A New Bridgeless PFC Converter having Low Common-Mode Noise and High Efficiency for Server Power Application

Abstract

A bi-directional bridgeless PFC converter (BBPFC) is fascinating topology for high power application among many bridgeless PFC converters due to small EMI filter size and simple control method despite of floating gate driver. By varying reverse recovery characteristics of diodes placed on the conduction path, it is possible to improve EMI characteristics without reducing power density. Therefore, when BBPFC is applied to high power application such as server power supply, it can be seen that it has the highest EMI performance and the highest power density. However, the way to improve the common-mode (CM) noise through this topology is difficult to actually use because of the patent already registered. In this paper, an improved bridgeless PFC converter (BPFC) for avoiding patent already registered is proposed. By using this proposed converter, the power system can achieve high EMI performance and high efficiency. Moreover, it is very simple to implement because the proposed converter is not required for floating gate driver. Also, when applied in DC input voltage conditions, the proposed converter has better characteristic due to utilizing only one switch for build-up operation. The principle and analysis of the proposed method are presented. The performance and feasibility are verified by analysis and simulation results from the high line, i.e. 230 VRMSinput, 800W/400V output prototype.