Fault-tolerant control of three-pole active magnetic bearing

Agarwal, Praveen Kumar; Chand, Satish

doi:10.1016/j.eswa.2009.05.052

Cited by 26 publications

(9 citation statements)

References 17 publications

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“…In the past decade, different design approaches have been used for the AMBs. These approaches relate to the controller design, sensing techniques and eddy current effects, and proposed solutions have been given for a variety of problems and their effects on the rotating systems stability in both industrial systems [4][5][6][7][8] and biomedical applications. 9 A full fault diagnosis for AMBs and rotor systems to monitor the closed-loop operation and to analyse fault patterns on-line in case any malfunction occurs has been proposed by Tsai et al 10 The design of a smart rotating machine involves the integration of controllable bearings, actuators and sensors to measure a defined set of physical variables, an on-line adaptive controller, a control algorithm to achieve the desired performance and an algorithm to re-configure the system in the event of faults.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design of an active hydromagnetic journal bearing

Farmakopoulos

Nikolakopoulos

Papadopoulos

2012

Proceedings of the Institution of Mechanical Engineers, Part J:

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An active hydromagnetic journal bearing is designed and presented in this study, which is a new and innovative type of hybrid journal bearing. The proposed new mechatronic smart device has a common bearing shell that contains the two parts of the bearing, which is an attempt to combine the advantages of both types of bearings to overcome their drawbacks and give rise to new possibilities for instability control, increased load-carrying capacity, diagnostics of the rotor system, etc. The active hydromagnetic journal bearing should operate as either a hydrodynamic, active magnetic or hybrid journal bearing, depending on the needs of the rotating machinery. The hydrodynamic lubrication is developed in the inner bearing surface, and the electromagnets of the magnetic bearing are placed outside its outer surface. The active hydromagnetic journal bearing is designed with the appropriate clearance, so that both the hydrodynamic and magnetic bearings can operate. The suitable operational regions for the active hydromagnetic journal bearing are calculated and presented as a combination of the optimum ratio between the air gap and the clearance. Additionally, a simulation code using the two-dimensional finite element method (ANSYS) is developed to simulate the performance of the magnetic component of the active hydromagnetic journal bearing, and the ANSYS software is used to obtain a solution for the hydrodynamic pressure field. The dynamic characteristics of the hybrid journal bearing in terms of the stiffness and damping coefficients versus the Sommerfeld number are calculated and presented. In the hybrid bearing operation, the corresponding stiffness and damping coefficients are used to simulate the hydromagnetic bearing dynamic behaviour. Each hybrid coefficient consists of two parts; the hydrodynamic and the magnetic part. When the operation is purely hydrodynamic, the magnetic parts of the dynamic coefficients are zero and vice versa, whereas both parts are present in the hybrid operation mode.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design of an active hydromagnetic journal bearing

Farmakopoulos

Nikolakopoulos

Papadopoulos

2012

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…An electromagnetic device which levitates a rotor by controlling the attractive electromagnetic forces can be seen as an active magnet bearing (AMB). AMBs are used in the industry due to the fact that there is no mechanical contact between the parts, no lubrication requirements and high-precision operation (Agarwal et al, 2009;Gouws et al, 2011;Kim et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Impact of frequency switching on the efficiency of a fully suspended active magnetic bearing system

Gouws

2012

Int. J. Phys. Sci.

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Due to the rising energy (and electricity) cost it is essential that an active magnetic bearing (AMB) system is operated as efficiently as possible. Frequency switching caused by an external source can cause an AMB system to operate at a higher than expected energy level and lower than expected efficiency. The purpose of this paper is therefore to investigate the impact of frequency switching (caused by an external source) on the efficiency of a fully suspended AMB system. The shaft of the fully suspended AMB system for this project is mechanically connected and driven by an induction motor and the vertical and horizontal displacements of the driven unit are controlled by means of PID controllers. The model of the fully suspended AMB system with the external fault and the process diagram used for frequency extraction during the fault condition is presented. It is shown that the efficiency of the fully suspended AMB system can be improved by optimizing the controller performance during the external fault condition.

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“…These bearings are considered superior over conventional bearings because the friction losses are significantly reduced because of contactless operation. The bearings can also produce high speed, are able to eliminate lubrication and the operation will be quiet (Agarwal and Chand, 2009). Magnetic bearings are increasingly used in industrial machines such as compressors, turbines, pumps, motors and generators.…”

Section: Introductionmentioning

confidence: 99%

Observer-based feedback for the magnetic levitation system

Baranowski

Piątek

2011

Transactions of the Institute of Measurement and Control

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Control of active magnetic bearings is an important area of research. The laboratory magnetic levitation system can be interpreted as a model of a single axis of bearings and is a useful testbed for control algorithms. The mathematical model of this system is highly non-linear and requires careful analysis and identification. The system is observable from position measurements as long as the electromagnet is powered as shown during the research. Practically measurable signals are the position and the coil current. The velocity that is necessary for any stabilizing control usually is obtained by numerical differentiation of the position. A more sophisticated approach is to estimate the velocity with an observer. Efficient observer types for this system are high-gain and non-linear reduced observers. The velocity estimated by an observer can be effectively used instead of a derivative in PID control of the position. Such an approach substantially improves control quality and extends the range of system’s stable operation. Even greater improvement is introduced by the addition of the non-linear feedforward to the control structure. The best results, provided the model parameters are correctly identified, are obtained with a control system consisting of the PID controller, the high-gain observer and the non-linear feedforward.

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Fault-tolerant control of three-pole active magnetic bearing

Cited by 26 publications

References 17 publications

Design of an active hydromagnetic journal bearing

Design of an active hydromagnetic journal bearing

Impact of frequency switching on the efficiency of a fully suspended active magnetic bearing system

Observer-based feedback for the magnetic levitation system

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