Low-volume PFC rectifier based on non-symmetric multi-level boost converter

This paper introduces a universal-input digitally-controlled single-phase rectifier with power factor correction (PFC) based on a modified multi level boost converter topology. In comparison with the conventional boost-based systems and other multi-level solutions the new PFC rectifier has significantly smaller inductor and lower switching losses. The improvements are achieved by replacing the output capacitor of the boost converter with a non-symmetric active capacitive divider and by utilizing downstream converter stage for the divider charge balancing. Experimental results obtained from a 400W, 200KHz, universal input voltage (90V-260V) to 400V PFC prototype demonstrate three times smaller inductor current ripple, allowing for the same inductor reduction, and up to 50% reduction in power losses, resulting in 6% efficiency improvement compared to a conventional boost PFC.