Robust Adaptive Feedforward Sliding Mode Current Controller for Fast-Scale Dynamics of Switching Multicellular Power Converter

Abstract

Higher efficiency and lower losses are widely considered as the best metrics to optimize, in a high-power converter performance context. To provide a solution to the ever-increase of high switching frequencies challenges, we must explore soft-switching technologies to resolve interface issues and reduce the switching losses. This manuscript describes a comparative analysis between the fixed-bandwidth (FBW) and the variable-bandwidth (VBW) of the hysteresis modulation (HM) based on the conventional sliding mode (CSM) strategy. The two adopted techniques are applied to a bidirectional multichannel DC-DC asynchronous Buck converter. The cells are parallel-connected and operating in continuous conduction mode (CCM). The objective is to have a system that is more stable, more efficient and able to cope with variations in input voltage, load and desired output voltage. That requires, first, to attenuate the non-linearity phenomenon of the conventional sliding mode by placing a hysteresis modulation. Then, after applying this technique, we confronted the dilemma of the variable switching frequency. Our hypothesis was to incorporate a variable bandwidth of the hysteresis modulation. The results obtained under parametric variation clearly show the areas where significant differences have been found between the two approaches. Likewise, they both share several key features. Simulation studies in the MATLAB ® / Simulink ™ environment are performed to analyze system performance and assess its robustness and stability.