A robust chattering-avoiding sliding mode control for Buck-Boost converter

In the process of power generation by new energy sources, such as wind, light and hydrogen, the randomness of energy input and power output often appear; this puts forward higher requirements for the robust design of power converters. The power converter based on traditional sliding mode, due to its discrete control law, makes chattering phenomenon inevitable. In order to suppress the above problem, this paper presents a novel chattering-avoiding converter based on the super-twisting sliding modes. The core idea is to transfer the discrete control law to high order sliding manifold, essentially eliminating the impact of chattering effect. To remove the intermittent disturbance in the new energy power generation, this paper compares the effect of the converter controlled by super-twisting sliding mode controller with the classic PI controller in a typical Buck-Boost power converter as an example. The simulation results and their analysis show preliminarily that: (1) under the condition of large disturbances in input and output, the converter controlled by super-twisting sliding mode has stronger robustness; (2) in response tracking, the converter has a faster convergence; the frequency response can reach more than 20 Hz, far superior to the classic PI control.