Research On Control Strategy Of Electromagnetic Vibration Suppressor And Its Application In Cracked Rotor System

Electromagnetic vibration suppressor is a kind of equipment used to suppress the unbalanced vibration in the rotor system.It is developed on the basis of active electromagnetic bearing and adopts detachable structure.It can be installed without disassembly of other mechanical equipment,and exert control over the rotor by electromagnetic force under the condition of no mechanical contact and lubrication.It can greatly improve the operating condition of the rotor,and even suppress the vibration of the faulty rotor to the level before the fault occurs,and make the rotor system continue to serve with injury for a period of time under certain conditions.In this paper,the electromagnetic vibration suppressor is taken as the research object.The research on noise reduction of electromagnetic vibration suppressor based on kalman filter algorithm,the simulation and experimental research on the application of electromagnetic vibration suppressor in breathing cracked rotor system.The main research contents are as follows:(1)The principle and iterative process of kalman filter algorithm are introduced,and the algorithm is applied to the electromagnetic vibration suppressor system to eliminate the process noise and measurement noise in the working process of the electromagnetic vibration suppressor system.The finite element model of the rotor system is established and the electromagnetic force which has passed through kalman filter is added to the dynamic equation of the rotor system.Taking account of noise in the system,the vibration displacement response of the rotor system output and the current response in the coil of the electromagnetic vibration suppressor before and after kalman filter are compared and analyzed combined with domain diagram,axis track,spectrum diagram and Poincaré diagram.The results show that the kalman filter algorithm can effectively eliminate the interference of noise on the running process of electromagnetic vibration suppressor and improve the anti-noise ability of electromagnetic vibration suppressor.Next,the filtering effect under different noise intensity,different rotate speed and different controller parameters is analyzed,the results show that kalman filter algorithm can maintain good performance under different conditions.(2)The electromagnetic vibration suppressor is applied to the vibration suppression of breathing cracked rotor system.The additional flexibility coefficient matrix of shaft segment with transverse crack is obtained by theoretical derivation.The finite element model of the breathing cracked rotor system is established using cosine breathing model.The vibration response of the breathing cracked rotor system is compared and analyzed combined with domain diagram,axis track,spectrum diagram and Poincare diagram,the results show that the electromagnetic vibration suppressor can greatly improve operating condition of cracked rotor system.The influence of the controller parameters to vibration suppression effect is researched combined with bifurcation diagram and waterfall diagram,etc.A great influence is found that equivalent proportional coefficient to vibration suppression effect.With the increase of equivalent proportional coefficient,vibration displacement amplitude decreases,but too large an equivalent proportional coefficient will result in instability of the system easily;Equivalent differential coefficient affects the displacement overshoot mainly,the appropriate increase of equivalent differential coefficient can reduce the displacement overshoot;Vibration suppression effect is also influenced by bias current.With the increase of bias current,vibration displacement amplitude and the impact degree of crack to the rotor system both show a trend of decreasing first and then increasing.(3)Through careful study of the mechanical structure of electromagnetic vibration suppressor,the performance and technical index of electronic devices and data acquisition equipment,the design and construction of the experimental platform of electromagnetic vibration suppressor-breathing cracked rotor system are completed.Relevant experimental is carried out,and the time domain and frequency spectrum of the vibration response are obtained by processing the data collected from the experiment.By comparing and analyzing the processed results with the simulation results,it is found that although there are some differences between the experimental results and the simulation results in specific values,they are consistent in the overall trend,which verifies the correctness of the theoretical simulation and provides some practical basis for the vibration control of the cracked rotor.