Two-phase Interleaved Boost PFC Converter With Coupled Inductor Under Single-phase Operation

Boost converter is widely used in PFC(Power Factor Correction)application for small input current ripple and high power factor.By using the interleaving technology,the equivalent switching frequency is increased and the input and output current ripple is reduced,which expand the application of the boost PFC converter to higher power.Furthermore,for high power density and high efficiency requirements applications,coupled inductor are usually used in interleaved boost PFC converter to reduce the volume of the magnetic component,as well as the ripple of the inductor current.Although the interleaved boost converter is usually designed for high power applications,the converter does not always work at full load.When the converter operates at light load,the interleaving technology increase the number of cells working in parallel which increase the loss of the converter.The phase-shedding control,which dynamically change the number of active phases at light load,is a common method to optimize the system efficiency in all load range.However,when the inductors are coupled,the coupling effects may make the operating phase and non-operating phase influence each other,which make the operation mode,efficiency and PF change.In this paper,the interleaved boost PFC converter with coupled inductor in single-phase operation is analyzed.The operation modes of the converter in both switching cycle and a half line cycle are discussed.Furthermore,the power distribution between two phases and PF is analyzed.Finally,a 1200 W prototype is built and tested in the lab to verify the analysis.