Offshore wind energy systems using high frequency isolated current-fed modular converters

In this paper a new offshore wind energy power conversion architecture with grid integration using HVDC link is presented. Multi-MW multiple three-phase winding Permanent Magnetic Synchronous Generators (PMSG) captures the offshore wind energy. Each of the three-phase winding of PMSG are connected to Current Source Converters (CSC) that are controlled by MPPT. The outputs of these CSCs are series connected to from an intermediate medium voltage bus. Modular Input Series Output Parallel (ISOP) Current-Fed High Frequency (CF-HF) DC-DC converter provides galvanic isolation to the outputs of series connected CSCs and isolates them from High Voltage Direct Current (HVDC) link. The outputs of CF-HF DC-DC converters from different Multi-MW PMSGs are series connected to form HVDC link. At the grid interface, ISOP connection of CF-HF DC-DC converter modules are employed to provide isolation and to maintain a constant HVDC-link current. Voltage source converters (VSC) connected to the output of the DC-DC converters provides grid interface. Control and modeling of the proposed system are detailed. Simulation results demonstrate the proposed power conversion architecture control and operation.