Reducing magnetic bearing currents via gain scheduled adaptive control

A method for the reduction of an active magnetic bearing's speed-synchronous current is presented. The approach is based on research on adaptive vibration control for these systems. To minimize the memory and computational requirements imposed on the control system hardware, the gain matrix used is synthesized as functionally dependent upon the operating speed with only the diagonal elements varying linearly with speed. The resulting algorithm was experimentally tested on a high-speed spindle. Significant reductions in bearing currents were achieved over a wide range of operating speeds.