Control of zero-bias magnetic bearings using control Lyapunov functions

Zero-bias or low-bias control of active magnetic bearings (AMBs) is essential for the design of magnetic bearings with low power losses. This paper investigates the use of control Lyapunov functions (CLFs) to solve the problem of global asymptotic stabilization for a zero-bias AMB. We use the cascade structure of the system to derive a CLF for the AMB model which is then used to derive a stabilizing control law. This control law is designed so that the closed-loop system is homogeneous of degree with respect to a certain dilation. Simulation results are provided to evaluate the proposed control design.