Force analysis and measurement of permanent magnet biased AMB and PMB in hybrid magnetically suspended flywheel

For the hybrid magnetically suspended flywheel (MSFW), the magnetic forces generated by the permanent magnet (PM) biased AMB could make the flywheel rotor suspends at the radial equilibrium position, and the magnetic forces of the permanent magnetic bearing (PMB) could suspend the flywheel rotor at the axial equilibrium position. Firstly, the force model of the PM-biased AMB is developed, the weak coupling of magnetic forces among the x axis and y axis is quantitatively analyzed, and then the active suspension control of the flywheel rotor is realized by the PM-biased AMB. Furthermore, the force and torque models of the PMB are established, and the force characteristic of PMB with a negative stiffness could push the flywheel rotor back to the balanced status. Finally, the measurement experiments are conducted to verify the force characteristics of the PM-biased AMB and the PMB, the active control performance and weak coupling of the hybrid MSFW are verified by measuring displacement deflections.