Output control method for consumable electrode arc welding power source

Patent metadata

Field	Value
Publication number	US-9278402-B2
Application number	US-58939806-A
Country	US
Kind code	B2
Filing date	Oct 30, 2006
Priority date	Nov 7, 2005
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

In the output control method for a consumable electrode arc welding power source, entire application range of an welding current is segmentalized into a plurality of current zones, a norm welding voltage value is set for each of the current zones, a welding current and a welding voltage are detected at each of minute cycles, the current zone which corresponds to a detected value of the welding current is selected, a fluctuation range is calculated with the norm welding voltage value of the selected current zone as a center value, a welding voltage limit value is calculated while the welding voltage detected value is limited to within the fluctuation range, and the output of the welding power source is controlled based on this welding voltage limit value.

First claim

The invention claimed is:

1. An output control method for a consumable electrode arc welding power source in which an output of the welding power source is controlled based on an amplified error value between a predetermined voltage setting value and a welding voltage, the method comprising:
segmentalizing a continuously changing portion, in an arc period, of a welding current into a plurality of current zones of equal current width including a first current zone and a second current zone, and the welding current changes continuously over the entire arc period,
setting a norm welding voltage value for each of the current zones,
detecting a welding current and a welding voltage at each of minute cycles,
selecting one of the current zones which corresponds to a value of the detected welding current,
calculating a fluctuation range with the norm welding voltage value of the selected current zone as a center value,
calculating a welding voltage limit value while the detected value of the welding voltage is limited to within the fluctuation range,
calculating the amplified error value using the voltage setting value and the welding voltage limit value and generating an error amplification signal, and
directing the error amplification signal to the welding power source to control the output,
wherein the fluctuation range within each of the first current zone and the second current zone is constant, and the fluctuation range in the first current zone differs from the fluctuation range in the second current zone.

2. The method according to claim 1 , wherein a moving average of the welding voltage limit values is obtained for each of the current zones for the calculation of the norm welding voltage value for each of the current zones.

3. The method according to claim 1 , wherein an output voltage which is a voltage at a point on a output path in the welding power source before the reactor mounted on the output path is detected, a deviation between the detected value of the welding voltage and the welding voltage limit value is calculated, a voltage control setting value is calculated by adding the deviation to the voltage setting value, and the amplified error value is calculated using the voltage control setting value and the detected value of the output voltage.

4. The method according to claim 1 , wherein each of the norm welding voltage values in all of the current zones is modified based on a change amount of the voltage setting value in the case that the voltage setting value changes.

5. An output control method for a consumable electrode arc welding power source in which an output of a welding power source is controlled based on an amplified error value between a predetermined voltage setting value and a welding voltage, the method comprising:
forming a norm operational point trajectory which indicates a relation between a welding current and welding voltage during an arc period while no abnormal voltage is superimposed on the welding voltage,
detecting a welding current and a welding voltage at each of minute cycles,
calculating a norm welding voltage value which corresponds to a detected value of the welding current based on the norm operational point trajectory,
calculating a fluctuation range with the norm welding voltage value as a center value,
calculating a welding voltage limit value while the detected value of the welding voltage is limited to within the fluctuation range,
calculating the amplified error value using the voltage setting value and the welding voltage limit value and generating an error amplification signal,
directing the error amplification signal to the welding power source to control the output,
wherein the norm operational point trajectory is calculated as a continuously changing linear line represented as Vc=a×i+b, where Vc is welding voltage; i is welding current; and a & b are constants, for each of predetermined calculation cycles while welding is performed using operational points data constituted from the detected value of the welding current and the corresponding welding voltage value in each of the minute cycles while no abnormal voltage is superimposed on the welding voltage.

6. The method according to claim 5 , wherein the norm operational point trajectory is modified toward a direction of a welding voltage axis based on a change amount of the voltage setting value in the case that the voltage setting value changes.

7. The method according to claim 5 , wherein the norm operational point trajectory is set differently for a plurality of portions to be welded.

Assignees

• Uezono Toshiro
• Era Tetsuo
• Daihen Corp

Inventors

• Uezono Toshiro
• Era Tetsuo

Classifications

• B23K9/0731 Primary

  Stabilising of the arc tension · CPC title