Sliding mode control for cascaded H-bridge boost rectifiers

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.