KR20010011223A - Power supply of 3 phase spot welder using digital phase angle control - Google Patents

Abstract

PURPOSE: A power device of a three phase spot welder using a digital phase angle control is provided to prevent a load from being concentrated on the power of any one phase. CONSTITUTION: The power device of a three phase spot welder is composed of a three phase periodic signal generator(100), a welding time generator(200), a welding current controller(300), a trigger signal generator(400), a three phase switching device(500) and a welding power supplier(600). With the periodic signal from the periodic signal generator, the trigger signal generator generates a trigger signal to switch three phase power. With the voltage of the three phase power, the welding power supplier supplies welding power to the spot welder by amplifying and rectifying current. The welding current controller outputs a welding current signal for the welding time set by the welding time generator.

Description

Power supply of 3 phase spot welder using digital phase angle control

The present invention relates to a power supply apparatus for a three-phase spot welder using a digital phase angle control to switch the three-phase power supply by rectifying the digital phase angle, rectifying and supplying welding power to the spot welder.

Since a general spot welder has a low welding voltage and a low welding resistance of 0?, The welding current changes abruptly with a slight change in the welding voltage, and as a result, the welding quality is different.

The amount of heat P generated at the welding spot in the case of spot welding can be approximated by the following equation.

In Equation 1, i is a welding current, R is a contact resistance of the welding point generated by the pressure that the spot welder pressurizes the weldment, and the resistivity of the weldment, and t is a welding time.

The welding current i is determined by the voltage output from the spot welder and the contact resistance R.

Here, in the case of spot welding, when the pressure pressurizing the weldment and the thickness and density of the weldment are assumed to be constant, this means that the contact resistance R is constant.

Therefore, assuming that the contact resistance R is constant, the welding current i and the welding time t must be kept constant in order to make the heat quantity P constant.

The welding current Since it is determined by the welding voltage V of the spot welding machine, the welding voltage V must be kept constant.

The spot welding machine using a conventional single phase power source secures a welding voltage by direct current or alternating current in a single phase manner in order to obtain a large current.

That is, the conventional spot welder switches the AC power of the R phase (or the S phase or the T phase) supplied from the columnar transformer 10 in the switching unit 12 as shown in FIG. 1, and steps down the transformer 14. And amplifying the current to supply welding power to the spot welder 16, or as shown in FIG. 2, rectifying the power output from the transformer 14 from the rectifier 20 into a pulse current supply to weld the spot welder 16. Power was supplied.

However, the above-described conventional schemes use only one phase power from among R-phase, S-phase, and T-phase three-phase power supplies supplied from the pole-phase transformer 10 (refer to using an R-phase power supply in the drawings of FIGS. 1 and 2). As an example, an excessive load is applied to an arbitrary one-phase power source to be used, which causes deformation of amplitude and distortion of the other two-phase power source that is not used, thereby degrading the quality of the power source. Of course, there was a problem incurring heavy investment costs of suppliers and consumers of commercial power.

In addition, there is a power supply for supplying power to the spot welder by using all three-phase power supplied from the main-phase transformer, but this is the power of any one-phase power (R phase, phase, S phase or T phase power) among the three phase power sources. A synchronization signal is generated based on the phase, a trigger signal of the switching element is obtained using the generated synchronization signal, and synchronization of the remaining two phases of power is generated and a trigger signal is generated based on the trigger signal.

Therefore, it is impossible to perform synchronous operation completely for three-phase power supply, and also use the same power supply as magnetic field induction by magnetic field generated around pulse transformer. In this case, the root mean square voltage may not be constant.

That is, as shown in FIG. 3, if any phase switching element as reference is triggered at time T1 and the trigger phase angle of the remaining two phase switching elements is made at time T2 or another position due to environmental reasons or some factor, Not only does each phase not operate in synchronization with each other, but also it cannot be concluded that the load sharing ratio of each phase is equal, which means that the RMS voltages are different.

Accordingly, an object of the present invention is to prevent the load from being biased to the power supply of any one of the three-phase power supplies, and to supply the power of a three-phase spot welder using digital phase angle control to uniformly apply the load to each of the three-phase power supplies. To provide a device.

It is another object of the present invention to provide a power supply apparatus for a three-phase spot welder using digital phase angle control that can eliminate malfunction caused by noise and influence of the three-phase power source from each other.

Another object of the present invention is to digitize the trigger position of the switching element according to the phase angle of the three-phase power source to ensure a stable welding current, improve the welding quality, increase the efficiency and utilization of commercial power source digital phase angle It is to provide a power supply of a three-phase spot welding machine using control.

According to the power supply apparatus of the three-phase spot welding machine using the digital phase angle control of the present invention for achieving the above object, by detecting the period of the three-phase power input to the three-phase period signal generating means, the positive phase signal, R phase of R phase Generates a negative periodic signal, a positive periodic signal of S phase, a negative periodic signal of S phase, a positive periodic signal of T phase and a negative periodic signal of T phase, and according to the generated three phase periodic signal, the trigger signal generating means Generate a trigger signal.

According to the trigger signal of each phase generated by the trigger signal generating means, the three-phase switching means switches the three-phase power supply, and the welding power supply means steps down the voltage of the three-phase power switched by the three-phase switching means and amplifies the current. It rectifies and supplies welding power to the spot welder.

In addition, the present invention includes a welding current control means for comparing the three-phase periodic signal and the welding current control signal generated by the three-phase periodic signal generating means and generating a welding current signal for each phase and the generated welding current signal By inputting to the trigger signal generating means as an input signal to limit the current of the welding power supply, and also having a welding time generating means generates a welding time signal for a preset time when the welding start signal is input and the welding time signal Only while the welding current control means outputs a welding current signal.

1 is a circuit diagram showing an example of a conventional spot welder,

2 is a circuit diagram showing another example of a conventional spot welder,

3 is a waveform diagram for explaining asynchronous operation in a conventional three-phase spot welder,

4 is an overall block diagram showing an embodiment of the power supply apparatus of the present invention;

5 is a detailed circuit diagram showing the configuration of the three-phase periodic signal generating means of FIG. 4;

6A to 6F are operation waveform diagrams of each part of FIG. 5;

7 is a detailed circuit diagram showing the configuration of the welding time generating means of FIG.

8A to 8G are operation waveform diagrams of each part of FIG. 7;

9 is a detailed circuit diagram showing the configuration of the welding current control means of FIG.

10A to 10R are operation waveform diagrams of each part of FIG. 9,

FIG. 11 is a detailed circuit diagram showing the configuration of the trigger signal generating means of FIG. 4; FIG.

12 is a detailed circuit diagram showing the configuration of the three-phase switching means and welding power supply means of FIG.

13A and 13B are waveform diagrams showing welding power supplied to an input three-phase power supply and a spot welder.

* Description of the symbols for the main parts of the drawings *

100: three-phase period signal generating means 200: welding time generating means

210: sync signal generator

211 to 216, 224, 323, and 326: monostable multivibrator

220: comparison means 221: flip-flop

222: counter 223: comparator

300: welding current control means 310: reference welding current generating unit

311 digital / analog converter 312 current / voltage converter

313 amplification unit 320, 330, 340: welding current output unit

321, 324: integrator 322, 325: comparator

400: trigger signal generating means 410, 420, 430: transformer

440 to 490: trigger signal generator 500: three-phase power supply switching means

600: welding power supply means 700: spot welder

RPI, R2PI, SPI, S2PI, TPI, T2PI: R phase, S phase and T phase plus and minus period signals

TIM: welding time signal

RI, R2I, SI, S2I, TI, T2I: welding current signal

RT, R2T, ST, S2T, TT, T2T: Trigger Signal

Hereinafter, the power supply apparatus of the three-phase spot welding machine using the digital phase angle control of the present invention will be described in detail with reference to the accompanying drawings of FIGS. 4 to 12.

4 is a block diagram showing an embodiment of a power supply apparatus of the present invention.

As shown therein, the period of the three-phase power input is detected to detect the positive period signal RP of R phase, the negative period signal R2PI of R phase, the positive period signal SPI of S phase, and the negative period signal S2PI of S phase. A three-phase periodic signal generating means 100 for generating a positive periodic signal TPI and a negative periodic signal T2PI for T phase, and the three-phase periodic signal generating means 100 when a welding start signal is input; Welding time generation means 200 for generating a welding time signal TIM for the welding time set according to the welding time control signal while determining the welding time with the generated periodic signals RPI, R2PI, SPI, S2PI, TPI, T2PI. ) And the periodic signals RPI, R2PI, SPI, S2PI, TPI, T2PI output by the three-phase periodic signal generating means 100 while the welding time generating means 200 generates the welding time signal TIM. ) And welding current control signals to compare welding current signals (RI, R) for each phase Welding current control means 300 for generating 2I, SI, S2I, TI, T2I, and welding current signals RI, R2I, SI, S2I, TI, T2I output by the welding current control means 300; Trigger signal generating means 400 for generating a trigger signal (RG1, RK1, RG2, RK2, SG1, SK1, SG2, SK2, TG1, TK1, TG2, TK2) according to the three-phase power source, and the trigger signal Three-phase switching for switching the three-phase power supply according to the trigger signal (RG1, RK1, RG2, RK2, SG1, SK1, SG2, SK2, TG1 TK1, TG2, TK2) for the three-phase power generating unit 400 Welding power supply means 600 for supplying welding power to the spot welder 700 by stepping down the voltage of the means 500 and the three-phase power source switched and output from the three-phase switching means 500, amplifying the current, and rectifying the rectifier. It is composed of

In the power supply apparatus of the three-phase spot welding machine of the present invention configured as described above, when the three-phase power is input, the three-phase periodic signal generating means 100 has a three-phase power supply, that is, a cycle of the R-phase power, S-phase power, and T-phase power. R phase plus period signal (RPI), R phase min period signal (R2PI), S phase plus period signal (SPI), S phase minus period signal (S2PI), T phase plus period signal (TPI) and T phase minus Each period signal T2PI is generated and output.

When the operator inputs a welding start signal for spot welding in this state, the welding time generating means 200 is a periodic signal (RPI, R2PI, SPI, SPI, S2PI, output from the three-phase periodic signal generating means 100, The welding time signal TIM is generated during the predetermined welding time set according to the welding time control signal while the welding elapsed time is determined by TPI and T2PI).

The welding time signal TIM is input to the welding current control means 300. The welding current control means 300 outputs the three-phase periodic signal generating means 100 while the welding time signal TIM is input. Compare the periodic signals (RPI, R2PI, SPI, S2PI, TPI, T2PI) with the welding current control signals, and compare the welding current signals (RI, R2I, SI, S2I, TI, T2I) for each phase according to the comparison result. Will occur.

In this way, the trigger signal generating means 400 generates the trigger signals RT, R2T, ST, and the like according to the welding current signals RI, R2I, SI, S2I, TI, and T2I generated by the welding current control means 300. S2T, TT, T2T), and the three-phase switching means 500 is three according to the generated trigger signals RG1, RK1, RG2, RK2, SG1, SK1, SG2, SK2, TG1, TK1, TG2, and TK2. The phase power is switched and output.

As described above, the three-phase power that is switched and output from the three-phase switching means 500 is rectified by DC power after the voltage is stepped down by the welding power supply means 600 and the current is amplified to supply the welding power to the spot welder 700. Done.

The power supply device of the three-phase spot welding machine of the present invention will be described in more detail with reference to FIGS. 5 to 12.

5 is a detailed circuit diagram showing the configuration of the three-phase periodic signal generating means 100 of FIG.

As shown therein, between the R phase power source and the S phase power source, between the S phase power source and the T phase power source, and between the T phase power source and the R phase power source, the resistors R100 to R102 and the reverse diodes D100 to D102 ) Are connected in series, and the light emitting elements of the photo couplers PC100 to PC102 are connected in parallel to the reverse diodes D100 to D102 in opposite directions.

Then, the power supply B + is connected to the collectors of the light receiving elements of the photocouplers PC100 to PC102 via resistors R103 to R105, respectively, and inverters IV100 and IV103 (IV101 and IV104) (IV102) at their connection points. IV105) are respectively connected in series.

The three-phase periodic signal generating means 100 configured as described above has a three-phase power supply when the three-phase power supply of the R-phase, S-phase, and T-phase is input, according to the phase of the three-phase power supply of the R-phase, S-phase, and T-phase. The light emitting element of the PC102 is selectively lit to output light, and the light receiving element receives the light output by the light emitting element of the photo coupler PC100 to PC102 and is turned on and off, thereby collecting the R phase, S phase and T phase. It outputs a pulse signal according to the phase.

That is, the photo coupler PC100 operates when the magnitude of the R phase power is larger than that of the S phase power and outputs a high potential pulse signal, and the photo coupler when the magnitude of the S phase power is larger than that of the T phase power. The PC101 operates to output a high potential pulse signal, and when the magnitude of the T phase power is larger than that of the S phase power, the photo coupler PC102 operates to output the high potential pulse signal.

The pulse signals respectively output from the photo couplers PC100 to PC102 are waveform-shaped while being inverted through the inverters IV100 to IV102, and are again inverted by the inverters IV103 to IV105 and outputted after being waveform-shaped. IV100 outputs the positive period signal RP on R and the negative period signal R2PI on R as shown in FIGS. 6A and 6B, and inverters IV104 and IV101 are shown in FIGS. 6C and 6D. As shown, the positive period signal SPI of S phase and the negative period signal S2PI of S phase are outputted, and the inverters IV105 and IV102 are the positive period signal TPI of T phase as shown in FIGS. 6E and 6F. ) And T phase negative signal (T2PI), respectively.

7 is a detailed circuit diagram showing the configuration of the welding time generating means 200 of FIG.

As shown therein, the welding time generating means 200 according to the present invention includes the positive phase signal RP of R phase, the negative periodic signal R2PI of R phase, and the positive phase of S phase generated by the three-phase periodic signal generator 100. A synchronization signal generator 210 for generating a synchronization signal of a three-phase power source according to the periodic signal SPI, the negative periodic signal S phase of S phase, the positive periodic signal T phase of T phase, and the negative periodic signal T2PI of T phase, and When the welding start signal is input, the synchronization signal generator 210 counts the number of synchronization signals of the three-phase power source, and counts the number of three-phase power synchronization signals and the value of the preset welding time control signal. Comparing means 220 for generating a welding time signal TIM during the welding time set as the welding time control signal while comparing.

The synchronization signal generator 210 is inputted with a positive period signal R phase of R, a negative period signal R2PI of R phase, a positive period signal S phase of S phase, a negative period signal S phase of S phase S2, and a positive phase of T phase. The monostable multivibrators 211 to 216 that are triggered in accordance with the periodic signal TPI and the negative phase signal T2PI of the T phase to generate pulse signals, and the pulse signals output by the monostable multivibrators 211 to 216. The OR is composed of OR gate which outputs the synchronous signal of the three-phase power supply by logical sum.

The comparison means 220 includes a NAND gate NAND221 and an NAND gate NAND222 and NAND223 flip-flop to inversely multiply the synchronous signal and the welding start signal of the three-phase power source output from the OR gate OR211. A flip-flop 221 connected to output a clock signal and a welding time signal TIM according to an output signal and a reset signal RST of the NAND gate NAND221, the welding time signal TIM and the OR gate A NAND gate NAND224 that generates an enable signal by inverting and logically multiplying the output signal of OR211, a clock signal that is cleared according to the reset signal RST, and the flip-flop 221 outputs the NAND gate A counter 222 for performing an enable and count operation according to the enable signal output from the NAND224, and a comparator 223 for comparing the count value of the counter 222 and the value of a welding time control signal set by a user. Wow, A monostable multivibrator 224 that is triggered according to the welding start signal to generate a pulse signal, and an output signal of the comparator 223 and an output signal of the monostable multivibrator 224 are logically summed to reset the signal. Or a OR gate OR221 for outputting RST.

The welding time generating means 200 according to the present invention configured as described above has the positive phase signal RP of R phase, the negative periodic signal R2PI of R phase, and the positive period signal S of S phase generated by the three phase periodic signal generating means 100 ( SPI), S-phase negative period signal (S2PI), T-phase positive period signal (TPI) and T-phase negative period signal (T2PI), respectively, the monostable multivibrators 211 to 216 of the synchronization signal generator 210 are triggered. As shown in Figs. 8A to 8F, R, S, and T phase synchronization signals (RS, R2S, SS, S2S, TS, T2S) are respectively generated, and the generated synchronization signals (RS, R2S, SS, S2S) are generated. , TS and T2S are logically summed and output from the OR gate OR211 as shown in FIG. 8G.

In this state, when the user operates a welding switch (not shown in the drawing) or the like and a welding start signal is input, the monostable multivibrator 224 of the comparing means 220 is triggered according to the input welding start signal. The pulse signal is output, and the output pulse signal is output as the reset signal RST through the OR gate OR221, so that the counter 222 is cleared, and the reset signal RST is set to the flip-flop 221. It is applied to the NAND gate NAND223.

Then, when the OR gate outputs the high potential reset signal and then outputs the low potential, the flip-flop 221 is reset so that the NAND gate NAND222 outputs the high potential and the NAND gate. The NAND223 outputs a low potential.

In this state, if the NAND gate NAND221 multiplies inversely the synchronous signal and the welding start signal of the three-phase power output from the OR gate OR211 to output the low potential, the NAND gate NAND222 is low in contrast to the above. The potential is output and applied to the clock terminal CLK of the counter 222 as a clock signal, and the NAND gate NAND223 outputs the welding time signal TIM of high potential, and the high voltage output from the NAND gate NAND223. According to the welding time signal TIM, the NAND gate NAND224 inverts the output signal of the OR gate OR211 and is applied to the enable terminal EN of the counter 222.

Here, the counter 222 converts a signal applied to the enable terminal EN to a low potential while a low potential is applied to the clock terminal CLK using, for example, a chip number '4518' which is a CMOS element. The counter 222 adds counts the falling period of the pulse signal applied to the enable terminal EN and outputs a count value to the input port B of the comparator 223. Is entered.

The welding time control signal input to the input port A of the comparator 223 is preset according to the time when the user performs spot welding, for example, by setting a welding time control signal using a dip switch or the like, or by using a micro As input from control means such as a computer (not shown in the figure), the comparator 223 compares the set welding time control signal with the count value of the counter 222.

In this state, when the set value of the welding time control signal is equal to the count value of the counter 222, the comparator 223 outputs the high potential to the output terminal A = B, and the output high potential is The counter 222 is cleared and the flip-flop 221 is reset so that the NAND gate NAND223 outputs a low potential, and the NAND gate NAND222 is high potential. Will print

That is, the welding time generating means 200 counts the synchronization signal output from the synchronization signal generator 210 when the welding start signal is input, and the counter 222 sets the welding time control signal. While the value is counted, the welding time signal TIM is output at high potential to perform spot welding during the welding time signal TIM of the high potential.

9 is a detailed circuit diagram showing the configuration of the welding current control means 300 of FIG.

As shown therein, the welding current control means 300 of the present invention includes a reference welding current generator 310 for outputting a reference welding current CUR according to a welding current control signal, and the reference welding current generator 310. ) Plus and minus period signals (RPI, R2PI), plus and minus period signals (SPI, S2PI), and plus and minus period signals (TPI, T2PI) of R phase according to the reference welding current (CUR) R phase, S phase and T phase welding current output section for outputting R phase welding current signals (RI, R2I), S phase welding current signals (SI, S2I) and T phase welding current signals (TI, T2I). And 320, 330, and 340.

The reference welding current generator 310 has an output terminal of the digital / analog converter 311 for converting an input welding current control signal into an analog current according to a reference voltage, and a non-inverting input terminal of the operational amplifier OP312 (+). The output terminal of the operational amplifier 0P312 is feedback-connected to its non-inverting input terminal (+), so that the current / voltage converter 312 is configured.

The output terminal of the current / voltage converter 312 is connected to the non-inverting input terminal (+) of the operational amplifier OP313 through the resistor R313, and the output terminal of the operational amplifier OP313 is connected to the resistor R314 through the resistor R314. The amplifier 313 is configured to be feedback-connected to R315 and its inverting input terminal + to output the reference welding current CUR through the resistor R316 at the output terminal of the operational amplifier OP313.

The R phase welding current output unit 320 is connected such that a negative period signal R2PI of R phase is applied to the base of the transistor Q320 through a resistor R321, and a positive period of R phase is connected to the collector of the transistor Q320. The signal RPI and the power supply B + are connected to each other through the resistors R320 and R322, and their connection points are connected to the non-inverting input terminal (+) of the ground capacitor C320 and the operational amplifier OP320, The output terminal of the operational amplifier OP320 is feedback-connected to the ground resistor R324 and its inverting input terminal (+) through a resistor R323 and a capacitor C321 connected in parallel to form an integrator 321.

The output terminal of the integrator 321 is connected to the non-inverting input terminal (+) of the comparator CP320 through the resistor R325, and the reference welding current CUR output by the reference welding current generator 310 is a resistor. An inverting input terminal (-) of the comparator CP320 is connected to the output terminal of the comparator CP320, and a power supply B + is connected to the output terminal of the comparator CP320 so as to be applied through a resistor R327. Is composed.

The output terminal of the comparator 322 is connected to the trigger terminal of the monostable multivibrator 323, and the output signal of the monostable multivibrator 323 is a reference welding current (the output of the reference welding current generator 310). CUR) and the welding time signal TIM outputted by the welding time generating means 200 are connected to be applied to the input terminal of the AND gate AND320 so that the welding current signal of the R phase at the output terminal of the AND gate AND320 ( RI) is configured to be output.

The positive period signal RPI of R phase is connected to be applied to the base of transistor Q321 through resistor R329, and the negative period signal R2PI of R phase and power supply B + are connected to the collector of transistor Q321. (R328) and (R330) are connected to each other so that the connection point is connected to the ground capacitor (C322) and the non-inverting input terminal (+) of the operational amplifier (OP321), the output terminal of the operational amplifier (OP321) is connected in parallel The integrator 324 is configured by feedback connection to the ground resistor R332 and its inverting input terminal (-) through the resistor R331 and the capacitor C323.

The output terminal of the integrator 324 is connected to the non-inverting input terminal (+) of the comparator CP321 through the resistor R333, and the reference welding current CUR output by the reference welding current generator 310 is a resistor. An inverting input terminal (-) of the comparator CP321 is connected to the output terminal of the comparator CP321 via R334, and a power supply B + is connected to the output terminal of the comparator CP321 so as to be applied through a resistor R335. Is composed.

The output terminal of the comparator 325 is connected to the trigger terminal of the monostable multivibrator 326, and the output signal of the monostable multivibrator 326 is a reference welding current outputted by the reference welding current generator 310. CUR) and the welding time signal TIM outputted by the welding time generating means 200 are connected to be applied to the input terminal of the AND gate AND321, so that the welding current signal of R phase at the output terminal of the AND gate AND321 is connected. R2I) is configured to be output.

In addition, the S-phase and T-phase welding current output units 330 and 340 are configured in the same manner as the R-phase welding current output unit 320, and the S-phase welding current signals SI and S2I and the T-phase welding current signals, respectively. Outputs (TI, T2I).

The welding current control means 300 of the present invention configured as described above converts the input digital welding current control signal into an analog current by the digital / analog converter 311 of the reference welding current generator 310 based on the reference voltage. The analog current converted by the digital / analog converter 311 is converted into a voltage through the operational amplifier OP312 of the current / voltage converter 312 and then amplified by the operational amplifier OP313 of the amplifier 313. Output by welding current (CUR).

As shown in FIG. 10B, the transistor Q320 of the integrator 321 of the R-phase welding current output unit 320 is turned on and off in response to the negative phase signal R2PI of the R phase input thereto, as shown in FIG. 10A. The positive period signal RPI and power supply B + of R phase input together are firstly integrated by the resistors R320 and R322 and the capacitor 320, and the resistors R323 and R324 and the capacitor in the operational amplifier OP320. According to the time constant of C321, as shown in FIG. 10G, the second integration is converted into a sawtooth wave.

The sawtooth wave output from the integrator 321 is applied to the non-inverting input terminal (+) of the comparator CP320 through the resistor R325 of the comparator 322, and the reference welding current generator 310 is output. The reference welding current CUR is applied to the inverting input terminal (-) of the comparator CP320 through the resistor R326.

Then, the comparator CP320 compares the sawtooth wave output from the integrator 321 and the reference welding current CUR, and a high value is obtained when the value of the sawtooth wave output from the integrator 321 is greater than that of the reference welding current CUR. The output above, and the monostable multivibrator 323 is triggered according to the output high potential to output a pulse signal as shown in Figure 10m.

At this time, when the plus period signal RPI on R has a high potential, and the welding time generating means 200 outputs the welding time signal TIM at high potential as the welding time, the monostable multivibrator 323 The output pulse signal is output as the welding current signal RI through the AND gate AND320.

As shown in FIG. 10A, the transistor Q321 of the integrator 324 is turned on and off according to the positive period signal RPI of R phase input as shown in FIG. 10A, and the negative period signal R2PI of R phase input as shown in FIG. 10B. ) And power source B + are first-integrated by resistors R328 (R330) and condenser C322, and according to the time constants of resistors R331 and R332 and condenser C323 in the operational amplifier OP321. As shown in Fig. 2, the second integration is converted into a sawtooth wave.

The sawtooth wave output from the integrator 324 is applied to the non-inverting input terminal (+) of the comparator CP321 through the resistor R333 of the comparator 325, and the reference welding current generator 310 is output. The reference welding current CUR is applied to the inverting input terminal (-) of the comparator CP321 through the resistor R334.

Then, the comparator CP321 compares the sawtooth wave output from the integrator 324 and the reference welding current CUR, and a high value is obtained when the value of the sawtooth wave output from the integrator 324 is greater than that of the reference welding current CUR. The monostable multivibrator 326 is triggered according to the high potential output and outputs a pulse signal as shown in FIG. 10N, and the pulse signal output by the monostable multivibrator 326 is an AND gate ( AND321 is output as the welding current signal (R2I).

In addition, the S-phase and T-phase welding current output units 330 and 340 include the positive and negative period signals SPI and S2PI of the S phase and the positive and negative period signals TPI of the T phase as shown in FIGS. 10C to 10F. , T2PI) is integrated as shown in FIGS. 10i to 10l and then compared with a reference welding current (CUR), and the monostable multivibrators 323 and 326 are triggered according to the comparison result to As shown, the welding current signals SI and S2I (TI and T2I) of the S and T phases are output.

That is, the welding current control means 300 includes the positive and negative periodic signals RI and R2PI of R phase and the positive and negative phases of S phase according to the magnitude of the welding current control signal while the high potential welding time signal TIM is generated. R, S and T phase welding current signals (RI, R2I) (SI, S2I) (TI, T2I) at the periodic positions of the negative periodic signals (SPI, S2PI) and the positive and negative periodic signals (TPI, T2PI) of the T phase. ) Will be printed.

FIG. 11 is a detailed circuit diagram showing the configuration of the trigger signal generating means of FIG.

As shown therein, a light emitting element of the resistor R400 and the photo coupler PC400 are connected in series between the power source B + and the R phase welding current signal RI, and the step-down transformer 410 for stepping down the R phase power source. The trigger signal RG1 of the S phase is output from the secondary coil of the resistor, and the resistor R403 and the capacitor C402 connected in parallel with the capacitor C401 are connected in parallel to the secondary coil of the step-down transformer 410. The secondary coil of 410 is connected to the gate of the diode D400, the capacitor C400, the resistor R402, and the thyristor SCR400 through the resistor R401 and the light receiving element of the photo coupler PC400. The R phase first trigger signal generator 440 is configured to output the S phase first cathode signal RG1 at the cathode of the SCR400.

In addition, the R phase second trigger signal generator 450, the S phase first and second trigger signal generators 460 and 470, and the T phase first and second trigger signal generators 480 and 490 are connected to the R phase. It is configured in the same configuration as the first trigger signal generator 440, and trigger signals RG2 and RK2 according to the output power of the step-down transformers 420 and 430 for stepping down the S-phase power and the T-phase power, respectively. And outputs SK1, SG2, SK2) (TG1, TK1, TG2, TK2).

The trigger signal generating means 400 configured as described above causes the step-down transformer 410 to step down the input R-phase power supply to, for example, about 26V and output the trigger signal RG1.

In this state, when the R-phase welding current signal RI is input at a low potential, the light emitting device of the photocoupler PC400 is turned on and the light receiving device is operated so that the output power of the step-down transformer 410 is a resistor (R400). And a light receiving element of the photo coupler PC400 to the gate of the thyristor SCR400.

Then, the thyristor SCR400 is triggered to be in a conductive state, and the output power of the step-down transformer 410 is output as the trigger signal RK1 through the thyristor SCR400.

The R-phase second trigger signal generator 450, the S-phase first and second trigger signal generators 460 and 470, and the T-phase first and second trigger signal generators 480 and 490 may be R-shaped. The phase first trigger signal generator 440 also operates in the same manner as the R phase first trigger signal generator 440 to trigger signals RG2 and RK2 (SG1, SK1, SG2, and SK2) (TG1, TK1, and TG2). , TK2) will be output respectively.

12 is a detailed circuit diagram showing the configuration of the three-phase switching means and welding power supply means of FIG.

As shown in the drawing, the thyristors SCR501, SCR502, SCR511, and SCR512 are connected in parallel and opposite directions to the R-phase power source, the S-phase power source, and the T-phase power source, respectively. (SCR502) (SCR511, SCR512) (SCR521, SCR522) (SCR521, SCR522) trigger signal (SG1, SK1, RG2, RK2) (SG1, SK1, SG2, SK2) output by the trigger signal generating means 400 ( The switching means 500 is configured such that TG1, TK1, TG2, and TK2 are applied.

The three-phase power source switched by the switching means 500 causes the voltage to be stepped down by the transformer 610 and the current amplification, and the secondary side power source of the transformer 610 is the diodes D601 and D602 (D611 and D612). (D621, D622) is a full-wave rectification to supply the welding power to the spot welder (700).

As described above, in the three-phase switching means 500 and the welding power supply means 600 configured as described above, the trigger signal generating means 400 includes the trigger signals SG1, SK1, RG2, and RK2 (SG1, SK1, SG2, SK2). In case of outputting (TG1, TK1, TG2, TK2), the Dyistor (SCR501, SCR502) (SCR511, SCR512) (SCR521, SCR522) of the three-phase switching means 500 is operated so that the R phase power source and the S phase power source And switching the T phase power source, the switched R phase power source, the S phase power source and the T phase power source are stepped down by the transformer 610 of the welding power supply unit 600, and current amplified and output. The output power is respectively rectified by diodes D601 and D602 (D611 and D612) (D621 and D622) and is shown in FIG. 13B for the three-phase power input to the spot welder 700 as shown in FIG. 13A. As described above, three-phase welding power is supplied.

On the other hand, in the above described while the welding power supply to the three-phase power supply to adjust the welding time and the welding current as an example.

In the present invention, the present invention is not limited thereto, and the positive phase signal RP of R phase, the negative periodic signal R2PI of R phase, the positive period signal SPI of S phase, Spot welding may be performed by inputting the negative periodic signal S2PI of S phase, the positive periodic signal TPI of T phase, and the negative periodic signal T2PI of T phase directly to the trigger signal generating means 400, and also welding current. It should be understood that various modifications can be made within the technical scope of the present invention, such as having a control means 300 to control the welding current of spot welding.

As described in detail above, the present invention supplies the welding power to the spot welder using all three phase powers, thereby imparting a uniform burden on the three phase powers, and thus has no effect on other equipment using the three phase powers. In addition, it is possible to stabilize the amplitude of the three-phase power source, as well as to improve the quality of the three-phase power source and to reduce the investment cost of the commercial power supplier and the customer.

Claims (13)

Three-phase detecting the input three-phase power supply cycle and generating positive phase signal of R phase, negative period signal of R phase, positive period signal of S phase, negative period signal of S phase, positive period signal of T phase and negative period signal of T phase Periodic signal generating means; Trigger signal generating means for generating a trigger signal for switching a three-phase power source according to the three-phase periodic signal generated by the three-phase periodic signal generating means; Three-phase switching means for switching a three-phase power source in accordance with a trigger signal of each phase generated by the trigger signal generating means; And Three-phase spot welder using digital phase angle control, characterized in that it consists of a welding power supply means for supplying welding power to the spot welder by stepping down the voltage of the three-phase power source switched in the three-phase switching means, amplifying the current and rectified Power supply. The apparatus of claim 1, wherein the three-phase periodic signal generator; A plurality of photo couplers for generating pulse signals while the operation is controlled according to the values of the R phase power source and the S phase power source, the S phase power source and the T phase power source, and the T phase power source and the R phase power source; And Waveform shaping and inverting the pulse signal respectively output by the plurality of photo couplers outputs the negative periodic signal of R phase, the negative periodic signal of S phase, and the negative periodic signal of T phase, and again the waveform shaping and inversion of the positive periodic signal of R phase. And a plurality of inverters outputting a positive period signal of S phase and a positive period signal of T phase. The method of claim 1, wherein the trigger signal generating means; Each of the three phase power inputs is stepped down to perform the first and second gate trigger signals for the R phase, the first and second gate trigger signals for the S phase, and the first and second gate trigger signals for the T phase. Generating a plurality of transformers; And A plurality of first and second cathode trigger signals for R phase, first and second cathode trigger signals for S phase, and first and second cathode trigger signals for T phase according to an input signal, respectively; A trigger signal generator of The plurality of trigger signal generators; A photo coupler operating according to an input signal; And And a thyristor that is operated according to the output signal of the photocoupler to generate a trigger signal. The method of claim 1, wherein the three-phase switching means; Using a digital phase angle control, comprising a plurality of thyristors provided in parallel and opposite directions to each other and selectively operating according to a plurality of trigger signals output by the trigger signal generating means to switch three-phase power respectively. Power supply for three-phase spot welder. According to claim 1, The welding power supply means; A three-phase transformer for stepping down the voltage of the three-phase power source which is switched and output by the three-phase switching means and amplifying the current; And Power supply of the three-phase spot welding machine using a digital phase angle control, characterized in that consisting of a plurality of diodes to rectify the output power of the three-phase transformer to output the welding power. The method of claim 1, Welding to generate a welding current signal for each phase by comparing the three-phase periodic signal generated by the three-phase periodic signal generating means and the welding current control signal and input the generated welding current signal to the trigger signal generating means as an input signal. Power supply of a three-phase spot welding machine using a digital phase angle control, characterized in that it comprises a current control means. According to claim 6, The welding current control means; A reference welding current generator for outputting a reference welding current according to a welding current control signal; And Digital phase characterized in that it comprises a plurality of welding current output unit for outputting the welding current signal for the positive and negative period signal of the R phase, S phase and T phase according to the level of the reference welding current generated by the reference welding current generation unit Power supply of three-phase spot welding machine using each control. The method of claim 7, wherein the reference welding current generating unit; A digital / analog converter for converting an input welding current control signal into an analog current; A current / voltage converter for converting the output current of the digital / analog converter into a voltage; And Power supply of the three-phase spot welding machine using a digital phase angle control, characterized in that the amplifier configured to amplify the output voltage of the current / voltage converter to output a reference welding current. The method of claim 7, wherein the plurality of welding current output unit; An integrator for integrating a plurality of periodic signals generated by said three-phase periodic signal generating means and converting them into sawtooth waves; A comparison unit comparing the output signal of the integrator with a reference welding current generated by the reference welding current generating unit; A monostable multivibrator that is triggered according to the output signal of the comparator and generates a pulse signal; And And an AND gate for outputting the output signal of the monostable multivibrator as a welding current signal of a corresponding period during a period of a corresponding periodic signal among a plurality of periodic signals generated by the three-phase periodic signal generating means. Power supply of three-phase spot welding machine using phase angle control. The method according to any one of claims 6 to 9, And a welding time generating means for generating a welding time signal for a preset time when the welding start signal is input and causing the welding current control means to output a welding current signal only during the welding time signal. Power supply of three-phase spot welding machine using phase angle control. The method of claim 10, wherein the welding time generating means; A synchronization signal generator for generating a synchronization signal of a three-phase power source in accordance with a periodic signal generated by the three-phase periodic signal generator; And When the welding start signal is input, the welding is performed while counting the number of synchronizing signals of the three-phase power source generated by the synchronizing signal generator and comparing the counted number of three-phase power synchronizing signals with a value of a preset welding time control signal. A power supply for a three-phase spot welding machine using digital phase angle control, characterized in that the comparison means for generating a welding time signal for a time. 12. The apparatus of claim 11, wherein the synchronization signal generator; A plurality of monostable multivibrators, each triggered according to a periodic signal generated by the three-phase periodic signal generator to generate a pulse signal; And And a OR gate configured to logically sum pulse signals generated by the plurality of monostable multivibrators and output them as a synchronization signal of a three-phase power source. 3. 12. The apparatus of claim 11, wherein the comparing means comprises: A first NAND gate inverting and logically multiplying a synchronous signal and a welding start signal of a three-phase power source output by the synchronous signal generator; A flip-flop for outputting a clock signal and a welding time signal according to the output signal and the reset signal of the first NAND gate; A second NAND gate generating an enable signal by inverting and logically multiplying the welding time signal and the output signal of the synchronization signal generator; A counter that is cleared according to a reset signal and counts the time at which the welding time signal is generated by performing an enable and count operation according to a clock signal output by the flip-flop and an enable signal output by the NAND gate; A comparator for comparing the count value of the counter and a value of a welding time control signal set by a user; A monostable multivibrator that is triggered according to the welding start signal to generate a pulse signal; And And an OR gate for outputting the reset signal by logically adding the output signal of the comparator and the output signal of the monostable multivibrator.