Electrolytic Capacitor-less Single-stage AC/DC Converter With Controllable Rectifier Circuits

An efficient and reliable power-supply system is the key point for the data center operating stably.AC/DC converter is a significant part of the power supply for the data center.The two-stage constitution of a traditional AC/DC converter includes a power factor correction circuit and a DC/DC circuit.Usually,a large-capacity electrolytic capacitor is used as an energy storage capacitor to absorb the inherent double frequency power ripple of the AC power supply.However,this kind of structure will affect the reliability of the AC/DC converter as well as its lifespan.Single-stage AC/DC converter can be also called a single-stage PFC converter,which has the advantage for its simple structure.In recent years,it has attracted widespread attention from the academic community.Therefore,the electrolytic capacitor-less single-stage PFC converter has become the trending research domian.This paper proposes an electrolytic-free single-stage PFC converter with controllable rectifier bridge.The controllable rectifier bridge of the PFC converter can control the energy flowing from the energy storage capacitor to the load in one switching cycle,thereby realizing power decoupling.Compared to other power decoupling schemes,this topology benefits with its simple control method and it does not consist additional passive components.This paper first introduces the structure and working principle of an electrolytic capacitor-less single-stage PFC converter with a controllable rectifier bridge,and a detailed theoretical analysis of the converter is carried out,along with the parameters of all power devices in the converter.Then the control strategy of the proposed PFC converter is introduced and the specific DSP designnig scheme is given.Additionally,the input voltage direction dectecting circuit,voltage sampling circuit,MOSFET driving circuit and the protection circuit are also mentioned in this paper.Finally,the effectiveness of the control method for the proposed single-stage PFC converter is verified through the joint simulation of MATLAB/Simulink and PLECS.An experimental prototype of a 280 W single-stage PFC converter is built to verify that the new single-stage PFC converter proposed in this paper can reduce the capacity of the energy storage capacitor required by the converter,and then replace the original large-capacity electrolytic capacitor with a ceramic capacitor with higher reliability and longer lifespan.