Fault Tolerant Strategy for a Photovoltaic DC-DC Converter

The photovoltaic technology has a small impact on the environment and is suitable for a wide range of applications. The main barrier for a more extensive implementation has been the reliability, mainly related to the power converters. According to this consideration, this paper presents an open-circuit fault diagnosis and fault-tolerant scheme for a three-level boost converter in a photovoltaic power system using batteries as storage devices. The fault diagnostic method takes advantage only of the control variables used for maximum power point tracking and output dc link capacitor voltage balance. The fault-tolerant strategy requires only a few components added to the original threelevel boost converter, so that, under an open-circuit power switch fault, it can be partly reconfigured into a two-level boost converter ensuring battery energy supply. Experimental results verify the proposed fault diagnostic method and reconfiguration for fault-tolerant operation.