Recent trends in renewable source integration and advancements in electric loads led to the emerging of local DC microgrids. However, due to majority of AC loads hybrid AC-DC microgrids are formed, incorporating feasible power converters as medium of power flow. Instead of conventional bidirectional AC-DC and DC-DC converters as interlinking converters in hybrid AC-DC microgrid, an open-end transformer based multilevel converter configuration is proposed as interlinking converter in this paper. The converter configuration includes two converters concatenated with primary of transformer, is a unique substitution for conventional multiple converters utilized. The salient features of the configuration include reduced control complexity, inherent isolation from AC grid, and able to provide inter-grid bidirectional power flow. A modified control scheme is proposed for precise power flow control in the system. Real time simulation of the proposed configuration of hybrid AC-DC microgrid is implemented in RSCAD/RTDS and experimented on a scaled hardware prototype. The outcomes depict the potency of control scheme in inter-grid power flow control.
K. C. Bandla and N. Prasad Padhy, "A Multilevel Dual Converter fed Open end Transformer Configuration for Hybrid AC-DC Microgrid," 2018 IEEE Power & Energy Society General Meeting (PESGM), Portland, OR, 2018, pp. 1-5.
KEYWORDS: inverters, power conversion, microgrids, voltage control, windings, renewable energy sources