Super-Twisting Algorithm Based on Fast Terminal Sliding Surface for Buck Converter in Fuel Cell Electric Vehicle

As one of the most common step-down DC-DC switching power converters, Buck converters with the simple structure and easy control are widely applied to the fuel cell electric vehicles. In order to reduce chattering phenomenon which is inherent in conventional sliding mode control and solve the problem of slower convergence rate of the linear sliding surface, this paper presents a novel super-twisting algorithm based on the fast terminal sliding surface (STA+FTSS) strategy on basis of the super-twisting algorithm based on the linear sliding surface (STA+LSS) by adding the nonlinear term to LSS. Comparisons of numerical simulation results between the STA+LSS and the STA+FTSS are presented and discussed for various test conditions such as steady state, input voltage variations, output load disturbance and uncertainness in circuit parameter. It is worth to note that the proposed controller has a better performance related to the STA+LSS in terms of the transient response time and robustness to the disturbance.