A modulation strategy for wide voltage output in DAB based DC-DC modular multilevel converter

This paper presents a modulation strategy for wide voltage output in a bidirectional modular multilevel dc-dc power electronic converter for wave energy extraction using Electro Active Polymer Wave Energy Converters (EAPWECs). The chosen electrical power converter uses a 10 kV, low current bidirectional dc-dc modular multilevel topology with Dual Active Bridges (DABs) as a basis for each module. This paper proposes a modulation method consisting of several variable frequency DAB modulation modes and explains their operating areas and limitations. Through a simulation model it is shown how the control for the multilevel converter is implemented. Finally, loss estimation is performed using the developed loss model, which was previously validated on an experimental setup.