JP5618850B2 - Welding power supply and welding machine - Google Patents

Description

  The present invention relates to a welding power source apparatus that performs feedback control based on calculation of an electrode tip voltage and a welding machine including the welding power source apparatus.

  For example, as disclosed in Patent Document 1, the arc welding power source device converts DC power obtained by rectifying AC input power from a commercial power source into high-frequency AC power using an inverter circuit, and the voltage is adjusted by a welding transformer. The high frequency AC power is converted into DC output power suitable for arc welding by a rectifier circuit and a DC reactor. The output power generated by the power supply device is supplied to the electrode supported by the torch, whereby an arc is generated between the electrode tip and the welding target, and welding of the welding target is performed.

  Further, such a welding power supply device detects the output current and the output voltage, and the control device feeds back the output current and output voltage detected at that time to the PWM control of the inverter circuit. Improvement of welding performance is aimed at by carrying out control which makes the output electric power of an appropriate value.

JP-A-8-103868

  By the way, in order to generate a suitable arc, not only the output voltage detected in the power supply device is reflected in the control value of the inverter circuit but also the tip voltage of the electrode where the arc is generated is calculated and calculated. It is preferable to reflect the measured electrode tip voltage in the control value.

  This is because, in practice, the torch (electrode) for welding and the power supply device are often separated from each other, and the two are generally connected via a power cable. is there. Therefore, since the cable length of the power cable differs for each user, not only the resistance value of the cable itself is different, but also when the cable is laid in a straight line, for example, when the cable is laid around the extra length, for example, And the inductance value varies depending on the number of laps. For this reason, in order to further improve the welding performance, the voltage variation of the resistance and the inductance between the power cable and the electrodes outside the power supply device cannot be ignored.

  Therefore, in the aspect in which the output voltage detected in the power supply device is reflected in the control value of the inverter circuit, the voltage value deviating from the true electrode tip voltage is reflected in the control value of the inverter circuit. There is a concern that it may hinder the generation of a suitable arc and hinder further improvement in welding performance.

  The measurement of the resistance value and the inductance value used for the calculation of the electrode tip voltage is performed in a state where the electrode tip is short-circuited. However, in the case of a short circuit abnormality (short circuit failure), the measurement error of the resistance value and the inductance value is large. The value of the tip voltage calculated using these becomes low in accuracy. Similarly, if the tip of the electrode is abnormally short-circuited, an arc may occur unexpectedly at the tip of the electrode, so that when there is a worker near the electrode, the worker is uneasy.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to maintain a short circuit abnormality when measuring the resistance value and the inductance value used for the calculation of the electrode tip voltage while the electrode is in a short circuit state. Another object of the present invention is to provide a welding power supply device capable of preventing measurement at a temperature and a welding machine including the welding power supply device.

  In order to solve the above-mentioned problems, an invention according to claim 1 is directed to an inverter circuit that converts DC power into high-frequency AC power, a welding transformer that adjusts the voltage of the converted AC power, and a secondary side of the welding transformer. DC conversion means for generating DC output power suitable for welding from AC power, and generating an arc for welding with the welding object based on supply of the generated output power to the electrode And a welding means further comprising a control means for calculating the tip voltage of the electrode based on the output current and the output voltage detected by the detection means in the apparatus, and controlling the inverter circuit based on the calculated tip voltage. A power supply apparatus, wherein the electrodes are short-circuited, and the electrodes are based on a voltage value of the output voltage when the output current generated by the operation of the inverter circuit is a predetermined current value. A resistance value calculating means for calculating a total resistance value on the path to the end; and a current attenuation amount when the output current generated in the operation of the inverter circuit is set to a predetermined current value when the electrodes are short-circuited And a measurement mode for executing a process including an inductance value calculation means for calculating a total inductance value on a path to the electrode tip based on the voltage value of the output voltage detected by the detection means A tip voltage calculating means for calculating the tip voltage by correcting a voltage change applied to the total resistance value and the total inductance value on the path to the tip of the electrode, and during actual measurement in the measurement mode; A short-circuit abnormality determination unit that determines whether the output voltage detected by the detection unit is an abnormal value due to a factor including a short-circuit abnormality of the electrode; Abnormal if it is determined that further comprising an abnormality informing means for informing to that effect and its gist.

  In the present invention, in the measurement mode for measuring the total resistance value and the total inductance value up to the electrode tip for calculating the electrode tip voltage, the detected output voltage includes an electrode short-circuit abnormality during actual measurement of each measured value. The short circuit abnormality determining means determines whether or not the abnormal value is due to the factor. When it is determined that the short circuit abnormality determination unit is abnormal, the abnormality notification unit notifies the abnormality. As a result, when the short circuit state of the electrode required at the time of actual measurement is abnormal, it is possible for the operator to recognize it by notification to that effect, so it is possible to prevent the actual measurement from continuing with the short circuit abnormality occurring. Is done. As a result, the actual measurement can be performed again by the operator, and it is possible to contribute to obtaining a highly accurate tip voltage. In addition, the occurrence of an unexpected arc due to a short circuit abnormality can be suppressed, which can contribute to the improvement of the working environment.

  According to a second aspect of the present invention, in the welding power source device according to the first aspect, before the actual measurement in the measurement mode, a predetermined voltage application for confirming a short-circuit state of the electrode is performed, and the voltage Pre-measurement determining means for determining whether the output voltage is an abnormal value due to a factor including a short circuit abnormality of the electrode based on application, and the abnormality notification means is determined to be abnormal by the pre-measurement determining means It is the gist of notifying that fact.

  In this invention, before the actual measurement in the measurement mode, the predetermined voltage application for confirming the short-circuit state of the electrode is performed by the pre-measurement determination unit, and the output voltage includes an electrode short-circuit abnormality based on the voltage application. It is determined whether or not the value is an abnormal value. If it is determined that the pre-measurement determining means is abnormal, the abnormality notifying means notifies that there is an abnormality. As a result, before the actual measurement, when the short circuit state of the electrode required at the actual measurement is abnormal, it is possible for the operator to recognize by the notification to that effect, so the actual measurement can be performed with the short circuit abnormality occurring. It is prevented in advance.

  According to a third aspect of the present invention, in the welding power supply device according to the second aspect, the voltage applied to the electrode at the time of the pre-measurement determination by the pre-measurement determination unit is greater than the voltage applied during actual measurement. The gist of this is that it is set to a small voltage value.

  In the present invention, the applied voltage to the electrode at the time of determination before measurement is set to a voltage value smaller than the applied voltage during actual measurement, so it is possible to reliably prevent the occurrence of an unexpected arc due to a short circuit abnormality and further improve the working environment. Can contribute.

Invention of Claim 4 is the welding machine comprised by providing the power supply device for welding of any one of Claims 1-3.
According to the present invention, it is possible to provide a welding machine that can prevent measurement of a resistance value and an inductance value while a short circuit abnormality has occurred.

  According to the present invention, when measuring the resistance value and the inductance value used for the calculation of the electrode tip voltage with the electrode short-circuited, a welding power supply apparatus that can prevent measurement while the short-circuit abnormality occurs, and its A welding machine including a welding power supply device can be provided.

It is a block diagram which shows the power supply device of the arc welder of this embodiment. It is explanatory drawing for demonstrating the change of an inductance value. It is explanatory drawing for demonstrating the calculation method of resistance value and an inductance value. It is a timing diagram used for description of determination of a short circuit state.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows a consumable electrode type arc welding machine 10. In the arc welding machine 10, the wire electrode 12 supported by the torch TH is connected to the plus side output terminal of the welding power source device 11, the welding object M is connected to the minus side output terminal of the power source device 11, and the power source Arc welding is performed by supplying the DC output power generated by the apparatus 11 to the wire electrode 12. At this time, since the wire electrode 12 is consumed during welding, the wire supply device 13 feeds the wire electrode 12 according to the consumption. Output power is supplied to the wire electrode 12 and the welding target M via a power cable 14 connected to the output terminal of the power supply device 11.

  The welding power source device 11 converts three-phase AC input power supplied from a commercial power source into DC output power suitable for arc welding. The AC input power is converted into DC power by a rectifying / smoothing circuit 21 including a diode bridge and a smoothing capacitor, and the converted DC power is converted into high-frequency AC power by an inverter circuit 22. The inverter circuit 22 is configured by a bridge circuit using four switching elements TR such as IGBTs, and PWM control by the control device 31 is performed.

  The high-frequency AC power generated by the inverter circuit 22 is converted to secondary AC power adjusted to a predetermined voltage value by the welding transformer 23. The secondary side AC power of the welding transformer 23 is converted into DC output power suitable for arc welding by a rectifier circuit 24 using a diode and a DC reactor 25.

  A supersaturated reactor having supersaturation characteristics is used for the direct current reactor 25 of the present embodiment. As shown in FIG. 2, the characteristic of the DC reactor 25 is a normal characteristic region A1 in which a high current region that is larger than a predetermined current value Ia including the current value Ip1 is constant at a minimum necessary inductance value La. On the other hand, the low current region where the current value is equal to or less than the predetermined current value Ia is a supersaturation characteristic region A2 in which the inductance value gradually increases linearly as the current value decreases (inductance value Lb at the current value Ip2). In other words, by using the DC reactor 25 having such characteristics, since the inductance value is small in the high current region, the influence on the waveform control for current smoothing is small, and in the low current region, the inductance value is increased to increase the arc. A suitable DC output power is generated over the entire current region so that disconnection is prevented.

  As shown in FIG. 1, the control device 31 performs PWM control on the switching element TR of the inverter circuit 22 to control the DC output power to an appropriate value from time to time. At this time, the control device 31 detects the output current I and the output voltage V from time to time, and performs feedback to the PWM control based on the detected output current I and output voltage V.

  That is, the current sensor 33 is provided on the power supply line of the negative output terminal in the power supply device 11, and the control device 31 outputs the output current I of the power supply device 11 via the current sensor 33 in the processing unit (CPU) 32. Is detected. A voltage sensor 34 is provided between the power supply lines immediately after the rectifier circuit 24, and the control device 31 detects the output voltage V of the power supply device 11 through the voltage sensor 34 in the processing unit 32. The control device 31 calculates the duty of the PWM control based on the output current I and the output voltage V detected at that time by the processing unit 32 and generates a PWM control signal to be output to the inverter circuit 22.

  Here, in the PWM control, it is preferable to use the tip voltage Va of the wire electrode 12 at which an arc is generated as the output voltage V used for the control, but it is difficult to directly detect the tip voltage Va. Therefore, the control device 31 holds in advance a voltage change between the voltage sensor 34 and the electrode 12 in a storage device (not shown), and corrects the voltage change to the output voltage V detected at that time. The tip voltage Va is obtained to perform PWM control using the calculated tip voltage Va.

  By the way, the voltage change between the voltage sensor 34 and the electrode 12 includes the voltage change in the power supply device 11 (voltage change due to the resistance value R1 and the inductance value L1 from the rectifier circuit 24 to the output terminal), the external Voltage variation (voltage variation due to the resistance value R2 and the inductance value L2 from the output terminal to the tip of the electrode 12 via the power cable 14). Since the internal voltage change of the power supply device 11 is not affected by the use state, it can be incorporated in the calculation of the tip voltage Va as a correction term in advance. Since the conditions are different for each user such as the laying state (straight line laying, round laying, and the number of laps), it is greatly affected by the change in the resistance value R2, particularly the inductance value L2.

  Therefore, when the user installs the arc welding machine 10 on the site and puts it in a state of use including the installation of the power cable 14, the internal resistance value R1 and the inductance value L1, and the external resistance value R2 and the inductance value. A resistance value R and an inductance value L obtained by adding up L2 are measured. The measured total resistance value R and total inductance value L are held in the control device 31.

  Note that the power supply device 11 of the present embodiment is provided with a measurement mode for executing processing for measuring the total resistance value R and the total inductance value L, and an operation switch (illustrated) provided in the power supply device 11 is provided. The control device 31 can shift to the measurement mode based on the operation of (omitted). Further, a torch switch provided in the torch TH and an operation remote controller (both not shown) provided in the wire supply device 13 may be used so that the measurement mode can be shifted from a position away from the power supply device 11. Incidentally, at the time of measurement in the measurement mode, the wire electrode 12 needs to be short-circuited with the welding object M, but in this embodiment, the wire electrode 12 is directly short-circuited to the welding object M as shown in FIG. First, the contact tip THa, which is provided at the tip of the torch TH and supplies power to the wire electrode 12, is short-circuited to the welding object M. In this case, a special jig for short circuit may be produced and used.

  The measurement mode will be described in detail. As shown in FIG. 3, first, the inverter circuit 22 is operated to increase the output current I to the current value Ip1. This current value Ip1 is a current value in the normal characteristic region A1 that is constant at the inductance value La in a single DC reactor 25 having supersaturation characteristics. Actually, as shown in FIG. 2, the characteristic is offset depending on the laying state of the power cable 14 and the total inductance value L is constant at the offset value La1, but the normal characteristic region A1 in consideration of the offset is also provided. Set to current value. And the average voltage value Ve in the area hold | maintained with such electric current value Ip1 is measured. Thereby, first, the total resistance value R is calculated by the following equation (a).

R = Ve / Ip1 (a)

Next, the operation of the inverter circuit 22 is stopped, and time measurement is started from the time T0 at this time. At the same time, sampling of the output current I that changes every moment from the time T0 is performed, and the time when the current value ΔIp1 (Ip1 × 36.8%) corresponding to the time constant is reached is defined as T1, A time (time constant) τ1 between times T1 and T0 is obtained. Thereby, the total inductance value La1 (inductance value La in the case of the reactor 25 alone) that changes in the normal characteristic region A1 is calculated by the following equation (b).

La1 = R · τ1 (= Ve · τ1 / Ip1) (b)

Next, the inverter circuit 22 is operated again, and the output current I is adjusted to a predetermined current value Ip2 in the oversaturation characteristic region A2. After the adjustment, the operation of the inverter circuit 22 is stopped again, and time measurement is started from time T2 at this time. At the same time, the sampling of the output current I that changes every moment from the time T2 is performed, and the time when the current value ΔIp2 (Ip2 × 36.8%) that becomes the current attenuation corresponding to the time constant is reached is defined as T3. A time (time constant) τ2 between times T3 and T2 is obtained. Thereby, the total inductance value Lb1 (inductance value Lb for the reactor 25 alone) that changes in the supersaturation characteristic region A2 is calculated by the following equation (c).

Lb1 = R · τ2 = (Ve · τ2 / Ip2) (c)

Next, as shown in FIG. 2, the calculated total inductance value La1 of the normal characteristic region A1 and the total inductance value Lb1 of the supersaturated characteristic region A2 are linearly complemented, so that the total inductance value L is a function L (I) of the current I. As obtained. The function L (I) of the total inductance value L obtained in this way and the total resistance value R obtained previously are held in the control device 31. This completes the measurement mode.

And the control apparatus 31 is calculating the front-end | tip voltage Va by following Formula (d) from the output current I and the output voltage V at the time of welding operation.

Va = V−L (I) · dI / dt−RI (d)

Incidentally, in terms of specific numerical values, when the inverter circuit 22 is turned on, the current value Ip1 = 400 [A] of the output current I is output for 10 [ms], and then the inverter circuit 22 is turned off. If the average voltage value Ve during this time is 4 [V], from the above equation (a),

R = Ve / Ip1 = 4/400 = 0.01 [Ω]

And the total resistance value R is calculated.

Next, the current value ΔIp1 at which the current value Ip1 is a current attenuation amount corresponding to the time constant τ1 is

ΔIp1 = 400 × 0.368 = 147 [A]

If the time constant τ1 for reaching the output current I from 400 [A] to 147 [A] after turning off the inverter circuit 22 is 3 [ms], the above equation (b)

La1 = R · τ1 = 0.01 × 3 = 0.03 [mH]

In the normal characteristic region A1, the total inductance value La1 including the single inductance value La of the DC reactor 25 is calculated. The current value Ip1 described above needs to be estimated from the specifications of the DC reactor 25 used in advance and set to a value that does not reach the oversaturation characteristic region A2.

Next, the inverter circuit 22 is turned on again, and the output current I is output for 10 [ms] as a current value Ip2 = 20 [A] corresponding to the minimum current of the arc welding machine 10 in the supersaturation characteristic region A2, for example. Then, the inverter circuit 22 is turned off. The current value ΔIp2 at which the current value Ip2 is a current attenuation amount corresponding to the time constant τ2 is

ΔIp2 = 20 × 0.368 = 7 [A]

If the time constant τ2 at which the output current I reaches 7 [A] from 20 [A] after turning off the inverter circuit 22 is 10 [ms], the above equation (c)

Lb1 = R · τ2 = 0.01 × 10 = 0.1 [mH]

In the supersaturation characteristic region A2, the total inductance value Lb1 including the single inductance value Lb of the DC reactor 25 is calculated.

  Then, by performing linear interpolation of La1 = 0.03 [mH] and Lb1 = 0.1 [mH], a function L (I) of the total inductance value L is obtained, and the previously obtained total resistance value R Thus, the tip voltage Va at that time can be calculated from the above equation (d). In addition, the specific numerical value quoted above is an example, and is not limited to this.

  Since the tip voltage Va is appropriately calculated even in the welding power supply device 11 of the present embodiment using the DC reactor 25 having the supersaturation characteristic in this way, an inverter based on the tip voltage Va that is appropriately calculated. The occasional control of the circuit 22 is more appropriately performed. Therefore, the synergistic effect with the use of the reactor 25 having the supersaturation characteristic enables generation of more appropriate DC output power for arc welding over the entire current region.

  By the way, before the actual measurement in the measurement mode, it is determined whether the electrode 12 (contact chip THa) is in a sufficiently short-circuited state (determination before measurement). Specifically, as shown in FIG. 4, for example, a voltage of about 15 [V] is applied to the electrode 12 (contact chip THa) before the actual measurement performed by increasing the output current I to the current value Ip1. Application is performed. Hereinafter, the output voltage V used above is divided between the actual output side and the detection side, the output voltage on the actual output side is “Vs”, and the output voltage on the detection side is “Vm”.

  When the short circuit state of the electrode 12 (contact chip THa) is normal based on the application of the output voltage Vs of 15 [V] at the time of determination before measurement, the output voltage detected by the processing unit 32 of the control device 31 Vm is a slight voltage value near 0 [V]. Therefore, since the detected output voltage Vm is lower than the threshold value for determining the short circuit abnormality, the processing unit 32 determines that the short circuit is possible for actual measurement. On the other hand, when a short circuit abnormality has occurred, the voltage value of the detected output voltage Vm increases. When the processing unit 32 becomes higher than the threshold value for determining the short circuit abnormality, the processing unit 32 determines that the short circuit abnormality state in which the next actual measurement cannot be suitably performed. Then, the processing unit 32 activates the abnormality notification device 36 to notify the operator of the abnormality.

  The abnormality notification device 36 is configured by a device that performs notification by sound generation, such as notification using a display provided in the power supply device 11, the torch TH, the wire supply device 13, etc., or the operation sound of a buzzer or relay. Further, when the arc welding machine 10 is used for welding while discharging an inert gas from the tip of the torch TH, the previous abnormality notification can also be performed by a gas emission sound. Then, the worker is notified of the abnormality, the electrode 12 (contact tip THa) is reliably short-circuited, and the measurement from the determination before measurement is performed again.

  Next, since the short circuit state of the electrode 12 (contact chip THa) may be abnormal during the actual measurement, the processing unit 32 of the control device 31 detects the abnormal voltage of the detected output voltage Vm. Is going. When detecting that an abnormal voltage resulting from the short circuit abnormality has occurred, the processing unit 32 operates the abnormality notification device 36 in the same manner as described above to notify the operator of the abnormality. Similarly, the operator is notified of the abnormality, and the electrode 12 (contact tip THa) is reliably short-circuited, and the measurement from the pre-measurement determination is performed again.

  Further, it is conceivable that the acquired total resistance value R and total inductance value L can be abnormal values even if the measurement ends normally without occurrence of short circuit abnormality of the electrode 12 (contact chip THa). For example, when the power cable 14 laid between the power supply device 11 and the torch TH is not compatible with the cross-sectional area, the cable length, or the like, or is in an abnormal winding state as a compatible product. Then, the measured value can be an abnormal value. Based on this, the storage device 35 included in the control device 31 of the present embodiment has a resistance value ○ [Ω] and an inductance value Δ [ The appropriate range with [μH] is associated and stored in a database (DB).

  And the process part 32 determines whether the total resistance value R and the total inductance value L which were actually measured are in the appropriate range from the appropriate range of the resistance value and inductance value of the cable 14 currently used. If it is within the appropriate range, the total resistance value R and the total inductance value L are updated, that is, the data of the total resistance value R and the total inductance value L currently held as the control device 31 is updated, and the subsequent control is performed. Used. On the other hand, when it is determined that the measured total resistance value R or total inductance value L is outside the appropriate range (abnormal value), the data of the total resistance value R or total inductance value L currently held as the control device 31 is obtained. Abnormality notification by the abnormality notification device 36 is performed without updating. Upon receiving the abnormality notification, the operator can confirm the measurement state, confirm the power cable 14 currently used, confirm the laying state, and the like.

Next, characteristic effects of the present embodiment will be described.
(1) Actual measurement of each measured value in the measurement mode for measuring the total resistance value R and the total inductance value L (function L (I) in the present embodiment) up to the tip of the electrode 12 for calculating the tip voltage Va. It is determined whether or not the detected output voltage V (Vm) is an abnormal value due to a factor including a short circuit abnormality of the electrode 12. If it is determined that there is an abnormality, the abnormality notification device 36 notifies the abnormality. Thereby, when the short-circuit state of the electrode 12 required at the time of actual measurement is abnormal, it becomes possible for the operator to recognize by the notification to that effect, so that the actual measurement is continued with the short-circuit abnormality occurring. Can be prevented. As a result, the actual measurement can be performed again by the operator, and it is possible to contribute to obtaining the accurate tip voltage Va. In addition, the occurrence of an unexpected arc due to a short circuit abnormality can be suppressed, which can contribute to the improvement of the worker's working environment.

  (2) Before actual measurement in the measurement mode, a predetermined voltage application (about 15 [V]) for confirming the short-circuit state of the electrode 12 is performed, and the output voltage V (Vm) is applied to the electrode based on the voltage application. It is determined whether the value is an abnormal value due to a factor including 12 short-circuit abnormalities. If it is determined that there is an abnormality, the abnormality notification device 36 notifies the abnormality. As a result, when the short circuit state of the electrode 12 required at the actual measurement is abnormal before the actual measurement, it is possible for the operator to recognize by the notification to that effect, so the actual measurement is performed with the short circuit abnormality occurring. Can be prevented in advance.

  (3) The applied voltage to the electrode 12 at the time of determination before measurement is, for example, 15 [V] in the present embodiment, and is set to a voltage value sufficiently smaller than the applied voltage during actual measurement. Therefore, it is possible to reliably prevent the occurrence of an unexpected arc due to a short circuit abnormality and contribute to further improving the working environment.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the applied voltage to the electrode 12 is set to about 15 [V] at the time of determination before measurement, but the voltage value is an example and may be changed as appropriate. In this case, it is preferable to set the voltage value sufficiently smaller than the applied voltage during actual measurement.

  In the above embodiment, the determination of the short-circuit abnormality of the electrode 12 is performed both during and before the actual measurement of each measured value of the resistance value R and the inductance value L, but at least during the actual measurement, It may be omitted before the measurement.

The abnormality notification device 36 described in the above embodiment is an example, and may be changed as appropriate.
In the above embodiment, the database (DB) related to the various cables 14 is stored in the storage device 35 and compared with each measurement value, but this may be omitted.

  In the above embodiment, the DC reactor 25 having the supersaturation characteristic is used. However, a general reactor having a linear characteristic in which the current value and the inductance value change constant may be used. Incidentally, if such a reactor is used, the inductance value can be obtained by measuring the current attenuation once (the function need not be obtained), and the tip voltage Va can be easily calculated.

10 Arc welding machine (welding machine)
11 Welding power supply device 12 Wire electrode (electrode)
22 Inverter circuit 23 Welding transformer 24 Rectifier circuit (DC conversion means)
25 DC reactor (DC conversion means)
31 Control device (control means, tip voltage calculation means, resistance value calculation means, inductance value calculation means, short circuit abnormality determination means, pre-measurement determination means, abnormality notification means)
33 Current sensor (detection means)
34 Voltage sensor (detection means)
36 Abnormality notification device (abnormality notification means)
M Welding object I Output current Ip1 Current value Ip2 Current value V Output voltage Vs Output voltage (actual output)
Vm Output voltage (detection)
Va tip voltage R Total resistance L Total inductance L (I) Function

Claims (4)

An inverter circuit for converting DC power into high-frequency AC power, a welding transformer for adjusting the voltage of the converted AC power, and DC conversion means for generating DC output power suitable for welding from the secondary AC power of the welding transformer; And generating an arc for welding with the welding target based on the supply of the generated output power to the electrode, and an output current and an output voltage detected by the detection means in the apparatus. A welding power supply device further comprising a control means for calculating the tip voltage of the electrode based on the control voltage and controlling the inverter circuit based on the calculated tip voltage,
The total resistance value on the path to the electrode tip is calculated based on the voltage value of the output voltage when the electrode is short-circuited and the output current generated by the operation of the inverter circuit is a predetermined current value. And a resistance value calculating means for performing a short circuit on the electrode, and on the path to the tip of the electrode based on a current attenuation amount when the output current generated by the operation of the inverter circuit is set to a predetermined current value. The total resistance on the path to the tip of the electrode with respect to the voltage value of the output voltage detected by the detection means, having a measurement mode for executing processing including an inductance value calculation means for calculating a total inductance value A tip voltage calculating means for calculating the tip voltage by correcting a voltage change applied to the value and the total inductance value;
During actual measurement in the measurement mode, the short-circuit abnormality determining means for determining whether the output voltage detected by the detection means is an abnormal value due to a factor including a short-circuit abnormality of the electrode;
A welding power supply apparatus comprising: an abnormality notifying means for notifying that the abnormality is determined by the short circuit abnormality determining means. In the welding power supply device according to claim 1,
Prior to actual measurement in the measurement mode, a predetermined voltage application for confirming the short-circuit state of the electrode is performed, and based on the voltage application, whether the output voltage is an abnormal value due to a factor including a short-circuit abnormality of the electrode A pre-measurement judging means for judging whether
The welding power supply device according to claim 1, wherein the abnormality notifying unit notifies that when the pre-measurement determining unit determines that an abnormality has occurred. The welding power supply device according to claim 2,
The welding power supply apparatus, wherein a voltage applied to the electrode during the pre-measurement determination by the pre-measurement determination unit is set to a voltage value smaller than a voltage applied during actual measurement.   A welding machine comprising the welding power supply device according to claim 1.

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