Abstract: In order to enhance the dynamic performance of the magnetically suspended reaction wheel (MSRW) in the braking process, improve its cross-zero speed characteristics and output moment precision, a nonlinear synergetic control approach for speed mode operation is presented. First, state-space average models of a flywheel system including the motor and the power converter are established. Then, a nonlinear synergetic control law for the system’s acceleration and braking operation is designed, and uncertain disturbing moment items are symbolized to improve the dynamic response of the disturbance torque restraint of the control system. Simulation and experimental results show that the approach can improve the cross-zero speed performance of flywheel systems, enhance the robustness of the flywheel against random disturbing moments, and improve braking control precision. The output moment precision of the flywheel reaches up to 6.2×10^-4N·m.

Key words: magnetic suspension, flywheels, speed control, synergetic, nonlinearity