A Novel Three Level Full Bridge Resonant Dc-Dc Converter Suitable for High Power Wide Range Input Applications

To make downstream dc-dc converters compatible with both single and three phases PFC stages for system integration, a novel three-level full bridge resonant dc-dc converter was proposed. This converter combines the LLC topology, which maintains merits as ZVS for all primary side main switches and ZCS for secondary side diodes under wide range inputs, and the three-level technique, which is suitable for high voltage input applications, together. In addition, full bridge configuration endows the high power capability to the proposed converter. The detail operation principles, as well as the design considerations and loss calculation, were presented. The validity and applicability were also verified by a 1kW prototype, while the maximum efficiency reaches 96.2%. Therefore, the proposed converter is very attractive for the system integration applications which have requirement to be compatible with 400V and 800V PFC systems, while high power capability must be taken into account. Consequently, it is of practical significance for industry to simplify power supply´s variety and lower cost.