Losses in hybrid and active magnetic bearings applied to Long Term Flywheel Energy Storage

In this work, Radial Active Magnetic Bearings (RAMB) and PM-biased Hybrid Radial Magnetic Bearings (HRMB) were designed and optimized in the case of the Flywheel Long Term Energy Storage (LTFES). Taking into account the amplitude of external disturbance as well as unbalance force as load capacity, the effect of losses (non including losses in the power electronic) on the both RAMB and PM-biased HRMB was studied. Flywheel discharge times have been computed and drawn for a flywheel rotating at a nominal speed of 9000 rpm and self-discharging down to half-speed (4500 rpm). The evolution of this time duration versus mass of bearings is shown for different values of unbalance forces for these two magnetic bearing configurations.