(A) new high efficiency multi-level half-bridge converter

Abstract

Nowadays, power supply market needs the server power supply with high power density and high efficiency. To meet this trend, many researches are conducted in power companies and many of them are focused on the DC/DC converting part in a server power supply. There are two types of converter topologies which are widely used in middle power application, conventional half-bridge converter and asymmetric half-bridge converter. However, these two types of converters have critical problems. Symmetric half-bridge converters operate under hard switching condition, which cause severe EMI problem and heat problem. In asymmetric converters, DC offset current which degraded transformer utilization is existed. The proposed A ZVS four level half-bridge converter with small output filter inductor overcome those problems which are showed in symmetric and asymmetric half-bridge converters by employing auxiliary transformer and auxiliary switches. Also the proposed converters have less stress on power switching components and have smaller output inductor. The operational principle, ZVS condition and output filter analysis are presented. Experimental results are demonstrated to verify the feasibility and advantages of the new topologies.