Fault-Tolerant Control for a Modular Cascaded NPC Inverter Configuration

A modular, multi-port converter configuration realizes DC-AC conversion for a high-power grid-connected photovoltaic system; but one or more faults can occur in any of the highly numerous components. In this paper, a reconfigurable multi-port control is proposed to achieve fault detection and resolution among cascaded ports. A series of switching algorithms are applied, thus enabling a continued operation under faulty conditions. A detailed analysis and simulation results are presented for the control to detect the fault, localize it, and reconfigure the system for robust operation. The projected strategy is demonstrated using MATLAB/SIMULINK.