Power source including parallel switching circuits and related methods for a welding or cutting system

Claim 2

A power source for a welding or cutting system, the power source comprising: a plurality of electrical power generating means for generating respective electrical output power signals; blocking means operably connected to said electrical power generating means for isolating each of said electrical power generating means from the remaining plurality of electrical power generating means; combining means for combining said plurality of electrical output power signals into a combined electrical output power signal; and control means coupled to said plurality of electrical power generating means for controlling said plurality of electrical power generating means in response to a desired output for the power source so that a ripple portion of said combined power output signal has an RMS ripple component less than 5 percent of an average of said combined output power signal.

Claim 3

A power source as defined in claim 1 wherein said combining means comprises means for combining said plurality of electrical output power signals in parallel.

Claim 4

A power source as defined in claim 1, wherein each of said electrical power generating means comprises a respective switch for switching electrical power to generate said respective electrical output power signal; and wherein said control means includes a synchronizer positioned in electrical communication with said switches for synchronizing opening and closing of said switches so that said switches switch electrical power at a common duty cycle.

Claim 5

A power source as defined in claim 3 wherein said synchronizer maintains a 360/N degree phase relationship between switching of said switches, wherein N is the number of electrical power generating means.

Claim 6

A power source as defined in claim 3 wherein each of said plurality of switches comprises at least one insulated gate bipolar transistor.

Claim 7

A power source for a welding or cutting system, the power source comprising: a plurality of electrical power generating means, wherein each electrical power generating means includes a switch for switching electrical power to generate a respective electrical output power signal; combining means for combining the plurality of electrical output power signals into a combined electrical output power signal; control means coupled to said plurality of electrical power generating means for controlling said electrical power generating means, wherein said control means includes a synchronizer positioned in electrical communication with said plurality of switches for synchronizing opening and closing of said switches, and wherein said synchronizer comprises: a timing signal generator for generating a timing signal having a predetermined frequency; a ramp input generator for generating a plurality of ramp input signals responsive to the timing signal of said timing signal generator, the plurality of ramp input signals being 360/N degrees out of phase with respect to each other wherein N is the number of electrical power generating means and the plurality of ramp input signals having a frequency equal to 1/N of the predetermined frequency; a plurality of modulation ramp generators for generating a plurality of modulation ramp signals in response to the plurality of ramp input signals, wherein the modulation ramp signals are 360/N degrees out of phase with respect to each other and wherein each of the modulation ramp signals has a frequency equal to 1/N of the predetermined frequency; and a plurality of ramp comparators for comparing the modulation ramp signals with the respective input signals for said plurality of respective switches, and for generating a plurality of respective switch drive signals in response thereto, so that said synchronizer maintains a 360/N degree phase relationship between switching of said plurality of switches such that said switches switch electrical power at a common duty cycle and a ripple portion of said combined power output signal has an RMS ripple component less than 5 percent of an average of said combined output power signal at a different phase.

Claim 8

A power source for a welding or cutting system, the power source comprising: a plurality of electrical power generating means, wherein each electrical power generating means includes a switch for switching electrical power to generate a respective electrical output power signal; combining means for combining the plurality of electrical output power signals into a combined electrical output power signal; control means coupled to said plurality of electrical power generating means for controlling said electrical power generating means, wherein said control means includes a synchronizer positioned in electrical communication with said plurality of switches for synchronizing opening and closing of said switches, and wherein said synchronizer comprises: a timing signal generator for generating a timing signal having a predetermined frequency; a ramp input generator for generating a plurality of ramp input signals responsive to the timing signal of said timing signal generator, the plurality of ramp input signals being 360/N degrees out of phase with respect to each other wherein N is the number of electrical power generating means and the plurality of ramp input signals having a frequency equal to 1/N of the predetermined frequency; a plurality of modulation ramp generators for generating a plurality of modulation ramp signals in response to the plurality of ramp input signals, wherein the modulation ramp signals are 360/N degrees out of phase with respect to each other and wherein each of the modulation ramp signals has a frequency equal to 1/N of the predetermined frequency; and a plurality of ramp comparators for comparing the modulation ramp signals with the respective input signals for said plurality of respective switches, and for generating a plurality of respective switch drive signals in response thereto, so that said synchronizer maintains a 360/N degree phase relationship between switching of said plurality of switches such that said switches switch electrical power at a common duty cycle and a ripple portion of said combined power output signal has an RMS ripple component less than 5 percent of an average of said combined output power signal at a different phase.

Claim 9

A power source as defined in claim 6 wherein said control means further includes a plurality of respective feedback sensors respectively positioned in electrical communication with said switches for sensing respective outputs from each of said respective switches and for providing a plurality of respective feedback signals in response thereto, and a feedback correction circuit comprising: a desired signal generator for generating a desired power output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of switches and for generating an actual output signal in response thereto; an error comparator for comparing the desired output signal and the actual output signal and generating an error signal in response thereto; a plurality of summing circuits for summing the error signal with each of said plurality of feedback signals, and for generating respective input signals in response thereto.

Claim 10

A power source for a welding or cutting system, the power source comprising: a plurality of power switching circuits connected in parallel, wherein each power switching circuit includes a respective switch for switching electrical power to a respective output; blocking means operably connected to said power switching circuits for isolating each one of said power switching circuits from the remaining power switching circuits; and a controller for controlling said plurality of switches in response to a desired output for said power source, said controller including a synchronizer for synchronizing said plurality of switches so that each of said switches switches electrical power at a common duty cycle.

Claim 11

A power source for a welding or cutting system, the power source comprising: a plurality of power switching circuits connected in parallel, wherein each power switching circuit includes a respective switch for switching electrical power to a respective output; blocking means operably connected to said power switching circuits for isolating each one of said power switching circuits from the remaining power switching circuits; and a controller for controlling said plurality of switches in response to a desired output for said power source, said controller including a synchronizer for synchronizing said plurality of switches so that each of said switches switches electrical power at a common duty cycle.

Claim 12

A power source as defined in claim 8 wherein said synchronizer maintains a 360/N degree phase relationship between switching of said plurality of switches, wherein N is the number of power switching circuits.

Claim 13

A power source as defined in claim 9 wherein said synchronizer comprises: a timing signal generator for generating a timing signal having a predetermined frequency; a ramp input generator for generating a plurality of ramp input signals responsive to the timing signal of said timing signal generator, the plurality of ramp input signals being 360/N degrees out of phase with respect to each other and the plurality of ramp input signals having a frequency equal to 1/N of the predetermined frequency; a plurality of modulation ramp generators for generating a plurality of modulation ramp signals in response to the plurality of ramp input signals, wherein the modulation ramp signals are 360/N degrees out of phase with respect to each other and wherein each of the modulation ramp signals has a frequency equal to 1/N of the predetermined frequency; and a plurality of ramp comparators for comparing the plurality of modulation ramp signals with the respective input power signals for said respective switching circuits, and for generating a plurality of respective switch drive signals in response thereto.

Claim 14

A power source as defined in claim 10 wherein said controller further includes a plurality of respective feedback sensors for sensing respective outputs from each of said plurality of respective power switching circuits and for providing a plurality of respective feedback signals in response thereto, and wherein said controller includes a feedback correction circuit comprising: a signal generator for generating a desired power output signal in response to the desired output; an output sensor for sensing a combined output of said switches and for generating an actual output signal in response thereto; an error comparator for comparing the desired output signal and the actual output signal and generating an error signal in response thereto; a plurality of summing circuits for individually summing the error signal with each respective feedback signal, and for generating respective input signals in response thereto.

Claim 15

A power source as defined in claim 8 wherein said controller includes a feedback control circuit comprising: a signal generator for generating a desired output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of power switching circuits and for generating an actual output signal in response thereto; and an adjusting circuit for adjusting switching of said plurality of switches in response to a comparison of the desired output signal and the actual output signal.

Claim 16

A power source as defined in claim 8 wherein each of said plurality of switches comprises at least one insulated gate bipolar transistor.

Claim 17

A power source for a welding or cutting system, the power source comprising: a plurality of power switching circuits connected in parallel, wherein each power switching circuit includes a respective switch for switching electrical power to a plurality of outputs; a controller including a synchronizer for synchronizing said switches so that each of said switches switch electrical power at a common duty cycle and further including a feed back control circuit comprising: a signal generator for generating a desired output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of power switching circuits and for generating an actual output signal in response thereto; an adjusting circuit for adjusting switching of said switches in response to a comparison of the desired output signal and the actual output signal; and a plurality of respective feedback sensors for sensing respective outputs from each of said respective power switching circuits and for generating a plurality of respective feedback signals, wherein said adjusting circuit generates an error signal in response to the comparison of the desired and actual output signals, and wherein said adjusting circuit sums the error signal with each of said plurality of feedback signals such that said control means controls said switches in response to a desired output for said power source.

Claim 18

A power source for a welding or cutting system, the power source comprising: a plurality of power switching circuits connected in parallel, wherein each power switching circuit includes a respective switch for switching electrical power to a plurality of outputs; a controller including a synchronizer for synchronizing said switches so that each of said switches switch electrical power at a common duty cycle and further including a feed back control circuit comprising: a signal generator for generating a desired output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of power switching circuits and for generating an actual output signal in response thereto; an adjusting circuit for adjusting switching of said switches in response to a comparison of the desired output signal and the actual output signal; and a plurality of respective feedback sensors for sensing respective outputs from each of said respective power switching circuits and for generating a plurality of respective feedback signals, wherein said adjusting circuit generates an error signal in response to the comparison of the desired and actual output signals, and wherein said adjusting circuit sums the error signal with each of said plurality of feedback signals such that said control means controls said switches in response to a desired output for said power source.

Claim 19

A cutting or welding system comprising: a power source for generating electrical power, said power source comprising; connection means for connecting said power source to an external power supply; a plurality of power switching circuits connected in parallel and including a respective switch for switching electrical power from the external power supply to a respective output; blocking means operably connected to said power switching circuits for isolating each power switching circuit from the remaining power switching circuits; and a controller for controlling said switches in response to a desired output for said power source, said controller including a synchronizer for synchronizing said switches so that each of said switches switch electrical power at a common duty cycle; and an electrode for generating an electric arc between said electrode and the workpiece in response to the electrical power generated by said power source.

Claim 20

A cutting or welding system comprising: a power source for generating electrical power, said power source comprising; connection means for connecting said power source to an external power supply; a plurality of power switching circuits connected in parallel and including a respective switch for switching electrical power from the external power supply to a respective output; blocking means operably connected to said power switching circuits for isolating each power switching circuit from the remaining power switching circuits; and a controller for controlling said switches in response to a desired output for said power source, said controller including a synchronizer for synchronizing said switches so that each of said switches switch electrical power at a common duty cycle; and an electrode for generating an electric arc between said electrode and the workpiece in response to the electrical power generated by said power source.

Claim 21

A system as defined in claim 15, wherein said system further comprises: positioning means for positioning said electrode relative to the workpiece.

Claim 22

A system as defined in claim 15 wherein said synchronizer maintains a 360/N degree phase relationship between switching of said switches, wherein N is the number of power switching circuits.

Claim 23

A system as defined in claim 17 wherein said synchronizer comprises: a timing signal generator for generating a timing signal having a predetermined frequency; a ramp input generator for generating a plurality of ramp input signals responsive to the timing signal of said timing signal generator, the ramp input signals being 360/N degrees out of phase with respect to each other and the ramp input signals having a frequency equal to 1/N of the predetermined frequency; a plurality of modulation ramp generators for generating a plurality of modulation ramp signals in response to the plurality of ramp input signals, wherein the modulation ramp signals are 360/N degrees out of phase with respect to each other and wherein each of the modulation ramp signals has a frequency equal to 1/N of the predetermined frequency; and a plurality of ramp comparators for comparing the modulation ramp signals with a plurality of respective input signals for said respective plurality of power switching circuits, and for generating a plurality of respective switch drive signals in response thereto.

Claim 24

A system as defined in claim 18 wherein said controller further includes a plurality of respective feedback sensors for sensing respective outputs from each of said respective power switching circuits and for providing a plurality of respective feedback signals in response thereto, and wherein said controller includes a feedback correction circuit comprising: a desired signal generator for generating a desired output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of power switching circuits and for generating an actual output signal in response thereto; an error comparator for comparing the desired output signal and the actual output signal and generating an error signal in response thereto; a plurality of summing circuits for individually summing the error signal with each respective feedback signal, and for generating respective input signals in response thereto.

Claim 25

A system as defined in claim 15 wherein said controller includes a feedback control circuit comprising: a desired signal generator for generating a desired output signal in response to the desired output; an output sensor for sensing a combined output of said plurality of power switching circuits and for generating an actual output signal in response thereto; and an adjusting circuit for adjusting switching of said switches in response to a comparison of the desired output signal and the actual output signal.

Claim 26

A system as defined in claim 20 wherein said controller further includes a plurality of respective feedback sensors for sensing respective outputs from each of said respective power switching circuits, wherein said adjusting circuit generates an error signal in response to the comparison of the desired and actual output signals, and wherein said adjusting circuit sums the error signal with each of the feedback signals.

Claim 27

A system as defined in claim 15 wherein each of said switches comprises an insulated gate bipolar transistor.

Claim 30

A method as defined in claim 23 further comprising the step of: synchronizing said switching of power so that a 360/N degree phase relationship is maintained between switching of the plurality of power switching circuits, wherein N is the number of power switching circuits.

Claim 31

A method as defined in claim 23 further comprising the steps of: sensing a combined output of said plurality of power switching circuits; comparing the desired output and the combined output; and adjusting switching of said plurality of switching circuits in response to said comparison of the desired output and the combined output.

Claim 34

A method as defined in claim 26 further comprising the steps of: sensing a plurality of respective outputs from said plurality of power switching circuits; sensing a combined output of said plurality of power switching circuits; comparing the desired output and the combined output to determine an error signal; and individually summing the error signal with each of the sensed outputs to determine a respective input signal.

Claim 39

A method as defined in claim 29, wherein the step of synchronizing maintains a 360/N degree phase relationship between the combining of the plurality of electrical output power signals, wherein N is the number of electrical output power signals.

Claim 40

A power source for an electric arc tool, the power source comprising: a plurality of power switching circuits, each of said power switching circuits including a respective switch for switching electrical power to a respective output, the respective outputs of each of said plurality of power switching circuits being connected in parallel; blocking means operably connected to said electrical power generating means for isolating each electrical power generating means from the remaining electrical power generating means; and a controller for controlling said plurality of power switching circuits in response to a desired power output for said power source, said controller including a synchronizer for synchronizing said plurality of switching circuits so that each of said switches switch electrical power at a common duty cycle.

Claim 41

A power source for an electric arc tool, the power source comprising: a plurality of power switching circuits, each of said power switching circuits including a respective switch for switching electrical power to a respective output, the respective outputs of each of said plurality of power switching circuits being connected in parallel; blocking means operably connected to said electrical power generating means for isolating each electrical power generating means from the remaining electrical power generating means; and a controller for controlling said plurality of power switching circuits in response to a desired power output for said power source, said controller including a synchronizer for synchronizing said plurality of switching circuits so that each of said switches switch electrical power at a common duty cycle.

Claim 42

A power source for an electric arc tool as defined in claim 31: wherein said plurality of power switching circuits comprises a predetermined number of power switching circuits including a first and a second power switching circuit; and wherein said synchronizer maintains a phase relationship between switching of said first and second power switching circuits, said phase relationship being equal to about 360 degrees divided by said predetermined number.

Claim 43

A power source for an electric arc tool as defined in claim 32 wherein said synchronizer evenly distributes switching of said power switching circuits across a switching period, so that said phase relationship is maintained between consecutively switched switching circuits.

Claim 44

A power source for an electric arc tool as defined in claim 31 wherein each of said switches comprises at least one insulated gate bipolar transistor.