Coordination control for multi-voltage-level dc grid based on the dc–dc converters.

• A switch mode control and a dc–dc coordination control for dc–dc converters' coordinated operation is proposed. • Real-time coordinated control enabling automatic dispatch of the dc–dc converters. • The unbalanced power from one dc grid could be optimally distributed with proposed control. • The serious power fluctuation events could be prevented with proposed control. Dc–dc converters are emerging as a key device for future dc transmission networks. This paper develops a switch mode control and a dc–dc coordination control for dc–dc converters' coordinated operation in the multi-voltage-level dc grid. The switch mode control is a local controller on the dc–dc converter to enable the automatic switch of the dc–dc operation mode. The dc–dc coordination control is an advanced control based on the switch mode control. With the dc–dc coordination control, unbalanced power from one dc grid could be optimally distributed to other grids, in order to avoid serious power fluctuation events. Simulation results are provided to demonstrate the performance of the switch mode control and dc–dc coordination control. [ABSTRACT FROM AUTHOR]