JP6498457B2 - Power supply device and power supply device for welding - Google Patents

Description

  The present invention relates to a power supply device and a welding power supply device.

  For example, a power supply device used for an arc welder generates a welding current for a welding target, for example, based on commercial AC power. The power supply device smoothes DC power converted from commercial AC power by a primary rectifier using a smoothing capacitor, and converts the DC power into high-frequency AC power using an inverter circuit. Furthermore, a power supply device produces | generates a welding current with a high frequency alternating current power by a transformer and a secondary rectifier.

  In such a power supply device, a rated output current value and a rated usage rate are determined (see, for example, Patent Document 1). The control device of the power supply device limits the use of the power supply device (output current or a period during which current is output) based on the rated usage rate. This suppresses a decrease in durability due to heat generation of a transistor or the like included in a transformer or an inverter circuit.

JP 11-259149 A

  By the way, for example, an electrolytic capacitor is used as the smoothing capacitor of the power supply device as described above. The temperature of the smoothing capacitor rises depending on the operating state of the power supply device. And the temperature rise of a smoothing capacitor causes the capacity | capacitance fall of the smoothing capacitor, and there exists a possibility of affecting weldability.

  The present invention has been made to solve the above-described problems, and an object thereof is to suppress an increase in temperature of the smoothing capacitor.

A power supply apparatus that solves the above problems includes a DC power supply circuit that rectifies commercial AC power and outputs a DC voltage, a voltage conversion circuit that has a smoothing capacitor and converts the DC voltage, and an output of the voltage conversion circuit An inverter circuit that converts a voltage into a high-frequency AC voltage, a transformer that converts the high-frequency AC voltage into an AC voltage, a rectifier circuit that rectifies the output of the transformer to generate a DC output, and detects an output current A current detection circuit; a voltage detection circuit that detects an output voltage; a control circuit that controls the inverter circuit so that the value of the output current is equal to a current setting value; and whether the commercial AC power is three-phase or single-phase And an input determination circuit that outputs a determination signal, and the control circuit sets a rated current and a rated usage rate according to the commercial AC power based on the determination signal, and the rated power And the calculated equivalent power continuously output based on the rated utilization the output current and the output voltage of the based on the value load power is compared with the equivalent power, the said load power based on the comparison result equivalent If it is greater than the power, the inverter circuit is stopped.

  According to this configuration, the control circuit calculates the equivalent power for continuous use based on the rated current and the rated usage rate according to the three-phase or single-phase commercial AC power. Then, the control circuit compares the load power based on the output current and the output voltage with the equivalent power, and stops the inverter circuit according to the comparison result, for example, when the load power exceeds the equivalent power. The internal temperature of the power supply device decreases due to the stop of the inverter circuit. For this reason, the temperature rise of the smoothing capacitor included in the voltage conversion circuit is suppressed.

Power supply to solve the above SL problem, a DC power supply circuit that outputs a DC voltage by rectifying the commercial AC power, having a smoothing capacitor, a voltage conversion circuit for voltage conversion of the DC voltage, of the voltage conversion circuit An inverter circuit that converts an output voltage into a high-frequency AC voltage, a transformer that converts the high-frequency AC voltage into an AC voltage, a rectifier circuit that rectifies the output of the transformer to generate a DC output, and detects an output current A current detecting circuit for detecting the output voltage, a voltage detecting circuit for detecting the output voltage, a control circuit for controlling the inverter circuit so that the value of the output current is equal to a current setting value, and the commercial AC power is three-phase or single-phase. An input determination circuit for determining whether or not the rated power is used, and the control circuit sets a rated current and a rated usage rate according to the commercial AC power based on the determination signal. And the equivalent power of the continuous output is calculated based on the rated usage rate, the load power based on the values of the output current and the output voltage is compared with the equivalent power, and the inverter circuit is stopped based on the comparison result The control circuit counts up a count value when the load power is greater than the equivalent power, counts down the count value when the load power is less than or equal to the equivalent power, and outputs the output current and The inverter circuit calculates an allowable usage rate based on the output voltage, compares a reference value corresponding to the allowable usage rate with the count value, and the inverter circuit when the count value is greater than or equal to the reference value based on a comparison result the stop.
According to this configuration, the control circuit calculates the equivalent power for continuous use based on the rated current and the rated usage rate according to the three-phase or single-phase commercial AC power. Then, the control circuit compares the load power based on the output current and the output voltage with the equivalent power, and stops the inverter circuit according to the comparison result, for example, when the load power exceeds the equivalent power. The internal temperature of the power supply device decreases due to the stop of the inverter circuit. For this reason, the temperature rise of the smoothing capacitor included in the voltage conversion circuit is suppressed.

  According to this configuration, the reference value corresponding to the allowable usage rate calculated based on the output power is compared with the count value, and the inverter circuit is stopped based on the comparison result. For this reason, the temperature rise of the smoothing capacitor due to the overload state and the overuse rate is suppressed.

  In the above power supply device, the control circuit calculates a calculation current value for calculating the allowable usage rate based on the output current and the output voltage, and calculates the calculation current value, the rated current, and the rating It is preferable to calculate the allowable usage rate based on the usage rate.

According to this configuration, the allowable usage rate is calculated according to the output current and the output voltage.
In the above power supply apparatus, the control circuit calculates an equivalent current with a usage rate of 100 (%) based on the rated current and the rated usage rate, calculates an equivalent voltage based on the equivalent current, and calculates the equivalent It is preferable to calculate the equivalent power based on the current and the equivalent voltage.
According to this configuration, the equivalent current when the usage rate is 100 (%) is calculated based on the rated current and the rated usage rate. Based on this equivalent current, an equivalent voltage and an equivalent power are calculated.
Moreover, the welding power supply device which solves the said subject is comprised so that the output electric current which processes a welding object may be produced | generated using said power supply device.

  According to this structure, the fall of the weldability with respect to a welding target is suppressed.

  According to the present invention, the temperature rise of the smoothing capacitor can be suppressed.

It is a block circuit diagram of an arc welder. (A) (b) is a characteristic view which shows an example of the relationship between output electric power and a utilization factor. It is a flowchart which shows the process of a control circuit.

Hereinafter, an embodiment will be described.
As shown in FIG. 1, the arc welding machine 10 has a welding power supply device (hereinafter simply referred to as a power supply device) 11. Three-phase or single-phase AC input power is supplied to the input terminals 12a, 12b, and 12c of the power supply device 11. The positive output terminal 13a of the power supply device 11 is connected to, for example, a welding torch TH, and the negative output terminal 13b of the power supply device 11 is connected to, for example, a welding target (base material) M.

  The power supply device 11 converts three-phase or single-phase AC input power into DC output power corresponding to a set value. This DC output power generates an arc between an electrode (for example, a welding wire) held on the welding torch TH and the welding target M. The welding object M is processed by the arc generated in this way.

  The DC power supply circuit 21 of the power supply device 11 is connected to three input terminals 12a, 12b, and 12c. Commercial AC power is supplied to the input terminals 12a, 12b, and 12c. Commercial AC power is three-phase or single-phase AC power. Three-phase (U-phase, V-phase, W-phase) AC power is supplied to the input terminals 12a, 12b, 12c. Single-phase AC power is supplied to the input terminals 12a and 12b.

The DC power supply circuit 21 of the power supply device 11 converts commercial AC power into DC power.
The DC power supply circuit 21 includes a rectifier circuit DR1, smoothing capacitors C1 and C2, and resistors R1 and R2. The rectifier circuit DR1 is, for example, a diode bridge circuit. The rectifier circuit DR1 has six diodes D1, D2, D3, D4, D5, and D6, and these diodes D1 to D6 are bridge-connected.

  Smoothing capacitors C1 and C2 are connected in series. Smoothing capacitors C1 and C2 are, for example, electrolytic capacitors. A resistor R1 is connected in parallel to the smoothing capacitor C1. A resistor R2 is connected in parallel to the smoothing capacitor C2. The resistors R1 and R2 are discharging resistors.

The output power of the DC power supply circuit 21 is supplied to the voltage conversion circuit 22.
The voltage conversion circuit 22 is, for example, a step-down chopper circuit 22 and includes a switching element TR2, a diode D11, a reactor DL1, a smoothing capacitor C3, a voltage detection circuit VD2, and a control circuit SC. Switching element TR2 is, for example, a bipolar transistor. Smoothing capacitor C3 is, for example, an electrolytic capacitor. The voltage detection circuit VD2 detects the output voltage of the voltage conversion circuit 22 and outputs a voltage detection signal Vd2. The control circuit SC generates a control signal Sc2 based on the voltage detection signal Vd2 output from the voltage detection circuit VD2. The switching element TR2 is turned on / off based on the control signal Sc2. Therefore, the control circuit SC controls the on / off of the switching element TR2, and sets the output voltage to a constant voltage.

  The inverter circuit 23 has a bridge circuit using a plurality of (for example, four) switching elements TR1. The switching element TR1 is, for example, an insulated gate bipolar transistor (IGBT). The inverter circuit 23 converts the output voltage of the voltage conversion circuit 22 into a high-frequency AC voltage by turning on and off the switching element TR1.

  The transformer 24 is a transformer having a primary coil and a secondary coil, for example. The transformer 24 generates a voltage corresponding to the winding ratio in the secondary coil based on the AC voltage output from the inverter circuit 23. Both terminals of the secondary coil are connected to the input terminal of the rectifier circuit 25, and the output terminal of the rectifier circuit 25 is connected to the first terminal of the DC reactor DCL. The second terminal of the DC reactor DCL is connected to the plus output terminal 13a. The center tap of the secondary coil of the transformer 24 is connected to the negative output terminal 13b. The rectifier circuit 25 rectifies the AC voltage generated by the transformer 24. The direct current reactor DCL smoothes the output voltage of the transformer 24.

  The voltage detection circuit VD1 detects a voltage (output voltage) Vo between the output terminals 13a and 13b, and outputs a voltage detection signal Vd1 corresponding to the output voltage Vo. The current detection circuit ID1 detects a current (welding current) Io flowing through the power supply line L1, and outputs a current detection signal Id1 corresponding to the welding current Io.

  The control circuit 27 generates a control signal Sc1 for the inverter circuit 23. The switching element TR1 of the inverter circuit 23 is turned on / off in response to the control signal Sc1. Based on the operation of the inverter circuit 23, the power supply device 11 generates an output voltage Vo and an output current Io corresponding to the set values.

  For example, the memory 27a of the control circuit 27 stores various set values. The set value includes a current set value. The control circuit 27 obtains the value of the output current Io based on the current detection signal Id1. The control circuit 27 controls the inverter circuit 23 so that the value of the output current Io becomes equal to the current set value. Further, the set value of the memory 27a includes a voltage set value. The control circuit 27 obtains the value of the output voltage Vo based on the voltage detection signal Vd1. The control circuit 27 controls the inverter circuit 23 so that the value of the output voltage Vo becomes equal to the voltage setting value.

  The input determination circuit 26 determines whether the input power is three-phase power or single-phase power based on the input voltages Vv and Vw at the input terminals 12b and 12c, and outputs a determination signal Cd according to the determination result. For example, the input determination circuit 26 outputs a first level (for example, H level) determination signal Cd when the input power is determined as three-phase power, and the second level (when the input power is determined as single-phase power). For example, an L level determination signal Cd is output.

  For example, the input determination circuit 26 monitors the interphase voltage Vv-w at the input terminal 12b and the input terminal 12c. In the case of three-phase power, the interphase voltage Vv-w corresponds to the input power. On the other hand, in the case of single-phase power, the interphase voltage Vv-w is “0”. The input determination circuit 26 generates a voltage (for example, a rectified and smoothed voltage) obtained by dividing the interphase voltage Vv-w by a resistor or the like. The input determination circuit 26 sets a predetermined threshold value and compares the threshold value with the divided voltage value. When the divided voltage value is larger than the threshold value, the input determination circuit 26 determines that the input power is three-phase power and outputs a first level determination signal Cd. On the other hand, if the value of the divided voltage is smaller than the threshold value, the input determination circuit 26 determines that the input power is single-phase power and outputs a second level determination signal Cd.

  The memory 27a of the control circuit 27 stores various set values. Based on the determination signal Cd, the control circuit 27 reads a setting value corresponding to the three-phase input power or a setting value corresponding to the single-phase input power from the memory 27a. Then, the control circuit 27 generates a control signal Sc1 for the inverter circuit 23 based on the set value, the voltage detection signal Vd1, and the current detection signal Id1.

  The set values in the memory 27a include a rated current value Ir and a rated usage rate Dr in the arc welder 10. The rated current value Ir may be described as the rated current Ir. Similarly, other voltage values and current values may be simply described as current and voltage.

  The rated current Ir and the rated usage rate Dr are set according to the input power. That is, the memory 27a stores the rated current Ir and the rated usage rate Dr corresponding to the three-phase input power, and the rated current Ir and the rated usage rate Dr corresponding to the single-phase input power. Based on the determination signal Cd, the control circuit 27 reads the rated current Ir and the rated usage rate Dr corresponding to the three-phase input power, or the rated current Ir and the rated usage rate Dr corresponding to the single-phase input power from the memory 27a. For example, the rated current Ir corresponding to three-phase input power is 350 (A), and the rated usage rate Dr is 60 (%). The rated current Ir corresponding to the single-phase input power is 250 (A), and the rated usage rate Dr is 60 (%).

The set value of the memory 27a includes constants A and B in the arc welder 10. The constants A and B are set according to the welding machine. For example, in the case of a carbon dioxide (CO ₂ ) welder, the constant A is “14” and the constant B is “0.05”.

  A characteristic curve L11 shown in FIG. 2A shows the characteristic of the rated power Wr (= rated current Ir × rated voltage Vr) with respect to the usage rate when the input power is three-phase AC power. In FIG. 2A, 60 (%) is the rated usage rate Dr at the three-phase input power. A characteristic curve L12 shown in FIG. 2B shows the characteristic of the rated power Wr with respect to the usage rate when the input power is single-phase AC power. In FIG. 2B, 60 (%) is the rated usage rate Dr at single-phase input power.

  As shown in FIG. 1, a notification device 29 is connected to the control circuit 27. The notification device 29 is a device capable of reporting the state of the power supply device 11 to the outside (for example, an operator). As the notification device 29, for example, a display such as an LCD, an indicator lamp, a buzzer, or the like can be used.

FIG. 3 shows a flowchart for protection control in the control circuit 27. When the power supply device 11 is activated, initialization is performed and processing of each step shown in FIG. 3 is executed.
In the initial setting, the control circuit 27 performs setting at the time of starting the power supply device 11 (performs initial setting). In this initial setting, the control circuit 27 reads the rated current Ir and the rated usage rate Dr corresponding to the input power from the memory 27a based on the determination signal Cd of the input determination circuit 26 described above. Then, the control circuit 27 calculates an equivalent current I ₁₀₀ and an equivalent voltage V ₁₀₀ based on the rated current Ir and the rated usage rate Dr.

The equivalent current I ₁₀₀ is the maximum current amount among the current values at which the power supply device 11 can be used continuously, that is, the allowable usage rate is 100%.
The allowable usage rate Dp for the set value of the output current Io is Ia.

Is calculated by Therefore, the control circuit 27
The equivalent current I _{100 at} which the allowable usage rate is 100 (%) is

Calculated by Then, the control circuit 27 generates the equivalent voltage V ₁₀₀ based on the equivalent current I ₁₀₀ .

Calculated by
Further, the control circuit 27 clears the count value N (N = 0).
In step 51, the control circuit 27 obtains a value obtained by measuring the output current Io based on the current detection signal Id1. This value is defined as a measurement current Io. Further, the control circuit 27 obtains a value obtained by measuring the output voltage Vo based on the voltage detection signal Vd1. This value is defined as a measurement voltage Vo.

  The measurement current Io is a sufficiently smoothed value. For example, the control circuit 27 has a low-pass filter (for example, a cut-off frequency of about 1 to 10 Hz), and thereby obtains a measured current Io by sampling a signal obtained by smoothing the current detection signal Id1. The measurement voltage Vo is a sufficiently smoothed value. For example, the control circuit 27 has a low-pass filter (for example, a cut-off frequency of about 1 to 10 Hz), and thereby obtains a measurement voltage Vo by sampling a signal obtained by smoothing the voltage detection signal Vd1.

  Note that, for example, a value obtained as a result of a moving average of digital values obtained by sampling the current detection signal Id1 at a predetermined sampling period (for example, 10 μs) may be used as the measurement current Io. Similarly, the measurement voltage Vo may be a value obtained as a result of a moving average of digital values obtained by sampling the voltage detection signal Vd1 at a predetermined sampling period (for example, 10 μs).

Then, the control circuit 27 compares the measured power Wo (= Io × Vo) with the equivalent power W ₁₀₀ (= I ₁₀₀ × V ₁₀₀ ). When the measured power Wo is equal to or less than the equivalent power W ₁₀₀ (Wo (= Io × Vo) ≦ W ₁₀₀ (= I ₁₀₀ × V ₁₀₀ )), the control circuit 27 proceeds to Step 53. On the other hand, the measured power Wo is greater than the equivalent power _{W 100,} the routine proceeds to step 52.

In step 52, the control circuit 27 counts up the count value N, that is, increases the count value N by “1”. Then, the control circuit 27 proceeds to step 56.
In step 53, the control circuit 27 counts down the count value N, that is, decreases the count value N by “1”. In step 54, the control circuit 27 compares the count value N with the value “0”. When the count value N is smaller than “0” (N <0), that is, when the count value N is a negative value, the control circuit 27 clears the count value N in step 55, that is, sets the count value N to “0”. Then, the process proceeds to step 56. On the other hand, if the count value N is greater than or equal to “0” in step 54, the process proceeds to step 56.

Next, in step 56, the control circuit 27 calculates the allowable usage rate Dp according to the measured power Wo (= measured current Io × measured voltage Vo).
First, the control circuit 27 calculates a calculation current value Ix necessary for calculating the allowable usage rate Dp based on the measurement current Io and the measurement voltage Vo. The control circuit 27 sets the calculation voltage value corresponding to the calculation current value Ix to Vx. This calculation voltage value Vx is calculated by calculating current value Ix and constants A and B.

It is expressed. The calculation current value Ix is calculated by the calculation voltage value Vx, the measurement current Io, the measurement voltage Vo, and the above formula.

It is expressed.
In this equation, when the calculation current value Ix is arranged,

It becomes. Thereby, the control circuit 27 calculates the calculation current value Ix.
Next, the control circuit 27 calculates the allowable usage rate Dp. The control circuit 27 determines the allowable usage rate Dp from the rated current Ir, the rated usage rate Dr, and the calculation current value Ix.

Calculated by
Next, in step 57, the control circuit 27 sets the reference value Nx according to the allowable usage rate Dp as described above.

Calculated by Then, the control circuit 27 compares the count value N with the reference value Nx. If the count value N is smaller than the reference value Nx (N <Nx), the control circuit 27 proceeds to step 51. On the other hand, if the count value N is greater than or equal to the reference value Nx (N ≧ Nx), the control circuit 27 proceeds to step 58.

In step 58, the control circuit 27 clears the count value N (N = 0).
Next, in step 59, the control circuit 27 stops the inverter circuit 23. Then, the control circuit 27 notifies the stop of the inverter circuit 23 by the notification device 29.

For example, the reference value Nx is set to a value equal to the count value N when continuously counted up in step 52 in the period corresponding to the allowable usage rate Dp.
The control circuit 27 executes the processing shown in FIG. 3 at a predetermined cycle (for example, every second). That is, the count value N is changed every predetermined cycle (1 second).

  Generally, the allowable usage rate Dp is calculated based on the rated current Ir and the rated usage rate Dr with respect to the set value Ia of the output current Io. The rated usage rate Dr indicates a ratio of a period in which the output of the rated current Ir is allowed in a predetermined period (for example, 10 minutes). Therefore, the allowable usage rate Dp indicates a ratio of a period during which output of the output current Io (set value Ia) is allowed in a predetermined period (for example, 10 minutes). In the power supply device used at the allowable usage rate Dp, the temperature of the internal components (inverter circuit 23, transformer 24, etc.) does not exceed the allowable temperature.

In step 51, when the measured power Wo (= measured current Io × measured voltage Vo) is larger than the equivalent power W ₁₀₀ (= equivalent current I ₁₀₀ × equivalent voltage V ₁₀₀ ), the power exceeding the rating flows through the load. If this state continues, the temperature of the components (for example, the smoothing capacitor C3, the inverter circuit 23, etc.) of the power supply device 11 shown in FIG. 1 may exceed the allowable temperature. For this reason, when the count value N becomes equal to or greater than the reference value Nx set according to the allowable usage rate Dp, the inverter circuit 23 is stopped (step 59), whereby the components of the power supply device 11 (for example, smoothing capacitors) C3 etc.) temperature rise is suppressed. Further, the control circuit 27 notifies the stop of the inverter circuit 23 by the notification device 29.

  In the present embodiment, the allowable usage rate Dp is calculated based on the measured power Wo (measured current Io, measured voltage Vo). As described in step 57 above, the allowable usage rate Dp is proportional to the reciprocal of the square of the calculation current value Ix calculated based on the measured power Wo (measured current Io, measured voltage Vo). Therefore, the smaller the measured power Wo, the larger the allowable usage rate Dp, that is, the value of the reference value Nx. Thus, setting the reference value Nx according to the measured power Wo (measured current Io, measured voltage Vo) enables the power supply device 11 to be used continuously. That is, a decrease in work efficiency due to the output power Wo of the power supply device 11 is suppressed. The reference value Nx limits the operation time of the inverter circuit 23. This is because the stop of the inverter circuit 23 causes the interruption of the work, increasing the number of man-hours and lowering the work efficiency.

Note that, based on the determination result of step 51, when the measured power Wo (= measured current Io × measured voltage Vo) is equal to or lower than the equivalent power W ₁₀₀ (= equivalent current I ₁₀₀ × equivalent voltage V ₁₀₀ ), the count is performed in step 53 Count down the value N. If the measured power Wo is equivalent power _{W 100} or less, the temperature of the components of the power supply device 11 is reduced. That is, the control circuit 27 changes the count value N according to the temperature change of the components of the power supply device 11.

Next, the operation of the power supply device 11 will be described.
The DC power supply circuit 21 of the power supply device 11 rectifies a three-phase or single-phase commercial AC current and outputs a DC voltage. The voltage conversion circuit 22 includes a smoothing capacitor C3 and converts the output voltage of the DC power supply circuit 21 into a voltage corresponding to the inverter circuit 23. The smoothing capacitor C3 smoothes the voltage after voltage conversion in the voltage conversion circuit 22. The inverter circuit 23 converts the output voltage of the voltage conversion circuit 22 into a high frequency AC voltage.

  The control circuit 27 of the power supply device 11 sets the rated current Ir and the rated usage rate Dr according to the three-phase or single-phase commercial AC power based on the determination signal Cd of the input determination circuit 26. The control circuit 27 controls the inverter circuit 23 so that the value of the output current Io is equal to the set current value.

  The rated current Ir and the rated usage rate Dr for the three-phase commercial AC power are, for example, 350 (A) and 60 (%). The output current value with respect to the rated current Ir is 31.5 (V). The rated current Ir and the rated usage rate Dr for single-phase commercial AC power are, for example, 250 (A) and 60 (%). The output current value with respect to the rated current Ir is 26.5 (V). Therefore, the load during operation based on single-phase commercial AC power is lower than the load during operation based on three-phase commercial AC power.

  The output current Io and the output voltage Vo in arc welding vary depending on work conditions (for example, the interval between the welding electrode and the welding target, the arc state, etc.). That is, the magnitude of the load changes. In the case of an overload, the internal temperature of the power supply device 11 exceeds the allowable temperature due to heat generation of components of the power supply device 11 (for example, the switching element TR1 of the inverter circuit 23). For example, a rise in temperature of the smoothing capacitor C3 included in the voltage conversion circuit 22 causes a reduction in the capacity of the smoothing capacitor C3, which may affect weldability.

  For example, it is conceivable to provide a thermostat or the like for the switching element or the like of the inverter circuit to achieve temperature protection. However, the above temperature protection is set according to the operation based on the three-phase commercial AC power with a large load. For this reason, at the time of the driving | running based on the single phase commercial alternating current power with a small load compared with three phases, protection by said thermostat etc. is difficult.

  In order to detect and protect the temperature of the smoothing capacitor with, for example, a thermocouple, a dedicated circuit corresponding to the thermocouple is required. Further, when the smoothing capacitor is protected by a thermostat, the thermostat must be fixed to the surface of the smoothing capacitor with silicon or the like, so that the temperature may not be detected accurately.

On the other hand, the control circuit 27 of the power supply device 11 in the present embodiment calculates the equivalent power W ₁₀₀ (equivalent current I ₁₀₀ , equivalent voltage V ₁₀₀ ) based on the current detection signal Id1 of the current detection circuit ID1. The control circuit 27 compares the output power Wo equivalent power _{W 100} based on the output current Io and an output voltage Vo (measured current Io and the measured voltage Vo). Then, the control circuit 27 based on the comparison result, the output power Wo is when exceeding the equivalent power _{W 100,} it stops the inverter circuit 23. Therefore, the output power Wo is at overload exceeding the equivalent power W _100, temperature rise of the smoothing capacitor C3 is suppressed.

For example, when the power supply device 11 is used exceeding the rated usage rate, the internal temperature of the power supply device 11 may similarly exceed the allowable temperature.
The control circuit 27 of the present embodiment, the output power Wo is counted up (+1) the count value N when exceeding the equivalent power _{W 100.} The control circuit 27 calculates the allowable usage rate Dp according to the output power Wo, and compares the reference value Nx and the count value N according to the allowable usage rate Dp. When the count value N is greater than or equal to the reference value Nx, the inverter circuit 23 is stopped.

  The temperature in the power supply device 11 (component temperature) changes slowly in time (for example, about 1 to 2 hours until temperature saturation). That is, even in an overload state, the internal temperature of the power supply device 11 does not immediately exceed the allowable temperature.

  The control circuit 27 sets a reference value Nx corresponding to the output power Wo, and compares the reference value Nx with the count value N. Then, the control circuit 27 stops the inverter circuit 23 when the count value N becomes equal to or greater than the reference value Nx, that is, when the overload state continues longer than the period corresponding to the allowable usage rate Dp, that is, when the usage rate is exceeded. .

Then, the control circuit 27, the output power Wo counts down (-1) the count value N at equivalent power _{W 100} or less. When the output power Wo is equal to or less than the equivalent power W ₁₀₀ , the temperature of the components of the power supply device 11 decreases. In the control that only counts up the count value N, the count value N exceeds the reference value Nx due to a cumulative overload, and the inverter circuit 23 may be stopped even when the temperature is low. When the inverter circuit 23 is stopped, the output of the power supply device 11 is stopped, so that the operation is interrupted. The interruption of work leads to an increase in man-hours and decreases production efficiency.

  On the other hand, the control circuit 27 of this embodiment counts down the count value N according to the temperature drop of the components of the power supply device 11, that is, changes the count value N according to the temperature change. Therefore, work interruption is suppressed.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The control circuit 27 calculates the equivalent power W ₁₀₀ for continuous use based on the rated current Ir and the rated usage rate Dr according to the three-phase or single-phase commercial AC power. Then, the control circuit 27 compares the output power Wo based on the output current Io and the output voltage Vo (measured current Io and the measured voltage Vo) and (load power) equivalent power _{W 100,} in accordance with the comparison result, for example, the output power Wo stops the inverter circuit 23 when exceeding the equivalent power _{W 100.} When the inverter circuit 23 is stopped, the temperature inside the power supply device 11 is lowered. For this reason, the temperature rise of the smoothing capacitor included in the voltage conversion circuit 22 can be suppressed.

(2) the control circuit 27, utilization based on the rated current Ir and rating usage Dr calculates the equivalent current _{I 100} 100 (%). Then, the control circuit 27 calculates an equivalent voltage V ₁₀₀ and an equivalent power W ₁₀₀ based on the equivalent current I ₁₀₀ . The equivalent power W ₁₀₀ is the maximum value of power that can be output by the power supply device 11 based on the rated current Ir and the rated usage rate Dr. Thus, the operation / stop of the inverter circuit 23 can be controlled in accordance with the equivalent power W ₁₀₀ corresponding to the input commercial AC power.

(3) control circuit 27, the output power Wo counts up the count value N when larger equivalent power _{W 100,} the output power Wo counts down the count value N at equivalent power _{W 100} or less. The control circuit 27 calculates the allowable usage rate Dp based on the output current Io and the output voltage Vo. Then, the control circuit 27 compares the reference value Nx corresponding to the allowable usage rate Dp with the count value N, and stops the inverter circuit 23 when the count value N is greater than or equal to the reference value Nx based on the comparison result. For this reason, it is possible to suppress an increase in the temperature of the smoothing capacitor due to an overload state and an overuse rate.

  (4) The control circuit 27 calculates a calculation current value Ix for calculating the allowable usage rate Dp based on the output current Io and the output voltage Vo, and calculates the calculation current value Ix, the rated current Ir, and the rated usage rate Dr. Based on the above, the allowable usage rate Dp is calculated. Thereby, the allowable usage rate Dp according to the output power Wo (output current Io, output voltage Vo) can be easily set.

In addition, you may implement each said embodiment in the following aspects.
In the above embodiment, set values such as the rated current Ir and the rated usage rate Dr are examples, and can be changed as appropriate.

The input determination circuit 26 is provided to determine whether the input power is single phase or three phase, and based on the determination result, the equivalent current I _{100 and the} like are calculated using the rated value according to the input power. In contrast, stored in for example memory 27a as the set value input power may be calculated equivalent current I ₁₀₀ or the like by using a rated value according to the setting value.

  In FIG. 1, the control circuits 27 and SC may be a single control circuit.

11 Power supply (Power supply for welding)
21 DC power supply circuit 22 Voltage conversion circuit 23 Inverter circuit 24 Transformer 25 Rectifier circuit 26 Input determination circuit 27 Control circuit ID1 Current detection circuit VD1 Voltage detection circuit C3 Smoothing capacitor Io Output current (measurement current)
Vo output voltage (measurement voltage)
Cd judgment signal Ir Rated current Dr Rated usage rate Wo Output power (load power)
W ₁₀₀ equivalent power

Claims (5)

A DC power supply circuit that rectifies commercial AC power and outputs a DC voltage;
A voltage conversion circuit having a smoothing capacitor and converting the DC voltage into a voltage;
An inverter circuit for converting the output voltage of the voltage conversion circuit into a high-frequency AC voltage;
A transformer for converting the high-frequency AC voltage into an AC voltage;
A rectifier circuit that rectifies the output of the transformer to generate a direct current output;
A current detection circuit for detecting the output current;
A voltage detection circuit for detecting the output voltage;
A control circuit for controlling the inverter circuit so that the value of the output current is equal to a current setting value;
An input determination circuit that determines whether the commercial AC power is three-phase or single-phase and outputs a determination signal;
Have
The control circuit sets a rated current and a rated usage rate according to the commercial AC power based on the determination signal, calculates an equivalent power of a continuous output based on the rated current and the rated usage rate, and outputs the output Comparing the load power based on the value of the current and the output voltage with the equivalent power, and if the load power is greater than the equivalent power based on the comparison result, stopping the inverter circuit;
A power supply characterized by. A DC power supply circuit that rectifies commercial AC power and outputs a DC voltage;
A voltage conversion circuit having a smoothing capacitor and converting the DC voltage into a voltage;
An inverter circuit for converting the output voltage of the voltage conversion circuit into a high-frequency AC voltage;
A transformer for converting the high-frequency AC voltage into an AC voltage;
A rectifier circuit that rectifies the output of the transformer to generate a direct current output;
A current detection circuit for detecting the output current;
A voltage detection circuit for detecting the output voltage;
A control circuit for controlling the inverter circuit so that the value of the output current is equal to a current setting value;
An input determination circuit that determines whether the commercial AC power is three-phase or single-phase and outputs a determination signal;
Have
The control circuit sets a rated current and a rated usage rate according to the commercial AC power based on the determination signal, calculates an equivalent power of a continuous output based on the rated current and the rated usage rate, and outputs the output Comparing the load power based on the value of the current and the output voltage and the equivalent power, and stopping the inverter circuit based on the comparison result,
The control circuit includes:
When the load power is greater than the equivalent power, the count value is counted up, and when the load power is less than or equal to the equivalent power, the count value is counted down, and an allowable usage rate is determined based on the output current and the output voltage. Calculating, comparing a reference value according to the allowable usage rate and the count value, and stopping the inverter circuit when the count value is equal to or greater than the reference value based on a comparison result;
A power supply characterized by. The power supply device according to claim 2 ,
The control circuit includes:
A calculation current value for calculating the allowable usage rate is calculated based on the output current and the output voltage, and the allowable usage rate is calculated based on the calculation current value, the rated current, and the rated usage rate. A power supply device characterized by calculating. The power supply device according to any one of claims 1 to 3 ,
The control circuit includes:
An equivalent current having a usage rate of 100 (%) is calculated based on the rated current and the rated usage rate, an equivalent voltage is calculated based on the equivalent current, and the equivalent power is calculated based on the equivalent current and the equivalent voltage. And calculating a power supply device.   The power supply device according to any one of claims 1 to 4, wherein the power supply device is configured to generate an output current for processing a welding target.