Abstract

A novel high-efficiency double LLC resonant dc-dc converter with zero input current ripple and low voltage stress is presented. The input current ripple and undesired harmonic components can be significantly reduced without adding a large input filter. Moreover, all main switches and rectifier diodes are softly switched in a wide input voltage range, reducing the switching loss. The voltage stress on each main switch is only half of the input voltage by using the improved three-level structure, which enables the use of low-voltage-rated power switches for high-voltage input applications. The operation principle is analyzed and experimental results of a prototype validate the performance of the proposed converter.