Modeling and control of an AC-DC voltage source converter based on sliding mode and fuzzy gain-scheduling approaches

This paper proposes a fuzzy gain-scheduled Proportional Integral (PI) and second order sliding mode based control strategy of a two-levels and three-phase Voltage Source Converter (VSC) to adjust its DC-link voltage to constant level and to achieve unity power factor operation. The proposed control scheme has a cascade configuration which consists of an inner current loop based on a Second-Order Sliding Mode (SOSM) controller designed thanks to the known Super-Twisting Algorithm (STA). An outer voltage loop, based on a fuzzy gain scheduled PI algorithm, is investigated for the DC-link voltage dynamics regulation. Several demonstrative simulations are carried out and show the effectiveness and the robustness of the proposed control approach under the load variations.