Study On Thrust Magnetic Bearing And Rotor Dynamics

Power magnetic bearing is essentially different from traditional magnetic bearing. Power magnetic bearing can produce not only radial magnetic suspending force bearing rotor but also torque driving rotor, so it integrate electromotor and bearing.Thrust magnetic bearing of power magnetic bearing has been emphasized and work principle of thrust magnetic bearing has been summarized in this paper. We induce mathematic model of thrust magnetic bearing and found control model. This paper analyzes electromagnetic field, whirlpool waste and magnetic suspending force of different spindle of thrust magnetic bearing based on finite element method. Thrust magnetic bearing structure has been designed in this paper based on simplified magnetic route method.Movement equation of thrust magnetic bearing and rotor system has been induced and closed loop transfer function of thrust magnetic bearing control system has been educed in this paper. Control system has been simulated applying MATLAB software. Emulator result indicate that PID controller can achieve steady suspend of thrust magnetic bearing.Digital controller arithmetic has been analyzed and digital control system of thrust magnetic bearing has been found in this paper. Parameter self-adaptive fuzzy PID control arithmetic has been brought forward that applies in thrust magnetic bearing in this paper.Based on theory which finite element solves rotor inherent frequency, rotor model has been analyzed this paper. Apiece rank inherent frequency and critical speed have been educed in this paper. Distortion displacement of rotor at critical speed and minimum driving torque passing critical speed of undamped rotor have been analyzed in this paper,which is meaningful for power magnetic bearing passing critical speed.