Lorentz force-type integrated motor-bearing system in dual rotor disk configuration

An integrated motor-bearing system combines the functions of an active magnetic bearing and an electric motor into a single unit. This paper proposes a generalized principle for the generation of torque and radial force in integrated motor-bearing systems using Lorentz force. The derived constraints lead to various feasible combinations of design parameters. Dual rotor disk configuration with a coreless stator is also proposed. It induces no negative stiffness, which is useful for the system stability and robustness to the tilting motion of the rotor. The test rigs are developed for five and six windings with an eight-pole rotor and operated successfully employing a simple PD-like controller.