Fractional-Order Adaptive Sliding Mode Control for Fractional-Order Buck-Boost Converters

In previous studies, the combination of fractional calculus (FC) and sliding-mode control (SMC) has been gaining more and more interest due to fusion characteristics of SMC and FC. But most study integer-order buck converters, and few study control strategies of fractional-order converters. In this paper, the sliding mode controller and fractional adaptive sliding mode controller for fractional-order buck-boost converters are proposed. An affine nonlinear system model of the fractional-order buck-boost converter is built. Based on the differential geometry theory, the exact feedback linearization is performed on the affine nonlinear model of the fractional-order buck-boost converter. On this basis, a fractional adaptive sliding mode controller is designed by selecting a linear sliding surface and adaptive control law. The stability of the fractional controller is proved by the Mittag-Leffler stability theorem. The simulation results show that the fractional adaptive sliding mode control has good dynamic response performance and small steady-stage error regulating characteristics. Compared with traditional sliding mode control and PI lambda control, the control method demonstrates stronger robustness under various disturbances.

Automated summary

This paper proposes a sliding mode control method for fractional-order buck-boost converters and designs a fractional adaptive sliding mode controller. Through feedback linearization and adaptive control law, this control method can achieve good dynamic response performance and steady-state error regulating characteristics.