A novel PFC buck chopper for single-phase with single switching device

It is well known that non-linear rectifiers generate various harmonics in the power system. To improve those harmonic problems, a lot of original PFC circuits have been proposed so far. Among these, Takahashi, et al, have proposed a PFC scheme using single switching device for single phase boost chopper. For a buck chopper, however, it is difficult to realize the buck chopper in a usual way using single switch. On the basis of this scheme, we devise another PFC circuit. This method attempts to improve the input current, towards nearly sinusoidal waveform by using an intermediate capacitor circuit, whose operating mechanism is analogous to the conventional one having capacitor filter, but an original one. Various fundamental operations are discussed and these are confirmed by computer simulation. Compared with the conventional circuits, it is required fairly large capacitors, but the output power can be much increased in addition to improved THD.