Optimization Control In The Process Of Magnetic Suspension Redundant Support Reconstruction

Magnetic-levitated bearings support the rotor by electromagnetic force,with the advantages of no lubrication,no mechanical friction,and controllable support characteristics,are widely used in high-performance equipment such as aero-engines,energy storage flywheels,nuclear turbine power generation equipment,etc..The basic control theory of magnetic-levitated bearings is based on the bias current linearization at the equilibrium position,namely,by the displacement-force coefficient and the current-force coefficient,electromagnetic force linearization is achieved.However,there is a symmetry constraint on the stator structure.while the faults in magnetic bearing systems,such as the faults of sensors and controllers in electronic control systems,electromagnetic actuators,etc.,will destroy the original symmetry of the support structure,leading to the failure of bearing system and serious impacts.In the case that the structure of the magnetic suspension support portion fails,the desired support characteristics are re-provided by the support reconstruction,which is a method for effectively improving the reliability of the magnetic suspension bearing.In this paper,the problems about optimization control in the process of magnetic suspension redundant support reconstruction were studied,including:(1)The first problem was the optimal selection of bias current coefficient.In this paper,the influence mechanism of bias current coefficient on the fault-tolerant control theory of magnetic suspension support-output biasing force in generalized bias current linearization was deduced,and the effective range of bias current coefficient was defined.The maximum output force under saturation constraint and the minimum controlled current under the same output force were used as the optimization targets.The optimal value’s selection method of the bias current coefficient was proposed,and the effectiveness of the method was verified by numerical calculation.(2)The second problem was the optimal solution of the current distribution matrix.Based on the generalized bias current linearization theory of non-equilibrium position,this paper proposed an optimal solution method for getting the optimal current distribution matrix,which was optimized to achieve the maximum expected electromagnetic force in any direction under saturation constraints.The nonlinear programming optimization model of equality constraint and inequality constraint was established,and the sequential quadratic programming algorithm was used to solve the problem.The correctness of the method was verified by numerical verification.(3)Lastly,a new control optimization target was proposed to improve the position control accuracy of the traditional PID control algorithm in the field of magnetic suspension bearing control,that was,the control object-rotor not only needs to move back to the equilibrium position,but its speed also needs to be zero when it returns to the equilibrium position;And based on the optimization goal,the concept of limit judgment value related to rotor speed and displacement was proposed,and an optimal control algorithm for active magnetic suspension bearing control system was designed.The simulation model was built in MATLAB/Simulink,which verified the dynamic performance and stability of the optimization control algorithm.The experimental research on the magnetic suspension rotor platform was carried out,and the effectiveness of the optimization control algorithm was verified.In this paper,some optimization problems in the process of support reconstruction were studied about the active magnetic suspension bearing system with the ability of support reconstruction.As a result,the performance of the active magnetic suspension bearing can be effectively improved.The research results can effectively supplement the existing optimization control theory of active magnetic suspension bearing.It has obvious innovation and has good theoretical and practical value.