The relevance of the topic is determined by the fact that nowadays scientific studies on a creation of new samples of magnetic bearings, as well as the methods of a mathematical description of dynamic processes, occurring in such the complex electromagnomechanical systems, in order to adequately select the parameters of magnetic bearings (MBs), which provide the necessary dynamic characteristics of the whole rotary machine are very actual, because the existing methods and approaches to modeling and analyzing the dynamics of rotors in MBs have a number of disadvantages associated.
The aim of the work is to solve the scientific and applied problem of creating a new general approach for a mathematical description of the dynamic behavior of rotors in systems with magnetic bearings of different types, which differs from the existing ones by a generalization of the approach and a completeness of taking into account a nonlinear interrelation of processes occurring in such the system – electric, magnetic and mechanical ones, that allows to achieve a possibility of adequate modeling and search for various dynamic phenomena and operational modes to find rational or optimal variants of designs of rotary machines with a reduced vibration and an increased reliability, as well as a verification of this method and its practical use.
The object of the study is dynamic processes in multidimensional interconnected mechatronic rotary systems, taking into account various factors that have a significant effect on their vibrational state and a movement stability of structural elements.
The subject of the study is linear and nonlinear phenomena of rotor dynamics in systems with magnetic bearings of different types, taking into account an interconnection of electrical, magnetic and mechanical stationary and non-stationary processes.
When solving the set tasks, analytical methods of the theoretical mechanics, the theory of oscillations, the mathematical analysis, the theory of automatic control, the theory of stability, the electrical engineering, the optimization theory, as well as the numerical methods and the methods of experimental research were used.
The theoretical significance of the work consists in solving an important scientific and applied problem of creating a conceptually new generalized method for a mathematical description of a dynamic behavior of rotors in systems and machines with passive and active magnetic bearings (PMBs and AMBs) in order to adequately reflect linear and nonlinear phenomena of the rotor dynamics and to evaluate a stability of a rotor movement in different modes.
The novelty of the scientific results is conditioned by a presence of a new generalized method for a mathematical description of a dynamic behavior of rotors in passive and active magnetic bearings, approaches to a determination of their parameters, results of calculation and experimental studies for a determination of the characteristics of the magnetic bearings themselves and rotor dynamics with their full consideration, a description of a new type of passive magnetic bearings with controlled stiffness and a based on it method of detuning from resonance modes in rotor systems with combined passive-active complete magnetic suspensions.
The practical value of the obtained results consists in that an application in the domestic industry of developed methods, techniques, algorithms and tools, among which: concept and method for constructing analytical models that describe the dynamics of rotors in passive and active MBs; the method for analysis of electromagnetic circuits of AMBs; the technique of finite-element calculation of power and stiffness characteristics of MBs; the computer and software tools for calculating the parameters of MBs and the rotor dynamics; a new type of PMB with a controlled stiffness and a way of passing resonance modes when accelerating and stopping rotors in a passive-active magnetic suspension, improves a credibility of calculating the parameters of the rotors, the magnetic bearings and control systems of AMBs, which enables to reduce costs and an energy consumption, increase reliability and competitiveness for enterprises. The results of scientific researches were introduced in practice of PJSC “Sumy NPO”, as well as a scientific activity and an educational process of the National technical university “Kharkiv Polytechnic Institute”.
