Avoidance of torsional excitations in converter-controlled compressor runs
View Patent ↗A machine has a rotor and includes a converter-controlled drive and a working machine, wherein the drive and the working machine are connected such that a torque is transmitted. A frequency converter is electrically connected to the drive. The frequency converter is embodied such that in a Campbell diagram intersection points are based on the natural torsional frequency of the rotor and V-shaped symmetrical straight lines of the inter-harmonic exciter frequency for output frequencies. The output frequencies are grouped into a plurality of concentration ranges based upon a rotational speed of the machine, wherein each concentration range comprises output frequencies which are close to one another and which respectively have a common output point on the abscissa of the Campbell diagram. Each concentration range defines a blocking range, wherein the machine has an operating rotational speed range which lies outside the blocking ranges.
1. A machine, comprising:
a rotor,
a converter-controlled drive with a variable rotational frequency,
a working machine, wherein the drive and the working machine are connected to one another such that a torque is transmitted,
a frequency converter which is electrically connected to the drive and converts input frequencies to output frequencies,
wherein the frequency converter is embodied such that in a Campbell diagram, relating to the machine, intersection points result from
the natural torsional frequency of the rotor and
V-shaped symmetrical straight lines of the inter-harmonic exciter frequency for the output frequencies,
wherein the output frequencies are grouped into a plurality of concentration ranges based upon a rotational speed of the machine,
wherein each concentration range comprises output frequencies which are close to one another and which respectively have a common output point on the abscissa of the Campbell diagram,
wherein upper and lower limits of each concentration range is defined by an intersection point of
a lowest and/or second lowest and/or third lowest natural torsional frequency of the rotor and
two straight lines of a pair of the inter-harmonics of the first order of the concentration range,
wherein each concentration range defines a blocking range, and
wherein the machine has an operating rotational speed range which lies outside the blocking ranges.
2. The machine as claimed in claim 1 , wherein the drive comprises a number of pole pairs which, together with a motor feeding frequency range, define the operating rotational speed range which lies outside the blocking ranges.
3. The machine as claimed in claim 1 , wherein a transmission for transmitting the rotational speed of the drive to a rotational speed of the working machine acts between the drive and the working machine.
4. The machine as claimed in claim 3 , wherein the rotational speed of the working machine is higher than the rotational speed of the drive.
5. The machine as claimed in claim 1 , wherein the frequency converter is a current intermediate-circuit converter.
6. The machine as claimed in claim 1 , wherein the frequency converter is a voltage converter.
7. The machine as claimed in claim 1 , wherein the drive is a synchronous motor.
8. The machine as claimed in claim 1 , wherein the drive is an asynchronous motor.
9. The machine as claimed in claim 1 , wherein a maximum absorption capacity of the drive is at least one megawatt.
10. The machine as claimed in claim 1 , wherein the working machine is a turbo-machine.
11. The machine as claimed in claim 1 , wherein the working machine is a turbo compressor.
12. A method of operating a machine with a rotor, comprising:
providing a converter-controlled drive with a variable rotational frequency and a working machine,
connecting the drive and the working machine such that a torque is transmitted,
connecting electrically a frequency converter to the drive, wherein the converter converts input frequencies to output frequencies,
wherein the converter is embodied such that in a Campbell diagram, relating to the machine, intersection points are based on
the natural torsional frequency of the rotor and
V-shaped symmetrical straight lines of an inter-harmonic exciter frequency for the output frequencies,
wherein the output frequencies are grouped into a plurality of concentration ranges based upon a rotational speed of the machine,
wherein each concentration range comprises output frequencies which are close to one another and which respectively have a common output point on the abscissa of the Campbell diagram,
wherein upper and lower limits of each concentration range is defined by an intersection point of
a lowest and/or second lowest and/or third lowest natural torsional frequency of the rotor and
two straight lines of a pair of the inter-harmonics of the first order of the concentration range,
wherein each concentration range defines a blocking range, and
wherein the machine has an operating rotational speed range which lies outside the blocking ranges.