A fuzzy-controlled active power factor correction and voltage regulation scheme

Conventional rectifiers with passive output filters and feeding dc loads cause large distortions in the input line current. Consequently the power factor on the ac supply side is lowered and the quality of the ac supply voltage may be significantly degraded. However, Active Power Factor Correction (APFC) systems based on switchmode converters can shape the ac supply current so as to achieve near unity power factor, while regulating the load voltage. In this paper, we present a fuzzy controlled APFC which caters for the nonlinear characteristics of the converter. The performance of the proposed scheme is compared against a linear Proportional + Integral (PI) regulator under the same test conditions.