Cross-Feedback Stabilization of the Digitally Controlled Magnetic Bearing

1992 ◽  
Vol 114 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Y. Okada ◽  
B. Nagai ◽  
T. Shimane
Keyword(s):  
Pid Control ◽  
High Speed ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Magnetic Bearing ◽  
Feedback Stabilization ◽  
Time Interval ◽  
Rotating Disc ◽  
Digitally Controlled ◽  
The Cross

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.

Investigation of cross-coupling effect and its restraining methods of a 3-DOF hybrid magnetic bearing

2018 ◽  
Vol 37 (6) ◽  
pp. 2195-2210 ◽  
Author(s):  
Yunlong Zhong ◽  
Lijian Wu ◽  
Youtong Fang ◽  
Xiaoyan Huang
Keyword(s):  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Magnetic Bearing ◽  
Axial Thrust ◽  
Content Type ◽  
The Cross ◽  
Saturation Effects ◽  
And Control ◽  
Force Characteristics

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.

Closed Loop Performance of a Slotless Lorentz Self-Bearing Motor

2003 ◽  
Author(s):  
Hooi-Mei Chin ◽  
L. Scott Stephens
Keyword(s):  
High Speed ◽  
Closed Loop ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Motor Design ◽  
High Speed Rotation ◽  
Bearing Stiffness ◽  
Speed Rotation ◽  
Power Densities ◽  
Tangential Directions

In previous work the authors presented a Lorentz self-bearing motor design targeted for precision pointing and smooth angular slewing applications. The motor also offers potential advantages when operated as a synchronous machine at high speed including larger power densities and shorter shafts. In this paper, the closed loop performance of the motor at low transient speeds (0–588 rpm) is presented. Using these results, several challenges to achieving high-speed rotation are identified and discussed. The most significant is the heavy cross coupling within the actuator which limits bearing stiffness and stability, and is amplified at rotor natural frequencies resulting in potential loss of levitation when passing through critical speeds. Of particular interest is the discovery of a significant cross coupling effect between the radial and tangential directions. A theory is put forth explaining this effect.

High-Precision Cutting Tool Tracking With a Magnetic Bearing Spindle

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Alexander Smirnov ◽  
Alexander H. Pesch ◽  
Olli Pyrhönen ◽  
Jerzy T. Sawicki
Keyword(s):  
Pid Control ◽  
Disturbance Rejection ◽  
High Speed ◽  
Cutting Tool ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
External Loading ◽  
Reference Tracking ◽  
Tool Position ◽  
Tool Tracking

A method is presented for tool tracking in active magnetic bearing (AMB) spindle applications. The method uses control of the AMB air gap to achieve the desired tool position. The reference tracking problem is transformed from the tool coordinates into the AMB control axes by bearing deflection optimization. Therefore, tool tracking can be achieved by an off-the-shelf AMB controller. The method is demonstrated on a high-speed AMB boring spindle with a proportional integral derivative (PID) control. The hypothetical part geometries are traced in the range of 30 μm. Static external loading is applied to the tool to confirm disturbance rejection. Finally, a numerical simulation is performed to verify the ability to control the tool during high-speed machining.

Theoretical Investigation on Cross-Coupling Effect of Two-Dimensional Compound Pendulum Tiltmeter

2018 ◽  
Vol 07 (02n03) ◽  
pp. 1850007
Author(s):  
Lihua Wu ◽  
Yu Huang
Keyword(s):  
Dynamic Response ◽  
Vibration Isolation ◽  
Coupling Effect ◽  
Low Frequency ◽  
Cross Coupling ◽  
Coupling Factor ◽  
Two Dimensional ◽  
Coupling Coefficients ◽  
Coupling Effects ◽  
The Cross

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.

scholarly journals The Stability of Magnetic Levitation Milling System Based on Modal Decoupling Control

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xiaoli Qiao ◽  
Xiaoping Tang
Keyword(s):  
High Speed ◽  
Stability Region ◽  
Magnetic Levitation ◽  
Coupling Effect ◽  
Magnetic Bearing ◽  
Decoupling Control ◽  
Active Magnetic Bearing ◽  
High Speed Milling ◽  
Milling Stability ◽  
The Stability

Milling stability not only reduces the surface quality of the workpiece but also seriously restricts the high-speed development of CNC machine tools. The electric spindle rotor system with the active magnetic bearing has a strong gyro coupling effect, and with the increasing rotor speed, it will become a major unfavorable factor for the stability of the system during high-speed milling. The strong gyro coupling effect makes the stability region narrow at the time of high-speed milling. So, a modal decoupling control method that can reduce the effects of the gyro effect on the magnetic levitation milling system under high-speed milling is proposed. The effects of the gyro coupling of the magnetic bearing rotor on the milling stability region before and after the decoupling control are studied, which show that the modal decoupling control technology can reduce the effects of the gyro effect on the magnetic levitation milling system.

scholarly journals Time-Sharing Control Strategy for Multiple-Receiver Wireless Power Transfer Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 599 ◽  
Author(s):  
Weikun Cai ◽  
Dianguang Ma ◽  
Xiaoyang Lai ◽  
Khurram Hashmi ◽  
Houjun Tang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Output Voltage ◽  
High Efficiency ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Time Sharing ◽  
Voltage Control Strategy ◽  
Bridge Rectifier ◽  
The Cross ◽  
Target Output

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.

Alternative soft fault model of the cross-coupling effect correlated at hydroelectric power energy system

2014 ◽  
Vol 58 ◽  
pp. 274-280
Author(s):  
G. Mino-Aguilar ◽  
G.A. Muñoz-Hernández ◽  
J.F. Guerrero-Castellanos ◽  
E. Molina-Flores ◽  
A. Díaz-Sánchez ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Cross Coupling ◽  
Energy System ◽  
Fault Model ◽  
Hydroelectric Power ◽  
Soft Fault ◽  
The Cross
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