Analysis of the cross-coupling effect and magnetic force nonlinearity in the 6-pole radial hybrid magnetic bearing

2019 ◽  
Vol 61 (1) ◽  
pp. 43-57
Author(s):  
Dawid Wajnert
1992 ◽  
Vol 114 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Y. Okada ◽  
B. Nagai ◽  
T. Shimane

A method of stabilizing a high speed rotor supported by magnetic bearings is presented. The magnetic bearing is controlled by a digital controller with rotationally synchronized interruption. The main problem with the rotating disc is the cross-coupling effect caused by the gyroscopic or inductive forces which sometimes make the high speed rotor unstable. Standard PID control is carried out with constant time interval interruption, while the rotational interrupt subroutine performs the cross-coupling feedback. The cross-feedback in the x-y directions well compensates for the undesirable coupling effect. This scheme is applied to a four-mass, two-bearing rotor system and its capability is tested.


Author(s):  
Yunlong Zhong ◽  
Lijian Wu ◽  
Youtong Fang ◽  
Xiaoyan Huang

Purpose The purpose of this paper is to investigate and restrain the cross-coupling effect among X, Y and Z-axes of a three degrees of freedom hybrid magnetic bearing (3-DOF HMB). The influence of the cross-coupling effect on the force characteristics and stiffnesses are analysed. Two additional methods are proposed to eliminate the cross-coupling effect. Design/methodology/approach Analysis with finite element method (FEM) is time-consuming because of the requirement of a 3D model for the studied 3-DOF HMB. Hence, an improved magnetic circuit model considering the leakage, cross-coupling and saturation effects is used to investigate the cross-coupling effect in this paper. In addition, two restraining methods are proposed. One is adding an auxiliary coil between radial and axial stators. The other is adding an iron ring between the PM and radial or axial stator. Findings The X-axis (or Y-axis) force characteristics and stiffnesses are significantly influenced by the Z-axis current, while other axes force characteristics and stiffnesses do not show the cross-coupling effect. Moreover, this cross-coupling effect is inversely related to the distance between axial thrust disk and radial MB part. Besides, adding an auxiliary coil can effectively eliminate the cross-coupling effect in whole work range and adding an iron ring can reduce the cross-coupling effect. Originality/value The cross-coupling effect and its restraining methods of a 3-DOF HMB are investigated, which is beneficial to the design and control of such 3-DOF HMB.


2018 ◽  
Vol 07 (02n03) ◽  
pp. 1850007
Author(s):  
Lihua Wu ◽  
Yu Huang

The active vibration isolation of low-frequency tilt is important for precise scientific measurement. However, the cross-coupling effects in tilt sensitive probes introduce negative effects on the performance of active isolation devices. In this paper, we show the structure and basic principle of compound pendulum (CP)-type tiltmeter, and analyze the dynamic response of the CP to the two-dimensional tilt vibrations. Besides, we deduce theoretically the mathematical model of the capacitive sensing of the displacements of the CP. Finally, we evaluate numerically the cross-coupling effects of a tilt sensitive probe including the cross-couplings of dynamic response and the different capacitance variations in two orthogonal degrees of freedoms. The maximum of the mechanical dynamic coupling factor is less than −60[Formula: see text]dB. The total cross-coupling coefficients including the different capacitance variations of the probe are both less than [Formula: see text]. Therefore, the cross-coupling effects don’t have to be considered for this kind of two-dimensional tilt sensitive probe.


Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 599 ◽  
Author(s):  
Weikun Cai ◽  
Dianguang Ma ◽  
Xiaoyang Lai ◽  
Khurram Hashmi ◽  
Houjun Tang ◽  
...  

The cross-coupling effect between the induction coils of a multiple-receiver wireless power transfer (MRWPT) system severely weakens its overall performance. In this paper, a time-sharing control strategy for MRWPT systems is proposed to reduce the cross-coupling between receiver coils. An active-bridge rectifier is introduced to the receivers to replace the uncontrollable rectifier to achieve synchronization of the time-sharing control. The synchronization signal generated by an active-bridge rectifier can be directly used to realize the synchronization of time-sharing control and hence saved the traditional zero-crossing point detection circuits for time-sharing circuits. Moreover, the proposed time-sharing system has the advantages of both operating under a resistance-matching condition and providing target output voltage for each receiver. Furthermore, a voltage control strategy was developed to provide both high efficiency and a target output voltage for each receiver. Finally, the simulation and experimental results show that the time-sharing MRWPT system reduced the cross-coupling effect between the receiver coils, and the voltage control strategy provided both a high efficiency and a target output voltage for each receiver.


Author(s):  
G. Mino-Aguilar ◽  
G.A. Muñoz-Hernández ◽  
J.F. Guerrero-Castellanos ◽  
E. Molina-Flores ◽  
A. Díaz-Sánchez ◽  
...  

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