Differential flatness control method of MMC-HVDC for supplying power to passive network under asymmetric fault

A MMC-HVDC, differential flat technology, applied in AC network circuits, geometric CAD, power transmission AC networks, etc., can solve problems such as difficulty in detecting output current
CN111969643APending Publication Date: 2020-11-20SHANGHAI UNIVERSITY OF ELECTRIC POWER
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
SHANGHAI UNIVERSITY OF ELECTRIC POWER
Publication Date
2020-11-20

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Abstract

The invention relates to a differential flatness control method of MMC-HVDC for supplying power to a passive network under an asymmetric fault. The method comprises the following steps: 1) analyzing astructure and a working principle of an MMC-HVDC system for supplying power to the passive network; 2) establishing a mathematical model based on a positive and negative sequence system for the MMC converter of the HVDC rectifier stage when the power grid voltage is unbalanced; 3) taking the output variables as active power and reactive power, and analyzing the stability of the MMC system; and 4)designing the positive and negative sequence control of the inner and outer rings of the MMC-HVDC converter station according to the differential flatness theory. The method provided by the inventionis suitable for the conditions of normal operation of a power grid and a power grid voltage fault, is quick in dynamic response, is wide in application range, can solve problems that the detection precision of an output current is not enough and the dynamic performance of an MMC converter becomes poor when an asymmetric fault happens to the power grid, and effectively improves the stability of anMMC-HVDC system.
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Description

technical field

[0001] The invention relates to the technical field of MMC-HVDC control, in particular to a differential flattening control method for MMC-HVDC supplying power to a passive network under asymmetric faults. Background technique

[0002] Modular Multilevel Converter (MMC) has attracted extensive attention as a power converter topology used in high power and high voltage systems. Due to its advantages such as small output harmonics, low power loss and modularity, it has become the first choice for high-voltage direct current (HVDC) system converters.

[0003] However, when the HVDC system operates normally, it is likely to encounter faults such as phase-to-ground or voltage sag of the three-phase power grid, which seriously affects the stability and security of the power system. With the rapid development of the power system and the construction of the ubiquitous power Internet of Things, higher requirements have been placed on the transmission capacity and sta...

Claims

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