MMC fault current suppression method based on model predictive control algorithm

A model predictive control and fault current technology, applied in power transmission AC networks, electrical components, circuit devices, etc., can solve the problems of switching device blocking, large amount of calculation, damage, etc., to achieve short-circuit current suppression, simple control structure, calculation Effects with low ability requirements

Active Publication Date: 2020-12-15
POWERCHINA HUADONG ENG COPORATION LTD
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Problems solved by technology

This simplified method greatly optimizes the calculation efficiency of the MMC model predictive control strategy. However, since this method does not consider the fault current suppression method of the MMC under the grid fault, when the grid fault occurs, the switching device may be blocked due to overcurrent or damage, seriously affecting the safe operation of the system
In addition, this method realizes the control of the system in the three-phase coordinate system, and the calculation amount in the control process is still relatively large

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  • MMC fault current suppression method based on model predictive control algorithm
  • MMC fault current suppression method based on model predictive control algorithm
  • MMC fault current suppression method based on model predictive control algorithm

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[0034] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] With reference to accompanying drawing, the system realization of the MMC fault current suppression method based on model predictive control algorithm among the present invention is as figure 2 As shown, the system includes a voltage sensor 1, a current sensor 2, a Clark transformation module 3, a Park transformation module 4, a grid voltage controller 5, a Park inverse transformation module 6, an output current prediction module 7, an output current objective function calculation module 8, and a bridge Arm energy prediction module 9, bridge arm energy objective function calculation module 10, internal circulation prediction module 11, internal circulation objective function calculation module 12, weight factor calculation module 13, final objectiv...

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Abstract

The invention discloses an MMC fault current suppression method based on a model prediction control algorithm, and formulates a prediction algorithm and an objective function of output current, bridgearm energy and internal circulation of an MMC model prediction control strategy in order to solve the problem that the fault current of the alternating current side of an MMC converter station is toolarge when an alternating current power grid fails. And by adjusting the weight factor of the output current in the target function, the short-circuit current on the alternating-current side when a fault occurs is effectively suppressed. Compared with an existing MMC model prediction control strategy, the method has the advantages that steady-state control and fault current suppression of the system are achieved under a two-phase static [alpha]-[beta] coordinate system, and safe and stable operation of the flexible direct-current power transmission system is guaranteed. The MMC fault currentsuppression method based on the model predictive control algorithm is simple in structure and remarkable in effect, and has high engineering practical value.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to an MMC fault current suppression method based on a model predictive control algorithm. Background technique [0002] The flexible DC transmission technology based on the modular multilevel converter (MMC) topology adopts the sub-module cascading method instead of the direct series connection of switching devices, which has the advantages of low manufacturing difficulty, low switching loss, and high waveform quality. , and thus has been widely used. However, when the AC grid fails, the HVDC system will also be severely affected. Taking the offshore wind power direct transmission system as an example, when a short-circuit fault occurs in the offshore AC grid, the DC system provides a large short-circuit current through the MMC, and the power electronic devices in the MMC are limited in their ability to withstand overcurrent. Effective measures, short-circuit...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36H02J3/00H02M7/483
CPCH02J3/36H02J3/001H02M7/483H02M7/4835Y02E60/60
Inventor 王霄鹤周才全陈晴杨文斌谢瑞杨林刚傅春翔李景一徐志辉高玉青
Owner POWERCHINA HUADONG ENG COPORATION LTD
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