Modeling, design and control of a flexible rotor supported by active magnetic bearings

Štimac, Goranka; Braut, Sanjin; Žigulić, Roberto; Skoblar, Ante

doi:10.1533/9780857094537.6.419

Cited by 3 publications

(4 citation statements)

References 4 publications

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“…Although the limited impact of actuators can be noticed, the observed mechanical configuration is the result of an optimization procedure and has proved to be an acceptable solution in this research. Moreover, successful passing through the first critical speed further proves the validity of the chosen system configuration (Štimac et al , 2012).…”

Section: Dynamic Analysesmentioning

confidence: 56%

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Modeling and experimental verification of a flexible rotor/AMB system

Štimac

Braut

Bulić

et al. 2013

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -In this paper, the aim is to present a modeling strategy for a flexible rotor/active magnetic bearing (AMB) system with non-collocation. Special attention is paid to the vibration reduction and the stable passage through the first critical speed. Design/methodology/approach -The finite element method based on Euller-Bernoulli beam theory is applied in the formulation of the rotor model. Since rotor/AMB systems are complex mechatronic systems, reduced order approach is used in the control system design. This study applies the modal decomposition method and the modal truncation method, thus retaining the lower order bending modes. The obtained numerical results are compared with the measured open loop frequency responses and the existing differences are compensated in order to obtain accurate numerical model. Findings -Frequency response of the entire system model (flexible shaft, actuators, power amplifiers and sensors) with amplitudes expressed in rotor lateral displacements can be verified by the measured frequency responses. The deviations in the amplitude and phase diagrams are then successfully corrected using the appropriate model modifications. Practical implications -The results of this research find direct applications in flexible rotors supported by AMBs, e.g. high speed spindles, turbo molecular pumps, flywheel energy storage systems, etc. The presented procedure can be especially valuable in the design of model based controllers. Originality/value -An AMB system model is developed and presented in this paper, in conjunction with a systematic description of an efficient procedure for the elimination of the typical mismatches between the simulation and experiment. Firstly, rotor/AMB test rig is stabilized with an appropriately tuned PID controller and an open loop frequency response is obtained for such a system. This response is then compared to corresponding simulation results for which mismatches are identified and eliminated thus yielding an accurate model of the system. COMPEL 32,4 1244 1. Introduction Active magnetic bearings (AMBs) present an alternative to conventional mechanical bearings in a variety of rotating machines, such as turbo molecular pumps, flywheels, machine tool spindles, etc. Their unique advantages, such as complete elimination of oil lubrication systems, absence of mechanical wear, low maintenance costs, programmable stiffness and damping, follow directly from their contactless suspension principle.Nevertheless, AMB systems are multivariable systems which require properly tuned feedback loops in order to ensure stable rotor suspension. Control of AMBs has been studied in many papers. The papers by Siegwart et al. (1991) and Lei and Palazzolo (2008) utilized linear PID controllers with associated filters, while papers Jastrzebski et al. (2010), Nonami and Ito (1996) and Schönhoff et al. (2000) deal with more advanced control strategies. If the rotor operates in the subcritical frequency range, a point mass or a rigid body model can be used to model the shaft. However, fo...

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Section: Dynamic Analysesmentioning

confidence: 56%

“…The mechanical configuration of the flexible rotor considered in this paper is shown in Figure 2. It is chosen based on the procedure carried out by Štimac et al (2012). The two rotor parts (AMB A and AMB B) are mounted onto the flexible shaft.…”

Section: Design Overviewmentioning

confidence: 99%

Modeling and experimental verification of a flexible rotor/AMB system

Štimac

Braut

Bulić

et al. 2013

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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“…This allows for several advantages over standard bearings, such as increased efficiency, excellent reliability, and the ability to operate in harsh environments [2]. However, these benefits come at the cost of increased complexity and the need for precise control and monitoring of magnetic forces [3]. A digital twin is a virtual representation of a physical asset or system that monitors, analyzes, and optimizes performance [4].…”

Section: Introductionmentioning

confidence: 99%

Modeling of a Digital Twin for Magnetic Bearings

Taha

2023

Applied Sciences

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As an essential enabling technology to realize advanced concepts such as digitization, intelligence, and service, information technology plays a critical role in shaping modern society and driving innovation across various industries and domains. The concept of the digital twin is attracting attention from academics and industry, and how to apply it in various fields. In this paper, the performance of the magnetic bearing system may be simulated in real-time using a digital twin, especially the resulting vibration from the unbalanced rotor mass, which caused a drop in performance and a high risk of system instability and potential safety accidents. It is suggested to use a model-data combination driven digital twin model to examine its dynamic characteristics and vibration mechanism. The vibration data of the magnetic bearing was collected through experiments and compared with the data derived from the simulation results. The efficiency of the suggested strategy is demonstrated by confirming that digitally anticipated vibration signals are consistent with physical space measurements. The result shows that the fine digital twin geometric model of magnetic bearing is more consistent with the actual operation. By allowing the identification of problems before they become critical, using a digital twin may increase the dependability of magnetic bearings while reducing the possibility of unexpected downtime or failures.

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“…In [20] they examine the performance of a flexible rotor/AMB system in the case of PID and PI-D control, both in combination with NOTCH filters. Using PID control, Štimac et al have proposed a vibrationdamping model using magnetic forces for a flexible rotor supported in an AMB [21]. Numanoy and Srisertpol also use PID controllers to reduce vibrations of the rotor/AMB system [7].…”

Section: Introductionmentioning

confidence: 99%

The annulling of the sudden appearance of an unbalance in rotary machines by using active magnetic bearings

Tomović,

Damjanović,

Tomović

et al. 2023

Eng. rev. (Online)

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The application of magnetic bearings has become more frequent during the last 20 years and represents a significant aspect of improvements in the construction of machines with rotary motion. With the advancement of technology, the number of applications in which magnetic bearings have found their application is increasing. In this paper, it is shown how the effect of magnetic forces can annul the negative influence of unbalance, which suddenly appeared in a rotor supported in active magnetic bearings. Such cases may occur in operation due to breakage and rotor parts falling off (e.g., fan blades), which will lead to a sudden change in the mass balance of the rotor system and dislocation of the centre of mass in relation to the geometric centre of the rotor. In the paper, a mathematical model of the dynamic behaviour of a rigid rotor in active magnetic bearings was developed. The model is nonlinear and has five degrees of freedom and can only be solved numerically. The Newmark beta method and the Newton-Raphson method were used to solve the system of nonlinear differential equations. The results of the simulation showed the advantages of using active magnetic bearings for annulling sudden occurrences of unbalance in rotary machines.

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Modeling, design and control of a flexible rotor supported by active magnetic bearings

Cited by 3 publications

References 4 publications

Modeling and experimental verification of a flexible rotor/AMB system

Modeling and experimental verification of a flexible rotor/AMB system

Modeling of a Digital Twin for Magnetic Bearings

The annulling of the sudden appearance of an unbalance in rotary machines by using active magnetic bearings

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