Design Optimization of a Two-Phase Interleaved Transition Mode Boost Converter for Power Factor Correction

The prominence of interleaving power converters arises from the need for more efficient power supplies and higher power densities. Together with this is the difficulty of such converters to pass efficiency and power factor requirements of 80 Plus certifications and European Commission Energy-related Product (ErP) Ecodesign Directives at light-load conditions due to domination of switching losses over conduction losses. This study demonstrates a method to optimize the design of a two-phase interleaved boost converter operating in transition mode for power factor correction (PFC) applications. As phase shedding was introduced to increase the light-load efficiency, the converter's phase shedding level was adjusted to comply with efficiency standards. The power factor was optimized considering the capacitances of a differential mode electromagnetic interference (EMI) filter. While the theoretical efficiencies of the converter with respect to different phase shedding levels were presented, the power factors with respect to different X-capacitor (X-cap) sizes were also provided. A 350W-prototype was built to verify the analysis and it shown that phase shedding level and size of X-cap affected the efficiencies and power factor at light-load conditions, respectively.