In stand-alone power supply including a fuel cell (FC) and photovoltaic panels, DC/DC converters must meet several requirements from compactness, high voltage ratio, input current ripples reduction, high energy efficiency and reliability regarding keeping its function in case of power switch failures point of view. In this paper, a floating interleaved DC/DC boost converter has been chosen in order to meet the requirements for FC and photovoltaic applications. Despite the presence of a natural redundancy, a power switch failure may drastically reduce the reliability of the converter due to the additional stress on the electrical components. The purpose of this paper is to propose a power switch fault detection method based on Park's vector and a management of operating degraded mode. Obtained simulation and experimental results allow demonstrating the performance of the developed fault detection method to enhance the overall reliability of the converter.