Study Of High Efficiency Totem-pole Bridgeless PFC Converter

Power electronic technology is widely used in daily life and industrial applications.It brings convenience to humans and also causes certain difficulties in the harmonic control of the power grid.This makes power factor correction(PFC)especially important in modern high-quality rectification systems.With people’s pursuit of high efficiency and high power density for power electronic devices,bridgeless converters are gradually becoming a research hotspot in the field of PFC because of their superior characteristics.In this paper,we first give an overview of PFC technology,analyze various bridgeless PFC converter characteristics and application scenarios,and then compare and analyze their respective operating principles,common mode noise,driving methods and the number of semiconductor devices.Finally,the Totem-Pole bridgeless PFC(TPBL PFC)converter is deeply studied.TPBL PFC converters have lower common mode noise than other bridgeless topologies because the input end is clamped by diodes to the output every power frequency cycle;At the same time,the lower number of components and higher device utilization make it more valuable for engineering applications.However,due to the poor reverse recovery characteristics of the parasitic diode of the silicon-based MOSFETs,the TPBL PFC converter can only operate in discontinuous conduction mode(DCM)or boundary conduction mode(BCM).In recent years,with the development of new devices,TPBL PFC converters composed of Ga N MOSFETs can work in continuous conduction mode(CCM)because they have no reverse recovery problem,which has attracted the attention of academia and engineers.However,Ga N MOSFETs are currently mostly used in low-power converters.High-power Ga N devices not only have fewer product types and are expensive,but also have the risk of performance degradation and lower reliability,which limits their further applications.This paper proposes a TPBL PFC converter with Zero-Voltage Switching(ZVS)and Zero-Current Switching(ZCS)that can work in CCM.Based on the traditional Totem-Pole bridgeless PFC,this topology realizes the ZVS turn-on of the power switches(MOSFETs)by adding an auxiliary resonant branch.At the same time,the auxiliary resonant branch can effectively suppress the di/dt of its body diode current.To achieve ZCS turn-off,greatly alleviating the MOSFETs body diode reverse recovery problem.For the auxiliary resonant branch that works in the DCM,its switch tubes can realize zero-current turn-on,and all the switch tubes of the converter work in a soft-switching state.This topology overcomes the MOSFET body diodes reverse recovery problem of traditional silicon-based TPBL PFC and the limitation that it can only work in DCM or BCM,broadens its operating range,and has higher efficiency and power density compared with the traditional TPBL PFC circuit.Finally,based on the analysis of the operating principle and steady-state characteristics of the proposed converter,an experimental prototype with an switching frequency of 100 k Hz and a power of 1 k W was designed.The experimental results show that the converter prototype achieves the soft switching function in the full input voltage range(150Vac～220Vac),and the PF value is greater than 0.97,and the efficiency reaches 96.4% at full load,which verifies the feasibility and effectiveness of the topology scheme.