Research On Dual-Resonance-Core-Based Switched-Capacitor Topology And Its Applications In PFC Converter

As the country strengthens its strategic deployment in the new energy vehicle industry,new power electronics technologies for new energy vehicles have become a research hotspot in the power electronics industry in recent years.In the power system of new energy vehicles,especially electric vehicles,there are AC-DC power conversion for battery charging,DC-AC power conversion for motor drive,and DC-DC converter for DC bus.This article focuses on the innovative technologies in the AC-DC and DC-DC conversion stages.In view of the increasing demand for wide-gain,high-power-conversionefficiency,and high-power-density converters in the DC-DC conversion stage,a dualresonant switched capacitor DC-DC converter topology on the basis of previous research is analyzed in this paper.Its Boost-type operating mode based on pulse-overlapped fixed resonant time modulation technology is proposed which enables it to have wide stepup/down,high-power-conversion-efficiency,and high-power-density operating characteristics.At the same time,for the application of lithium-ion battery charging under asymmetric voltage gain,the basis and procedure for parameter design of the dual-resonant switched-capacitor step-up/down converter are further proposed in this paper based on the consideration of the maximum duty cycle.So that better energy transfer efficiency and lower stress under asymmetric voltage gain can be achieved.Aiming at the DC bus voltage conversion in electric vehicles,a dual-resonance isolated DC transformer with anti-arm-break capability is proposed in this paper,and high efficiency and high density can be achieved.In order to solve the problems of synchronous rectification in the asymmetric mode and resonant point drift with working conditions,a dual-resonance point tracking strategy based on a fully isolated body diode conduction state detection circuit is further proposed in this paper.Focusing on the poor power factor correction performance caused by the weak voltage regulation capability when the traditional resonant switched-capacitor converter is applied to power factor correction,a step-down power factor correction rectifier based on the dual resonant switched capacitor topology is proposed with non-pulse-overlapped fixed resonant time modulation.The proposed rectifier can achieve higher power density,and its wide step-down range can introduce better power factor correction characteristics.In addition,in order to further improve the energy conversion efficiency,the derivative topology without diode bridge is further proposed in this paper,and its operating principle and working characteristics are analyzed and verified.