Back-to-Back Energy Router Based on Common-Ground Inverters

With the increase of domestic generation resources (mainly photovoltaic), and the use of storage systems in many buildings, the utilization of the dc system along with ac system is being developed. For this purpose, energy routers with multiple ac and dc ports are employed. By the way, there are not enough standards to integrate the dc systems into the ac grid and safety considerations are still a problem. Many studies suggest the use of an isolated system, but isolation comes with increased volume and cost. This paper proposes an energy router based on a back-to-back structure with common-ground inverters. Connecting the neutral wire of the ac system to the negative port of the dc link eliminates leakage currents and ensures safety. The proposed energy router uses two common-ground inverters. Each inverter has five switches and has the ability to increase/decrease the voltage and also operate in both directions. The operation mode of the common-ground inverter has been investigated and the simulation results using PLECS confirm the accuracy of the overall structure and benefits compared to classical H-bridge inverter.