DC Output Ripple Suppression of High-Frequency DC-DC Resonant Converter

Increasing switching frequency can greatly improve power density of dc-dc power converter, while meets challenges of significant high-frequency dc output ripple. The capacitor filter is a most cost-effective suppression for the output ripple. However, the capacitor parasitic parameters will deteriorate the suppression. The frequency characteristic of the capacitor filter was analyzed by considering the parasitic parameters. Then, a novel parallel dual capacitors filer is proposed, which creates the reverse coupling between the two adjacent capacitors of the filter by constructing opposite current flowing through the capacitors. Using the novel dual capacitors filer as a cell, a novel compact multicapacitors filer of V-shape is further extended. The insert gain test and the prototype with 20 MHz of switching frequency are constructed, and the experiments verified that the novel filters suppress the ripple by maximum about 50% comparing with the traditional capacitor without adding volume and cost.