Wuhan University

Chunsong Sui

Yigang He

Hui Zhang

Mingyun Chen

Zhaorong Zeng

Bolun Du

A method and a system for diagnosing a fault of a three-phase three-level rectifier are relate to the technical field of fault diagnosis of power electronic equipment, and provided to implement identification and location of an open-circuit fault of a power switching device thereof. A deviation between an expected value and an actual value of a phase-to-phase voltage is adopted as a diagnosis variable. The diagnosis variable is calculated by adopting a screening technique, thereby reducing calculation error to ensure accuracy of diagnosis. Only existing voltage current signals in a control system of the rectifier are required to calculate the diagnosis variable, so no additional hardware is required and low-cost fault diagnosis can be implemented. Different voltage thresholds are adopted for different fault characteristic sections, and the voltage thresholds are updated in real time according to a direct current side voltage, which improves diagnosis speed while ensuring higher robustness.

Method and system for diagnosing open-circuit fault of power switching device of three-phase three-level rectifier

Provided are a failure diagnosis method and apparatus for open circuit failure of a power tube of a three-phase rectifier based on a current signal, relating to a failure diagnosis technique for power electronic equipment and capable of quickly and accurately diagnosing on an open circuit failure of the power tube of the three-phase rectifier without adding a hardware component. The failure diagnosis method only requires a sampled current existing in the control system of the rectifier and some intermediate computing signals and is therefore simple and requires little computing resource. A distorted current after the open circuit failure occurs in the power tube of the rectifier and a positive/negative half cycle where the current is present when the failure occurs serve as diagnostic variables. By analyzing the sampled current, a quick diagnosis on the power tube having the open circuit failure is provided. Thus, the invention is highly applicable.

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Hubei, China

Chunsong Sui