Super Twisting Observer based Second Order Sliding Mode Control for Power Converter with Disturbance

Sliding mode control (SMC) has been widely used in DC-DC power converters due to its insensitivity the disturbances. In this paper, a super twisting observer-based second-order sliding mode controller is proposed for a buck converter with matched disturbance. First, the matched and mismatched disturbances due to load resistance and input voltage variations are transformed into a single matched total disturbance. Second, a super twisting observer (STO) is designed to estimate the states of a buck converter with matched disturbance in finite time. Then, the second-order sliding mode controller (SOSMC) is constructed utilizing a sliding surface with estimated states. The proposed controller and STO are tested using simulations with varying input voltage and load. The simulation results for the suggested technique show that reference tracking performance is effective in the presence of matched disturbances. The chattering is also decreased. The proposed controller enhances robustness to disturbances and uncertainty as well as dynamic performance.