JPH10112979A - Power supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a sufficiently high DC output voltage to a DC load, even in the case a load is increased. SOLUTION: A full-wave rectifier circuit 2 is connected between both terminals of an AC power source 1. A smoothing capacitor C2 and capacitors C11, C12 for voltage multiplier which are connected in series are connected in parallel between the output terminals of the full-wave rectifier circuit 2. A reactor 3 is connected between the full-wave rectifier circuit 2 and the AC power source 1. An LC resonance circuit 4 is connected with the input side or the output side of the full-wave rectifier circuit 2. A switching means MR is connected between the input terminal of the full-wave rectifier circuit 2 which is connected with the terminal with which both the reactor 3 of the AC power source 1 and the LC resonance circuit 4 are not connected and the connection point of the capacitors C11, C12 for voltage multiplier. A control means 5 outputs a control signal for operating the switching means MR when the load is larger than or equal to a predetermined load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power supply device,
More specifically, the present invention relates to a power supply device having a full-wave rectifier circuit, a reactor for improving a power factor and reducing harmonics, and an LC resonance circuit.

[0002]

2. Description of the Related Art In recent years, power semiconductor devices such as inverters and switching power supplies have been widely used. When these devices are driven by a commercial AC power supply, AC-DC conversion is generally performed by a capacitor input type rectifier circuit.
However, in the capacitor input type rectifier circuit, since the input current flows only during a period when the instantaneous value of the AC input voltage is higher than the capacitor voltage, the conduction angle of the input current is narrow and the peak value is very large. For this reason, the input current contains a very large harmonic component, which is becoming a social problem, such as the occurrence of harmonic interference in some devices.

[0003] As a simple power supply device generally used in the past, there is one using a choke input type rectifier circuit shown in FIG. In this power supply device, a full-wave rectifier circuit is connected between terminals of an AC power supply, and a smoothing capacitor is connected between output terminals of the full-wave rectifier circuit via a reactor. When this power supply device is adopted, harmonics contained in the input current can be greatly reduced by the reactor, and an input voltage waveform and an input current waveform as shown in FIG. 2 can be obtained.

Further, as shown in FIG. 3, a full-wave rectifier circuit is connected between terminals of an AC power supply, and a smoothing capacitor is connected between output terminals of the full-wave rectifier circuit via a reactor and a resonance circuit in parallel with each other. A power supply device is proposed. When this power supply device is adopted, the harmonics contained in the input current are greatly reduced by the reactor, and the current conduction angle is advanced to the phase side to improve the power factor. Such input voltage waveform and input current waveform can be obtained.

[0005]

When the power supply device shown in FIG. 1 is employed, it is difficult to increase the power factor because the current conduction angle can be expanded only to the lag phase side. In addition, when the input current increases, the voltage drop due to the reactor increases, so that the DC output voltage decreases as the load increases.

Here, a decrease in the power factor causes an increase in the effective value of the input current, which requires a rectifier circuit having an excessive current capacity.
This leads to an increase in the cost of the entire power supply device. In addition, a decrease in the DC voltage reduces the maximum power that can be supplied to the connected DC load. For example, when a configuration is used in which a DC voltage is supplied to the motor driving inverter by the power supply device, the operating range of the motor driven by the inverter is narrowed.

When the power supply device shown in FIG. 3 is adopted,
The power factor can be increased as compared with the power supply device shown in FIG. 1, and the occurrence of inconvenience due to the decrease in the power factor can be prevented. However, similarly to the power supply device shown in FIG. 1, there is an inconvenience that the DC output voltage is reduced with an increase in load.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and provides a power supply device capable of supplying a sufficiently high DC output voltage to a DC load even when the load increases. It is intended to be.

[0009]

According to a first aspect of the present invention, there is provided a power supply device comprising:
A full-wave rectifier circuit is connected between both terminals of the AC power supply, a smoothing capacitor and a voltage doubler capacitor are connected in parallel between the output terminals of the full-wave rectifier circuit, and the full-wave rectifier circuit is connected to the AC power supply. , A LC resonance circuit is connected to the input side or output side of the full-wave rectifier circuit, and switching means is connected between the input terminal of the full-wave rectifier circuit and a connection point between the voltage doubler capacitors, A control unit that outputs a control signal for operating the switching unit when the load is equal to or more than a predetermined load.

According to a second aspect of the present invention, in the power supply apparatus, the switching means is connected between an input terminal of the full-wave rectifier circuit connected to a terminal to which neither the reactor of the AC power supply nor the LC resonance circuit is connected and the capacitor for voltage doubler. It is connected between points. The power supply device according to claim 3, wherein the control means determines whether the load is equal to or more than a predetermined load by using a DC output voltage as an input, and outputs a control signal for operating the switching means when the load is equal to or more than the predetermined load. The output is adopted.

According to a fourth aspect of the present invention, as the control means, the DC output voltage and the DC output current are input to determine whether or not the load is equal to or greater than a predetermined load. One that outputs a control signal for operating the means is employed. 6. The power supply device according to claim 5, wherein the control means determines whether a load is equal to or more than a predetermined load by using an input voltage and an input current as inputs, and operates the switching means when the load is equal to or more than the predetermined load. The one that outputs a signal is adopted.

[0012]

According to the power supply device of the present invention, a full-wave rectifier circuit is connected between both terminals of the AC power supply, and a smoothing capacitor and a voltage doubler capacitor are connected in parallel between the output terminals of the full-wave rectifier circuit. Connect the reactor between the full-wave rectifier circuit and the AC power supply, connect the LC resonance circuit to the input or output side of the full-wave rectifier circuit, and connect the input terminal of the full-wave rectifier circuit and the capacitor for voltage doubler. The switching means is connected between the connection points and the control means for outputting a control signal for operating the switching means when the load is equal to or more than a predetermined load. It is possible to achieve the reduction of the harmonic current. DC output voltage as compared with the case where the flow operation can be increased.

According to the power supply device of the present invention, the switching means is connected between the input terminal of the full-wave rectifier circuit connected to the terminal of the reactor to which neither the reactor of the AC power supply nor the LC resonance circuit is connected, and the capacitor for voltage doubler. Therefore, the same operation as the first aspect can be achieved. The power supply device according to claim 3, wherein the control means determines whether the load is equal to or more than a predetermined load by using a DC output voltage as input, and controls the switching means to operate when the load is equal to or more than the predetermined load. Since a device that outputs a signal is employed, the same operation as the first aspect can be achieved.

According to the power supply device of the present invention, the control means determines whether or not the load is equal to or more than a predetermined load by using the DC output voltage and the DC output current as inputs. A device for outputting a control signal for operating the switching means is adopted in claim 1.
The same operation as described above can be achieved. In the power supply device according to claim 5, as the control means, it is determined whether or not the load is equal to or more than a predetermined load by using the input voltage and the input current as inputs, and the switching means is operated when the load is equal to or more than the predetermined load. Since the output of the control signal to be performed is adopted, the same operation as the first aspect can be achieved.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a power supply apparatus according to an embodiment of the present invention. FIG. 5 is an electric circuit diagram showing one embodiment of the power supply device of the present invention.
In the power supply device of this embodiment, a full-wave rectifier circuit 2 is connected between both terminals of an AC power supply 1, and has a capacitance equal to a smoothing capacitor C2 between output terminals of the full-wave rectifier circuit 2. And the voltage doubler capacitors C11 and C12 connected in series with each other are connected in parallel to each other, and the reactor 3, the reactor 4a, and the capacitor 4b are connected between one terminal of the AC power supply 1 and the full-wave rectifier circuit 2. An LC resonance circuit 4 connected in series is connected in parallel with each other, and between an input terminal of the full-wave rectification circuit 2 connected to the other terminal of the AC power supply 1 and a connection point between the voltage-doubling capacitors C11 and C12. And a control circuit 5 for controlling the operation of the relay contact MR.

The control circuit 5 receives a DC output voltage and outputs a control signal for instructing to turn on the relay contact MR on condition that the DC output voltage falls below a predetermined voltage set in advance. It is. When the power supply device of this embodiment is employed, when the DC output voltage is equal to or higher than a predetermined voltage set in advance, the load is light, so the relay contact MR is off, and “ As shown by the solid line in the “relay: off” region, a full-wave rectification operation can be performed to supply a DC output voltage to the load.

When the DC output voltage is lower than a predetermined voltage set in advance, the load is heavy, so the relay contact MR is turned on based on a control signal from the control circuit 5, and the relay contact MR in FIG. As shown by the solid line in the area of “relay: on”, a sufficiently large DC output voltage can be supplied to the load by performing the voltage doubler rectification operation. Therefore, it is possible to compensate for a voltage drop due to the reactor due to an increase in current under heavy load.

The resonance circuit of the power supply device during the period in which the voltage doubler rectification operation is performed is shown in FIG.
This is a circuit obtained by combining the resonance circuits shown in the middle (B). By combining the resonance currents i1 and i2 flowing through the two resonance circuits, the conduction angle is advanced and delayed as shown by the solid line in FIG. Therefore, improvement of the power factor and reduction of harmonics can be achieved.

Furthermore, in the power supply device of this embodiment, the DC output is reduced by making the capacitance of the voltage doubler capacitors C11 and C12 smaller than the capacitance of a capacitor used in a general voltage doubler rectifier circuit. The voltage can be set to any voltage that does not cause overvoltage. FIG. 9 is an electric circuit diagram showing another embodiment of the power supply device of the present invention.

This power supply device is different from the power supply device of FIG. 5 in that the reactor 3, the reactor 4a, and the capacitor 4b
Are replaced by a parallel connection circuit with the LC resonance circuit 4 which is connected in series with each other. Of the reactors required for the resonance currents i1 and i2 of the resonance circuits shown in FIGS. 7A and 7B, The only point is that the common portion 3 'is put together on one current path where the resonance currents i1 and i2 join.

Therefore, when this embodiment is adopted, the same operation as that of the power supply device of FIG. 5 can be achieved.
The size of the entire reactor can be reduced as compared with the power supply device of FIG. FIG. 10 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention. This power supply device differs from the power supply devices of FIGS. 5 and 9 only in that two reactors are formed by one core and not only self-inductance but also mutual inductance is used.

Therefore, when this embodiment is adopted, the same operation as that of the power supply device shown in FIGS. 5 and 9 can be achieved, and the size of the whole reactor can be reduced compared to the power supply device shown in FIGS. Cost reduction can be achieved. FIG.
FIG. 7 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention. This power supply device is different from the power supply devices in FIGS. 5 and 9 in that the smoothing capacitor C2 and the voltage-doubling capacitors C11 and C12 connected in series with each other so as to configure the LC resonance circuit on the DC side. The reactor 4a is connected to the reactor 4a and the voltage doubler capacitor C11.
And that only the LC resonance circuit is constituted.

Therefore, when this embodiment is adopted, the same operation as that of the power supply device shown in FIGS. 5 and 9 can be achieved, and it is not necessary to provide a special capacitor for constituting the LC resonance circuit. The cost can be reduced by reducing the number of points. In addition, FIG. 5, FIG. 9, FIG.
0, in the embodiment of FIG. 11, a relay contact MR can be connected between the other input terminal of the full-wave rectifier circuit 2 and a connection point of the voltage-doubling capacitors C11 and C12. Can be achieved. FIG. 12 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention. This power supply device is for eliminating the case where the resonance current continues to flow even during the period when the input current is zero in the power supply device of FIG.

In this power supply device, a three-phase full-wave rectifier circuit 6 in which three pairs of diode series-connected circuits are connected in parallel with each other instead of the full-wave rectifier circuit 2 is employed. Are connected to the first and second input terminals of the three-phase full-wave rectifier circuit 6, respectively, and the other terminal of the AC power supply 1 is connected to the three-phase full-wave rectifier circuit 6. It is connected to the third input terminal of the wave rectifier circuit 6. The configuration of the other parts is the same as that of the embodiment shown in FIG. 5, and a detailed description thereof will be omitted.

When this embodiment is adopted, FIG.
As shown in (3), the resonance current during the period when the input current is zero can be suppressed by the three-phase full-wave rectifier circuit 6, and the loss can be reduced. 14 and 15 are electric circuit diagrams showing still another embodiment of the power supply device of the present invention.

These power supplies are intended to eliminate the occurrence of extra loss due to the continuous flow of the resonance current even during the period when the input current is zero in the power supplies of FIGS. 9 and 10. Specifically, similarly to the power supply device of FIG. 12, a three-phase full-wave rectifier circuit 6 in which three pairs of diode series-connected circuits are connected in parallel to each other instead of the full-wave rectifier circuit 2 is employed. The configuration of the other parts is the same as that of the embodiment shown in FIGS. 9 and 10 and the embodiment shown in FIG.

Therefore, even when these embodiments are adopted, the resonance current during the period when the input current is zero can be suppressed by the three-phase full-wave rectifier circuit 6, and the loss can be reduced. FIG. 16 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention. This power supply device is for eliminating the case where the resonance current continues to flow even during the period in which the input current is zero in the power supply device of FIG.

In this power supply device, the smoothing capacitor C2
And a capacitor C1 for voltage doubler connected in series with each other.
1 and C12, a series connection circuit of the reactor 4a and the diode 7 is connected. The configuration of the other parts is the same as that of the embodiment shown in FIG. 11, and a detailed description thereof will be omitted. Therefore, even when these embodiments are adopted, the resonance current during the period when the input current is zero can be suppressed by the diode 7, and the loss can be reduced.

FIG. 17 is a block diagram showing another configuration example of the control circuit. The control circuit 15 receives the DC output voltage and the DC output current as input, calculates the DC output power, compares the DC output power with a predetermined power set in advance, and calculates the calculated DC output power in advance. It outputs a control signal instructing to turn on the relay contact MR on condition that the power exceeds a certain predetermined power.

Therefore, the voltage doubler rectification operation can be performed only when the calculated DC output power exceeds a predetermined power (when the load is heavy). FIG. 18 is a block diagram showing still another configuration example of the control circuit. The control circuit 25 receives a DC input voltage and a DC input current as input, calculates DC input power, compares the DC input power with a predetermined power, and calculates the calculated DC input power. It outputs a control signal instructing to turn on the relay contact MR on condition that the power exceeds a certain predetermined power.

Therefore, the voltage doubler rectification operation can be performed only when the calculated DC input power exceeds a predetermined power set in advance (when the load is heavy). 17 and FIG. 18 are shown as harmonic reduction circuits in FIG. 5 and FIG. 9 to FIG.
16 includes a reactor, a resonance circuit, a full-wave rectifier circuit, a smoothing capacitor, a doubler capacitor, and a relay contact in any one of the power supply devices shown in FIGS.

[0032]

According to the first aspect of the present invention, the power factor can be improved by the LC resonance circuit, the harmonic current can be reduced, and the switching means is controlled by the control means when the load is equal to or more than a predetermined load. Is operated to perform the voltage doubler rectification operation, which has a specific effect that the DC output voltage can be increased as compared with the case where the full-wave rectification operation is performed.

The second aspect of the invention has the same effect as the first aspect. The third aspect of the invention has the same effect as the first aspect. The invention of claim 4 has the same effect as that of claim 1. The invention of claim 5 has the same effect as that of claim 1.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing an example of a conventional power supply device.

FIG. 2 is a diagram showing an input voltage waveform and an input current waveform of the power supply device of FIG.

FIG. 3 is an electric circuit diagram showing another example of a conventional power supply device.

4 is a diagram showing an input voltage waveform and an input current waveform of the power supply device of FIG.

FIG. 5 is an electric circuit diagram showing one embodiment of the power supply device of the present invention.

FIG. 6 is a diagram showing a change in DC output voltage with respect to input power.

7 is an electric circuit diagram showing a resonance circuit of the power supply device of FIG.

8 is a diagram illustrating an input voltage waveform, an input current waveform, and a resonance current waveform of the power supply device of FIG. 5;

FIG. 9 is an electric circuit diagram showing another embodiment of the power supply device of the present invention.

FIG. 10 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

FIG. 11 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

FIG. 12 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

13 is a diagram showing an input voltage waveform, an input current waveform, and a resonance current waveform of the power supply device of FIG.

FIG. 14 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

FIG. 15 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

FIG. 16 is an electric circuit diagram showing still another embodiment of the power supply device of the present invention.

FIG. 17 is a block diagram illustrating another configuration example of the control circuit.

FIG. 18 is a block diagram showing yet another configuration example of the control circuit.

[Explanation of symbols]

Reference Signs List 1 AC power supply 2 Full-wave rectifier circuit 3 Reactor 4 LC resonance circuit 5, 15, 25 Control circuit 6 3-phase full-wave rectifier circuit C11, C12 Doubler capacitor C2 Smoothing capacitor MR relay contact

Claims (5)

[Claims] 1. A full-wave rectifier circuit (2) (6) is connected between both terminals of an AC power supply (1), and a smoothing capacitor (C2) is connected between output terminals of the full-wave rectifier circuits (2) and (6). And the voltage doubler capacitors (C11) and (C12) are connected in parallel with each other,
A reactor (3) is connected between the full-wave rectifier circuits (2) and (6) and the AC power supply (1), and an LC resonance circuit (4) is connected to the input side or the output side of the full-wave rectifier circuits (2) and (6). ) And connect
Switching means (MR) is connected between the input terminals of the full-wave rectifier circuits (2) and (6) and the connection point between the voltage doubler capacitors (C11) and (C12), and when the load is equal to or more than a predetermined load. A power supply device comprising control means (5), (15), and (25) for outputting a control signal for operating a switching means (MR). The switching means (MR) includes a full-wave rectifier circuit (2) (6) connected to a terminal of the AC power supply (1) to which neither the reactor (3) nor the LC resonance circuit (4) is connected. ) Input terminal and a capacitor for voltage doubler (C1
The power supply device according to claim 1, wherein the power supply device is connected between (1) (C12) and another connection point. 3. The control means (5) determines whether a load is equal to or more than a predetermined load by using a DC output voltage as an input, and
When the load is equal to or more than a predetermined load, the switching means (M
3. The power supply device according to claim 1, wherein the power supply device outputs a control signal for operating R). 4. The control means (15) receives a DC output voltage and a DC output current as inputs and determines whether a load is equal to or more than a predetermined load, and when the load is equal to or more than a predetermined load, switches (MR). 3. The power supply device according to claim 1, wherein the power supply device outputs a control signal for operating the power supply. 5. The control means (25) determines whether a load is equal to or more than a predetermined load by using an input voltage and an input current as inputs, and switches the switching means (MR) when the load is equal to or more than the predetermined load. 3. The power supply device according to claim 1, wherein the power supply device outputs a control signal for operating the power supply.