Design Constraints Generalization for Series-Stacked Buffer-Based Active DC Links

Series-stacked buffer (SSB)-based active dc links aim to increase power density by replacing bulky dc link capacitor with series connection of significantly lower valued capacitor and auxiliary bidirectional dc/ac converter. SSB design constraint describing quantitative relation between passive components values and system power rating was established to achieve minimal remaining dc link voltage ripple magnitude. This letter generalizes the above requirement, revealing that allowing nonminimum magnitude of residual dc link voltage ripple releases other design constraints, yielding a more optimal solution in terms of full-rating capacitance utilized and/or auxiliary bidirectional dc/ac converter volt-ampere rating. Experimental results validate the proposed methodology, matching corresponding analytical predictions.