Drive device for roll stands

• US 6,189,352 B1
• Filed: 02/04/1999
• Issued: 02/20/2001
• Est. Priority Date: 05/21/1996
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Wokusch, Johann, Salzmann, Theodor, Klug, Rolf-Dieter
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US09/194,215
• Time in Patent Office: 747 Days
• Field of Search: 72/131, 72/132, 72/143, 72/291, 72/292, 722/49
• US Class Current: 72/14.3
• CPC Class Codes: B21B 37/46 Roll speed or drive motor control B21B37/52, B21B37/60 take precedence
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H05K 7/1432 specially adapted for power drive units or power converters
• CPC Class Codes: H05K 7/14325 for cabinets or racks

Abstract

A driving arrangement for rolling stands of a rolling mill, is described. The driving arrangement includes a control system which prescribes desired values for the rolling stands via control units, the rolling stands having at least one electric motor which is supplied with electric energy by a power supply system via at least one converter having turn-off power semiconductors. The converter has an air-cooled design. The cooling power is dimensioned such that the temperature of the turn-off power semiconductors does not exceed a critical temperature limit for continuous operation. The converter includes heat sinks which have an optimum design. At least some of the heat sinks are connected thermally in parallel.

Claims

1. A driving arrangement for rolling stands of a rolling mill, comprising:

a control system which prescribes predetermined values for the rolling stands via control units; and

at least one air-cooled power converter supplying electric energy from a power supply system to at least one three-phase AC motor of the rolling stands, the at least one air-cooled power converter including turn-off power semiconductors and heat sinks, at least some of the heat sinks being thermally connected in parallel;

wherein a cooling power of the at least one air-cooled power converter is dimensioned such that a temperature of the turn-off power semiconductors does not exceed a critical temperature limit for continuous operation,

wherein the at least one air-cooled power converter includes a DC link, and

wherein the at least one air-cooled power converter is included in a three-point circuit, the three-point circuit having a mean operating frequency less than 250 Hz.

2. The driving arrangement according to claim 1, wherein the heat sinks electrically connect individual ones of the turn-off power semiconductors.

3. The driving arrangement according to claim 1, wherein the at least one air-cooled power converter reacts thermally with a time delay as a function of peak loads due to a thermal capacity of the heat sinks.

4. The driving arrangement according to claim 1, further comprising:

a blower cooling the turn-off power semiconductors, the blower one of i) feeding one of ambient air and pre-cooled air to the heat sinks, and ii) sucks ambient air through the heat sinks.

5. The driving arrangement according to claim 1, wherein the at least one air-cooled power converter is a direct converter.

6. The driving arrangement according to claim 1, wherein the turn-off power semiconductors include gate turn-off thyristors.

7. The driving arrangement according to claim 1, wherein the turn-off power semiconductors include MOS controlled thyristors.

8. The driving arrangement according to claim 1, wherein the turn-off power semiconductors include insulated gate bipolar transistors.

9. The driving arrangement according to claim 1, wherein the turn-off power semiconductors are reverse conducting.

10. The driving arrangement according to claim 1, wherein the at least one air-cooled power converter operates in a power range of 1 to 20 megawatts with reference to a continuous load.

11. The driving arrangement according to claim 10, wherein the power range is 2 to 10 megawatts.

12. The driving arrangement according to claim 1, wherein the at least one air-cooled power converter operates in a power range of 2 to 30 megawatts with reference to an impulse load.

13. The driving arrangement according to claim 12, wherein the power range is 4 to 20 megawatts.

14. A driving arrangement for rolling stands of a rolling mill, comprising:

a control system which prescribes predetermined values for the rolling stands via control units; and

at least one air-cooled power converter supplying electric energy from a power supply system to at least one three-phase AC motor of the rolling stands, the at least one air-cooled power converter including turn-off power semiconductors and heat sinks at least some of the heat sinks being thermally connected in parallel;

wherein a cooling power of the at least one air-cooled power converter is dimensioned such that a temperature of the turn-off power semiconductors does not exceed a critical temperature limit for continuous operation, and

wherein the at least one air-cooled power converters includes two air-cooled power converters, and wherein the at least one three-phase AC motor is connected to the two air-cooled power converters in tandem, the at least one three-phase AC motor including open windings, the two air-cooled power converters feeding the windings bilaterally and having a mean operating frequency less than 100 Hz.

15. The driving arrangement according to claim 14, wherein the control system is designed as a function of characteristics of the at least one air-cooled power converter.

16. The driving arrangement according to claim 14, wherein the at least one power converter is an unfused converter.

17. A driving arrangement for rolling stands of a rolling mill, comprising:

a control system which prescribes predetermined values for the rolling stands via control units; and

at least one air-cooled power converter supplying electric energy from a power supply system to at least one three-phase AC motor of the rolling stands, the at least one air-cooled power converter including turn-off power semiconductors and heat sinks, at least some of the heat sinks being thermally connected in parallel;

wherein a cooling power of the at least one air-cooled power converter is dimensioned such that a temperature of the turn-off power semiconductors does not exceed a critical temperature limit for continuous operation,

wherein the at least one air-cooled power converter includes a DC link, and

wherein the at least one air-cooled power converter is included in an n-point circuit, wherein n is one of greater than and equal to 5, the n-point circuit having a mean operating frequency less than 250 Hz.

18. The driving arrangement according to claim 17, wherein the heat sinks electrically connect individual ones of the turn-off power semiconductors.

19. The driving arrangement according to claim 17, wherein the at least one air-cooled power converter reacts thermally with a time delay as a function of peak loads due to a thermal capacity of the heat sinks.

20. The driving arrangement according to claim 17, further comprising:

a blower cooling the turn-off power semiconductors, the blower one of i) feeding one of ambient air and pre-cooled air to the heat sinks, and ii) sucks ambient air through the heat sinks.

21. The driving arrangement according to claim 17, wherein the at least one air-cooled power converter is a direct converter.

22. The driving arrangement according to claim 17, wherein the turn-off power semiconductors include gate turn-off thyristors.

23. The driving arrangement according to claim 17, wherein the turn-off power semiconductors include MOS controlled thyristors.

24. The driving arrangement according to claim 17, wherein the turn-off power semiconductors include insulated gate bipolar transistors.

25. The driving arrangement according to claim 17, wherein the turn-off power semiconductors are reverse conducting.

26. The driving arrangement according to claim 17, wherein the at least one air-cooled power converter operates in a power range of 1 to 20 megawatts with reference to a continuous load.

27. The driving arrangement according to claim 26, wherein the power range is 2 to 10 megawatts.

28. The driving arrangement according to claim 17, wherein the at least one air-cooled power converter operates in a power range of 2 to 30 megawatts with reference to an impulse load.

29. The driving arrangement according to claim 28, wherein the power range is 4 to 20 megawatts.