JPH01215465A - Arc power unit - Google Patents

Abstract

PURPOSE:To improve operability and utilizing efficiency of input AC and to dissolve waveform distortion of the input AC by providing specifically an input rectification part, a reactor, a switching element and a smoothing capacitor part, a voltage detector and a control part. CONSTITUTION:The 100 or 200V power source AC inputted to terminals 1 and 2 is rectified by a rectifier 26. In addition, a transistor 28 executes high-frequency switching with frequency higher sufficiently than the power source AC by a driving signal of an active filter control circuit 34. During an on period of time of the transistor 28, a current of the rectified output is then carried to it via the reactor 27 and the polarity energy in the arrow direction is accumulated on the reactor 27 and the reversed polarity voltage is generated during an off period of time of the transistor 28. At this time, capacitors 37 and 38 are charged and the smoothing voltage between connecting points P and N between both ends of both of these capacitors is detected by the detector 33 and a voltage detection signal in proportion to the smoothing voltage is outputted to the control circuit 34 from the detector 33.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc power supply device installed in an arc device that can be driven with a plurality of input alternating currents having different voltages.

[Conventional technology]

Conventionally, arc equipment such as arc welders and arc cutters that can be driven with either 100 V or 200 V commercial AC power supply has been equipped with an arc device having the configuration shown in Fig. 2 as a constant current control type DC power supply. A power supply is provided.

In addition, in Figure 2, (1) and (2) are 100
It consists of a two-contact changeover switch having a pair of AC input contacts (b) and (b) connected to a single-phase AC power supply of V or 200V, and the switching piece is connected to the input terminal (1).

(5), (6), (7), and (8) are four diodes that rectify the input AC of input terminals (1) and (2). The anode of (6) is connected to the input terminal (1),
the cathode of the diode (7) is connected to the cathode of the diode (6), and the anode of the diode (7);
The connection point of the diode to the anode of the diode (5) is connected to the contact (b) of the switch (3).

It forms an input side rectifier that performs 100v voltage double rectification and 200v full-wave rectification.

(9) and Qt) are two smoothing capacitors connected in series, and the series circuit of both capacitors (9) and QO is provided in parallel with the series circuit of diodes (7) and (8), and The connection point of the single capacitor (9) and α0 is connected to the contact (a) of the switch (3). αD,
(6) is a capacitor (9).

These are two pressure equalizing resistors provided in parallel to each of the 00 and 00, and form an input side smoothing circuit together with the capacitor (9) and GO.

Q3 and α→ are two NPN type switching transistors, the emitter of transistor (to) and the collector of transistor Q41 are connected, and the collector of transistor α is connected to the cathode of diodes (6) and (7). connected to the connection point p, and the transistor α
The emitter of 4) is connected to the connection point n of the anodes of diodes (5) and (8).

QG is a transformer for high frequency output equipped with a primary winding (15a) and a secondary winding with an intermediate tap (15b), and one end of the primary winding (15a) is connected to a capacitor CLQ for DC removal.
The other end of the primary winding (151) is connected to the connection point of the transistor (to) and α→ through the capacitor (
9) , (connected to 10 connection points.

qη and cn are two diodes forming an output rectifier, and their anodes are connected to both ends of the secondary winding (15b), respectively. One end of α is a smoothing glue act connected to the cathode of diode αη, (g), (7)
The workpiece connected to the other end of the beam handle Ql, Q])
is the torch electrode that forms an arc load with the workpiece (e), and the secondary winding (15b) is connected via the current detector @
connected to the middle tap.

Kanha transistor (to), 1~20KH at the pace of α Xun
This is an inverter drive circuit that outputs a drive signal for high-frequency switching of (to).

The start and end of the drive control of the transistor Q3 is controlled based on the detection signal from the detector.

By controlling the switching of α→, the load current flowing through the arc load is feedback-controlled to a constant current.

(E) is a power transformer for a drive circuit equipped with a primary winding (25a) and a secondary winding (25b) with an intermediate tap, and one end of the primary winding (25a) has an intermediate tap. switch(
4) are connected to the contacts (a)' and (b)' respectively, and the other end of the primary winding (25a) is connected to the input terminal (2), and both ends of the secondary winding (25b) is connected to the drive circuit ■.

Based on the input AC of 100 V and 200 V supplied to the input terminals (1) and (2), in advance,
Switches (3) and (4) are set to contact (
a), <d or contact (b).

(It can be switched to b.

That is, when the input AC is a power supply AC of 100V, the switches (3) and (4) are switched to the contacts (a) and <af, and the input AC is connected to the diodes (5) and (6).
and a capacitor (9).

The full wave type double voltage rectification of aO doubles the voltage and converts it into direct current, and between the connection points p and n (100VX, l'f
During X 2) a DC voltage of 290 V is generated.

Then, the DC voltage between the connection points p and n is the transistor □□
When the transistor is applied to the series circuit of □ and α, and the drive signal of 04 is applied to the series circuit of is applied.

Furthermore, high frequency alternating current is induced in the secondary winding (15b) based on the high frequency voltage applied to the primary winding (15a), and the high frequency alternating current in the secondary winding (15b) is caused by the diode aηl Ql191 reactor μσ groaning. The DC output is rectified and smoothed by the DC output, and is supplied to the workpiece and the arc load of the torch electrode.

The load current flowing through the arc load is still detected by the detector (c), and a detection signal proportional to the load current is output from the detector to the drive circuit (to).

By the way, the drive circuit operates based on the output alternating current of the secondary winding (25b), and starts drive control of the transistor (to) and QΦ upon input of a contact signal for starting the switch. .

Then, in order that the detection signal of the detector wire matches the internally set reference signal, the drive circuit is connected to a trans-shifter (to),
By controlling the switching frequency of α, the load current is feedback-controlled to a constant current.

On the other hand, when the input AC is a 200V power supply AC, switches (3) and (4) are switched to contacts (b) and (b)', and the input AC is full-wave rectified by the diodes (5) to (8). and capacitor (9), converted to DC by smoothing Ql, and in this case also, (200
During VX v'T) a DC voltage of 290V is generated.

Then, using the transistors α and α, the transformer α, the diode aη, the α frame, the reactor/I/a*, the detector, and the drive circuit, the arc load is applied in the same way as in the case of too v power supply AC. DC output is provided.

In addition, by switching the switch (4) to the contact rbf, an AC of the same voltage as in the case of a 100V power supply AC is generated in the secondary winding (25b), and an output AC of the rated voltage is supplied to the drive circuit @. , the drive circuit (goods) operates normally.

In addition, based on the contact signals of the start and stop operations of the switch, the start and stop of control of the transistors and α fathoms by the drive circuit are controlled, and the DC supply to the load is controlled.

Further, a conventional arc power supply device provided as a constant voltage control type DC power supply device is formed by replacing the detector (E) in FIG. 2 with a voltage detector.

[Problem to be solved by the invention]

By the way, in the case of the conventional arc power supply device.

It is necessary to change the operation switches such as switches (3) and (4) according to the input AC voltage, which requires a cumbersome operation and, for example, when the input AC is 200 V, it is necessary to change the operation switches (3) and (4) etc. Contact (a), (a
)', there is a problem that each circuit part of the device will be damaged due to high input voltage.

In addition, in the case of an input AC of 100V, double voltage rectification is performed with a capacitor input type configuration, and at this time, based on the charging and discharging of the capacitor, only the approximately positive and negative peak level portions of the input AC of the sine waveform are Capacitor (9),
Even if the conversion efficiency is increased by converting QO to high-frequency AC, for example, when inputting a small-capacity 100V single-phase AC power supply, sufficient DC cannot be supplied to the arc equipment, There is a problem that the power factor of the device becomes low, and furthermore, there is a problem that waveform distortion of the input AC occurs, which adversely affects other devices that operate on the same AC power source.

The present invention provides an arc power supply device that improves operability by omitting switching operations depending on the input AC voltage, improves the utilization efficiency of the input AC, and eliminates waveform distortion of the input AC. is intended to provide.

[Means to solve the problem]

Means for achieving the above object will be explained below with reference to FIG. 1, which corresponds to an embodiment.

The present invention provides a rectifier as an input rectifier that rectifies input AC and converts it into DC, a reactor/L/@ provided in series between the DC output terminal of the rectifier (E), and a semiconductor switching element as a rectifier. ) and the reactor /L/
A smoothing capacitor section into which the voltage at the connection point between @ and the transistor (to) is injected through a diode wire for backflow prevention... and a high-frequency converter that converts the smoothed output of the smoothing capacitor section (to) into high-frequency alternating current. part 01), and an output rectifying and smoothing part CI? which rectifies and smoothes the high frequency alternating current and supplies it to the arc load. between J and a voltage detector for detecting the smoothed voltage of the capacitor section (to), and supplying a drive signal for high frequency switching to the transistor (goods) based on the detection signal of the detector 1331 and the reference signal, The present invention provides an arc power supply device characterized by comprising an active filter control circuit as a control section that controls the smoothed voltage at a constant voltage.

[For production]

Therefore, based on the detection signal of the detector (33), the switching frequency of the transistor wire is varied and the smoothed voltage of the capacitor section (7) is controlled at a constant voltage, so that the smoothed voltage is kept at a constant voltage regardless of the input AC voltage. Based on the smoothed output of the constant voltage, the converting section Yu, the rectifying and smoothing section I3
DC output is supplied to the arc load by the operation in step 2.

Then, due to the charging and discharging of the reactor based on the high frequency switching of the transistor (e), the accumulated energy of the reactor/L/@ is superimposed on the rectified output of the rectifier and is repeatedly injected into the capacitor section (to). , the capacitor section (7) is repeatedly charged during the entire period of input AC, improving the utilization efficiency of input AC.

Moreover, due to the high frequency switching of the transistor wire, the input alternating current constantly flows through the device via the rectifier, thereby preventing waveform distortion of the input alternating current.

〔Example〕

Next, one embodiment of the present invention will be explained in detail with reference to FIG. 1 showing one embodiment thereof.

In Fig. 1, the same symbols as in Fig. 2 indicate the same ○, and the upper part is a rectifier that rectifies the input AC of input terminals (1) and (2), and is composed of a full-wave or half-wave diode rectifier. , form the input → rectifier section, and output the rectified output according to the input AC to the positive and negative output terminals (G).

(The output is from →. The slope and @ are the output terminals ←) and the transistor e!, which is connected in series between 0 and 0, is an NPN type switching transistor, and forms a semiconductor switching element. The collector marked with a mark is connected to the output terminal (G) via a reactor slope, and the emitter of the transistor wire is connected to the output terminal (←) via a current detector +351. (To) is a surge absorption capacitor that is installed in parallel to the series circuit of reactor/L/■, transistor (To), and detector (351).

The 7th node of the wire is a backflow prevention diode connected to the connection point between the reactor lv@ and the collector of the transistor wire.
(3η, (381 is 2 for smoothing that forms the smooth part (to)
A capacitor is installed in series between the cathode of the diode and the emitter of the transistor.
Connection point P between the cathode of the diode wire and the capacitor aη
is connected to the collector of the transistor (14), and the connection point N between the capacitor and the emitter of the transistor (14) is connected to the emitter of the transistor (14). (&
A voltage detector 1 is provided between the connection points P and N, and outputs a voltage detection signal proportional to the smoothed voltage between the connection points P and N.

139) is a DC/DC converter circuit to which the smoothed output of the smoothing section (2) generated between the connection points P and N is supplied, and supplies driving DC to the inverter drive circuit and the active filter control circuit, which will be described later. e34) is an active filter type control circuit for controlling the drive of transistor (2), which consists of a digital control circuit driven by the power supply from the converter circuit shaft, and which controls the voltage detection signal between the detectors and the internally set smoothing voltage. Supplying a high frequency switching drive signal whose on period or frequency changes depending on the difference from the voltage control reference signal to the base of the transistor (G),
Based on the comparison between the current detection signal of the detector +3151 and an internally set overload reference signal, the ON period or frequency of the switching drive signal is limited to a range in which the transistor (c) does not become overloaded.

The part is an inverter drive circuit installed in place of the drive IE/I@J path (to) in Figure 2, and the transistor (to), α
→.

Together with the transformer Qf9 and the detector (A), it forms a feedback control type high frequency conversion section 01, which is driven by the power supplied from the converter circuit (A) and operates in the same way as the drive circuit (-) to convert the transistors (2), ( A drive signal is output to 141. 32 is an output rectifying and smoothing section formed by diodes αη, # and reactor α, and converting section c3υ
The high-frequency alternating current is rectified and smoothed, and a constant current controlled direct current is supplied to the workpiece and the arc load of the torch electrode.

Then, the 10 input to input terminals (1) and (2)
The power AC of 0 V or 200 V is rectified by a rectifier (E), and at this time, a rectified output proportional to the power AC, that is, the input AC, is generated between the output terminals 1) and (-).

In addition, due to the drive signal of the control circuit, the transistor (to) performs high frequency switching at a frequency sufficiently higher than the power supply AC, and during the on period of transistor four, the reactor IV
A current with rectified pressure flows through the transistor handle via @, and energy with the polarity in the direction of the arrow shown in the figure is accumulated in the reactor IV@. During the off period of the transistor handle, the reactor I- At this time, due to the high voltage obtained by superimposing the voltage of the reactor (5) on the voltage of the rectified output, a voltage of opposite polarity is generated at the input AC during periods other than the positive and negative peak values of the input AC, such as zero cross voltage. Even in the period near the capacitor 1371, f3
81 is charged.

So, capacitor +371, +38! The rectified output is smoothed by the converter section 3η from the capacitor section (7).
The smoothed output is supplied to the converter circuit (39).

By the way, the voltage across the capacitor +371, 1381.

That is, the smoothed voltage between the connection points P and N is detected by the detector (33), and a voltage detection signal proportional to the smoothed voltage is output from the detector (Zheng) to the control circuit (2).

The control circuit (34) digitally amplifies the error of the detection signal of the detector (33) and the constant voltage control reference signal of the smoothed voltage, and performs pulse width modulation or frequency modulation so that the detection signal matches the reference signal. The on-period or frequency of the drive signal to the transistors (to) is variably controlled, and the voltage of the smoothed output is feedback-controlled to a constant voltage that does not damage the transistors α3, Q4), etc.

Therefore, regardless of whether the input AC is a power supply AC of 100 V or 200 V, the reactor lv@, the transistor 2, and the control circuit 1341 input the smoothed voltage to the capacitor section (7) so that it becomes a constant voltage. The rectified output is filter-limited and is transferred from the filter section (7) to the conversion section 6.
The smoothed output output to υ, that is, the voltage of the DC output, is held at a constant voltage.

In order to prevent damage to the transistor (to) due to overcurrent, the control circuit □□□ receives the detection signal of detector +3 (1) and the detection signal of detector (351), In other words, based on the digital comparison of the detection signal proportional to the rectified output current and the overload reference signal,
Variation of the on period or frequency of the drive signal for the transistor (to) is limited so that the current flowing through the transistor (to) does not exceed the current value of the reference signal.

Then, due to the operation of the converting section 0η and the rectifying and smoothing section +32,
Constant current controlled direct current is supplied to the arc load, and at this time, regardless of whether the input AC voltage is 100 V or 200 V, damage to the converting section 0υ, rectifying and smoothing section L (Z, etc.) will not occur.

Also, based on the high frequency switching of the transistor (c) and the release of the stored energy of A/@, the capacitors +371 and +aai are repeatedly charged even in areas other than the vicinity of the positive and negative peak values of the input AC, and the input AC is This improves the efficiency of input AC utilization and improves the power factor of the arc equipment.

1. Based on high-frequency switching of transistors, the input AC through the rectifier always flows through the device, preventing waveform distortion of the input AC and adversely affecting other equipment.

In the above embodiment, the input AC is 100V and 20V.
Although we have described the case where either 0 V power AC is input, the input AC may be one of two types of AC different from the examples, for example, 200v and 400v AC, or three or more types of AC. It goes without saying that this method can be applied to cases where .

Further, in the above embodiment, the direct current supplied to the arc load is controlled at a constant current, but a voltage detector may be provided in place of the detector (a), and constant voltage control may be performed.

Further, the configuration of each part is not limited to the embodiment, and for example, a semiconductor switching element other than a switching transistor may be used as the semiconductor switching element.

Of course, the present invention can be applied to DC power supply devices for various arc devices such as arc welders, arc cutting machines, and arc lamp devices.

〔Effect of the invention〕

As described above, according to the arc power supply device of the present invention, by controlling the high frequency switching of the semiconductor switching element, the smoothing voltage of the smoothing capacitor section is controlled at a constant voltage regardless of the input AC voltage, and the smoothing voltage is controlled according to the input AC voltage. It is possible to improve operability by eliminating switching operations, and to charge the smoothing capacitor part during the entire period of input AC using the stored energy of the reactor, improving the utilization efficiency of input AC and reducing the arc including the device. It is possible to improve the power factor of the device, and also prevent waveform distortion of input AC to prevent adverse effects on other devices.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of one embodiment of the arc power supply device of the present invention, and FIG. 2 is a block diagram of a conventional arc power supply device. Kan... Rectifier, (Foundation)... React/L/, ■...
・Switching transistor, wire... diode for backflow prevention, ■... smoothing capacitor section, @υ... high frequency conversion section 1 country... output rectification smoothing section, l33)... voltage detector, 1341 ...Active fill control circuit.

Claims (1)

[Claims] (1) An input rectifier that rectifies input AC and converts it into DC; a reactor and a semiconductor switching element provided in series between the DC output terminals of the input rectifier; and a connection point between the reactor and the switching element. a smoothing capacitor section into which the voltage is injected via a diode for backflow prevention; a high-frequency converter section that converts the smoothed output of the smoothing capacitor section into high-frequency alternating current; and a high-frequency converting section that rectifies and smoothes the high-frequency alternating current and supplies it to the arc load. a voltage detector that detects the smoothed voltage of the capacitor section; and a voltage detector that supplies a drive signal for high-frequency switching to the switching element based on the detection signal of the detector and a reference signal, and detects the smoothed voltage of the capacitor section; An arc power supply device comprising: a control section for controlling a constant voltage;