Smooth Voltage Controller and Observer for a Three-pole Active Magnetic Bearing System

In this study, a simple and smooth voltage controller for a 3-pole active magnetic bearing (AMB) system is proposed. Based on the voltage-controlled AMB system, an observer is designed for the rotor displacement estimation. The observer will be based on the input voltages and coil currents that drive the magnetic poles. Such an observer can be utilized in the sensorless control of the AMB system. Due to the strong nonlinearity in the dynamics of 3-pole AMB system, the theory of nonlinear high-gain observer is adopted to design the observer. The proposed smooth voltage controller and nonlinear observer are verified numerically and experimentally.