An Adaptive Nonsingular Terminal Sliding Mode Control for Bidirectional DC–DC Converter in Hybrid Energy Storage Systems

In order to improve transient response and robust tracking performance, an adaptive nonsingular terminal sliding mode control (ANTSMC) strategy is developed for bidirectional dc–dc converter (BDC) of hybrid energy storage systems (HESSs). By using the adaptive rules, the estimated values of load variations, external input voltage, input current, and output voltage can be obtained. Then, the voltage tracking error can be calculated based on the estimated value and the actual value. The fast terminal SMC strategy is proposed such that the tracking error converges in a finite time. Simulation results, compared with conventional PID, second-order sliding mode, show that output voltage can robustly track the reference voltage with fast response.