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Modular multilevel converter open-circuit fault diagnosis method based on Grubbs criterion

A modular multi-level, open-circuit fault technology, applied in the direction of instruments, measuring electricity, measuring electrical variables, etc., can solve the problems of prolonging the fault diagnosis time and complicating the fault diagnosis process, achieving extended time, easy implementation, and high efficiency. sticky effect

Active Publication Date: 2020-09-25
SOUTHEAST UNIV +2
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Problems solved by technology

All these methods need to perform fault detection and fault localization separately, which not only complicates the fault diagnosis process, but also prolongs the time required for fault diagnosis

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  • Modular multilevel converter open-circuit fault diagnosis method based on Grubbs criterion
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  • Modular multilevel converter open-circuit fault diagnosis method based on Grubbs criterion

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Embodiment Construction

[0034] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0035] Aiming at the problem of open-circuit faults in sub-modules, the present invention proposes a sub-module fault diagnosis method suitable for MMC, wherein the MMC topology is composed of six bridge arms, such as figure 1 As shown, each bridge arm contains N identical submodules (Submodule, SM) and a bridge arm inductance L s , the sub-module adopts a half-bridge structure, and each sub-module consists of two power switches S u , S l , two diodes D u 、D l and a DC capacitor C. Among them, the power switch S u and diode D u Composition of the upper tube, the power switch S l and diode D l Form the downtube. Diode D u The cathode connection of the power switch S u the collector of the diode D u The anode connection of the power switch S u the emitter of the diode D l The cathode connection of the power switch S l the colle...

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Abstract

The invention discloses a modular multilevel converter open-circuit fault diagnosis method based on the Grubbs criterion. The method comprises the steps of: providing a quantitative index CVV value based on capacitor voltage change; calculating CVV values of all the sub-modules and sorting the CVV values according to an ascending order; calculating the average value and the standard deviation, respectively calculating the deviation between the average value and the CVV maximum value and the deviation between the average value and the CVV minimum value, marking the submodule with the maximum deviation as a suspicious submodule, calculating the Grubbs value of the suspicious submodule, judging whether the suspicious submodule reaches the fault standard or not, and achieving the fault detection and positioning at the same time. The invention only relates to the capacitor voltage of the sub-module, and does not need additional hardware resources. According to the invention, the occurrenceof single and multiple faults can be correctly handled. The method does not relate to system parameters, does not need to construct a system mathematical model, is not affected by parameter uncertainty, and has very high robustness.

Description

technical field [0001] The invention belongs to the technical field of multilevel power electronic converters. Background technique [0002] Compared with traditional two-level and three-level converters, modular multilevel converters (ModularMultilevelConverter, MMC) have the characteristics of high efficiency, small output AC voltage harmonics, and high modularity, and are more suitable for high voltage, For high-power applications, it has broad application prospects in flexible DC transmission, medium-voltage motor drives and other fields. [0003] By dividing the bulk DC capacitance into smaller capacitors, series-connected sub-modules (SM) can be implemented in MMCs. This unique structure results in no large-capacity DC capacitors, lower switching synchronization requirements and a higher degree of modularity. However, a large number of series-connected submodules poses a huge threat to MMC reliability because they become huge potential points of failure. [0004] Th...

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Application Information

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IPC IPC(8): G01R31/54G01R31/56G06F17/18
CPCG06F17/18G01R31/54G01R31/56
Inventor 邓富金金铭张建忠王青松窦晓波吴在军陈舒
Owner SOUTHEAST UNIV