Levitation Displacement Control of Bearingless Switched Reluctance Motor with UDE-Based Method

The radial levitation displacement control strategy for four-degree-of-freedom (4-DOF) bearingless switched reluctance motor (BSRM) conventionally depends on the accuracy of the analytical model. However, the analytical model of BSRM is difficult to precisely formulate. In this paper, a controller with uncertainty and disturbance estimation (UDE) capabilities is utilized to directly establish the displacement-current control loop. This method estimates the parameter perturbation and external interference changes of the system through filters and feedforward compensates them into the control loop, which reduce the dependence on the accurate analytical model. Simulation results show that the proposed method improves the steady-state accuracy of levitation displacement and has good suppression ability for step and periodic disturbances.