With the large-scale and far-reaching development of offshore wind farms

the offshore wind power all-DC transmission system has become one of the research hotspots. This article proposes a new series-parallel DC wind farm collection topology for offshore wind power all-DC systems

including series-parallel converter topology design for medium-voltage DC wind turbines to reduce submodule capacitor voltage ripple

which can be applied to medium-voltage large capacity DC wind turbines. Aiming at the problem of “wind abandonment” that is prone to occur in series wind turbines

a power balance converter is proposed to provide a flow path for the surplus power between series wind turbines

so that each wind turbine can achieve maximum power point tracking (MPPT) operation. Then

corresponding control and modulation strategies are designed for the proposed new offshore wind turbine full DC collection topology. Finally

the feasibility of the proposed topology and the effectiveness of the control and modulation strategies are verified through Matlab/Simulink simulation.