The Design Of Active Magnetic Bearing Control System Based On Fractional Order PID Controller

Fractional order PID control is a generalization of the conventional PID control.The algorithm of Fractional order PID control is simple and flexible,and the robust control effect is better than conventional PID control.In this paper,the algorithm was applied to the active magnetic bearing system to study and analysis the active magnetic bearing control system based on fractional order PID control.Firstly,according to the test bench,this paper analyzed and deduced the mathematical model of rotor-electromagnet,sensor and power amplifier and carried out rotor dynamics analysis under different support to obtain the critical speed of the rotor.The theory of fractional order calculus and its control theory were introduced,including the control principle and stability region analysis of fractional order PID.Secondly,the discretization method of fractional calculus operator s??is studied.The study shows that in the active magnetic bearing system,using Oustaloup to implement fractional order PID controller is accurate and practical.On this basis,this paper simulated and analyzed the effects of the parameters of fractional order PID controller on the system performance.Through comparing the step response and anti-jamming performance of the system using PID and fractional order PID controller,this paper demonstrated the robustness of the fractional order PID controller,and improved the parameter tuning method of conventional controller,using the genetic algorithm to optimize the parameters.Finally,the test platform of the active magnetic bearing system was built,and the software and hardware design of the control system were completed.Respectively from the static suspension and dynamic rotation test,the performance of the active magnetic bearing system with fractional order PID control was studied.The results show that the fractional order PID is more flexible than the conventional PID controller.When rotating with high speed under the first order bending natural frequency,the rotor radial amplitude decreased by 20% and the axial amplitude amplitude decreased by 48.9% compared to the conventional PID.