JPH06303774A - Rectification and smoothing circuit - Google Patents

Abstract

PURPOSE:To improve the power factor of a power supply and to reduce high harmonic components in a rectification smoothing circuit for converting an AC power supply to a DC power supply in a room air-conditioner, etc., incorporating an inverter motor. CONSTITUTION:A series resonance circuit consisting of a first capacitor 7, a rectification element 8, a first choke coil 5, and a second capacitor 6 and a second choke coil 4 electromagnetically couple to the first choke coil 5 are provided between a rectification diode bridge 3 and a smoothing capacitor 9 to effectively rectify AC current, and at the same time electromagnetically coupled choke coils 11 and 12 are provided between an AC power supply 1 and a rectification diode bridge and a high power factor is maintained by bringing AC input current closer to a sinusoidal wave, thus reducing the high harmonic components of current.

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 rectifying / smoothing circuit for improving a power source power factor of a device for converting an AC power source into a DC power source in a room air conditioner having an inverter motor built therein.

[0002]

2. Description of the Related Art FIG. 5 shows a basic circuit of a conventional rectifying and smoothing circuit,
FIG. 6 shows the power supply frequency of the rectifying and smoothing circuit in the basic circuit of FIG.
AC input current waveform example I at several 60 Hz (Hertz)₂
(T) and voltage waveform example V₂(T), FIG. 7 shows the AC input of FIG.
The frequency spectrum of an example of a force current waveform is shown. 8 is the same
The conventional high power factor rectification smoothing circuit, FIG. 9 is the smoothing circuit of FIG.
AC input current waveform example I at a power supply frequency of 60 Hz₃
(T) and voltage waveform example V ₃(T), FIG. 10 is the alternating current of FIG.
The frequency spectrum of the input current waveform example
There is. In FIG. 5, the AC input current is the rectifier diode block.
Be rectified by the ridge 3 and smoothed by the smoothing capacitor 9.
Is converted to DC by and. As shown in FIG.
In the circuit of, the smoothing co
Since the input current flows through the capacitor 9, the power factor decreases,
In addition, as shown in Fig. 7, the rectifying and smoothing circuit contains many harmonic components.
There was a problem as a road.

Conventionally, in order to improve the power factor, as shown in FIG. 8, a choke coil (L ₆ ) 13 and a capacitor (C ₃ ) 14 are connected in series between the rectifying diode bridge 3 and the smoothing capacitor 9. The parallel resonant circuit composed of was connected. Since the current flowing in the parallel resonant circuit vibrates at a frequency higher than the power supply frequency, the AC input current has a distorted waveform as shown in the current waveform example I ₃ (t) in FIG.
Compared to the circuit shown in FIG. 5, there was a harmonic component, but it was possible to improve the power factor.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the power supply harmonic current (integral multiple component of commercial frequency), which is a problem of the conventional high power factor rectifying and smoothing circuit. In the conventional circuit, there is a problem that the power factor is deteriorated when a circuit constant that reduces the power supply harmonic current is selected, but the circuit of the present invention makes it possible to maintain a high power factor and reduce the power supply harmonics. The purpose is to make them.

[0005]

In order to solve the above-mentioned problems, the present invention provides a capacitor input type rectifying / smoothing circuit for converting an AC power source into a direct current by a rectifying diode bridge and a smoothing capacitor. A first capacitor connected in parallel to the smoothing capacitor between the rectifying diode bridge and the smoothing capacitor; a rectifying element connected in series between the first capacitor and the smoothing capacitor; A series circuit including a first choke coil and a second capacitor connected in parallel to the first capacitor between the rectifying diode bridge and the first capacitor, the series circuit, and the first capacitor.
Second choke coil connected in series with the first capacitor and electromagnetically coupled with the first choke coil, and electromagnetically coupled with each other in series connected between the AC power supply and the rectifying diode bridge. The present invention provides a rectifying / smoothing circuit comprising the fourth choke coil and the fifth choke coil described above.

According to a second aspect of the present invention, in a rectifying / smoothing circuit of a capacitor input type for converting an AC power source into a direct current by a rectifying diode bridge and a smoothing capacitor, the smoothing capacitor is provided between the rectifying diode bridge and the smoothing capacitor. A first capacitor connected in parallel with the first rectifier, a rectifying element connected in series between the first capacitor and the smoothing capacitor, and a first rectifier between the rectifying diode bridge and the first capacitor. A series circuit composed of a first choke coil and a second capacitor connected in parallel to one capacitor, and a series circuit connected between the series circuit and the first capacitor and the first circuit. A second choke coil electromagnetically coupled to the choke coil, and a series connection between the AC power source and the rectifying diode bridge. It is intended to provide a rectifying smoothing circuit, characterized in comprising; and a third choke coils.

[0007]

In the rectifying / smoothing circuit according to the first aspect of the present invention, the series resonance circuit including the first and second choke coils and the capacitor resonates with a circuit constant for increasing the power factor at the AC power supply frequency, and the first capacitor, A fourth capacitor, which is charged and discharged with the second capacitor, more effectively rectifies the AC component of the AC power source by the rectifying element and the smoothing capacitor, and electromagnetically engaged with each other between the AC power source and the rectifying diode bridge. By providing the fifth choke coil, mutual inductance due to electromagnetic coupling is effectively acted, and the AC input current is approximated to a sine wave to maintain a high power factor.

According to another aspect of the rectifying circuit of the present invention, the AC power source and the rectifying diode bridge are electromagnetically coupled to each other.
By providing the third choke coil instead of the choke coil of No. 3, the AC input current is made to approximate to a sine wave to maintain a high power factor, and the harmonic current component is reduced and the high power factor is maintained at the same time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the embodiments shown in the drawings. FIG. 1 shows a first embodiment of the high power factor rectifying / smoothing circuit of the present invention, FIG. 2 shows a second embodiment of the high power factor rectifying / smoothing circuit of the present invention, and FIG. An AC input current waveform example I ₁ (t) and a voltage waveform example V ₁ (t) at a power supply frequency of 60 Hz (hertz) of the smoothing circuit are shown in FIG. 4, and a frequency spectrum of the AC input current waveform example in FIG. 3 is shown.

In FIG. 1, the resonance circuit is composed of an electromagnetically coupled choke coil (L ₁ ) 5, choke coil (L ₂ ) 4, capacitor (C ₁ ) 7 and capacitor (C ₂ ) 6. In this resonance circuit, a series resonance circuit is connected in parallel, and two choke coils (L ₁ ) 5 and (L ₂ ) 4 are electromagnetically coupled, and approximately, f ₁ = 1 / [2π√ [ (L ₁ + M ₁ ) C ₂ ]] f ₂ = 1 / [2π√ [(L ₂ + M ₁ ) C ₁ ]] where f ₁ is on the choke coil (L ₁ ) 5 and capacitor (C ₂ ) 6 side Resonance frequency, f ₂ is choke coil (L
₂ ) 4, resonance frequency of capacitor (C ₁ ) 7 side, M ₁ is choke coil (L ₁ ) 5, choke coil (L ₂ )
4 is the mutual inductance between them. In this resonant circuit, the resonance frequency f ₁ is within the range of 1.5 times to 53.5 times the AC power supply frequency effectively with the effect of electromagnetic coupling, and the circuit constant (the AC power supply frequency 2.
A resonance frequency of about 5 times) is selected. Further, by setting the capacity of the capacitor (C ₁ ) 7 to be the capacity of the capacitor (C ₂ ) 6 or more, it becomes easy for current to flow from the capacitor (C ₁ ) 7 to the capacitor (C ₂ ) 6. Rectifying element 8
Has a function of preventing current from flowing from the smoothing capacitor 9 to the capacitor (C ₂ ) 6 side at the same time when current flows from the capacitor (C ₁ ) 7 to the capacitor (C ₂ ) 6 side, and smoothes the AC component. Rectify to and convert to direct current.

Further, an AC input current is approximated to a sine wave by an electromagnetically coupled choke coil (L ₄ ) 11 and choke coil (L ₅ ) 12 connected in series between the AC power source 1 and the rectifying diode bridge 3. , An example of an AC input current waveform I ₁ (t) as shown in FIG.

The choke coil (L
₁ ) When the current flowing through 5 and the capacitor (C ₂ ) 6 oscillates, the capacitor (C ₁ ) 7 is discharged in about the first half of the 1/2 cycle of the AC input current waveform, and together with the AC input current, the capacitor (C ₁ ) 7 is discharged. Charge (C ₂ ) 6. The capacitor (C ₂ ) 6 is discharged and the capacitor (C ₁ ) 7 is charged together with the AC input current in the latter half of the 1/2 cycle of the AC input current waveform. When the potential of the capacitor (C ₁ ) 7 becomes higher than the potential of the smoothing capacitor 9 by charging, the smoothing capacitor 9 is charged through the rectifying element 8. By such an action, the alternating current is rectified more effectively than the conventional one.

The AC input current waveform example I ₁ (t) of the circuit of the first embodiment shown in FIG. 3 has less distortion than the conventional AC input current waveform example I ₃ (t) shown in FIG. As shown in the frequency spectrum of the AC input current waveform example of the circuit of the first embodiment shown in FIG. 4, the frequency component near the 1.5th order, which is high in the frequency spectrum of the AC input current waveform example of the conventional circuit shown in FIG. Will be greatly reduced.

The circuit diagram of the second embodiment shown in FIG.
1 compared with the first embodiment, the AC power supply 1
Electromagnetically coupled between the rectifier diode bridge 3 and
Joke coil (L_Four) 11, choke coil (L_Five) 1
2 is provided so that the AC input current approaches a sine wave.
However, in the second embodiment, two electromagnetically coupled chos are used.
Choke coil 2 only on one side instead of the coil coil
Is the same as that of the first embodiment.
is there. In the second embodiment, the choke coil (L ₃) Of 2
The inductance is higher than that of the electromagnetically coupled one in the first embodiment.
According to the comparison, the first embodiment has a mutual induction by electromagnetic coupling.
It is more effective because the chest can act and make it larger
Is possible, but the second embodiment is more cost effective.
Can be cheaper. The operation and effect of the second embodiment is the first embodiment.
The description is omitted because it is similar to the example.

[0015]

As described above in detail, in the present invention, the power factor of the AC input of the rectifying / smoothing circuit is improved, and the current utilization efficiency can be improved. Further, since the power supply harmonic current superimposed on the AC input current of the device is reduced, AC voltage distortion can be reduced, and the AC input current can be rectified and smoothed more effectively than before, and The influence on the device itself and other devices can be eliminated, and the reliability of the device can be improved.

[Brief description of drawings]

FIG. 1 is a diagram of a rectifying / smoothing circuit according to a first embodiment of the present invention.

FIG. 2 is a diagram of a rectifying / smoothing circuit according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an example of AC input current and voltage waveforms of the rectifying and smoothing circuit in FIG.

4 is a diagram of a frequency spectrum of an example of an AC input current waveform in FIG.

FIG. 5 is a basic circuit diagram of a conventional rectifying / smoothing circuit.

FIG. 6 is a diagram showing an example of AC input current and voltage waveforms of the rectifying / smoothing circuit in FIG.

7 is a diagram of a frequency spectrum of an AC input current waveform example in FIG.

FIG. 8 is a diagram of a conventional rectifying / smoothing circuit for increasing the power factor.

9 is a diagram showing an example of AC input current and voltage waveforms of the rectifying and smoothing circuit in FIG.

10 is a diagram of a frequency spectrum of an AC input current waveform example in FIG. 9.

[Explanation of symbols]

1 AC power supply 2 Choke coil (L ₃ ) 3 Rectifier diode bridge 4 Choke coil (L ₂ ) 5 Choke coil (L ₁ ) 6 Capacitor (C ₂ ) 7 Capacitor (C ₁ ) 8 Rectifier element 11 Choke coil (L ₄ ) 12 choke coil (L ₅ )

[Procedure amendment]

[Submission date] June 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art FIG. 5 shows a basic circuit of a conventional rectifying and smoothing circuit,
FIG. 6 shows the power supply frequency of the rectifying and smoothing circuit in the basic circuit of FIG.
AC input current waveform example I at several 60 Hz (Hertz)₂
(T) and voltage waveform example V₂(T), FIG. 7 shows the AC input of FIG.
The frequency spectrum of an example of a force current waveform is shown. 8 is the same
The conventional high power factor rectification smoothing circuit, FIG. 9 is the smoothing circuit of FIG.
AC input current waveform example I at a power supply frequency of 60 Hz₃
(T) and voltage waveform example V ₃(T), FIG. 10 is the alternating current of FIG.
The frequency spectrum of the input current waveform example is shown respectively.
There is. In FIG. 5, the AC input current is the rectifier diode block.
Be rectified by the ridge 3 and smoothed by the smoothing capacitor 9.
Is converted to DC by and. As shown in FIG.
In the circuit of, the smoothing co
Since the input current flows through the capacitor 9, the power factor decreases,
In addition, as shown in Fig. 7, the rectifying and smoothing circuit contains many harmonic components.
There was a problem as a road.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

In the rectifying / smoothing circuit according to the first aspect of the present invention, the circuit composed of the first and second choke coils and the first and second capacitors resonates with a circuit constant for increasing the power factor at the AC power supply frequency, and The first capacitor and the second capacitor charge and discharge each other. The rectifying element and the smoothing capacitor rectify and smooth the AC component of the AC power supply. In addition, the fourth and fourth electromagnetically coupled to each other between the AC power supply and the rectifying diode bridge.
By providing the fifth choke coil, mutual inductance due to electromagnetic coupling is effectively acted, the AC input current is approximated to a sine wave, power source harmonics are reduced, and a high power factor is maintained.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

According to another aspect of the rectifying circuit of the present invention, the AC power source and the rectifying diode bridge are electromagnetically coupled to each other.
By providing a third choke coil in place of the choke coil, the AC input current is approximated to a sine wave, power source harmonics are reduced, and a high power factor is maintained.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

In FIG. 1, the resonance circuit is composed of an electromagnetically coupled choke coil (L ₁ ) 5, choke coil (L ₂ ) 4, capacitor (C ₁ ) 7 and capacitor (C ₂ ) 6. In this resonance circuit, a series resonance circuit is connected in parallel, and two choke coils (L ₁ ) 5 and (L ₂ ) 4 are electromagnetically coupled, and approximately, f ₁ = 1 / [2π√ [ (L ₁ + M ₁ ) C ₂ ]] f ₂ = 1 / [2π√ [(L ₂ + M ₁ ) C ₁ ]] where f ₁ is on the choke coil (L ₁ ) 5 and capacitor (C ₂ ) 6 side Resonance frequency, f ₂ is choke coil (L
₂ ) 4, resonance frequency of capacitor (C ₁ ) 7 side, M ₁ is choke coil (L ₁ ) 5, choke coil (L ₂ )
4 is the mutual inductance between them. In this resonant circuit, the resonance frequency f ₁ is within the range of 1.5 times to 3.5 times the AC power supply frequency, effectively accompanied by the effect of electromagnetic coupling. 2.5
Resonance frequency around double). In addition, the capacitor (C
With a capacity of ₁₎ 7 capacitor (C ₂₎ 6 or more, capacitor (C ₁₎ 7 from the capacitor (C ₂₎ 6
Make it easier for current to flow to the side. The rectifying element 8 is configured such that when a current flows from the capacitor (C ₁ ) 7 to the capacitor (C ₂ ) 6, the smoothing capacitor 9 to the capacitor (C ₂ ) simultaneously.
₂ ) It works to prevent current from flowing to the 6 side, rectifies the AC component and converts it to DC.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

The choke coil (L
₁ ) When the current flowing through 5 and the capacitor (C ₂ ) 6 oscillates, the capacitor (C ₁ ) 7 is discharged in about the first half of the 1/2 cycle of the AC input current waveform, and together with the AC input current, the capacitor (C ₁ ) 7 is discharged. Charge (C ₂ ) 6. The capacitor (C ₂ ) 6 is discharged and the capacitor (C ₁ ) 7 is charged together with the AC input current in the latter half of the 1/2 cycle of the AC input current waveform. When the potential of the capacitor (C ₁ ) 7 becomes higher than the potential of the smoothing capacitor 9 by charging, the smoothing capacitor 9 is charged through the rectifying element 8.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The AC input current waveform example I ₁ (t) of the circuit of the first embodiment shown in FIG. 3 has less distortion than the conventional AC input current waveform example I ₃ (t) shown in FIG. In the frequency spectrum of the AC input current waveform example of the conventional circuit shown in FIG. 10, high frequency components near the 15th order are large as shown in the frequency spectrum of the AC input current waveform example of the circuit of the first embodiment shown in FIG. Will be reduced.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The circuit of the second embodiment shown in FIG. 2 is different from the first embodiment of FIG. 1 in that the AC power supply 1 is used in the first embodiment.
Choke coil (L ₄ ) 11 and choke coil (L ₅ ) 12 electromagnetically coupled between the rectifier diode bridge 3 and the rectifier diode bridge 3.
However, in the second embodiment, instead of the two electromagnetically coupled choke coils, the choke coil 2 is provided only on one side of the circuit. Is the same as that of the first embodiment. The choke coil (L ₃ ) 2 of the second embodiment is
Compared with the electromagnetically coupled type of the first embodiment, it is difficult to increase the inductance because mutual inductance due to the electromagnetic coupling does not act, but the second type is costly.
The embodiment can be cheaper. The operation and effect of this second embodiment are the same as those of the first embodiment, so a description thereof will be omitted.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

As described above in detail, in the present invention, the power factor of the AC input of the rectifying / smoothing circuit is improved, and the current utilization efficiency can be improved. In addition, since the power supply harmonic current that is superimposed on the AC input current of the device is reduced, it is possible to reduce AC voltage distortion and eliminate the effect on the device itself and other devices, improving the reliability of the device. Can be measured.

Claims (2)

[Claims] 1. A capacitor input type rectifying / smoothing circuit for converting an AC power supply into a direct current by a rectifying diode bridge and a smoothing capacitor, wherein a first capacitor connected in parallel with the smoothing capacitor between the rectifying diode bridge and the smoothing capacitor. A capacitor and a rectifying element connected in series between the first capacitor and the smoothing capacitor;
A series circuit including a first choke coil and a second capacitor connected in parallel to the first capacitor between the rectifying diode bridge and the first capacitor, the series circuit and the first capacitor. A second choke coil connected in series with the first capacitor and electromagnetically coupled to the first choke coil, and mutually connected in series between the AC power source and the rectifying diode bridge. A rectifying / smoothing circuit comprising a fourth choke coil and a fifth choke coil coupled to each other. 2. A capacitor input type rectifying / smoothing circuit for converting an AC power supply into a direct current by a rectifying diode bridge and a smoothing capacitor, wherein a first capacitor connected in parallel to the smoothing capacitor between the rectifying diode bridge and the smoothing capacitor. A capacitor and a rectifying element connected in series between the first capacitor and the smoothing capacitor;
A series circuit including a first choke coil and a second capacitor connected in parallel to the first capacitor between the rectifying diode bridge and the first capacitor, the series circuit and the first capacitor. A second choke coil that is connected in series with the first capacitor and that is electromagnetically coupled to the first choke coil; and a third choke coil that is connected in series between the AC power supply and the rectifying diode bridge. A rectifying / smoothing circuit comprising a choke coil.