Open-Loop Control Methods for Interleaved DCM/CCM Boundary Boost PFC Converters

Open-loop interleaving methods for PFC boost converters operating at the boundary of discontinuous-conduction mode and continuous-conduction mode with a master-slave relationship are analyzed. It is shown that the only method that results in stable operation is the synchronization of the slave converter to the turn-on instant of the master converter, where each converter operates with current-mode control. Effects of mismatched inductances, phase-shift error, switching-frequency limit, and valley switching on the quality of the input current are discussed in detail.