Fractional-Order Super-Twisting Sliding Mode Control for High-Speed Permanent Magnet Synchronous Generators Based on a Disturbance Observer

The application of new high-power generation systems imposes strong requirements on the control system of high-speed permanent magnet synchronous generators (PMSGs) for robust disturbance rejection. To enhance the disturbance suppression capability of the generation system under complex operating conditions, this paper proposes a fractional-order super-twisting sliding mode voltage control strategy based on a disturbance observer. First, the load current is considered as a system disturbance, and a disturbance observer based on an improved super-twisting algorithm is designed. Then, the fractional-order and super-twisting sliding mode control algorithms are combined to design a fast-converging fractional-order super-twisting sliding mode voltage controller, with the disturbance estimate fed forward to the voltage controller to improve the disturbance rejection capability. The stability of the disturbance observer and voltage controller are proven using Lyapunov theory. Finally, experimental validation is carried out on a high-speed PMSG test platform. The experimental results demonstrate that the proposed control strategy offers better robustness and dynamic performance.