Super Twisting Sliding Mode Control of Dual Active Bridge DC-DC Converter

This paper presents a new super twisting sliding mode control for the isolated DC-DC bi-directional dual active bridge (DAB) power converter for enhanced output voltage regulation. The sliding mode control (SMC) is well known for its robustness and improved dynamics for non-linear systems. Still, it includes the drawback of high-frequency chattering and degradation of tracking performance. The suggested super twisting sliding mode control (ST-SMC) scheme incorporates the advantages of a sliding mode controller and eliminates the problem of chattering. Thus, improved dc-link voltage stability and high robustness for accurate reference voltage tracking are obtained. The output voltage in the DAB converter depends upon the power transferred through the transformer. The transferred power is a function of the phase shift of the voltage waveform of two H-bridges. The phase shift ratio is computed through the ST-SMC controller presented here utilizing the output voltage dynamic equation and power transfer equations for DAB converter. The proposed scheme which provides a robust control and an improved reference voltage tracking to the DAB converter performance. The proposed ST-SMC scheme is validated by simulation for 1 kW DAB converter in MATLAB-Simulink environment.