Research on composite hierarchical anti-disturbance strategy for magnetic bearing rotor using H∞ and observer

The magnetic bearing rotor system is affected by internal uncertainties and various forms of external disturbances, which will affect the stability of the active magnetic bearing system. To address this issue, a composite hierarchical anti-disturbance strategy is used to improve the anti-disturbance ability of the magnetic bearing rotor system. The disturbance observer is used to compensate the system’s external disturbances, and the controller is used to suppress the system’s internal uncertainties. For this purpose, H∞ controller, disturbance observer (DOB), and linear extended state observer (LESO) are designed, respectively. Then, H∞ controller is combined with DOB and LESO to form H∞-DOB and H∞-LESO composite controllers and prove their stability. Finally, simulation and experiments show that H ∞-DOB and H ∞-LESO have better disturbance suppression effects than the H ∞ controller for external disturbances. And when the disturbance frequency or rotor rotation frequency of the system is high, H ∞-LESO controller has better disturbance suppression effect than H ∞-DOB.