Design, modeling, and robust control of the flexible rotor to pass the first bending critical speed with active magnetic bearing

Abstract

Recently, magnetic bearings have been applied to many rotating machines such as turbo-molecular pumps, cooling gas compressor, flywheel energy storage systems. And high-power density is the future development trend of these machines, which demands that the rotor characterizes slender and high rotating speed and operates above the critical speeds. However, it is a big challenge for a flexible rotor to pass the bending critical speeds and operate above the critical speeds steadily and reliably. Based on above reasons, this article presented the design, modeling, and analysis framework of a flexible rotor test rig with active magnetic bearing (AMB). Special attention was paid to the flexible rotor dynamic model development, dynamic analysis, and model-based robust control design. First, the main structure features were illustrated in detail, including the key dimensions and parameters of the AMB components and rotor. Then models of components including power amplifier and displacement sensor were developed. The finite element method based on Timoshenko beam theory was applied to the rotor dynamics model. The dynamic analysis of the rotor is the foundation of the controller design. Hence, modal analysis had been done, obtaining rotor dynamic properties via synthesis of natural frequency, mode shapes, and Campbell plots. Reduced order model was obtained for controller design convenience. A robust H N controller was designed based on the system model and controller performance was validated with numerical simulation. The results indicate that the controller has good vibration suppression performance and makes the flexible rotor pass the first bending critical speed.

3D Model for Active Vibration Control of Rotating Machines Mounted on Active Machine Foot Mounts Using Vibration Mode Coupling by Asymmetry

“…critical speeds are lying in the operation speed range [1][2][3][4][5]. Implementing active vibration control [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] is an appropriate method to reduce vibrations, which is used in different technical applications. Here, the active vibration system consists of active machine foot mounts-actuators, which are positioned under the machine feet and only acting in vertical direction-and vibration sensors, which are mounted at each machine foot and detect the vertical vibrations leading this information to separate controllers ( Fig.…”

Analysis of Different Vibration Control Strategies for Soft Mounted Induction Motors with Sleeve Bearings Using Active Motor Foot Mounts

“…Therefore, the idea is to use active vibration control, which is a very powerful instrument, to optimize the vibration behaviour [6] [7] [8] [9]. For rotating machinery sometimes active magnetic bearings are used, especially for high speed applications, and have been optimized during time [10] [11] [12] [13] [14]. But also actuators-used as active mounts-have been investigated, to optimize the vibration behaviour of rotating machinery [15] [16] [17] [18] [19].…”

Novel repulsive magnetic bearing flywheel system with composite adaptive control

“…In most conventional systems, flywheels are supported by ball bearings. Unlike conventional mechanical bearings, magnetic bearings provide non-contact, frictionless, and oil-free mechanical motion between the rotating body and bearing with high precision [5][6][7][8][9]. This technology has mainly two types of bearing structures such as active magnetic bearings (AMBs) and passive magnetic bearings (PMBs).…”