KR100225593B1 - Resistance welding control device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a resistance welding control device for performing welding by precisely detecting a welding current, comparing it with a set current, and performing a load correction according to the result. A keyboard for inputting set values, such as a display panel and welding conditions, an LED display unit for indicating the operating state of the system, a rectifier circuit unit for changing three-phase AC power to a DC power source, and the magnitude of the current output from the rectifier circuit unit. A bridge circuit portion consisting of four transistors so as to be supplied to a welding transformer by adjusting the voltage, a driving circuit portion controlling the operation of each transistor of the bridge circuit portion, a control circuit portion controlling the operation of the entire system according to the welding condition, and It is mounted on the output terminal of the rectifier circuit part to connect the bridge circuit part and the welding transformer. Hall current sensor for detecting the amount of current supplied to the welding electrode through the control circuit, and the operation of the driving circuit unit in accordance with the output signal of the control circuit unit, but the comparison of the welding current measurement value and the set value detected by the Hall current sensor It characterized in that it comprises a pulse width modulation circuit unit for performing various operations to control the operation of the drive circuit unit according to the result.

Description

Resistance welding control device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding control device which is sandwiched between gaps through two welded materials and is heated by electrical resistance to be bonded. In particular, the welding current is continuously detected and compared with the set current, and the load is corrected accordingly. The present invention relates to a resistance welding control apparatus for precisely performing welding.

1 to 3 are views showing the contents of a resistance welding control device (Korean Patent Publication No. 91-1005) according to the prior art, FIG. 1 is a block diagram showing a system configuration, and FIG. 2 is a front view showing a front panel. 3 is a diagram illustrating a menu screen displayed on the front panel.

Referring to FIG. 1, the conventional resistance welding control apparatus includes a liquid crystal display panel 12 for displaying an item on a screen so that welding conditions can be set, and the liquid crystal display panel for setting welding conditions by a user. (12) A keyboard 14 for selecting an item appearing on the screen and inputting a set value, and controlling various operations of each component and the device, and calculating various welding currents and calculating a comparison between the measured value and the set value. A CPU 32 which executes an operation, a control program, a display program, and a key input routine, which are provided to the CPU 32, and which store fixed character data in each screen to be displayed on the liquid crystal display panel 12; The ROM 34 and various calculation data obtained by the CPU 32 are temporarily stored, and the character data of the screen to be displayed on the liquid crystal display panel 12 and the keyboard 14 are stored. RAM 36 for storing the input schedule and setting values, a keyboard interface 38 for taking input data from the keyboard 14 and sending it to the CPU 32, and sending it out from the CPU 32. A CPU having a buffer memory for storing one screen of character data, the display controller 40 for displaying the character data on the liquid crystal display panel 12, and a schedule signal for initiating welding; An input / output interface 42 for determining a welding operation in accordance with a control signal from 32, and a welding transformer 56 for changing the input power source E to a voltage having a predetermined magnitude and supplying the welded materials 58A and 58B. And thyristors 54A and 54B mounted on the primary coil of the welding transformer 56 to determine supply of power, and to operate the thyristors 54A and 54B according to the output signal of the input / output interface 42. Thyristor A waveform restoring circuit 50 for receiving the welding current detected from the arcing circuit 48 and the annular coils 52 'and 52 wound around the input and output side conductors of the welding transformer 56, and restoring the waveform; The analog / digital conversion unit 44 which receives an analog welding current from the restoration circuit 50 and converts it into a digital signal and outputs it to the CPU 32, and the welding current detected from the annular coils 52 'and 52 And a timing circuit section 46 for detecting cycle timing, measuring energization time, and supplying operation timing signals for each component.

At this time, the CPU 32, the ROM 34, the RAM 36, the keyboard interface 38, the display control unit 40, the input / output interface 42, the analog / digital conversion unit 44, and the timing circuit unit ( 46 connects to the system bus 30, respectively.

Meanwhile, in the above configuration, the liquid crystal display panel 12 and the keyboard 14 are provided on the front panel 10 as shown in FIG.

In this case, the keyboard 14 includes a power key (power on and off) 16, a program key (program on and off) 18, a menu key (20), and a cursor key (cursor) 22a. 22d), up / on key 24a, down / off key 24b, write key 26, trouble reset key 28, and the like. Keys are arranged.

The operation of the conventional resistance welding control device having the configuration as described above is as follows.

First, when the power key 16 is turned on, the screen before the power is turned off is output on the liquid crystal display panel 12. When the menu key 20 of the keyboard 14 is selected, A list of display screens is displayed on the liquid crystal display panel 12 as shown in FIG.

In this case, when the cursor is moved by operating the cursors 22a to 22d on the screen of the liquid crystal display panel 12 and the recording key 26 is selected, the display screen is changed to set a desired welding condition. When a trouble occurs in the above operation, a screen indicating an error state is automatically output.

For example, in the case of selecting the start sw mode in FIG. 3, the format of the 4-bit signal to perform welding may be set. In the case of selecting the mode select, the up / on key 24a and By operating the down / off key 24b, you can define the maximum current capacity during welding.If you select the schedule, you can set the welding condition for each welding schedule and select the curr change%. In this case, you can set the rate at which the welding current steps up.If you select the step up count, you can set the number of energization of each step.If you select the monitor, the result of the welding schedule is determined according to the number of energization and the current. You can set the action to monitor.

The conventional resistance welding control device as described above has a frequency of 50 to 60 Hz and the thyristors 54A and 54B can be turned off only when the input power is OV, thereby making precise welding control impossible. A problem occurs.

In addition, since the screening work for the normal and abnormal results of the welding operation must be performed separately after performing the welding operation, the work becomes complicated and the reliability of the product is lowered.

The present invention has been made to solve the above problems, an object of the present invention is to provide a resistance welding control device to increase the frequency of the power source to enable precise welding control and to easily determine the welding results.

1 is a block diagram showing the configuration of a resistance welding control apparatus according to the prior art.

2 is a front view showing a liquid crystal display panel and a keyboard according to the prior art.

3 is a view showing a menu screen output to a liquid crystal display panel in the prior art.

4 is a block circuit diagram showing a configuration of a resistance welding control device according to the present invention.

5 shows a front panel of a device mounted to the present invention.

6 is a diagram showing an example of an initial screen displayed in the present invention.

7 is a timing diagram used in the present invention.

* Explanation of symbols for main parts of the drawings

110: liquid crystal display panel 120: keyboard

130: LED display unit 140: rectifier circuit unit

150: bridge circuit portion 160: driving circuit portion

170: control circuit 180: hall current sensor

190 pulse width modulation circuit portion 200 input / output circuit portion

210: control power supply 220: input / output (I / O) connector

230: connector for external monitoring 240: circuit breaker

300: welding transformer

In order to achieve the above object, the present invention provides a liquid crystal display panel for displaying an item on a screen so that various data can be changed and set, and a user can select each item to set welding conditions and the like. A keyboard for inputting a set value, an LED display unit for indicating the operating state of the system, a rectifier circuit unit for receiving a three-phase AC power source and converting it into a predetermined DC power source, and controlling the magnitude of the current output from the rectifier circuit unit for welding A bridge power switch circuit section (hereinafter referred to as a bridge circuit section) consisting of four transistors for supply to a transformer, a driving circuit section for controlling the operation of each transistor of the bridge circuit section, and a welding condition set through the keyboard A control circuit section for controlling the overall operation and an output terminal of the rectifier circuit section. And a Hall current sensor for sensing the magnitude of the current supplied to the welding electrode through the bridge circuit unit and the welding transformer, and controlling the operation of the driving circuit unit according to the output signal of the control circuit unit, but the welding current detected by the Hall current sensor. A pulse width modulation circuit part for controlling the operation of the driving circuit part according to the result of performing various calculations such as comparison determination of the measured value and the set value, and detecting whether there is a control signal input from the outside, and accordingly the operation signal in the control circuit part It provides a resistance welding control device comprising an input and output circuit unit for outputting.

According to an exemplary embodiment of the present invention, a control power supply unit receives input power and outputs a predetermined value of power used in the system, an input / output (I / O) connector connected to an external input / output device, operating states and results It includes an external monitoring connector connected to the external liquid crystal display panel to display.

In addition, each of the four transistors constituting the bridge circuit portion uses an Insulated Gate Bipolar Transistor (IGBT).

Hereinafter, exemplary embodiments of a resistance welding control apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a block circuit diagram showing the configuration of the present invention.

Referring to FIG. 4, reference numeral 110 denotes a liquid crystal display panel for displaying an item on a screen so that various data can be changed and set, and reference numeral 120 denotes an angle for setting welding conditions by the user. A keyboard for selecting an item and inputting a setting value is shown, and reference numeral 130 denotes an LED display indicating an operation state of the system.

In addition, reference numeral 140 denotes a rectifier circuit portion composed of a plurality of diodes and capacitors so as to receive a three-phase AC power input to a predetermined DC power, reference numeral 150 denotes the magnitude of the current output from the rectifier circuit portion 140. A bridge circuit portion consisting of four transistors so as to be controlled and supplied to the welding transformer 300 is shown. Reference numeral 160 denotes a driving circuit portion for controlling the operation of each transistor of the bridge circuit portion 150.

In addition, reference numeral 170 denotes a control circuit unit for controlling the operation of the entire system according to the welding conditions set through the keyboard 120, reference numeral 180 is mounted to the output terminal of the rectifier circuit unit 140 is the bridge circuit unit ( 150 and a Hall current sensor for detecting the magnitude of the current supplied to the welding electrode through the welding transformer 300, reference numeral 190 is the operation of the driving circuit unit 160 in accordance with the output signal of the control circuit unit 170 The pulse width modulation circuit unit controls the operation of the driving circuit unit 160 based on the result of performing calculations such as comparison of the welding current measurement value and the set value detected by the hall current sensor 180.

In addition, reference numeral 200 denotes an input / output circuit unit which detects whether there is a control signal input from the outside and outputs an operation signal to the control circuit unit 170 accordingly, and reference numeral 210 denotes an input power supply which is used in the system. Reference numeral 220 denotes an input / output (I / O) connector connected to an external input / output device. Reference numeral 230 denotes an operation state and a result of a system. An external monitoring connector is connected to an external monitoring device (not shown), and reference numeral 240 denotes a circuit breaker for determining ON / OFF of power supplied to the rectifier circuit 140. .

In this case, each of the four transistors constituting the bridge circuit 150 uses an Insulated Gate Bipolar Transistor (IGBT).

Referring to FIG. 5, the liquid crystal display panel 110, the keyboard 120, the LED display 130, and the power switch 240 are mounted on the front panel of the apparatus including the present invention.

In this case, the keyboard 120 is composed of a plurality of keys, OPERATE designating a welding execution board to start welding by a start input, PROGRAM designating a data setting mode to input data of each item, WELD to specify the welding output control mode to determine welding on / off, ◀, ▶ to determine the left and right movement of the cursor, and move the cursor to switch the welding conditions in OPERATE mode or PROGRAM mode. CNT / CLR, alarm and alarm output to make the counter displayed on the upper and lower sides of the liquid crystal display panel 110 in the operating mode, the mode to move to the mode position, and to clear the counter to zero in the program mode. It consists of RESET which releases the time, + which increases the term with the cursor by 1, and-which decreases the term with the cursor by 1.

In addition, the LED display unit 130 is composed of a plurality of LEDs that are mounted on each key of the keyboard 120 one by one and lit according to the operation and a plurality of LEDs lit according to the state of the system, in the welding standby state READY to be lit, START to be lit when welding start is input, ALARM to be flickered when abnormality occurs, + NG to be lit when output current is out of the upper limit, GO to be lit when output current is within the set error, output current + NG to be turned on when the deviation is lower than the set error, OPERATE to be turned on in operation mode, PROGRAM to be turned on in program mode, WELD to be turned on when welding output is available, MODE to be turned on in mode state, and liquid crystal counter. It consists of a CNT / CLR that lights up and lights up.

6 illustrates an example of an initial output screen of the liquid crystal display panel 110.

The liquid crystal display panel 110 displays welding conditions, welding progress conditions, and welding results of the system. During the welding, the average value of the welding current is displayed.

Referring to Fig. 6, the welding condition number MODE indicating the welding mode, LOAD indicating the energized current of the load during welding, CURR indicating the welding set current, LIMIT indicating the current monitoring range, and initial pressure time of the welding head are shown. SQZ indicative, HLD indicative of post-weld pressure holding time, and TIME indicative of welding time are output.

At this time, the time U1 representing the heat 1 welding rise time, H1 representing the heat 1 welding time, CO representing the cooling time, U2 representing the heat 2 welding rise time, and heat. (HEAT) 2 H2 representing the welding time is included.

In this case, the MODE may be set from mode 0 to mode 7 by the key operation of the keyboard 120, the CURR is the welding current of the heat 1 and the heat 2 to the set value of 1000A to 5000A, LIMIT is the current The monitoring function is displayed as a setting value of ± 00% to ± 99%, SQZ displays the initial pressurization time as the set value of 0 to 999ms, and HLD displays the pressure holding time after welding as the set value of 0 to 999ms.

Further, U1 of the welding time TIME is set from 0 to 99ms, H1 is set from 0 to 299ms, CO is set from 0 to 999ms, U2 is set from 0 to 99ms, and H2 is set from 0 to 299ms. do.

Referring to the operation of the present invention configured as described above in detail as follows.

The input three-phase AC power source 220V is changed into DC in the rectifier circuit unit 140 and turned on / off by a pulse width proportional to a set current in the bridge circuit unit 150 to weld heads through the welding transformer 300. The welding is performed by supplying with.

The user manipulates the keyboard 120 while viewing the screen displayed on the liquid crystal display panel 110 to change or set welding conditions.

The welding condition is input to the control circuit unit 170 to operate the system.

On the other hand, the pulse width modulation circuit unit 190 initially determines the operation of the driving circuit unit 160 according to the control signal input from the control circuit unit 170, and then the rectifying circuit unit 140 in the bridge circuit unit The welding current output to the welding electrode through the 150 and the welding transformer 300 is continuously detected by the hall current sensor 180 and compared with a set current in real time, and according to the result, the pulse of the driving circuit unit 160. Control the width to adjust the welding current. The driving circuit unit 160 controls each IGBT at a high frequency of 2 kHz. One HEAT operation is included in one welding operation.

As a result, the present invention enables precise welding to be performed by operating the four IGBTs according to the inverter control scheme.

Referring to the timing diagram of FIG. 7, the driving operation according to the inverter method will be described below.

Reference numeral T1 denotes an input sensing minimum time (10 ms) required for sensing an input after a welding START pulse is input, and T2 indicates a pressurized output after the input of the START pulse is detected. The pressurization output delay time (12ms) is taken, and T3 represents the initial pressurization time (0 to 999ms) after the pressurization output is started and before the welding current is output.

Further, reference numeral T4 denotes a welding execution time (1 to 1597 ms) for outputting a welding current to perform welding while the pressure output is in progress, and T5 denotes a time until the pressure output ends after the completion of the welding execution. The pressurization holding time (0 to 999 ms) is shown, and T6 indicates the judgment output delay time (5 ms).

In addition, reference numeral T7 denotes a determination output time (100 ms), T8 denotes an LCD load display delay time (5 ms), T9 denotes an alarm output delay time (4 ms), and T10 denotes a return. RESET Indicates minimum input detection time (30ms).

As a result, when the start pulse is input, after the T1 has elapsed, the input is sensed and the pressure output is instructed. When the pressurization output starts, the initial pressurization is performed during T3, and the welding current is output to perform the welding during T4.

When the welding is finished, the pressurized output is stopped after maintaining the pressurized state for T5. The LED and the judgment output are delayed for T6 after stopping the pressurizing output and made for T7, and the LCD LOAD indication is made for delaying for T8 after stopping the pressurizing output. At this time, the display of the LCD LOAD is released by the next start pulse.

In addition, the alarm output is delayed for T9 after the pressurization output is stopped, and the reset signal output after the operation is performed is detected after being delayed for T10.

Meanwhile, when an abnormality occurs in the above operation, the abnormality is displayed through the liquid crystal display panel 110, and when the welding operation is completed, the normal and abnormality of the welding result is determined according to the output welding current. The display is displayed on the liquid crystal display panel 110.

As described above, the welding control apparatus of the present invention uses an frequency of 2 kHz, so that the number of times that can be turned on / off during the welding operation is increased, thereby making it possible to perform precise welding control.

In addition, since the welding result is determined by comparing with a predetermined set value immediately after the welding operation is performed and displayed to the user, the sorting operation for normal and abnormality is facilitated.

Claims (3)

A liquid crystal display panel 110 for displaying items on a screen so that various data can be changed and set, and a keyboard 120 for selecting each item and inputting a set value for setting welding conditions by a user. ), An LED display unit 130 indicating an operation state of the system, a rectifier circuit unit 140 for receiving a three-phase alternating current power source and converting it into a predetermined DC power source, and a magnitude of the current output from the rectifier circuit unit 140. A bridge power switch circuit section (hereinafter referred to as a bridge circuit section) 150 consisting of four transistors so as to be controlled and supplied to the welding transformer 300, and a driving circuit section controlling the operation of each transistor of the bridge circuit section 150 ( 160 and the control circuit unit 170 for controlling the operation of the entire system according to the welding conditions set through the keyboard 120, and the output terminal of the rectifier circuit unit 140 A hall current sensor 180 mounted to detect a magnitude of a current supplied to the welding electrode through the bridge circuit unit 150 and the welding transformer 300, and the driving circuit unit according to an output signal of the control circuit unit 170. 160 to control the operation of the pulse width modulation to control the operation of the driving circuit unit 160 according to the result of performing various calculations, such as comparison of the welding current measurement value and the set value detected by the Hall current sensor 180 The circuit unit 190 detects the presence of a control signal input from the outside, and accordingly outputs an operation signal to the control circuit unit 170 and the predetermined value used in the system by receiving the input power and the input power. Resistance welding control device, characterized in that it comprises a control power supply 210 for outputting the power of the input and output (I / O) connector 220 connected to the fisherman's input and output device The resistance welding control device according to claim 1, further comprising an external monitoring connector (230) connected to an external monitoring device for monitoring the operation state and the operation result of the system. The resistance welding control apparatus according to claim 1, wherein each of the four transistors constituting the bridge circuit portion uses an Insulated Gate Bipolar Transistor (IGBT).

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