A Fault Tolerant Multilevel Inverter for Off-grid Solar Photovoltaic Application

Multilevel inverters (MLIs) provide a number of advantages including, modularity, higher efficiency, lower dv/dt stress, and minimal filtering requirements. The number of switching devices and the complexity of control will increase with increasing voltage levels in the conventional MLI. As a result of the higher number of switching devices, there may be an increased chance of failure, which compromises the MLI’s reliability. The goal of current research trends is to increase the reliability of MLIs by using an optimal number of switching devices. It is important to ensure fault tolerance in many industrial applications where continuity of power supply is a key requirement. The fault tolerant (FT) operation of an MLI has, therefore, been the subject of considerable research. This paper proposes a new topology with FT capabilities for solar photovoltaic (PV) application that enhances the reliability of MLIs. The topology has the ability to generate 7-level, and (9-level and 11-level) in normal condition at the output using symmetric and asymmetric source configurations, respectively. Based on simulation results performed within the MATLAB/Simulink environment, the feasibility of the proposed FT MLI is demonstrated for different switch faults.