Fault tolerant homopolar magnetic bearings with flux invariant control

Na, Uhn Joo

doi:10.1007/bf02915981

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Due to the current distribution matrix reflecting the intrinsic properties of the magnetic bearing, the more physical characteristics of the system included in the process of solving current distribution matrix, the better the performance of the corresponding controller will be. Therefore, in the face of magnetic leakage, eddy current, and the reluctance of the ferromagnetic material path factors of magnetic bearing systems, Na and Palazzolo [10][11][12] introduced a compensation coefficient into the process of solving the current distribution matrix. Considering that the rotor vibrates with a tiny displacement near the equilibrium position, X. Cheng and Baixin Cheng [13] proposed a method that included the rotor at nonequilibrium positions to calculate the current distribution matrix, and the simulation results indicated that the electromagnetic force was closer to the desired electromagnetic force, while the corresponding fault-tolerant controller was tested by simulation [14].…”

Section: Introductionmentioning

confidence: 99%

Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures

Cheng

Song

et al. 2022

Sensors

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At present, magnetic bearings are a better energy-saving choice than mechanical bearings in industrial applications. However, there are strongly coupled characteristics in magnetic bearing–rotor systems with redundant structures, and uncertain disturbances in the electrical system as well as external disturbances, and these unfavorable factors degrade the performance of the system. To improve the anti-interference performance of magnetic bearing systems, this paper proposes the inverse of the current distribution matrix W−1 meaning that the active disturbance rejection control simulation model can be carried out without neglecting the current of each coil. Firstly, based on the working mechanism of magnetic bearings with redundant structures and the nonlinear electromagnetic force model, the current and displacement stiffness models of magnetic bearings are established, and a dynamic model of the rotor is constructed. Then, according to the dynamic model of the rotor and the mapping relationship between the current of each coil and the electromagnetic force of the magnetic bearing, we established the equivalent control loop of the magnetic bearing–rotor system with redundant structures. Finally, on the basis of the active disturbance rejection control (ADRC) strategy, we designed a linear active disturbance rejection controller (LADRC) for magnetic bearings with redundant structures under the condition of no coil failure, and a corresponding simulation was carried out. The results demonstrate that compared to PID+current distribution control strategy, the LADRC+current distribution control strategy proposed in this paper is able to effectively improve the anti-interference performance of the rotors supported by magnetic bearings with redundant structures.

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Section: Introductionmentioning

confidence: 99%

Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures

Cheng

Song

et al. 2022

Sensors

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“…They defined a compensation coefficient to make up for errors. Na [ 15 , 16 ] designed magnetic-levitated bearing fault-tolerant controllers based on force invariance or flux invariance theory. However, the work mentioned above is related to the heteropolar magnetic-levitated bearings.…”

Section: Introductionmentioning

confidence: 99%

Fault-Tolerant Control of Magnetically-Levitated Rotor with Redundant Structures Based on Improved Generalized Linearized EMFs Model

Cheng

Song

et al. 2021

Sensors

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Fault tolerance is one of the effective methods to improve the reliability of magnetic bearings, and the redundant magnetic bearing provides a feasible measure for fault-tolerant control. The linearization and accuracy of the electromagnetic force (EMF) from the redundant structures is crucial for designing fault-tolerant controllers. In the magnetic bearing with a redundant structure, the current distribution matrix W is an important factor that affects the accuracy of EMF. In this paper, we improved the accuracy of the EMF model and took the eight-pole symmetrical radial magnetic bearing as the research object. The corresponding displacement compensation matrices have been calculated for the different coils that fail in the magnetic bearing while the rotor is at the non-equilibrium position. Then, we propose a fault-tolerant control strategy that includes displacement compensation. The rigid body dynamics model of the rotor, supported by magnetic bearings with redundant structures, is established. Moreover, to verify the effectiveness of the proposed control strategy, we combined the rigid body dynamics model of the rotor with a fault-tolerant control strategy, and the corresponding simulation has been carried out. In the case of disturbance force and some coils fail in magnetic bearing and compared with the fault-tolerant control that absents the displacement compensation factors. The simulations demonstrate the disturbance rejection of magnetically levitated rotor system can be enhanced. The robustness of the rotor has been improved with the fault-tolerant control strategy proposed in this paper.

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“…Magnetic bearings are the core part of high-speed electrospindles and directly affect their properties. The most common magnetic bearings used to support magnetically suspended motorized spindles are DC magnetic bearings [1][2][3][4][5]. In terms of cost savings and power consumption, AC magnetic bearings and hybrid magnetic bearings (HMBs) have obvious advantages compared with other magnetic bearings [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis and Full Prediction Model of a 5-DOF Motorized Spindle

et al. 2017

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Abstract:The cost and power consumption of DC power amplifiers are much greater than that of AC power converters. Compared to a motorized spindle supported with DC magnetic bearings, a motorized spindle supported with AC magnetic bearings is inexpensive and more efficient. This paper studies a five-degrees-of-freedom (5-DOF) motorized spindle supported with AC hybrid magnetic bearings (HMBs). Most models of suspension forces, except a "switching model", are quite accurate, but only in a particular operating area and not in regional coverage. If a "switching model" is applied to a 5-DOF motorized spindle, the real-time performance of the control system can be significantly decreased due to the large amount of data processing for both displacement and current. In order to solve this defect, experiments based on the "switching model" are performed, and the resulting data are analyzed. Using the data analysis results, a "full prediction model" based on the operating state is proposed to improve real-time performance and precision. Finally, comparative, verification and stiffness tests are conducted to verify the improvement of the proposed model. Results of the tests indicate that the rotor has excellent characteristics, such as good real-time performance, superior anti-interference performance with load and the accuracy of the model in full zone. The satisfactory experimental results demonstrate the effectiveness of the "full prediction model" applied to the control system under different operating stages. Therefore, the results of the experimental analysis and the proposed full prediction model can provide a control system of a 5-DOF motorized spindle with the most suitable mathematical models of the suspension force.

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Fault tolerant homopolar magnetic bearings with flux invariant control

Cited by 6 publications

References 13 publications

Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures

Active Disturbance Rejection Control in Magnetic Bearing Rotor Systems with Redundant Structures

Fault-Tolerant Control of Magnetically-Levitated Rotor with Redundant Structures Based on Improved Generalized Linearized EMFs Model

Experimental Analysis and Full Prediction Model of a 5-DOF Motorized Spindle

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