New Framework for Optimal Current Sharing of Nonidentical Parallel Buck Converters

In this brief, parallel interconnection of buck (step-down) converters is considered. Classical control of such a topology uniformly distributes load current over branches. Yet, whenever nonidentical converters (having distinct characteristics) are considered, this brief demonstrates, both theoretically and experimentally, that minimizing overall losses requires nonuniform and even load-depend current distribution. In this context, a novel highly modular hierarchical control framework is proposed for arbitrary number of buck converters. Solutions for the two related design steps are given, which lead to a control law minimizing total losses as well as correcting voltage deviation for any operating point and without knowledge about load magnitude. Experimental results support our discussions.