JP3753823B2 - Power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply device that improves a power factor by short-circuiting a power supply through a reactor connected in series with the power supply, and more particularly to a power supply device that can operate at high speed and has excellent controllability.
[0002]
[Prior art]
In order to extract more active power from the power supply device, it is effective to improve the power source power factor, and the maximum capacity of the device can be increased by supplying more active power to the load device. Further, by improving the power source power factor, it is often possible to reduce the harmonic current of the power source, which has become a problem in recent years, and it is possible to meet domestic and foreign harmonic current regulations.
[0003]
As a method for improving the power factor of the power supply device, there is a conventional method disclosed in, for example, Japanese Patent Application Laid-Open No. 7-7946. In this publication, the power supply is short-circuited through a reactor by a short-circuit element. Specifically, the short-circuit of the reactor is started according to the load state, short-circuit current, harmonic current content rate, power source power factor, waveform distortion factor, etc. Delay time and short-circuit period are determined.
[0004]
[Problems to be solved by the invention]
In the conventional method for improving the power factor of the power supply device, there is no description about generation of a short-circuit pulse in a transient state when starting the power factor correction operation or ending the power factor correction operation. At the start or end of the power factor correction operation, there is a problem that the operation becomes unstable due to vibration, sudden increase or decrease in output voltage, and adversely affects the operation of the load.
[0005]
The present invention has been made in view of the above, and an object of the present invention is to provide a power supply apparatus in which the operation at the start or end of the power factor correction operation is stabilized and the reliability is improved.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention according to claim 1 provides:Rectifying means for rectifying an AC voltage from an AC power supply into a DC voltage, a reactor connected in series to the rectifying means, a short-circuit means for short-circuiting the AC power supply via the reactor, and driving the short-circuit means to a short-circuit state A power supply device having a short-circuit pulse generating means for generating a short-circuit pulse for controlling the short-circuit pulse generating means to gradually reduce the width of the short-circuit pulse at the end of the generation of the short-circuit pulse The gist is to have means.
[0011]
  Claim1In the described invention, since the width of the short-circuit pulse is gradually reduced at the end of the generation of the short-circuit pulse, it prevents a sudden increase in the DC output voltage, a sudden change in the power supply current or the DC output voltage, and stable operation. It can be carried out.
[0012]
  Claim2The invention as described is claimed.1In the described invention, the load level of the AC power supply isWhere the load level is lower than the load level at the end of generation of the short-circuit pulseWhen the load level is smaller than a predetermined load level, there is an immediate end control means for controlling the short-circuit pulse generating means so as to immediately stop the generation of the short-circuit pulse.To doAnd the gist.
[0013]
  Claim2In the present invention described, the load level isSaidWhen the load level is lower than the predetermined load level, the generation of the short-circuit pulse is immediately terminated, so that a sudden increase in the DC output voltage can be prevented and the load can be protected from overvoltage.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a diagram showing a circuit configuration of a power supply device according to the first embodiment of the present invention. The power supply device shown in FIG. 1 has a reactor 2 having one end connected to one output end of an AC power supply 1, and the other end of the reactor 2 includes a first diode bridge 3 constituting a full-wave rectifier and Each of the second diode bridges 9 having the same current direction is connected to one input terminal. The other input terminal of each of the first and second diode bridges 3 and 9 is connected to the other output terminal of the AC power supply 1.
[0016]
The output terminal of the first diode bridge 3 is connected to the load 7 via the smoothing electrolytic capacitors 4, 5, 6, whereby the AC voltage from the AC power source 1 is converted into the first diode bridge 3 and the smoothing electrolytic capacitor 4. , 5 and 6 are double voltage rectified and supplied to the load 7 as a DC voltage.
[0017]
Both output ends of the second diode bridge 9 are connected between the collector and the emitter of the short-circuit element 10 which is a switching element made of, for example, an IGBT, a bipolar transistor, a MOSFET or the like. The AC power supply 1 is short-circuited through the diode bridge 9 and the reactor 2 so that the power factor of the power supply device can be improved. The gate of the short-circuit element 10 is connected to the power factor improvement control means 13, and the short-circuit element 10 is turned on when the short-circuit element 10 is driven by the power factor improvement control means 13.
[0018]
Also, zero cross detection means 12 is connected to both output terminals of the AC power supply 1, and the zero cross detection means 12 detects the time when the AC voltage of the AC power supply 1 passes through the zero cross point, and this detection signal is used as the power factor improvement control means. 13 is supplied. A control circuit 11 is configured by the zero-cross detection unit 12 and the power factor improvement control unit 13, and the control circuit 11 is configured by, for example, a microcomputer. The power factor correction control means 13 is input with the load level of the power supply device.
[0019]
FIG. 2 is a diagram showing a circuit configuration of a power supply device according to the second embodiment of the present invention. The power supply device shown in FIG. 1 has one end of a reactor 2 connected to one output end of a first diode bridge 3 that performs full-wave rectification of the AC voltage of the AC power source 1, and the other end of the reactor 2 and a first diode. When the collector and the emitter of the short-circuit element 10 formed of a switching transistor are connected between the other output terminal of the bridge 3 and the short-circuit element 10 is turned on, the AC power source 1 is connected via the reactor 2 and the first diode bridge 3. Are configured to be short-circuited. The other end of the reactor 2 is connected to a smoothing electrolytic capacitor 6 and a load 7 via a backflow preventing diode 15. The diode 15 acts so that the capacitor 6 is not short-circuited when the short-circuit element 10 is turned on and the AC power supply 1 is short-circuited via the reactor 2 and the first diode bridge 3.
[0020]
As in the power supply apparatus of FIG. 1, the zero cross detection means 12 is connected to the AC power supply 1, and the power factor correction control means 13 is connected to the gate of the short-circuit element 10, and these zero cross detection means 12 and The power factor improvement control means 13 has the same function and configuration as shown in FIG.
[0021]
FIG. 3 is a functional configuration diagram for easily explaining the operation principle of the power supply device shown in FIGS. 1 and 2 described above, and particularly shows the internal configuration of the control circuit 11. As shown in FIG. 3, the control circuit 11 of the power supply apparatus shown in FIGS. 1 and 2 includes a zero-cross detection means 12 and a power factor improvement control means 13. The power factor improvement control means 13 determines the load level. A load level determination unit 31; a start / end processing unit 32 that controls processing at the start and end of the power factor improvement operation; and a steady processing unit 33 that performs steady power factor improvement processing. A short-circuit pulse is supplied from the means 33 to the short-circuit element 10.
[0022]
Next, referring to FIG. 4, the operation of the power supply devices of the first and second embodiments shown in FIGS. 1 and 2 will be described. In FIG. 4, 21 is the waveform of the AC voltage of the AC power supply 1, 22 is the waveform of the short-circuit pulse supplied from the power factor correction control means 13 to the short-circuit element 10, and 23 is the power factor improvement control means 13. The load level supplied to is shown as an analog value.
[0023]
When an AC voltage having a sinusoidal waveform as indicated by 21 in FIG. 4 is input from the AC power source 1, this AC voltage is supplied from the first diode bridge 3 and the capacitors 4, 5, 6 via the reactor 2 in FIG. The voltage doubler rectifier circuit is converted to a DC voltage and supplied to the load 7. In FIG. 2, the AC voltage from the AC power source 1 is full-wave rectified by the first diode bridge 3, smoothed by the capacitor 6 through the reactor 2 and the diode 15, and supplied to the load 7 as a DC voltage. The In this case, the zero cross detection means 12 monitors the AC voltage from the AC power source 1 and detects the zero cross point, and supplies this detection signal to the power factor correction control means 13.
[0024]
In such a state where the DC voltage is supplied to the load 7, a load level as indicated by reference numeral 23 in FIG. 4 is supplied to the load level determination means 31 of the power factor correction control means 13. The load level determination unit 31 compares the load level with the first predetermined load level A. When the load level becomes higher than the first predetermined load level A, the load level determination unit 31 drives the start / end processing unit 32 to start / end. Under the control of the processing means 32, a short-circuit pulse as indicated by 22 in FIG. 4 is generated from the steady-state processing means 33 according to the zero-cross point detection signal from the zero-cross detection means 12, and the short-circuit pulse is supplied to the short-circuit element 10.
[0025]
When the short-circuit pulse 22 is supplied to the short-circuit element 10, the short-circuit element 10 is turned on in response to the short-circuit pulse 22, whereby the AC power supply 1 is turned on via the second diode bridge 9 and the reactor 2 in FIG. When the AC power supply 1 is short-circuited through the reactor 2 and the first diode bridge 3 in FIG. 2 and when the short-circuit pulse disappears and the short-circuit element 10 is opened in the OFF state, the short-circuit element 10 is accumulated. Energy is released to the load side. By short-circuiting the AC power supply 1 through the reactor 2 in this way, the power supply current also flows in the phase section of the power supply where the current did not flow conventionally, and the current conduction time is expanded, thereby reducing the power factor. Can be improved.
[0026]
The load level determination means 31 monitors the load level, and when the load level becomes lower than the second predetermined load level B as shown in FIG. 4, the start / end processing means 32 is driven to start / The generation of the short-circuit pulse from the steady processing means 33 is stopped by the control of the end processing means 32, thereby ending the power factor improvement processing.
[0027]
As described above, in this embodiment, the load level is monitored, and when the load level is low, the power factor improvement processing is not performed. However, this is because the power factor improvement operation is performed when the load level is small. Even so, the effect of improving the power factor is small, and on the contrary, the current waveform is distorted to prevent adverse effects.
[0028]
In the above-described processing, by setting the first predetermined load level A higher than the second predetermined load level B (A> B), the timing at which the start and end of the power factor improvement processing is switched. It is possible to prevent oscillation of the power factor improving operation. In this case, the hysteresis width is set so that the load can be stably operated from the characteristics of the load, the boosting characteristics of the power supply device, the response time of the power supply device and the load, and the like. Depending on the configuration of the power supply device, the second predetermined load level B may be set to almost zero, and even in such a case, the effect can be sufficiently exhibited.
[0029]
The power supply device having the power factor improvement function of the present invention has a boosting function, and when the power factor improvement process is performed, the DC output voltage of the power supply device increases compared to the state immediately before the power factor improvement. The effective value of the power supply current is reduced. For this reason, when the load is an electric motor or the like, if there is no hysteresis, the speed of the electric motor vibrates and an unstable operation occurs, and the operation may stop depending on the case. However, in the power supply device of the present invention, since the power factor correction operation does not frequently switch at the load level near the start and end of the power factor improvement process, the DC output voltage oscillates, The power supply current and the DC output voltage do not vibrate, and even if the power factor is improved, the DC output voltage gradually rises, and a stable operation can always be performed continuously.
[0030]
In each of the above embodiments, specifically, the load level is, for example, power supply current, load current, output current, power factor, harmonic current, distortion factor, load control parameter, for example, the rotation speed detected from the load, Various parameters that can determine the magnitude of the load such as speed, temperature, humidity, pressure, weight, etc. can be utilized.
[0031]
Next, a power supply device according to a third embodiment of the present invention will be described with reference to FIGS.
[0032]
FIG. 5 is a functional configuration diagram of a main part for easily explaining the operation principle of the power supply device according to the third embodiment. The specific circuit configuration is the power source of any of the circuit configurations shown in FIG. 1 and FIG. The apparatus can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the operation of the third embodiment will be described with reference to FIG.
[0033]
As shown in FIG. 5, the power supply device of the third embodiment is different from that of the first and second embodiments shown in FIG. It is the same as that of FIG.
[0034]
That is, the power factor improvement control unit 13 shown in FIG. 5 includes a load level determination unit 31 that determines the load level, a start processing unit 34 that controls processing at the start of the power factor improvement operation, and a steady power factor improvement process. The start processing means 34 is provided in place of the start / end processing means 32 in FIG.
[0035]
The start processing means 34 generates a short-circuit pulse 24 whose pulse width gradually increases from a small pulse width to a large pulse width as shown by 24 in FIG. 6 when the short-circuit pulse starts to be supplied to the short-circuit element 10. Is. In FIG. 6, 21 indicates the waveform of the AC voltage of the AC power supply 1, 24 indicates the waveform of the short-circuit pulse whose pulse width gradually changes greatly, and 25 indicates the load level as an analog value.
[0036]
FIG. 7 shows the direct-current output voltage of the power supply apparatus that changes corresponding to the short-circuit pulse 24 whose pulse width gradually increases as described above, indicated by a solid line with reference numeral 42, and in the case where only the conventional steady processing is performed. A change in the DC output voltage is indicated by reference numeral 41 by a dotted line. As shown in FIG. 7, the DC output voltage gradually increases by gradually increasing the width of the short-circuit pulse as in this embodiment, whereas the pulse width is gradually increased as in the prior art. When the short-circuit pulse having the normal pulse width is suddenly supplied from the steady process, the DC output voltage is suddenly increased.
[0037]
More specifically, in the third embodiment shown in FIG. 5, the load level determination means 31 monitors the load level of the power supply device, and the load level becomes higher than a predetermined power factor improvement level, thereby improving the power factor. When it is detected that the process has started, the start processing means 34 is driven to generate a short-circuit pulse whose pulse width gradually changes as shown by 24 in FIG. The AC power supply 1 is short-circuited through the reactor 2 by this, and the power factor correction process is started.
[0038]
Then, when the pulse width of the short-circuit pulse gradually increases and becomes equal to the pulse width originally output by the steady processing means 33, the load level determination means 31 replaces the start processing means 34 with the steady processing means 33. Is driven to generate a short-circuit pulse having a predetermined pulse width in a steady state from the steady-state processing means 33, and the short-circuit element 10 is driven by the short-circuit pulse in the steady state to perform a steady-state power factor improvement process. In FIG. 6, the number of short-circuit pulses is reduced for simplification.
[0039]
Note that the speed at which the pulse width of the short-circuit pulse is gradually increased is set to a value that allows stable operation from the characteristics of the load, the boosting characteristics of the power supply device, the response time of the power supply device and the load, and the like. Specifically, the pulse width of the short-circuit pulse is increased for each pulse at a speed of, for example, around 1 μS / 10 mS to about 50 μS / 10 mS or slower. Note that 10 mS is ½ of the cycle of the AC power supply 1 when the frequency of the AC power supply 1 is 50 Hz.
[0040]
The power supply device having the power factor improvement function of the present invention has a boosting function, and when the power factor improvement process is performed, the DC output voltage of the power supply device increases compared to the state immediately before the power factor improvement. The effective value of the power supply current is reduced. If a short-circuit pulse for power factor improvement is immediately output with a predetermined pulse width as in the prior art, the DC output voltage rises rapidly, and the load current suddenly drops. For this reason, when the load is an electric motor or the like, the speed rapidly increases and the operation becomes unstable, and in some cases, the load may stop. However, in the power supply device of the present invention, since the width of the short-circuit pulse for power factor improvement gradually increases, the DC output voltage does not rise rapidly, and the power source current and the DC output voltage do not change suddenly. Even when the improvement operation is started, a stable operation can be continuously performed.
[0041]
In the present embodiment, when the load level is monitored by the load level determination unit 31, a short-circuit pulse is generated when the load level exceeds a predetermined level, a power factor correction operation is performed, and the load level is small. Does not perform the power factor improvement process, but even if the power factor improvement operation is performed when the load level is small, the power factor improvement effect is small, and on the contrary, the current waveform is distorted and adversely affected. This is to prevent that sometimes occurs. However, a short-circuit pulse is generated from a state in which the load level is almost zero (in this case, the short-circuit pulse may have a short pulse width so as not to be effective in improving the power factor), or a short-circuit pulse is generated at the same time as the power supply device is started It is clear that the present embodiment can also exert the same effect when outputting.
[0042]
Next, a power supply device according to a fourth embodiment of the present invention will be described with reference to FIGS.
[0043]
FIG. 8 is a functional configuration diagram of a main part for easily explaining the operation principle of the power supply device according to the fourth embodiment, and a specific circuit configuration thereof is a power source of any one of the circuit configurations shown in FIGS. 1 and 2. The apparatus can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the operation of the fourth embodiment will be described with reference to FIG.
[0044]
As shown in FIG. 8, the power supply device of the fourth embodiment is different from that of the third embodiment shown in FIG. 5 in the configuration of the power factor correction control means 13, and other configurations and operations are the same as those in FIG. Is the same.
[0045]
That is, the power factor improvement control unit 13 shown in FIG. 8 includes a load level determination unit 31 that determines a load level, an end processing unit 35 that controls processing at the end of the power factor improvement operation, and a steady power factor improvement process. And an end processing means 35 instead of the start processing means 34 in FIG.
[0046]
At the end of generation of the short-circuit pulse supplied to the short-circuit element 10, that is, at the end of the power factor correction process, the end processing unit 35 has a pulse width that is smaller than the large pulse width at the time of steady processing as indicated by 26 in FIG. The short-circuit pulse 26 that gradually decreases to the pulse width is generated. In FIG. 9, 21 indicates the waveform of the AC voltage of the AC power supply 1, 26 indicates the waveform of the short-circuit pulse whose pulse width gradually changes, and 27 indicates the load level as an analog value.
[0047]
FIG. 10 shows the direct-current output voltage of the power supply apparatus that changes in response to the short-circuit pulse 26 whose pulse width gradually changes as described above, indicated by a solid line 44, and when only the conventional steady processing is performed. The change in the DC output voltage is indicated by a dotted line 43 by a dotted line. As shown in FIG. 10, the DC output voltage is gradually reduced by gradually reducing the width of the short-circuit pulse as in the present embodiment, whereas the pulse width is gradually reduced as in the prior art. It can be seen that when the supply of the short-circuit pulse is suddenly stopped from the steady process without reducing the DC output voltage, the DC output voltage is suddenly reduced.
[0048]
More specifically, in the fourth embodiment shown in FIG. 8, when the load level determination means 31 monitors the load level 27 of the power supply device and detects that the load level is lower than a predetermined level, the process is terminated. The processing means 35 is driven to generate a short-circuit pulse whose pulse width gradually changes as indicated by 26 in FIG. 9, and the short-circuit element 10 is driven by this decreasing short-circuit pulse. The AC power supply 1 is short-circuited. Then, when the pulse width of the short-circuit pulse becomes almost zero, the generation of the short-circuit pulse is finished, and the power factor improvement process is finished. In FIG. 8, the number of short-circuit pulses is reduced for simplification.
[0049]
The speed at which the pulse width of the short-circuit pulse is gradually reduced is set to a value that allows stable operation from the load characteristics, the boosting characteristics of the power supply device, the response time of the power supply device and the load, and the like. Specifically, the pulse width of the short-circuit pulse is reduced for each pulse at a speed of, for example, about 1 μS / 10 mS to about 50 μS / 10 mS or slower.
[0050]
The power supply device having the power factor correction function of the present invention has a boosting function. When the power factor correction process is stopped, the DC output voltage decreases compared to the state immediately before the power factor correction is performed, and the power source current Rises. For this reason, when the load is an electric motor or the like, the speed is suddenly reduced and the operation becomes unstable, and in some cases, the load may stop. However, in the power supply device of the present invention, since the width of the short-circuit pulse for power factor improvement is gradually reduced, the DC output voltage does not rise rapidly, and the power supply current and the DC output voltage do not change suddenly. Even after the improvement operation is finished, the DC output voltage gradually decreases, and a stable operation can be continuously performed.
[0051]
In the present embodiment, the load level is monitored by the load level determination means 31. When the load level is small, no short circuit pulse is output, and therefore the power factor correction processing is not performed. Even if the power factor improvement operation is performed when the load level is small, the power factor improvement effect is small, and on the contrary, the current waveform is distorted to prevent adverse effects. However, it is clear that the same effect can be exhibited even if the processing as in the present embodiment is performed when the load level becomes almost zero.
[0052]
Next, a power supply device according to a fifth embodiment of the present invention will be described with reference to FIGS.
[0053]
FIG. 11 is a functional configuration diagram of a main part for easily explaining the operation principle of the power supply device according to the fifth embodiment, and a specific circuit configuration thereof is a power source of any one of the circuit configurations shown in FIGS. 1 and 2. The apparatus can be similarly implemented. Since the circuit configuration of the power supply device shown in FIGS. 1 and 2 has already been described in detail, the operation of the fifth embodiment will be described with reference to FIG.
[0054]
As shown in FIG. 11, the power supply device of the fifth embodiment is different from the fourth embodiment shown in FIG. 8 in that the configuration of the power factor correction control means 13 is different from that of the fourth embodiment shown in FIG. The configuration and operation of are the same as those of FIG.
[0055]
That is, in FIG. 11, the newly added emergency stop processing means 36 suddenly and suddenly has a load level at the end of the power factor correction process in which the end processing means 35 gradually reduces the pulse width of the short-circuit pulse. When the voltage decreases and becomes lower than a predetermined level, the generation of a short-circuit pulse is stopped, and the power factor correction process is stopped suddenly.
[0056]
FIG. 12 shows this state. In FIG. 12, 21 indicates the waveform of the AC voltage of the AC power supply 1, and 28 indicates the waveform of the short-circuit pulse whose pulse width gradually changes at the end of the power factor improvement. , 29 indicates the load level as an analog value, and it is indicated that the load level 29 rapidly decreases in the middle and is reduced to a level lower than the predetermined load level C.
[0057]
More specifically, in the fifth embodiment shown in FIG. 11, the load level determination means 31 monitors the load level 29 (FIG. 12) of the power supply device, and the load level becomes smaller than a predetermined level. When detected, the termination processing means 35 is driven to generate a short-circuit pulse whose pulse width gradually changes as indicated by 28 in FIG. 11, and the short-circuit element 10 is driven by this decreasing short-circuit pulse. As a result, the AC power supply 1 is short-circuited through the reactor 2.
[0058]
In the middle of this operation, when the load level suddenly drops as shown by 29 in FIG. 12 and becomes lower than a predetermined load level C, the load level determination means 31 makes the load level 29 sudden. Thus, the emergency stop processing means 36 is driven. As a result, the emergency stop processing means 36 controls the end processing means 35 so as to stop the generation of the short-circuit pulse by the end processing means 35, thereby ending the power factor improving operation.
[0059]
The predetermined load level C is set to a value that can protect the load from the allowable voltage range of the load, the boosting characteristics of the power supply circuit, the response time of the power supply circuit and the load, and the like. As a result of such processing, it is possible to prevent an abnormal DC voltage increase and protect the load from overvoltage, and a more reliable power supply device can be realized.
[0060]
In each of the above embodiments, a power supply device having the same power factor improvement function and the same effect can be configured even if the connection positions of the respective components such as the reactor, the short circuit, the capacitor, and the rectifier circuit are switched. Thus, the present invention can be similarly applied to various power supply devices that have been replaced and changed in this way.
[0061]
In each of the above embodiments, the number of short-circuit pulses has been described as being one. However, even when two or more short-circuit pulses are used, the same effect as the present invention can be achieved. is there. For example, when the number of short-circuit pulses is two, a method of expanding or narrowing the width of two short-circuit pulses simultaneously, a method of expanding or narrowing the width of one short-circuit pulse of two short-circuit pulses, or the like. Or the like, the width of the other short-circuit pulse may be widened or narrowed.
[0062]
【The invention's effect】
  As described above, according to the present invention described in claim 1,Since the width of the short-circuit pulse is gradually reduced at the end of the generation of the short-circuit pulse, it is possible to prevent a sudden increase in the DC output voltage and a sudden change in the power supply current or the DC output voltage, and a stable operation can be performed.
[0065]
  Claim2According to the described invention, when the load level is smaller than the third predetermined load level at the end of the generation of the short-circuit pulse, the generation of the short-circuit pulse is immediately ended, so that an abrupt increase in the DC output voltage is prevented. The load can be protected from overvoltage.
[Brief description of the drawings]
FIG. 1 is a diagram showing a circuit configuration of a power supply device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a circuit configuration of a power supply device according to a second embodiment of the present invention.
FIG. 3 is a functional configuration diagram for easily explaining the operation principle of the power supply device shown in FIGS. 1 and 2;
FIG. 4 is an operation waveform diagram for explaining the operation of the power supply devices of the first and second embodiments shown in FIGS.
FIG. 5 is a functional configuration diagram of a main part for easily explaining an operation principle of a power supply device according to a third embodiment of the present invention.
6 is an operation waveform diagram for explaining the operation of the power supply device shown in FIG. 5;
7 is an operation waveform diagram for explaining the operation of the power supply device shown in FIG. 5. FIG.
FIG. 8 is a functional configuration diagram of a main part for easily explaining an operation principle of a power supply device according to a fourth embodiment of the present invention.
FIG. 9 is an operation waveform diagram for explaining the operation of the power supply device shown in FIG. 8;
10 is an operation waveform diagram for explaining the operation of the power supply device shown in FIG.
FIG. 11 is a functional configuration diagram of a main part for easily explaining an operation principle of a power supply device according to a fifth embodiment of the present invention.
12 is an operation waveform diagram for explaining the operation of the power supply device shown in FIG.
[Explanation of symbols]
1 AC power supply
2 reactors
3 First diode bridge
4, 5, 6 capacitors
7 Load
9 Second diode bridge
10 Short-circuit element
11 Control circuit
12 Zero cross detection means
13 Power factor improvement control means
31 Load level judgment means
32 Start / end processing means
33 Regular processing means
34 Start processing means
35 End processing means
36 Emergency stop processing means

Claims (2)

Rectifying means for rectifying an AC voltage from an AC power supply into a DC voltage, a reactor connected in series to the rectifying means, a short-circuit means for short-circuiting the AC power supply via the reactor, and driving the short-circuit means to a short-circuit state A power supply device having a short-circuit pulse generating means for generating a short-circuit pulse for
A power supply apparatus comprising: a pulse width reduction control unit that controls the short-circuit pulse generation unit so that the width of the short-circuit pulse is gradually reduced at the end of the generation of the short-circuit pulse. When the load level of the AC power supply is less than the smaller at constant load level than the load level at completion of generation of the short pulse, immediately to control the short pulse generating means to immediately terminate the generation of the short pulse power supply according to claim 1, wherein Rukoto to have a termination control means.

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