Backstepping Control of Three-Pole Radial Hybrid Magnetic Bearing

To improve dynamic performance and robustness of a three-pole radial hybrid magnetic bearing (HMB), a backstepping controller is designed in this study. After introducing configuration of the three-pole radial HMB, the mathematical model is established by using the equivalent magnetic circuit method, and then the state equations are derived. Based on the state equations, the backstepping controller is designed by conducting backstepping algorithm and Lyapunov theorem which is adopted to confirm the stability of the system. Aiming at the difficulty of parameter adjustment, the adjustment factor is introduced through theoretical analysis. And the suitable value range of regulation factor is given by simulation. To identify the validity of the presented controller, the backstepping controller and the proportional–integral–derivative (PID) controller are compared by simulation and experiment. Simulation and experimental results have verified that the dynamic performance and the robustness of the backstepping controller are superior to the PID controller.