An open-end winding hybrid transformer

This paper deals with a novel hybrid transformer configuration able to face power quality issues occurring on modern distribution grids integrating distributed generation from renewable energy sources and non-linear power electronic loads. The proposed system encompasses a three-phase distribution transformer with secondary windings arranged according to an open-end configuration and a three-phase inverter with floating DC bus. Unlike previous hybrid transformers the proposed one does not require a bidirectional converter to manage bidirectional power flows, neither a tertiary winding to supply the inverter, thus allowing the use of standard MV-LV distribution transformers with simple modifications. The obtained power conversion system can be exploited to perform a voltage control at the distribution grid edge, a reactive power management and harmonic pollution mitigation. Simulations confirm the effectiveness of the proposed solution, ensuring high power quality voltage control under unbalanced grid and load conditions.