A Novel Fault Tolerant Full Bridge DC/DC Converter for Photovoltaic application

Abstract: Power switches in converters are prone to open and short circuit faults. Faulty power switch in converters worsens the converter performance and it may result in failure of other devices also. Further when main power switch fails, it results in breakdown of entire system. Therefore for reliability improvement of full bridge DC/DC converter in PV system, this research paper presents a novel fault tolerant converter topology for exact faulty power switch localization and isolation from main path so that redundant faulty power switch can be brought in action and still system will provide desired output power. The converter presented here need two redundant power switches and relays to provide fault tolerant competence. It has four operating states which are normal state, faulty state, fault diagnostic state and fault recovery state. In the technique presented here RMS current at given test points is computed and compared with threshold RMS current for determination of faulty power switch. Graph theory is used to show the topological equivalence of converter in normal and fault recovery states. Simulation and experimental results have shown that converter efficiency remains same in both normal and fault recovery state