresponding to the lamp current ilmp detected by the current transformer CT <b> 51, and outputs the result to the comparator 26.

Next, the detailed operation of the power supply according to the third embodiment will be described. First, the operation of the lamp regulator 30 will be briefly described as to a general circuit. The triac 31 is inserted in series with the load lamp 39, and controls the switch of the load lamp 39 by a trigger circuit 33 connected to the gate terminal. The detection circuit (comparison circuit) 32 detects the lamp voltage, converts it to a predetermined signal level, compares it with a reference voltage, generates an error voltage signal, and outputs it to the trigger circuit 33. The waveform shaping circuit 34 shapes the waveform of the input commercial sine wave AC,
A saw-tooth wave of a commercial frequency is generated and output to the trigger circuit 33.

The trigger circuit 33 is a detection circuit (comparison circuit)
The error voltage signal output from the signal generator 32 is compared with the sawtooth wave output from the waveform shaping circuit 34 to determine a trigger phase, and a trigger output is output to the triac 31. The triac 31 is controlled by a trigger signal applied from a trigger circuit 33 so as to be turned on at a phase angle corresponding to a target voltage. As described above, the amount of lamp light is stabilized by detecting the lamp voltage and controlling the trigger phase.

Next, the current detecting circuit 80 for detecting the lamp current ilmp will be described. As described above, the current detection circuit 80 is inserted in series with the input to detect the lamp current ilmp. The current detection circuit 80 includes a current transformer CT5
One primary winding is inserted in series with the input of the lamp regulator 30, and a current corresponding to the turn ratio is output from the secondary winding. The output of the secondary winding is full-wave rectified by a rectifier DM51, current / voltage conversion and level adjustment are performed by resistors R51 and R52, and the active filter control circuit 20
Is applied to the subtraction terminal of the subtractor 25.

Next, the active filter control circuit 20 and the DC-DC converter circuit 10 will be described. The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a subtractor 25, a comparator 26,
A status register 28 and the like are provided. The difference between the divided voltage Vf of the output voltage Vo by the voltage dividing resistors R1 and R2 and the DC reference voltage Vr is amplified by the control amplifier 22, and the product of the control voltage Vs and the voltage value corresponding to the instantaneous input voltage value is multiplied by the multiplier. Determined by 24. The lamp current ilm is compared with the value obtained by the multiplier 24.
Subtraction of the voltage value corresponding to p is performed by the subtractor 25, and this is set as a target voltage. The comparator 2 compares the voltage drop (corresponding to the instantaneous value of the choke current) of the current sense resistor Rs of the switching transistor Q with the target voltage from the subtractor 25.
6 to control the status register 28.

The comparator 26 resets the status register 28 when the voltage drop of the current sense resistor Rs reaches the above-mentioned target voltage, and sets the status register 28 when the choke coil L has finished discharging. With this operation, the switching transistor Q repeatedly turns on and off. As shown in FIG. 6 and FIG. 7, the section T where the lamp current ilmp is zero is shown.
At 1, the product of the control voltage Vs corresponding to the output voltage Vo and the AC reference voltage Vra corresponding to the instantaneous value of the input voltage is determined by the multiplier 24 and applied to the subtractor 25. Is zero, the input and output values of the subtractor 25 become equal, and the output of the multiplier becomes the target voltage. That is, the target voltage has a pulsating waveform corresponding to the output voltage Vo and the pulsating voltage Vbc.

The peak value of the choke current iL is calculated by the multiplier 2
4, the average input current iin of the DC-DC converter circuit 10 becomes half of the choke current iL. As a result, the input current iac corresponding to the average input current iin of the DC-DC converter circuit 10 is shaped into a sine wave in phase with the input voltage Vac, and at the same time, the output voltage Vo
Is stabilized. In the section T2 in which the lamp current ilmp flows, the multiplier 24 obtains the product of the control voltage Vs corresponding to the output voltage Vo and the AC reference voltage Vra corresponding to the instantaneous value of the input voltage, and is applied to the subtractor 25. A voltage value corresponding to the line current consumption of the lamp regulator 30 is applied to the subtraction terminal of the subtractor 25, and the subtraction terminal 25 subtracts the voltage value to obtain the target voltage.

The target voltage is the output voltage Vo and the pulsating voltage Vb
The waveform obtained by subtracting the voltage corresponding to the lamp current ilmp from the pulsating waveform corresponding to c is the target voltage. The peak value of the choke current iL corresponds to the target voltage, and the average input current iin of the DC-DC converter circuit 10 becomes half of the choke current iL. As a result, the input current iac, which is a combined current of the average input current iin and the lamp current ilmp of the DC-DC converter circuit 10, is shaped into a sine wave having the same phase as the input voltage Vac, and at the same time, the output voltage Vo is stabilized. .

As described above, according to the third embodiment, the power supply device has the switching transistor Q and converts the commercial AC into DC.
And a current detection circuit 80 for detecting a lamp current ilmp
And a control voltage obtained by amplifying a difference between a voltage proportional to an output voltage of the DC-DC converter circuit 10 and a fixed reference voltage by the control amplifier 22 and a voltage obtained by dividing a pulsating current obtained by full-wave rectifying commercial AC by resistance division. , And further converts the line current consumption of the lamp regulator 30 having the same power supply system as an input into a voltage value, and subtracts the difference from the multiplier output into the subtractor 2.
5 to obtain a target voltage. The comparator 26 compares and controls the input current of the DC-DC converter circuit 10 or the switch current of the switching transistor Q to obtain a combined value of the input currents of the DC-DC converter circuit 10 and the lamp regulator 30. Filter control circuit 20 for controlling switching transistor Q at a constant voltage so that
Therefore, the input current iac, which is a combined current of the average input current iin and the lamp current ilmp of the DC-DC converter circuit 10, is shaped into a sine wave having the same phase as the input voltage Vac. This makes it possible to correct the input current distortion of the lamp regulator 30 having another input current distortion mixed in the device, and to reduce the power factor of the entire device without improving the input current distortion in the lamp regulator 30. Thus, the input current distortion can be reduced.

The power supply device (active filter type switching power supply) according to the third embodiment is not limited to the above configuration. That is, in the third embodiment, a lamp regulator is taken as an example of a power supply circuit combined with a power supply device (active filter type switching power supply). However, the present invention is not limited to this, and a thyristor rectifier circuit in which input current distortion occurs, It is also applicable to other power supply circuits such as a capacitor input rectifier circuit.

[4] Fourth Embodiment FIG. 8 is a circuit diagram showing a configuration of a power supply device (active filter type switching power supply) according to a fourth embodiment. The power supply device is a step-up DC-DC converter circuit 10
, Active filter control circuit 20, rectifier DM
And a current detection circuit 90. still,
Since the basic circuit configurations of the step-up DC-DC converter circuit 10 and the active filter control circuit 20 are the same as those shown in FIG. 5, corresponding portions are denoted by the same reference numerals, and description thereof will be made. Is simplified.

The DC-DC converter circuit 10 includes a choke coil L, a switching transistor Q, a flywheel diode D, a smoothing capacitor C, and a resistor Rs. The active filter control circuit 20 includes a control amplifier 22, a multiplier 24, a subtractor 25,
Comparator 26, status register 28, resistors R1, R2, R
5, a configuration including a capacitor C1. Furthermore,
The status register 28 includes a NAND gate 28a, an RS flip-flop 28b, an AND gate 28c, and an inverter 28d. In the drawing, Vin is an input voltage, Vo is an output voltage to the load 19, R3 and R4 are resistors,
Lf is a choke coil, and Cf is a capacitor.

Further, a lamp regulator 30 is connected to the power supply as a power supply circuit to be combined with the power supply. The lamp regulator 30 is a triac 3
1, a detection circuit (comparison circuit) 32, a trigger circuit 33, and a waveform shaping circuit 34. Further, as means for detecting the lamp current ilmp, a current detection circuit 90 using a detection resistor different from that of the third embodiment is connected to the input. The current detection circuit 90 includes a detection resistor R
91, inverting amplifier 91, buffer amplifier 92, inverting amplifier 9
3. PWM (Pulse Width Modulation) modulator 9
4. Photocoupler 95, integrator 96, diodes 97, 9
8 is provided.

In the fourth embodiment, similarly to the third embodiment, the active filter control is performed in consideration of the lamp current ilmp. As a result, the input current iac has the same phase as the input voltage Vac. The output voltage Vo is shaped into a sine wave, and at the same time, the output voltage Vo is stabilized.

In the current detection circuit 90, a current detection resistor R 61 is inserted in series with the input line of the lamp regulator 30, and a signal detected by the current detection resistor R 61 is amplified by an inverting amplifier 91 to a predetermined level. The two signals are inverted in phase by the buffer amplifier 92 having a gain of 1 and the inverting amplifier 93 having a gain of 1. The signals are half-wave rectified by diodes 97 and 98, respectively, and then combined to be full-wave rectified. The full-wave rectified pulsating signal is applied to the PWM modulator 94. The PWM modulator 94 performs PWM modulation by comparing the applied pulsating flow with the sawtooth wave. The PWM-modulated signal is insulated by a photocoupler 95 and applied to an integrator 96. The integrator 96 demodulates the applied PWM modulated signal into a pulsating signal. The demodulated pulsating signal is applied to the subtraction terminal of the subtractor 25 as a voltage value corresponding to the lamp current ilmp.

Other operations are the same as those in the third embodiment. Also in the fourth embodiment, as shown in FIGS. 6 and 7, in the section T1 where the lamp current ilmp is zero, the control voltage Vs corresponding to the output voltage Vo and the AC reference voltage Vra corresponding to the input voltage instantaneous value. Is obtained by the multiplier 24 and applied to the subtractor 25. Since the voltage value applied to the subtraction terminal is zero, the input and output values of the subtractor 25 become equal, and the output of the multiplier becomes the target voltage. Becomes That is, the target voltage has a pulsating waveform corresponding to the output voltage Vo and the pulsating voltage Vbc.

The peak value of the choke current iL is determined by the multiplier 2
4, the average input current iin of the DC-DC converter circuit 10 becomes half of the choke current iL. As a result, the input current iac corresponding to the average input current iin of the DC-DC converter circuit 10 is shaped into a sine wave in phase with the input voltage Vac, and at the same time, the output voltage Vo
Is stabilized. In the section T2 in which the lamp current ilmp flows, the multiplier 24 obtains the product of the control voltage Vs corresponding to the output voltage Vo and the AC reference voltage Vra corresponding to the instantaneous value of the input voltage, and is applied to the subtractor 25. A voltage value corresponding to the line current consumption of the lamp regulator 30 is applied to the subtraction terminal of the subtractor 25, and the subtraction terminal 25 subtracts the voltage value to obtain the target voltage.

The target voltage is the output voltage Vo and the pulsating voltage Vb
The waveform obtained by subtracting the voltage corresponding to the lamp current ilmp from the pulsating waveform corresponding to c is the target voltage. The peak value of the choke current iL corresponds to the target voltage, and the average input current iin of the DC-DC converter circuit 10 is equal to the choke current iL.
It is half of L. As a result, the input current iac, which is a combined current of the average input current iin and the lamp current ilmp of the DC-DC converter circuit 10, is shaped into a sine wave having the same phase as the input voltage Vac, and at the same time, the output voltage Vo is stabilized. .

As described above, according to the fourth embodiment, the power supply device has the switching transistor Q and converts the commercial alternating current into direct current.
And a current detection circuit 90 for detecting a lamp current ilmp
And a control voltage obtained by amplifying a difference between a voltage proportional to an output voltage of the DC-DC converter circuit 10 and a fixed reference voltage by the control amplifier 22 and a voltage obtained by dividing a pulsating current obtained by full-wave rectifying commercial AC by resistance division. , And further converts the line current consumption of the lamp regulator 30 having the same power supply system as an input into a voltage value, and subtracts the difference from the multiplier output into the subtractor 2.
5 to obtain a target voltage. The comparator 26 compares and controls the input current of the DC-DC converter circuit 10 or the switch current of the switching transistor Q to obtain a combined value of the input currents of the DC-DC converter circuit 10 and the lamp regulator 30. Filter control circuit 20 for controlling switching transistor Q at a constant voltage so that
Therefore, the input current iac, which is a combined current of the average input current iin and the lamp current ilmp of the DC-DC converter circuit 10, is shaped into a sine wave having the same phase as the input voltage Vac. This makes it possible to correct the input current distortion of the lamp regulator 30 having another input current distortion mixed in the device, and to reduce the power factor of the entire device without improving the input current distortion in the lamp regulator 30. Thus, the input current distortion can be reduced.

The power supply device (active filter type switching power supply) according to the fourth embodiment is not limited to the above configuration. That is, in the fourth embodiment, a lamp regulator is taken as an example of a power supply circuit combined with a power supply device (active filter type switching power supply). However, the present invention is not limited to this, and a thyristor rectifier circuit in which input current distortion occurs, It is also applicable to other power supply circuits such as a capacitor input rectifier circuit.

[0073]

As described above, according to the first aspect of the present invention, there is provided a power supply apparatus having conversion means for converting commercial alternating current to direct current, and constant voltage control means for performing constant voltage control on the conversion means. Detecting means for detecting an input current of a power supply circuit to which the commercial AC is input, wherein the constant voltage control means controls the combined value of the input currents of the conversion means and the power supply circuit to be a sine wave. Therefore, the combined value of the input currents of the conversion means and the power supply circuit is a sine wave in phase with the input voltage. This makes it possible to correct the input current distortion of the power supply circuit having another input current distortion mixed in the device, and to improve the power factor of the entire device without improving the input current distortion in each power supply circuit. Thus, the input current distortion can be reduced.

According to the second aspect of the invention, rectifying means for full-wave rectification of commercial AC, conversion means for converting the output of the rectification means to DC, and constant voltage for controlling the conversion means at a constant voltage with a target voltage. A power supply device having control means, wherein the constant voltage control means has a detection means for detecting an input current of a power supply circuit to which the commercial AC is input, and wherein the constant voltage control means detects a voltage proportional to an output voltage of the conversion means. A target voltage is calculated from a difference between a product of the obtained voltage value and a voltage value obtained by full-wave rectification of the commercial alternating current and a voltage value corresponding to the input current of the power supply circuit, and the target voltage and the input of the conversion means are calculated. Based on the comparison with the voltage corresponding to the current, the combined value of the input current of the conversion means and the power supply circuit is controlled to be a sine wave. It becomes an in-phase sine wave. This makes it possible to correct the input current distortion of the power supply circuit having another input current distortion mixed in the device, and to improve the power factor of the entire device without improving the input current distortion in each power supply circuit. Thus, the input current distortion can be reduced.

According to the third aspect of the present invention, since the power supply circuit is a lamp regulator, the input current distortion of the entire apparatus can be reduced without improving the input current distortion by the lamp regulator.

According to the invention of claim 4, since the power supply circuit is a rectifier, the input current distortion of the entire device can be reduced without improving the input current distortion in the rectifier.

According to the fifth aspect of the present invention, since the detecting means is a current transformer, it is possible to accurately detect the input current of the power supply circuit to which commercial AC is input by using the current transformer.

According to the invention of claim 6, the detecting means is a resistor, and the rectifying means applies full-wave rectification to the constant voltage control means through the insulating means after the commercial rectification is applied. The input current of the power supply circuit to be input can be accurately detected by using a resistor.

According to a seventh aspect of the present invention, there is provided a voltage control method for a power supply apparatus, comprising: conversion means for converting commercial alternating current into direct current; and constant voltage control means for performing constant voltage control on the conversion means. The method according to claim 1, further comprising a detection step of detecting an input current of a power supply circuit to which an alternating current is input, and a control step of controlling the combined value of the input currents of the conversion means and the power supply circuit to be a sine wave. Similarly to the invention, it is possible to correct the input current distortion of the power supply circuit having another input current distortion mixed in the device, and to improve the input current of the entire device without improving the input current distortion in each power supply circuit. Current distortion can be reduced.

According to the eighth aspect of the invention, a rectifier for full-wave rectification of commercial AC, a converter for converting the output of the rectifier to DC, and a constant voltage for controlling the converter with a target voltage at a constant voltage. A voltage control method of a power supply device having a control means, wherein a detection step of detecting an input current of a power supply circuit to which the commercial AC is input, a voltage value obtained from a voltage proportional to an output voltage of the conversion means, and A target voltage is calculated from the difference between the product of the voltage values obtained by full-wave rectification of the commercial AC and the voltage value corresponding to the input current of the power supply circuit, and the target voltage and the voltage corresponding to the input current of the conversion means are calculated. And a control step for controlling the combined value of the input currents of the conversion means and the power supply circuit to be a sine wave based on the comparison with the control means. Input current distortion It is possible to correct the input current distortion in the circuit, without the improvement of the input current distortion in each of the power supply circuit, it becomes possible to reduce the input current distortion of the entire device.

According to the ninth aspect of the present invention, since the power supply circuit is a lamp regulator, the same effect as that of the third aspect of the invention can be obtained.

According to the tenth aspect of the present invention, since the power supply circuit is a rectifier, the same effects as those of the fourth aspect of the invention can be obtained.

According to the eleventh aspect of the present invention, in the detecting step, the current is detected by using a current transformer.

According to the twelfth aspect of the present invention, in the detecting step, detection is performed using a resistor, and after the commercial rectification is full-wave rectified by the rectification means, it is applied to the constant voltage control means via an insulation means. The same effect as that of the sixth aspect is obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a power supply device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the power supply device according to the first embodiment of the present invention.

FIG. 3 is an operation waveform diagram of the lamp regulator according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a power supply device according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram showing a configuration of a power supply device according to a third embodiment of the present invention.

FIG. 6 is an operation waveform diagram of a power supply device according to a third embodiment of the present invention.

FIG. 7 is an operation waveform diagram of the lamp regulator according to the third embodiment of the present invention.

FIG. 8 is a circuit diagram showing a configuration of a power supply device according to a fourth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a power supply device according to a conventional example.

FIG. 10 is an operation waveform diagram of a power supply device according to a conventional example.

FIG. 11 is a circuit diagram showing a configuration of a power supply device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 10 DC-DC converter circuit 20 Active filter control circuit 22 Control amplifier 24 Multiplier 25 Subtractor 26 Comparator 30 Lamp regulator 60 Capacitor input type rectifier circuit 80, 90 Current detection circuit 91, 93 Inverting amplifier 92 Buffer amplifier 94 PWM modulator 95 Photocoupler 96 Integrator CT, CT51 Current transformer DM, DM51 Rectifier

Claims (12)

[Claims] A converter for converting commercial AC into DC;
A constant voltage control unit that controls the conversion unit with a constant voltage, comprising: a detection unit that detects an input current of a power supply circuit that receives the commercial alternating current, wherein the constant voltage control unit includes: A power supply device that controls a combined value of input currents of a conversion unit and a power supply circuit to be a sine wave. 2. A power supply apparatus comprising: a rectifier for performing full-wave rectification of a commercial alternating current; a converter for converting an output of the rectifier to a direct current; and a constant voltage controller for performing constant voltage control of the converter with a target voltage. And a detecting means for detecting an input current of a power supply circuit to which the commercial AC is input, wherein the constant voltage control means includes a voltage value obtained from a voltage proportional to an output voltage of the conversion means and a commercial AC voltage. The target voltage is calculated from the difference between the product of the voltage values obtained by full-wave rectification and the voltage value corresponding to the input current of the power supply circuit, and the target voltage and the voltage corresponding to the input current of the conversion means are calculated. A power supply device, based on the comparison, controlling the combined value of the input currents of the conversion means and the power supply circuit to be a sine wave. 3. The power supply device according to claim 1, wherein the power supply circuit is a lamp regulator. 4. The power supply device according to claim 1, wherein the power supply circuit is a rectifier. 5. The power supply device according to claim 1, wherein said detecting means is a current transformer. 6. The power supply device according to claim 2, wherein the detection means is a resistor, and the commercial AC is full-wave rectified by the rectification means and then applied to the constant voltage control means via an insulation means. . 7. Conversion means for converting commercial AC to DC,
What is claimed is: 1. A voltage control method for a power supply device, comprising: a constant voltage control unit that controls a constant voltage of a conversion unit; a detection step of detecting an input current of a power supply circuit that receives the commercial AC; Controlling the combined value of the input currents to be a sine wave. 8. A power supply apparatus comprising: a rectifier for performing full-wave rectification of a commercial alternating current; a converter for converting an output of the rectifier to a direct current; and a constant voltage controller for performing constant voltage control of the converter with a target voltage. A voltage control method, comprising: a detecting step of detecting an input current of a power supply circuit to which the commercial AC is input; and a full-wave rectification of a voltage value and a commercial AC obtained from a voltage proportional to an output voltage of the conversion unit. A target voltage is calculated from a difference between the product of the obtained voltage values and a voltage value corresponding to the input current of the power supply circuit, and based on a comparison between the target voltage and a voltage corresponding to the input current of the conversion means, A control step of controlling the combined value of the input current of the conversion means and the power supply circuit to be a sine wave. 9. The voltage control method for a power supply device according to claim 7, wherein the power supply circuit is a lamp regulator. 10. The voltage control method for a power supply device according to claim 7, wherein the power supply circuit is a rectifier. 11. The voltage control method for a power supply device according to claim 7, wherein the detection is performed using a current transformer. 12. The method according to claim 8, wherein in the detecting step, a commercial alternating current is full-wave rectified by the rectifier and then applied to the constant voltage controller via an insulator. Voltage control method for a power supply device.