A Control Circuit With Load-Current Injection for Single-Phase Power-Factor-Correction Rectifiers

A load-current-injection control technique for boost-derived power-factor-correction (PFC) rectifiers with average current-mode control is proposed in this paper. By adding a load-current loop to the conventional inductor current loop, the output voltage response to load steps is speeded up, almost eliminating the typical voltage overshoots of this kind of converters. Although the techniques based on the load-current injection are traditionally called "load feedforward," this paper shows that an additional feedback loop, which modifies the linear small-signal model of the converter, is also introduced. In order to validate the concept, a converter prototype working from a universal input line has been designed and tested, showing that a very fast dynamic response of PFC rectifiers may be achieved in a cost-effective way