Research On Active Magnetic Damper For Vibration Control

Magnetic damper is a kind of actuator for vibration control using electro-magnetic force, whichhas been widely researched and used due to its advantages such as no friction, doesn’t need lubricationand long service life.Passive magnetic damper designed for rotor vibration control is optimized. The optimization isbased on the algorithm of sequential quadratic programming method, using optimal toolbox inMATLAB. The optimization yields the passive magnetic damper’s maximum damping coefficient andcorresponding structure and electric parameters. The unbalance response amplitude of magneticbearing-rotor system under the different damping coefficients before and after optimization isanalyzed using finite element method. When the rotor passes the translational and first critical speed,the vibration amplitude at both supporting ends and the place where passive magnetic damper isinstalled is decreased, and steady operation of the rotor system is ensured.Influence of analog PID controller’s parameters on the equivalent stiffness and damping of activemagnetic damper for rotor vibration control and SDOF vibration control, respectively, is discussed.The result shows that the proportional and differential blocks’ tunable resistance values have a muchgreater influence on the equivalent stiffness and damping than that of the integral block.Hammering test is conducted on active magnetic damper for SDOF vibration control. Thedamper system’s static frequency response function is obtained and the damper’s stiffness anddamping are calculated, and the stiffness acquired from experiment is compared with its theoreticalvalue. Excitation test is conducted under the condition of different PID controller’s parameters andvibration frequencies. The output voltage signal of displacement sensor is recorded. And thecorresponding theoretical value of stiffness, damping and the displacement of thrust disc in thedamper are calculated, respectively. The experimental value of thrust disc’s displacement is basicallytallies with the theoretical value. The experiment proves the theoretic analysis.