Practical Controller Design for Rotors on Magnetic Bearings by Means of an Efficient Simulation Tool

Schmied, Joachim; Kosenkov, Alexander

doi:10.1115/gt2013-95075

Cited by 10 publications

(5 citation statements)

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“…Therefore, the flexible eigen-frequencies can be approximately found independent of the control structure. How the flexible body modes are stabilized by the phase shift of the controller is given in [21]. For structures where the stiffness of the magnetic bearing cannot be neglected, the finite element method in combination with the dynamic simulation of the control structure can be used.…”

Section: Modeling Of a 5-dof Amb Systemmentioning

confidence: 99%

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Control of Active Magnetic Bearings in Turbomolecular Pumps for Rotors with Low Resonance Frequencies of the Blade Wheel

Hutterer

Schrödl

2017

Lubricants

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Rotors with high gyroscopic effects and low resonance frequencies caused by the blade wheel (blade frequencies) can lead to stabilization problems in the application field of turbomolecular pumps. If such a rotor is stabilized by active magnetic bearings, the control structure could be destabilized by the splitting up of the rigid body eigen-frequencies caused by the gyroscopic effect. The control structure of the magnetic bearings can also destabilize the eigen-modes caused by the blade wheel, if the gain of the control structure is too high in the range of the eigen-frequencies of the blade wheel. To deal with the problem of the gyroscopic effect, a decoupling and compensation method was developed based on the inverse dynamics of the rigid body rotor. The gain of the control structure in the range of the blade frequencies is decreased using a Kalman filter. To increase the damping of the system, the predicted states of the linear magnetic bearing model using a Kalman filter are applied instead of the sampled values of the sensors directly. For the decoupled structure, PID controllers are used for stabilization. The functionality of the control structure is verified by a measurement of the current and position signal using the Kalman states and the sensor values. The robustness and performance in the frequency range are verified using the sensitivity and compliance function.

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Section: Modeling Of a 5-dof Amb Systemmentioning

confidence: 99%

“…The flexible body modes can be stabilized using second order filters. The phase φ in the region of the eigen-frequencies is of great significance [21]. For flexible body modes, the controller provides damping at phase ranges of:…”

Section: Stabilizing the Bending Modesmentioning

confidence: 99%

Control of Active Magnetic Bearings in Turbomolecular Pumps for Rotors with Low Resonance Frequencies of the Blade Wheel

Hutterer

Schrödl

2017

Lubricants

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“…Electromagnetic systems (Fig. 5, left) provide the possibility of contact-free support and thus reduce wear and eliminate the need for lubrication, which is advantageous for use in hermitically sealed compressors [21]. If they are used just for vibration reduction only, due to their larger displacements and the possibility of contactless actuation, they can be placed outside the bearing planes, which usually lead to an increased effect of the modes of the system.…”

Section: Smart'13: Smart Materials and Structuresmentioning

confidence: 99%

Mechatronic System Integration Potential for Different Applications

Rinderknecht

Strah

2013

AMR

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Starting with some general and historical perspective, mechatronics is placed in the technological field map as a multidisciplinary discipline. The considered advantages of mechatronic systems are exposed from the human perspective, which enables the consideration of the social impact of this technological discipline. Due to the multidisciplinary character of mechatronics, the integration issues including synergetic effects consider both geometrical and functional aspects. The same reason provides a very large variety of different solutions to fulfill a certain functionality. Choosing an appropriate solution for a specific application is done using systematic methods which shape this problem to an optimization problem. General statements are illustrated with different application examples.

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“…Figura 3.4 -Principais componentes do sistema rotativo suportado por MMA's3.3 Modelo do RotorPara que o projeto de controladores de máquinas rotativas suportadas por MMA's seja bem sucedido, a análise dos modos e das frequências naturais do rotor na condição livre-livre, nas fases iniciais do seu desenvolvimento, é imprescindível (SCHIMIED;KOSENKOV, 2013;SCHWEITZER;MASLEN, 2009). Com base nesta análise, pode-se avaliar quais modos estão localizados tanto dentro da faixa de velocidades de operação da máquina quanto na banda de frequência do controlador, haja vista que, os valores típicos de rigidez fornecidos pelos mancais magnéticos são relativamente baixos.…”

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“…3.12, sobrepõe-se os 04 primeiros modos de flexão do rotor às posições dos sensores e dos MMA's, onde é possível notar que o controle é do tipo não colocado, pois as posições dos sensores não coincidem com as dos seus respectivos atuadores. Além disso, esta figura também permite avaliar a controlabilidade e a observabilidade do sistema rotativo(SCHIMIED;KOSENKOV, 2013;SCHWEITZER;MASLEN, 2009). Neste sentido, caso algum modo possua um nó coincidente com um sensor, ele não é observável.…”

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Controle modal de rotores com mancais magnéticos: Projeto Robusto

Borges¹

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The present work is devoted to the development of a Systematic Approach for the Robust Design of an Active Modal Controller applied to Supercritical Rotors supported by Magnetic Bearings. For this purpose, all the steps involved in the design of a robust controller based on multimodel eigenstructure assignment technique were discussed from a complete and detailed point of view. The first step was the conception of a numeric/computer model in MATLAB/SIMULINK environment, based on the specifications provided by the test rig manufacturer. Following, this model was tested through an experimental validation process, resulting a mathematical model that represents closely the dynamic behavior of the actual physical system. Next, the most critical uncertainties of the system were incorporated into the nominal model by using the Linear Fractional Transformation (LFT) approach. The first stage of the controller synthesis process itself was the specification of all design requirements. Then, all the phases involved in the process of the multimodel eigenstructure assignment are addressed in detail, starting from the determination of the plant dominant poles until the model based analysis of the system stability and performance. In this way, the potential of the methodology proposed was investigated and possible design problems were anticipated. It should be highlighted that the system stability was assessed from two different viewpoints, namely the standard ISO 14839-3 and the structured singular values (μ-analysis). In the same way, the performance of the controller was evaluated through the analysis of its closed loop Transfer Functions and by investigating the unbalance response of the rotating system. The unbalance response was conducted according to the API 684 technical standard guidelines and the vibration severity was classified as based on ISO 14839-2 criteria. Therefore, both the stability margin and performance of the controller were experimentally assessed which, in accordance with the simulations, demonstrated that the controller design was successful. Based upon these results, it is possible to state that the main contribution of the presente work was the sistematization of the Robust Design of Active Modal Controller applied to Supercritical Rotors supported by Magnetic Bearings. In addition, anothers relevant contributions should also be highlighted, namely: development of representative models of rotating systems for application in active control plants, determination and implementation of active control architectures with real possibility of application in industry, design and characterization of controllers for active magnetic bearings with focus in modal control. Finally, it is worth mentioning that for all presented investigations, comparisons between the two architectures of the controller, namely: the modal controller and the PI controller were performed accordingly.

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Practical Controller Design for Rotors on Magnetic Bearings by Means of an Efficient Simulation Tool

Cited by 10 publications

References 0 publications

Control of Active Magnetic Bearings in Turbomolecular Pumps for Rotors with Low Resonance Frequencies of the Blade Wheel

Control of Active Magnetic Bearings in Turbomolecular Pumps for Rotors with Low Resonance Frequencies of the Blade Wheel

Mechatronic System Integration Potential for Different Applications

Controle modal de rotores com mancais magnéticos: Projeto Robusto

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