A Family of Multi-Mode Rectifiers

Existing applications, such as photovoltaic systems and on-board power supplies, propose higher requirements for the gain range, efficiency, and power density of isolated dc/dc converters. However, the gain range of traditional isolated dc/dc converters is limited and the efficiency diminishes significantly when the input voltage mismatches. This article proposes a novel method to derive a family of multi-mode rectifiers based on basic structures, which is appropriate for many traditional isolated dc/dc converters. Each one can operate in various modes by adjusting the states of secondary switches. Combining the proposed rectifiers with different types of isolated converters, the input voltage range is widely expanded compared with conventional ones. Taking the LLC resonant converter with one of the proposed rectifiers as an example, a 250 W 38∼120 V input, 500 V output prototype is developed and tested, with a peak efficiency of 98.196%. Zero voltage switching and zero current switching are realized to ensure high efficiency. Compared with similar LLC converters with secondary rectifiers, the proposed one's own a much wider gain range and higher efficiency with fewer devices. Experimental results correspond to theoretical analysis and verify the effectiveness of the proposed rectifiers.