In this paper, an innovative approach of integrating multiple doubly-fed induction generator (DFIG)-based wind turbines using a single multi-port converter unit, named as a unified expandable power converter (UEPC) is presented. A novel partial simultaneous space vector modulation (PSSVM) scheme, adopted to the unified structure, is proposed to enhance the operational efficiency and DC-link utilization. The unified configuration can integrate two or more DFIGs through a multi-port converter in a cost-effective and efficient way. The unified structure enjoys compactness, plug & play capability, fewer switches, and a lower installation cost. Comparing with the conventional sequential space vector modulation (SSVM), which only uses the individual active vectors, the proposed PSSVM can utilize common active vectors between different ports, which is the main salient feature of this method. The performance of PSSVM is also validated via an OPAL-RT real-time simulator. The real-time outcomes prove that the proposed PSSVM can improve the DC-link voltage utilization and switching loss compared with the SSVM. The effectiveness of the proposed PSSVM based unified configuration in both normal and faulty conditions are evaluated and compared with the conventional structure using MATLAB/Simulink. The simulation results endorse the finding that regardless of the shared switches in the unified expandable power converter, the independent control and maximum power extraction from the wind are guaranteed using the proposed PSSVM.

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