Unbalance Force Observer and Compensator of magnetic bearings supporting centrifugal compressor

Magnetically suspended centrifugal compressors own unbalance forces in all degrees of freedom. The forces in radial directions are mainly derived from residual unbalance mass, and in axial directions are from shocking loads. These disturbances all can be observed using extended state observer, with which the unbalance forces can be compensated rapidly. In order to increase the precision of estimation and compensation, relevant parameters of magnetic bearings were theoretically and experimentally determined. The characteristics of the observer were studied through theoretical analysis and simulations. Additionally, a method, which can verify estimation accuracy was adopted in our research. At last, the unbalance force observation and compensation were realized on a suspended centrifugal compressor, which can be concluded that ESO owns fine disturbance rejection ability for active magnetic bearings.