Torque Ripple Minimization of Reaction Flywheel Based on Linear Extended State Observer

In spacecraft attitude control, the torque ripple generated by the reaction flywheel can significantly degrade the output torque precision and affect the satellite’s attitude stability. This paper focuses on the study of the six times harmonic torque ripple issue caused by the permanent magnet of the reaction flywheel. A proportional-integral-resonant (PIR) composite controller based on a linear extended state observer (LESO) is proposed to improve the output torque precision by suppressing the six times harmonic torque ripple. Firstly, the torque ripple in the system is observed using the LESO and compensated for through feedforward control. Next, as the compensated current signal contains high-order harmonics at six times the rotational speed, a PIR controller is employed to enhance the tracking ability of the current loop for harmonic signals. Simulation results demonstrate that the proposed method effectively reduces the torque ripple and improves the precision of the output torque of the reaction flywheel.