Fixed-Time Sliding Mode Control of DC-DC Buck Converter with Guaranteed Transient Performance

The stability and transient performance of DC-DC buck converter output voltage is critical. In order to address the voltage control problem under mismatched disturbances and time-varying output constraints, this paper proposes a voltage control framework of the DC-DC buck converter with the guaranteed prescribed performance and fixed stabilization time based on a higher-order fully actuated approach. Firstly, to estimate the mismatched disturbance, a fixed-time extended state observer (ESO) is designed. The original model of buck converter is transformed into a high-order fully actuated system. The uncertainties are approximated by a radial basis function neural network (RBFNN). Then, an adaptive fixed-time sliding mode control law is proposed. The proposed control law could guarantee the prescribed transient performance for the buck converter in the presence of load changing and bounded model uncertainties. The fixed-time stability of the closed-loop system is guaranteed by the Lyapunov approach. The proposed control law is evaluated by comparative experimental tests. Experimental results illustrate the effectiveness and superiority of the proposed control strategy.