S.K. Panda, J. Saha
National University of Singapore,
Keywords: solid-state-transformer, hybrid nanogrid, energy efficiency
Summary:Failure of isolated power electronic equipment causes a lot of downtime, substantial maintenance period and associated losses. Our new topology inherently has a lower failure rate due to decrement in the number and size of electrolytic capacitors used. We developed Modular Matrix-Based Solid-State-Transformer topology for controlled energy interactions between the utility grid and a hybrid nanogrid (consisting of both AC and DC distribution grids). The innovative topology coupled with modulation scheme exhibits high power-density, good utility grid-side power quality and higher reliability compared to other conventional Solid-State-Transformer topologies. Our topology can perform a single stage AC-DC/DC-AC conversion and is found to have certain advantages. Firstly, it eliminates one electrolytic capacitor by facilitating a single stage LFAC to HFAC conversion in the front-end MC. The current ripple cancellation after the CDR, leads to a reduction in capacitor size. Both of these contribute to an increase in reliability. Secondly, due to the reduction in number of components and the reduction in capacitor volume, the power density of the proposed topology is quite high. Lastly, the proposed converter draws a current with lower harmonic content which is attributed to the modulation scheme of the topology. In addition, the AC/DC conversion stage of our topology can be very relevant for battery charging (compact and reliable chargers) and for integration of renewable energy sources and distributed energy storage through the Nanogrid’s DC bus.