Sliding mode control for cascaded H-bridge boost rectifiers

Abstract

The control of cascaded H-bridge boost rectifiers is a challenging task, due to the inherent coupling of the H-bridge modules. This property highlights the demand for a robust control technique, appropriate for this nonlinear and non-minimum phase system. This paper introduces an approach that combines a deeper understanding of the system's power flow with the well known robustness of the sliding mode control theory. The system's control requirements are met and the employed algorithm allows for stable and independent control of each H-bridge. Moreover, the proposed control technique achieves unity power factor and precise regulation of the DC voltages, even in cases of different voltage references and/or loads. These characteristics are very interesting for power conversion applications in traction systems, battery chargers and uninterruptible power supplies.