A Robust Open-Circuit Fault Diagnosis Method for Three-Phase Interleaved Boost Converter

An open-circuit fault will increase input current ripple and reduce the energy transmission efficiency, which will deteriorate the inherent advantages of an interleaved boost converter. To guarantee the efficient and reliable operation of a system, it is necessary to diagnose the open-circuit fault by sensing the input current. In practical application, the sampling value of the input current will be polluted by noise and disturbance, which will weaken the robustness of fault diagnosis. To address the problem, this article proposes a robust open-circuit fault diagnosis method. By theoretically deriving the input current, it can be found that the input current contains helpful information, which can be used to identify the fault phase. The proposed method extracts this useful information by sampling the input current and holding it at specific moments. Moreover, this method integrates the sampling values to enhance robustness against noise. The fault phase can quickly be detected and located by observing and comparing the integrals during two switching periods. The method has robustness against the noise and the disturbance. Additionally, the method needs no extra sensors to sense the input current, which the control loop uses. Simulations and hardware experiments are carried to prove the practicability and the robustness of the proposed method.