A Modular Multi‐Port Hybrid Solid‐State Transformer for Large‐Scale Renewable Power Applications

ABSTRACT Offshore wind and solar energy have substantial attention for the generation of high‐voltage ac (HVAC) and high‐voltage dc (HVDC). However, traditional systems face application limitations due to low‐frequency transformers and inefficient power converters. This article proposes a four‐port solid‐state transformer (FPSST) to enhance large‐scale energy generation from renewable sources. The FPSST incorporates a modular multilevel converter to collect both medium‐voltage ac and dc from wind and solar systems. Following this collection, high‐frequency transformer‐based dc/dc converters ensure galvanic isolation between ports by enabling a compact, lightweight and efficient design due to the advanced magnetic material. A cascaded H‐bridges multilevel inverter produces HVAC with reduced harmonic distortion and precise voltage regulation. Moreover, a series‐connected two‐quadrant converter generates HVDC, providing a stable dc output through a discretised dc‐link capacitor. The performance of the proposed FPSST is thoroughly investigated using the MATLAB/Simulink platform, which offers insight into system behaviour. Prior to experimental validation, an amorphous alloy‐based high‐frequency transformer is developed in the laboratory, and a 1‐kW sealed‐down FPSST is constructed. Simulation and experiment results confirm the feasibility and effectiveness of the proposed FPSST. Thanks to its compact, modular design, the four‐port SST can be easily scaled, enabling both HVAC and HVDC generation from renewable sources.