Open-circuit fault diagnosis in interleaved DC-DC converters

Interleaved DC-DC converters have been widely applied, because of their benefits related to efficiency, size, thermal management, modularity and output current ripple cancellation. These converters present an enhanced fault tolerance capability, but an open-circuit fault can lead to ripple beyond load requirements. This paper presents a fault-diagnostic method for interleaved DC-DC converters using only the DC-link current derivative sign features. The DC-link current derivative is thoroughly studied for both healthy and faulty modes. Its sign variation during different time intervals defined by the number of switches in conduction mode contains important information for open-circuit fault detection. The presented method is robust to transients and current imbalance between phases and no additional sensors are required. A photovoltaic (PV) system application is presented to validate this method.