Linear Observers Design for a Three-Pole Magnetic Bearing

In this work, linear observers for a three-pole active magnetic bearing (AMB) were designed and simulated, considering the AMB modelled as a linear dynamical system. Al- though the system being nonlinear, under the assumption of lower speeds, the linearized model can behave similarly to the nonlinear model. The linearized model was made from the reluctance forces equations and, as the system is naturally unstable, Linear Quadratic Regulator (LQR) was used to stabilize the system. The state vector contains both the horizontal and vertical sensor measurements, and also their derivatives, that are not mea- sured. For the state feedback with LQR, it is necessary to have all the state vector data, and linear observers are a way to obtain the non-measured states. Observation errors for the full and reduced order linear observers are then compared.