Method for operating an electrical machine

• US 9,337,765 B2
• Filed: 01/15/2013
• Issued: 05/10/2016
• Est. Priority Date: 03/01/2012
• Status: Active Grant

• Current Assignee: Siemens Energy Global GmbH & Co. KG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Strack, Sebastian
• Primary Examiner(s): DUDA, RINA I
• Application Number:
  US14/379,907
• Publication Number:
  US 20150022132A1
• Time in Patent Office: 1,211 Days
• Field of Search: 318/140, 318/629, 318/632
• US Class Current: 1/1
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33
• CPC Class Codes: H02K 11/21 Devices for sensing speed or position, or actuated thereby specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14
• CPC Class Codes: H02K 3/505 for large machine windings, e.g. bar windings H02K3/51 takes precedence
• CPC Class Codes: H02P 23/0077 Characterised by the use of a particular software algorithm
• CPC Class Codes: H02P 9/006 Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10
• CPC Class Codes: H02P 9/14 by variation of field H02P9/08, H02P9/10 take precedence
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Abstract

A method for operating an electrical machine having a stator 1 with a coil from electrical conductors, which has two coil ends 2 lying opposite each other. The method includes simultaneously recording vibration measurements by means of which the elliptic vibration modes of the two coil ends 2 can be determined as a factor of time; determining the ellipse inclinations and the phase positions of elliptic vibration modes of the two coil ends 2; determining critical operating states of the electrical machine, in which the elliptic inclinations and the phase positions of the elliptic vibration modes of the two coil ends are substantially identical; and operating the electrical machine in such a manner that the critical operating states can be avoided by varying the idle power of the electrical machine.

Claims

1. A method for operating an electrical machine which comprises a stator having a coil of electrical conductors, the coil comprising two coil ends that lie opposite one another on the coil;

the method comprising the steps;

simultaneously determining vibration measurement values with which it is possible to determine elliptic vibration modes of the two coil ends in dependence upon time;

also determining ellipse inclinations and phase positions of the elliptic vibration modes of the two coil ends;

also determining critical operating states of the electrical machine at which the elliptic inclinations and the phase positions of the elliptic vibration modes of the two coil ends are essentially identical; and

then operating the electrical machine in such that the critical operating states are avoided by varying idle power of the electrical machine so that the ellipse inclinations and the phase positions of the elliptic vibration modes of the two coil ends are not essentially identical.

2. The method as claimed in claim 1, further comprising determining the vibration measurement values of the coil ends at at least eight and at a maximum twelve measuring points that are uniformly distributed along the circumference of each of the coil ends and that are all arranged at the same axial position on their respective coil ends.

3. The method as claimed in claim 1, wherein the stator comprises a lamination stack and the method further comprises the following steps:

determining vibration measurement values selected to enable determining the elliptic vibration mode of the lamination stack in dependence upon time, and simultaneously determining the vibration measurement values, selected to enable determining the elliptic vibration modes of the two coil ends;

determining further critical operating states of the electrical machine in which the ellipse inclinations and the phase positions of the elliptic vibration modes of the lamination stack and at least one of the coil ends are essentially identical; and

then operating the electrical machine in such that the further critical operating states are avoided by varying the idle power so that the ellipse inclinations and the phase positions of the elliptic vibration modes of the lamination stack and of the two coil ends are not essentially identical.

4. The method as claimed in claim 3, further comprising:

determining the vibration measurement values of the lamination stack at an axial location in the stator that lies in a center of the coil between the two coil ends.

5. The method as claimed in claim 4, further comprising:

determining the vibration measurement values of the lamination stack at at least eight and at a maximum twelve measuring points that are distributed uniformly along the circumference of the coil ends and that are all arranged at the same axial position on their respective coil ends.

6. The method as claimed in claim 3, further comprising the steps:

determining a pole wheel angle and a phase angle of the electrical machine;

creating a characteristic field in which the critical and the further critical operating states of the electrical machine are plotted in dependence upon the pole wheel angle and the phase angle, and with reference to the characteristic field for avoiding the critical operating states.

7. The method as claimed in claim 1, further comprising determining of the elliptic vibration modes comprises:

transforming the vibration measurement values into a frequency spectrum.

8. The method as claimed in claim 1, wherein the vibration measurement values are displacements, speeds and/or accelerations of the measurement points.

9. The method as claimed in claim 8, further comprising determining the displacements that occur in the radial direction, the speeds that occur in the radial direction and/or the accelerations that occur in the radial direction.

10. The method as claimed in any one of claim 1, further comprising avoiding the critical operating states and/or the further critical operating states by varying the effective power.

11. The method as claimed in claim 3, further comprising determining the vibration measurement values of the lamination stack at at least eight and at a maximum twelve measuring points that are distributed uniformly along the circumference of the coil core and that are all arranged in the same axial position on their respective coil ends.

12. The method as claimed in claim 1, further comprising the determining of the elliptic vibration modes comprises transforming the vibration measurement values into a frequency spectrum.