Active magnetic bearings for the identification and fault diagnosis in turbomachinery

Aenis, Martin; Knopf, Eric; Nordmann, Rainer

doi:10.1016/s0957-4158(02)00009-0

Cited by 54 publications

(21 citation statements)

References 2 publications

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“…These new set points are supplied to the AMB controller; the system is again interrogated, and MPM coordinates (29.73, 2.94) µm result via Equation (8). The error for the second iteration becomes: Table 5 shows the results of repeating the procedure for multiple iterations.…”

Section: Of 17mentioning

confidence: 99%

“…Operational speeds of 10,000, 11,000 and 14,000 rpm were considered. Similar to [6], Aenis et al [8] use AMBs to measure frequency responses for a centrifugal pump. An i-s (current-displacement) force measurement method using an inboard and outboard AMB is compared to results obtained from a reluctance network approach and a flux-based method requiring up to eight Hall sensor probes.…”

Section: Literature Reviewmentioning

confidence: 99%

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A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

2017

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Inherent in every Active Magnetic Bearing (AMB) are differences between the expected geometric axes and the actual magnetic axes due to a combination of discrepancies, including physical variation from manufacturing tolerances and misalignment from mechanical assembly, fringing and leakage effects, as well as variations in magnetic material properties within a single AMB. A method is presented here for locating the magnetic axes of an AMB that will facilitate the accurate characterization of the bearing air gaps for potential improvement in field tuning, performance analyses and certain shaft force measurement techniques. This paper presents an extension of the application of the bias current perturbation method for the determination of the magnetic center to the determination of magnetic axes for the further development of accurate current-based force measurement techniques.

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Section: Of 17mentioning

confidence: 99%

Section: Literature Reviewmentioning

confidence: 99%

A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

2017

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“…In the joint-inputoutput approach, the transfer function is estimated with the reference signal, and both the plant input and output are considered as outputs. It is pointed out that direct identification has provided accurate models for controller design of an AMB system in several papers Aenis et al (2002), Smirnov (2012), Vuojolainen et al (2016), Jastrzebski et al (2016b), and Wroblewski et al (2012), and therefore, the same approach is considered here. Moreover, the empirical transfer function estimation (ETFE) is used for the transfer function identification in this paper.…”

Section: Identification Of An Active Magnetic Bearing Systemmentioning

confidence: 99%

“…Accurate models obtained by system identification are needed in order to design high-performance controllers (Noshadi et al, 2016), and they have an increasingly important role for diagnostic (Schuhmann et al, 2012) and monitoring purposes (Quinn et al, 2005), (Aenis et al, 2002), (Tiwiri and Chougale, 2014). A common choice for the excitation signal is a sine-wave-based spectrally rich signal, such as a multisine or swept sinusoid signal with a frequency content covering the desired frequency bands.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Excitation Signals in Active Magnetic Bearing System Identification

Vuojolainen¹,

Nevaranta²,

Jastrzębski³

et al. 2017

MIC

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Active magnetic bearings (AMBs) offer frictionless suspension, vibration insulation, programmable stiffness, and damping, among other advantages, in levitated rotor applications. However, AMBs are inherently unstable and require accurate system models for the high-performance model-based multi-input multi-output control of rotor position. Control electronics with high calculation capacity and accurate sensors of AMBs provide an opportunity to implement various identification schemes. A variety of artificial excitation signal-based identification methods can thus be achieved with no additional hardware. In this paper, a selection of excitation signals, namely the pseudorandom binary sequence (PRBS), chirp signal, multisine, and stepped sine are presented, applied, and compared with the AMB system identification. From the identification experiments, the rotor-bearing system, the inner current control loop, and values of position and current stiffness are identified. Unlike recently published works considering excitation-based identification of AMB rotor systems, it is demonstrated that identification of the rotor system dynamics can be carried out using various well-established excitation signals. Application and feasibility of these excitation signals in AMB rotor systems are analyzed based on experimental results.

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“…Similar to [13], Aenis et al [15] use AMBs to measure frequency responses for a centrifugal pump. An i-s force measurement method using an inboard and outboard AMB is compared to results obtained from a reluctance network approach and a flux base method requiring up to eight Hall sensor probes.…”

Section: Literature Reviewmentioning

confidence: 99%

A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

Spangler¹,

Prins²,

Kasarda³

2017

Preprint

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Inherent in every Active Magnetic Bearing (AMB) are differences between the expected geometric axes and the actual magnetic axes due to a combination of discrepancies, including physical variation from manufacturing tolerances and misalignment from mechanical assembly, fringing and leakage effects, as well as variations in magnetic material properties within a single AMB. A method is presented here for locating the magnetic axes of an AMB that will facilitate the accurate characterization of the bearing air gaps for potential improvement in field tuning, performance analyses and certain shaft force measurement techniques. This paper presents an extension of the application of the bias current perturbation method for the determination of the magnetic center [4] to the determination of magnetic axes for the further development of accurate current-based force measurement techniques [1].

show abstract

Active magnetic bearings for the identification and fault diagnosis in turbomachinery

Cited by 54 publications

References 2 publications

A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

Comparison of Excitation Signals in Active Magnetic Bearing System Identification

A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

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