Common Ground-Based Fault-Tolerant Multi-Level Inverter With Boosting Capabilities for Photovoltaic Application

In recent years, Common-Ground-Transformerless (CGT) inverters have gained popularity as a cost-effective and compact alternative for grid-connected photovoltaic (PV) systems, offering significant characteristics such as voltage boosting ability, multi-level output voltage capability, and neutralization of leakage current. However, addressing the fault-tolerant (FT) mechanism under multiple switch failures of these CGT multilevel inverters (MLIs) with the preservation of output power post-fault is limited to lower voltage levels. This paper proposes an FT-CGT seven-level (7L) inverter with inherent boosting capabilities for a solar-powered grid-connected system. Counterparts to other recent CGT inverter topologies, this suggests a novel FT topology with only two self-balanced switched capacitors and the least device count to preserve the output power under multiple open circuit (OC) faults. Moreover, the topology can generate variation in output voltage levels and load current under different modulation indices, dynamic load conditions, frequency variation, and harmonic variation. In addition, a detailed Markov reliability assessment is performed to prove the superiority of the stated FT architecture. Unlike the other competent 7L-FT inverters, the cost quotation requirement is lower. Finally, the suggested topology is validated efficiently and effectively under a laboratory hardware setup.