Second-order sliding-mode control of synchronous buck converter based on sub-optimal algorithm

The second-order sliding-mode controller based on improved sub-optimal algorithm for synchronous Buck converte r is designed, and the converter can be controlled only by detecti ng the output voltage without measuring the capacitance current of the converter. By introducing hysteresis to sub-optimal algorit hm, the switching frequency of the converter is limited when the output voltage is stable. In the Simulink, the first-order sliding-mode and second-order sliding-mode controller are actualized by using the state machine, the simulation test and verify the start-up performance and steady-state behavior and the robust against the large load disturbance jump from 10A to 20A and the power disturbance jump from 5V to 10V. The simulation results show that the proposed second-order sliding-mode controller retains the robustness of sliding mode control and is superiors to first order s liding-mode control in the aspect of resisting disturbance.