Abstract

Phase-shifted pulse width modulation (PS-PWM) is one of the preferred modulation strategies for cascaded H-bridge (CHB) converters due to its excellent harmonic performance. Nevertheless, this modulation strategy needs a fast sampling frequency, which can increase with the number of H-bridge sub-modules (SMs). Moreover, the advantages related to the harmonic content of the output voltages are usually lost for applications that require unbalanced operation conditions regarding SM power or voltage references, such as solar PV or battery energy storage systems. This work proposes a feed-forward compensation technique that reduces the sampling frequency to two times the carrier frequency while maintaining the good harmonic performance of the CHB output voltages. Simulation results are carried out to compare and demonstrate the superior performance of the proposed technique.