Self-Balanced Switched-Capacitor Common-Grounding Boost Multilevel Inverter

Abstract

Transformerless inverters have been extensively deployed in photovoltaic (PV) applications, owing to features such as high efficiency, high power quality, and low cost. However, the leakage current in such inverters due to the absence of galvanic isolation has resulted in several topological modifications. This paper introduces a single-input switched-capacitor (SC)-based multilevel inverter (MLI) that is capable of eliminating the leakage current due to its common-ground structure. Also, the proposed inverter has the capability of single-stage voltage boosting, which is essential in PV systems. The series–parallel switching facilitates the self-balancing of SCs, which, in turn, assists in voltage boosting. Moreover, the proposed MLI synthesizes a seven-level output using only eight switches. Following an in-depth analysis of the circuit operation, modulation scheme, and power losses, a detailed comparison among recently developed seven-level MLIs is carried out, which verifies the design's superiority. Extensive simulation and experimental results are presented to validate the prominent features of the seven-level MLI under dynamic operating conditions.