Every solar-plus-storage system has to answer a wiring question: how do the panels, the battery, and the load share power? US20210135577A1, published May 6, 2021, claims one answer — a multi-port DC/DC converter that gives each asset its own port on a common DC bus.

The CPC tags are tight: H02M 3/1584 (DC-DC conversion with multiple outputs) and H02M 1/14 (means for reducing ripple). This is a topology patent — it is about the architecture of the converter, the arrangement of ports and switches that lets power flow between several DC sources and sinks through one shared stage.

“A non-isolated multiport DC/DC converter topology is provided. The non-isolated multiport DC/DC converter topology is modular and can incorporate an unlimited number of independent input or output ports.”— U.S. Patent Application 2021/0135577 A1 source

Why this maps to the grid: DC-coupled solar-plus-storage is increasingly preferred because it avoids converting DC to AC and back when charging a battery from panels. A multi-port converter is the enabling component — it lets the array charge the battery directly on the DC side and serve the load or the grid through a single inversion. Fewer conversions means fewer losses and lower cost.

The patent claims a topology, not a product or a deployment. It does not fence off DC-coupled storage as a concept — many topologies achieve multi-port conversion. It fences off one arrangement, and its value depends on whether that arrangement is more efficient or cheaper than the alternatives.

From patent to grid: the unglamorous component IP — converter topologies, port arrangements, ripple reduction — is what actually determines the cost and efficiency of the solar-plus-storage systems clearing interconnection queues. A 2021 multi-port converter publication is a small upstream artifact of the DC-coupling trend now dominant in new installations.