Research On Hybrid Maglev Guiding System

Hybrid magnetic levitation guidance system is a hybrid excitation guidance system which uses permanent magnetic circuit to replace part of electromagnetic magnetic circuit.Compared with the guidance system of pure electromagnetic magnetic circuit,it has the advantages of small space occupied and cost saving.In order to overcome the shortcomings of the existing electromagnetic guidance system,a new hybrid magnetic levitation guidance system is proposed,and its basic principle and basic characteristics are analyzed and studied.Finally,the control research is carried out.The main contents of this paper are as follows.1.Aiming at the shortcomings of common linear elevator guidance system,a new structure hybrid excitation non-contact and low power guidance system is proposed.The structure and working principle of the new hybrid magnetic levitation guidance system are analyzed.2.The functional relationships among horizontal force and vertical force are deduced by using the theory of equivalent magnetic circuit.We get the relations between the displacement,controlled current and magnetic force by linearized processing.The simulation and calculation of magnetic force are compared and analyzed.The design result is carried out by using the finite element methods.The relationship between the length of PM,electromagnetic potential,the horizontal displacement and the horizontal force is discussed.The simulation results show that the hybrid excitation guiding system is reasonable and correct.3.Based on the magnetic flux and the control magnetic flux required by the maximum horizontal magnetic force,the electromagnetic parameters and the structural parameters are designed with reference to the mathematical expression of the horizontal magnetic force.The relationship between the structural parameters is analyzed.A two-dimensional finite element analysis model is established to verify the correctness of the analytical expressions of electromagnetic force and the rationality of parameter design.4.The mathematical expression of horizontal suspension stiffness is deduced.The effects of permanent magnet coercivity,permanent magnet cross-sectional area,permanent magnet thickness and electromagnetic force on the suspension stiffness are analyzed.The influence of air gap cross-sectional area and permanent magnet cross-sectional area ratio on the suspension stiffness is discussed by using the finite element method,and the law of electromagnetic flux and suspension stiffness is verified.The optimal suspension stiffness values at the optimal line are obtained,which proves that the horizontal magnetic force maintains a good linearity over a wide range.The choice of suitable structural parameters and high coercivity of the permanent magnet material can improve the suspension stiffness of the system,increase stability,save material,reduce costs and take up space.Finally,the influence of current and displacement on displacement stiffness and current stiffness is discussed.5.The state feedback controller and PID controller are designed for open-loop instability of the hybrid magnetic levitation guidance system.(1)The state feedback control is used to obtain the analytical expression of magnetic force by the equivalent magnetic circuit method.The equations of motion of the hybrid excitation guidance system are deduced according to Newton's second law and winding circuit equation.A linearized voltage control model with air gap,velocity and current as state variables was established,and a state feedback controller was designed and simulated.(2)The transfer function of the closed-loop control system is deduced by the classical PID control,and the relationship between the stability condition and the control parameters is given,and the simulation analysis is carried out by using the simulation software.The simulation results show that the system structure,the theoretical analysis and calculation are feasible,the design of the controller can achieve the stability of the hybrid excitation guidance system.The research results provide theoretical and design reference for the industrial application of this kind of hybrid excitation guidance system.