Common-Ground-Type Quadruple Boosting Nine-Level Inverter

Abstract

Transformerless multilevel inverters with boosting features are widely used in residential and commercial photovoltaic applications due to their advantages, such as compact size, low cost, high voltage gain, and higher efficiency. However, they suffer from ground leakage current, which degrades power quality and poses safety issues. In this article, a nine-level quadruple-boost inverter with common ground is proposed using the concept of switched capacitor (SC). Due to the common ground, the proposed topology eliminates the leakage current. The voltages of SC are self-balancing without the need for external dedicated circuits or sensors. The operating principle of the proposed topology is described in detail, followed by the design guidelines for sizing SC. The comparative summary highlights the advantageous features of the proposed topology, including fewer components, high gain, self-balancing capability of SCs, lower conduction and switching losses, and near-zero leakage current. In addition, through a detailed volume and cost-based comparison, it will be shown that the proposed topology has the lowest volume (278.95 cm $^{3}$ ) and cost (114.81 $) amongst its counterparts. Further, the performance of the proposed topology is validated through several experiments on a 1 kW laboratory prototype, and the results are presented for grid-connected and stand-alone modes.