Bridgeless power factor correction (PFC) operation is enhanced with a phase locked loop (PLL) providing synchronization and a current reference with no distortion. PLLs using a quadrature signal generator (QSG) provide information to generate a faster feedforward (FF) compensation for the grid amplitude variations with higher gain than when the FF signal, ff, comes from the rectified grid voltage. However, the square of the transfer function (TF) involved in the generation of the ff is applied in the denominator of the FF TF, so that delays and integrators used to obtain the ff cause propagation of the grid amplitude perturbation and non-zero steady state error at the output. This work presents a novel extended application of the two-sample PLL (2SPLL) with the QSG based on a differential function that solves this limitation with wider bandwidth to compensate for grid voltage sags.
