System having a first electric motor and a second electric motor for driving a string

Patent metadata

Field	Value
Publication number	US-9973117-B2
Application number	US-201514706589-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	Nov 7, 2012
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

An exemplary system includes a first electric motor and a second electric motor, which are coupled mechanically to one another via a common string of the system. The string has a torsional natural oscillation at a natural frequency. A first oscillating torque acts on the string by the first electric motor and a second oscillating torque acts on the string by the second electric motor. The second electric motor is arranged with respect to the first electric motor such that the effect of the second oscillating torque on the string results in damping of the excitation of the natural oscillation owing to the first oscillating torque.

First claim

What is claimed is:

1. A system comprising:
a first electric motor and a second electric motor, which are coupled mechanically to one another via a common string,
wherein the string has a torsional natural oscillation at a natural frequency,
wherein a first oscillating torque acts on the string by the first electric motor and a second oscillating torque acts on the string by the second electric motor, and
wherein the first electric motor and the second electric motor are arranged on respectively opposite end regions of the string, and
wherein the second electric motor is arranged with respect to the first electric motor such that an effect of the second oscillating torque on the string results in damping of an excitation of the natural oscillation by the first oscillating torque.

2. The system as claimed in claim 1 , wherein the first electric motor is driven by a first drive, and the second electric motor is driven by a second drive, wherein the first drive and the second drive are current-source DC-link converters.

3. The system as claimed in claim 1 , wherein one of the two electric motors is a synchronous machine.

4. The system as claimed in claim 1 , wherein the first electric motor and the second electric motor is a synchronous machine.

5. The system as claimed in claim 1 , wherein the first electric motor is driven by a first drive, and the second electric motor is driven by a second drive, wherein the first drive and the second drive are connected to a supply grid via phase conductors, the first drive has a first converter and the second drive has a second converter, wherein the first converter and the second converter are in each case externally commutated power converters on a side of the supply grid and on a side of the first electric motor and the second electric motor, respectively.

6. The system as claimed in claim 5 , wherein the second converter is operated with a phase shift through a phase shift angle Δph N with respect to the first converter.

7. The system as claimed in claim 6 , wherein the second drive has a second transformer, by which the phase shift through the phase shift angle Δph N is realized.

8. The system as claimed in claim 7 , wherein the second electric motor is arranged to be radially rotated through a relative motor angle Δph M with respect to the first motor, wherein the relative motor angle is at least approximately

Δ
⁢

⁢

ph
M

=

Δ
⁢

⁢

ph
N

360
⁢

⁢
deg

⁢

1

f
N

⁢

N
N

1
/

f
M

-

1
/

f
N

⁢

(

360
⁢

°
/

N
M

)

,

where f N is a frequency of the supply grid, f M is a frequency of the load-side power converter, N N is a pulse number of a grid-side power converter, N M is the pulse number of a load-side power converter.

9. The system as claimed in claim 8 , wherein the second stator is arranged to be rotated radially through a stator angle φ St with respect to the first stator, the second rotor is arranged to be rotated radially through a rotor angle φ R with respect to the first rotor, wherein Δph M =−φ St holds true for the relative motor angle.

10. The system as claimed in claim 9 , wherein the phase shift angle Δph N is a grid-side electrical phase shift angle between the first converter and the second converter.

11. The system as claimed in claim 5 , wherein the first converter and the second converter are each twelve-pulse power converters on the side of the supply grid and on the side of the first electric motor or the second electric motor.

12. The system as claimed in claim 11 , wherein in each case one grid-side power converter of the first converter and of the second converter is an externally commutated thyristor power converter with phase gating control.

13. The system as claimed in claim 11 , wherein in each case one load-side power converter of the first converter and of the second converter is in the form of an externally commutated thyristor power converter with phase gating control.

14. The system as claimed in claim 1 , wherein the string has a compressor system as a load.

15. The system as claimed in claim 1 , wherein the first electric motor and the second electric motor together have at least a power of 60 MW.

16. The system as claimed in claim 1 , wherein the first electric motor has a first rotor and a first stator, the second electric motor has a second rotor and a second stator, wherein the second rotor is not radially aligned with the first rotor and/or the second stator is not radially aligned with the first stator.

Assignees

• Abb Technology Ag
• Abb Schweiz Ag

Inventors

• Pieder Joerg
• Belli Paolo

Classifications

• H02K7/00

  Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines · CPC title

• H02K19/10

  for multi-phase current · CPC title

• F04B15/06

  for liquids near their boiling point, e.g. under subnormal pressure · CPC title

• H02P29/50

  Reduction of harmonics · CPC title

• H02P5/747 Primary

  mechanically coupled by gearing · CPC title