Generalized super-twisting sliding mode controller for DC-DC buck converters based on a finite-time extended state observer

The control performance of active disturbance rejection controller for DC-DC buck converters under disturbances can be improved through structural enhancements to both the observer and controller components. Therefore, this paper proposes a finite-time extended state observer based generalized super-twisting sliding mode controller for DC-DC buck converters. Firstly, based on the novel dynamic model of DC-DC buck converters proposed in this paper, a finite-time extended state observer was established to estimate the system states and total disturbance within finite-time. The finite-time convergence of observer errors was proven through the construction of a Lyapunov function. Secondly, using the estimates provided by the observer, a generalized super-twisting sliding mode controller was designed, which suppresses the chattering by eliminating the discontinuous term under the integral of the super-twisting sliding mode controller. The stability of the proposed controller, considering the observer errors, was proven via Lyapunov stability theory. Finally, simulation and experimental results demonstrate its superior performance in controlling a DC-DC buck converter.