A Six-Switch Five-Level Transformer-less Inverter without Leakage Current for Grid-Tied PV System

A novel Six-Switch Five-Level Common Ground Transformer-less (6S-5L CGT) inverter is proposed in this paper. It is utilizing only one input dc voltage source which is applicable for photovoltaic systems. The important merits of the novel proposed 6S5L CGT inverter are: i) inherently elimination of leakage current, ii) reactive power transfer capability, ii) utilizing minimum number of components compared to present five-level transformer-less inverters, iv) evenly distribution of voltage stress over the power switches, v) self-balancing capability of capacitor voltages, vi) reducing the size of capacitors, and vii) higher efficiency because of having only two switches being simultaneously turned on during each operation state. To achieve these advantages, a suitable switching scheme is introduced. Furthermore, the proposed circuit explanation, the optimal capacitor design process and features comparison with similar topologies are presented to illustrate the proficiency of the proposed 6S-5L CGT inverter. Moreover, a 500 VA experimental prototype is implemented to demonstrate the advantages of the proposed structure under different operating conditions for PV applications.