Robust Open-Circuit Fault Diagnosis of Multi-Phase Floating Interleaved DC–DC Boost Converter Based on Sliding Mode Observer

In this paper, a robust switch fault diagnosis method based on sliding mode observer is proposed and applied to the dc-dc multi-phase floating interleaved boost converter (FIBC). The proposed method requires only a crude converter model with nominal circuit parameters. It shows strong robustness to the circuit parameter uncertainties and disturbances. The diagnosis variables are already within the closed-loop control system, without needing extra sensors. The sampling requirement for fault diagnosis is the same level as that of the main controller. Therefore, the proposed diagnosis method can be added-on the available digital control system directly. The effectiveness and robustness of the proposed diagnosis method are validated by the simulation and experiment results. The switch open-circuit faults can be diagnosed in less than two switching periods.