JP2694502B2 - Power supply for arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for arc welding, and in particular, rectifies and smoothes a commercial power supply voltage to generate a direct current voltage, and the direct current voltage has a frequency higher than that of the commercial power supply voltage by an inverter. The present invention relates to a converter-type power source for arc welding that converts the voltage into an AC voltage and outputs the AC voltage.

[0002]

2. Description of the Related Art A converter type power source for arc welding uses a commercial AC voltage of 50 Hz or 60 Hz for 20 k.
It is converted into an AC voltage having a high frequency of Hz to 50 kHz and outputted, and the transformer and the reactor are remarkably downsized as compared with the case where a commercial AC power supply voltage is used, and the power source apparatus for arc welding is downsized.

For example, FIG. 4 is a schematic circuit diagram of a main part of a converter-type power source for arc welding which has been conventionally used. A three-phase commercial power source voltage supplied to an input terminal 71 is rectified by a rectifier circuit 72. , And smoothed by the capacitor 73 to generate a DC voltage. This DC voltage is applied to the switching type inverter 70 by, for example, 20 kHz to 50 kHz.
Converted to AC voltage of Hz. The output of the inverter 70 is transformed by the transformer 87, is transformed and then rectified by the rectifier 88, and the output is output to the output terminal 89.

The inverter 70 is an IBG connected in series.
A first switching circuit 74 composed of T76 and 77;
A second pair of IGBTs 78 and 79, which are also connected in series
And the switching circuit 75. A drive signal from the drive device 80 is input to the control terminals of the switching elements 76 to 79, and the switching circuit operates in response to the drive signal.

The switching circuit 74 which constitutes the inverter 70 includes IGBTs 76,
77 is configured as a first module in a state of being insulated from the package substrate, and similarly, the switching circuit 75 is configured as a second module in a package in which each of the IGBTs 78 and 79 is insulated from the package substrate. Has been done.

The drive device 80 includes drive circuits 81 to 84 for outputting drive signals to the IGBTs 76 to 79, and the drive circuits 8 respectively.
A control circuit 85 for controlling 1 to 84 is provided. Each of the drive circuits 81 to 84 is composed of an insulating pulse transformer and electronic circuits such as resistors, capacitors, diodes, and ICs. In addition, in this drive device, drive circuits 81 to 84 and a control circuit 85 are mounted on one printed circuit board. Although the commercial power source is shown as a three-phase power source in FIG. 4, a single-phase commercial power source may be used. In addition, the switching circuit I that constitutes the inverter
As the GBT, a MOSFET or a bipolar transistor may be used in addition to the illustrated IGBT. further,
In the power supply device for arc welding of FIG. 4, a rectifier 88 is provided on the output side.
Is used as a DC power supply device.
Except for 8, it may be used as an AC power supply device.

[0007]

In the conventional arc welding power supply device of FIG. 4, the switching circuits 74 and 75 and the drive device 80 are separately arranged. Therefore, the drive circuit 81
~ 84 and the wiring between the IGBT76 ~ 79,
The high frequency noise is easily received, and the IGBTs 76 to 79 often malfunction. Therefore, the drive device 80 is wired near the switching circuits 74 and 75, and a special electric wire such as a coaxial wire or a twisted wire is used. Further, since the switching circuits 74 and 75 and the driving device 6 are separately arranged,
The space occupied by the power supply is large, and there is a limit to downsizing the power supply.

In particular, the power source for arc welding is usually determined by the usage rate for 10 minutes, but it may be used at a welding site under usage conditions other than the specified usage rate, and the temperature of the inverter may rise. There was also. Further, when an abnormality such as a stop of the cooling fan occurs, it is necessary to take measures such as stopping the power supply device.

[0009]

According to the present invention, a commercial power supply voltage is rectified and smoothed by a rectifier circuit and a smoothing capacitor to generate a DC voltage. This DC voltage is converted into an AC voltage having a frequency higher than the commercial power supply frequency by an inverter. A power semiconductor chip composed of a drive circuit for driving the inverter is mounted and fixed on a copper circuit laminated on one side of the upper surface of a metal substrate having an insulating layer, and the control parts constituting the drive circuit are fixed to a printed circuit board. , Or fixedly arranged on the copper circuit, when a temperature above a predetermined temperature in the vicinity of the power semiconductor chip, a temperature detection element for instructing the drive circuit to stop the inverter is mounted on the copper circuit, and further the semiconductor chip The control part is covered with a resin case, and the inside of the case is sealed with resin.

[0010]

According to the present invention, a power semiconductor chip that constitutes an inverter and a control component that constitutes a drive circuit are mounted and fixed on a copper circuit laminated on one side of an upper surface of a metal substrate having an insulating layer. Therefore, the distance between the switching circuit and the driving circuit can be designed to be short. Further, by fixing the control component forming the drive circuit to the printed circuit board and disposing the power semiconductor chip on the copper circuit by disposing the control component on the printed circuit board, the control component is mounted on the printed circuit board. It can be fixed separately. Further, a temperature detecting element is provided on the copper circuit to detect the temperature inside the case, and when the temperature is equal to or higher than a predetermined temperature, the inverter is commanded to stop.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a converter-type arc welding power supply device of the present invention, which is electrically similar to the conventional power supply device shown in FIG. 4 and has a three-phase commercial power supply voltage supplied to an input terminal 1. Is rectified by the rectifier circuit 2 and smoothed by the capacitor 3 to generate a DC voltage. IGB connected in series with this DC voltage
The first switching circuit 4 made up of T6 and 7 and the second switching circuit 5 made up of IGBTs 8 and 9 connected in series convert it into a high-frequency AC voltage of 20 kHz to 50 kHz. The output of the inverter is transformed by the transformer 17, after being transformed, it is rectified by the rectifier 18, and the output is output to the output terminal 19. The input AC power supply may be a single-phase commercial AC power supply, and the IGBTs forming the switching circuits 4 and 5 are MO.
You may use SFET and a bipolar transistor. Further, when outputting alternating current, the rectifier 18 on the output side may be omitted.

The drive device 10 includes drive circuits 11 to 14 for outputting drive signals to the IGBTs 6 to 9 and drive circuits 11 respectively.
A control circuit 15 is provided to control ~ 14.

Reference numeral 48 is a temperature detecting element such as a thermistor arranged in the vicinity of the IGBTs 6 to 9. When the temperature exceeds a predetermined temperature, the temperature detecting element 48 operates to give a stop command to the inverter constituted by the IGBTs 6 to 9. Command the temperature control command device 49. A specific circuit of the temperature control command device 49 is shown in FIG. A comparator 55 is provided with a temperature detecting element 48 and a resistor 54 at its input, and an amplifying transistor 57 and a resistor 56 at its output. Then, when the temperature rises, the comparator 55 is output, the transistor 57 is turned on, and the command signal is output from the terminal 58.

Then, the IGBTs 6 to 9 are arranged on a metal substrate having an insulating layer as shown in FIG. That is,
Reference numeral 21 is a metal substrate made of aluminum, copper, iron or the like having an insulating layer, a copper circuit is laminated on one surface of the metal substrate, and an IGBT circuit is formed on the copper circuit.
Power semiconductor chips 22 to 25 are mounted, surface-mounted and fixed. On the other hand, all or some of the control components of the pulse transformers 26 to 29 and the electronic components 30 to 40 such as resistors, capacitors, ICs and diodes that form the drive circuit are mounted on the printed circuit board 46 and fixed to the upper part of the metal substrate. Has been done. Then, the resin case 41 is placed on the periphery of the metal substrate or in the vicinity thereof, and the case is filled with a protective resin and cured by heating to form a protective resin layer.
Note that 42 to 45 are terminals for external connection.

In the present invention, since the switching circuit is arranged on the metal substrate and the driving circuit is arranged on the metal substrate,
No high frequency noise. Further, since the switching circuit and the driving circuit are mounted on the metal substrate and the printed circuit board in the vicinity thereof at the chip and control component level, the switching circuit is modularized and the driving circuit is smaller than the conventional one in which the driving circuit is arranged on the printed circuit board. Be converted. Further, when used at a high usage rate or when the temperature rises due to fan stop or the like, the temperature control command device 49 stops the inverter via the drive circuit to prevent damage to the arc welding power supply device.

In the above embodiment, the inverter circuit is applied to the full bridge type inverter, but it goes without saying that it can also be applied to the half bridge type inverter and the push pull type inverter.

Further, the power semiconductor chip and the control component are directly surface-mounted on the same metal substrate, the resin case 41 is placed on the periphery of the metal substrate or in the vicinity thereof, and the protective resin is placed inside the case on the printed circuit board. Alternatively, the protective resin layer may be formed by filling up to and curing by heating. Further, although the control components of the driving device are mounted on the printed circuit board, control components required for control such as constant voltage control, constant current control, overcurrent protection, and the like can also be mounted on the printed circuit board. Further, in the above embodiment, the power semiconductor chip of the inverter is directly surface-mounted on the metal substrate, but the power semiconductor chip forming the input rectifier circuit may also be mounted on the metal substrate.

[0018]

As described above, according to the present invention,
Since the power semiconductor chips that make up the switching circuit and the control components of the drive circuit are mounted on the same metal substrate, there is no high-frequency noise and the switching circuit does not malfunction and the coaxial line and There is no need to use special electric wires such as twisted wires. Further, the size of the power source device for arc welding can be reduced as compared with the conventional configuration in which the switching circuits are individually modularized and the drive circuits are arranged on the printed circuit board. Furthermore, when mounting control components on the printed circuit board, mounting and fixing the power semiconductor chip on the copper circuit and fixing the control components to the printed circuit board can be performed separately, and the temperature during soldering of the control components can be controlled. Can be lowered, and damage to control parts can be prevented. Also,
It is possible to protect the power supply device by stopping the inverter even when the temperature of the power semiconductor chip is high due to a high usage rate in the field or the temperature is abnormally increased due to fan stop.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a main part of an embodiment of a power supply device for arc welding of the present invention.

FIG. 2 is a schematic layout view of a module used in the arc welding power supply device of the present invention.

FIG. 3 is a circuit diagram of a temperature control command device of the present invention.

FIG. 4 is a schematic circuit diagram of main parts showing an embodiment of a conventional arc welding power supply device.

[Explanation of symbols]

 2 Rectifier circuit 4,5 Switching circuit 6-9 IGBT 10 Driving device 11-14 Driving circuit 15 Control circuit 21 Metal substrate 22-25 Power semiconductor chip 26-29 Pulse transformer 30-40 Electronic component 41 Resin case 46 Printed circuit board 48 Temperature detection element 49 Temperature control command device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toyoji Yasuda 2-14-3 Awaji, Higashiyodogawa-ku, Osaka-shi, Osaka Makoto Yagi, Inspector, Sansha Electric Manufacturing Co., Ltd. (56) Reference JP-A-5-291783 (JP, A) JP-A-7-9139 (JP, A) Actually developed 55-154688 (JP, U)

Claims (1)

(57) [Claims] 1. A rectifier circuit and a smoothing capacitor for rectifying and smoothing a commercial power supply voltage to generate a DC voltage, and an inverter for converting this DC voltage into an AC voltage having a frequency higher than the commercial power supply frequency. A power semiconductor chip composed of a drive circuit for driving the inverter is mounted and fixed on a copper circuit laminated on one side of the upper surface of a metal substrate having an insulating layer, and the control parts constituting the drive circuit are fixed to a printed circuit board. Or fixedly arranged on the copper circuit, a temperature detection element for instructing the drive circuit to stop the inverter when the temperature is equal to or higher than a predetermined temperature in the vicinity of the power semiconductor chip is mounted on the copper circuit, and further the semiconductor chip and A power supply device for arc welding, wherein the control part is covered with a resin case and the inside of the case is sealed with resin.