JP2003009535A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply which can smoothly adjust the output voltage over a wider range of a voltage through full-wave rectifier and a voltage obtained through voltage-doubler rectifier, while power factor is improved with a simplified structure and restriction for harmonics is cleared. SOLUTION: This power supply is provided with a switch SW1 which is connected between an input terminal of a rectifier circuit 2 and a connecting point of capacitors 4, 5 for voltage-doubler rectifier, and a switch SW2 connected between the other input terminal of the rectifier circuit 2 and a connecting point of capacitors 4, 5. In the operation mode 1, the switch SW1 is continuously controlled to ON state only during the period up to the ON period which changes depending on an output voltage from the zero-crossing point of the power supply voltage, and the switch SW2 is always controlled to the OFF stage. In the operation mode 2, the switch SW1 is continuously controlled to the ON state only during the period up to the ON period from the zero-crossing point of the power source voltage, while the switch SW2 is always controlled to the ON state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device,
The present invention relates to a power supply device that converts a constant AC power supply into a direct current having a desired voltage.

[0002]

2. Description of the Related Art In a power supply device used for electric equipment such as an air conditioner, it is necessary to clear the harmonic regulation.
There is a method of improving the power factor by using the active filter disclosed in Japanese Patent Application Laid-Open No. -11128. According to the active filter, the effect that the power factor is improved and the power supply voltage boosting function can be realized secondarily is obtained. On the other hand, there is a problem that the circuit scale increases and the manufacturing cost increases.

To achieve the same effect as an active filter with a simple structure, Japanese Patent Laid-Open No. 2000-1 has been proposed.
The technique disclosed in Japanese Patent No. 888867 has been devised.
FIG. 14 shows the configuration. As shown in FIG. 14, the power supply device includes a switch SW11 that is connected between the input ends of the rectifier circuit 2 and short-circuits / interrupts the input ends, a midpoint of a diode bridge that constitutes the rectifier circuit 2, and a voltage doubler rectifier. And a switch SW12 which is connected to the connection point between the condensers 4 and 5 and short-circuits / interrupts the connection.

In this power supply device, the power factor is improved and the boosting function is realized by controlling the ON / OFF of the switch SW11 by a pulse width (PWM) control as in the case of using the active filter. Further, the variable range of the output voltage is expanded by switching between full-wave rectification and voltage doubler rectification by turning on / off the switch SW12. That is, when the load is small, the switch SW12 is turned off to operate in the full-wave rectification mode, and when the load is large, the switch SW12 is turned on to operate in the voltage doubler rectification mode, thereby expanding the variable range of the output voltage. ing.

[0005]

However, as shown in FIG.
The power supply device shown in 1 has the following problems. Switch S
The pulse width of W1 is controlled. At this time, since the carrier frequency of the pulse width control is a frequency extremely higher than the power supply frequency, the generation of high frequency noise becomes a problem. Therefore, a separate filter circuit is required as a measure against noise,
This leads to an increase in manufacturing cost. Further, when the switch SW12 switches between full-wave rectification and voltage doubler rectification, the output voltage fluctuates greatly. That is, there is a problem that the voltage difference between the output voltage immediately before the switching of the operation mode and the output voltage immediately after the switching is large.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the power factor with a simple structure, clear the harmonic regulation, and output voltage when switching the operation mode. An object of the present invention is to provide a power supply device that suppresses sudden changes in the power supply.

[0007]

A power supply device according to the present invention has two input terminals and two output terminals and is connected to an AC power supply via a reactor to convert an AC power supply voltage into a DC voltage. A rectifier circuit and a plurality of capacitors connected in series, a capacitor circuit connected between two output terminals of the rectifier circuit, one input terminal of the rectifier circuit, and one capacitor between the capacitors in the capacitor circuit. A first switch means connected to the connection point, a second input means of the rectifier circuit, and a second switch means connected to the same connection point between the capacitors in the capacitor circuit. Become.

The power supply device may include control means for controlling the first and second switch means in one of the first and second operation modes. At this time, in the first operation mode, the first switch means is continuously turned on only during a first on period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage,
The second switch means is controlled to be always off. In the second operation mode, the first switch means is controlled to be continuously turned on only during a first ON period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage, and the second switch is operated. Control the means always on.

The control means changes the operation mode used for controlling the first and second switch means from the first operation mode to the second operation mode when the first ON period becomes larger than a predetermined value. You may make it switch to.

Further, the control means sets the operation mode used for controlling the first and second switch means from the second operation mode to the first operation mode when the first ON period becomes zero.
The operation mode may be switched to.

Further, the control means sets the operation mode used for controlling the first and second switch means to the second operation mode after the first ON period becomes zero and a predetermined time elapses in that state. May be switched to the first operation mode.

Further, the control means controls the second operation mode from the first operation mode when the control in the second operation mode continues for a predetermined time or more and the first ON period becomes zero. You may make it switch to an operation mode.

Further, the control means may further provide a second ON period for turning on the first switch means in the half cycle of the power supply, in addition to the first ON period.

The control means turns on / off the second switch means.
The OFF switching may be performed at the time of zero crossing of the power supply voltage.

The control means may start the first ON period at the zero cross point of the power supply voltage.

The control means may start the first ON period after a predetermined time has elapsed from the zero cross point of the power supply voltage.

The second switch means may be composed of a relay.

The operation mode may be set in the power supply device as follows. That is, in the first operation mode, the first switch means is continuously turned on only during a first on period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage. The second switch means is controlled to be always off. In the second operation mode, the first switch means is always turned on, and the second switch means is continuously turned on only during a second on period during which a half cycle of the power supply voltage changes according to the output voltage of the power supply device. Control on.

Further, the operation mode may be set as follows. That is, in the first operation mode, pulse width control is performed on the first switch means with a cycle shorter than a half cycle of the power supply voltage as a carrier cycle, and the second switch means is constantly turned off. In the second mode of operation,
The pulse width control is performed on the first switch means in the carrier period, and the second switch means is constantly turned on.

Further, the control means may control the increase / decrease amount of the first ON period per half cycle of the power supply voltage to be larger in the first operation mode than in the second operation mode. .

Further, the control means switches the first and second switch means for a half cycle or more of the power supply voltage when switching from one mode of the first or second operation mode to the other mode. Both may be turned off once and then the operation mode may be switched.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a power supply device according to the present invention will be described in detail below with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a diagram schematically showing a circuit configuration of a power supply device according to the present invention. As shown in the figure, the power supply device supplies the voltage from the AC power supply 1 to the reactor 3
A rectifier circuit 2 for rectifying by inputting via a capacitor, a capacitor for double voltage rectification 4, 5 and a connection point between the midpoint of each half bridge of the rectifier circuit 2 and capacitors for double voltage rectification 4, 5. And switches SW1 and SW2 for switching. The power supply device rectifies the voltage from the AC power supply 1 and outputs a DC voltage of a desired magnitude to the load 8. The load 8 is a DC used in a compressor such as an air conditioner or a refrigerator, or a washing machine.
An inverter and the like for driving the motor are included.

The rectifier circuit 2 comprises a half bridge of two diodes. The capacitors 4 and 5 are connected in series and connected to the output terminal of the rectifier circuit 2. The switches SW1 and SW2 are connected between the respective input ends of the rectifier circuit 2 (the midpoints of the respective half bridges of the rectifier circuit 2) and the connection points between the capacitors 4 and 5.
The number of capacitors for double voltage rectification is not limited to two, and an even number can be provided.

The power supply device configured as described above operates in two operation modes (mode 1 and mode 2) according to the on / off states of the switches SW1 and SW2. (A)
Mode 1: The switch SW1 is pulse-width controlled while the switch SW2 is always off. In mode 1, an output voltage in the range of approximately √2 to 2√2 times the power supply voltage can be obtained. (B) Mode 2: Switch SW2 is always on or in a state where pulse width is controlled, and switch SW2
1 is pulse width controlled. Since the circuit configuration is based on the voltage doubler rectifier circuit in mode 2, it is possible to obtain an output voltage that is 2√2 times or more the power supply voltage.

The pulse width control of the switches SW1 and SW2 is performed by controlling the pulse width of the control pulse output to them. Here, only one control pulse is output for each half cycle of the power supply voltage. Hereinafter, such switching control using only one pulse output every half cycle is referred to as "one-pulse control". This one-pulse control is equivalent to the control when the carrier cycle in the pulse width control is set to the half cycle of the power supply voltage.

In the 1-pulse control, 10 times twice the power supply frequency is used.
It is based on a low speed switching operation such as 0 Hz or 120 Hz. Therefore, unlike the active filter system, there is no high-speed switching operation of several tens of kHz, and the generated noise is small. Therefore, there is an advantage that a circuit for noise suppression can be simplified, which is advantageous in terms of space and cost.

Further, in the present invention, the switch SW2 is controlled to be either constant ON or constant OFF regardless of the operation mode of mode 1 or mode 2, and basically except when the mode is switched. No switching operation is required. Therefore, a relatively slow switching element such as a relay can be used as the switch SW2.

FIG. 2 is a diagram showing a more specific structure of the power supply device of the present invention. In FIG. 2, the switch SW1
Is a bidirectional semiconductor switch, and the switch SW
2 is composed of a relay. By using a relay for the switch SW2, it is possible to reduce loss when the switch is turned on, as compared with the case where a semiconductor switch such as an IGBT is used. In addition to the configuration shown in FIG. 1, the power supply device shown in FIG. 2 further includes a smoothing capacitor 11, a power supply phase detection unit 12 that detects the phase of the power supply voltage, and a pulse width control that controls the pulse width of the switch SW1. Section 13 and switch SW
Relay ON / OFF control unit 1 for controlling ON / OFF of 2
4 and an output voltage detector 15 that detects the output voltage. By inserting the smoothing capacitor 11, it is possible to suppress the capacitance variation due to the switching of the operation mode, and it is possible to supply a more stable voltage.

In the power supply device configured as described above, the pulse width control unit 13 switches based on the detection result of the output voltage from the output voltage detection unit 15 and the detection result of the power supply phase from the power supply phase detection unit 12. A control pulse is output so as to control the on / off timing of SW1. The pulse width control unit 13 outputs a control pulse at the timing when the power supply phase becomes zero cross. In addition, relay ON / OF
The F control unit 14 outputs a control pulse to control the on / off timing of the switch SW2.

The operation of the power supply device in each operation mode will be described with reference to FIG. 3 (b) shows how the duty ratio of the switch SW1 changes, and FIG. 3 (c) shows the switch S1.
The on / off state of W2 is shown. FIG. 3A shows a change in the output voltage corresponding to the state of each switch when a constant load is output (about 400 W).

The horizontal axis in the figure represents possible control states, but when explaining the case where the state transitions in accordance with the target output voltage, the horizontal axis is regarded as the time axis, and from left to right, or It may be seen that the control state changes from right to left.

As shown in FIG. 3, in the mode 1,
With the switch SW2 always off, the pulse width of the switch SW1 is controlled according to the required output voltage (see the figure).
Point P). That is, in mode 1, when it is desired to obtain a higher output voltage, the pulse width of the control pulse of the switch SW1 is increased. At that time, the duty ratio with respect to the switch SW1 reaches 100% (at this time, the switch SW1 is controlled to be turned on during a half cycle of the power supply frequency),
Further, when a higher output voltage is required, the pulse width of the switch SW1 cannot be controlled further, so that the operation mode is switched from the mode 1 to the mode 2.

Before and after switching from mode 1 to mode 2, the duty ratio of the switch SW1 is 100% to 0%.
The switch SW2 is switched from off to on (point Q in the figure). At this time, since the circuits before and after the switching are the double voltage rectification circuits themselves, the output voltage does not fluctuate before and after the switching. In addition, mode 2
Then, the switch SW2 is controlled to be always on, and the switch SW1 is pulse width controlled according to the output voltage (R in the figure).
point). In the mode 2, since the circuit configuration is based on the voltage doubler rectifier circuit, an output voltage about twice as high as that in the mode 1 can be obtained.

When the output voltage is lowered in the mode 2, when the duty ratio of the switch SW1 reaches 0%, the switch SW2 is switched from on to off and the duty ratio of the switch SW1 is changed from 0% to 100%. By this, the mode 2 is switched to the mode 1.

In FIG. 3, in Mode 1, the output voltage does not rise until the control pulse becomes large to some extent, but this is because the power supply voltage is small and the input current does not flow in the section where the control pulse is small. The output voltage does not rise even when the control pulse approaches 100%, but this is also the same.

In mode 1, the switch SW1
The increase of the output voltage with respect to the increase of the duty ratio of the
It is lower than that of mode 2 which forms the short loop of. Therefore, as shown in FIG. 3, the increase / decrease amount of the duty ratio of the switch SW1 in mode 1 is set larger than the increase / decrease amount in mode 2 (inclination is set to be large in the figure).
By doing so, the follow-up speed of the output voltage in the feedback operation is controlled to be substantially the same between both operation modes. This makes it possible to keep the output voltage following speed substantially constant in the entire output voltage range.

Further, in the above example, the switch SW2 is
Although the mode 2 is immediately switched to the mode 1 when the duty ratio becomes 0%, the mode may be switched when a certain time (for example, 1 hour or more) has elapsed while the duty ratio becomes 0%. . By performing this control, the state in which the output voltage is higher than the target output voltage is temporarily maintained, but the switch SW2 is switched when a load that frequently travels between the mode 1 and the mode 2 is assumed. The frequency can be greatly reduced.

Further, the duration of the control in the mode 2 is measured, and the duration is a predetermined time or more, and
The mode 2 may be switched to the mode 1 when the duty ratio of the switch SW1 becomes 0%. In this case, even if the duty ratio of the switch SW1 becomes 0%, if the duration of the control in the mode 2 is not longer than the predetermined time, the mode is not switched, and then the duration of the control in the mode 2 is continued. When is over a predetermined time, the mode 2 is switched to the mode 1.

Generally, in the case of a DC motor load, the motor can be rotated by PWM control even if the output voltage is high, and even if the output voltage temporarily becomes higher than the target value by this control, the desired rotation speed Since the motor can be rotated by, the effect is small. On the contrary, when the DC motor is operated at a high rotation speed, it is necessary to increase the output voltage according to the induced voltage of the DC motor that is the load.

In the above control, no time limitation is applied when switching from mode 1 to mode 2, so that the output voltage can be quickly raised even when the motor load suddenly increases. On the other hand, when the switch SW2 is configured by a relay, the switching frequency of the switch SW2 is reduced by performing the above control, and it becomes possible to secure the contact life required for guaranteeing the product life.

FIG. 4 shows a mode 1 of the power supply device of this embodiment.
, The control pulse for the switches SW1 and SW2, the power supply voltage, the input current, the output voltage (smoothing capacitor 1
2 is a diagram showing respective waveforms of the voltage at the connection point of capacitors 4 and 5). As shown in the figure, the control pulse of the switch SW1 is output at the zero-cross position of the power supply voltage, and only one is output for each half cycle of the power supply voltage. As shown in the figure, this control pulse causes the input current to start flowing when the power supply voltage becomes equal to or higher than the midpoint voltage of the capacitors 4 and 5. That is, the input current can be made to conduct extra during the period A, and the current conduction period can be extended in this way, so that the power factor can be improved. Further, since the waveform of the input current can be made close to the waveform of the power supply voltage, the high frequency regulation can be cleared.

At the time of mode switching, it is preferable that the switch SW2 is switched on / off at the zero-cross position of the power supply voltage. Further, in the example shown in FIG. 4, the control pulse for the switch SW1 is output at the zero-cross position of the power supply voltage, but it may be output with a delay of a predetermined time from the zero-cross timing of the power supply voltage.

FIG. 5 shows a mode 2 of the power supply device of this embodiment.
6 is a diagram showing waveforms of control pulses, power supply voltage, and input current for switches SW1 and SW2 in FIG. In the figure, the control pulse of the switch SW1 is output after being delayed by a predetermined delay time Td from the zero cross position of the power supply voltage. The delay time Td must be set to a value that can clear the harmonic regulation. The delay time Td is
It is easier to clear the harmonic regulation by setting a larger value as the load output becomes smaller, but it is not always necessary. Therefore, the delay time Td may be set to 0 (that is, the switch SW1).
The control pulse may be output at the zero-cross timing. ). In mode 1, even if the control pulse is turned on, the input power does not begin to flow until the power supply voltage becomes equal to or higher than the midpoint voltage of the capacitors 4 and 5, whereas in mode 2, the control pulse of the switch SW1. The input current begins to flow at the same time that the switch turns on. As described above, by turning on the switch SW1, it becomes possible to conduct an extra input current during the pulse width period Tw, so that the current conduction period can be extended as in the case of mode 1, and the power factor can be increased. Can be improved. Furthermore, the waveform of the input current can be made closer to the waveform of the power supply voltage, and the high frequency regulation can be cleared.

FIG. 6 is a diagram for explaining changes in the power supply voltage and the input current at the time of mode switching. As shown in the figure, the output voltage hardly changes immediately before and after the mode switching. The input current in the power supply half cycle X immediately after the mode switching has a slightly small peak value and a little larger in the next half cycle Y, but its fluctuation degree is sufficiently small. The reason why the input current has such a waveform is that the double voltage capacitors 4 and 5 charged with respect to the phase of the input power supply voltage are exchanged before and after the mode switching, and in the period X, during the immediately preceding half cycle. This is because the capacitor 5 has already been charged therein, so that the charging current to the capacitor 5 does not flow so much and the voltage of the capacitor 4 decreases during the next half period Y, so that the charging current increases.

As a result, there is no change in the current waveform during mode switching, and the output voltage can be changed smoothly within the output voltage range. That is, it is possible to suppress a sudden change in the output voltage even when the target output voltage is changed over between the two operation modes.

In the above example, as shown in FIGS.
The switching from the mode 1 to the mode 2 was performed when the duty ratio of the switch SW1 in the mode 1 reached 100%. However, even before the duty ratio of the switch SW1 reaches 100%, the mode may be switched when the predetermined duty ratio close to 100% (for example, about 80%) is reached. FIG. 7 shows changes in the duty ratios of the switches SW1 and SW2 when mode switching is performed when the duty ratio of the switch SW1 reaches 80%, and changes in the output voltage corresponding to each switch state. FIG. 8 is a diagram illustrating control pulses and changes in the power supply voltage and the input current when the mode is switched at a duty ratio of 80%. In this case as well, similar to the case of mode switching at a duty ratio of 100%, almost the same current waveform is obtained immediately before and after mode switching, and the output voltage is smoothly changed within the output voltage range during mode switching. it can.

In FIG. 7, although an output voltage difference of about 10 V is generated before and after the mode switching, the reactor 3 is set to about 4 to 6 mH, and the capacitors 4 and 5 are set to 100.
When the duty ratio at the time of switching is set to about 0 μF and the duty ratio at the time of switching is set to about 90%, the output voltage difference at the time of mode switching can be made substantially zero. This is because, as described with reference to FIG. 3, if the duty ratio is about 90%, the input current is zero in the remaining section corresponding to 10%, and the circuit is equivalent to the voltage doubler rectification. . In this case, the section where the output voltage does not increase even if the duty ratio of the switch SW1 is increased, which occurs near the duty ratio of 100%, is reduced as compared with the case where the control for switching at the duty ratio of 100% is performed. Therefore, when the mode 1 is switched to the mode 2, the output voltage can be made to follow the target output voltage faster.

(Second Embodiment) Another example of the control method of the switches SW1 and SW2 in the operation mode of the power supply device will be described with reference to FIG.

FIG. 9 shows the switches SW1 and S of the present embodiment.
It is a figure explaining control of W2. As shown in FIG. 9, the control of the mode 1 of the present embodiment is the same as that of the case of the first embodiment shown in FIG. However, in the control of mode 2,
In the first embodiment, the switch SW2 is constantly turned on and the switch SW1 is controlled in pulse width, whereas in the present embodiment, the switch SW1 is always turned on (that is, the duty ratio is set to 100%), and the semiconductor The pulse width of the bidirectional switch SW2 including a switch is controlled according to the output voltage.

Even when the switches SW1 and SW2 are controlled as described above, the input current waveform can be smoothly connected before and after the mode switching, and the output voltage fluctuations at the time of mode switching, as in the case of the first embodiment. Can be suppressed. Since the above control is performed, it is difficult to use a relay for the switch SW2, but there is an advantage that it is easy to switch the switch SW2 accurately at the zero cross position of the power supply voltage.

In the case of switching the mode as described above, the mode may be switched when the duty ratio of the switch SW1 reaches a predetermined duty ratio near 100%. That is, as shown in FIG.
The switching from the mode to the mode 2 may be performed when the duty ratio of the switch SW1 reaches 90%. At this time, regarding the switch SW1, even after switching to the mode 2,
The pulse width is controlled until the duty ratio reaches 100%.

Even with the above control, similar effects can be obtained before and after the mode switching, as in the case described above.

In the first and second embodiments, the "one-pulse control" in which only one control pulse is applied in a half cycle of the power supply voltage has been described, but the carrier frequency is set to the power supply frequency for the switch SW1. Then, the frequency may be set to a very high frequency (that is, a carrier cycle that is very short compared to the half cycle of the power supply voltage) and pulse width control may be performed at the carrier frequency.

(Third Embodiment) In the first embodiment, as shown in FIG. 4, "one-pulse control" in which only one control pulse is applied to the switch SW1 in a half cycle of the power supply voltage.
Was being done. On the other hand, in the present embodiment, FIG.
As shown in FIG. 5, control for applying two control pulses to the switch SW1 in a half cycle of the power supply voltage (hereinafter referred to as “two-pulse control”) is performed. At this time, the pulse in the first half is applied when the zero cross of the power supply voltage occurs, and the pulse in the latter half is applied near the time when the input current becomes zero in the one-pulse control. The second half pulse has a smaller pulse width than the first half pulse. By thus performing the 2-pulse control, it becomes possible to conduct the input current not only in the period A but also in the period B, so that the power factor can be further improved and the power supply efficiency can be improved.

(Fourth Embodiment) In the first embodiment, when shifting from one operation mode to the other operation mode, the switches SW1 and SW2 are controlled to be switched within a half cycle of the same power supply voltage. It was On the other hand, in the present embodiment, as shown in FIGS. 12 and 13, at the time of switching between the two operation modes, first, the switches SW1 and SW2 are both turned off for a half cycle of the power supply voltage, and then the operation mode is changed. Switch. In addition, the switches SW1, S
The period in which both W2 are turned off (hereinafter referred to as "dead time") may be longer than the half cycle of the power supply voltage.

FIG. 12 is a diagram for explaining changes in the power supply voltage, the input current and the output voltage when the mode 1 is switched to the mode 2. As shown in the figure, almost the same current waveform as in the case of the first embodiment is obtained before and after the mode switching except that the input current is zero during the power supply half cycle immediately before the mode switching. Also, switches SW1 and S
During the period (dead time) in which both W2 are turned off, the output voltage drops by about 20 to 30 V in peak value, but the ripple voltage in the steady state is also about the same, so the output voltage does not fluctuate significantly. Absent. Therefore, also in this control, the output voltage can be smoothly changed when the mode is switched. That is, it is possible to suppress a sudden change in the voltage when the target output voltage is changed.

FIG. 13 shows waveforms at the time of switching from mode 2 to mode 1. As in the case of FIG. 12, the switch SW1,
Although the output voltage temporarily drops during the period (dead time) in which both SW2 are turned off, the peak value is 20
It is about 30 V, and the fluctuation of the output voltage is suppressed.

When the switch SW2 is a relay, the relay is turned on in consideration of the operating time of the switch SW2.
The ON / OFF control unit 14 outputs an ON or OFF control signal at a time point before the zero cross of the power supply voltage for which the mode is to be switched.
Even when the OFF operation of W2 is delayed by about 10 ms from the TYP value, the switches SW1 and SW2 are never turned on because the dead time is provided. Therefore, even when there is a large variation in the operating time of the switch SW2, by performing this control, it is possible to reliably avoid an increase in the output voltage caused by the boosting action due to the formation of the short loop of the AC power supply 1.

[0060]

According to the present invention, first and second switch means are provided between the connection point between a plurality of capacitors connected in series on the output side and each input terminal of the rectifier circuit. In the above configuration, by switching the ON / OFF combination of each switch means, it is possible to configure a power supply circuit having a boosting action, which is based on the full-wave rectifier circuit and the voltage doubler circuit. As a result, while improving the power factor and clearing the harmonic regulation, a wide range (120 to 2
It is possible to configure a power supply device having an output voltage range of about 90V.

According to the invention of claim 2, the operation mode is switched by turning on or off the second switch means, and the first switch means is changed in half cycle of the power supply according to the output voltage. By controlling to continuously turn on only during the ON period, the harmonic regulation can be cleared and a desired output voltage can be obtained by simple control. Further, since the operation is performed by the low frequency switching, the generated switching noise can be suppressed to be relatively small.

According to the invention of claim 3, the first
When the ON period in the operation mode becomes larger than the predetermined value, the first switch means is turned off, and the second switch means is turned on to shift to the second operation mode. It is possible to suppress the fluctuation of the output voltage that sometimes occurs.

According to the invention of claim 4, the second aspect is provided.
When the ON period in the operation mode becomes zero, the ON period of the first switch means is maximized, and the second switch means is turned off to shift to the first operation mode. It is possible to suppress the fluctuation of the output voltage that sometimes occurs.

According to the sixth aspect of the invention, by adding the time element to the switching condition of the two operation modes, the switching frequency of the second switch means can be reduced, so that the second switch is changed. The contact life can be extended when a relay is used as the means.

According to the invention of claim 7, the first
By providing the second ON period near the end of the energization section of the input current in addition to the ON period of, the energization angle of the input current can be further increased and the power factor can be further improved.

According to the eighth aspect of the present invention, the operation modes are switched at the time of zero crossing of the AC power supply, so that the operation modes can be smoothly switched without unnecessary short-circuit current flowing during the switching. You can

According to the tenth aspect of the present invention, by starting the first ON period after a lapse of a predetermined time from the zero cross, the improvement range of the input current waveform can be widened, and as a result, the harmonic regulation Can be made easier to clear.

According to the twelfth aspect of the invention, it is not necessary to temporarily switch the first switch means from on to off or from off to on at the time of switching the operation mode. Since it suffices to gradually increase or decrease the ON width of the switch means, the disturbance of the input current waveform at the time of mode switching can be suppressed more easily.

According to the fourteenth aspect of the invention, in the first operation mode, the increase / decrease amount of the ON width of the first switch means per power source half cycle is larger than the increase / decrease amount in the second operation mode. By setting a large value, the responsiveness of the output voltage to the target output voltage can be made substantially equal within the output voltage range.

According to the fifteenth aspect of the present invention, the second and third switching means are controlled to be off for a half cycle of the power supply voltage when the operation mode is switched.
Even when a relay having a large variation in operation time is used as the switch means, it is possible to prevent the output voltage from being disturbed due to the boosting action due to the short loop of the input power supply by preventing both the first and second from being turned on. Can be avoided.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining the concept of a power supply device according to the present invention.

FIG. 2 is a circuit diagram showing the configuration of the power supply device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating one operation mode (mode switching at a duty ratio of 100%) of the power supply device according to the first embodiment ((a) output voltage, (b) change of duty ratio of switch SW1, (c)). ON / OFF state of the switch SW2).

FIG. 4 is a diagram illustrating an operation mode 1 of the power supply device according to the first embodiment, on / off of switches and various waveforms (power supply voltage,
The figure showing the relationship with the output voltage, the waveform of the input current, etc. ((a) the waveform of the output voltage, (b) the control pulse of the switch SW1, (c) the control pulse of the switch SW2).

FIG. 5 is a diagram illustrating an operation mode 2 of the power supply device according to the first embodiment, on / off of switches and various waveforms (power supply voltage,
(Waveform of input current) showing the relationship ((a) waveform of input current, etc., (b) control pulse of switch SW1, (c))
Control pulse of switch SW2).

FIG. 6 is a diagram showing a waveform of an input current at the time of switching one operation mode of the power supply device according to the first embodiment ((a) a waveform of the input current or the like, (b) a change of the duty ratio of the switch SW1, c) ON / OFF state of the switch SW2).

FIG. 7 is a diagram illustrating another operation mode (mode switching at a duty ratio of 90%) of the power supply device according to the first embodiment ((a) output voltage, (b) change of duty ratio of switch SW1, (c)). ON / OFF state of the switch SW2).

FIG. 8 is a diagram showing waveforms of an input current when another operation mode of the power supply device according to the first embodiment is switched ((a) waveform of input current, (b) control pulse of switch SW1,
(C) ON / OFF state of the switch SW2).

FIG. 9 is a diagram for explaining one operation mode (mode switching at a duty ratio of 100%) of the power supply device according to the second embodiment ((a) output voltage, (b) change of duty ratio of switch SW1, (c)). Change in duty ratio of the switch SW2).

FIG. 10 is a diagram for explaining another operation mode (mode switching at a duty ratio of 90%) of the power supply device according to the second embodiment ((a) output voltage, (b) change of duty ratio of switch SW1, (c)). Change in duty ratio of the switch SW2).

FIG. 11 is a diagram illustrating two-pulse control in the power supply device according to the third embodiment ((a) waveform of input current, etc., (b) control pulse of switch SW1, (c) ON / OFF state of switch SW2).

FIG. 12 is a diagram showing a waveform of an input current at the time of switching one operation mode (switching from mode 1 to mode 2) of the power supply device according to the fourth embodiment ((a) a waveform of the input current,
(B) Change in duty ratio of the switch SW1, (c) ON / OFF state of the switch SW2).

FIG. 13 is a diagram showing a waveform of an input current at the time of switching one operation mode (switching from mode 2 to mode 1) of the power supply device according to the fourth embodiment ((a) a waveform of the input current,
(B) Change in duty ratio of the switch SW1, (c) ON / OFF state of the switch SW2).

FIG. 14 is a circuit diagram of a conventional power supply device.

[Explanation of symbols]

1 AC power supply 2 rectifier circuit 3 reactor 4, 5, 11 capacitors 8 load 12 Power phase detector 15 Output voltage detector 13 Pulse width controller 14 Relay ON / OFF control unit SW1, SW2 switch

Claims (15)

[Claims] 1. Having two inputs and two outputs,
A rectifier circuit that is connected to an AC power supply via a reactor and converts an AC power supply voltage into a DC voltage; and a capacitor circuit that includes a plurality of capacitors connected in series and that is connected between two output terminals of the rectifier circuit. A first connection connected between one input end of the rectifier circuit and one connection point between capacitors in the capacitor circuit
And a second switch means connected between the other input end of the rectifier circuit and the connection point between the capacitors in the capacitor circuit. 2. A control means for controlling the first and second switch means according to any one of the first and second operation modes, wherein the first operation mode is the first operation mode. Controlling the switch means to be continuously turned on only during a first on period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage, and to control the second switch means to be always off. In the second operation mode, the first switch means is controlled to be continuously turned on only during a first on period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage, 2. The power supply device according to claim 1, wherein the switch means is controlled to be always on. 3. The control means sets an operation mode used for controlling the first and second switch means from the first operation mode to the first operation mode when the first ON period becomes larger than a predetermined value. The power supply device according to claim 2, wherein the power supply device is switched to one of the two operation modes. 4. The control means sets an operation mode used for controlling the first and second switch means from the second operation mode to the first operation mode when the first ON period becomes zero. 3. The operation mode is switched to the operation mode.
The power supply described. 5. The control means sets the operation mode used for controlling the first and second switch means after the first ON period becomes zero and a predetermined time elapses in that state, and a second operation mode is set. 3. The power supply device according to claim 2, wherein the operation mode is switched to the first operation mode. 6. The control means switches from the second operation mode to the second operation mode when the control in the second operation mode continues for a predetermined time or more and the first ON period becomes zero. The power supply device according to claim 2, wherein the power supply device is switched to the operation mode 1. 7. The control means further comprises, in a half cycle of the power supply, a second ON period for turning on the first switch means, in addition to the first ON period. The power supply described. 8. The power supply device according to claim 2, wherein the control means performs on / off switching of the second switch means at a zero cross point of the power supply voltage. 9. The power supply device according to claim 2, wherein the control means starts the first ON period at a zero cross point of the power supply voltage. 10. The power supply device according to claim 2, wherein the control means starts the first ON period after a lapse of a predetermined time from a zero cross point of the power supply voltage. 11. The power supply device according to claim 1, wherein the second switch means is a relay. 12. A control means for controlling the first and second switch means according to any one of the first and second operation modes, wherein the first operation mode is the first operation mode. Controlling the switch means to be continuously turned on only during a first ON period that changes according to the output voltage of the power supply device in a half cycle of the power supply voltage, and to constantly turn off the second switch means. In the second operation mode, the first switch means is always turned on, and the second switch means is continuously turned on during a second ON period that changes in accordance with the output voltage of the power supply device in a half cycle of the power supply voltage. The power supply device according to claim 1, wherein the power supply device is controlled to be turned on manually. 13. A control means for controlling the first and second switch means according to any one of the first and second operation modes, wherein the first operation mode is the first operation mode. For switch means,
Pulse width control is performed with a cycle shorter than a half cycle of the power supply voltage as a carrier cycle, and the second switch means is controlled to be always off. In the second operation mode,
2. The power supply device according to claim 1, wherein pulse width control is performed in the carrier period to constantly control the second switch means. 14. The control means sets, in the first operation mode, an increase / decrease amount of the first ON period per half cycle of a power supply voltage to be larger than an increase / decrease amount in the second operation mode. The power supply device according to claim 2, wherein 15. The control means includes the first or second device.
Of one of the operation modes, the operation is performed after providing a period for controlling both the first and second switch means to be off for a half cycle or more of the power supply voltage when switching from the one operation mode to the other operation mode. The power supply device according to claim 2, wherein the mode is switched.