A simple line-frequency commutation cell improving power factor and voltage regulation of rectifiers with passive L-C filter

The paper presents a simple cell with a line-frequency commutated AC switch that is able to greatly improve both power factor and output voltage regulation of rectifiers with passive L-C filters. The boost action introduced by the commutation cell allows for the compensation of the voltage drop across the input filter inductor, so that output voltages higher than the peak of the line voltage can be achieved. Moreover, as compared to the line-frequency commutated boost rectifier, the proposed circuit allows compliance with the low-frequency harmonic standard EN 61000-3-2 with a lower filter inductance value, at output power levels greater than 1 kW. A converter prototype was built and tested. Results are reported in order to confirm the theoretical analysis.