Power Balancing Approach for Modeling and Stabilization of DC Networks

We propose a set of theoretical and practical tools for the stabilization of dc networks. In order to do so, we propose a new framework to study the dynamics of dc grids-one that permits the combination of power converter models with those impedances-directly in higher-order terms. This mathematical setting includes a convenient modeling specification that allows one to analyze complex high-gain converter topologies and to develop an energy-based stability analysis for dc grids with potential destabilizers such as loads with negative impedance characteristics (e.g., constant power loads). We show that instability problems arise due to a power imbalance between passive and non-passive loads, hence power balancing is a suitable stabilizing mechanism. Moreover, a low-cost hardware solution that ensures stability is provided in the form of a lossless (H-bridge) stabilizing filter. The new theoretical results, combined with the proposed implementation, offer a low-cost alternative with respect to other (battery/super-capacitor) energy-storage-based existing strategies. Experimental results based on a high voltage gain quadratic converter feeding multiple non-passive loads are included.