Novel single-phase transformerless inverter based on the freewheeling loop separation for PV systems

Transformerless inverters are widely used in low-power single-phase grid-connected PV systems, because of its high efficiency, low price, light weight, small volume. However, it is a big problem that the dangerous leakage currents appear without using transformers. This article proposes a novel transformerless inverter using a novel idea of the freewheeling loop separation for PV system to protect the system from dangerous leakage currents, and the new topology is analyzed with operation modes. Then a simulation using Matlab/Simulink is built for Heric topology and the new topology to verify the operation principle and compare both performances in the aspect of leakage currents characteristics. Finally, the simulation results show that the performance in leakage currents of the proposed topology is better than HERIC topology.