Mesh-based architecture for DC microgrid control to achieve accurate current sharing among converters
Various examples are provided related to DC microgrid control. In one example, a system includes a mesh DC microgrid network having at least 4 microgrid DC nodes. The mesh DC microgrid network can be organized as clusters of three node DC microgrid systems, where each cluster include three of the at least 4 microgrid DC nodes. In each cluster, one of DC microgrid nodes is a pivot node that links remaining clusters together within the mesh DC microgrid network. Each DC microgrid node of the mesh DC microgrid network is directly connected to the pivot node. In another example, a mesh DC microgrid network includes one or two remaining microgrid DC nodes directly connected to a pivot node by a tie-line including a tie-line current sensor. One or more converters at the remaining DC microgrid nodes can be controlled using feedforward control with droop control using tie-line current sensor information.
1 . A system, comprising:
a mesh DC microgrid network having at least 4 microgrid DC nodes consisting of a pivot node comprising one or more converters connected to the pivot node and remaining DC microgrid nodes comprising one or more converters connected to at least one of the remaining DC microgrid nodes, the at least 4 microgrid DC nodes interconnected by tie-lines,
where the mesh DC microgrid network is organized as a plurality of clusters of three node DC microgrid systems, wherein each cluster comprises three of the at least 4 microgrid DC nodes,
wherein, in each cluster, one of the DC microgrid nodes is the pivot node that links remaining clusters together within the mesh DC microgrid network, and
wherein each remaining DC microgrid node of the mesh DC microgrid network is directly connected to the pivot node by a respective one of the tie-lines comprising a respective tie-line current sensor,
where the one or more converters at respective remaining DC microgrid nodes are each controlled using droop control having a feedforward voltage offset generated based at least in part upon respective tie-line current sensor information and cable resistance of the respective tie-line directly connecting the respective remaining DC microgrid node to the pivot node,
where the one or more converters at the pivot node are each controlled using droop control having a zero feedforward voltage offset.
2 . The system of claim 1 , wherein each microgrid node in the mesh DC microgrid network has a redundant current path.
3 . The system of claim 1 , wherein the feedforward voltage offset for the one or more converters at the remaining DC microgrid nodes is generated based at least in part upon prior estimates of cable resistances of the tie-lines.
4 . The system of claim 1 , wherein the system is enabled to provide current sharing among the DC microgrid nodes without using a communication network to exchange information between converters.
5 . The system of claim 1 , wherein the mesh DC microgrid network comprises 5 or more microgrid DC nodes.
6 . The system of claim 1 , wherein the pivot node does not comprise a load connected to the pivot node.
7 . A system, comprising:
a mesh DC microgrid network having three microgrid DC nodes comprising a pivot node comprising one or more converters connected to the pivot node and two remaining microgrid DC nodes, the two remaining microgrid DC nodes comprising one or more converters connected to at least one of the two remaining microgrid DC nodes, each of the two remaining microgrid DC nodes directly connected to the pivot node by a respective tie-line comprising a respective tie-line current sensor,
where the one or more converters at the two remaining DC microgrid nodes are each controlled using droop control having a feedforward voltage offset generated based at least in part upon respective tie-line current sensor information and cable resistance of the respective tie-line directly connecting the respective two remaining DC microgrid nodes to the pivot node,
where the one or more converters at the pivot node are each controlled using droop control having a zero feedforward voltage offset, and
the system is enabled to provide current sharing among the three DC microgrid nodes without using a communication network to exchange information between converters.
8 . The system of claim 7 , wherein the feedforward voltage offset for the one or more converters at the remaining DC microgrid nodes is generated based at least in part upon prior estimates of cable resistances of the tie-lines.
9 . The system of claim 7 , wherein the two remaining microgrid DC nodes are connected to each other by a tie-line.
10 . A system, comprising:
a mesh DC microgrid network having two microgrid DC nodes comprising a pivot node comprising one or more converters connected to the pivot node and one remaining microgrid DC node comprising one or more converters connected to the one remaining microgrid DC node, the one remaining microgrid DC node directly connected to the pivot node by a tie-line comprising a tie-line current sensor,
where the one or more converters at the one remaining DC microgrid node are controlled using droop control having a feedforward voltage offset generated based at least in part upon tie-line current sensor information and cable resistance of the tie-line,
where the one or more converters at the pivot node are each controlled using droop control having a zero feedforward voltage offset, and
the system is enabled to provide current sharing among the two DC microgrid nodes without using a communication network to exchange information between converters.
11 . The system of claim 10 , wherein the feedforward voltage offset for the one or more converters at the one remaining DC microgrid node is generated based at least in part upon prior estimates of cable resistances of the tie-lines.