Open-circuit and Short-circuit Fault Diagnosis and Fault Tolerant Strategy for Non-isolated Three-level Boost DC-DC Converters for Photovoltaic Energies Applications

Abstract

Three Level Boost (TLB) DC-DC converters have been widely used in renewable energies, because of their advantages related to efficiency, volume, modularity, and inductor current ripples. To improve their reliability, a simple diagnosis method for switches Short-circuit (SC) and Open-circuit (OC) faults in a TLB converter and a fault-tolerant reconfiguration using only the output capacitor voltages sign features are presented. The capacitor voltages are thoroughly studied for both switches healthy and faulty modes. The presented method is robust, and no additional sensors are required. With the new approach, it's possible to locate the faulty switch, as well as determine if it's an OC or SC failure. As a result, the TLB converter is reconfigured to a conventional boost converter, ensuring service continuity by adding only a redundant switch as a remedy. The experimental results using the dSPACE DS1104 controller board validate the proposed diagnosis method.