Sub-module fault diagnosis method of modular multilevel converter

A modular multi-level, fault diagnosis technology, applied in the field of power transmission and distribution, can solve problems such as undiagnosable fault diagnosis ability, complex hardware circuit design, etc.

CN103235219AInactive Publication Date: 2013-08-07NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2013-08-07
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a sub-module fault diagnosis method of a modular multilevel converter in the technical field of power transmission and distribution. According to the technical scheme, the method includes: firstly, performing fault feature analysis aiming at typical faults of sub-modules; secondly, configuring an SFDU (sub-module fault diagnosis unit) in an SMC (sub-module controller), and combining provided sub-module fault diagnosis indexes by the aid of capacitor voltage, bridge arm current and trigger signals at the moment so as to achieve diagnosis of faults of sub-module IGBT (insulated gate bipolar translator) short circuit, IGBT open circuit, FWD (freewheel diode) short circuit, capacitor failure and the like; and finally, adopting an exclusive method in a VBC (valve base controller) to achieve diagnosis of faults of sub-module FWD open circuit, capacitor open circuit failure, connection line open circuit and the like. The method has the advantages that diagnosis of sub-module faults is achieved on the base of software, additional measuring points are not added to an original control protection system, and the method is easy to implement, has quick and efficient sub-module fault diagnosis capability, and has coordination with other protection settings.
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Description

Technical field

[0001] The invention belongs to the technical field of power transmission and distribution, and in particular relates to a sub-module fault diagnosis method of a modular multilevel converter. Background technique

[0002] Modular Multilevel Converter (MMC) is a new voltage source converter topology proposed by R. Marquardt and A. Lesnicar in 2002. It does not require a large number of IGBTs in series, and the device withstands voltage change rate is low. The output waveform has lower harmonic content and other advantages. Therefore, the MMC-based high-voltage direct current transmission system (MMC-HVDC) is also a research hotspot in the field of direct current transmission in recent years.

[0003] At present, the sub-module (SM) widely used in the project adopts a half-bridge type sub-module structure, which is the basic unit that constitutes the MMC. The timely diagnosis and in-situ protection of fault conditions during operation directly affect the stable opera...

Examples

Embodiment Construction

[0054] The preferred embodiments are described in detail below in conjunction with the drawings. It should be emphasized that the following description is only exemplary, and is not intended to limit the scope and application of the present invention.

[0055] figure 1 The topological structure diagram of the modular multilevel converter MMC (half bridge) provided by the present invention. figure 1 Among them, SM1, SM2,..., SMn, represent the first submodule, the second submodule,..., the nth submodule in a bridge arm of MMC; L 0 Represents the bridge arm reactor; U dc Indicates the voltage difference between the positive and negative DC buses of the MMC. T1, T2 respectively represent the upper and lower IGBTs in the half-bridge submodule, D1, D2 respectively represent the anti-parallel diodes of the corresponding IGBTs; i arm Is the bridge arm current; C 0 Represents the capacitor in the half-bridge sub-module; U c Indicates the capacitor voltage of the sub-module; U SM Indi...