Unbalance compensation of a magnetically levitated rotor for the whole operating range

Hutterer, Markus; Schrcodl, Manfred

doi:10.1109/icmech.2017.7921108

Cited by 6 publications

(11 citation statements)

References 4 publications

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“…The advantages of calculating the Fourier transform in complex coordinates is that a single spectrum provides the same information provided by q y and q z together. For a given p, the peaks from r n can be conveniently stacked to be equivalent to the output vector y d from (13).…”

Section: Modal Estimationmentioning

confidence: 99%

“…Other rotodynamic feedforward strategies applied to rotating machinery can be found in the literature. [11][12][13] Although the standard single unbalance compensation is quite relevant, calculating the compensation force is not so straightforward in case of multiple planes or distributed forces. Faulting components usually tend to excite the rotors in multiple harmonics, not only in synchronous (forward) but also in backward direction.…”

Section: Introductionmentioning

confidence: 99%

“…Still, even with a simpler calculation, the CC method presented slightly better performance than the finite impulse response method. Other rotodynamic feedforward strategies applied to rotating machinery can be found in the literature …”

Section: Introductionmentioning

confidence: 99%

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Feedforward Rotor Fault Compensation

Cavalca

Markert

2020

Struct Control Health Monit

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When damaged, it is not unusual to observe nonlinear responses in previously linear structures. Specifically, in rotating machinery context, unbalance, misalignment, bearing, and shaft damage occur during operation, and their responses arise as a combination of multiple modes and harmonics. These vibration effects are undesirable and, besides compromising the system performance, can propagate or generate further faults. In practice, the machine cannot be simply stopped for repairs, and a method for provisory attenuating such problems is desirable. The fault effects can be approximated by a set of loads distributed along the healthy rotor linear model approximation. Intuitively, one can also estimate counteractive forces to mitigate the fault symptoms. Therefore, this work proposes a simple feedforward approach to detect and compensate fault effects at multiple harmonics in rotors. The compensating force is calculated to minimize the least square modal difference between healthy and faulty rotor. A test rig is operated in distinct conditions to demonstrate and validate the method highlighting different fault symptoms (unbalance, misalignment, and shaft bow).

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Section: Modal Estimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feedforward Rotor Fault Compensation

Cavalca

Markert

2020

Struct Control Health Monit

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“…Another connection of GNF into the closed loop allows the rotor to spin around its geometric axis. These two approaches are compared in [ 11 ] and other modifications of GNF can be found in, e.g., [ 12 , 13 , 14 ]. The advantage of GNF is that it does not require an AMB rotor system model and does not increase the AMB controller order significantly.…”

Section: Introductionmentioning

confidence: 99%

“…In [ 10 ], a transformation matrix is used in the GNF circuit to tune the closed loop stability. In [ 11 ], the transformation matrix is replaced by a phase-shift angle which simplifies the stability setting.…”

Section: Introductionmentioning

confidence: 99%

A Vibration Sensor-Based Method for Generating the Precise Rotor Orbit Shape with General Notch Filter Method for New Rotor Seal Design Testing and Diagnostics

Kalista

Liška

Jakl

2021

Sensors

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Verification of the behaviour of new designs of rotor seals is a crucial phase necessary for their use in rotary machines. Therefore, experimental equipment for the verification of properties that have an effect on rotor dynamics is being developed in the test laboratories of the manufacturers of these components all over the world. In order to be able to compare the analytically derived and experimentally identified values of the seal parameters, specific requirements for the rotor vibration pattern during experiments are usually set. The rotor vibration signal must contain the specified dominant components, while the others, usually caused by unbalance, must be attenuated. Technological advances have made it possible to use magnetic bearings in test equipment to support the rotor and as a rotor vibration exciter. Active magnetic bearings allow control of the vibrations of the rotor and generate the desired shape of the rotor orbit. This article presents a solution developed for a real test rig equipped with active magnetic bearings and rotor vibration sensors, which is to be used for testing a new design of rotor seals. Generating the exact shape of the orbit is challenging. The exact shape of the rotor orbit is necessary to compare the experimentally and numerically identified properties of the seal. The generalized notch filter method is used to compensate for the undesired harmonic vibrations. In addition, a novel modified generalized notch filter is introduced, which is used for harmonic vibration generation. The excitation of harmonic vibration of the rotor in an AMB system is generally done by injecting the harmonic current into the control loop of each AMB axis. The motion of the rotor in the AMB axis is coupled, therefore adjustment of the amplitudes and phases of the injected signals may be tedious. The novel general notch filter algorithm achieves the desired harmonic vibration of the rotor automatically. At first, the general notch filter algorithm is simulated and the functionality is confirmed. Finally, an experimental test device with an active magnetic bearing is used for verification of the algorithm. The measured data are presented to demonstrate that this approach can be used for precise rotor orbit shape generation by active magnetic bearings.

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Modeling and mu-synthesis control of a flexible rotor stabilized by active magnetic bearings including current free control

Hutterer

Schrödl²

2023

Journal of Sound and Vibration

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Unbalance compensation of a magnetically levitated rotor for the whole operating range

Cited by 6 publications

References 4 publications

Feedforward Rotor Fault Compensation

Feedforward Rotor Fault Compensation

A Vibration Sensor-Based Method for Generating the Precise Rotor Orbit Shape with General Notch Filter Method for New Rotor Seal Design Testing and Diagnostics

Modeling and mu-synthesis control of a flexible rotor stabilized by active magnetic bearings including current free control

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