SU1547987A1 - Single-phase welding rectifier - Google Patents

Abstract

The invention relates to electrical engineering, in particular to single-phase welding rectifiers and can be used in portable welding devices. The purpose of the invention is to improve the consumer properties of the device by expanding the range and smoothness of welding current control, as well as expanding the functionality of the rectifier by performing starter motor starting modes and charging the batteries. The rectifier contains a transformer with a secondary winding of three parts located on the two rods of the magnetic circuit, one of the parts being farthest from the zone of the primary winding. Two rectifier diodes and four thyristors, which are connected to each other, with transformer leads and with an output circuit, are provided to provide rectifier bridges, which operate the device in welding, charge, start-up modes. The thyristor control unit has four outputs connected to the thyristor control circuits. 2 hp f-ly, 6 ill., 1 tab.

Description

The invention relates to electrical engineering and can be used in portable welding rectifiers for manual arc welding with fusion electrodes with single-phase voltage supply, for example, in household conditions.

The aim of the invention is to enhance the functionality and improve consumer properties by increasing the range and smoothly adjusting the current of the rectifier.

FIG. 1 shows a basic single phase electrical circuit.

welding rectifier; in fig. 2 - transformer structures; in fig. 3- functional scheme of the control unit. neither; in fig. 4 is a power supply circuit of the control unit; in FIG. 5 — graphs of external characteristics of a single-phase welding rectifier; in fig. 6 - diagrams of rectifier voltages.

The welding rectifier (FIG.) Contains a transformer with primary winding 2 and secondary winding 3, a smoothing reactor 4, two diodes 5 and 6, while the anode of diode 5 and the cathode of diode 6 are connected to end 7 of the secondary

H SO 00

3154

Choi winding. The secondary winding of the transformer consists of three parts 8-10, with the beginning of the first part 8, the second 9 and the third 10 parts are connected together. The beginning of the second part is the output 11 of the larger voltage, the beginning of the third part is the output 12 of the lower voltage, and the end of the first part is the end 7 of the secondary winding. Four thyristors 13–16 were inserted into the rectifier, with the anode (thyristor 13 and thyristor cathode 14 co ™ dinene, with output 11 of a higher transformer voltage, thyristor anode

15 and the cathode of the thyristor 16 — with the output 12 of a lower voltage; the cathodes of the thyri-, stor 13 and 15 and diode 5 are connected together and connected to the output of the smoothing rector 4, the second output of which is the positive conclusion

17 rectifier, thyristor anodes 14 and

16 and diode 6 form a negative output 18 rectifier. A control unit 19 is also inserted in the rectifier, the synchronization circuit 20 of which is connected to the terminals 11 and 7 of the secondary winding. The first output 21 is connected to the thyristor control circuits 13 and 14,

and the second output 22 is connected to the thyristor control circuits 15 and 16. The additional winding 23 of the transformer is connected to the power supply circuit of the thyristor control unit 19.

On one of the rods of the magnetic conductor 24 (Fig. 2) are located the network winding 2, the first 8 and the second 9 parts of the secondary winding and the additional winding 23. The third part 10 is the most distant from the location zone of the network winding 2 and has the largest reactance - the three parts of the secondary winding on the two rods of the magnetic circuit, provides the first 8 and second 9 reactors of the windings, necessary for obtaining a higher welding current and a smaller steepness of the external characteristic at the higher voltage terminal P, and howling 8 and third 10 parts required to produce smaller and more welding current slope characteristic at the outer terminal 12 less voltage.

The thyristor control unit (Fig. 3 contains a potentiometer 25 of the current regulator, a sawtooth voltage generator 26, a null organ 27, a comparator 28, four elements AND 29-32, two elec-

Q

Q

five

five ,

0

0

five

ment OR 33 and 34, two blocking generators 35 and 36 and switch 37 of the modes Welding, Zar d, Start. The outputs of the first blocking generator 35 are the first outputs 21 of the control unit and are connected to the control circuits of the thyristors 13 and 14, and the outputs of the second blocking generator 36, which are the second outputs 22 of the block, are connected to the control circuits of the thyristors 15 and 16. The input the first blocking generator 35 is connected to the output of the first element OR 33, the first input of which is connected to the output of the first element AND 29. The second input of the first element OR 33 is connected to the output of the second element And 30. The input of the second blocking generator 36 is connected to the output of the second element and OR 34. The first input of the second element OR 34 is connected to the output of the third element AND 31, the second input of the second element OR 34 is connected to the output of the fourth element AND 32. The input of the zero-body 27 is the synchronization circuit 20 and through diodes 38 and 39 is connected to terminals 11 and 7 of the secondary winding, and its output is connected to the input of the sawtooth generator 26 and the first input of the third element 31. The output of the generator 26 is connected to a non-inverting input of a comparator 28, the inverting input of which is connected to a movable contact of the potentiometer 25 of the current regulator but. The output of the comparator 28 is connected to the first inputs of the first 29, second 30 and fourth 32 elements I. The second inputs of the first 29 and third 31 elements And connected to the output Welding of the mode switch 37, the second input of the fourth element And 32 connected to the output Zar d of the mode switch 37, the second input of the second element And 30 - with the output Start switch 37.

The control unit (Fig. 4) is powered from an additional winding 23, the middle terminal of which is a neutral wire, and the extreme terminals are connected to the terminals of a rectifying bridge 40. The circuit provides the two-pole constant voltage required for the comparator.

In the Welding mode (Fig. 3), a single signal from the mode switch 37 is fed only to the input of the element AND 29 and 31. At the same time, the blocking generator 36 through the element OR 34 and the element

And 31 is connected to the output of the null organ 27, the blocking generator 35 through the element OR 33 and the element AND 29 connected-j is not connected to the output of the comparator 28. The latter and the generator 26 of the saw-tooth voltage form a phase-shifting device that provides control of the thyristors with a delay of phase depending on the position of the potentiometer motor 25.

At the moments of time when the voltage on the secondary winding 3 of the transformer crosses a zero value, a pulse appears at the output of the null organ 27, which through the elements 31 and 34 enters the input of the block generator 36. One of the thyristors 15 or 16. At terminals 17 and 18 of the rectifier, a lower voltage appears as the rectifier bridge is connected to the terminals of the first and third parts.

The sequence of signals to the elements And is given in the table.

The signal at the output of the comparator 28 appears with a delay set by potentiometer 25, and through elements 29 and 33 goes to the blocking generator 35. The signal from the latter opens the thyristor 13, while the voltage on the load increases in a jump (up to a higher voltage). as a rectifying bridge connected to the first and second parts, and the previously opened thyristor 15 is locked. This is how the welding current is regulated. The current control range is limited by the external characteristic 41 (Fig. 5) at the higher voltage terminal and the characteristic 42 at the lower voltage terminal. The largest 12 and the smallest 14 welding currents are determined by the intersection of the external characteristics with the characteristic of the arc 43. By changing the position of the slider of the potentiometer 25, i.e. by changing the opening delay angle of the thyristors 13 and 14, you can get any

0

0

from current values in the range from I to 1, providing smooth control of the welding current and voltage, the form of which and the control pulses at the outputs of the blocking generators 35 and 36 are shown in FIG. 6 (curve 44). Curve 45 represents the network voltage. In the charge mode, a single signal from the switch 37 of the modes (Fig. 3) is fed only to the input of the element 32, providing the connection of the second blocking generator 36 through the elements 34 and 32 with the output of the comparator 28. V

In this mode, the thyristors 15 and 16 are controlled with a phase delay, i providing smooth current control for -. range from values close to zero (characteristic 46 on (fig. 5), to values limited by characteristic 42, which provides various possibilities from charging to forced charging of batteries. Direct 47 (fig. 5) shows the greatest voltage -

5 charge a 12 volt battery.

In the Start mode, a single signal from the mode switch 37 (Fig. 3) is fed to the element 30, connecting the blocking generator 35 through the element 33 to the Phase-shifting device, i.e. comparator output 28. The current control range in this mode is from 0 to values limited by characteristic 41 (Fig. 5), which allows for starter start of the car engine during the cold season with parallel connection of the rectifier to the car battery. Such a start reduces the battery current, increasing its service life. Direct 48 (Fig. 5) shows the lowest voltage during the starter start e car.

Compared to the known, the proposed single-phase welding rectifier provides smooth current control in three ranges, which improves consumer properties of the rectifier.

Q and extends the functionality due to the use of a rectifier for charging batteries and starting a car engine.

For household welding rectifier, the highest welding current reaches I25 A, and the minimum 50-60 A. With these parameters, the rectifier developed by the proposed solution can provide a charge of 12 volts,

0

five

0

five

batteries with a current from 2 to 70-90 A, providing a nominal or forced charge of batteries with a capacity of 42-100 Ah. In the same mode, it is possible to ensure the start-up start of a passenger car with parallel switching on batteries and welding rectifier, while the rectifier current reaches 80-100 A. In the Start position, the welding rectifier provides starting current up to 200-220 A, which allows for in parallel with the operation of the battery rectifier and the accumulator, ensure the starter start-up of the load- btix cars during the cold season. Such an application of a welding rectifier can be useful in everyday conditions, in collective garages, gardens, agricultural and small workshops.

The design of the welding rectifier does not have mechanical switches in the power circuit, switching these circuits in various x modes is performed by thyristors, which increases the rectifier life, the transformer has a smaller terminal, which reduces the laboriousness of manufacturing and assembly. The use of integrated electronics allows the use of modern manufacturing technology based on a printed circuit.

F

formula of invention

Claims (3)

1. A single-phase welding rectifier, a transformer, whose secondary winding consists of parts with a different number of turns, located on two rods of the magnetic conductor, a smoothing reactor and two diodes, the anode of the first of which and the cathode of the second are connected to the end of the secondary winding, differing - so that, in order to expand the functionality and improve consumer properties by increasing the range and smooth current control, it is equipped with four thyristors and a thyristor control unit, and toric winding of the transformer is made of three parts, the top ends of the first and second and third portions are joined together, the beginning of the second portion of the winding is larger terminal voltage, a third top part is smaller output voltage, the first end portion 0 five 0 five 0 five 0 five is the end of the secondary winding, the third part of the winding is located with the greatest distance from the primary winding area, while the anode of the first and second thyristor cathodes are connected to the output voltage of the transformer, the third and fourth cathode are connected to the output voltage of the transformer, cathodes the first, third thyristors and the first diode are connected together and connected to the view of a smoothing reactor, the second output of which is the positive output of the rectifier, the anodes of the second and fourth iristorov and second diodes are connected together and form the negative output of the rectifier, the first two output thyristors control unit connected to the chains controlling the first and second thyristors, two second output - with the chains controlling the third and fourth thyristors. 2. The rectifier according to claim 1, of which is that the thyristor control unit is made in the form of a potentiometer for a current regulator, a saw-tooth voltage generator, a zero-organ, a comparator, four AND elements, two OR elements , two blocking generators, mode switch Welding, Charging, Start, with two outputs of the first blocking generator — the first outputs of the control unit and two outputs of the second blocking generator — the second outputs of the control unit; the input of the first blocking generator is connected to the output of the first the element OR, the first input of the first the OR element is connected to the output of the first element AND, the second input of the first element OR is connected to the output of the second element AND, the input of the second block generator is connected to the output of the second element OR, the first input of the second element OR is connected to the output of the third element AND, the second input of the second element OR is connected to the output of the fourth element AND, the input of the zero-organ is connected to the terminals of the secondary winding of the transformer, the output of the zero-organ is connected to the input of the sawtooth generator and the first input of the third element AND, the output of the generator ora sawtooth voltage is coupled to the non-inverting input of the comparator, the inverting input of the comparator is connected to podvizh9 the contact of the potentiometer of the current regulator, the comparator output is connected to the first inputs of the first, second and fourth elements AND, the second input of the first element AND and the second input of the third element And connected to the output of the welding mode switch, the second input of the fourth element AND connected to the output ZAR d mode switches, the second input of the second element And is connected to the output of the Start mode switch. 547987 U 3. Rectifier according to claim 1, characterized in that, in order to improve technical and economic performance, the transformer is provided with an additional winding with an average output, which is connected to the control power supply neutral wire, thyristors, and the winding leads are connected to the rectifier supply bridge thyristor control. .five ten i $ ig1 ft 10 fb-ii -GY-27, / 1 P-III-i Fig.Z + U FIG. 2 Fy w