Research on Support Characteristics and Controller Design of Magnetic Bearings Considering Eddy Current Effects

In order to meet requirements of high-speed and stable operation of magnetic bearing system, it is necessary to study change of support characteristics of magnetic bearing under action of eddy current effect in full speed range, and provide basis for design of magnetic bearing system controller. Considering eddy current effect, based on magnetic circuit method, formulas of electromagnetic force of magnetic bearings with different magnetic pole arrangements (NSSN, NSNS) are studied, and formulas of current stiffness coefficient and displacement stiffness coefficient of NSSN magnetic bearings are derived. Considering dynamic stiffness of magnetic bearing, according to stability evaluation method in Routh Criterion and ISO-14389, PID control parameter range of magnetic bearing system is determined. Control simulation model of magnetic bearing system based on dynamic stiffness is established, and adjusted parameters are imported into the model for simulation, simulation results show that control effect is satisfactory. This paper provides theoretical guidance for support characteristics of magnetic bearing and controller design of magnetic bearing system.