Zero-Voltage Switching Full-Bridge T-Type DC/DC Converter with Wide Input Voltage Range and Balanced Switch Currents

With the development of silicon carbide (SiC) power devices, the circuit structure of power converter for high-voltage applications would be simpler and more compact because the two-level-based topologies become applicable. This paper proposes a full-bridge (FB) T-type isolated dc/dc converter for the applications with high input voltage and wide input voltage range. The proposed converter is composed of four main power switches with high voltage stress (SiC
mosfet
) and four auxiliary power switches with low voltage stress (Si
mosfet
). Comparing with the conventional diode clamped FB three-level isolated dc/dc converters, the proposed FB T-type converter has simpler circuit structure and higher efficiency. A corresponding control strategy including two working patterns is proposed, which can not only realize the zero-voltage switching for the main and auxiliary power switches but also satisfy the wide input voltage range. More importantly, the proposed corresponding control strategy has the ability of balancing the currents among the power switches, which would balance the power losses, thermal stresses among the power switches, and thus improve the reliability of the converter. The characteristics and performances of the proposed converter with the corresponding control strategy are analyzed in detail and verified by the simulation and experimental results.