Active magnetic bearings (AMBs) are a mature bearing technology that is being applied to many new turbomachines. They have become the bearing of choice for most new turboexpander applications. They are seen as a key enabling technology for compact, high speed, high power density direct-drive generators and turbomachinery. As more and more units are fielded, it will become important that end-use...

This paper deals with the experimental control of a rotating active magnetic bearing (AMB) system using PID-type fuzzy controllers (PIDFCs) with parameter adaptive methods. There are three kinds of parameter adaptive methods, including fuzzy tuner, function tuner, and relative rate observer, have been proposed in literatures for tuning the coefficients of PIDFCs. However, only a simulation comp...

This study is concerned with a three-pole active magnetic bearing (AMB) system assembly error and non-uniform flux distribution. The error, which the result of misalignment back-up stator AMB, induces strong nonlinear uncertainty in AMB dynamics. distribution, mainly due to material properties, manufacturing errors, etc., makes force model more complicated. A stable-levitation controller design...

In the rotating electrical machines, active magnetic bearing are basically performing the same role like mechanical bearings to support rotor. The function is based on the principle of magnetic levitation. The idea behind this involves creation of a magnetic field by supplying controlled currents in the bearing coil through amplifiers and complex power electronics. The accurate design of a magn...

Zero-bias or low-bias control of AMB's is essential for the design of magnetic bearings with low power losses. This paper investigates the use of control Lyapunov functions (clf's) to solve the problem of global asymptotic stabilization for a zero-bias Active Magnetic Bearing (AMB). We use the cascade structure of the system to derive a clf for the AMB model which is then used to derive a stabi...

Active magnetic bearing (AMB) systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and ax...

In this paper we present several nonlinear control designs for a single one-degree-of-freedom (1-DOF) Active Magnetic Bearing (AMB). The primary control objective is to globally asymptotically stabilize the mechanical states of an AMB while reducing the AMB power losses. This suggests operation with zero or low bias flux. We derive a flux-based model for an AMB using a generalized complementary...

This paper proposes a novel adaptive genetic algorithm (AGA) for the multi-objective optimization design of a fractional PID controller and applies it to the control of an active magnetic bearing (AMB) system. Different from PID controllers with three constants, the fractional PID controller’s parameters are composed of proportional constant, integral constant, derivative constant, derivative o...

Crack fault of rotor is one of the most prominent problems faced by magnetic bearing rotor system. In order to improve the safety performance of this kind of machinery, it is necessary to research the vibration characteristics of magnetic bearing cracked rotor system. In this paper, the stiffness model of the crack shaft element was established by the strain energy release rate (SERR) theory. T...

The upscale CNC machine is the research object, the magnetic levitation bearing technology which is suitable to AMB spindle and guide are researched. On the basis of the structure and working principle of AMB and the stiffness and damping characteristics, the performance of electromechanical coupling dynamics is studied according to the theory of traditional dynamics and the characteristics of ...