JPH047671Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a power supply device used for welding, cutting, etc.

[Conventional technology]

Conventionally, when cutting metal workpieces, cutting machines using acetylene gas were mainly used.
Recently, air plasma cutting machines have been widely used in place of acetylene gas cutting machines, as the so-called flashback phenomenon, in which gas burns inside the jet nozzle, frequently occurs and is somewhat unsafe. The reason for this is that it has a simple configuration because it consists of an air supply compressor, a DC power source, and a plasma generation nozzle, and that it does not require replenishment of acetylene gas and has excellent operability.

By the way, when manufacturing a certain type of structure using metal materials, the metal workpieces are cut into a predetermined shape using the above-mentioned cutting machine, and then appropriately combined and welded to manufacture the structure. In some cases, cutting and welding of metal workpieces may be carried out in parallel or as part of an assembly line.

[Problem that the invention attempts to solve]

However, in such a case, the output current-output voltage characteristics of the power supply device used for cutting and the output current-output voltage characteristic of the power supply device used for welding are shown by the solid line and the dashed-dotted line in Fig. 3, respectively. As shown in the figure, cutting requires low current and high voltage, and welding requires high current and low voltage, so conventionally two power supplies are required: one for the cutting machine and one for the welding machine. There are problems in that installation space must be secured and it is very expensive.

Therefore, the technical object of this invention is to provide a power supply device that can switch the output current-output voltage characteristics with a simple configuration and can be used for two different purposes such as cutting and welding.

[Means for solving problems]

This invention was made with the above points in mind, and includes a first diode whose anode is connected to one output terminal of an AC power supply, and a second diode whose cathode is connected to the one output terminal. , a third diode having a cathode connected to the cathode of the first diode, a fourth diode having an anode and a cathode connected to the anodes of the second and third diodes, respectively, and a fourth diode having both ends connected to the first diode.
a series circuit of two smoothing capacitors connected to the cathode of the diode and the anode of the fourth diode, and a series circuit of two inverter transistors connected in parallel to the series circuit;
first and second switches, both of which have one end connected to the other output terminal of the power supply and whose other ends are respectively connected to the anode of the third diode and the connection point of both the capacitors, and are turned on alternately;
a transformer in which both ends of a secondary winding are connected to a connection point between the transistors and a connection point between the capacitors, and a rectifier circuit in which two input terminals are connected to both ends of the secondary winding of the transformer, respectively; first to third output terminals respectively connected to both output terminals of the rectifier circuit and an intermediate tap of the secondary winding; and a first switch provided between the third output terminal and the intermediate tap and connected to the first switch. A third switch that turns on and off in conjunction with the second switch, and a fourth switch that is provided between the second output terminal and one output terminal of the rectifier circuit and turns on and off in conjunction with the second switch. It is a power supply device.

[Effect]

Therefore, according to this invention, the first and third switches are turned off, the second and fourth switches are turned on, and the connection point between both capacitors is connected to the AC power source instead of the connection point between the third and fourth diodes. is connected to the other output terminal of the transformer, and the first,
A voltage doubler rectifier circuit is formed by the second diode and both capacitors, and the output of the voltage doubler rectifier circuit is converted into alternating current by the inverter of both transistors, and then rectified by the rectifier circuit on the secondary side of the transformer.

On the other hand, when the first and third switches are turned on and the second and fourth switches are turned off, the first to
A fourth diode is bridge-connected to form a full-wave rectifier circuit in place of the voltage doubler rectifier circuit, and the output of this full-wave rectifier circuit is converted into alternating current by the inverter of both transistors, and the output is converted into alternating current by the rectifier circuit on the secondary side of the transformer. rectified.

At this time, by turning on and off each switch appropriately, a voltage doubler rectifier circuit is installed on the primary side of the transformer.
A full-wave rectifier circuit will be selectively formed,
It becomes possible to easily switch the output characteristics of the power supply device, and one power supply device can be used as a power supply device having two different types of output characteristics.

〔Example〕

Next, this invention will be explained in detail with reference to FIGS. 1 and 2 showing one embodiment thereof.

In FIG. 1, 1 and 2 are first and second terminals connected to the output terminal of an AC power source (not shown);
is a first diode whose anode is connected to the first terminal 1, 4 is a second diode whose cathode is connected to the first terminal 1, and 5 is a first diode whose cathode is connected to the first terminal 1.
A third diode 6 is connected to the cathode of the second diode 4 and the third diode 6 is an anode.
A fourth diode is connected to the anode of the diode 5, 7 is a series circuit of two smoothing capacitors 8 and 9 whose both ends are connected to the cathode of the first diode 3 and the anode of the fourth diode 6, and 10 is an NPN. It is a series circuit of two type inverter transistors 11 and 12, and the emitter of one transistor 11 and the other transistor 1 are connected in series.
The collectors of the transistor 11 and the emitter of the transistor 12, which are one end and the other end of the series circuit 10, respectively, are connected to the first
Cathode of diode 3 and fourth diode 6
are connected to the anodes of both transistors 1 and 1 by an inverter control circuit (not shown).
A base control signal is output to bases 1 and 12,
Both transistors 11, 12 are turned on and off alternately.

13 has one end connected to the second terminal 2 and the other end connected to the third terminal
The first switch 14 connected to the anode of the diode 5 has one end connected to the second terminal 2 and the other end connected to the connection point of both capacitors 8 and 9, and is turned off when the first switch 13 is turned on and off. A second switch 15 to be turned on is a transformer 1 whose both ends of the primary winding 15a are connected to the connection point between both transistors 11 and 12 and the connection point between both capacitors 8 and 9.
6 is four rectifier diodes 17a, 17b, 1
This is a rectifier circuit consisting of 7c and 17d, and both input terminals are connected to both ends of the secondary winding 15a of the transformer 15.

18 to 20 are the positive and negative output terminals of the rectifier circuit 16 and the first to third output terminals connected to the intermediate tap t of the secondary winding 15b; 21 is the first output terminal 1;
8 and the positive output terminal of the rectifier circuit 16; 22 is a smoothing reactor provided between the third output terminal 20 and the intermediate tap t and the first switch 13;
A third switch 23, which is turned on and off in conjunction with the second switch 14, is a fourth switch provided between the second output terminal 19 and the negative output terminal of the rectifier circuit 16, and is turned on and off in conjunction with the second switch 14. Turn off.

In addition, each switch 13, 14, 22, 23 is
Turned on by a switch control circuit (not shown)
It is assumed that OFF control is performed.

Then, when the first and third switches 13 and 22 are controlled to be in the off state and the second and fourth switches 14 and 23 are controlled to be in the on state by the switch control circuit, the equivalent circuit in this state is shown in FIG. As shown in a, the connection point between both capacitors 8 and 9 is connected to the second terminal 2 instead of the connection point between the third and fourth diodes 5 and 6, and the connection point between the first and second diodes 3 and 4 and both capacitors is connected to the second terminal 2. A voltage doubler rectifier circuit consisting of 8 and 9 series circuits 7 is formed, and the positive and negative half waves of alternating current to the first and second terminals 1 and 2 are rectified by the first and second diodes 3 and 4, respectively. , both capacitors 8 and 9 due to the rectified output from both diodes 3 and 4.
are charged, a DC voltage twice the AC voltage appears across the series circuit 7 of both capacitors 8 and 9, and both transistors 11 and 11 are turned on and off alternately at a predetermined frequency by the inverter control circuit.
12 converts the charging voltage of both capacitors 8 and 9 into AC again, and the primary winding 15a of the transformer 15
The alternating current voltage applied to the secondary winding 15b and appearing across the secondary winding 15b is again full-wave rectified by the rectifier circuit 16 to generate a direct current voltage between the first and second output terminals 18 and 19.

On the other hand, the switch control circuit controls the first and third switches.
When the switches 13 and 22 are turned on and the second and fourth switches 14 and 23 are turned off, the equivalent circuit in this state becomes as shown in FIG. 2b, and both capacitors 8 and 9 The connection point of the third and fourth diodes 5 and 6 is connected to the second terminal 2 instead of the connection point of AC to 1 and 2 is full-wave rectified by a full-wave rectifier circuit constituted by diodes 3 to 6 and smoothed by both capacitors 8 and 9, and the DC output of the rectifier circuit is alternately turned on and off. 11 and 12, it is converted into alternating current again and applied to the primary winding 15a of the transformer 15, and the secondary winding 15
The voltage that appears alternately between one end of b and the intermediate tap t and between the other end and the intermediate tap t is half-wave rectified by the two diodes 17a and 17b, respectively, and is output to the first and third output terminals 18, A DC voltage is generated between 20 and 20 seconds.

At this time, as can be seen by comparing both the equivalent circuits in FIGS. 2a and 2b, the first and third switches 13, 22
is on and the second and fourth switches 14 and 23 are off, that is, in the case of b in the figure, the first and third switches 13 and 22 are turned off, and the second and fourth switches 14 and 23 is on, that is, the voltage is 1/2 on the primary side of the transformer 15 and 1/2 on the secondary side compared to the case in a of the same figure, and as a result, the output voltage in the circuit of the circuit in b of the same figure becomes 1/2. is 1/4 of a in the same figure,
Moreover, in the circuit shown in FIG. 2B, the rectified current value is higher than that in the case shown in FIG. The final output current is b in the same figure.
Therefore, the circuit configuration shown in figure a is used as a disconnection power supply device that requires low current and high voltage output characteristics, and the circuit configuration shown in figure b is used for high current and high voltage output characteristics.
It can be used as a welding power supply device that requires low voltage output characteristics.

[Effect of idea]

As mentioned above, according to the power supply device of this invention,
By simply selectively turning on or off each switch as appropriate, the output current-output voltage characteristics can be switched between two types, allowing one power supply unit to be used for two different purposes, such as cutting and welding. This makes it possible to provide a power supply device that does not take up much installation space, has a simple configuration, and has excellent functionality.

[Brief explanation of the drawing]

Figure 1 is a wiring diagram of one embodiment of the power supply device of this invention, Figures 2a and b are wiring diagrams in different states of Figure 1, and Figure 3 is the output of a general power supply unit for cutting and welding. It is a characteristic diagram. 3 to 6...first to fourth diodes, 7, 10...
...Series circuit, 13, 14...First and second switch, 15...Transformer, 15a, 15b...1
Next, secondary winding, t... intermediate tap, 16... rectifier circuit, 18-20... first to third output terminals, 2
2, 23...3rd and 4th switches.

Claims (1)

[Scope of utility model registration request] a first diode whose anode is connected to one output terminal of the AC power supply; a second diode whose cathode is connected to the one output terminal; and a third diode whose cathode is connected to the cathode of the first diode. , the anode and the cathode are the second
and a fourth diode connected to the anode of the third diode, and a series circuit of two smoothing capacitors each having both ends connected to the cathode of the first diode and the anode of the fourth diode; A series circuit of two inverter transistors connected in parallel, one end of which is both connected to the other output terminal of the power source, and the other end of which is connected to the anode of the third diode and the connection point between the two capacitors. a first and second switch that is turned on alternately; a transformer having both ends of a primary winding connected to a connection point between the two transistors and a connection point between the two capacitors;
a rectifier circuit having two input terminals respectively connected to both ends of the secondary winding of the transformer; and first to third input terminals respectively connected to both output terminals of the rectifier circuit and intermediate taps of the secondary winding. output terminal and
a third switch provided between the third output terminal and the intermediate tap and turned on and off in conjunction with the first switch; and between the second output terminal and one output terminal of the rectifier circuit. and a fourth switch that is provided and turns on and off in conjunction with the second switch.