WO2018220933A1 - Power supply device for arc processing and method for controlling power supply device for arc processing - Google Patents

Power supply device for arc processing and method for controlling power supply device for arc processing Download PDF

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Publication number
WO2018220933A1
WO2018220933A1 PCT/JP2018/008926 JP2018008926W WO2018220933A1 WO 2018220933 A1 WO2018220933 A1 WO 2018220933A1 JP 2018008926 W JP2018008926 W JP 2018008926W WO 2018220933 A1 WO2018220933 A1 WO 2018220933A1
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Prior art keywords
circuit
welding
inverter
output current
output
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PCT/JP2018/008926
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French (fr)
Japanese (ja)
Inventor
善行 濱野
芳行 田畑
徹也 森川
司 三澤
宏太 堀江
Original Assignee
パナソニックＩｐマネジメント株式会社
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Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Priority to JP2019521962A priority Critical patent/JP6982744B2/en
Priority to CN201880035401.7A priority patent/CN110679076B/en
Publication of WO2018220933A1 publication Critical patent/WO2018220933A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/493—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/06—Arrangements or circuits for starting the arc, e.g. by generating ignition voltage, or for stabilising the arc
    • B23K9/073—Stabilising the arc
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

  • This disclosure relates to a technique for providing a plurality of inverter circuits built in an arc machining power supply device in parallel and operating in parallel.
  • a plurality of inverter circuits are provided in parallel to perform parallel operation.
  • the arc machining power supply apparatus provided with a plurality of inverter circuits as described above, especially when the output current is small, it is better to stop some inverter circuits than to drive all inverter circuits. Weldability may be improved.
  • Patent Document 1 In a conventional arc machining power supply device in which a plurality of inverter circuits are provided in parallel, a method is disclosed in which a certain inverter circuit is stopped by detecting a missing tooth in the pulse waveform of the output control signal of the inverter circuit ( Patent Document 1).
  • the power consumption of the entire arc machining power supply device may increase by stopping a certain inverter circuit.
  • the present disclosure provides a technique for controlling the power consumption of the arc machining power supply apparatus to be small in the arc machining power supply apparatus in which a plurality of inverter circuits are provided in parallel.
  • An arc machining power supply apparatus is an arc machining power supply apparatus that performs short-circuit welding or pulse welding on an object to be welded, and is a first 1 that rectifies commercial AC power and outputs a DC voltage.
  • a circuit a first main transformer that converts the output of the first inverter circuit into a high-frequency AC voltage suitable for arc machining, a first secondary rectifier circuit that rectifies the output of the first main transformer, Smoothed by a second primary rectifier circuit that rectifies commercial AC power and outputs a DC voltage, a second smoothing capacitor that smoothes the DC voltage output from the second primary rectifier circuit, and a second smoothing capacitor
  • High frequency AC A second inverter circuit for converting to a voltage; a second main transformer for converting the output of the second inverter circuit to a high-frequency AC voltage suitable for arc machining; and a second for rectifying the output of the second main transformer.
  • An output current detection circuit for detecting the output current; an output current setting circuit for setting a preset value related to a predetermined output current; and a first number that stores in advance a minimum number of inverter circuits that require driving corresponding to the output current Comparing the storage circuit, the set value related to the output current set by the output current setting circuit and the minimum number of inverter circuits that need to be driven corresponding to the output current stored in the first storage circuit, Drive corresponding to the setting Comparison circuit for obtaining the minimum number of necessary inverter circuits, power consumption with respect to temperature, which is the relationship between the temperature of the switching elements constituting the inverter circuit, the inverter output current per inverter circuit to be driven, and the power consumption of the inverter circuit
  • a second storage circuit for storing the relationship in advance,
  • a control method for a power supply device for arc machining in which a plurality of inverter circuits are provided in parallel, and short-circuit welding having a welding start period, a main welding period, and a welding end period is performed on a workpiece.
  • the measured value of the temperature of the switching element constituting the inverter circuit and the time average of the output current output to the work piece The power consumption in the combination of the operation of each inverter circuit is calculated from the average output current, and the driving and stopping of the plurality of inverter circuits are selected so that the total power consumption in each of the plurality of inverter circuits is minimized. To do.
  • a method for controlling a power supply device for arc machining in which a plurality of inverter circuits are provided in parallel and a pulse welding having a welding start period, a main welding period, and a welding end period with respect to an object
  • each inverter circuit is based on the measured value of the temperature of the switching element constituting the inverter circuit and the base current and peak current of the pulse welding.
  • the power consumption in the combination of operations is calculated, and driving and stopping of each of the plurality of inverter circuits are selected so that the total power consumption in the plurality of inverter circuits is minimized.
  • the arc machining power supply device is a large current compatible arc machining power supply device including a plurality of power supply units connected in parallel.
  • Each power supply unit includes a primary rectifier circuit, a smoothing capacitor, an inverter circuit, a main transformer, and a secondary rectifier circuit.
  • the arc machining power supply device measures the temperature of the switching elements constituting each inverter circuit, and based on them, determines whether to drive or stop each inverter circuit so that the power consumption in each inverter circuit is minimized. Therefore, the power consumption of the arc machining power supply device can be reduced.
  • FIG. 1 is an electrical connection diagram of an arc machining power supply device in which two power supply units are provided in parallel.
  • FIG. 2 shows an example of information stored in the first storage circuit in the arc machining power supply apparatus in which two power supply units are provided in parallel, that is, the minimum number of inverter circuits that need to be driven corresponding to the output current. It is a figure which shows an example of the relationship of a number.
  • FIG. 3A shows an example of information stored in the second storage circuit in the arc machining power supply device in which two power supply units are provided in parallel, that is, an example of the relationship of power consumption with respect to temperature.
  • FIG. 3B is a diagram illustrating another example of the relationship of power consumption with respect to temperature.
  • FIG. 4 is a diagram illustrating an example of a calculation result of the calculation circuit in the arc machining power supply device in which two power supply units are provided in parallel.
  • FIG. 5 is a diagram illustrating an example of an output current waveform and an output voltage waveform during short-circuit welding.
  • FIG. 6A is a diagram illustrating the power consumption of the inverter circuit in a normal temperature region with respect to a combination of driving and stopping of each inverter circuit.
  • FIG. 6B is a diagram illustrating the power consumption of the inverter circuit in a high temperature region with respect to a combination of driving and stopping of each inverter circuit.
  • FIG. 7 is a diagram illustrating a calculation result of the calculation circuit.
  • FIG. 8 is a diagram illustrating an example of the relationship between the output current and output voltage during short-circuit welding and the number of inverter circuits to be driven.
  • FIG. 9 is a diagram illustrating an example of the relationship between the output current and output voltage during short-circuit welding and the number of inverter circuits to be driven.
  • FIG. 10 is a diagram illustrating an example of an output current waveform and an output voltage waveform during pulse welding.
  • FIG. 11 is a diagram illustrating an example of the relationship between the output current and the output voltage during pulse welding and the number of inverter circuits to be driven.
  • FIG. 1 shows an arc machining power supply device in which two power supply units formed of a primary rectifier circuit, a smoothing capacitor, an inverter circuit, a main transformer, and a secondary rectifier circuit are provided in parallel.
  • a DC power supply circuit is formed by the first primary rectifier circuit DR11 that rectifies AC power from the commercial AC power supply AC and outputs a DC voltage, and the first smoothing capacitor C1 that smoothes the DC voltage.
  • the second primary rectifier circuit DR12 and the second smoothing capacitor C2 are provided in parallel with the first primary rectifier circuit DR11, and smooth the DC voltage with the first primary rectifier circuit DR11, respectively. The same operation as that of the first smoothing capacitor C1 is performed.
  • the first inverter circuit INV1 is formed by a switching element such as an IGBT or a MOSFET.
  • the first inverter circuit INV1 converts the DC voltage output by the first primary rectifier circuit DR11 into a high-frequency AC voltage and outputs it.
  • the second inverter circuit INV2 converts the DC voltage output by the second primary rectifier circuit DR12 into a high-frequency AC voltage and outputs it.
  • the first main transformer MTR1 converts the high-frequency AC voltage output from the first inverter circuit INV1 into a high-frequency AC voltage suitable for arc machining.
  • the first secondary rectifier circuit DR21 rectifies the output of the first main transformer MTR1 and outputs a direct current.
  • the second main transformer MTR2 converts the high-frequency AC voltage output from the second inverter circuit INV2 into a high-frequency AC voltage suitable for arc machining.
  • the second secondary rectifier circuit DR22 rectifies the output of the second main transformer MTR2 and outputs a direct current.
  • the DC reactor DCL smoothes a DC current that is a combination of the DC current output from the first secondary rectifier circuit DR21 and the DC current output from the second secondary rectifier circuit DR22.
  • An electric wire that can be electrically connected by an operator is attached between the output terminal OT and the torch TH and between the output terminal OT and the workpiece M.
  • the output terminal OT supplies a direct current smoothed by the direct current reactor DCL between the torch TH and the workpiece M as a welding current.
  • the output current detection circuit CT detects an output current as a welding current, and outputs an output current detection signal Io indicating the detected output current.
  • the output current is a direct current obtained by adding the direct current output from the first secondary rectifier circuit DR21 and the direct current output from the second secondary rectifier circuit DR22.
  • the output current setting circuit IS outputs a set value related to the output current that is adjusted in advance by the operator as the output current setting signal Is.
  • the first storage circuit MC1 stores in advance the relationship between the minimum number of inverter circuits that need to be driven at the minimum with respect to the output current.
  • the inverter circuits are the first inverter circuit INV1 and the second inverter circuit INV2.
  • the first memory circuit MC1 outputs this stored relationship as the first memory signal Mc1.
  • the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven corresponding to the output current.
  • the output current has a current value less than the output current threshold Ith, at least one inverter circuit needs to be driven.
  • the output current has a current value equal to or greater than the output current threshold Ith, it is necessary to drive at least two inverter circuits.
  • the comparison circuit CC shown in FIG. 1 compares the output current setting signal Is and the first storage signal Mc1, and outputs the minimum number of inverter circuits that need to be driven as the comparison signal Cc.
  • the second storage circuit MC2 stores the relationship of the power consumption of the inverter circuit with respect to the temperature, and outputs this relationship as the second storage signal Mc2. More specifically, this relationship is the relationship between the inverter output current per inverter circuit to be driven and the power consumption of the inverter circuit with respect to the temperature of the switching elements constituting the inverter circuit.
  • the second memory circuit MC2 stores the relationship between the inverter output current per inverter circuit to be driven with respect to the temperature and the power consumption of the inverter circuit as shown in FIG. 3A. As is apparent from the figure, if the output current per one inverter circuit to be driven increases, the power consumption of the inverter circuit tends to increase.
  • the slope of power consumption with respect to the inverter output current per inverter circuit to be driven increases as compared with a normal temperature of 5 to 35 ° C.
  • the slope of power consumption with respect to the inverter output current per inverter circuit to be driven may decrease as compared with normal temperature.
  • the relationship of the power consumption of the inverter circuit with respect to the temperature stored in the second memory circuit MC2 is determined from the specifications of the switching elements (IGBT and MOSFET) constituting the first inverter circuit INV1 and the second inverter circuit INV2. it can.
  • the first measured temperature value T1 shown in FIG. 1 is a measured temperature value of the switching elements constituting the first inverter circuit INV1.
  • the second temperature measurement value T2 is a temperature measurement value of the switching element that constitutes the second inverter circuit INV2.
  • the temperature of these switching elements is measured by a thermistor (not shown).
  • the arithmetic circuit OC calculates the total power consumption of all inverter circuits for the combination of driving and stopping of each inverter circuit. This total power consumption is obtained based on the first temperature measurement value T1, the second temperature measurement value T2, and the second storage signal Mc2.
  • the arithmetic circuit OC outputs the calculation result as the calculation signal Oc.
  • the calculation result of the power consumption in the combination of each inverter circuit by the arithmetic circuit OC is as shown in FIG. There are three combinations of driving and stopping of the first inverter circuit INV1 and the second inverter circuit INV2 (except when both are stopped).
  • the arithmetic circuit OC calculates power consumption values W21, W22, and W43 (W31 + W32) that are the total power consumption Ww3 in each case.
  • the power consumption value W21 is the total power consumption when the first inverter circuit INV1 is driven and the second inverter circuit INV2 is stopped, that is, when only one first inverter circuit INV1 is driven. This is the total power consumption value.
  • the power consumption value W22 is the total power consumption when the first inverter circuit INV1 is stopped and the second inverter circuit INV2 is driven, that is, when only one second inverter circuit INV2 is driven. This is the total power consumption value.
  • the power consumption value W43 is a value of the total power consumption when the two inverter circuits are driven and the first inverter circuit INV1 and the second inverter circuit INV2 are driven together, that is, the first inverter circuit. This is the sum of the power consumption value W31 of INV1 and the power consumption value W32 of the second inverter circuit INV2.
  • the selection circuit SC shown in FIG. 1 selects the combination that minimizes the total power consumption of the first inverter circuit INV1 and the second inverter circuit INV2 among the combinations of the minimum number of inverter circuits that need to be driven. To do. This selection result is obtained based on the comparison signal Cc and the calculation signal Oc.
  • the selection circuit SC outputs a selection result related to driving or stopping of each inverter circuit as a selection signal Sc.
  • the output control circuit OCC controls the output of the inverter circuit whose drive is selected by the selection signal Sc so that the output current detection signal Io becomes equal to the output current setting signal Is.
  • the output control circuit OCC further controls the output of the inverter circuit whose stop is selected by the selection signal Sc to be zero.
  • the output control circuit OCC outputs a first output control signal Occ1 for controlling the output of the first inverter circuit INV1 and a second output control signal Occ2 for controlling the output of the second inverter circuit INV2. .
  • the first inverter drive circuit SD1 outputs a first inverter drive signal Sd1 for driving the first inverter circuit INV1 according to the first output control signal Occ1.
  • the second inverter drive circuit SD2 outputs a second inverter drive signal Sd2 for driving the second inverter circuit INV2 according to the second output control signal Occ2.
  • the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current shown in FIG.
  • the second memory circuit MC2 stores the relationship between the temperature of the switching element constituting the inverter circuit shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit.
  • the short-circuit welding includes a welding start period Th, a main welding period Tw, and a welding end period Te.
  • the main welding period is a period in which the short circuit period Ts in the short circuit state and the arc period Ta in the arc state are repeated.
  • the first inverter circuit INV1 and the second inverter circuit INV2 are configured by the same switching element.
  • the same switching element has the same model, in other words, a switching element having the same performance.
  • FIG. 5 shows an output current waveform and an output voltage waveform during short-circuit welding.
  • the main welding period Tw is a period during which welding is performed by moving the torch TH in accordance with a location (welding line) where the workpiece M is desired to be welded.
  • the average output current Iw is a time average of the output current supplied between the welding wire and the workpiece M in the main welding period Tw, in other words, output to the workpiece M.
  • the average output current Iw corresponds to a set current as a set value of the output current in the main welding period Tw.
  • the welding start period Th is a period during which a process for making it easy to start welding by outputting a start current Ih higher than the average output current Iw of the main welding period Tw for a certain period of time.
  • the welding end period Te is a period during which a terminal current Ie lower than the average output current Iw of the main welding period Tw is output for a certain period of time to prevent the welding wire and the workpiece M from sticking to each other. Basically, an operator adjusts the average output current Iw in the main welding period Tw and performs welding suitable for the workpiece M.
  • the main welding period Tw of the short circuit welding includes the short circuit period Ts and the arc period Ta.
  • the short circuit period Ts is a short circuit period in which the welding wire and the workpiece M are in electrical contact (short circuit).
  • the arc period Ta is an arc state period in which a short circuit is opened and an arc is generated. As shown in FIG. 5, the output voltage is low in the short circuit period Ts. On the other hand, in the arc period Ta, the output voltage increases and the output current decreases from a high current value.
  • the output power in the main welding period in the short-circuit welding is constant to some extent although there is some variation if the set value of the average output current Iw is constant.
  • the value of the average output current Iw set by the operator can be handled as the set value of the output current setting signal Is.
  • the comparison signal Cc indicates driving of two inverter circuits.
  • the comparison signal Cc indicates driving of at least one inverter circuit. In this case, the minimum number of inverter circuits driven by the first temperature measurement value T1 and the second temperature measurement value T2 changes.
  • FIG. 3A shows the characteristics of the switching element of the inverter circuit in which the slope of increase in power consumption is smaller in the normal temperature region than in the high temperature region. If the output current per inverter circuit increases, the power consumption of the inverter circuit tends to increase. In addition, the slope of increase in power consumption is smaller in the normal temperature region than in the high temperature region. In the normal temperature region, even if the output current per one inverter circuit to be driven increases, the rate of increase in power consumption is small.
  • the high temperature region is a temperature that is higher than the normal temperature region and that does not break the switching elements of the inverter circuit, and is, for example, a temperature of 80 to 90 ° C.
  • the normal temperature region is, for example, a temperature of 5 to 35 ° C.
  • the first temperature measurement value T1 and the second temperature measurement value T2 are substantially the same before the start of welding in a room temperature region where the inverter circuit of the arc machining power supply device is sufficiently cooled.
  • the relationship between the inverter output current and the power consumption of the inverter circuit is, for example, as shown in FIG. 6A. Since the temperature of the inverter circuit is in the normal temperature range, the inclination of the increase in power consumption of the inverter circuit with respect to the increase in inverter output current per inverter circuit to be driven is small.
  • the arithmetic circuit OC calculates the total power consumption Ww3 for each combination of driving and stopping of the first inverter circuit INV1 and the second inverter circuit INV2. Specifically, the arithmetic circuit OC calculates the power consumption values Ww11, Ww12, and Ww33 (Ww21 + Ww22) as the total power consumption Ww3.
  • the inverter output current when driving either one of the first inverter circuit INV1 or the second inverter circuit INV2 and supplying the average output current Iw to the output terminal OT is defined as an inverter output current I1. Further, the inverter output current per inverter circuit when the two inverter circuits of the first inverter circuit INV1 and the second inverter circuit INV2 are driven together to supply the average output current Iw to the output terminal OT is obtained. It is assumed that the inverter output current I2. Here, there is a relationship that the inverter output current I1 is larger than the inverter output current I2. When driving two inverter circuits together, the output of each inverter circuit is the same. In other words, the inverter output current I1 has a relationship of about twice the inverter output current I2.
  • the power consumption value Ww11 is the total power consumption when the first inverter circuit INV1 is driven and the second inverter circuit INV2 is stopped, that is, the total when only one first inverter circuit INV1 is driven. This is the power consumption value.
  • the power consumption value Ww12 is the total power consumption when the first inverter circuit INV1 is stopped and the second inverter circuit INV2 is driven, that is, when only one second inverter circuit INV2 is driven. Is the value of the total power consumption.
  • the inverter output current per inverter circuit when driving with the power consumption value Ww11 and the power consumption value Ww12 is the inverter output current I1.
  • the power consumption value Ww33 is a power consumption value that is the sum of the power consumption values of the inverter circuits when both of the inverter circuits are driven. That is, the consumption of the sum of the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2 when both the first inverter circuit INV1 and the second inverter circuit INV2 are driven. This is the power value.
  • the inverter output current per inverter circuit when driving with the power consumption value Ww21 and the power consumption value Ww22 is the inverter output current I2.
  • the power consumption value Ww11 of the first inverter circuit INV1 is the power consumption value of the first inverter circuit INV1 when the current of the average output current Iw is supplied to the output terminal OT only by the first inverter circuit INV1.
  • the power consumption value Ww12 of the second inverter circuit INV2 is the power consumption value of the second inverter circuit INV2 when the current of the average output current Iw is supplied to the output terminal OT only by the second inverter circuit INV2. Note that, under the above-described conditions, the power consumption value Ww11 of the first inverter circuit INV1 and the power consumption value Ww12 of the second inverter circuit INV2 are substantially equal.
  • the inverter output current I2 is an inverter output current per inverter circuit when the two inverter circuits are driven together to supply the average output current Iw to the output terminal OT.
  • the power consumption value Ww21 of the first inverter circuit INV1 is the same as that when the average output current Iw is supplied to the output terminal OT by two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. 1 is a value of power consumption of one inverter circuit INV1.
  • the power consumption value Ww22 of the second inverter circuit INV2 is obtained when the current of the average output current Iw is supplied to the output terminal OT by the two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. This is the power consumption value of the second inverter circuit INV2. Note that, under the above-described conditions, the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2 are substantially equal.
  • the power consumption value Ww33 is the sum of the two inverter circuits when the current of the average output current Iw is supplied to the output terminal OT by the two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. Power consumption. The value is the sum of the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2.
  • the total power consumption Ww3 of the calculation result of the calculation circuit OC for the combination of driving and stopping of each inverter circuit is as shown in FIG.
  • the power consumption of the inverter circuit in the normal temperature region where the temperature of the switching element is low is as shown in FIG. 6A.
  • a combination of operation of the inverter circuit that reduces the power consumption of the inverter circuit during short-circuit welding is as follows.
  • the power consumption value Ww33 is larger than the power consumption value Ww11 and larger than the power consumption value Ww12.
  • the selection circuit SC selects one inverter circuit in the room temperature region so that the power consumption of the arc machining power supply device is reduced, and the selection signal Sc for supplying the average output current Iw to the output terminal OT. Is output.
  • the first temperature measurement value T1 and the second temperature measurement value T2 are substantially equal. Therefore, when any one inverter circuit is driven alone, the power consumption value Ww11 of the first inverter circuit INV1 and the power consumption value Ww12 of the second inverter circuit INV2 are substantially equal. However, the selection signal Sc is actually output so as to drive the smaller inverter circuit.
  • the relationship between the inverter output current and output voltage during short-circuit welding and the number of inverter circuits to be driven is as shown in FIG.
  • Tw and the welding end period Te one inverter circuit is driven.
  • the welding start period Th the inverter output current becomes larger than the output current threshold value Ith, so that two inverter circuits are driven.
  • the temperature of the switching elements constituting the first inverter circuit INV1 and the second inverter circuit INV2 rises in the same manner, and becomes a high temperature region.
  • the temperature of the switching element rises and becomes a high temperature region, the increasing slope of power consumption with respect to the output current per driven inverter circuit increases, in other words, the increase rate increases.
  • the temperature of the switching element of the inverter circuit becomes a high temperature region, and the relationship between the inverter output current per inverter circuit to be driven and the power consumption of the inverter circuit is higher than that in the normal temperature region as shown in FIG. 3A.
  • the increase slope of power consumption becomes larger in the region.
  • the relationship between the inverter output current of each inverter circuit in the high temperature region and the power consumption of the inverter circuit is as shown in FIG. 6B.
  • the power consumption value when one of the first inverter circuit INV1 and the second inverter circuit INV2 is driven is the power consumption value (Ww11, Ww12).
  • the power consumption value that is the sum of the power consumption values (Ww21, Ww22) when the two inverter circuits are both driven is defined as a power consumption value Ww33.
  • the increase slope of the power consumption of the inverter circuit with respect to the inverter output current per one inverter circuit to be driven is larger than the relationship in the normal temperature region shown in FIG. 6A.
  • the total power consumption Ww3 of the calculation result of the calculation circuit OC for the combination of driving and stopping of each inverter circuit is as shown in FIG.
  • the inverter circuit combination itself does not change from the normal temperature region before the temperature rises.
  • the power consumption of the inverter circuit in the high temperature region where the temperature of the switching element is high is in the relationship shown in FIG. 6B, for example, the following combinations of operation of the inverter circuit that reduce the power consumption of the inverter circuit during short-circuit welding It becomes like.
  • the power consumption value Ww33 is smaller than the power consumption value Ww11 or the power consumption value Ww12.
  • the selection circuit SC outputs the selection signal Sc for driving the two inverter circuits together and supplying the average output current Iw to the output terminal OT so that the power consumption of the arc machining power supply device is reduced. To do.
  • the arc machining power supply device of the present embodiment includes a plurality of inverter circuits (INV1, INV2) provided in parallel, and performs short-circuit welding on the workpiece M.
  • the short-circuit welding has a welding start period Th, a main welding period Tw, and a welding end period Te.
  • the arc machining power supply apparatus outputs the measured temperature values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2) and the workpiece M to be welded.
  • the arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits (INV1, INV2), is minimized.
  • Embodiment 2 Next, Embodiment 2 of the present disclosure will be described with reference to FIGS. 1 to 3A and FIGS. 10 to 11.
  • the configuration of the arc machining power supply device of the second embodiment is the same as that of the first embodiment.
  • the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the inverter output current shown in FIG.
  • the second memory circuit MC2 stores the relationship between the temperature of the switching elements constituting the inverter circuit shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit.
  • the first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation of pulse welding will be described with reference to FIGS.
  • Pulse welding includes a main welding period in which a base period Tb and a peak period Tp are repeated.
  • the arc machining power supply device outputs a base current Ib having a low output current value in the base period Tb, and outputs a peak current Ip having a high output current value in the peak period Tp.
  • FIG. 10 shows an output current waveform and an output voltage waveform during pulse welding.
  • the output current waveform and the output voltage waveform at the time of short-circuit welding shown in FIG. 5 having the same reference sign represent the same meaning, and therefore description thereof will be omitted, and only the parts having different reference numerals will be described.
  • a base period Tb with a low output current value and a peak period Tp with a high output current value regularly and alternately exist in the main welding period Tw.
  • the base current Ib represents the output current value in the base period Tb
  • the peak current Ip represents the output current value in the peak period Tp.
  • the arc machining power supply apparatus performs a certain calculation based on the average output current Iw set by the operator, and determines the base current Ib and the peak current Ip.
  • the operator can directly adjust the base current Ib and the peak current Ip.
  • Pulse welding has less contact (short circuit) between the welding wire and the workpiece M than short circuit welding.
  • both the output current and the output voltage are low, and in the peak period Tp, both the output current and the output voltage are high. For this reason, a small amount of power can be used in the base period Tb, but a large amount of power is required in the peak period Tp.
  • the output power varies greatly during the main welding period.
  • the value of the base current Ib is handled as the set value of the output current setting signal Is in the base period Tb, and the value of the peak current Ip is set to the value of the output current setting signal Is in the peak period Tp. Treated as a setting value.
  • the relationship between the output current threshold Ith, the base current Ib, and the peak current Ip of pulse welding stored in the first memory circuit MC1 is as shown in FIGS.
  • the comparison signal Cc indicates driving of two inverter circuits. Therefore, the arc machining power supply device drives the two inverter circuits to output the peak current Ip.
  • the comparison signal Cc indicates driving of at least one inverter circuit.
  • the first inverter circuit INV1 and the second temperature are determined by the relationship between the temperature based on the first temperature measurement value T1 and the second temperature measurement value T2 and the power consumption with respect to this temperature. Driving or stopping of the inverter circuit INV2 is selected.
  • the arc machining power supply device drives one or two inverter circuits to output a base current Ib.
  • FIG. 1 An example of the relationship between the output current and output voltage in pulse welding and the number of inverter circuits to be driven will be specifically described with reference to FIG.
  • the figure shows an example in which one inverter is driven in the first to third base periods Tb and two inverters are driven in the fourth base period Tb.
  • the temperature of the switching elements constituting the inverter circuit increases.
  • the total power consumption may be smaller when two inverter circuits are driven than when one inverter circuit is driven.
  • the arithmetic circuit OC determines that driving one inverter circuit can reduce power consumption compared to driving two inverter circuits. . For this reason, the selection circuit SC selects driving of one inverter circuit. In contrast, in the fourth base period Tb, the arithmetic circuit OC determines that the power consumption is smaller when driven by two inverter circuits than when driven by one inverter circuit. Therefore, the selection circuit SC selects driving of the two inverter circuits.
  • the arc machining power supply device includes a plurality of inverter circuits provided in parallel and performs pulse welding on the workpiece M.
  • Pulse welding has a welding start period Th, a main welding period Tw, and a welding end period Te.
  • the power supply device for arc machining uses the measured temperature values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2), the base current and the peak current of the pulse welding, respectively.
  • the power consumption in the combination of driving and stopping operations of the inverter circuits (INV1, INV2) is calculated.
  • the arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption in the plurality of inverter circuits (INV1, INV2) is minimized.
  • the power consumption of the inverter circuits (INV1, INV2) constituting the arc machining power supply device during the main welding period Tw of the pulse welding can be reduced.
  • Embodiment 3 of the present disclosure will be described with reference to FIGS. 1 to 3A, FIG. 5, and FIGS. 8 to 11.
  • the configuration of the arc machining power supply device of the third embodiment is the same as that of the first embodiment.
  • the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current as shown in FIG.
  • the second memory circuit MC2 stores the relationship between the temperature of the switching element constituting the inverter circuit as shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit.
  • the first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation in the welding start period will be described with reference to FIGS.
  • a start current Ih higher than the average output current Iw in the main welding period is output for a certain period of time. To make it easier to start.
  • the arc machining power supply device performs a predetermined calculation on the basis of the average output current Iw set by the operator to determine the start current Ih.
  • the operator can directly adjust the starting current Ih.
  • the value of the start current Ih is treated as the set value of the output current setting signal Is.
  • the comparison signal Cc indicates driving of two inverter circuits. Therefore, as shown in FIGS. 8, 9, and 11, the arc machining power supply device drives two inverter circuits to output a start current Ih.
  • the temperature measurement values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2) and the main welding period Tw are used for the welding start period Th.
  • the power consumption in each inverter circuit (INV1, INV2) is calculated from the constant start current Ih.
  • the arc machining power supply device selects driving and stopping of the inverter circuits (INV1, INV2) so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits, is minimized.
  • the constant start current Ih may be higher than the average output current Iw.
  • start current Ih used to calculate the power consumption in the inverter circuits is a constant start current Ih, but may be an average start current Ihw.
  • the average start current Ihw is a current obtained by averaging the output current in the welding start period Th.
  • the average start current Ihw may be higher than the average output current Iw.
  • the configuration of the arc machining power supply device of the fourth embodiment is the same as that of the first embodiment.
  • the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current as shown in FIG.
  • the second memory circuit MC2 stores the relationship among the temperature of the switching elements constituting the inverter circuit as shown in FIG. 3A, the output current per inverter circuit, and the power consumption of the inverter circuit.
  • the first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation in the welding end period will be described with reference to FIGS. 5, 10, and 11.
  • the arc machining power supply device performs a predetermined calculation on the basis of the average output current Iw set by the operator to determine the termination current Ie.
  • the operator can also adjust the termination current Ie directly.
  • the value of the termination current Ie is treated as the set value of the output current setting signal Is.
  • the comparison signal Cc indicates driving of at least one inverter circuit.
  • the arc machining power supply device uses the first temperature measurement value T1 and the second temperature measurement value T2 based on the relationship between the temperature of the inverter circuit and the power consumption. The driving or stopping of INV1 and the second inverter circuit INV2 is selected. The arc machining power supply device drives the selected inverter circuit to output the termination current Ie. 8 and 11 show examples in which the termination current Ie is output by one inverter circuit.
  • FIG. 9 shows an example in which the termination current Ie is output by two inverter circuits.
  • the temperature measurement values (T1, T2) of the switching elements constituting the inverter circuits (INV1, INV2) and the constant termination current Ie are calculated from the above.
  • the arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits (INV1, INV2), is minimized.
  • the constant termination current Ie may be lower than the average output current Iw.
  • the termination current Ie used for calculating the power consumption in the inverter circuits is a constant termination current Ie lower than the average output current Iw, but the average termination current Ie is lower than the average output current Iw. It may be Iew.
  • This average terminal current Iew is a current obtained by averaging the output current in the welding end period Te. The average termination current Iew may be lower than the average output current Iw.
  • the technology of the present disclosure reduces power consumption by setting an appropriate output current setting signal Is in advance depending on the welding method and the welding period. Can be planned. Further, depending on any combination of the first to fourth embodiments, the power consumption can be reduced in the entire welding period including the welding start period, the main start period, and the welding end period.
  • a plurality of inverter circuits are driven or stopped according to a measured value of a temperature of a switching element constituting the inverter circuit and a set value related to an output current, and power consumption in the inverter circuit is reduced. Since it can be selected, it is industrially useful.

Abstract

The present invention selects whether a plurality of inverter circuits (INV1, INV2) are driven or stopped in accordance with the measured values of the temperatures of switching elements constituting the inverter circuits (INV1, INV2) and a setting value associated with an output current so that the power consumed by the inverter circuits (INV1, INV2) is minimized.

Description

アーク加工用電源装置およびアーク加工用電源装置の制御方法Power supply device for arc machining and control method for power supply device for arc machining
　本開示は、アーク加工用電源装置に内蔵されているインバータ回路を複数並列に設けて、並列運転する技術に関するものである。 This disclosure relates to a technique for providing a plurality of inverter circuits built in an arc machining power supply device in parallel and operating in parallel.
　アーク加工用電源装置において、溶接電流としての出力電流の増大をはかるためにインバータ回路を複数並列に設け並列運転を行って対応してきた。 In the arc machining power supply device, in order to increase the output current as the welding current, a plurality of inverter circuits are provided in parallel to perform parallel operation.
　一方、上記のようなインバータ回路が複数並列に設けられたアーク加工用電源装置において、特に出力電流が小さい場合は、いくつかのインバータ回路を停止させるほうが、全てのインバータ回路を駆動させるよりも、溶接性が改善される場合がある。 On the other hand, in the arc machining power supply apparatus provided with a plurality of inverter circuits as described above, especially when the output current is small, it is better to stop some inverter circuits than to drive all inverter circuits. Weldability may be improved.
　インバータ回路が複数並列に設けられた従来のアーク加工用電源装置では、インバータ回路の出力制御信号のパルス波形の歯抜けを検出して、あるインバータ回路を停止させる、という方法が開示されている（特許文献１）。 In a conventional arc machining power supply device in which a plurality of inverter circuits are provided in parallel, a method is disclosed in which a certain inverter circuit is stopped by detecting a missing tooth in the pulse waveform of the output control signal of the inverter circuit ( Patent Document 1).
特許第４９６５２３８号公報Japanese Patent No. 4965238
　しかしながら、前記従来の構成では、あるインバータ回路を停止させることにより、アーク加工用電源装置の全体での消費電力が増大する場合がある。 However, in the conventional configuration, the power consumption of the entire arc machining power supply device may increase by stopping a certain inverter circuit.
　本開示は、インバータ回路が複数並列に設けられたアーク加工用電源装置において、アーク加工用電源装置の消費電力が小さくなるように制御する手法を提供する。 The present disclosure provides a technique for controlling the power consumption of the arc machining power supply apparatus to be small in the arc machining power supply apparatus in which a plurality of inverter circuits are provided in parallel.
　本開示の一態様のアーク加工用電源装置は、被溶接物に対して短絡溶接またはパルス溶接を行うアーク加工用電源装置であって、商用交流電力を整流し直流電圧を出力する第１の１次整流回路と、第１の１次整流回路から出力された直流電圧を平滑する第１の平滑コンデンサと、第１の平滑コンデンサで平滑された直流電圧を高周波交流電圧に変換する第１のインバータ回路と、第１のインバータ回路の出力をアーク加工に適した高周波交流電圧に変換する第１の主変圧器と、第１の主変圧器の出力を整流する第１の２次整流回路と、商用交流電力を整流し直流電圧を出力する第２の１次整流回路と、第２の１次整流回路から出力された直流電圧を平滑する第２の平滑コンデンサと、第２の平滑コンデンサで平滑された直流電圧を高周波交流電圧に変換する第２のインバータ回路と、第２のインバータ回路の出力をアーク加工に適した高周波交流電圧に変換する第２の主変圧器と、第２の主変圧器の出力を整流する第２の２次整流回路と、第１の２次整流回路の出力と前記第２の２次整流回路の出力を合わせた電流を平滑して出力端子に出力電流を出力する直流リアクトルと、出力電流の検出を行う出力電流検出回路と、予め定めた出力電流に係る設定値を設定する出力電流設定回路と、出力電流に対応する駆動が必要なインバータ回路の最少の個数を予め記憶する第１の記憶回路と、出力電流設定回路によって設定された出力電流に係る設定値と第１の記憶回路に記憶されている出力電流に対応する駆動が必要なインバータ回路の最少の個数とを比較して、設定に対応する駆動が必要なインバータ回路の最少の個数を求める比較回路と、インバータ回路を構成するスイッチング素子の温度と駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力との関係である温度に対する消費電力の関係を予め記憶する第２の記憶回路と、出力電流設定回路によって設定された出力電流に係る設定値と、第１のインバータ回路を構成するスイッチング素子の測定された温度と、第２のインバータ回路を構成するスイッチング素子の測定された温度と、第２の記憶回路の記憶されている温度に対する消費電力パラメータから、各インバータ回路の駆動と停止の組合せに対する消費電力を求める演算回路と、比較回路より求めた設定に対応する駆動が必要なインバータ回路の最少の個数以上で、演算回路で求めた消費電力の中で最も消費電力が小さくなるインバータ回路の組合せを選択する選択回路と、選択回路により選択されたインバータ回路の組合せに基づいて、第１のインバータ回路を制御する第１の出力制御信号と第２のインバータ回路を制御する第２の出力制御信号を出力する出力制御回路と、を備えるものである。 An arc machining power supply apparatus according to an aspect of the present disclosure is an arc machining power supply apparatus that performs short-circuit welding or pulse welding on an object to be welded, and is a first 1 that rectifies commercial AC power and outputs a DC voltage. A first rectifier circuit, a first smoothing capacitor that smoothes the DC voltage output from the first primary rectifier circuit, and a first inverter that converts the DC voltage smoothed by the first smoothing capacitor into a high-frequency AC voltage A circuit, a first main transformer that converts the output of the first inverter circuit into a high-frequency AC voltage suitable for arc machining, a first secondary rectifier circuit that rectifies the output of the first main transformer, Smoothed by a second primary rectifier circuit that rectifies commercial AC power and outputs a DC voltage, a second smoothing capacitor that smoothes the DC voltage output from the second primary rectifier circuit, and a second smoothing capacitor High frequency AC A second inverter circuit for converting to a voltage; a second main transformer for converting the output of the second inverter circuit to a high-frequency AC voltage suitable for arc machining; and a second for rectifying the output of the second main transformer. A secondary rectifier circuit, a DC reactor for smoothing a current obtained by combining an output of the first secondary rectifier circuit and an output of the second secondary rectifier circuit, and outputting an output current to an output terminal, and an output current An output current detection circuit for detecting the output current; an output current setting circuit for setting a preset value related to a predetermined output current; and a first number that stores in advance a minimum number of inverter circuits that require driving corresponding to the output current Comparing the storage circuit, the set value related to the output current set by the output current setting circuit and the minimum number of inverter circuits that need to be driven corresponding to the output current stored in the first storage circuit, Drive corresponding to the setting Comparison circuit for obtaining the minimum number of necessary inverter circuits, power consumption with respect to temperature, which is the relationship between the temperature of the switching elements constituting the inverter circuit, the inverter output current per inverter circuit to be driven, and the power consumption of the inverter circuit A second storage circuit for storing the relationship in advance, a set value relating to the output current set by the output current setting circuit, a measured temperature of the switching element constituting the first inverter circuit, and a second inverter An arithmetic circuit for obtaining power consumption for a combination of driving and stopping of each inverter circuit from a power consumption parameter for the measured temperature of the switching elements constituting the circuit and the temperature stored in the second storage circuit, and a comparison circuit More than the minimum number of inverter circuits that need to be driven to meet the required setting, A selection circuit that selects a combination of inverter circuits that consumes the least power among the obtained power consumption, and a first output that controls the first inverter circuit based on the combination of inverter circuits selected by the selection circuit An output control circuit for outputting a control signal and a second output control signal for controlling the second inverter circuit.
　本開示の別の態様のアーク加工用電源装置の制御方法は、インバータ回路が複数並列に設けられ、被溶接物に対して、溶接開始期間、本溶接期間、および溶接終了期間を有する短絡溶接を行うアーク加工用電源装置の制御方法であって、短絡溶接の本溶接期間については、インバータ回路を構成するスイッチング素子の温度の測定値と、被溶接物に対して出力される出力電流の時間平均である平均出力電流とからそれぞれのインバータ回路の動作の組合せにおける消費電力を演算し、複数のインバータ回路それぞれでの消費電力の合計が最も小さくなるように複数の前記インバータ回路の駆動と停止を選択するものである。 According to another aspect of the present disclosure, there is provided a control method for a power supply device for arc machining, in which a plurality of inverter circuits are provided in parallel, and short-circuit welding having a welding start period, a main welding period, and a welding end period is performed on a workpiece. A method of controlling a power supply device for arc machining to be performed. For the main welding period of short-circuit welding, the measured value of the temperature of the switching element constituting the inverter circuit and the time average of the output current output to the work piece The power consumption in the combination of the operation of each inverter circuit is calculated from the average output current, and the driving and stopping of the plurality of inverter circuits are selected so that the total power consumption in each of the plurality of inverter circuits is minimized. To do.
　本開示のさらに別の態様のアーク加工用電源装置の制御方法は、インバータ回路が複数並列に設けられ、被溶接物に対して、溶接開始期間、本溶接期間、および溶接終了期間を有するパルス溶接を行うアーク加工用電源装置の制御方法であって、パルス溶接の本溶接期間については、インバータ回路を構成するスイッチング素子の温度の測定値とパルス溶接のベース電流およびピーク電流とからそれぞれのインバータ回路の動作の組合せにおける消費電力を演算し、複数の前記インバータ回路での消費電力の合計が最も小さくなるように複数のインバータ回路それぞれの駆動と停止を選択するものである。 According to still another aspect of the present disclosure, there is provided a method for controlling a power supply device for arc machining, in which a plurality of inverter circuits are provided in parallel and a pulse welding having a welding start period, a main welding period, and a welding end period with respect to an object For the arc welding power supply apparatus, and for the main welding period of the pulse welding, each inverter circuit is based on the measured value of the temperature of the switching element constituting the inverter circuit and the base current and peak current of the pulse welding. The power consumption in the combination of operations is calculated, and driving and stopping of each of the plurality of inverter circuits are selected so that the total power consumption in the plurality of inverter circuits is minimized.
　本開示の一態様に係るアーク加工用電源装置は、複数並列に接続された電源ユニットを備える大電流対応のアーク加工用電源装置である。各電源ユニットは、１次整流回路、平滑コンデンサ、インバータ回路、主変圧器及び２次整流回路を含む。アーク加工用電源装置は、各インバータ回路を構成するスイッチング素子の温度を測定し、それらに基づいて各インバータ回路での消費電力が最も小さくなるように各インバータ回路の駆動または停止を決定する。したがって、アーク加工用電源装置の消費電力を低減することができる。 The arc machining power supply device according to an aspect of the present disclosure is a large current compatible arc machining power supply device including a plurality of power supply units connected in parallel. Each power supply unit includes a primary rectifier circuit, a smoothing capacitor, an inverter circuit, a main transformer, and a secondary rectifier circuit. The arc machining power supply device measures the temperature of the switching elements constituting each inverter circuit, and based on them, determines whether to drive or stop each inverter circuit so that the power consumption in each inverter circuit is minimized. Therefore, the power consumption of the arc machining power supply device can be reduced.
図１は、電源ユニットが２個並列に設けられたアーク加工用電源装置の電気接続図である。FIG. 1 is an electrical connection diagram of an arc machining power supply device in which two power supply units are provided in parallel. 図２は、電源ユニットが２個並列に設けられたアーク加工用電源装置における、第１の記憶回路に記憶される情報の一例、すなわち、出力電流に対応する駆動が必要なインバータ回路の最少の個数の関係の一例を示す図である。FIG. 2 shows an example of information stored in the first storage circuit in the arc machining power supply apparatus in which two power supply units are provided in parallel, that is, the minimum number of inverter circuits that need to be driven corresponding to the output current. It is a figure which shows an example of the relationship of a number. 図３Ａは、電源ユニットが２個並列に設けられたアーク加工用電源装置における、第２の記憶回路に記憶される情報の一例、すなわち、温度に対する消費電力の関係の一例、より詳しくは、インバータ回路の温度毎の、駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力との関係の一例を示す図である。FIG. 3A shows an example of information stored in the second storage circuit in the arc machining power supply device in which two power supply units are provided in parallel, that is, an example of the relationship of power consumption with respect to temperature. It is a figure which shows an example of the relationship between the inverter output current per inverter circuit to drive, and the power consumption of an inverter circuit for every temperature of a circuit. 図３Ｂは、温度に対する消費電力の関係の別の一例を示す図である。FIG. 3B is a diagram illustrating another example of the relationship of power consumption with respect to temperature. 図４は、電源ユニットが２個並列に設けられたアーク加工用電源装置における演算回路の演算結果の一例を示す図である。FIG. 4 is a diagram illustrating an example of a calculation result of the calculation circuit in the arc machining power supply device in which two power supply units are provided in parallel. 図５は、短絡溶接時の出力電流波形と出力電圧波形の一例を示す図である。FIG. 5 is a diagram illustrating an example of an output current waveform and an output voltage waveform during short-circuit welding. 図６Ａは、各インバータ回路の駆動と停止の組合せに対する常温領域でのインバータ回路の消費電力を示す図である。FIG. 6A is a diagram illustrating the power consumption of the inverter circuit in a normal temperature region with respect to a combination of driving and stopping of each inverter circuit. 図６Ｂは、各インバータ回路の駆動と停止の組合せに対する高温領域でのインバータ回路の消費電力を示す図である。FIG. 6B is a diagram illustrating the power consumption of the inverter circuit in a high temperature region with respect to a combination of driving and stopping of each inverter circuit. 図７は、演算回路の演算結果を示す図である。FIG. 7 is a diagram illustrating a calculation result of the calculation circuit. 図８は、短絡溶接時の出力電流と出力電圧と駆動するインバータ回路の個数の関係の一例を示す図である。FIG. 8 is a diagram illustrating an example of the relationship between the output current and output voltage during short-circuit welding and the number of inverter circuits to be driven. 図９は、短絡溶接時の出力電流と出力電圧と駆動するインバータ回路の個数の関係の一例を示す図である。FIG. 9 is a diagram illustrating an example of the relationship between the output current and output voltage during short-circuit welding and the number of inverter circuits to be driven. 図１０は、パルス溶接時の出力電流波形と出力電圧波形の一例を示す図である。FIG. 10 is a diagram illustrating an example of an output current waveform and an output voltage waveform during pulse welding. 図１１は、パルス溶接時の出力電流と出力電圧と駆動するインバータ回路の個数の関係の一例を示す図である。FIG. 11 is a diagram illustrating an example of the relationship between the output current and the output voltage during pulse welding and the number of inverter circuits to be driven.
　（実施の形態１）
　以下、本開示の実施の形態１について、図１から図９を用いて説明をする。まず、アーク加工用電源装置の構成について図１から図４を用いて説明する。図１は、１次整流回路、平滑コンデンサ、インバータ回路、主変圧器及び２次整流回路から形成される電源ユニットを２個並列に設けたアーク加工用電源装置を示す。 (Embodiment 1)
Hereinafter, the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 9. First, the configuration of the arc machining power supply device will be described with reference to FIGS. FIG. 1 shows an arc machining power supply device in which two power supply units formed of a primary rectifier circuit, a smoothing capacitor, an inverter circuit, a main transformer, and a secondary rectifier circuit are provided in parallel.
　商用交流電源ＡＣからの交流電力を整流して直流電圧を出力する第１の１次整流回路ＤＲ１１と、直流電圧を平滑する第１の平滑コンデンサＣ１とで直流電源回路が形成される。また、第２の１次整流回路ＤＲ１２と第２の平滑コンデンサＣ２は、第１の１次整流回路ＤＲ１１と並列に設けられており、それぞれ第１の１次整流回路ＤＲ１１と直流電圧を平滑する第１の平滑コンデンサＣ１と同じ動作をする。 A DC power supply circuit is formed by the first primary rectifier circuit DR11 that rectifies AC power from the commercial AC power supply AC and outputs a DC voltage, and the first smoothing capacitor C1 that smoothes the DC voltage. The second primary rectifier circuit DR12 and the second smoothing capacitor C2 are provided in parallel with the first primary rectifier circuit DR11, and smooth the DC voltage with the first primary rectifier circuit DR11, respectively. The same operation as that of the first smoothing capacitor C1 is performed.
　第１のインバータ回路ＩＮＶ１はＩＧＢＴやＭＯＳＦＥＴなどのスイッチング素子によって形成される。第１のインバータ回路ＩＮＶ１は、第１の１次整流回路ＤＲ１１によって出力された直流電圧を高周波交流電圧に変換して出力する。また、第２のインバータ回路ＩＮＶ２は第２の１次整流回路ＤＲ１２によって出力された直流電圧を高周波交流電圧に変換して出力する。 The first inverter circuit INV1 is formed by a switching element such as an IGBT or a MOSFET. The first inverter circuit INV1 converts the DC voltage output by the first primary rectifier circuit DR11 into a high-frequency AC voltage and outputs it. The second inverter circuit INV2 converts the DC voltage output by the second primary rectifier circuit DR12 into a high-frequency AC voltage and outputs it.
　第１の主変圧器ＭＴＲ１は第１のインバータ回路ＩＮＶ１から出力された高周波交流電圧をアーク加工に適した高周波交流電圧に変換する。第１の２次整流回路ＤＲ２１は第１の主変圧器ＭＴＲ１の出力を整流し直流電流を出力する。 The first main transformer MTR1 converts the high-frequency AC voltage output from the first inverter circuit INV1 into a high-frequency AC voltage suitable for arc machining. The first secondary rectifier circuit DR21 rectifies the output of the first main transformer MTR1 and outputs a direct current.
　第２の主変圧器ＭＴＲ２は第２のインバータ回路ＩＮＶ２から出力された高周波交流電圧をアーク加工に適した高周波交流電圧に変換する。第２の２次整流回路ＤＲ２２は第２の主変圧器ＭＴＲ２の出力を整流し直流電流を出力する。 The second main transformer MTR2 converts the high-frequency AC voltage output from the second inverter circuit INV2 into a high-frequency AC voltage suitable for arc machining. The second secondary rectifier circuit DR22 rectifies the output of the second main transformer MTR2 and outputs a direct current.
　直流リアクトルＤＣＬは第１の２次整流回路ＤＲ２１から出力された直流電流と第２の２次整流回路ＤＲ２２から出力された直流電流とを合わせた直流電流を平滑する。 The DC reactor DCL smoothes a DC current that is a combination of the DC current output from the first secondary rectifier circuit DR21 and the DC current output from the second secondary rectifier circuit DR22.
　出力端子ＯＴとトーチＴＨとの間と、出力端子ＯＴと被加工物Ｍとのそれぞれの間には、作業者によって電気的接続ができる電線などが取り付けられる。出力端子ＯＴは、トーチＴＨと被加工物Ｍとの間に直流リアクトルＤＣＬによって平滑された直流電流を溶接電流として供給する。 An electric wire that can be electrically connected by an operator is attached between the output terminal OT and the torch TH and between the output terminal OT and the workpiece M. The output terminal OT supplies a direct current smoothed by the direct current reactor DCL between the torch TH and the workpiece M as a welding current.
　出力電流検出回路ＣＴは、溶接電流としての出力電流を検出し、検出された出力電流を示す出力電流検出信号Ｉｏを出力する。出力電流は、第１の２次整流回路ＤＲ２１の出力の直流電流と第２の２次整流回路ＤＲ２２の出力の直流電流とを合わせた直流電流である。 The output current detection circuit CT detects an output current as a welding current, and outputs an output current detection signal Io indicating the detected output current. The output current is a direct current obtained by adding the direct current output from the first secondary rectifier circuit DR21 and the direct current output from the second secondary rectifier circuit DR22.
　出力電流設定回路ＩＳは、作業者によって予め調整される出力電流に係る設定値を出力電流設定信号Ｉｓとして出力する。 The output current setting circuit IS outputs a set value related to the output current that is adjusted in advance by the operator as the output current setting signal Is.
　第１の記憶回路ＭＣ１は、出力電流に対する最低限、駆動が必要なインバータ回路の最少の個数の関係を予め記憶している。ここでは、インバータ回路とは、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２のことである。第１の記憶回路ＭＣ１は、この記憶された関係を第１の記憶信号Ｍｃ１として出力する。例えば、図２に示すように、第１の記憶回路ＭＣ１は出力電流に対応する駆動が必要なインバータ回路の最少の個数の関係を記憶している。出力電流が出力電流閾値Ｉｔｈ未満の電流値の場合、少なくとも１個のインバータ回路の駆動が必要である。出力電流が出力電流閾値Ｉｔｈ以上の電流値の場合、少なくとも２個のインバータ回路の駆動が必要である。 The first storage circuit MC1 stores in advance the relationship between the minimum number of inverter circuits that need to be driven at the minimum with respect to the output current. Here, the inverter circuits are the first inverter circuit INV1 and the second inverter circuit INV2. The first memory circuit MC1 outputs this stored relationship as the first memory signal Mc1. For example, as shown in FIG. 2, the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven corresponding to the output current. When the output current has a current value less than the output current threshold Ith, at least one inverter circuit needs to be driven. When the output current has a current value equal to or greater than the output current threshold Ith, it is necessary to drive at least two inverter circuits.
　図１に示す、比較回路ＣＣは出力電流設定信号Ｉｓと第１の記憶信号Ｍｃ１を比較して、駆動が必要なインバータ回路の最少の個数を比較信号Ｃｃとして出力する。 The comparison circuit CC shown in FIG. 1 compares the output current setting signal Is and the first storage signal Mc1, and outputs the minimum number of inverter circuits that need to be driven as the comparison signal Cc.
　第２の記憶回路ＭＣ２は、温度に対するインバータ回路の消費電力の関係を記憶しており、この関係を第２の記憶信号Ｍｃ２として出力する。この関係は、より詳しくは、インバータ回路を構成するスイッチング素子の温度に対する、駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力との関係である。例えば、第２の記憶回路ＭＣ２は図３Ａに示すような温度に対する駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力との関係を記憶している。同図から明らかなように、駆動するインバータ回路１個あたりの出力電流が増大すればインバータ回路の消費電力も増大する傾向がある。また、温度領域が例えば８０～９０℃の高温であれば、５～３５℃の常温に比べて、駆動するインバータ回路１個あたりのインバータ出力電流に対する消費電力の傾きが増加する。 The second storage circuit MC2 stores the relationship of the power consumption of the inverter circuit with respect to the temperature, and outputs this relationship as the second storage signal Mc2. More specifically, this relationship is the relationship between the inverter output current per inverter circuit to be driven and the power consumption of the inverter circuit with respect to the temperature of the switching elements constituting the inverter circuit. For example, the second memory circuit MC2 stores the relationship between the inverter output current per inverter circuit to be driven with respect to the temperature and the power consumption of the inverter circuit as shown in FIG. 3A. As is apparent from the figure, if the output current per one inverter circuit to be driven increases, the power consumption of the inverter circuit tends to increase. In addition, when the temperature region is a high temperature of, for example, 80 to 90 ° C., the slope of power consumption with respect to the inverter output current per inverter circuit to be driven increases as compared with a normal temperature of 5 to 35 ° C.
　反対に、図３Ｂのように温度領域が高温であれば、常温に比べて、駆動するインバータ回路１個あたりのインバータ出力電流に対する消費電力の傾きが減少する場合もある。第２の記憶回路ＭＣ２に記憶される温度に対するインバータ回路の消費電力の関係は、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２を構成するスイッチング素子（ＩＧＢＴやＭＯＳＦＥＴ）の仕様書などから決定できる。 On the other hand, when the temperature region is high as shown in FIG. 3B, the slope of power consumption with respect to the inverter output current per inverter circuit to be driven may decrease as compared with normal temperature. The relationship of the power consumption of the inverter circuit with respect to the temperature stored in the second memory circuit MC2 is determined from the specifications of the switching elements (IGBT and MOSFET) constituting the first inverter circuit INV1 and the second inverter circuit INV2. it can.
　図１に示す、第１の温度測定値Ｔ１は、第１のインバータ回路ＩＮＶ１を構成するスイッチング素子の温度測定値である。また、第２の温度測定値Ｔ２は、第２のインバータ回路ＩＮＶ２を構成するスイッチング素子の温度測定値である。これらのスイッチング素子の温度は、図示しないサーミスタなどによって測定される。 The first measured temperature value T1 shown in FIG. 1 is a measured temperature value of the switching elements constituting the first inverter circuit INV1. The second temperature measurement value T2 is a temperature measurement value of the switching element that constitutes the second inverter circuit INV2. The temperature of these switching elements is measured by a thermistor (not shown).
　演算回路ＯＣは、各インバータ回路の駆動と停止の組み合わせに対する全インバータ回路の合計の消費電力を演算する。この合計の消費電力は、第１の温度測定値Ｔ１と、第２の温度測定値Ｔ２と、第２の記憶信号Ｍｃ２に基づいて得られる。演算回路ＯＣは、この演算結果を演算信号Ｏｃとして出力する。例えば、演算回路ＯＣによる、各インバータ回路の組合せでの消費電力の演算結果は図４に示すようになる。第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２の駆動と停止の組合せは３通りある（両方停止の場合を除く）。演算回路ＯＣは、それぞれの場合の合計消費電力Ｗｗ３である消費電力値Ｗ２１、Ｗ２２、Ｗ４３（Ｗ３１＋Ｗ３２）を演算する。 The arithmetic circuit OC calculates the total power consumption of all inverter circuits for the combination of driving and stopping of each inverter circuit. This total power consumption is obtained based on the first temperature measurement value T1, the second temperature measurement value T2, and the second storage signal Mc2. The arithmetic circuit OC outputs the calculation result as the calculation signal Oc. For example, the calculation result of the power consumption in the combination of each inverter circuit by the arithmetic circuit OC is as shown in FIG. There are three combinations of driving and stopping of the first inverter circuit INV1 and the second inverter circuit INV2 (except when both are stopped). The arithmetic circuit OC calculates power consumption values W21, W22, and W43 (W31 + W32) that are the total power consumption Ww3 in each case.
　ここで消費電力値Ｗ２１は第１のインバータ回路ＩＮＶ１が駆動し、第２のインバータ回路ＩＮＶ２が停止した時の合計消費電力の値、すなわち、第１のインバータ回路ＩＮＶ１が１個だけ駆動したときの合計消費電力の値である。また、消費電力値Ｗ２２は第１のインバータ回路ＩＮＶ１が停止し、第２のインバータ回路ＩＮＶ２が駆動した時の合計消費電力の値、すなわち、第２のインバータ回路ＩＮＶ２が１個だけ駆動したときの合計消費電力の値である。また、消費電力値Ｗ４３は、インバータ回路が２個駆動して、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２とが共に駆動した時の合計消費電力の値、すなわち、第１のインバータ回路ＩＮＶ１の消費電力値Ｗ３１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗ３２の和の消費電力の値である。 Here, the power consumption value W21 is the total power consumption when the first inverter circuit INV1 is driven and the second inverter circuit INV2 is stopped, that is, when only one first inverter circuit INV1 is driven. This is the total power consumption value. The power consumption value W22 is the total power consumption when the first inverter circuit INV1 is stopped and the second inverter circuit INV2 is driven, that is, when only one second inverter circuit INV2 is driven. This is the total power consumption value. The power consumption value W43 is a value of the total power consumption when the two inverter circuits are driven and the first inverter circuit INV1 and the second inverter circuit INV2 are driven together, that is, the first inverter circuit. This is the sum of the power consumption value W31 of INV1 and the power consumption value W32 of the second inverter circuit INV2.
　図１に示す、選択回路ＳＣは駆動が必要なインバータ回路の最少の個数以上の組み合わせの中で第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２の合計の消費電力が最も小さくなる組み合わせを選択する。この選択結果は、比較信号Ｃｃと演算信号Ｏｃに基づいて得られる。選択回路ＳＣは、各インバータ回路の駆動または停止に関する選択結果を選択信号Ｓｃとして出力する。 The selection circuit SC shown in FIG. 1 selects the combination that minimizes the total power consumption of the first inverter circuit INV1 and the second inverter circuit INV2 among the combinations of the minimum number of inverter circuits that need to be driven. To do. This selection result is obtained based on the comparison signal Cc and the calculation signal Oc. The selection circuit SC outputs a selection result related to driving or stopping of each inverter circuit as a selection signal Sc.
　出力制御回路ＯＣＣは、出力電流検出信号Ｉｏが出力電流設定信号Ｉｓと等しくなるように、選択信号Ｓｃで駆動が選択されたインバータ回路の出力を制御する。出力制御回路ＯＣＣは、さらに、選択信号Ｓｃで停止が選択されたインバータ回路の出力を０になるように制御する。出力制御回路ＯＣＣは、第１のインバータ回路ＩＮＶ１の出力を制御するための第１の出力制御信号Ｏｃｃ１と第２のインバータ回路ＩＮＶ２の出力を制御するための第２の出力制御信号Ｏｃｃ２を出力する。 The output control circuit OCC controls the output of the inverter circuit whose drive is selected by the selection signal Sc so that the output current detection signal Io becomes equal to the output current setting signal Is. The output control circuit OCC further controls the output of the inverter circuit whose stop is selected by the selection signal Sc to be zero. The output control circuit OCC outputs a first output control signal Occ1 for controlling the output of the first inverter circuit INV1 and a second output control signal Occ2 for controlling the output of the second inverter circuit INV2. .
　第１のインバータ駆動回路ＳＤ１は、第１の出力制御信号Ｏｃｃ１に応じて第１のインバータ回路ＩＮＶ１を駆動するための第１のインバータ駆動信号Ｓｄ１を出力する。また、第２のインバータ駆動回路ＳＤ２は、第２の出力制御信号Ｏｃｃ２に応じて第２のインバータ回路ＩＮＶ２を駆動するための第２のインバータ駆動信号Ｓｄ２を出力する。 The first inverter drive circuit SD1 outputs a first inverter drive signal Sd1 for driving the first inverter circuit INV1 according to the first output control signal Occ1. The second inverter drive circuit SD2 outputs a second inverter drive signal Sd2 for driving the second inverter circuit INV2 according to the second output control signal Occ2.
　このように、図１に示す構成のアーク加工用電源装置において、第１の記憶回路ＭＣ１は図２に示す出力電流に対する駆動が必要なインバータ回路の最少の個数の関係を記憶している。第２の記憶回路ＭＣ２は図３Ａに示すインバータ回路を構成するスイッチング素子の温度と駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力の関係を記憶している。 As described above, in the arc machining power supply device having the configuration shown in FIG. 1, the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current shown in FIG. The second memory circuit MC2 stores the relationship between the temperature of the switching element constituting the inverter circuit shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit.
　次に、図５から図９を用いて、短絡アーク溶接である短絡溶接の動作を説明する。短絡溶接は、溶接開始期間Ｔｈ、本溶接期間Ｔｗ、溶接終了期間Ｔｅを含む。本溶接期間は、短絡状態の短絡期間Ｔｓとアーク状態のアーク期間Ｔａとを繰り返す期間である。以下の説明では、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２が同じスイッチング素子で構成されていることとする。なお、同じスイッチング素子とは、型式が同じであり、言い換えると同性能のスイッチング素子のことを示す。 Next, the operation of short circuit welding which is short circuit arc welding will be described with reference to FIGS. The short-circuit welding includes a welding start period Th, a main welding period Tw, and a welding end period Te. The main welding period is a period in which the short circuit period Ts in the short circuit state and the arc period Ta in the arc state are repeated. In the following description, it is assumed that the first inverter circuit INV1 and the second inverter circuit INV2 are configured by the same switching element. The same switching element has the same model, in other words, a switching element having the same performance.
　図５は、短絡溶接時の出力電流波形と出力電圧波形を示している。本溶接期間Ｔｗは、被加工物Ｍの溶接をしたい箇所（溶接線）に従ってトーチＴＨを移動させて溶接を行っている期間である。平均出力電流Ｉｗは、本溶接期間Ｔｗにおける、溶接ワイヤと被加工物Ｍの間に供給される、言い換えると被加工物Ｍに対して出力される出力電流を時間平均したものである。平均出力電流Ｉｗは、本溶接期間Ｔｗにおける出力電流の設定値としての設定電流に相当する。溶接開始期間Ｔｈは本溶接期間Ｔｗの平均出力電流Ｉｗよりも高い開始電流Ｉｈを一定時間出力して、溶接を開始しやすくする処理を行う期間である。溶接終了期間Ｔｅは本溶接期間Ｔｗの平均出力電流Ｉｗよりも低い終端電流Ｉｅを一定時間出力して、溶接ワイヤと被加工物Ｍがくっついてしまうのを防ぐ処理を行う期間である。基本的に作業者は、本溶接期間Ｔｗにおける平均出力電流Ｉｗを調整して被加工物Ｍに合った溶接を行う。 FIG. 5 shows an output current waveform and an output voltage waveform during short-circuit welding. The main welding period Tw is a period during which welding is performed by moving the torch TH in accordance with a location (welding line) where the workpiece M is desired to be welded. The average output current Iw is a time average of the output current supplied between the welding wire and the workpiece M in the main welding period Tw, in other words, output to the workpiece M. The average output current Iw corresponds to a set current as a set value of the output current in the main welding period Tw. The welding start period Th is a period during which a process for making it easy to start welding by outputting a start current Ih higher than the average output current Iw of the main welding period Tw for a certain period of time. The welding end period Te is a period during which a terminal current Ie lower than the average output current Iw of the main welding period Tw is output for a certain period of time to prevent the welding wire and the workpiece M from sticking to each other. Basically, an operator adjusts the average output current Iw in the main welding period Tw and performs welding suitable for the workpiece M.
　上述の通り、短絡溶接の本溶接期間Ｔｗは、短絡期間Ｔｓとアーク期間Ｔａを含む。短絡期間Ｔｓは、溶接ワイヤと被加工物Ｍが電気的に接触（短絡）している短絡状態の期間である。アーク期間Ｔａは、短絡が開放されアークが発生しているアーク状態の期間である。図５に示すように、短絡期間Ｔｓでは、出力電圧が低くなっている。一方、アーク期間Ｔａでは、出力電圧が上昇し、出力電流が高い電流値より下降している。このように短絡溶接における本溶接期間の出力電力は、平均出力電流Ｉｗの設定値が一定であれば、多少の変動はあるもののある程度一定となる。 As described above, the main welding period Tw of the short circuit welding includes the short circuit period Ts and the arc period Ta. The short circuit period Ts is a short circuit period in which the welding wire and the workpiece M are in electrical contact (short circuit). The arc period Ta is an arc state period in which a short circuit is opened and an arc is generated. As shown in FIG. 5, the output voltage is low in the short circuit period Ts. On the other hand, in the arc period Ta, the output voltage increases and the output current decreases from a high current value. As described above, the output power in the main welding period in the short-circuit welding is constant to some extent although there is some variation if the set value of the average output current Iw is constant.
　そこで、短絡溶接における本溶接期間については、作業者により設定された平均出力電流Ｉｗの値が出力電流設定信号Ｉｓの設定値として扱うことができる。第１の記憶回路ＭＣ１に記憶されている出力電流閾値Ｉｔｈ（図２参照）に対して、平均出力電流Ｉｗの設定値が大きい場合は、比較信号Ｃｃは２個のインバータ回路の駆動を示す。一方、出力電流閾値Ｉｔｈに対して、平均出力電流Ｉｗの設定値が小さい場合は、比較信号Ｃｃは少なくとも１個のインバータ回路の駆動を示す。この場合は、第１の温度測定値Ｔ１と第２の温度測定値Ｔ２によって駆動するインバータ回路の最少の個数が変化する。 Therefore, for the main welding period in short-circuit welding, the value of the average output current Iw set by the operator can be handled as the set value of the output current setting signal Is. When the set value of the average output current Iw is larger than the output current threshold Ith (see FIG. 2) stored in the first memory circuit MC1, the comparison signal Cc indicates driving of two inverter circuits. On the other hand, when the set value of the average output current Iw is smaller than the output current threshold Ith, the comparison signal Cc indicates driving of at least one inverter circuit. In this case, the minimum number of inverter circuits driven by the first temperature measurement value T1 and the second temperature measurement value T2 changes.
　ここでは、出力電流閾値Ｉｔｈに対して、平均出力電流Ｉｗの設定値が小さい場合について説明する。 Here, a case where the set value of the average output current Iw is smaller than the output current threshold Ith will be described.
　例えば、消費電力の増加の傾きが高温領域に比べて常温領域では小さいインバータ回路のスイッチング素子の特性を図３Ａに示す。インバータ回路１個あたりの出力電流が増大すればインバータ回路の消費電力も増大する傾向がある。加えて、消費電力の増加の傾きは高温領域に比べて常温領域では小さい。常温領域では、駆動するインバータ回路１個あたりの出力電流が増大しても消費電力の増加率は小さい。 For example, FIG. 3A shows the characteristics of the switching element of the inverter circuit in which the slope of increase in power consumption is smaller in the normal temperature region than in the high temperature region. If the output current per inverter circuit increases, the power consumption of the inverter circuit tends to increase. In addition, the slope of increase in power consumption is smaller in the normal temperature region than in the high temperature region. In the normal temperature region, even if the output current per one inverter circuit to be driven increases, the rate of increase in power consumption is small.
　なお、高温領域とは、常温領域よりも高温であり、かつ、インバータ回路のスイッチング素子が壊れない程度の温度であり、例えば８０～９０℃の温度である。また常温領域とは、例えば５～３５℃の温度である。 The high temperature region is a temperature that is higher than the normal temperature region and that does not break the switching elements of the inverter circuit, and is, for example, a temperature of 80 to 90 ° C. The normal temperature region is, for example, a temperature of 5 to 35 ° C.
　アーク加工用電源装置のインバータ回路が十分に冷えている常温領域の状態である溶接開始前に、第１の温度測定値Ｔ１と第２の温度測定値Ｔ２がほぼ同じ値であったとする。この場合、インバータ出力電流とインバータ回路の消費電力との関係は、例えば図６Ａに示すような関係になる。インバータ回路の温度が常温領域のため、駆動するインバータ回路１個あたりのインバータ出力電流の増加に対するインバータ回路の消費電力の増加の傾きは小さい。 Suppose that the first temperature measurement value T1 and the second temperature measurement value T2 are substantially the same before the start of welding in a room temperature region where the inverter circuit of the arc machining power supply device is sufficiently cooled. In this case, the relationship between the inverter output current and the power consumption of the inverter circuit is, for example, as shown in FIG. 6A. Since the temperature of the inverter circuit is in the normal temperature range, the inclination of the increase in power consumption of the inverter circuit with respect to the increase in inverter output current per inverter circuit to be driven is small.
　また、このときの演算回路ＯＣによる、各インバータ回路の組合せパターンでの消費電力の演算結果は図７に示すようになる。演算回路ＯＣは、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２の駆動と停止の組合せにおけるそれぞれの合計消費電力Ｗｗ３を演算する。具体的には、演算回路ＯＣは、合計消費電力Ｗｗ３として、消費電力値Ｗｗ１１、Ｗｗ１２、Ｗｗ３３（Ｗｗ２１＋Ｗｗ２２）を演算する。 Further, the calculation result of the power consumption in the combination pattern of each inverter circuit by the arithmetic circuit OC at this time is as shown in FIG. The arithmetic circuit OC calculates the total power consumption Ww3 for each combination of driving and stopping of the first inverter circuit INV1 and the second inverter circuit INV2. Specifically, the arithmetic circuit OC calculates the power consumption values Ww11, Ww12, and Ww33 (Ww21 + Ww22) as the total power consumption Ww3.
　第１のインバータ回路ＩＮＶ１または第２のインバータ回路ＩＮＶ２のいずれか１個を駆動して出力端子ＯＴに平均出力電流Ｉｗを供給する場合のインバータ出力電流をインバータ出力電流Ｉ１とする。また、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２との２個のインバータ回路を共に駆動して出力端子ＯＴに平均出力電流Ｉｗを供給する場合のインバータ回路１個あたりのインバータ出力電流をインバータ出力電流Ｉ２とする。ここで、インバータ出力電流Ｉ１はインバータ出力電流Ｉ２よりも大きいという関係がある。また、２個のインバータ回路を共に駆動する場合、各インバータ回路の出力を同じとする。言い換えるとインバータ出力電流Ｉ１はインバータ出力電流Ｉ２の約２倍という関係となる。 The inverter output current when driving either one of the first inverter circuit INV1 or the second inverter circuit INV2 and supplying the average output current Iw to the output terminal OT is defined as an inverter output current I1. Further, the inverter output current per inverter circuit when the two inverter circuits of the first inverter circuit INV1 and the second inverter circuit INV2 are driven together to supply the average output current Iw to the output terminal OT is obtained. It is assumed that the inverter output current I2. Here, there is a relationship that the inverter output current I1 is larger than the inverter output current I2. When driving two inverter circuits together, the output of each inverter circuit is the same. In other words, the inverter output current I1 has a relationship of about twice the inverter output current I2.
　消費電力値Ｗｗ１１は、第１のインバータ回路ＩＮＶ１が駆動し、第２のインバータ回路ＩＮＶ２が停止した時の合計消費電力の値、すなわち、第１のインバータ回路ＩＮＶ１が１個だけ駆動したときの合計消費電力の値である。また、消費電力値Ｗｗ１２は、第１のインバータ回路ＩＮＶ１が停止し、第２のインバータ回路ＩＮＶ２が駆動した時の合計消費電力の値、すなわち、第２のインバータ回路ＩＮＶ２が１個だけ駆動したときの合計消費電力の値である。消費電力値Ｗｗ１１、消費電力値Ｗｗ１２で駆動する時のインバータ回路１個あたりのインバータ出力電流は、インバータ出力電流Ｉ１である。 The power consumption value Ww11 is the total power consumption when the first inverter circuit INV1 is driven and the second inverter circuit INV2 is stopped, that is, the total when only one first inverter circuit INV1 is driven. This is the power consumption value. The power consumption value Ww12 is the total power consumption when the first inverter circuit INV1 is stopped and the second inverter circuit INV2 is driven, that is, when only one second inverter circuit INV2 is driven. Is the value of the total power consumption. The inverter output current per inverter circuit when driving with the power consumption value Ww11 and the power consumption value Ww12 is the inverter output current I1.
　また、消費電力値Ｗｗ３３は、インバータ回路が２個共に駆動した時の各インバータ回路の消費電力値の和の消費電力の値である。すなわち、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２とが共に駆動した時の、第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ２１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ２２の和の消費電力の値である。消費電力値Ｗｗ２１、消費電力値Ｗｗ２２で駆動する時のインバータ回路１個あたりのインバータ出力電流は、インバータ出力電流Ｉ２である。 The power consumption value Ww33 is a power consumption value that is the sum of the power consumption values of the inverter circuits when both of the inverter circuits are driven. That is, the consumption of the sum of the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2 when both the first inverter circuit INV1 and the second inverter circuit INV2 are driven. This is the power value. The inverter output current per inverter circuit when driving with the power consumption value Ww21 and the power consumption value Ww22 is the inverter output current I2.
　具体的には、インバータ出力電流Ｉ１は、第１のインバータ回路ＩＮＶ１または第２のインバータ回路ＩＮＶ２のいずれか１個のインバータ回路を駆動して出力端子ＯＴに平均出力電流Ｉｗの電流を供給するときの、駆動しているインバータ回路のインバータ出力電流である。 Specifically, when the inverter output current I1 drives either one of the first inverter circuit INV1 or the second inverter circuit INV2 and supplies the average output current Iw to the output terminal OT. The inverter output current of the driving inverter circuit.
　第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ１１は、第１のインバータ回路ＩＮＶ１のみで出力端子ＯＴに平均出力電流Ｉｗの電流を供給したときの第１のインバータ回路ＩＮＶ１の消費電力の値である。 The power consumption value Ww11 of the first inverter circuit INV1 is the power consumption value of the first inverter circuit INV1 when the current of the average output current Iw is supplied to the output terminal OT only by the first inverter circuit INV1.
　第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ１２は、第２のインバータ回路ＩＮＶ２のみで出力端子ＯＴに平均出力電流Ｉｗの電流を供給したときの第２のインバータ回路ＩＮＶ２の消費電力の値である。なお、上述の条件においては、第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ１１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ１２はほぼ等しくなる。 The power consumption value Ww12 of the second inverter circuit INV2 is the power consumption value of the second inverter circuit INV2 when the current of the average output current Iw is supplied to the output terminal OT only by the second inverter circuit INV2. Note that, under the above-described conditions, the power consumption value Ww11 of the first inverter circuit INV1 and the power consumption value Ww12 of the second inverter circuit INV2 are substantially equal.
　また、インバータ出力電流Ｉ２は、２個のインバータ回路を共に駆動して出力端子ＯＴに平均出力電流Ｉｗの電流を供給するときの、インバータ回路１個あたりのインバータ出力電流である。第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ２１は、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２からなる２個のインバータ回路で出力端子ＯＴに平均出力電流Ｉｗの電流を供給したときの第１のインバータ回路ＩＮＶ１の消費電力の値である。 Further, the inverter output current I2 is an inverter output current per inverter circuit when the two inverter circuits are driven together to supply the average output current Iw to the output terminal OT. The power consumption value Ww21 of the first inverter circuit INV1 is the same as that when the average output current Iw is supplied to the output terminal OT by two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. 1 is a value of power consumption of one inverter circuit INV1.
　また、第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ２２は、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２からなる２個のインバータ回路で出力端子ＯＴに平均出力電流Ｉｗの電流を供給したときの第２のインバータ回路ＩＮＶ２の消費電力の値である。なお、上述の条件においては、第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ２１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ２２は、ほぼ等しくなる。 Further, the power consumption value Ww22 of the second inverter circuit INV2 is obtained when the current of the average output current Iw is supplied to the output terminal OT by the two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. This is the power consumption value of the second inverter circuit INV2. Note that, under the above-described conditions, the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2 are substantially equal.
　消費電力値Ｗｗ３３は、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２からなる２個のインバータ回路で出力端子ＯＴに平均出力電流Ｉｗの電流を共に供給したときの２個のインバータ回路の合計の消費電力である。その値は第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ２１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ２２の和である。 The power consumption value Ww33 is the sum of the two inverter circuits when the current of the average output current Iw is supplied to the output terminal OT by the two inverter circuits including the first inverter circuit INV1 and the second inverter circuit INV2. Power consumption. The value is the sum of the power consumption value Ww21 of the first inverter circuit INV1 and the power consumption value Ww22 of the second inverter circuit INV2.
　ここで、各インバータ回路の駆動と停止の組合せに対する演算回路ＯＣの演算結果の合計消費電力Ｗｗ３は、図７に示すようになる。かつ、スイッチング素子の温度が低い常温領域においてのインバータ回路の消費電力は、図６Ａに示すようになる。この場合において、例えば短絡溶接時のインバータ回路の消費電力が少なくなるインバータ回路の動作の組合せについては以下の様になる。 Here, the total power consumption Ww3 of the calculation result of the calculation circuit OC for the combination of driving and stopping of each inverter circuit is as shown in FIG. And the power consumption of the inverter circuit in the normal temperature region where the temperature of the switching element is low is as shown in FIG. 6A. In this case, for example, a combination of operation of the inverter circuit that reduces the power consumption of the inverter circuit during short-circuit welding is as follows.
　具体的には、消費電力値Ｗｗ３３は、消費電力値Ｗｗ１１よりも大きくなり、消費電力値Ｗｗ１２よりも大きくなる。 Specifically, the power consumption value Ww33 is larger than the power consumption value Ww11 and larger than the power consumption value Ww12.
　このため、選択回路ＳＣは、アーク加工用電源装置の消費電力が少なくなるように、常温領域では１個のインバータ回路を選択し、平均出力電流Ｉｗを出力端子ＯＴに供給するための選択信号Ｓｃを出力する。 For this reason, the selection circuit SC selects one inverter circuit in the room temperature region so that the power consumption of the arc machining power supply device is reduced, and the selection signal Sc for supplying the average output current Iw to the output terminal OT. Is output.
　この例では、第１の温度測定値Ｔ１と第２の温度測定値Ｔ２がほぼ等しいと仮定している。そのため、いずれか１個のインバータ回路が単独でのみ駆動する場合では、第１のインバータ回路ＩＮＶ１の消費電力値Ｗｗ１１と第２のインバータ回路ＩＮＶ２の消費電力値Ｗｗ１２はほぼ等しくなる。ただし、実際はどちらか小さい方のインバータ回路を駆動させるように選択信号Ｓｃが出力される。 In this example, it is assumed that the first temperature measurement value T1 and the second temperature measurement value T2 are substantially equal. Therefore, when any one inverter circuit is driven alone, the power consumption value Ww11 of the first inverter circuit INV1 and the power consumption value Ww12 of the second inverter circuit INV2 are substantially equal. However, the selection signal Sc is actually output so as to drive the smaller inverter circuit.
　その結果、インバータ回路のスイッチング素子の温度が低い常温領域において、短絡溶接時におけるインバータ出力電流と出力電圧と駆動するインバータ回路の個数の関係は、図８のようになる。本溶接期間Ｔｗと溶接終了期間Ｔｅでは、それぞれ１個のインバータ回路が駆動される。なお、溶接開始期間Ｔｈでは、出力電流閾値Ｉｔｈよりインバータ出力電流が大きくなるため２個のインバータ回路が駆動される。 As a result, in the normal temperature region where the temperature of the switching element of the inverter circuit is low, the relationship between the inverter output current and output voltage during short-circuit welding and the number of inverter circuits to be driven is as shown in FIG. In the main welding period Tw and the welding end period Te, one inverter circuit is driven. In the welding start period Th, the inverter output current becomes larger than the output current threshold value Ith, so that two inverter circuits are driven.
　また例えば、本溶接期間Ｔｗ等で１個のインバータ回路を駆動させた後、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２を構成するスイッチング素子の温度が同様に上昇し、高温領域となるとする。図３Ａに示すスイッチング素子の特性の場合、スイッチング素子の温度が上昇し高温領域となれば、駆動するインバータ回路１個あたりの出力電流に対する消費電力の増加傾きが大きくなり、言い換えると増加率が大きくなる。 Further, for example, after driving one inverter circuit in the main welding period Tw or the like, the temperature of the switching elements constituting the first inverter circuit INV1 and the second inverter circuit INV2 rises in the same manner, and becomes a high temperature region. To do. In the case of the characteristics of the switching element shown in FIG. 3A, when the temperature of the switching element rises and becomes a high temperature region, the increasing slope of power consumption with respect to the output current per driven inverter circuit increases, in other words, the increase rate increases. Become.
　このように、インバータ回路のスイッチング素子の温度が高い高温領域となり、駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力の関係が図３Ａに示すように、常温領域に比べて高温領域の方が消費電力の増加傾きが大きくなる。この場合、高温領域における１個当たりのインバータ回路のインバータ出力電流とインバータ回路の消費電力の関係は、図６Ｂに示すようになる。 Thus, the temperature of the switching element of the inverter circuit becomes a high temperature region, and the relationship between the inverter output current per inverter circuit to be driven and the power consumption of the inverter circuit is higher than that in the normal temperature region as shown in FIG. 3A. The increase slope of power consumption becomes larger in the region. In this case, the relationship between the inverter output current of each inverter circuit in the high temperature region and the power consumption of the inverter circuit is as shown in FIG. 6B.
　具体的には、第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２において、いずれかが駆動した時の消費電力値を消費電力値（Ｗｗ１１、Ｗｗ１２）とする。また、インバータ回路が２個共に駆動した時の、それぞれの消費電力値（Ｗｗ２１、Ｗｗ２２）の和である消費電力値を消費電力値Ｗｗ３３とする。図６Ｂに示すように、駆動するインバータ回路１個あたりのインバータ出力電流に対するインバータ回路の消費電力の増加傾きは、図６Ａに示す常温領域の関係に比べて大きい。 Specifically, the power consumption value when one of the first inverter circuit INV1 and the second inverter circuit INV2 is driven is the power consumption value (Ww11, Ww12). Further, the power consumption value that is the sum of the power consumption values (Ww21, Ww22) when the two inverter circuits are both driven is defined as a power consumption value Ww33. As shown in FIG. 6B, the increase slope of the power consumption of the inverter circuit with respect to the inverter output current per one inverter circuit to be driven is larger than the relationship in the normal temperature region shown in FIG. 6A.
　高温領域において、各インバータ回路の駆動と停止の組合せのパターンに対する演算回路ＯＣの演算結果の合計消費電力Ｗｗ３は、図７に示すようになる。インバータ回路の組み合わせ自体は、温度が上昇する前の常温領域から変化がない。スイッチング素子の温度が高くなる高温領域においてのインバータ回路の消費電力が図６Ｂに示す関係にある場合において、例えば短絡溶接時のインバータ回路の消費電力が少なくなるインバータ回路の動作の組合せについては以下の様になる。 In the high temperature region, the total power consumption Ww3 of the calculation result of the calculation circuit OC for the combination of driving and stopping of each inverter circuit is as shown in FIG. The inverter circuit combination itself does not change from the normal temperature region before the temperature rises. When the power consumption of the inverter circuit in the high temperature region where the temperature of the switching element is high is in the relationship shown in FIG. 6B, for example, the following combinations of operation of the inverter circuit that reduce the power consumption of the inverter circuit during short-circuit welding It becomes like.
　具体的には消費電力値Ｗｗ３３が、消費電力値Ｗｗ１１または消費電力値Ｗｗ１２よりも小さくなる。 Specifically, the power consumption value Ww33 is smaller than the power consumption value Ww11 or the power consumption value Ww12.
　このため、選択回路ＳＣは、アーク加工用電源装置の消費電力が少なくなるように、２個のインバータ回路を共に駆動させて平均出力電流Ｉｗを出力端子ＯＴに供給するための選択信号Ｓｃを出力する。 For this reason, the selection circuit SC outputs the selection signal Sc for driving the two inverter circuits together and supplying the average output current Iw to the output terminal OT so that the power consumption of the arc machining power supply device is reduced. To do.
　その結果、温度が上昇した高温領域において溶接を再開するような場合、短絡溶接時における出力電流と出力電圧と駆動するインバータ回路の個数の関係は例えば、図９に示すようになる。スイッチング素子の温度が上昇している本溶接期間Ｔｗと溶接終了期間Ｔｅでは２個のインバータ回路が駆動される。なお、溶接開始期間Ｔｈでは、出力電流閾値Ｉｔｈよりインバータ出力電流が大きくなるため２個のインバータ回路が駆動される。 As a result, when welding is resumed in a high temperature region where the temperature has risen, the relationship between the output current and output voltage during short-circuit welding and the number of inverter circuits to be driven is as shown in FIG. In the main welding period Tw and the welding end period Te in which the temperature of the switching element is rising, two inverter circuits are driven. In the welding start period Th, the inverter output current becomes larger than the output current threshold value Ith, so that two inverter circuits are driven.
　このように、本実施の形態のアーク加工用電源装置は、複数並列に設けられたインバータ回路（ＩＮＶ１、ＩＮＶ２）を含み、被加工物Ｍに対して短絡溶接を行う。短絡溶接は溶接開始期間Ｔｈ、本溶接期間Ｔｗ、および溶接終了期間Ｔｅを有する。短絡溶接の本溶接期間Ｔｗについては、アーク加工用電源装置は、インバータ回路（ＩＮＶ１、ＩＮＶ２）を構成するスイッチング素子の温度測定値（Ｔ１、Ｔ２）と被加工物Ｍに対して出力される溶接電流としての出力電流の時間平均である平均出力電流Ｉｗとからそれぞれのインバータ回路（ＩＮＶ１、ＩＮＶ２）の駆動と停止の動作の組合せにおける消費電力を演算する。また、アーク加工用電源装置は、複数のインバータ回路（ＩＮＶ１、ＩＮＶ２）における消費電力の合計である合計消費電力Ｗｗ３が最も小さくなるように、複数のインバータ回路それぞれの駆動と停止を選択する。 As described above, the arc machining power supply device of the present embodiment includes a plurality of inverter circuits (INV1, INV2) provided in parallel, and performs short-circuit welding on the workpiece M. The short-circuit welding has a welding start period Th, a main welding period Tw, and a welding end period Te. For the main welding period Tw of the short-circuit welding, the arc machining power supply apparatus outputs the measured temperature values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2) and the workpiece M to be welded. From the average output current Iw which is the time average of the output current as a current, the power consumption in the combination of the driving and stopping operations of the respective inverter circuits (INV1, INV2) is calculated. The arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits (INV1, INV2), is minimized.
　これにより、短絡溶接の本溶接期間Ｔｗにおける、アーク加工用電源装置を構成するインバータ回路（ＩＮＶ１、ＩＮＶ２）の消費電力を低減できる。 Thereby, the power consumption of the inverter circuits (INV1, INV2) constituting the arc machining power supply device during the main welding period Tw of the short-circuit welding can be reduced.
　（実施の形態２）
　次に、本開示の実施の形態２について、図１から図３Ａ、および、図１０から図１１を用いて説明をする。 (Embodiment 2)
Next, Embodiment 2 of the present disclosure will be described with reference to FIGS. 1 to 3A and FIGS. 10 to 11.
　実施の形態２のアーク加工用電源装置の構成は実施の形態１と同様である。図１に示す構成のアーク加工用電源装置において、第１の記憶回路ＭＣ１は、図２に示すインバータ出力電流に対する駆動が必要なインバータ回路の最少の個数の関係を記憶している。第２の記憶回路ＭＣ２は、図３Ａに示すインバータ回路を構成するスイッチング素子の温度と駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力の関係を記憶している。第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２が同じスイッチング素子で構成されている。図１０から図１１を用いて、パルス溶接の動作を説明する。パルス溶接は、ベース期間Ｔｂとピーク期間Ｔｐとを繰り返す本溶接期間を含む。アーク加工用電源装置は、ベース期間Ｔｂでは出力電流値が低いベース電流Ｉｂを出力し、ピーク期間Ｔｐでは出力電流値が高いピーク電流Ｉｐを出力する。 The configuration of the arc machining power supply device of the second embodiment is the same as that of the first embodiment. In the arc machining power supply device shown in FIG. 1, the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the inverter output current shown in FIG. The second memory circuit MC2 stores the relationship between the temperature of the switching elements constituting the inverter circuit shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit. The first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation of pulse welding will be described with reference to FIGS. Pulse welding includes a main welding period in which a base period Tb and a peak period Tp are repeated. The arc machining power supply device outputs a base current Ib having a low output current value in the base period Tb, and outputs a peak current Ip having a high output current value in the peak period Tp.
　図１０は、パルス溶接時の出力電流波形と出力電圧波形を示している。同図において、図５に示す短絡溶接時の出力電流波形と出力電圧波形を同一符号のものは、同一の意味を表すので説明は省略し、符号の相違するものについてのみ説明する。 FIG. 10 shows an output current waveform and an output voltage waveform during pulse welding. In the same figure, the output current waveform and the output voltage waveform at the time of short-circuit welding shown in FIG. 5 having the same reference sign represent the same meaning, and therefore description thereof will be omitted, and only the parts having different reference numerals will be described.
　パルス溶接では本溶接期間Ｔｗにおいて、出力電流値が低いベース期間Ｔｂと出力電流値が高いピーク期間Ｔｐが規則的かつ交互に存在している。ベース電流Ｉｂはベース期間Ｔｂでの出力電流値を表し、ピーク電流Ｉｐはピーク期間Ｔｐでの出力電流値を表している。 In pulse welding, a base period Tb with a low output current value and a peak period Tp with a high output current value regularly and alternately exist in the main welding period Tw. The base current Ib represents the output current value in the base period Tb, and the peak current Ip represents the output current value in the peak period Tp.
　一般的に、アーク加工用電源装置は、作業者により設定された平均出力電流Ｉｗに基づいて、ある演算を行い、ベース電流Ｉｂとピーク電流Ｉｐとを決定する。ただし、より溶接性を向上させるため、作業者が直接、ベース電流Ｉｂとピーク電流Ｉｐを調整することもできる。 Generally, the arc machining power supply apparatus performs a certain calculation based on the average output current Iw set by the operator, and determines the base current Ib and the peak current Ip. However, in order to further improve the weldability, the operator can directly adjust the base current Ib and the peak current Ip.
　パルス溶接は、短絡溶接と比べて、溶接ワイヤと被加工物Ｍとの接触（短絡）が少ない。ベース期間Ｔｂでは、出力電流と出力電圧がともに低く、ピーク期間Ｔｐでは、出力電流と出力電圧がともに高くなっている。そのため、ベース期間Ｔｂでは小さい電力で済ませられるが、ピーク期間Ｔｐでは大きな電力が必要となる。パルス溶接では、本溶接期間において出力電力は大きく変動する。 Pulse welding has less contact (short circuit) between the welding wire and the workpiece M than short circuit welding. In the base period Tb, both the output current and the output voltage are low, and in the peak period Tp, both the output current and the output voltage are high. For this reason, a small amount of power can be used in the base period Tb, but a large amount of power is required in the peak period Tp. In pulse welding, the output power varies greatly during the main welding period.
　そこで、パルス溶接における本溶接期間Ｔｗについては、ベース期間Ｔｂではベース電流Ｉｂの値が出力電流設定信号Ｉｓの設定値として扱われ、ピーク期間Ｔｐではピーク電流Ｉｐの値が出力電流設定信号Ｉｓの設定値として扱われる。 Therefore, for the main welding period Tw in pulse welding, the value of the base current Ib is handled as the set value of the output current setting signal Is in the base period Tb, and the value of the peak current Ip is set to the value of the output current setting signal Is in the peak period Tp. Treated as a setting value.
　本実施形態では、第１の記憶回路ＭＣ１に記憶されているパルス溶接の出力電流閾値Ｉｔｈとベース電流Ｉｂとピーク電流Ｉｐの関係が図１０、図１１に示すようになっている。大きな電力を必要とするピーク電流Ｉｐのピーク期間Ｔｐでは、比較信号Ｃｃは２個のインバータ回路の駆動を示す。そのため、アーク加工用電源装置は、２個のインバータ回路を駆動してピーク電流Ｉｐを出力する。 In this embodiment, the relationship between the output current threshold Ith, the base current Ib, and the peak current Ip of pulse welding stored in the first memory circuit MC1 is as shown in FIGS. In the peak period Tp of the peak current Ip that requires a large amount of power, the comparison signal Cc indicates driving of two inverter circuits. Therefore, the arc machining power supply device drives the two inverter circuits to output the peak current Ip.
　また、ピーク期間Ｔｐに比べて小さい電力を必要とするベース期間Ｔｂでは、比較信号Ｃｃは少なくとも１個のインバータ回路の駆動を示す。また、実施の形態１で説明したように、第１の温度測定値Ｔ１と第２の温度測定値Ｔ２による温度と、この温度に対する消費電力との関係によって第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２の駆動または停止が選択される。アーク加工用電源装置は、１個または２個のインバータ回路を駆動してベース電流Ｉｂを出力する。 Also, in the base period Tb that requires less power than the peak period Tp, the comparison signal Cc indicates driving of at least one inverter circuit. In addition, as described in the first embodiment, the first inverter circuit INV1 and the second temperature are determined by the relationship between the temperature based on the first temperature measurement value T1 and the second temperature measurement value T2 and the power consumption with respect to this temperature. Driving or stopping of the inverter circuit INV2 is selected. The arc machining power supply device drives one or two inverter circuits to output a base current Ib.
　図１１を用いて、パルス溶接における出力電流と出力電圧と、駆動するインバータ回路の個数の関係の一例を具体的に説明する。同図は、１回目から３回目までのベース期間Ｔｂでは１個のインバータが駆動され、４回目のベース期間Ｔｂでは２個のインバータが駆動された例を示す。時間の経過に伴って、インバータ回路を構成するスイッチング素子の温度が上昇する。上述の通り、スイッチング素子の温度が高温領域の場合、２個のインバータ回路を駆動したほうが１個のインバータ回路を駆動するよりも合計の消費電力が小さいことがある。図１１の例では、１回目から３回目までのベース期間Ｔｂでは、演算回路ＯＣは、１個のインバータ回路を駆動したほうが２個のインバータ回路を駆動するよりも消費電力を小さくできると判断する。そのため、選択回路ＳＣは、１個のインバータ回路の駆動を選択している。これに対して、４回目のベース期間Ｔｂにおいて、演算回路ＯＣは、１個のインバータ回路で駆動するよりも２個のインバータ回路で駆動したほうが、消費電力が小さいと判断する。そのため選択回路ＳＣは、２個のインバータ回路の駆動を選択している。 An example of the relationship between the output current and output voltage in pulse welding and the number of inverter circuits to be driven will be specifically described with reference to FIG. The figure shows an example in which one inverter is driven in the first to third base periods Tb and two inverters are driven in the fourth base period Tb. As time elapses, the temperature of the switching elements constituting the inverter circuit increases. As described above, when the temperature of the switching element is in a high temperature region, the total power consumption may be smaller when two inverter circuits are driven than when one inverter circuit is driven. In the example of FIG. 11, in the base period Tb from the first time to the third time, the arithmetic circuit OC determines that driving one inverter circuit can reduce power consumption compared to driving two inverter circuits. . For this reason, the selection circuit SC selects driving of one inverter circuit. In contrast, in the fourth base period Tb, the arithmetic circuit OC determines that the power consumption is smaller when driven by two inverter circuits than when driven by one inverter circuit. Therefore, the selection circuit SC selects driving of the two inverter circuits.
　このように、本実施の形態のアーク加工用電源装置は、複数並列に設けられたインバータ回路を含み、被加工物Ｍに対してパルス溶接を行う。パルス溶接は溶接開始期間Ｔｈ、本溶接期間Ｔｗ、および溶接終了期間Ｔｅを有する。パルス溶接の本溶接期間Ｔｗについては、アーク加工用電源装置は、インバータ回路（ＩＮＶ１、ＩＮＶ２）を構成するスイッチング素子の温度測定値（Ｔ１、Ｔ２）とパルス溶接のベース電流とピーク電流からそれぞれのインバータ回路（ＩＮＶ１、ＩＮＶ２）の駆動と停止の動作の組合せにおける消費電力を演算する。また、アーク加工用電源装置は、複数のインバータ回路（ＩＮＶ１、ＩＮＶ２）における消費電力の合計が最も小さくなるように複数のインバータ回路それぞれの駆動と停止を選択する。 Thus, the arc machining power supply device according to the present embodiment includes a plurality of inverter circuits provided in parallel and performs pulse welding on the workpiece M. Pulse welding has a welding start period Th, a main welding period Tw, and a welding end period Te. For the main welding period Tw of pulse welding, the power supply device for arc machining uses the measured temperature values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2), the base current and the peak current of the pulse welding, respectively. The power consumption in the combination of driving and stopping operations of the inverter circuits (INV1, INV2) is calculated. The arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption in the plurality of inverter circuits (INV1, INV2) is minimized.
　これにより、パルス溶接の本溶接期間Ｔｗにおける、アーク加工用電源装置を構成するインバータ回路（ＩＮＶ１、ＩＮＶ２）の消費電力を低減できる。 Thereby, the power consumption of the inverter circuits (INV1, INV2) constituting the arc machining power supply device during the main welding period Tw of the pulse welding can be reduced.
　（実施の形態３）
　次に、本開示の実施の形態３について、図１から図３Ａ、図５、および、図８から図１１を用いて説明をする。 (Embodiment 3)
Next, Embodiment 3 of the present disclosure will be described with reference to FIGS. 1 to 3A, FIG. 5, and FIGS. 8 to 11.
　実施の形態３のアーク加工用電源装置の構成は実施の形態１と同様である。図１に示す構成のアーク加工用電源装置において、第１の記憶回路ＭＣ１は図２に示すような出力電流に対する駆動が必要なインバータ回路の最少の個数の関係を記憶している。第２の記憶回路ＭＣ２は図３Ａに示すようなインバータ回路を構成するスイッチング素子の温度と駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力の関係を記憶している。第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２が同じスイッチング素子で構成されている。図５、図１０および図１１を用いて溶接開始期間の動作を説明する。 The configuration of the arc machining power supply device of the third embodiment is the same as that of the first embodiment. In the arc machining power supply device shown in FIG. 1, the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current as shown in FIG. The second memory circuit MC2 stores the relationship between the temperature of the switching element constituting the inverter circuit as shown in FIG. 3A, the inverter output current per one inverter circuit to be driven, and the power consumption of the inverter circuit. The first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation in the welding start period will be described with reference to FIGS.
　図５、図１０からわかるように、短絡溶接、および、パルス溶接のどちらにおいても、溶接開始期間Ｔｈでは、本溶接期間の平均出力電流Ｉｗよりも高い開始電流Ｉｈを一定時間出力するという、溶接を開始しやすくする処理を行っている。 As can be seen from FIGS. 5 and 10, in both short-circuit welding and pulse welding, in the welding start period Th, a start current Ih higher than the average output current Iw in the main welding period is output for a certain period of time. To make it easier to start.
　一般的に、アーク加工用電源装置は、作業者により設定された平均出力電流Ｉｗに基づいて、所定の演算を行い、開始電流Ｉｈを決定する。ただし、より溶接性を向上させるため、作業者が直接、開始電流Ｉｈを調整することもできる。 Generally, the arc machining power supply device performs a predetermined calculation on the basis of the average output current Iw set by the operator to determine the start current Ih. However, in order to further improve the weldability, the operator can directly adjust the starting current Ih.
　そこで、溶接開始期間Ｔｈについては、開始電流Ｉｈの値が出力電流設定信号Ｉｓの設定値として扱われる。 Therefore, for the welding start period Th, the value of the start current Ih is treated as the set value of the output current setting signal Is.
　開始電流Ｉｈが出力電流閾値Ｉｔｈよりも高い場合は、比較信号Ｃｃは２個のインバータ回路の駆動を示す。そのため、図８、図９、および図１１に示すように、アーク加工用電源装置は、２個のインバータ回路を駆動して開始電流Ｉｈを出力する。 When the start current Ih is higher than the output current threshold Ith, the comparison signal Cc indicates driving of two inverter circuits. Therefore, as shown in FIGS. 8, 9, and 11, the arc machining power supply device drives two inverter circuits to output a start current Ih.
　このように、本実施の形態のアーク加工用電源装置は溶接開始期間Ｔｈについては、インバータ回路（ＩＮＶ１、ＩＮＶ２）を構成するスイッチング素子の温度測定値（Ｔ１、Ｔ２）と、本溶接期間Ｔｗにおける、一定の開始電流Ｉｈとからそれぞれのインバータ回路（ＩＮＶ１、ＩＮＶ２）での消費電力を演算する。また、アーク加工用電源装置は、複数のインバータ回路での消費電力の合計である合計消費電力Ｗｗ３が最も小さくなるようにインバータ回路（ＩＮＶ１、ＩＮＶ２）の駆動と停止を選択する。一定の開始電流Ｉｈは、平均出力電流Ｉｗよりも高くてもよい。 As described above, in the arc machining power supply device of the present embodiment, for the welding start period Th, the temperature measurement values (T1, T2) of the switching elements constituting the inverter circuit (INV1, INV2) and the main welding period Tw are used. The power consumption in each inverter circuit (INV1, INV2) is calculated from the constant start current Ih. The arc machining power supply device selects driving and stopping of the inverter circuits (INV1, INV2) so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits, is minimized. The constant start current Ih may be higher than the average output current Iw.
　なお、インバータ回路（ＩＮＶ１、ＩＮＶ２）での消費電力を演算するために用いる開始電流Ｉｈは、一定の開始電流Ｉｈとしたが、平均開始電流Ｉｈｗとしても良い。この平均開始電流Ｉｈｗは、溶接開始期間Ｔｈにおける出力電流を時間平均した電流である。平均開始電流Ｉｈｗは、平均出力電流Ｉｗよりも高くてもよい。 Note that the start current Ih used to calculate the power consumption in the inverter circuits (INV1, INV2) is a constant start current Ih, but may be an average start current Ihw. The average start current Ihw is a current obtained by averaging the output current in the welding start period Th. The average start current Ihw may be higher than the average output current Iw.
　これにより、溶接開始期間Ｔｈにおける、アーク加工用電源装置を構成するインバータ回路（ＩＮＶ１、ＩＮＶ２）における消費電力を低減できる。 Thereby, power consumption in the inverter circuits (INV1, INV2) constituting the power supply device for arc machining in the welding start period Th can be reduced.
　（実施の形態４）
　次に、本開示の実施の形態４について、図１から図３Ａ、図５、および、図８から図１１を用いて説明をする。 (Embodiment 4)
Next, a fourth embodiment of the present disclosure will be described with reference to FIGS. 1 to 3A, FIG. 5, and FIGS. 8 to 11.
　実施の形態４のアーク加工用電源装置の構成は実施の形態１と同様である。図１に示す構成のアーク加工用電源装置において、第１の記憶回路ＭＣ１は図２に示すような出力電流に対する駆動が必要なインバータ回路の最少の個数の関係を記憶している。第２の記憶回路ＭＣ２は図３Ａに示すようなインバータ回路を構成するスイッチング素子の温度とインバータ回路１個あたりの出力電流とインバータ回路の消費電力の関係を記憶している。第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２が同じスイッチング素子で構成されている。図５、図１０および図１１を用いて溶接終了期間の動作を説明する。 The configuration of the arc machining power supply device of the fourth embodiment is the same as that of the first embodiment. In the arc machining power supply device shown in FIG. 1, the first memory circuit MC1 stores the relationship of the minimum number of inverter circuits that need to be driven with respect to the output current as shown in FIG. The second memory circuit MC2 stores the relationship among the temperature of the switching elements constituting the inverter circuit as shown in FIG. 3A, the output current per inverter circuit, and the power consumption of the inverter circuit. The first inverter circuit INV1 and the second inverter circuit INV2 are composed of the same switching element. The operation in the welding end period will be described with reference to FIGS. 5, 10, and 11.
　短絡溶接、および、パルス溶接のどちらにおいても、図５、図１０からわかるように溶接終了期間Ｔｅでは、本溶接期間の平均出力電流Ｉｗよりも低い終端電流Ｉｅを一定時間出力するという、溶接ワイヤと被加工物Ｍがくっついてしまうのを防ぐ処理を行っている。 In both the short-circuit welding and the pulse welding, as can be seen from FIGS. 5 and 10, in the welding end period Te, a welding current that outputs a terminal current Ie lower than the average output current Iw in the main welding period for a certain period of time. And processing to prevent the workpiece M from sticking to each other.
　一般的に、アーク加工用電源装置は、作業者により設定された平均出力電流Ｉｗに基づいて、所定の演算を行い、終端電流Ｉｅを決定する。ただし、より溶接性を向上させるため、作業者が直接、終端電流Ｉｅを調整することもできる。 Generally, the arc machining power supply device performs a predetermined calculation on the basis of the average output current Iw set by the operator to determine the termination current Ie. However, in order to further improve the weldability, the operator can also adjust the termination current Ie directly.
　そこで、溶接終了期間Ｔｅについては、終端電流Ｉｅの値が出力電流設定信号Ｉｓの設定値として扱われる。 Therefore, for the welding end period Te, the value of the termination current Ie is treated as the set value of the output current setting signal Is.
　終端電流Ｉｅが出力電流閾値Ｉｔｈよりも低い場合は、比較信号Ｃｃは少なくとも１個のインバータ回路の駆動を示す。実施の形態１で説明したように、アーク加工用電源装置は、インバータ回路の温度と消費電力の関係に基づき、第１の温度測定値Ｔ１と第２の温度測定値Ｔ２によって第１のインバータ回路ＩＮＶ１と第２のインバータ回路ＩＮＶ２の駆動または停止を選択する。アーク加工用電源装置は、選択されたインバータ回路を駆動して終端電流Ｉｅを出力する。図８、図１１は１個のインバータ回路で終端電流Ｉｅを出力している例を示す。また、図９は２個のインバータ回路で終端電流Ｉｅを出力している例を示す。 When the termination current Ie is lower than the output current threshold Ith, the comparison signal Cc indicates driving of at least one inverter circuit. As described in the first embodiment, the arc machining power supply device uses the first temperature measurement value T1 and the second temperature measurement value T2 based on the relationship between the temperature of the inverter circuit and the power consumption. The driving or stopping of INV1 and the second inverter circuit INV2 is selected. The arc machining power supply device drives the selected inverter circuit to output the termination current Ie. 8 and 11 show examples in which the termination current Ie is output by one inverter circuit. FIG. 9 shows an example in which the termination current Ie is output by two inverter circuits.
　このように、本実施の形態のアーク加工用電源装置は溶接終了期間Ｔｅについては、インバータ回路（ＩＮＶ１、ＩＮＶ２）を構成するスイッチング素子の温度測定値（Ｔ１、Ｔ２）と、一定の終端電流Ｉｅとからそれぞれのインバータ回路（ＩＮＶ１、ＩＮＶ２）の動作の組合せにおける消費電力を演算する。また、アーク加工用電源装置は、複数のインバータ回路（ＩＮＶ１、ＩＮＶ２）での消費電力の合計である合計消費電力Ｗｗ３が最も小さくなるように複数のインバータ回路それぞれの駆動と停止を選択する。一定の終端電流Ｉｅは、平均出力電流Ｉｗよりも低くてもよい。なお、インバータ回路（ＩＮＶ１、ＩＮＶ２）での消費電力を演算するために用いる終端電流Ｉｅは、平均出力電流Ｉｗよりも低い一定の終端電流Ｉｅとしたが、平均出力電流Ｉｗよりも低い平均終端電流Ｉｅｗとしても良い。この平均終端電流Ｉｅｗは、溶接終了期間Ｔｅにおける出力電流を時間平均した電流である。平均終端電流Ｉｅｗは、平均出力電流Ｉｗよりも低くてもよい。 As described above, in the arc machining power supply device according to the present embodiment, for the welding end period Te, the temperature measurement values (T1, T2) of the switching elements constituting the inverter circuits (INV1, INV2) and the constant termination current Ie. The power consumption in the combination of operations of the respective inverter circuits (INV1, INV2) is calculated from the above. The arc machining power supply device selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption Ww3, which is the total power consumption of the plurality of inverter circuits (INV1, INV2), is minimized. The constant termination current Ie may be lower than the average output current Iw. The termination current Ie used for calculating the power consumption in the inverter circuits (INV1, INV2) is a constant termination current Ie lower than the average output current Iw, but the average termination current Ie is lower than the average output current Iw. It may be Iew. This average terminal current Iew is a current obtained by averaging the output current in the welding end period Te. The average termination current Iew may be lower than the average output current Iw.
　これにより、溶接終了期間Ｔｅにおける、アーク加工用電源装置を構成するインバータ回路（ＩＮＶ１、ＩＮＶ２）における消費電力を低減できる。 Thus, power consumption in the inverter circuits (INV1, INV2) constituting the arc machining power supply device during the welding end period Te can be reduced.
　以上、実施の形態１から実施の形態４で詳述したように本開示の技術は、溶接方法や溶接期間によって、適切な出力電流設定信号Ｉｓを予め設定しておくことで、消費電力の低減が図れる。また、実施の形態１から実施の形態４までの何れかの組み合わせによっては、溶接開始期間、本開始期間および溶接終了期間を含む全溶接期間において消費電力を低減できる。 As described above in detail in Embodiments 1 to 4, the technology of the present disclosure reduces power consumption by setting an appropriate output current setting signal Is in advance depending on the welding method and the welding period. Can be planned. Further, depending on any combination of the first to fourth embodiments, the power consumption can be reduced in the entire welding period including the welding start period, the main start period, and the welding end period.
　本開示に係るアーク加工用電源装置は、インバータ回路を構成するスイッチング素子の温度の測定値と出力電流に係る設定値によって、複数あるインバータ回路の駆動または停止を、インバータ回路での消費電力が小さくなるように選択できるため、産業上有用である。 In the arc machining power supply device according to the present disclosure, a plurality of inverter circuits are driven or stopped according to a measured value of a temperature of a switching element constituting the inverter circuit and a set value related to an output current, and power consumption in the inverter circuit is reduced. Since it can be selected, it is industrially useful.
　ＡＣ　商用交流電源
　Ｃ１　第１の平滑コンデンサ
　Ｃ２　第２の平滑コンデンサ
　ＣＣ　比較回路
　Ｃｃ　比較信号
　ＣＴ　出力電流検出回路
　ＤＣＬ　直流リアクトル
　ＤＲ１１　第１の１次整流回路
　ＤＲ１２　第２の１次整流回路
　ＤＲ２１　第１の２次整流回路
　ＤＲ２２　第２の２次整流回路
　Ｉ１、Ｉ２　インバータ出力電流
　Ｉｂ　ベース電流
　Ｉｅ　終端電流
　Ｉｅｗ　平均終端電流
　Ｉｈ　開始電流
　Ｉｈｗ　平均開始電流
　ＩＮＶ１　第１のインバータ回路
　ＩＮＶ２　第２のインバータ回路
　Ｉｏ　出力電流検出信号
　Ｉｐ　ピーク電流
　ＩＳ　出力電流設定回路
　Ｉｓ　出力電流設定信号
　Ｉｔｈ　出力電流閾値
　Ｉｗ　平均出力電流
　Ｍ　被加工物
　ＭＣ１　第１の記憶回路
　Ｍｃ１　第１の記憶信号
　ＭＣ２　第２の記憶回路
　Ｍｃ２　第２の記憶信号
　ＭＴＲ１　第１の主変圧器
　ＭＴＲ２　第２の主変圧器
　ＯＣ　演算回路
　Ｏｃ　演算信号
　ＯＣＣ　出力制御回路
　Ｏｃｃ１　第１の出力制御信号
　Ｏｃｃ２　第２の出力制御信号
　ＯＴ　出力端子
　ＳＣ　選択回路
　Ｓｃ　選択信号
　ＳＤ１　第１のインバータ駆動回路
　Ｓｄ１　第１のインバータ駆動信号
　ＳＤ２　第２のインバータ駆動回路
　Ｓｄ２　第２のインバータ駆動信号
　Ｔ１　第１の温度測定値
　Ｔ２　第２の温度測定値
　Ｔａ　アーク期間
　Ｔｂ　ベース期間
　Ｔｅ　溶接終了期間
　ＴＨ　トーチ
　Ｔｈ　溶接開始期間
　Ｔｐ　ピーク期間
　Ｔｓ　短絡期間
　Ｔｗ　本溶接期間
　Ｗ２１、Ｗ２２、Ｗ３１、Ｗ３２、Ｗ４３　消費電力値
　Ｗｗ１１、Ｗｗ１２、Ｗｗ２１、Ｗｗ２２、Ｗｗ３３　消費電力値
　Ｗｗ３　合計消費電力 AC commercial AC power supply C1 first smoothing capacitor C2 second smoothing capacitor CC comparison circuit Cc comparison signal CT output current detection circuit DCL DC reactor DR11 first primary rectification circuit DR12 second primary rectification circuit DR21 first Secondary rectifier circuit DR22 Second secondary rectifier circuit I1, I2 Inverter output current Ib Base current Ie Termination current Iew Average termination current Ih Start current Ihw Average start current INV1 First inverter circuit INV2 Second inverter circuit Io Output current Detection signal Ip Peak current IS Output current setting circuit Is Output current setting signal Ith Output current threshold Iw Average output current M Work piece MC1 First storage circuit Mc1 First storage signal MC2 Second storage circuit Mc2 Second storage Signal MTR1 First main transformer MTR2 Second Transformer OC arithmetic circuit Oc arithmetic signal OCC output control circuit Occ1 first output control signal Occ2 second output control signal OT output terminal SC selection circuit Sc selection signal SD1 first inverter drive circuit Sd1 first inverter drive signal SD2 Second inverter drive circuit Sd2 Second inverter drive signal T1 First temperature measurement value T2 Second temperature measurement value Ta arc period Tb base period Te welding end period TH torch Th welding start period Tp peak period Ts short circuit period Tw Main welding period W21, W22, W31, W32, W43 Power consumption value Ww11, Ww12, Ww21, Ww22, Ww33 Power consumption value Ww3 Total power consumption

Claims (9)

  1. 被溶接物に対して短絡溶接またはパルス溶接を行うアーク加工用電源装置であって、
    商用交流電力を整流し直流電圧を出力する第１の１次整流回路と、
    前記第１の１次整流回路から出力された直流電圧を平滑する第１の平滑コンデンサと、
    前記第１の平滑コンデンサで平滑された直流電圧を高周波交流電圧に変換する第１のインバータ回路と、
    前記第１のインバータ回路の出力をアーク加工に適した高周波交流電圧に変換する第１の主変圧器と、
    前記第１の主変圧器の出力を整流する第１の２次整流回路と、
    前記商用交流電力を整流し直流電圧を出力する第２の１次整流回路と、
    前記第２の１次整流回路から出力された直流電圧を平滑する第２の平滑コンデンサと、
    前記第２の平滑コンデンサで平滑された直流電圧を高周波交流電圧に変換する第２のインバータ回路と、
    前記第２のインバータ回路の出力をアーク加工に適した高周波交流電圧に変換する第２の主変圧器と、
    前記第２の主変圧器の出力を整流する第２の２次整流回路と、
    前記第１の２次整流回路の出力と前記第２の２次整流回路の出力を合わせた電流を平滑して出力端子に出力電流を出力する直流リアクトルと、
    前記出力電流の検出を行う出力電流検出回路と、
    予め定めた出力電流に係る設定値を設定する出力電流設定回路と、
    出力電流に対応する駆動が必要なインバータ回路の最少の個数を予め記憶する第１の記憶回路と、
    前記出力電流設定回路によって設定された出力電流に係る設定値と前記第１の記憶回路に記憶されている出力電流に対応する駆動が必要なインバータ回路の最少の個数とを比較して、前記設定に対応する駆動が必要なインバータ回路の最少の個数を求める比較回路と、
    インバータ回路を構成するスイッチング素子の温度と駆動するインバータ回路１個あたりのインバータ出力電流とインバータ回路の消費電力との関係である温度に対する消費電力の関係を予め記憶する第２の記憶回路と、前記出力電流設定回路によって設定された出力電流に係る設定値と、
    前記第１のインバータ回路を構成するスイッチング素子の測定された温度と、前記第２のインバータ回路を構成するスイッチング素子の測定された温度と、前記第２の記憶回路の記憶されている前記温度に対する消費電力の関係から、各インバータ回路の駆動と停止の組合せに対する消費電力を求める演算回路と、
    前記比較回路より求めた前記設定に対応する駆動が必要なインバータ回路の最少の個数以上で、前記演算回路で求めた消費電力の中で最も消費電力が小さくなるインバータ回路の組合せを選択する選択回路と、
    前記選択回路により選択されたインバータ回路の組合せに基づいて、前記第１のインバータ回路を制御する第１の出力制御信号と前記第２のインバータ回路を制御する第２の出力制御信号を出力する出力制御回路と、を備えるアーク加工用電源装置。     A power supply device for arc processing that performs short-circuit welding or pulse welding on a workpiece,
    A first primary rectifier circuit that rectifies commercial AC power and outputs a DC voltage;
    A first smoothing capacitor for smoothing a DC voltage output from the first primary rectifier circuit;
    A first inverter circuit for converting a DC voltage smoothed by the first smoothing capacitor into a high-frequency AC voltage;
    A first main transformer for converting the output of the first inverter circuit into a high-frequency AC voltage suitable for arc machining;
    A first secondary rectifier circuit for rectifying the output of the first main transformer;
    A second primary rectifier circuit that rectifies the commercial AC power and outputs a DC voltage;
    A second smoothing capacitor for smoothing the DC voltage output from the second primary rectifier circuit;
    A second inverter circuit for converting a DC voltage smoothed by the second smoothing capacitor into a high-frequency AC voltage;
    A second main transformer for converting the output of the second inverter circuit into a high-frequency AC voltage suitable for arc machining;
    A second secondary rectifier circuit for rectifying the output of the second main transformer;
    A DC reactor for smoothing a current obtained by combining the output of the first secondary rectifier circuit and the output of the second secondary rectifier circuit and outputting an output current to an output terminal;
    An output current detection circuit for detecting the output current;
    An output current setting circuit for setting a set value related to a predetermined output current;
    A first storage circuit that stores in advance a minimum number of inverter circuits that need to be driven according to the output current;
    The setting value related to the output current set by the output current setting circuit is compared with the minimum number of inverter circuits that require driving corresponding to the output current stored in the first storage circuit, and the setting is performed. A comparison circuit for obtaining the minimum number of inverter circuits that need to be driven corresponding to
    A second storage circuit for storing in advance a relationship of power consumption with respect to temperature, which is a relationship between the temperature of the switching elements constituting the inverter circuit and the inverter output current per inverter circuit to be driven and the power consumption of the inverter circuit; A set value related to the output current set by the output current setting circuit;
    With respect to the measured temperature of the switching element that constitutes the first inverter circuit, the measured temperature of the switching element that constitutes the second inverter circuit, and the temperature stored in the second storage circuit From the relationship of power consumption, an arithmetic circuit for obtaining power consumption for a combination of driving and stopping of each inverter circuit,
    A selection circuit that selects a combination of inverter circuits having the smallest power consumption among the power consumptions obtained by the arithmetic circuit, with a minimum number of inverter circuits that need to be driven corresponding to the setting obtained from the comparison circuit. When,
    An output for outputting a first output control signal for controlling the first inverter circuit and a second output control signal for controlling the second inverter circuit based on a combination of the inverter circuits selected by the selection circuit. An arc machining power supply device comprising a control circuit.
  2. 前記短絡溶接は、溶接開始期間、本溶接期間、および溶接終了期間を有し、前記本溶接期間については、前記被溶接物に対して出力される出力電流の時間平均である平均出力電流を出力電流に係る設定値とする請求項１記載のアーク加工用電源装置。 The short-circuit welding has a welding start period, a main welding period, and a welding end period. For the main welding period, an average output current that is a time average of the output current output to the workpiece is output. The arc machining power supply device according to claim 1, wherein the power supply device is a set value related to an electric current.
  3. 前記パルス溶接は、溶接開始期間、本溶接期間、および溶接終了期間を有し、前記本溶接期間については、ベース電流値とピーク電流値を出力電流に係る設定値とする請求項１記載のアーク加工用電源装置。 The arc according to claim 1, wherein the pulse welding has a welding start period, a main welding period, and a welding end period, and for the main welding period, a base current value and a peak current value are set values related to an output current. Power supply for processing.
  4. 前記溶接開始期間については、溶接を開始する溶接開始電流値を出力電流に係る設定値とする請求項２または３記載のアーク加工用電源装置。 4. The arc machining power supply device according to claim 2, wherein a welding start current value for starting welding is a set value related to an output current for the welding start period. 5.
  5. 前記溶接終了期間については、溶接の終了に用いられる溶接終端電流値を出力電流に係る設定値とする請求項２または３記載のアーク加工用電源装置。 4. The arc machining power supply device according to claim 2, wherein for the welding end period, a welding end current value used for the end of welding is set to a set value related to an output current.
  6. インバータ回路が複数並列に設けられ、被溶接物に対して、溶接開始期間、本溶接期間、および溶接終了期間を有する短絡溶接を行うアーク加工用電源装置の制御方法であって、
    前記短絡溶接の前記本溶接期間については、前記インバータ回路を構成するスイッチング素子の温度の測定値と、前記被溶接物に対して出力される出力電流の時間平均である平均出力電流とからそれぞれの前記インバータ回路の動作の組合せにおける消費電力を演算し、
    複数の前記インバータ回路での消費電力の合計が最も小さくなるように複数の前記インバータ回路それぞれの駆動と停止を選択するアーク加工用電源装置の制御方法。     A control method of a power supply device for arc processing, in which a plurality of inverter circuits are provided in parallel, and short-circuit welding having a welding start period, a main welding period, and a welding end period is performed on a workpiece.
    For the main welding period of the short-circuit welding, each of the measured value of the temperature of the switching element constituting the inverter circuit and the average output current that is the time average of the output current output to the workpiece is Calculate power consumption in the combination of operation of the inverter circuit,
    A control method for an arc machining power supply apparatus that selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption of the plurality of inverter circuits is minimized.
  7. インバータ回路が複数並列に設けられ、被溶接物に対して、溶接開始期間、本溶接期間、および溶接終了期間を有するパルス溶接を行うアーク加工用電源装置の制御方法であって、
    前記パルス溶接の前記本溶接期間については、前記インバータ回路を構成するスイッチング素子の温度の測定値と前記パルス溶接のベース電流およびピーク電流とからそれぞれの前記インバータ回路の動作の組合せにおける消費電力を演算し、
    複数の前記インバータ回路での消費電力の合計が最も小さくなるように複数の前記インバータ回路それぞれの駆動と停止を選択するアーク加工用電源装置の制御方法。     A control method for a power supply device for arc machining, in which a plurality of inverter circuits are provided in parallel and performing pulse welding having a welding start period, a main welding period, and a welding end period on an object to be welded,
    For the main welding period of the pulse welding, the power consumption in the combination of the operation of the inverter circuit is calculated from the measured value of the temperature of the switching element constituting the inverter circuit and the base current and peak current of the pulse welding. And
    A control method for an arc machining power supply apparatus that selects driving and stopping of each of the plurality of inverter circuits so that the total power consumption of the plurality of inverter circuits is minimized.
  8. 前記溶接開始期間については、前記インバータ回路を構成するスイッチング素子の温度の測定値と、一定の開始電流または溶接開始期間における出力電流を時間平均した平均開始電流とからそれぞれの前記インバータ回路の動作の組合せにおける消費電力を演算し、
    複数の前記インバータ回路での消費電力の合計が最も小さくなるように複数の前記インバータ回路それぞれの駆動と停止を選択する請求項６または７に記載のアーク加工用電源装置の制御方法。     With respect to the welding start period, the operation of each inverter circuit is determined from the measured value of the temperature of the switching element constituting the inverter circuit and the average start current obtained by averaging the constant start current or the output current in the welding start period. Calculate power consumption in combination,
    The method for controlling an arc machining power supply device according to claim 6 or 7, wherein driving and stopping of each of the plurality of inverter circuits are selected so that the total power consumption of the plurality of inverter circuits is minimized.
  9. 前記溶接終了期間については、前記インバータ回路を構成するスイッチング素子の温度の測定値と、一定の終端電流または溶接終了期間における出力電流を時間平均した平均終端電流とからそれぞれの前記インバータ回路の動作の組合せにおける消費電力を演算し、
    複数の前記インバータ回路での消費電力の合計が最も小さくなるように複数の前記インバータ回路それぞれの駆動と停止を選択する請求項６または７に記載のアーク加工用電源装置の制御方法。     For the welding end period, the operation of each inverter circuit is measured from the measured value of the temperature of the switching elements constituting the inverter circuit and the average termination current obtained by averaging the constant termination current or the output current in the welding termination period. Calculate power consumption in combination,
    The method for controlling an arc machining power supply device according to claim 6 or 7, wherein driving and stopping of each of the plurality of inverter circuits are selected so that the total power consumption of the plurality of inverter circuits is minimized.
PCT/JP2018/008926 2017-05-29 2018-03-08 Power supply device for arc processing and method for controlling power supply device for arc processing WO2018220933A1 (en)

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