New Coupled Inductor Rectifier With Low Voltage-Rated Diode for Low Conduction Losses in Phase-Shift Full-Bridge Converter

A phase-shift full-bridge converter with a coupled inductor rectifier (CIR) has been introduced to eliminate the primary circulating current and reduce the voltage stress on rectifier diodes. However, a small magnetizing inductance is inevitably used due to low zero-voltage-switching (ZVS) current, and some diodes still suffer from high voltage stress. In addition, during the freewheeling period, the output current flows through the high voltage-rated diodes. Therefore, high conduction losses occur from the transformer and rectifier diodes. To solve these problems, a new rectifier with low voltage-rated diodes is proposed. Since the ZVS current is increased, large magnetizing inductance can be employed. Furthermore, the output current flows through the low voltage-rated diodes. Consequently, the proposed rectifier effectively reduces conduction losses compared to the conventional CIR. A 700 W prototype was implemented to validate the effectiveness of the proposed converter.

I. Introduction

Dc–dc converters with a wide input voltage range are essential for various applications, such as electric vehicles and renewable energy systems [1], [2], [3]. For high efficiency in medium-to-high power applications, LLC, dual-active-bridge (DAB), and phase-shift full-bridge (PSFB) converters are commonly used [4], [5], [6], [7], [8], [9], [10], [11], [12], [13].