Design And Simulation Of A μ Controller Of AMB For A Vertical Flywheel Battery

Flywheel battery is revolutionary way of energy storage which have high energy densityand the advantage of Environment-friendly. Magnetic bearing is a non-contact Supportingtechnology, and an important component of flywheel battery. The result of rotor dynamicsanalysis and optimal design of the flywheel rotor is presented at firstly. And the primaryobjective of this paper is to design aμcontroller of active magnetic bearing (AMB).To ensure the smooth operation of high-speed flywheel rotor, rotor dynamics analysis isneed to get the critical speed and unbalance response of the rotor. The impact of differentradial bearing stiffness on the critical impact speed is discussed. Based on this, in order toreducing the rotor unbalance response, the rotor is optimal designed using gradient projectionmethod. The optimization goal is to make displacement of the key nodes of the rotor gettingthe minimum and the optimization variables is the shaft length of the flywheel rotor. Afteroptimization, the maximum displacement amplitude decreased by 40%, the average decreaseof 11%, reaching a good optimization resultsController is the core of active magnetic bearing design. Based on the theory ofμanalysis and synthesis, twoμcontrollers are designed for the axial magnetic bearing andradial magnetic bearing. In axis active magnetic bearing controller side, as the axis bearing isa hybrid magnetic bearing with an active magnetic bearing and a permanent magnet bearingusing for unloading, some error comes out when the permanent magnet force is linearized. Inorder to ensure stable suspension,the permanent Magnetic force displacement stiffness errorand the temperature drift of displacement sensor are taken as uncertainty to design the axisμcontroller. Simulation results show that the controller can achieve rotor suspension from thefloat and stability, and has some anti-interference ability. In radial controller side, through theanalysis of the radial four degrees of freedom model, the system is affected by the gyroscopiceffects, which means system parameters associated with the rotor speed. To solve thisproblem, a centralizedμcontroller of the radial 4-DOF of flywheel rotor is designed, whichtake the Parameter perturbation of gyroscopic effects the temperature drift of displacementsensor as the uncertainty. Simulation results show that the controller has a good responseperformance, and meets the job requirements.