Second-Order Sliding-Mode Controller for Boost Converters With Load Estimation and Compensation

In this article, a second-order sliding-mode (SOSM) control theory is applied to the dc-dc boost converter. The proposed SOSM controller which is constructed with state-machine structure can achieve an approximate time-optimal response of the output voltage in the presence of unknown load disturbances without output current sensing or an integral term in the control loop. Switching conditions of the state-machine are obtained through the analysis of the optimal trajectories in the state plane. Furthermore, a load estimation algorithm is presented to enhance the robustness, and an adaptive compensation method is proposed to improve dynamic performance. The proposed approach is verified by experimental results on a 4A, 12V dc-dc boost converter prototype.