A simple PID controller for a magnetic bearing with four poles and interconnected magnetic flux

2017 ◽  
Author(s):  
Christian Tshizubu ◽  
Jose Andres Santisteban
Keyword(s):  
Magnetic Flux ◽  
Pid Controller ◽  
Magnetic Bearing

Influence of Retainer Bearing Misalignment on the Performance of Active Magnetic Bearing

2012 ◽  
Vol 588-589 ◽  
pp. 141-146 ◽  
Author(s):  
Hong Wei Li ◽  
Wen Tao Yu ◽  
You Peng Fan ◽  
Shu Qin Liu
Keyword(s):  
Pid Controller ◽  
Damping Ratio ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
System Structure ◽  
Design System ◽  
Force Model ◽  
Low Pass ◽  
And Performance ◽  
Low Pass Filters

The retainer bearing will be misaligned for mechanical errors, which leads to the uneven air gap of AMB and affects the performance of AMB. To study this problem, the electric-magnetic force model was built first with the misalignment of retainer bearing. With this model, the influences of the misalignment on the system stiffness, damping and damping ratio of AMB were studied through theory analysis and simulation based on the PID controller with low-pass filters. The study indicates that the system stiffness and damping ratio of AMB employing PID controller will increase with the increase of retainer bearing misalignment. The results provide certain references for the system structure optimum design, system debugging and fault diagnosis and performance improvement of AMB-rotor system.

Rotor Power Losses in Planar Radial Magnetic Bearings — Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density

1998 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with 8 pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.

Nonlinear Vibration in a Vertical Rigid Rotor Supported by the Magnetic Bearing: Case Considering the Delays of Both Electric Current and Magnetic Flux

2007 ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Motoki Sugiyama ◽  
Yasuhiko Sugawara ◽  
Yukio Ishida
Keyword(s):  
Magnetic Flux ◽  
Electric Current ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Nonlinear Phenomena ◽  
Control Force ◽  
Rigid Rotor ◽  
Rotating Speed ◽  
First Order

Active magnetic bearing (AMB) becomes to be widely used in various kinds of rotating machinery. However, as the magnetic force is nonlinear, nonlinear phenomena may occur when the rotating speed becomes higher and delay of control force increases. In this paper, the magnetic force is modeled by considering both the second order delay of the electric current and the first order delay of the magnetic flux, and the AMB force is represented by a power series function of the electric current and shaft displacement. The nonlinear theoretical analysis of the vertical rigid rotor supported by AMB is demonstrated. The effects of the delays and other AMB parameters on the nonlinear phenomena are clarified theoretically and experimentally.

scholarly journals Vibration Reduction of an Overhung Rotor Supported by an Active Magnetic Bearing Using a Decoupling Control System

Machines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 73
Author(s):  
Nitisak Numanoy ◽  
Jiraphon Srisertpol
Keyword(s):  
Pid Controller ◽  
Lateral Force ◽  
Harmonic Excitation ◽  
Magnetic Bearing ◽  
Decoupling Control ◽  
Active Magnetic Bearing ◽  
Central Position ◽  
Operational Conditions ◽  
Run Up ◽  
Overhung Rotors

Overhung rotors are important for use in industrial turbo-machines. The effects of a lateral force can increase as a result of the rotor weight, misalignment, or the operating speed of the suspension system for which the rotor is carrying a transmission connection. In this paper, the reduction of vibration in supported lateral directions by varying control is discussed in a radial active magnetic bearing system (AMBS). An experimental test was conducted on the orbital response of an overhung rotor supported by an AMBS, to provide an alternative for improving precision. To simplify the system design, decoupling was achieved using a PID controller and harmonic disturbance compensator (HDC), which improved the rotating performance of an overhung active magnetic bearing (AMB) rotor system, using a frequency response function (FRF) approach and a description of the overhung rotor during normal operational conditions at unique frequencies. The experimental results show that the precision rotation, due to harmonic excitation of the shaft orbit, can be removed in real time using compensation signals using trigonometry. The compensation criteria for the changed run-up and coast-down consistently helped to maintain the rotational center in a central position. A reduction of up to 55% in vibration amplitude on average was achieved under appropriate conditions, and the significance of the overhung rotor symptoms faults were investigated.

Design of a Highly Integrated Active Magnetic Bearing With Six Coupled Actuators for High Precision Rotation Applications

1999 ◽  
Author(s):  
M. Kümmerle ◽  
B. Aeschlimann ◽  
J. Zoethout ◽  
T. Belfroid ◽  
R. Vuillemin ◽  
...  
Keyword(s):  
High Precision ◽  
Pid Controller ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
The Other ◽  
Axial Forces ◽  
Functional Prototype ◽  
The One ◽  
Contact Free

Abstract This paper presents the design and the implementation of a contact free Active Magnetic Bearing (AMB) for high precision rotation applications. For controlling five Degrees of Freedom (DOF) of the rotor six coupled reluctance force actuators (creating radial and axial forces at the same time) are used. A method for designing the actuators in order to meet the specifications is described. Two different controller schemes using different sensor configurations have been implemented on a functional prototype: On the one hand a conventional decentralized PID controller, on the other hand a more centralized structure.

Improvement of Low Frequency Vibration Isolation Capability of AMB Using a Cascade PID Controller

2018 ◽  
Author(s):  
Yixin Su ◽  
Yanhui Ma ◽  
Yongpeng Gu ◽  
Suyuan Yu ◽  
Gexue Ren
Keyword(s):  
Pid Controller ◽  
Vibration Isolation ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Control Parameters ◽  
Control Loops ◽  
Low Frequency Vibration ◽  
Wide Range

In contrast with traditional mechanical bearing, Active magnetic bearing (AMB) has no friction and lubrication, and its dynamic performance can be adjusted by active control. To isolate low frequency vibration of the rotating machinery under 50Hz, a novel design of cascade PID controller (CPC) with two control loops for AMB is proposed. The main loop is a position loop and the secondary loop is a transmission force loop. According to the theoretical derivations in this study, the CPC controls both the rotor position and the transmission force. Even when the control parameters maintain constant, the dynamic characteristic parameters, equivalent stiffness and equivalent damping, vary with frequency continuously and smoothly. Therefore, they can be adjusted in a wide range to achieve isolation of low frequency vibration when using proper control parameters. A simulation example shows that the transmission force with a CPC is lower in the 8–50Hz when the rotor displacement is almost same as with a single stage PID controller (SSPC). Experimental verification was carried out in an experimental bench of AMB under unbalanced rotor condition. Results show that a CPC can reduce the vibration acceleration at 15–50Hz especially near the peaks. Simulation and experimental results well demonstrate the effectiveness and guaranteed stability of the CPC in the present study.

Optimal fuzzy PID controller design for an active magnetic bearing system based on adaptive genetic algorithms

2014 ◽  
Vol 24 (5) ◽  
Author(s):  
HUNG-CHENG CHEN
Keyword(s):  
Genetic Algorithm ◽  
Pid Controller ◽  
Controller Design ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Adaptive Genetic Algorithm ◽  
Fuzzy Pid ◽  
Fuzzy Pid Controller ◽  
Pid Controller Design ◽  
Amb System

We propose an adaptive genetic algorithm (AGA) for the multi-objective optimisation design of a fuzzy PID controller and apply it to the control of an active magnetic bearing (AMB) system. Unlike PID controllers with fixed gains, a fuzzy PID controller is expressed in terms of fuzzy rules whose consequences employ analytical PID expressions. The PID gains are adaptive and the fuzzy PID controller has more flexibility and capability than conventional ones. Moreover, it can be easily used to develop a precise and fast control algorithm in an optimal design. An adaptive genetic algorithm is proposed to design the fuzzy PID controller. The centres of the triangular membership functions and the PID gains for all fuzzy control rules are selected as parameters to be determined. We also present a dynamic model of an AMB system for axial motion. The simulation results of this AMB system show that a fuzzy PID controller designed using the proposed AGA has good performance.

scholarly journals Radial Planar Magnetic Bearing Analysis With Finite Elements Including Rotor Motion and Power Losses

1997 ◽  
Author(s):  
R. D. Rockwell ◽  
P. E. Allaire ◽  
M. E. F. Kasarda
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Electric Fields ◽  
Eddy Current ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Magnetic Vector Potential ◽  
Power Losses

No literature is currently available which has evaluated finite element power loss models for magnetic bearings and compared the results to experimental results. In this paper a finite element model of the magnetic and electric fields in magnetic bearings, including the motion of the magnetic material in the rotor, is developed. It evaluates the two dimensional magnetic vector potential, magnetic flux density, electric field, eddy current, and power losses in an example magnetic bearing configuration. Results were obtained for both a solid rotor and a laminated rotor. For a solid rotor, both the magnetic flux density and eddy current plots at high rotational speeds are concentrated at the outer edge of the rotor. The ratio of calculated solid to laminated losses is found to be in the range of measured results by other authors. An effective axial conductivity was employed to model a laminated rotor and compared to experimental loss measurements. The correlation between measured and calculated results is quite good for a range of rotor speeds, magnetic flux density, and air gap thickness.

Magnetic Bearing Rotordynamic System Optimization Using Multi-Objective Genetic Algorithms

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Wan Zhong ◽  
Alan Palazzolo
Keyword(s):  
Genetic Algorithms ◽  
Magnetic Flux ◽  
System Optimization ◽  
Magnetic Bearing ◽  
Multiple Objective ◽  
Control Law ◽  
Power Losses ◽  
Geometrical Features ◽  
Spinning Shaft ◽  
Pareto Frontiers

Multiple objective genetic algorithms (MOGAs) simultaneously optimize a control law and geometrical features of a set of homopolar magnetic bearings (HOMB) supporting a generic flexible, spinning shaft. The minimization objectives include shaft dynamic response (vibration), actuator mass and total actuator power losses. Levitation of the spinning rotor and dynamic stability are constraint conditions for the control law search. Nonlinearities include magnetic flux saturation, and current and voltage limits. Pareto frontiers were applied to identify the best-compromised solution. Mass and vibration reductions improve with a two control law approach.

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