Five-Level Grid-Tied Inverter Employing Switched-Capacitor Cell with Common-Grounded Feature

An advanced topology of single-phase five-level transformerless grid-connected inverter is presented in this paper, which offers a common ground between the input source and the null of the grid. This alleviated the concern of variable common-mode voltage and the leakage current problem, which makes the inverter suitable for grid-tied photovoltaic (PV)-based applications. The proposed topology is operated by a series-parallel switching conversion of a switched-capacitor (SC) cell. It consists of a single dc source, two power diodes/capacitors alongside six power switches. Using the SC technique, a single-stage two times voltage boosting inverter with a self-voltage balancing of the capacitors is achieved. By employing the SC cell, five distinct voltage levels are also made at the inverter's output, so a small L-Type filter can be utilized. The control/modulation of the proposed inverter is also on the basis of a new peak current controller (PCC) technique. The circuit description along with the proposed PCC operation is discussed and a brief comparative study besides the experimental results are given at the end to demonstrate the feasibility of the proposed topology.