A transformerless single-phase symmetrical Z-source HERIC inverter with reduced leakage currents for PV systems

A transformerless single-phase symmetric Z-source HERIC inverter featuring low leakage currents is presented in this paper. It is an attempt to utilize the Highly Efficient and Reliable Inverter Concept (HERIC) and an impedance source (Z-source) network to maintain a constant common mode voltage and thus low leakage currents in PV applications. The symmetric Z-source HERIC inverter requires two extra active switches. Nevertheless, the operation frequency of the two switches is the line frequency, leading to negligible losses. More importantly, the performance in terms of low leakage currents and harmonics is improved. Experimental tests are performed to validate the analysis and performance of the proposed system.