Method and system for calculating alternating current asymmetric fault main loop of modular multilevel converter

A modular multi-level and calculation method technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve problems that cannot cover modular multi-level converters, etc.

Active Publication Date: 2019-04-09
STATE GRID CHONGQING ELECTRIC POWER CO ELECTRIC POWER RES INST +3
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Problems solved by technology

This method is more detailed in the analytical analysis of the AC part of the electrical quantity of the modular multilevel converter in the fault state, and the analytical analysis of the DC part is also relatively concise, but it still cannot cover all important internal components of the modular multilevel converter. Calculation of electrical quantity

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  • Method and system for calculating alternating current asymmetric fault main loop of modular multilevel converter
  • Method and system for calculating alternating current asymmetric fault main loop of modular multilevel converter
  • Method and system for calculating alternating current asymmetric fault main loop of modular multilevel converter

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Embodiment Construction

[0052] The present invention will be further described below in conjunction with drawings and embodiments.

[0053] Examples such as figure 1 Shown; a calculation method for the AC asymmetric fault main circuit of a modular multilevel converter, and the calculation formula of the main electrical quantity change of the modular multilevel converter generated by the negative sequence current of the fault is given, Including sub-module capacitance current variation, sub-module capacitance fluctuation voltage variation, circulating current variation, DC voltage variation and DC current variation, the calculation process is as follows:

[0054] 1) Sub-module capacitive current variation

[0055] The capacitive current is the product of the coupling effect of the bridge arm current and the switching process of the sub-module. The capacitive current variation caused by the negative sequence fault current should be the product of the switching function and the negative sequence compo...

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Abstract

The present invention discloses a method and system for calculating an alternating current asymmetric fault main loop of a modular multilevel converter. The method comprises: the modular multilevel converter is connected with an alternating current system to generate a fault negative sequence current; and amount of electrical quantity change in the modular multilevel converter is calculated according to the fault negative sequence current. The method is based on the electrical quantity cyclic coupling relationship of the modular multilevel converter, and introduces the negative sequence faultcurrent into the internal cyclic coupling relationship of the modular multilevel converter to reflect influence of the asymmetric fault, and gives an analytical expression of the main electrical quantity inside the modular multilevel converter under an asymmetrical alternating current fault state, and can intuitively reflect the influence of the asymmetric alternating current fault on the modularmultilevel converter.

Description

technical field [0001] The invention relates to the technical field of high-voltage and large-capacity power electronic converters, in particular to a calculation method and system for an AC asymmetric fault main circuit of a modular multilevel converter. Background technique [0002] Modular multilevel converter is a voltage source power electronic converter, based on fully controlled power electronic devices such as insulated gate bipolar transistors and pulse width modulation technology, it can stably control active power and reactive power in AC and DC transfer between systems. The modular multilevel converter includes three phase units a, b, and c, and each phase unit includes two bridge arms, that is, an upper bridge arm and a lower bridge arm, for a total of six bridge arms. The three phase units are connected in parallel between the DC positive pole and the DC negative pole, and the middle points of the upper bridge arm and the lower bridge arm of the three phase un...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/483H02M1/32
CPCH02M1/32H02M7/483H02M1/325
Inventor 蒋望李笑倩李亚军魏应冬徐瑞林陈涛朱小军朱晟毅向红吉赵科马兴
Owner STATE GRID CHONGQING ELECTRIC POWER CO ELECTRIC POWER RES INST
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