Comparative study of power minimizing control algorithms for active magnetic bearings

2012 ◽  
Author(s):  
Seong-yeol Yoo ◽  
Hak-in Lee ◽  
Myounggyu D. Noh
Keyword(s):  
Comparative Study ◽  
Magnetic Bearings ◽  
Control Algorithms ◽  
Active Magnetic Bearings

scholarly journals An Appraisal of Power-Minimizing Control Algorithms for Active Magnetic Bearings

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Seong-yeol Yoo ◽  
Myounggyu D. Noh
Keyword(s):  
Power Consumption ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Control Algorithms ◽  
Active Magnetic Bearings ◽  
Consistent Model ◽  
Complex Power ◽  
Derivative Type ◽  
Variable Bias

Active magnetic bearings consume much less power than conventional passive bearings, especially when power-minimizing controllers are employed. Several power-minimizing controllers have been proposed, such as variable bias controllers and switching controllers. In this paper, we present an appraisal of the power-minimizing control algorithms for active magnetic bearings in an attempt to provide an objective guideline on the merits of the control algorithms. In order for the appraisal, we develop an unified and consistent model of active magnetic bearing systems. The performances of the power-minimizing controllers are assessed through this model. The results show that the power-minimizing controllers indeed save considerable power when the machine state is relatively steady. However, a simple proportional-derivative type controller is on a par with the much more complex power-minimizing controllers in terms of power consumption when the machine is experiencing transient loads.

Vibration Control of a Turbo Molecular Pump Suspended by Active Magnetic Bearings

2011 ◽  
Author(s):  
Kai Zhang ◽  
Jinping Dong ◽  
Xingjian Dai ◽  
Xiaozhang Zhang
Keyword(s):  
Controller Design ◽  
Magnetic Bearings ◽  
Control Algorithms ◽  
Active Magnetic Bearings ◽  
Bending Mode ◽  
High Rotation Speed ◽  
Structure Vibration ◽  
The Stability ◽  
Bending Modes ◽  
Gyroscopic Effects

In a turbo molecular pump suspended by active magnetic bearings (AMBs), vibration caused by the rotor’s bending modes, gyroscopic effects and structure vibration modes influenced the pump performance and even cause instability. Different methods were used to deal with these problems. A Cross Feedback method was effective in restraining the nutation and precession of the rotor. A Phase Shaping method provided sufficient damping for the 1st bending mode of the rotor. The structure vibration instability was avoided by adjusting the joint strength between two parts of the pump housing. The gyroscopic effects also destroyed the stability of unbalance control algorithms for the AMBs at a high rotation speed. It was shown that, to ensure the stability of the controller when the unbalance control algorithms were applied, the 1st bending frequency of the rotor should be increased. Experiment results concerning the problems discussed above were provided. With a suitable controller design and an appropriate consideration of the dynamic problems, the rotor was successfully accelerated to 27 000 rpm.

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