Real-time power flow control using DVR-based hybrid transformers

This paper presents a three-phase power flow control method utilizing a dynamic voltage restorergulat, which combines a back-to-back inverter and a series injection transformer. The proposed method employs a digital control processor-based algebraic algorithm to solve complex non-linear power equations from the output voltage and phase of the series injection transformer, which are derived in real time. This allows for a precise power flow, even in the presence of grid voltage fluctuations. In addition, the proposed phase balancing technique addresses the power imbalances caused by unbalanced lines, enabling equal power delivery to each phase. Experimental validation with a hardware prototype demonstrated the ability to control the power flow up to 60 kVA under balanced conditions and 20 kW/10 kVA under unbalanced conditions between grids.