Efficiency Comparison of Three-Phase Four-Wire Inverter Topologies for Unbalanced and Nonlinear Loads

The transition of the energy system to renewable energy sources led towards a higher penetration of distributed energy production. Therefore, inverters have to provide a growing amount of grid services, like reactive power compensation, load balancing and harmonic elimination. In this paper, a three-leg and a four-leg four-wire inverter topology for grid building voltage source inverters for unbalanced and nonlinear loads are compared. Simulation results of the inverter efficiency at different operating points and the impact of the two topologies onto the DC-Link capacitors are presented.