Development and modeling of the three-element system of control of electromagnetic bearing

A three-loop control system of radial (and axial) electromagnetic bearing for powerful rotating machines, working air gap of which between the stator and rotor are tenths of millimeter if rotor weighs about one ton, is proposed. In the open state the system is unstable and has the features, which must be considered while synthesizing the regulators. Setting up the system is made by sequential optimization of control loops in accordance with the general principles of construction of the systems of the subordinate regulation. In accordance with the mathematical model of the electromagnetic bearing in the form of transfer functions and the corresponding block diagrams, the simulation models of the three-loop control system in the software package Matlab Simulink are constructed. Initially the inner loop with proportional-integral regulator was studied. The introduction of the internal circuit improved the system performance, but the simulation showed that the three-loop control system of the electromagnetic bearing has a static error. To make the system isoc, an integral controller is introduced into the outer contour of the situation. The transient analysis in the simulation showed that the electromagnetic bearings, equipped with the three-loop control system, have a high static rigidity and high speed. The failures of the rotor under the influence of external disturbing forces allow us to speak about the dependence of the dynamic stiffness of the electromagnetic bearing on the time constant of integration in the external position loop. An example of the use of research results can be a gas blower with 16 MW of the compressor station "Pomarskaya" of the pipeline "Urengoy–Pomary–Uzhgorod".