A Redundancy-based scheme for balancing DC-link voltages in cascaded H-bridge rectifiers

A new voltage balancing algorithm is introduced for cascaded H-bridge rectifiers. This kind of converter is made of a series connection of H-bridge cells with separate dc-links. The proposed balancing algorithm will regulate the voltage of all dclinks to the desired reference value, even if the attached loads are very different. The input current is also programmed to be sinusoidal and has low distortion, while the switching frequency is kept low at 1 kHz. In addition, the input power factor can be controlled. The simulation and experimental results are presented to confirm the validity of the proposed algorithm.