Abstract In previous studies of linear rotary systems with active magnetic bearings, parametric excitation was introduced as an open-loop control strategy. The realized by a periodic, in-phase variation the bearing stiffness. At difference between two eigenfrequencies system, stabilizing effect, called anti-resonance, found numerically and validated in experiments. this work, preliminary result...

Due to manufacturing flaws or cyclic loading, cracks frequently appear in a rotating spindle system. These cracks markedly affect the dynamic characteristics in higher modes of the rotating machinery. For faster rotational speeds, especially for super-high-speed cutting, a spindle with magnetic bearings is necessary. However, most investigations into spindle system dynamic characteristics have ...

The stability of flywheels in an energy storage system supported by active magnetic bearings (AMBs) is studied in this paper. We designed and built two flywheel energy storage systems (FESS) that can store up to 5 kWh of usable energy at a maximum speed of 18,000 rpm. One is optimized to store as much energy as possible, resulting in a flywheel with a strong gyroscopic coupling. The other has a...

Magnetic bearings are often designed using magnetic circuit theory. When these bearings are built, however, effects not included in the usual circuit theory formulation have a significant influence on bearing performance. Two significant sources of error in the circuit theory approach are the neglect of leakage and fringing effects and the neglect of eddy current effects. This work formulates a...

Friction is mostly unwanted in rotating machines. In order to reduce its impact on the system, the integration of magnetic bearings is frequently regarded as a valid solution. In rotating systems like flywheel energy storage systems (FESS), mechanical losses created by mechanical bearings greatly reduce the overall performance. Magnetic bearings are thus frequently integrated in FESS to elimina...

This paper deals with an application of H∞ control attenuating initial-state uncertainties to the magnetic bearing and examines the H∞ control problem, which treats a mixed Disturbance and an Initial state uncertainty Attenuation (DIA) control. The mixed H∞ DIA problem supplies H∞ controls with good transients and assures H∞ controls of robustness against initial-state uncertainty. On the other...

By using staggering magnets, we obtain a particular type of magneting bearings, owning very interesting properties : plane gap, null axial force, and absence of coupling produced by magnetization non-homogeneities. These bearings are well adapted for low rotational speed systems, and for partially-magnetic suspensions.