JPH067938A - Arc power unit - Google Patents

Abstract

PURPOSE:To miniaturize an arc power unit by forming the power source of a controller for a main inverter and the power source of a fan for cooling a device without using a transformer. CONSTITUTION:This power unit is provided with an input side rectifier 2 which rectifys an alternating current power source, the main inverter 4 which converts the output of this rectifier 2 to the high frequency alternating current, an output transformer 6 which converts the high frequency alternating current, a DC-DC converter 13 which converts the output of rectifier 2 to a control power source of the prescribed voltage, and an inverter controller 15 which is operated with the control power source and drives the main inverter 4. Also an inverter 14 for cooling which converts the output of the rectifier 2 to the alternating current power source, and a fan 12 for cooling the device which is operated with the output of this inverter 14 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc power supply device having an inverter structure.

[0002]

2. Description of the Related Art Conventionally, arc power supply equipment for arc equipment such as arc welders and fusing machines has been miniaturized year by year with the use of inverters as semiconductors have been modularized, inverter technology has been developed, and control systems have been optimally designed. Has been done. And
An example of a conventional arc power supply device having an inverter configuration is configured as shown in FIG.

FIG. 1 shows a configuration in which a three-phase AC power supply is used as an input power supply. The three-phase AC power supply of the system is power supply terminals 1a-1.
Power is supplied to the input side rectifier 2 having a diode bridge configuration via c, and the full-wave rectified output of the rectifier 2 is smoothed by the smoothing capacitor 3 and supplied to the main inverter 4. The main inverter 4 comprises a bridge circuit of semiconductor switches such as transistors and IGBTs, and an inverter controller 5
Based on the PWM drive control, the semiconductor switches are turned on and off to convert the input DC power supply into high frequency AC.

The high frequency AC of the main inverter 4 is transformed by a small output transformer 6 having a high frequency transformer, and then supplied to, for example, an output side rectifier 7 having a diode bridge configuration to be rectified and converted into a DC output terminal. It is output from 8a and 8b. The direct currents of the output terminals 8a and 8b are directly supplied to the load in the case of direct current arc welding, fusing, etc., and are converted to alternating current by an inverter or the like in the case of alternating current arc welding, fusing and the like and supplied to the load.

Further, the three-phase AC power supply of the power supply terminals 1a to 1c is the transformer 9 for the control power supply and the transformer 10 for the cooling power supply.
Is also powered. Then, the secondary side output of the transformer 9 is converted into a DC control power supply of a predetermined voltage by the rectifier 11 having a diode bridge structure and supplied to the controller 5, and the controller 5 operates by DC power supply by this supply.

Further, the secondary side output of the transformer 10 is supplied to a fan 12 having an induction motor structure for cooling the device, and the fan 12 operates from this supply, and the rectifiers 2 and 11 in the device and semiconductor switches of the inverter 4 are operated. , Transformer 9,
Various heating elements such as 10 are cooled. By the way, when the three-phase AC power source of the power supply terminals 1a to 1c becomes either one of two types of power source of 200V system and 400V system, for example, depending on the region of use, etc., the controller 5 is operated according to the voltage of the three-phase AC power source. The control pulse width and so on are switched so that the same voltage DC is generated between the output terminals 8a and 8b regardless of whether it is a 200V system or a 400V system, and it is set to automatically adapt to the two types of power sources. To be done.

In the case of the apparatus shown in FIG. 3, the power frequency of the fan 12 is 60 Hz or 50 Hz depending on the area. Therefore, the capacity of the fan 12 must be set so as to exhibit sufficient cooling capacity even in the area of 50 Hz. , Fan 12
However, there is an inconvenience that it cannot be downsized. Further, in the apparatus of FIG. 3, when the transformer 10 is omitted and the three-phase AC power source (input power source) of the power source terminals 1a to 1c is directly fed to the fan 12,
In particular, when trying to adapt to two types of input power supplies, for example, 200 V power supply and 400 V power supply, the following inconvenience occurs.

That is, when adapting to an input power source of 200V system or 400V system, the power source voltage of the inverter controller 5 and the fan 12 changes according to the input power source. Especially, if the transformer 10 is not provided, the fan 12 is a 400V system. Requires a fan of. As a 400V fan, only a large-capacity large-capacity fan is commercially available. If this commercially-available fan is used, the fan 12 becomes unnecessarily large-capacity large-capacity, and the transformer 12 can be omitted. This causes a problem that the device becomes large.

[0009]

In the case of the conventional device shown in FIG. 3, the main inverter 4 is used for downsizing, but
Large and heavy transformers 9 and 1 having a power source frequency for forming power sources for the inverter controller 5 and the fan 12, respectively.
There is a problem that it requires 0 and cannot be sufficiently miniaturized. In the case of an apparatus using a single-phase AC power source as an input, there are the same problems as described above.

It is an object of the present invention to form a power supply for a controller of a main inverter without using a transformer and to downsize the device. It is also an object to further reduce the size of the device by forming a power source of a fan for cooling the device without using a transformer.

[0011]

In order to achieve the above object, in an arc power supply device of the present invention, an input side rectifier for rectifying an AC power supply, and a main inverter for converting the output of this rectifier into high frequency AC. An output transformer that transforms the high-frequency AC, a DC-DC converter that converts the output of the input side rectifier into a control power supply of a predetermined voltage, and an inverter controller that operates by the control power supply and drives a main inverter.

Further, it is provided with a cooling inverter for converting the output of the rectifier on the input side into an AC power supply, and a fan for cooling the device which operates by the output of this inverter.

[0013]

In the case of the arc power supply device of the present invention configured as described above, since the DC output of the input side rectifier is supplied to the inverter controller as the control power supply for driving via the DC-DC converter, the inverter control is performed. The power supply of the device is formed without using a transformer, and the device is miniaturized.

When the DC output of the rectifier on the input side is converted into AC by the cooling inverter and supplied to the fan for cooling the device, the power source of this fan is also formed without using a transformer, and the device is further miniaturized. To do.

[0015]

EXAMPLE One example will be described with reference to FIGS. In FIG. 1, the same reference numerals as those in FIG. 3 indicate the same elements, and the points different from the conventional apparatus are the following points (1) to (3). (1) The transformer 9 and the rectifier 11 in FIG. 3 are omitted, and DC-DC
The point where the converter 13 is provided. (2) The transformer 10 of FIG. 3 is omitted, and the cooling inverter 14 is used.
Point. (3) An inverter controller 15 for driving and controlling the semiconductor switches of the inverters 4 and 14 is provided instead of the inverter controller 5 of FIG. As shown in FIG. 2, the DC-DC converter 13 includes resistors 13a and 13b for voltage division, an astable multivibrator 13c, a transistor 13d as a high frequency switching element, a high frequency transformer 13e, a diode 13f for reverse voltage absorption, And a full-wave rectifier 13g having a diode bridge configuration. Further, the cooling inverter 14 has a transistor 14 for high frequency switching on each side.
It is formed by a full bridge circuit in which a to 14d are arranged.

Further, the inverter controller 15 is shown in FIG.
The cooling inverter 14 is connected to the controller 5 of 60 Hz described later.
It is formed by adding the function of controlling the drive of the table at a constant frequency. The output of the input side rectifier 2 is the capacitor 3
And is supplied to the main inverter 4 as well as to the DC-DC converter 13 and the cooling inverter 14.

Based on this supply, the DC-DC converter 13 divides the input DC power by the resistors 13a and 13b and supplies it to the astable multivibrator 13c, which triggers the multivibrator 13c to cause the transistor 13 to operate.
High frequency switching of d. Further, this high-frequency switching generates a high-frequency output transformed to the secondary side of the transformer 13e, and this output is full-wave rectified by the rectifier 13g to form a direct current having a rated voltage for feeding to the inverter controller 15. It is supplied to the inverter controller 15 and this controller 15 operates.

The inverter controller 15 is the fan 1
Since the main inverter 4 is driven after 2 is driven, the transistors 14a to 14d of the cooling inverter 14 are first driven by PWM control when the three-phase power supply of the power supply terminals 1a to 1c is turned on. At this time, 60H even in the 50Hz region of Japan
In order to secure sufficient cooling capacity similar to that in the z area, the transistors 14a to 14d are driven at a constant frequency within the range of 60 Hz to 66 Hz.

Further, regardless of whether the three-phase AC power supply (input power supply) of the power supply terminals 1a to 1c is 200V system or 400V system, 200V system low-voltage AC power is supplied to the fan 12, so that the inverter controller 15 is Input power supply 200V system, 4
The control pulse width of the PWM control is changed according to the 00V system. Then, when the fan 12 starts to rotate by the AC power supply of about 200 V of about 60 to 66 Hz of the cooling inverter 14, based on the timer operation or the like, the inverter controller 15
Each semiconductor switch of the main inverter 4 is also driven by PWM control.

By this driving, the main inverter 4 operates in the same manner as the conventional device, the high frequency AC of the main inverter 4 is transformed by the output converter 6, and DC is generated at the output terminals 8a and 8b. The inverter controller 15 changes the control pulse width of the main inverter 4 according to the 200V system and 400V system of the input power source, and holds the DC voltage at the output terminals 8a and 8b constant.

Therefore, in the case of FIG. 1, the large transformers 9 and 10 of the conventional device are omitted, and instead, a small DC-DC converter 13 and a cooling inverter 14 having a semiconductor switch configuration are provided, and the output of the input side rectifier 2 is provided. Is used to form the power supply for the inverter controller 15 and the fan 12, and the device is sufficiently miniaturized. Since the inverter controller 15 and the fan 12 require relatively small electric power, the DC-DC converter 13 and the cooling inverter 14 are formed in a small size by using a semiconductor switch or the like having a small capacity and a small capacity. .

Further, from the cooling inverter 14 to the fan 1
The frequency of the AC power supply supplied to 2 is 60 Hz of the input power supply,
Since it is maintained at a constant frequency of about 60 to 66 Hz regardless of 50 Hz, it is not necessary to upsize the fan 12 to secure sufficient cooling capacity in an area of 50 Hz as in the past, and the fan 12 is upsized. There is nothing to do.

Further, whether the input power of the power supply terminals 1a to 1c is 200V system or 400V system, the voltage of the AC power supply supplied to the fan 12 is a low voltage of 200V system by the PWM control of the inverter controller 15. The fan 12 is a small 200V type, so
A device that automatically adapts to both 0V system and 400V system is formed.

In the above embodiment, the DC-DC converter 13 and the cooling inverter 14 are provided.
Only the DC converter 13 may be provided. Further, it is needless to say that it can be applied when the input power source is a single-phase AC power source. The configuration of each unit in the device is not limited to the embodiment.

[0025]

Since the present invention is configured as described above, it has the following effects. The output of the input side rectifier 2 is supplied to the main inverter 4 and DC-
Since the power is supplied to the DC converter 13 and the output of the converter 13 is used as the power source of the inverter controller 15, it is necessary to transform the AC power source with a large transformer for low frequency to form the power source of the inverter controller as in the conventional case. Therefore, the device is downsized.

When the output of the input side rectifier 2 is also supplied to the cooling inverter 14 and the output of the inverter 14 is used as the power source of the fan 12 for cooling the device, the fan 12 is cooled.
Can be formed without using a conventional large transformer for low frequency, and the device can be further miniaturized.

[Brief description of drawings]

FIG. 1 is a block connection diagram of an embodiment of an arc power supply device of the present invention.

FIG. 2 is a detailed connection diagram of a part of FIG.

FIG. 3 is a block connection diagram of a conventional device.

[Explanation of symbols]

 2 Input side rectifier 4 Main inverter 6 Output transformer 12 Device cooling fan 13 DC-DC converter 14 Cooling inverter 15 Inverter controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Kano 2-14-3 Awaji, Higashiyodogawa-ku, Osaka City Sansha Electric Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. An input-side rectifier that rectifies an AC power supply, a main inverter that converts the output of the input-side rectifier into high-frequency AC, an output transformer that transforms the high-frequency AC, and a predetermined output of the input-side rectifier. An arc power supply device comprising: a DC-DC converter that converts the voltage into a control power supply; and an inverter controller that operates by the control power supply and drives the main inverter. 2. The arc according to claim 1, further comprising: a cooling inverter that converts an output of the input side rectifier into an AC power supply; and a device cooling fan that operates by the output of the cooling inverter. Power supply.