JPS6178565A - Dc arc welding power source device - Google Patents

Abstract

PURPOSE:To disuse the provision of the third coil on high frequency transformer and to reduce a power consumption by constituting so as to control the magnetic deviation of a high frequency transformer only by the controlling circuit of a weak current. CONSTITUTION:A DC arc welding power source device drives a high frequency transformer 7 with conducting alternately a pair of switching elements 9, 10 and controls the output current and voltage feeding to a load. Besides the converting means 11 converting the current flowing at the conductive time of the switching element into a voltage signal, a pair of sample and hold circuits 12, 13 storing with taking out the current value flowing in the switching element from the converting means 11, the pulse width regulating circuit 15 outputting the pulse signal of two phases parts regulating the conductive time of the switching element and the logical circuit 16 outputting an actuation signal to the sample and hold circuits 12, 13 simultaneously with the conductive time together with conducting alternately a pair of switching elements with outputting alternately said pulse signal on each phase are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement of a DC arc welding electric DG device, and in particular controls the conduction time of a pair of switching elements by pulse width control to reduce the amount of electricity generated in a high frequency transformer. This is designed to suppress biased magnetism.

Conventional technology Direct current arc welding in which a pair of switches/elements are alternately turned on to drive a high frequency transformer 2 to feedback control the output current and output voltage supplied to the load.
In this device, the biased magnetization of the wave pressure device is suppressed; 1.II! This is already known.

That is, in this case, a tertiary layer is newly added to the core of the high frequency transformer, and a two-stone switching transistor is connected to the primary winding of the high frequency transformer or the secondary winding of the high frequency transformer. The current difference between the currents flowing through the two rectifiers is detected, and the tertiary winding is driven by this current difference, and the DC magnetic flux generated by the biased magnetization is reduced by the direct tA i≦1 flux of the tertiary winding. There is this thing that is configured to cancel it out.

In general, such grooves, 9, are used in high frequency transformers:
Since there are four ways to pass current through the tertiary wire installed in 1A, it is inevitable that the equipment will be larger in actual production and require a large amount of control power for ILD when in use. First, especially in this case, power consumption is a problem that cannot be ignored since the input current lk during welding is controlled.

Problems that the invention attempts to solve 190. In view of the 11 feelings of "L, Ei" C1iil) Evening sun 1. The problem to be solved is to make the device smaller and lighter, significantly reduce power consumption, and provide more accurate control.
Each device is provided.

Means for Solving the Problems According to the present invention, the above problems are solved by providing a DC arc welding electric S device having the following configuration.

In other words, this device uses a DC arc that alternately conducts a pair of switching elements, drives several transformers to supply the output to the load, and feedback-controls the output voltage. This is an improvement of a welding power supply device, which particularly includes (a) a voltage converting means for converting the current T4fL flowing when each of the above-mentioned phantom switching elements is turned on into a voltage signal, and (b) each of the above-mentioned switch knob elements. (c) a pair of pull-hold circuits which are opened and activated when conduction and extracts and stores the current value flowing through each of the switch knob elements from the voltage/voltage converting means; 7
A pulse width control circuit that outputs a two-phase pulse No. 18 that defines the conduction time of f and E- from the output from the pull-hold circuit (in order to eliminate the error No. 9, the above-mentioned switching); d) This pulse [No. 9 of the Niwa Oki output from the II control circuit is output alternately to each phase silver, and the above-mentioned moon switching element is alternately passed through f#, and this ∆! When conductive, connect the logic circuit that outputs the 1 signal to the above pair of sample hold circuits in synchronization.
Here is a summary of what happened.

Device.

Invention glue 1 result, l: 141 of invention? ? According to the above, the configuration is such that the biased magnetization of the transformer is controlled only by a weak current control circuit, so there is no inconvenience like installing a tertiary winding in the high frequency transformer as in the conventional example. Moreover, it has the advantage of significantly reducing power consumption.

Furthermore, since the weak current control circuit is configured separately from the high frequency circuit section that alternately turns on the switch knob elements, insulation processing can be performed simply by PJI.

Furthermore, since the configuration uses a pair of sample and hold circuits to extract the current flowing through the switching element, the control operation speed is faster than the conventional method that detects the average value, and it is possible to perform control with a higher degree of T# in a faster manner. .

In addition, since a common current flowing through each switching element is taken out from the current/voltage conversion means and detected via a pair of sample and hold circuits, isolation is also achieved.
! It becomes an i+ car, and Nostem as a whole can obtain a welding power supply device with less control error.

EMBODIMENTS AND OPERATIONS OF THE INVENTION A preferred embodiment of the apparatus of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the overall configuration corresponding to the claims, and FIG. 2 is a diagram showing the block diagram shown in FIG. 1 in more detail.

Referring to FIG. 1, l is a consumable electrode, 2 is a welding arc generated during welding, 3 is a base material that becomes a welded member,
4 is a voltage detecting voltage supplied to the load.
4 voltage detection 2”r-5 used during illumination
゛Yu ("III+! Two upstream? Constant current control for detection 0:22 Sagawa 4. This 7A detector, 6:!
Rectifier iAI created using rectifier l1! ! Circuit 8: Shows a smoothing circuit using a subcontracted coil.

-[T-7! :I Sushu $l transformer, 9. 105 and tII capture each other, - the power transformer of the lamp/sufuna] is a switching element constructed by concubining, I9 is a direct current for driving the switch element 9.10.
~, 11 is the current output from the I port by converting the current Ay'L into a voltage signal when +1 of the switching A core '1.10 is passed.
'Heart voltage 1Q means, 12.13 is a switching element 9.
A pair of sample and hold circuits that are activated when 10 is turned on, 14 is a sample and hold circuit +2°1.3
output (an error amplifier that amplifies the error of No. 3, 15 is a pulse convergence I11 circuit that outputs a two-phase power pulse signal with a width corresponding to the output signal of the error amplifier 14, and 16 is a pulse width I11 circuit) The pulse signals for two phases outputted from 15 are alternately output to each phase silver to operate the sample hold circuit 1213 and the driver circuit 17 (logic circuit that alternately outputs No. 3, :8:; switching element 9 .10 is a drive train driven by a driver circuit 17 to alternately switch the motors.

As shown in the figure, the device of the present invention uses a method of driving an inverter circuit, which is a combination of a pair of switching elements 9 and 10 and a high frequency transformer 7, by pulse width control.

Here, sample and hold circuits 12 and 13 are logic circuits 1
Operation sent from No. 6 (alternately activated by No. 2,
Switching element 9. In synchronization with the IO JJ111 time, current is taken out from the current/voltage pressure loss means 11 and stored.

In the error amplifier 14, the sample hold circuit 12
The error in the outputs of and 13 is amplified, and this amplified error signal is input to the pulse width control circuit 15 at the subsequent stage.

The pulse width control circuit 15 outputs a two-phase pulse signal having a width corresponding to the manually input error signal.

2]°, ゛renu (1-No. 7 =, 4-Inventive device 2, 　) ゛1 It is opposite to the output signal of the circuit 1213' = 161 engagement pulse size or 1 For example, in a case where the output level is higher than 12 and 13, the output signal of 12 and the side where the wick is centered are small ξ.
It is specified to be a pulse of radiation.

Also, when the output level of 12.13 is the same size, 1,)
, a pulse signal of the same width is output for the own line.

When the above-mentioned two pulse signals output from the pulse width control circuit 15 are sent to the next logic circuit 16, the sent pulse signals are divided into two alternate cycles for each purpose. are output to sample and hold circuits 12 and 13 respectively.
and the driver circuit 17.

The result of this is that both switching elements9. τCa that makes 10! When a difference S occurs in the values, the conduction time of the switching element through which the larger current flows is shorter. 1
11 (on the other hand, the energization time becomes longer), and it is controlled so that there is no error in the current value passing through both switching elements, and the generation of biased magnetism in the core of the high frequency transformer 2 is suppressed. be done.

Next, referring to FIG. 2, the configuration of the apparatus of the present invention will be explained in more detail.

FIG. 2 is a diagram illustrating the block diagram of FIG. 1 in more detail.

To explain the components shown in detail in this figure,
The error amplifier 14 is a pair of amplifiers 141 having the same characteristics.
．． It is composed of 142, each with an increase of 1! The output signals from the sample and hold circuits 12 and 13 are inputted to the inputs of the L units 141 and 142 in an inverse relationship to each other.

The pulse width control circuit 15 is constructed by combining a pair of comparators 151 and 152 with the same characteristics and a triangular wave generator +53.
2, the triangular wave signal output from the triangular wave generating circuit 153 is set to 71, and this standard signal is used for each error term 1tai unit 1.
Error signal from 41.142 and another control signal generation circuit 2
The summed addition of control signals generated from 0′J! It is compared with the L signal.

In this second pulse width control circuit 15, as shown in FIGS. 3 and 4, the erroneous pulse width increase h141
．． 1.42 or ζ As the output error signal level increases, the output pulse (pulse axis of No. 3) becomes smaller, and conversely, the error signal level output from these error amplifiers 141 and 142 becomes smaller. The pulse axis of the output pulse signal becomes larger as the time increases.

The pulse signal output from the pulse width control circuit 15 is sent to the logic circuit 16 at the subsequent stage.

This logic circuit 16 is constructed using a D flip-flop 162, passes the output pulses of the comparators 151 and 152 through a NOR gate +61 to form a clock pulse, and also converts the Q, Human power A
A human input signal is input to one of the ND gates 163 and 164, and a pulse signal outputted from the Konopare 151 and 152 is input to each of the ND gates 163 and 164 as the other input signal.

Further, this D flip-flop 7 block 204 returns the output to the D human input signal JIi.

The pulse signals alternately generated from these two AND gates 163 and 164 are input to the sample and hold circuits 12 and 13 described above as actuation signals, and are also input to the driver circuit 17 as drive signals. ing.

Note that a driver transformer 18 is provided at the output end of the driver circuit 17, and the driver transformer 18 drives the pair of switching elements 9 and 10 described above.

Next, the operation of the circuit will be explained using FIGS. 3 and 4.

If the core of the high frequency transformer 2=7 does not have biased magnetism, the switching element 9. The currents flowing through IO are equal.

Therefore, the outputs of the sample and hold circuits i2.13 are at the same level, and the outputs of the error amplifiers 141 and 142 are both at the zero level.

Therefore, since the pulse axes of the pulse signals output from the comparators 151 and 152 are the same, the output pulses alternately output from the AND gates 163 and 164 also have the same width, and are sent to the sample and hold circuit 12 as actuation signals.
．． 13 and at the same time, it is also sent to the driver circuit 17 to each switching element 9. ] Have them repeat O in 4 turns.

As a result, the conduction times of the switching elements 9 and 10 become the same, the current flowing through each becomes zero, and the occurrence of biased magnetism in the core of the high frequency transformer 7 is effectively prevented.

The requirements for each part of (a) to (h) in the above cases/
The Guchat is shown in Figure 3.

Next, if biased magnetization occurs in the core of the high-frequency transformer 2S1, and especially considering the case where the current flowing through the switching element 9 becomes larger than the current flowing through the switching element 0, the output of the sample and hold circuit 12 is thicker than the output of the sample and hold circuit 13 (becomes), the output level of the error amplification 2i 141 is positive, and the error amplification n I
The output level of 42 becomes negative (in this case, both outputs are in an inverse relationship to each other).

As a result, the pulse width of the signal output from comparator 151 becomes smaller than the pulse width of the signal output from comparator 152. And these pulses are NO
Sent to R gate 161 and D flip-flop 162
clock pulses are formed, AND game) 163.1
From 64; the operation signal and drive (No. 3) are sent alternately to the sample hold circuits 12 and 13 and the driver circuit 17.

As a result, the switching element 9 is driven by a pulse with a small width, and its conduction time is reduced by the J of the switching element lO.
Since the q conduction time is also controlled to be short, the current flowing through the switching element 9 is reduced, the currents passing through both switching elements 9 and 10 are equalized, and biased magnetism is suppressed v1.

FIG. 4 shows a timing chart showing the operations of each part (a) to (h) in the above case.

It goes without saying that when the current value flowing through the switching element 9 becomes smaller than the current passing through the switching element 10, the operation opposite to the above-described operation is performed, and the biased Git is suppressed.

It goes without saying that the apparatus of the present invention can be modified in various ways other than the above-mentioned example of thick b'.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram of the device of the present invention, Fig. 2 is a block diagram showing mW shown in Fig. m1 in more detail, and Fig. 3
Both Figures 4 and 4 are from (a) to (hl) shown in Figure 2.
5 is a timing chart showing the operation of each part. (Explanation of symbols) In the figure 8, 7 is a high frequency transformer, 9.10 is a switching element, 11 is a current/voltage conversion means, 12.13 is a sample and hold circuit, 14 is an error amplifier, and 15 is a pulse width control The circuit 16 is a logic circuit.

Claims (1)

[Scope of Claims] A DC arc welding power supply device configured to control output current and output voltage supplied to a load by driving a high-frequency transformer by alternately conducting a pair of switching elements, comprising: (a) the pair of switching elements described above; (b) current/voltage converting means for converting the current flowing when each of the switching elements is conductive into a voltage signal; (c) a pair of sample-and-hold circuits that are extracted from the current/voltage conversion means and stored; (d) a pulse width control circuit that outputs pulse signals for each phase, and (d) alternately outputs pulse signals for two phases output from this pulse width control circuit for each phase to alternately switch the pair of switching elements. A DC arc welding power supply device comprising: a logic circuit that outputs an operating signal to the pair of sample and hold circuits in synchronization with the conduction of these circuits.