Research On The Performance And Application Of Rotating Hybrid Excitation Eddy Current Damper

The eddy current damper is an energy dissipation and vibration reduction device made by the eddy current principle.It has the advantages of simple maintenance,no need of sealing,adjustable damping,etc.It has broad application prospects in the field of vibration control.In this paper,through theoretical derivation,experimental research and finite element simulation methods,the damping performance of the rotating hybrid excitation eddy current damper is studied in depth,and the influence of the relevant structural parameters of the eddy current damper on its damping characteristics is summarized.The main research content and the results are as follows:1.Based on Biot-Savart law,the expressions of the magnetic induction intensity components at any point in the outer space of the cylindrical permanent magnet and the cylindrical solenoid are derived respectively.The results show that the magnetic induction intensity of the permanent magnet is proportional to the residual magnetization and is proportional to The radius and height are related;the magnetic induction intensity of the electromagnet is proportional to the total number of turns and current,and is related to the inner diameter,outer diameter and height;the magnetic induction intensity of the permanent magnet and the electromagnet decreases with the increase of the surface distance.When the distance is not more than 7mm,the magnetic induction intensity attenuation rate is not more than 25%.2.The expression of the eddy current damping coefficient of a single magnetic field source is derived based on Faraday’s law of electromagnetic induction.The results show that the eddy current damping coefficient is proportional to the thickness of the conductor disc and the square of the magnetic induction intensity,and to the resistivity of the conductor disc and the ball screw The square of the lead is inversely proportional,and is related to the radius r₁of the magnetic field source and the distance r₂ from the center of the magnetic field source to the center of the conductor plate.When r₁/r₂≈2/3,the eddy current damping coefficient reaches its peak value.3.The performance test was carried out on the prototype of the rotating hybrid excitation eddy current damper.The results show that the eddy current damping force and the loading speed amplitude basically conform to a linear relationship at low speed;the eddy current damping force and the loading current basically conform to a quadratic relationship,and the damping force generated by the electromagnet part accounts for 40%of the total eddy current damping force.4.The parametric analysis of the finite element model of the rotating hybrid excitation eddy current damper was carried out,and the related structural parameters such as back iron,conductor disc,magnetic field source,air gap,loading current,relative motion speed,etc.were investigated.The results show that the eddy current damping force has a non-linear relationship with the change of relative motion speed.Therefore,the design of the damper should fully consider the requirements of the working speed of the damper,and the critical speed of the damper and the maximum eddy current damping force should be optimally designed.5.A tracking control algorithm based on linear quadratic classic optimal control is designed.A semi-active control structure is compared with an uncontrolled structure and a passive control structure through an example.The performance of the eddy current damper has a good damping effect in structural vibration control,which further proves that the rotary hybrid excitation electric eddy current damper is a semi-active control device with good performance.