Comparison of phase-shifted full-bridge converters with auxiliary networks

The phase-shifted full-bridge zero-voltage-switching (ZVS) converter is widely adopted in industry applications. But it also suffers some problems, such as narrow ZVS range, excessive duty cycle loss, large circulating energy, and severe parasitic ringing. A quantity of methods have been proposed to solve the aforementioned problems. In this paper, several typical auxiliary networks are classified and analyzed. Based on the analysis above, a new adaptive auxiliary network is proposed. The key performance of these topologies is studied and compared, and the duty cycle loss, auxiliary energy/current, and conduction loss of the lagging-legs are compared quantitatively. A prototype of the proposed converter is built to verify the analysis. Finally, the advantages and disadvantages of these auxiliary networks are summarized.