Two-Phase Interleaved Critical Mode PFC Boost Converter With Closed Loop Interleaving Strategy

This paper presents a two-phase interleaved critical mode (CRM) power factor correction (PFC) boost converter with a novel closed loop interleaving technique. This new interleaving technique makes each phase work at ideally CRM. Natural current sharing and precise 180 degrees phase shift are achieved. The scheme can be easily integrated into a PFC control chip. Full-order averaged model of CRM boost is derived to analyze the stability of the converter. The loop response and stability of the closed-phase regulation loop have been analyzed. A 400 W two-phase interleaved CRM PFC boost converter prototype is built. This proposed scheme is verified by simulation and experimental results.