Evaluation and fault tolerant control of a floating interleaved boost converter for fuel cell systems

Due to the relatively low and unregulated output voltage of fuel cell (FC) stack, a dc-dc floating interleaved boost converter (FIBC) is used to interface FC stack and dc bus in FC systems. In order to keep a constant dc bus voltage of FC systems even when power switch open-circuit fault (OCF) occurs, the small signal ac model and proper control scheme for FIBC are well developed. Thus, when switch OCF occurs in one module, the FIBC switches from normal mode into degraded mode (constant output voltage is guaranteed) automatically. While, the evaluation results of FIBC in degraded mode indicate that the components such as power switch, capacitor and inductor should be oversized significantly. Therefore, a fault tolerant control scheme is designed alternatively. Finally, the validity of analytical evaluation results and the FTC scheme are demonstrated by Matlab/Simulink simulations.