Digitally controlled open-loop master-slave interleaved boost PFC rectifier

In this paper, a digital control method for open-loop interleaving technique for two-phase critical conduction mode (CRM) boost power factor correction (PFC) rectifier is proposed. The proposed control method guarantees the exact phase shift between master and slave module, as well as proper soft switching of slave MOSFET. The phase shift between the modules is maintained in any time including the transient operation, but slight time deviation of turn-on instant of slave MOSFET may occur as a trade-off. The control circuit requires simple logic elements and digital control ICs, and does not require any two-loop control calculation and phase-locked-loop. The performance of the proposed control method is verified by 500-W laboratory prototype hardware.