Ripple steering AC-DC converters to minimize input filter

In this paper, a boost topology with a coupled inductor to achieve zero-ripple input current for power factor correction (PFC) application is proposed. By using a coupled inductor as the PFC transformer, this topology not only can comply with any standards or regulations, but it also provides clean power in a universal ac line (90 Vac to 264 Vac). The zero ripple current PFC topology is designed to work in critical conduction mode (DCM boundary) to eliminate diode reverse recovery loss and provide automatic control. This is done so that the complexity of the controller is reduced; the control strategy of PFC stage is similar to that of a conventional boost converter. By using a coupled inductor boost topology, one can remove electromagnetic interference (EMI) filter without sacrificing the input current harmonics. Consequently, smaller passive components can be used, and a lighter weight and lower cost can be achieved. Experimental results are given to confirm the theoretically predicted behavior.