Abstract
The paper presents a five-level common ground type (5L-CGT), transformer-less inverter topology with double voltage boosting. The proposed inverter uses eight switches and two capacitors, charged at input voltage level. The inverter in its basic form acts as a string inverter for low-power PV applications. However, it can be extended to work as a scalable multi-level inverter with higher power handling capability to act as a centralized inverter. The working of the inverter with the sizing of the components is presented with mathematical analysis. The efficiency of the proposed PV inverter is found using thermal losses associated with switches using PLECS software. A prototype of 1 kW has been designed, and experimentation has been carried out. Various loads with a lagging power factor up to 0.6 have been tested with the inverter to establish the usability of the proposed inverter in a worst-case emulated home-use scenario. The total harmonic distortion (THD) at the output has been recorded using a power quality analyzer with voltage and current THD values of 4.5% and 2.5%, respectively, which lies within the limits of IEEE 519 standards. The highest power conversion efficiency of the inverter has been recorded to be 96.20%.