JPH09289770A - Power factor converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain DC output which has no distortion in AC input current and whose output ripple voltage is small. SOLUTION: This device is provided, in a converter circuit which is connected to a rectification circuit 2 which rectifies AC input power and consists of a switching element 31, a diode 42, a choke coil 51 and a capacitor 61, with an auxiliary circuit constituted of a capacitor 62 which is charged through diodes 43, 45 and a choke coil 52 from an output of the switching element 31, and a switching element 32 which supplies power stored in the capacitor 62 into the choke coil 51 of the converter circuit. As a result, the switching element 31 is controlled so that AC input current may become a sinewave, and output voltage is controlled so as to be constant voltage without the switching element 32 being turned on together with the switching element 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high power factor converter, and more particularly, by making an AC input current supplied from an AC power source a sine wave, the input power factor is improved and harmonics are suppressed, and the DC output The present invention relates to a high power factor converter that ensures reduction of ripple.

[0002]

2. Description of the Related Art A high power factor converter circuit that obtains a desired DC with AC as an input is connected to the DC side of a rectifier circuit that rectifies the AC power from an AC input power source, and makes the AC input current sinusoidal. , A converter that stabilizes the voltage on the DC side. Conventionally known as this method are, for example, a step-up type, a step-up / down type, and a step-down type shown in FIG. 23, which are described in JP-A-4-289774.

A conventional circuit example will be described below with reference to the step-down type shown in FIG.

One DC terminal a and the other DC terminal b of the rectifier circuit 2 for full-wave rectifying the AC power from the AC input power supply 1.
, The switching element 3 and the diode 4 are connected in series, and the choke coil 5 and the capacitor 6 are connected in series in parallel with the diode 4 to control the control circuit 100.
By controlling the ON / OFF ratio of the switching element 3 in accordance with the change of the AC input voltage by the control output of, the AC input current of the rectifier circuit 2 is made sinusoidal, and the high frequency wave connected to the AC side of the rectifier circuit 2 is controlled. A high frequency component is removed from the AC input current by the filter 7 to form a sine wave.

Next, the above-mentioned operation of the control circuit 100 of this step-down type high power factor converter circuit will be described. The control circuit 100 compares an absolute value circuit 101 for converting an AC input voltage corresponding voltage into an absolute value and an output voltage of the absolute value circuit 101 and a triangular wave voltage 1021 having a frequency sufficiently higher than the frequency of the AC input power supply. Circuit 102,
And a drive circuit 103 for converting the output of the comparison circuit 102 into a drive signal 1031 for the switching element 3, and compares the output voltage of the absolute value circuit 101 with the triangular wave voltage.
Then, the drive circuit 103 generates the drive signal 1031 for turning on the switching element 3 in the section where the output voltage of the absolute value circuit 101 is higher than the triangular wave voltage.

Therefore, the switching element 3 has a structure shown in FIG.
25, a current flows for a longer period in a section where the peak value of the AC input voltage is higher, a current as shown in FIG. 25 flows on the AC side of the rectifier circuit 2, and the AC input current is high frequency by the high frequency filter 7. The component can be removed to form a perfect sine wave in phase with the AC input voltage.

[0007]

However, the above-described conventional high power factor converter circuit, regardless of whether it is a step-down type, a step-up type or a step-up / down type, has no relation to the switching frequency for controlling the AC input current into a sine wave. A ripple voltage corresponding to the AC input frequency determined by the rectifier circuit system is generated on the DC output side, and, for example, in the case of single-phase bridge rectification, a ripple having a frequency twice the AC input frequency is generated. Also,
In the case of FIG. 23, the inductance of the choke coil 5 needs to be very large in order to maintain the current continuity at the input AC frequency.

When a passive element is used to reduce the above-mentioned ripple voltage, the filter on the DC output side, that is, the choke coil 5 and the capacitor 6 in the case of FIG. Since the peak value of the flowing current must be constant as shown in FIG. 24, the choke coil and the capacitor become very large and the cost becomes high.

Further, as a method of using an active element for reducing the ripple voltage, for example, the above-mentioned Japanese Patent Laid-Open No. Hei 4-
As described in Japanese Patent No. 289774, a method of connecting a DC-DC converter in the latter stage without voltage conversion, or a method of canceling this ripple voltage in a DC output including a ripple voltage, as in Japanese Patent Laid-Open No. 3-1664068. There is a method to reduce the ripple voltage by separately creating and applying a DC voltage with polarity, but both are control after DC conversion once, and there are many problems in terms of efficiency, price and size. There is a drawback that.

Except for the above-mentioned drawbacks, the object of the present invention is to fundamentally eliminate the distortion of the AC input current by making the AC input current in phase and with the same waveform as the AC input voltage, and to significantly reduce the ripple voltage included in the DC output. It is to provide a high power factor converter having a highly efficient and simple configuration that can be suppressed.

[0011]

In order to achieve the above-mentioned object, the high power factor converter of claim 1 of the present invention has the following means configuration.

That is, the high power factor converter of the present invention is a step-down type, step-up type or step-up / down type which ensures the improvement of the input power factor, the suppression of harmonics, and the ripple reduction of the DC output by making the AC input current a sine wave. In the high power factor converter, a rectifier circuit for full-wave rectifying an AC input power source, and a first switching element driven by a DC output voltage output from the rectifier circuit at a frequency sufficiently higher than the frequency of the AC input power source. A switching circuit for switching and outputting with a switch, an output circuit for forming an output filter by connecting a first choke coil and a first capacitor so as to smooth the output of the switching circuit and supply it to a load, 1
A charging circuit including a series connection of a second capacitor and a second choke coil arranged between the first switching element and the output circuit to charge the output of the switching element of A charging voltage applying circuit that applies a charging voltage of a second capacitor to the output circuit via a second switching element, and an output of the switching circuit and an output of the charging voltage applying circuit are alternately sent to the output circuit. The first switching element and the second switching element
So that the sum of the electric powers supplied to the output circuit via the switching element of
And a control circuit for controlling the switching element of.

According to a second aspect of the present invention, in the high power factor converter, the waveform of the AC input current to the rectifier circuit is a sine wave, and the charging voltage of the second capacitor is a constant voltage. It has a configuration including a control circuit for controlling one switching element with a predetermined first pulse width modulation signal.

According to a third aspect of the present invention, in the high power factor converter, the second switching element is driven so as not to output at the same time as the first switching element, and the output circuit to be applied to the load. And a control circuit for controlling the second switching element with a predetermined second pulse width modulation signal so that the DC output voltage is constant.

According to a fourth aspect of the present invention, in the high power factor converter, a first detection voltage obtained by detecting an output current of the first switching element, the AC input power source, and the AC input power source are provided. Based on a reset signal of a frequency sufficiently higher than that and a reset signal of an oscillator that outputs a sawtooth wave, so that the AC input current of the full-wave rectifier circuit has a waveform synchronized with the voltage of the AC input power supply. A second detection voltage obtained by detecting the conduction current of the first choke coil while outputting the first pulse width modulation signal for controlling the operation of the first switching element, and the first capacitor. Power supplied to the load side via the first switching element and the second switch based on the charging voltage of the oscillator, the sawtooth wave of the oscillator, and the first pulse width modulation signal. A control circuit that outputs the second pulse width modulation signal that controls the operation of the second switching element so that the sum of the power supplied to the load side via the switching element is constant for each pulse. It has a different configuration.

A high power factor converter according to a fifth aspect of the present invention is a high frequency transformer for converting a switching voltage formed by the first and second switching elements or an insulating transformer for separating an input side and an output side. It has a configuration including.

Further, the invention according to claim 6 is of a step-down type, a step-up type or a step-up / down type which secures the improvement of the input power factor, the suppression of harmonics and the ripple reduction of the DC output by making the AC power supply current a sine wave. In a high power factor converter, a rectifier circuit for full-wave rectifying AC power, and a first switching element for driving a DC voltage output from the rectifier circuit at a frequency sufficiently higher than the frequency of the AC power supply. A third switching circuit having a first switching circuit and a third switching element is connected to a first choke coil and a first capacitor in order to smooth the output of the first switching circuit and supply it to a load. An output circuit forming an output filter between the third switching circuit and the output circuit to charge the output of the third switching circuit. A charging circuit including a serial connection of the arranged second choke coil and a second capacitor; and a charging voltage applying circuit for applying the charging voltage of the second capacitor to the output circuit via a second switching element. , The output of the first switching circuit and the output of the charging voltage applying circuit are alternately sent to the output circuit so that the sum of the electric power supplied to the output circuit is always constant. And a control circuit for controlling the switching element of No. 3.

According to a seventh aspect of the present invention, in the high power factor converter according to the sixth aspect, the control circuit causes the waveform of the AC power supply current to the rectifier circuit to be a sine wave and the charging voltage of the second capacitor. Is provided with a function of controlling the first and third switching elements with the first and third pulse width modulation signals so that the voltage becomes a constant voltage.

According to an eighth aspect of the present invention, in the high power factor converter according to the sixth aspect, the control circuit is driven so that the second switching element and the first switching element do not output simultaneously. In addition, it has a function of controlling the second switching element with a second pulse width modulation signal so that the DC output voltage from the output circuit to be applied to the load becomes a constant voltage.

According to a ninth aspect of the present invention, in the high power factor converter according to the seventh or eighth aspect, the control circuit detects a direct current of the rectifier circuit, a first detected voltage, and a rectifier circuit. The direct current voltage and a signal of an oscillator that outputs a sawtooth wave having a frequency sufficiently higher than the frequency of the alternating current power supply, and the alternating current of the rectifier circuit has a waveform synchronized with the alternating current power supply voltage. A pulse width modulation signal of 1, and a third detection voltage obtained by detecting the first detection voltage, the charging voltage of the second capacitor, and the conduction current of the third switching element, Based on the sawtooth wave, outputs the third pulse width modulation signal that causes the alternating current of the rectifier circuit to have a waveform synchronized with the alternating current power supply voltage, and outputs the direct current output voltage by the output circuit, One chalk Power supplied to the load via the first switching element and the second switching element based on the second detection voltage obtained by detecting the conduction current of the coil and the sawtooth wave. The second power supply unit to keep the sum of the power supplied to the load constant for each pulse.
Of the pulse width modulation signal.

According to a tenth aspect of the present invention, in the high power factor converter according to the sixth, seventh, eighth or ninth aspect,
A high frequency transformer for converting the output of the first switching circuit and the output of the charging voltage applying circuit into an output circuit or an insulating transformer for insulating the first switching circuit and the charging voltage applying circuit from the output circuit. It is characterized by including.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In a conventional high power factor converter circuit for obtaining a desired DC from an AC using a switching element,
When the AC input current is controlled to a sine wave, a ripple voltage corresponding to the AC input frequency determined by the rectifier circuit system is generated on the DC output side regardless of the switching frequency.

When a passive element is used to reduce the ripple voltage, the values of the choke coil and the capacitor that form the filter on the DC output side must be made very large to make the peak value of the switching element current constant. Therefore, the choke coil and the capacitor become very large and the price becomes high.

Further, when adopting the method of using the active element to reduce the ripple voltage, the control is performed after the DC voltage is once applied, and there are many problems in terms of efficiency, price and size.

In the first, second, third, fourth and fifth aspects of the present invention, the first switching element (31 in FIG. 1) is controlled so as to have a waveform in which the AC input current is synchronized with the AC input voltage. To do. In addition, the second switching element (32 in FIG. 1)
Is controlled so that the sum of the electric power supplied from the first switching element to the output side and the electric power supplied from the second switching element to the output side is constant for each pulse. Can be made to have the same waveform and phase as the AC input voltage, the ripple voltage of the DC output can be significantly reduced, and the filter on the DC output side can be made smaller. This is an embodiment of the invention.

According to the sixth, seventh, eighth and ninth aspects of the present invention, the AC power supply current is controlled by the first switching element and the third switching element to have a waveform synchronized with the AC power supply voltage. By controlling the sum of the electric power supplied to the load from the first switching element and the electric power supplied to the load from the second switching element to be constant for each pulse by the switching element, the AC power supply current Is the same as the AC power supply voltage and has the same phase, and the ripple superimposed on the DC output voltage can be remarkably reduced, and the choke coil and the capacitor are also downsized.

[0027]

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of the first embodiment of the present invention. In the embodiment shown in FIG. 1, a step-down type high power factor converter is taken as an example, and parts having the same mechanism as those in FIG. 23 are designated by the same reference numerals. The configuration of the present embodiment includes a rectifier circuit 2 that constitutes a rectifier circuit, a first switching element 31 that corresponds to the switching element 3 of FIG. 23 that constitutes a switching circuit connected to the output of the rectifier circuit 2, and FIG.
The diode 41 corresponding to the diode 4 of No. 3 and the first corresponding to the choke coil 5 of FIG.
Of the choke coil 51 of FIG. 23 and the first capacitor 61 corresponding to the capacitor 6 of FIG.
3, the same circuit 45, the second choke coil 52, a circuit including the second capacitor 62 charged through the choke coil 52, and a capacitor 6 to form a charging voltage application circuit.
The first choke coil 5 is controlled by controlling the electric power stored in 2.
1 has a circuit in which the second switching element 32 and the diodes 42 and 44 are connected to each other. In addition,
The diodes 42 and 44 are reverse current element diodes.

The high power factor converter of FIG.
A first voltage detector 9A for outputting a first detection voltage V31 corresponding to the current flowing through the switching element 31 of
A second voltage detector 9B for outputting a second detection voltage V51 corresponding to the current flowing through the choke coil 51 of
A control circuit 10 for controlling the first and second switching elements 31 and 32 by receiving each output and an AC input voltage
Is provided.

Further, the control circuit 10 includes an oscillator 8 and an absolute value circuit 11 for converting the AC input voltage VAC into an absolute value VACR.
An integrating circuit 12 for integrating the first detection voltage V31 by the first voltage detector 9A into a pulse area modulation signal VPS and resetting it by a reset signal R output from the oscillator 8; and a second capacitor 62. Of the first reference voltage VREF1 by differentially amplifying the voltage V62 and the first reference voltage VREF1.
The first error amplifier 13 for obtaining ER1 and the first error voltage V
A multiplier 14 that multiplies ER1 and the absolute value VACR to obtain a multiplication signal VML, and a first PWM modulation that controls the operation of the first switching element 31 by comparing the multiplication signal VML and the pulse area modulation signal VPS. First comparison circuit 1 for obtaining signal VPWM1
5, the second error amplifier 16 for differentially amplifying the voltage V61 of the first capacitor 61 and the second reference voltage VREF2 to obtain the second error voltage VER2, the second error voltage VER2 and the second error voltage VER2.
Second detection voltage V generated by the voltage detector 9B of
A third error amplifier 17 that differentially amplifies 51 and a third error voltage VER3 and a comparison signal VCO that compares the third error voltage VER3 with a sawtooth wave S having the same frequency as the reset signal R
The second comparison circuit 18 for obtaining MP, the comparison signal VCOMP and the first
And a logic circuit 19 for obtaining a second PWM modulation signal VPWM2 for controlling the operation of the second switching element 32 based on the first PWM modulation signal VPWM1 applied to the switching element 31.

Next, the operation of this embodiment will be described by classifying it into different operation modes corresponding to the combination of the operation states of the first switching element 31 and the second switching element 32.

(A) Operation Mode 1 This is an operation mode when the first switching element 31 is on and the second switching element 32 is off.
In this case, one DC terminal t1 of the rectifier circuit 2 → first switching element 31 → diode 43 → second choke coil 52 → second capacitor 62 → first voltage detector 9A → the other side of the rectifier circuit 2 Current flows through the path of the DC terminal t2 of the rectifier circuit 2 in the second choke coil 52.
The voltage obtained by subtracting the voltage V62 of the second capacitor 62 from the DC output voltage is applied.

As the current flowing through the second choke coil 52 increases, the DC terminal t1 of the rectifier circuit 2 → the first switching element 31 → the diode 41 → the first choke coil 51 → the first capacitor 61 and the load 20. → second voltage detector 9B → first voltage detector 9A → current flows through the path of the other DC terminal t2 of the rectifier circuit 2, and the DC output voltage of the rectifier circuit 2 is the voltage V61 of the first capacitor 61.
When it is larger, the current flowing through the first choke coil 51 increases. When the DC output voltage of the rectifier circuit 2 is smaller than the voltage V61 of the first capacitor 61, the current flowing through the first choke coil 51 decreases.

(B) Operation Mode 2 This is an operation mode when the first switching element 31 is off and the second switching element 32 is on.
In this case, the voltage V62 of the second capacitor 62 is applied to the second choke coil 52 in the opposite polarity, and the second choke coil 52 → the second capacitor 62 → the diode 45.
→ Current flows back in the path of the second choke coil 52,
The current flowing through the second choke coil 52 decreases.

At the same time, the second capacitor 62 → second switching element 32 → diode 44 → first choke coil 51 → first capacitor 61 and load 20 → second
The current flows in the path of the voltage detector 9B → the second capacitor 62, and the current flowing in the first choke coil 51 increases.

(C) Operation Mode 3 This is an operation mode when the first switching element 31 is off and the second switching element 32 is also off.
In this case, the voltage V61 of the first capacitor 61 is applied to the first choke coil 51 in reverse polarity, and the first choke coil 51 → first capacitor 61 and load 20 →
The current flows back through the path of the second voltage detector 9B → diode 41, and the current flowing through the first choke coil 51 decreases.

In each of the operation modes (a) to (c) described above, the first and second switching elements 31 and 32 are turned on and off at a frequency sufficiently higher than the frequency of the AC input power supply 1. Moreover, since the second choke coil 52 has a small inductance, the DC output voltage of the rectifier circuit 2 is larger than the voltage of the second capacitor 62 in the second choke coil 52, as shown in FIG. The current flows only during the period, that is, the period when the instantaneous value of the AC input voltage is large, and the DC output voltage of the rectifier circuit 2 is the second capacitor 6
In the period of being smaller than the voltage of 2, that is, in the vicinity of the zero cross of the AC input voltage, a current does not flow, and the waveform becomes a triangular wave having an envelope of a frequency twice the frequency of the AC input power source.

Next, the operation of the control circuit 10 of the high power factor converter circuit of the present invention will be described. The integrating circuit 12 is
It has a function of inputting the first detection voltage V31 provided from the first voltage detector 9A composed of a shunt, outputting the pulse area modulation signal VPS, and supplying it to the first comparison circuit 15, and the AC input A reset signal R provided from an oscillator 8 which outputs a signal having a frequency sufficiently higher than the frequency of the power supply 1.
As a result, the pulse waveform train having an envelope with a frequency twice that of the AC input power source 1 is obtained as shown in FIG.

On the other hand, the first error amplifier 13 differentially amplifies the voltage V62 of the second capacitor 62 and the first reference voltage VREF1 and outputs the first error voltage VER1. The error voltage VER1 is multiplied by the absolute value VACR of the AC input voltage VAC provided from the absolute value circuit 11 in the multiplier 14 to become the multiplication signal VML. This multiplication signal VML has a waveform of the absolute value of a sine wave as shown in FIG.

The pulse area modulation signal VPS and the multiplication signal VML are input to the first comparison circuit 15, and the first switching element 31 is turned on in the section where the pulse area modulation signal VPS is larger than the multiplication signal VML. The first PWM modulation signal VPWM1 is obtained.

Since the first switching element 31 is PWM-controlled in this way, the AC input current is shaped into a sine wave in phase with the AC input voltage, and the voltage V62 of the second capacitor 62 is controlled to a constant voltage. To be done.

The second error amplifier 16 is for differentially amplifying the voltage V61 of the first capacitor 61 and the second reference voltage VREF2 to obtain the second error voltage VER2.
The second error voltage VER2 and the second detection voltage V51 from the second voltage detector 9B including a shunt are the third
Is differentially amplified by the error amplifier 17 to obtain the third error voltage VER3.

The third error voltage VER3 is input to the second comparison circuit 18 and compared with the sawtooth wave S having the same frequency as the reset signal R, and the sawtooth wave S is supplied to the third error voltage VER3.
The comparison signal VCOMP that outputs a pulse in a larger section is obtained.

First PWM modulation signal VPWM1 and comparison signal V
COMP is input to the logic circuit 19 and turns on the second switching element 32 when the comparison signal VCOMP is at H level and the first PWM modulation signal VPWM1 is at L level as shown in FIG. 2 PWM modulation signal VPWM2 is obtained.

In this way, since the second switching element 32 is PWM-controlled, the voltage V61 of the first capacitor 61 is constant-voltage controlled, and therefore the inductance of the first choke coil 51 and the first capacitor 61 are controlled. Even if the capacitance of 61 is small, almost no ripple voltage is included in the voltage V61.

Although the high frequency filter 7 is inserted between the AC input power source 1 and the AC input side of the rectifier circuit 2, it is inserted between one DC terminal t1 of the rectifier circuit 2 and the other DC terminal t2. Obviously good. Moreover, when a transformer for insulation is inserted between the AC input power supply 1 and the high frequency filter 7, it is also clear that the leakage inductance can be used to omit the choke coil of the high frequency filter.

FIG. 5 shows a circuit of the second embodiment. Parts having the same functions as those in the embodiment of FIG. 1 are given the same numbers. In comparison with the embodiment of FIG. 1, a high frequency transformer 21 for converting a switching voltage, a rectifying diode 46 and a resetting diode 47 are added to insulate the input and output from each other so that the input side is not affected by the output side. However, the same operation can be performed by a control circuit similar to the embodiment of FIG. 1 (not shown).

FIG. 6 shows a circuit of the third embodiment. Parts having the same functions as those of the embodiment shown in FIG. 1 and parts having the same functions as those shown in FIG. 5 are designated by the same reference numerals. By adding a circuit composed of the choke coil 52, the switching element 32, the diodes 43, the same 44, the same 45, and the capacitor 62 to the secondary side of the high frequency transformer 21A of the switching power supply circuit, a circuit similar to that of the embodiment of FIG. The same operation can be performed by the control circuit. Even with this circuit, the input and output can be isolated by the high frequency transformer.

FIG. 7 shows a circuit of the fourth embodiment. Parts having the same functions as those of the embodiment shown in FIG. 1 and parts having the same functions as those shown in FIGS. 5 and 6 are designated by the same reference numerals. A choke coil 52 is provided on the secondary side of the high frequency transformer 21B of the push-pull type switching power supply circuit including the switching element 31A.
By adding a circuit including the diodes 42, 44, 45, and the capacitor 62, the same operation can be performed by a control circuit (not shown) similar to that of FIG. With this circuit, the input and output can be isolated by a high frequency transformer.

FIG. 8 shows a circuit of the fifth embodiment. Book 5
In this embodiment, the present invention is applied to a step-up type, and the parts having the same functions as those of the embodiment of FIG. In this circuit, the first switching element 31 is shown so that the AC input current is a sine wave, and the second switching element 32 is shown so that the voltage of the first capacitor 61, that is, the DC output voltage is a constant voltage. The same effect can be obtained by controlling with a control circuit similar to that of the embodiment of FIG.

9 and 10 show the circuits of the sixth and seventh embodiments. FIG. 1 shows an example in which the present invention is applied to a buck-boost type.
The parts having the same functions as those in the above embodiment and the parts having the same functions as those in FIG. In this circuit, the first switching element 31 is shown so that the AC input current is a sine wave, and the second switching element 32 is shown so that the voltage of the first capacitor 61, that is, the DC output voltage is a constant voltage. The same effect can be obtained by controlling with a control circuit similar to that of the embodiment of FIG.

Note that, in FIGS. 8, 9 and 10, it is also easy to interpose an insulating transformer for insulating the input and output sides between the AC input power source 1 and the rectifier circuit 2.

FIG. 11 is a circuit diagram showing the structure of the eighth embodiment of the present invention. The embodiment shown in FIG. 11 is an example of a step-down type high power factor converter, and parts having the same functions as those in FIG. 23 are designated by the same reference numerals. The configuration of this embodiment includes a rectifier circuit 2, a first switching element 31 and a third switching element 33 connected to the DC side of the rectifier circuit 2,
The load of the load 2 by smoothing the output of the first switching element
An output circuit that connects the first choke coil 51 and the first capacitor 61 to form an output filter to supply 0, and the third switching element to charge the output of the third switching element 33. 33 and a charging circuit including a series connection of a second capacitor 62 and a second choke coil 52 arranged between the output circuit, and a charging voltage of the second capacitor 62 to the output circuit. Power to be supplied to the output circuit by alternately sending the charging voltage applying circuit applied via the switching element 32, the output of the first switching element 31 and the output of the charging voltage applying circuit to the output circuit. Of the first and second switching elements 31, 3 so that the sum of
A control circuit 10 for controlling the control unit 2 is provided. Further, in this embodiment, the diode 41 corresponding to the diode 4 in FIG. 23, the reverse current blocking diodes 42 and 44, the diode 43 provided in the second switching circuit, and the charging circuit 50.
It has a diode 45 provided in the.

Further, in the high power factor converter of FIG. 11, the conduction voltage of the first voltage detector 9A which outputs the first detection voltage V31 corresponding to the DC current of the rectifier circuit 2 and the conduction current of the third switching element 33. A third voltage detector 9C for outputting a third detection voltage V33 corresponding to the first choke coil 5
A second voltage detector 9B that outputs a second detection voltage V51 corresponding to the conduction current of 1 is provided, and each detection voltage and an AC input voltage, a charging voltage of the second capacitor 62, and a DC output by the output circuit. The voltage and the voltage are input to the control circuit 10, and the first, second and third switching elements 31, 32 and 3 are input.
A first, a second and a third pulse width modulated signal controlling 3 are created.

The control circuit 10 includes an oscillator 8 which outputs a sawtooth wave having a frequency sufficiently higher than the frequency of the AC power source 1, and an output V21 of an absolute value circuit 11 which converts the AC input voltage VAC into an absolute value VACR. A first multiplier 14A that multiplies a third error voltage VER3 determined as described later, and a first high-frequency filter 104 that averages the first detection voltage V31.
A, the output voltage of the first high frequency filter 104A and the first
A first differential amplifier 101 that differentially amplifies the output voltage of the multiplier 14A and a first comparison circuit 15 that compares the output voltage of the first differential amplifier 101 with a sawtooth wave,
The output voltage of the first comparison circuit 15 becomes the first PWM modulation signal VPWM1 that controls the operation of the first switching element 31.

Further, the control circuit 10 is provided with the DC voltage V2 obtained by the voltage dividing circuit 19 from the output of the absolute value circuit 11.
The subtracter 106 for subtracting the divided voltage value of the first error amplifier 1 and the first error amplifier 1 for obtaining the first error voltage VER1 by comparing and amplifying the charging voltage V62 of the second capacitor 62 and the first reference voltage VREF1.
3, a second multiplier 14B that multiplies the first error voltage VER1 by the output voltage of the subtractor 106, a second high frequency filter 104B that amplifies the second detection voltage V33, and a second high frequency filter 104B. A second differential amplifier 102 that differentially amplifies the output voltage and the output voltage of the second multiplier 14B,
A third comparator 103 for comparing the output voltage of the second differential amplifier 102 with the sawtooth wave, and the third comparator 10
The output voltage of 3 becomes the third PWM modulation signal VPWM3 that controls the operation of the third switching element 33.

Further, the control circuit 10 outputs the second error amplifier 16 which obtains the second error voltage VER2 by comparing and amplifying the DC output voltage V61 and the second reference voltage VREF2.
A third error amplifier 17 for differentially amplifying a second detection voltage V51 generated by the second voltage detector 9B to obtain a third error voltage VER3, a third error voltage VER3 and a sawtooth wave. And a second comparator 18 with which
The output voltage of the comparator 18 of the second switching element 32
It becomes the second PWM modulation signal VPWM2 for controlling the operation of.

By inputting the output voltage VER3 of the third error amplifier 17 to the first multiplier 14, the output power of the first switching circuit is appropriately proportional to the output power of the second switching circuit. It can be set to any value.

In each operation described above, the first, second and third switching elements 31, 32 and 33 are turned on and off at a frequency sufficiently higher than the frequency of the AC power supply 1.
In addition to reducing the inductance of the second choke coil 52,
The output voltage VACR of the absolute value circuit 11 as shown in (a)
13A, the third switching element 33 is subtracted from the output voltage VACR of the absolute value circuit as shown in FIG. 13A by the subtractor 106 of the divided voltage value of the DC voltage VACR obtained by the voltage dividing circuit 19. When controlled in accordance with the output voltage obtained by the subtraction in step 1, a current as shown in FIG. 12B flows through the first switching element 31 and a current as shown in FIG.
3 (b), a current flows through the second choke coil 52 at twice the frequency of the AC power supply 1 during the period when the instantaneous value of the AC power supply voltage is large as shown in FIG. 14 (a). A current having a sinusoidal waveform having an envelope of frequency f flows, and a current having a waveform as shown in FIG. 14B flows through the first choke coil 51.

Next, the operation of the control circuit 10 of the high power factor converter shown in FIG. 11 will be described.

That is, the output voltage VACR of the absolute value circuit 11 is converted to the third error voltage VER3 by the first multiplier 14A.
And a first detection voltage V31 corresponding to the output current of the rectifier circuit 2 is obtained by the first high-frequency filter 104A, and the first multiplier 14A is obtained by the first differential amplifier 101.
Output voltage of the first high frequency filter 104A is differentially amplified, and a first PWM modulation signal VPWM1 is obtained by comparing the output voltage of the first differential amplifier 101 with a sawtooth wave. Therefore, the output power of the first switching element 31 can be set to an appropriate value proportional to the output power of the second switching element 32.

Further, the absolute value circuit 1 is controlled by the subtractor 106.
The divided voltage value of the DC voltage VACR is subtracted from the output voltage VACR of 1, and the first error amplifier 13 compares and amplifies the charging voltage V62 of the second capacitor and the first reference voltage VER1 to obtain the first error. The voltage VER1 is obtained, and the second multiplier 14B outputs the first error voltage VER to the output voltage of the subtractor 106.
Multiply by 1 and the second high frequency filter 104B
A second detection voltage V98 corresponding to the conduction current of the switching element of the second differential amplifier 102, and the second detection voltage V98 is obtained by the second differential amplifier 102.
Differentially amplify the output voltage of the multiplier 14B and the output voltage of the second high frequency filter 104B, and the third PWM modulation signal VPWM3 compares the output voltage of the second differential amplifier 102 with the sawtooth wave. Therefore, the charging voltage V of the capacitor is turned on and off by turning on and off the third switching element 33.
62 is a constant voltage corresponding to the first reference voltage VER1. At the same time, the current waveform of the second reactor 52 can be controlled to the waveform shown in FIG.

The second error amplifier 16 compares and amplifies the DC output voltage V61 with the second reference voltage VER2 to obtain the second error voltage VER2, and the second voltage detector 9B causes the first choke to operate. A third detection voltage V51 corresponding to the conduction current of the coil 51 is generated, and both are amplified by the differential amplifier 17 to obtain a third error voltage VER3. The second PWM modulation signal VPWM2 is the second error voltage. Since VER2 is obtained by comparing with the sawtooth wave, the DC output voltage V61 becomes a constant voltage corresponding to the second reference voltage VER2 by turning on and off the second switching element 32.

FIG. 15 is a circuit diagram showing the structure of the ninth embodiment of the present invention, in which parts having the same functions as those in FIG. 11 are designated by the same reference numerals. In the structure of the ninth embodiment, the outputs of the first and third switching elements 31 and 33 are insulated by the high frequency transformer 21, and a rectifying diode 46 and a resetting diode 47 are added.

FIG. 16 is a circuit diagram showing the structure of the tenth embodiment of the present invention, in which parts having the same functions as those in FIGS. 11 and 15 are designated by the same reference numerals. The configuration of the tenth embodiment is such that the first switching element 31 includes 31A and 31B.
And a push-pull method in which the second switching element 32 is 32A and 32B,
The outputs of the first and third switching circuits are insulated by a high frequency transformer 21, and a diode 46 is added to the secondary side of the high frequency transformer 22.

FIG. 17 is a circuit diagram showing the structure of the eleventh embodiment of the present invention, in which parts having the same functions as those in FIGS. 11, 15 and 16 are designated by the same reference numerals. This eleventh
In the configuration of the embodiment, the first switching element 31 includes 31A,
31B, 31C and 31D are full bridge type, and the second switching element 32 is 32A, 32B, 3
2C and 32D are used as a full bridge system, the outputs of the first and third switching elements are insulated by a high frequency transformer 21, and a diode 46 is added to the secondary side of the high frequency transformer 21.

FIGS. 18 and 19 are circuit diagrams showing the configurations of the twelfth and thirteenth embodiments of the present invention, in which parts having the same functions as those in FIGS. 11, 15, 16 and 17 are designated by the same reference numerals. Is attached. In the configurations of the twelfth and thirteenth embodiments, the diode 41 of FIG. 11 is used as the choke coil 53,
A diode 49 and a capacitor 63 are connected in series with the choke coil 53 in series, and the configuration of the tenth embodiment is modified into a buck-boost type. FIG. 18 is a diagram of the input / output non-insulation system, and FIG. 19 is a diagram of the input / output isolation system in which the transformer 21 is used instead of the choke coil 53.

20 and 21 are circuit diagrams showing the configurations of the fourteenth and fifteenth embodiments of the present invention, in which parts having the same functions as those in FIGS. 11 and 15 to 19 are designated by the same reference numerals. ing. In the constructions of the fourteenth and fifteenth embodiments, the first switching circuit includes a choke coil 54 and a first switching element 31 connected in series, a diode 42 and a first capacitor 61 in parallel with the first switching element 31. And the second switching circuit 302 is connected in series with the choke coil 55 and the second switching element 32, and with the diode 43 in parallel with the second switching element 32 and the second capacitor 62. The charging voltage application circuit is connected in series with the choke coil 56 and the third switching element 33, and the third switching element 3 is connected.
The diode 44 in parallel with 3 and the first capacitor 61 are connected in series, and the configuration of the ninth embodiment is modified to a boost type. FIG. 20 is a diagram of the input / output non-insulation method.
FIG. 1 is a diagram of an input / output insulation method using a transformer 21.

FIG. 22 shows that all the components inserted in the plus DC line from the circuit of FIG. 11 have been moved to the minus side. With such a circuit configuration, it is possible to support a system in which the positive side is grounded.

[0070]

As described above, according to the present invention, it is possible to simultaneously reduce the harmonics contained in the AC power supply current and the ripple of the DC output.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a high power factor converter according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of a current flowing through a second choke coil 52 of FIG. 1 and a related voltage.

3 is a pulse area modulation signal VPS of the control circuit 10 of FIG.
FIG. 7 is a waveform diagram of a multiplication signal VML.

4 is a first PWM modulation signal VPWM of the control circuit of FIG.
3 is a waveform diagram of the first and second PWM modulation signals VPWM2 and the comparison signal VCOMP. FIG.

FIG. 5 is a circuit diagram of a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a third embodiment of the present invention.

FIG. 7 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram of a fifth embodiment of the present invention.

FIG. 9 is a circuit diagram of a sixth embodiment of the present invention.

FIG. 10 is a circuit diagram of a seventh embodiment of the present invention.

FIG. 11 is a circuit diagram of an eighth embodiment of the present invention.

12 is a control waveform diagram of the first switching element of the high power factor converter of FIG. 11. FIG.

13 is a control waveform diagram of a third switching element of the high power factor converter of FIG.

FIG. 14 is a current waveform diagram of the first and second choke coils of the high power factor converter of FIG.

FIG. 15 is a circuit diagram of a ninth embodiment of the present invention.

FIG. 16 is a circuit diagram of a tenth embodiment of the present invention.

FIG. 17 is a circuit diagram of an eleventh embodiment of the present invention.

FIG. 18 is a circuit diagram of a twelfth embodiment of the present invention.

FIG. 19 is a circuit diagram of a thirteenth embodiment of the present invention.

FIG. 20 is a circuit diagram of a fourteenth embodiment of the present invention.

FIG. 21 is a circuit diagram of a fifteenth embodiment of the present invention.

FIG. 22 is a circuit diagram of a sixteenth embodiment of the present invention.

FIG. 23 is a circuit diagram of a conventional step-down high power factor converter circuit.

24 is a waveform diagram of a current flowing through the switching element 3 of FIG.

25 is a waveform diagram of a current flowing on the AC side of the rectifier circuit 2 of FIG. 23 and an AC input voltage.

[Explanation of symbols]

 1 AC input power supply 2 Rectifier circuit 3,31A Switching element 4 Diodes 5,53,54,55 Choke coil 6 Capacitor 7 High frequency filter 8 Oscillator 9A First voltage detector 9B Second voltage detector 9C Third voltage detection 10, 100 Control circuit 11 Absolute value circuit 12 Integration circuit 13 First error amplifier 14 Multiplier 15 First comparison circuit 16 Second error amplifier 17 Third error amplifier 18 Second comparison circuit 19 Logic circuit 20 Load 21,21A, 21B High frequency transformer 31 1st switching element 32 2nd switching element 33 3rd switching element 41-49 Diode 51 1st choke coil 52 2nd choke coil 61 1st capacitor 62 2nd Capacitor 101 first differential amplifier 102 second differential Width 103 third comparator circuit 104A, 104B high frequency filter 106 subtractor 107 dividing circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Taiji Tomokuni, 6-6 Josaimachi, Takatsuki-shi, Osaka Prefecture, Yuasa Corporation (72) Inventor, Katsuya Hirachi 6-6, Josaimachi, Takatsuki, Osaka Inside Yuasa Corporation

Claims (10)

[Claims] 1. A step-down, step-up or step-up / down type high power factor converter that improves the input power factor, suppresses harmonics, and reduces ripples in the DC output by using an AC input current as a sine wave. A rectifying circuit for full-wave rectifying a power supply; and a switching circuit for switching and outputting a DC output voltage output from the rectifying circuit by a first switching element driven at a frequency sufficiently higher than the frequency of the AC input power supply. , An output circuit that forms an output filter by connecting a first choke coil and a first capacitor to smooth the output of the switching circuit and supply it to a load, and charges the output of the first switching element. Therefore, a charging circuit including a series connection of a second choke coil and a second capacitor arranged between the first switching element and the output circuit. An electric circuit and a second part included in the charging circuit
A charging voltage applying circuit for applying the charging voltage of the capacitor to the output circuit via a second switching element, and an output of the switching circuit and an output of the charging voltage applying circuit are alternately sent to the output circuit. A control circuit for controlling the first and second switching elements so that the sum of electric power supplied to the output circuit via the first switching element and the second switching element is always constant. A high power factor converter characterized in that 2. A predetermined first pulse width modulation of the first switching element so that the waveform of the AC input current to the rectifier circuit becomes a sine wave and the charging voltage of the second capacitor becomes a constant voltage. The high power factor converter according to claim 1, further comprising a control circuit controlled by a signal. 3. The second switching element is the first switching element.
The switching element is driven so as not to output at the same time as the switching element, and the second switching element is supplied with a predetermined second pulse width modulation signal so that the DC output voltage from the output circuit to be applied to the load becomes a constant voltage. The high power factor converter according to claim 1, further comprising a control circuit for controlling. 4. A first detection voltage obtained by detecting an output current of the first switching element, the AC input power supply, and a reset signal and a sawtooth wave having a frequency sufficiently higher than that of the AC input power supply. Based on a reset signal of an oscillator for outputting the first switching element for controlling the operation of the first switching element so that the AC input current of the full-wave rectifier circuit has a waveform synchronized with the voltage of the AC input power supply. And a second detection voltage obtained by detecting a conduction current of the first choke coil, a charging voltage of the first capacitor, and a sawtooth wave of the oscillator. Power supplied to the load side via the first switching element and power supplied to the load side via the second switching element based on the first pulse width modulation signal. The high power factor converter according to claim 1, further comprising a control circuit that outputs the second pulse width modulation signal that controls the operation of the second switching element so that the sum is constant for each pulse. . 5. A high frequency transformer for converting a switching voltage formed by the first and second switching elements or an insulating transformer for separating an input side and an output side is provided. 3 or 4
High power factor converter as described. 6. A step-down, step-up or step-up / down type high power factor converter that secures input power factor improvement, harmonic suppression, and DC output ripple reduction by using an AC power supply current as a sine wave. A full-wave rectifying circuit, a first switching circuit that outputs a direct-current output voltage output from the rectifying circuit by switching with a first switching element driven at a frequency sufficiently higher than the frequency of an alternating-current power supply, and And an output circuit for forming an output filter by connecting the first choke coil and the first capacitor in order to smooth the outputs of the switching circuit of No. 3 and the first switching circuit and supply them to the load. A second choke coil disposed between the third switching circuit and the output circuit to charge the output of the second choke coil and the second choke coil.
Of a charging circuit including a series connection with the capacitor and a charging voltage of a second capacitor included in the charging circuit to the output circuit via a second switching element, and the first switching circuit. A control circuit for controlling the first and second switching elements so that the output and the output of the charging voltage application circuit are alternately sent to the output circuit so that the sum of the electric power supplied to the output circuit is always constant. And a high power factor converter. 7. The first and third control circuits are configured such that the waveform of the AC power supply current to the rectifier circuit is a sine wave and the charging voltage of the second capacitor is a constant voltage.
7. The high power factor converter according to claim 6, further comprising a function of controlling the switching element of 1. by the first and third pulse width modulation signals. 8. The control circuit is driven so that the second switching element and the first switching element do not output simultaneously and the DC output voltage from the output circuit to be applied to the load is a constant voltage. To be the second
2. The high power factor converter according to claim 1, further comprising a function of controlling the switching element of 1. by the second pulse width modulation signal. 9. The control circuit generates a first detection voltage obtained by detecting a DC current of a rectifying circuit, a DC voltage of the rectifying circuit, and a sawtooth wave having a frequency sufficiently higher than the frequency of the AC power supply. Based on the output signal of the oscillator, the first pulse width modulation signal that outputs a waveform in which the alternating current of the rectifier circuit is synchronized with the alternating current power supply voltage is output, and the first detection voltage and the second detection voltage are output. The AC current of the rectifier circuit is synchronized with the AC power supply voltage based on the charging voltage of the capacitor, the third detection voltage obtained by detecting the conduction current of the third switching element, and the sawtooth wave. And outputting a third pulse width modulation signal having a waveform as described above, detecting a DC output voltage from the output circuit, and a conduction current of the first choke coil; Based on sawtooth and , The second pulse for making the sum of the power supplied to the load via the first switching element and the power supplied to the load via the second switching element constant for each pulse 9. The high power factor converter according to claim 7, further comprising a function of outputting a width modulation signal. 10. A high frequency transformer for converting the output of the first switching circuit and the output of the charging voltage applying circuit into an output circuit or between the first switching circuit and the charging voltage applying circuit and the output circuit. 9. An insulating transformer for insulating is provided.
Or the high power factor converter described in 9.