Design and control of modular multilevel DC converter (M2DC)

DC/DC converters are necessary in HVDC networks to adapt different voltage levels, different configurations or to participate in power flow control. This paper focuses on a recent DC/DC converter topology, called Modular Multilevel DC Converter (M2DC), which uses direct DC/DC connection without galvanic separations. A general analysis of the topology is firstly discussed. Afterwards a decoupled mathematical model, reducing the control complexity is proposed. To improve converter's performances and limit AC constraints on each leg, parameters adjust and inductor sizing are explored. Finally, simulation results are presented to validate the proposed decoupled model and the control. The impact of optimized parameters are shown on AC components values.