A Dual Half-Bridge Converter With Hybrid Rectifier for DC Power Supply in Railway Systems

Dual half-bridge (DHB) converter is a recent innovation in the family of full-bridge converters, and it can achieve higher efficiency compared to the traditional converters. The DHB converters with center-tapped rectifier (CTR) and full-bridge rectifier (FBR) have been adopted in low (<; 100 V) and high (>200 V) output voltage applications, respectively. However, the output voltage is between 100 and 200 V in some applications, such as auxiliary railway dc power supply, both CTR and FBR can be the candidate and it is very indistinct to select the matched rectifier. To suit for such specific application, this article proposes a DHB converter with hybrid rectifier (Hyb-R). The Hyb-R is composed of a CTR section and an FBR section, which are connected in series by sharing two diodes. As a combined structure, the voltage stress of Hyb-R is between that of FBR and CTR, which makes Hyb-R well appropriate for dc power supply in railway systems. In this article, the operational principle and performance of the proposed converter are analyzed in depth. Three prototypes based on the DHB converters with CTR, FBR, and Hyb-R are built and tested, respectively. Experimental results show that the proposed converter can achieve a superior efficiency compared with other converters.