An Adaptive SPWM Technique for Cascaded Multilevel Converters With Time-Variant DC Sources

An adaptive sinusoidal pulse-width modulation (SPWM) technique for cascaded H-bridge (CHB) multilevel converters is presented in this paper. The proposed technique enables the CHB topology to provide a symmetrical ac voltage from a set of asymmetrical time-variant input dc-source voltages. A sensor-per-source (SPS) algorithm and a sensor-per-leg (SPL) algorithm are described as alternatives for implementing the adaptive SPWM technique. Software simulations and experimental results are presented to demonstrate the efficacy of the presented SPS and SPL algorithms.