Method and Apparatus For Welding With High Frequency Protection

Abstract

A method and apparatus for providing welding-type power is disclosed. The power supply has two output lines, and two inductances that are magnetically coupled, or a common mode inductance, in the output lines. The inductances may be installed when the power supply is built, or added afterwards. The inductance may protect the welding-type power supply from high frequency noise on a workpiece.

1 . A welding-type power supply having an output across first and second output lines, wherein the first output line includes a first inductance and the second output line includes a second inductance, and further wherein the first inductance and the second inductance are magnetically coupled.  
   
   
       2 . The welding-type power supply of  claim 1 , wherein the first inductance has a differential mode magnitude and the second inductance has the differential mode magnitude.  
   
   
       3 . The welding-type power supply of  claim 2 , wherein the first inductance and the second inductance protect the welding-type power supply from high frequency noise on a workpiece.  
   
   
       4 . The welding-type power supply of  claim 2 , wherein the differential mode magnitude is at most 1 microhenry and the first and second inductances have a common mode inductance of at least 30 microhenrys.  
   
   
       5 . The welding-type power supply of  claim 2 , further comprising at least first and second input power lines, wherein the first input line includes a third inductance and the second input line includes a fourth inductance, and further wherein the third inductance and the fourth inductance are magnetically coupled.  
   
   
       6 . The welding-type power supply of  claim 3 , wherein the third inductance has a second magnitude and the fourth inductance has the second magnitude.  
   
   
       7 . The welding-type power supply of  claim 6 , further comprising capacitances connecting the first and second output lines to ground, wherein the first and second inductances and the capacitances protect the welding-type power supply from high frequency noise on a workpiece.  
   
   
       8 . The welding-type power supply of  claim 6 , wherein the first and second inductances have a common mode inductance of at least 30 times the differential mode magnitude.  
   
   
       9 . The welding-type power supply of  claim 1 , further comprising at least first and second input power lines, wherein the first input line includes a third inductance and the second input line includes a fourth inductance, and further wherein the third inductance and the fourth inductance are magnetically coupled.  
   
   
       10 . The welding-type power supply of  claim 9 , wherein the third inductance and the fourth inductance protect the welding-type power supply from high frequency noise on an input.  
   
   
       11 . The welding-type power supply of  claim 1 , further comprising capacitances connecting the first and second output lines to ground, wherein the first and second inductances and the capacitances protect the welding-type power supply from high frequency noise on a workpiece.  
   
   
       12 . The welding-type power supply of  claim 1 , wherein the first inductance and the second inductance protect the welding-type power supply from high frequency noise on a workpiece.  
   
   
       13 . The welding-type power supply of  claim 1 , wherein the first inductance and the second inductance are wound about a common core.  
   
   
       14 . A welding-type power supply having an output across first and second output lines, wherein the first and second output lines include a common mode inductance.  
   
   
       15 . The welding-type power supply of  claim 14 , wherein the common mode inductance protects the welding-type power supply from high frequency noise on a workpiece.  
   
   
       16 . The welding-type power supply of  claim 15 , wherein the first and second inductances have a common mode inductance of at least 60 times a differential mode magnitude.  
   
   
       17 . The welding-type power supply of  claim 15 , further comprising at least first and second input power lines, wherein the first and second input lines includes a second common mode inductance.  
   
   
       18 . The welding-type power supply of  claim 17 , further comprising capacitances connecting the first and second output lines to ground, wherein the common mode inductance and the capacitances protect the welding-type power supply from high frequency noise on a workpiece.  
   
   
       19 . The welding-type power supply of  claim 14 , further comprising at least first and second input power lines, wherein the first and second input lines includes a second common mode inductance.  
   
   
       20 . A welding-type power supply having an output with an inductance that protects the welding-type power supply from high frequency noise on a workpiece.  
   
   
       21 - 52 . (canceled)