Method and Apparatus For Providing Welding Type Power With Balanced Bus

• US 20150060426A1
• Filed: 11/07/2014
• Published: 03/05/2015
• Est. Priority Date: 07/23/2012
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Schartner, Quinn W., Vogel, Bernard J., Nelson, Andrew D.
• Granted Patent: US 10,500,669 B2
• Time in Patent Office: Days
• US Class Current: 219/130.21
• CPC Class Codes: B23K 9/1043 characterised by the electric circuit B23K9/1012 takes precedence
• CPC Class Codes: B23K 9/1062 with computing means
• CPC Class Codes: B23K 9/173 and of a consumable electrode
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10

Abstract

A welding-type power supply includes a controller, bus (that can, but need not be preregulated), and an output converter. The controller has a preregulator control output and an output converter control output. The controller may receive bus feedback indicative of a plurality of bus voltages. A bus voltage balancing module in the converter includes a scaled correction module responsive to the bus feedback signal, and the converter control output is responsive to the bus voltage balancing module. The controller may receive load feedback indicative of a load output, have a bus voltage balancing module that includes a load proportional gain module responsive to the load.

Claims

1. A welding-type power supply comprising:

a bus;

an output converter, disposed to receive the bus and to provide a welding type power output, and having a control input, wherein switches in the output converter are controlled by the control input; and

a controller that receives a bus feedback signal indicative of a plurality of bus voltages, and wherein the controller has a converter control output connected to the control input, and wherein the controller has a bus voltage balancing module that includes a scaled correction module responsive to the bus feedback signal, and wherein the converter control output is responsive to the bus voltage balancing module.

2. The welding-type power supply of claim 1, wherein the bus is a preregulated bus and the controller further receives load feedback indicative of a load output, and wherein the bus voltage balancing module further includes a load proportional gain module responsive to the load feedback.

3. The welding-type power supply of claim 1, wherein the controller further receives OCV feedback indicative of an OCV or load condition, and wherein the bus voltage balancing module further includes a duty cycle limiting module responsive to the OCV feedback.

4. The welding-type power supply of claim 2, wherein the converter includes at least one stacked inverter circuit.

5. The welding-type power supply of claim 4, further comprising a preregulator that provides power to the preregulated bus.

6. The welding-type power supply of claim 2, wherein the output converter includes a stacked full bridge inverter.

7. The welding-type power supply of claim 1, wherein the bus is a preregulated bus and further is a split bus with a first bus voltage and a second bus voltage and the bus feedback signal is responsive to a difference between the first and second bus voltages exceeding a threshold.

8. A method of providing welding-type power, comprising:

providing a bus;

converting the bus using a switched converter to a welding type power output; and

controlling the converting in response to bus feedback indicative of a plurality of bus voltages by adjusting pulse widths of switches in the converter in proportion, over a range, to a difference between the plurality of bus voltages to balance the bus.

9. The method of claim 8, wherein providing a bus includes providing a preregulated bus and wherein the switched converter is a stacked inverter having at least two inverters and the preregulated bus is a split bus having two bus voltages, each feeding an inverter and the plurality of bus voltages are the two bus voltages, and adjusting includes providing a greater pulse width a first one of the two inverters, wherein the first one of the two inverters receives a bus voltage that is greater than a second bus voltage received by a second inverter, wherein the pulse width is greater in proportion, over a range, to a difference between the plurality of bus voltages, thereby balancing the preregulated bus.

10. The method of claim 9, further comprising receiving load feedback indicative of a load output, and adjusting pulse widths of switches in the converter in inverse proportion, over a range, to the load feedback.

11. The method of claim 8, further comprising receiving OCV feedback indicative of an OCV or load condition, and limiting the duty cycle of the switched converter in response to the OCV feedback.

12. A welding-type power supply comprising:

a preregulator bus;

an output converter, disposed to receive the preregulator bus and to provide a welding type power output, and having a control input, wherein switches in the output converter are controlled by the control input; and

a controller that receives load feedback indicative of a load output, and wherein the controller has a converter control output connected to the control input, and wherein the controller has a bus voltage balancing module that includes a load proportional gain module responsive to the load feedback.

13. The welding-type power supply of claim 12, wherein the controller further receives a bus feedback signal indicative of a plurality of bus voltages, and wherein the bus voltage balancing module further includes a scaled correction module responsive to the bus feedback signal, and wherein the converter control output is responsive to the bus voltage balancing module.

14. The welding-type power supply of claim 12, wherein the controller further receives OCV feedback indicative of an OCV or load condition, and wherein the bus voltage balancing module further includes a duty cycle limiting module responsive to the OCV feedback.

15. The welding-type power supply of claim 12, wherein the converter includes at least one stacked inverter circuit.

16. The welding-type power supply of claim 15, further comprising a preregulator that provides power to the preregulator bus.

17. The welding-type power supply of claim 16, wherein the output converter includes a stacked full bridge inverter.

18. A method of providing welding-type power, comprising:

providing a split preregulated bus having a first and second bus voltage;

converting the preregulated bus to a welding type power output, using a stacked inverter, wherein a first inverter receives the first bus voltage and a second inverter receives the second bus voltage; and

controlling the converting in response to bus feedback indicative of a plurality of bus voltages by adjusting pulse widths of switches in the converter in proportion, over a range, to a difference between the first and second bus voltages to balance the preregulated bus and further receiving load feedback indicative of a load output, and adjusting pulse widths of switches in the inverters in inverse proportion, over a range, to the load feedback.

19. The method of claim 18, further comprising receiving load feedback indicative of a load output, and adjusting pulse widths of switches in the inverters in inverse proportion, over a range, to the load feedback.

20. The method of claim 19, further comprising receiving load feedback indicative of an OCV or load condition, and limiting the duty cycle of the switched converter in response to the load feedback.