Analysis of modular inverter-fed six-winding transformers for WECS-mains interface

The paper describes the analysis of Multi-Winding Transformers (MWTs), with inverter fed Low Voltage (LV) primary windings and with secondary windings paralleled to the Medium Voltage (MV) mains. Parallel or series inverter dc link connections can be used. Typical application fields are medium power Wind Energy Conversion Systems (WECSs), using modular components (multi-module generator and transformer). Design and modeling aspects of a Six-Winding Transformer (6WT) are investigated: arrangement of coils around the column; coils positioning in the window, FEM parameter identification. Then, the transformer performances are studied, considering inverter command parameters, sharing and waveform distortion of transformer and mains currents.