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Control method for accessing modular multilevel converter (MMC) station to DC power grid and controller

A control method and technology of DC power grid, applied in parallel operation of DC power supply, power transmission AC network, etc., can solve the problem of large inrush current, and achieve the effects of improving service life, smooth charging and reducing inrush current.

Active Publication Date: 2018-01-26
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of this, an embodiment of the present invention provides a control method and a controller for connecting an MMC converter station to a DC power grid, so as to solve the problem of excessive surge current generated when an MMC converter station is connected to a DC power grid

Method used

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  • Control method for accessing modular multilevel converter (MMC) station to DC power grid and controller
  • Control method for accessing modular multilevel converter (MMC) station to DC power grid and controller
  • Control method for accessing modular multilevel converter (MMC) station to DC power grid and controller

Examples

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Effect test

Embodiment 1

[0082] This embodiment provides a control method for connecting an MMC converter station to a DC power grid, which is used in a controller. Such as Figure 6 As shown, the control method includes the following steps:

[0083] Step S11, using the AC source of the MMC converter station to charge the first sub-module of the MMC converter station.

[0084] Such as Figure 5 As shown, in this embodiment, the MMC converter station includes an AC voltage source G1, which is electrically connected to the AC side of the MMC. Therefore, G1 can be used to charge the first sub-module of the MMC converter station, that is, G1 can be used to charge the first sub-module of the MMC converter station. The capacitor in the first sub-module of the MMC converter station is charged, so that the voltage of the capacitor in the first sub-module increases.

[0085] Step S12, judging whether the capacitor voltages of all the first sub-modules have increased to the rated operating voltage of the fir...

Embodiment 2

[0100] This embodiment provides a control method for connecting an MMC converter station to a DC power grid, which is used in a controller. Such as Figure 7 As shown, the control method includes the following steps:

[0101] Step S21, using the AC source of the MMC converter station to charge the first sub-module of the MMC converter station.

[0102] Specifically, step S21 specifically includes the following steps:

[0103] Step S211, perform blocking charging on all first sub-modules.

[0104] In this embodiment, the first sub-module of the MMC converter station is blocked and charged through the AC source of the MMC converter station, so that the capacitor voltage of the first sub-module is increased, that is, the voltage of the first sub-module is increased, and the MMC converter is further increased. The voltage on the DC side of the flow station.

[0105] Step S212, according to the locked charging state of the first sub-module, unlock and charge the first sub-modul...

Embodiment 3

[0120] This embodiment provides a control method for connecting an MMC converter station to a DC power grid, which is used in a controller. Such as Figure 8 As shown, the control method includes the following steps:

[0121] Step S30, initializing the MMC converter station and the DC / DC converter.

[0122] In this embodiment, the state of each submodule in the MMC converter station and the DC / DC converter is set to a locked state by the controller, and in addition, the DC circuit breaker in the circuit connecting the MMC converter station and the DC / DC converter The status of the inverter is set to closed, so as to ensure that the MMC converter station and the DC / DC converter are in an electrically connected state.

[0123] Step S31, using the AC source of the MMC converter station to charge the first sub-module of the MMC converter station.

[0124] Specifically, step S31 specifically includes the following steps:

[0125] In step S311, the first sub-module is charged by...

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Abstract

The invention discloses a control method for accessing a modular multilevel converter (MMC) station to a DC power grid and a controller. The method comprises the steps of charging a first sub-modularof the MMC station by an AC source of the MMC station; judging whether capacitance voltages of all first sub-modules are raised to rated working voltage or not; charging a DC / DC converter by the charged MMC station when a judgment result is yes; judging capacitance voltages of all sub-modules of the DC / DC converter are raised to the rated working voltage or not; and connecting a first DC side of the DC / DC converter and a DC power grid to be accessed when a judgment result is yes, and controlling a transmission power of the DC / DC converter so that the transmission power is raised to rated transmission power of the DC / DC converter. By ordered charging control of the MMC station and the DC / DC converter, employed by the embodiment of the invention, an impact current of the MMC station accessedto the DC power grid can be effectively reduced, so that the MMC station is easily and smoothly accessed to the DC power grid.

Description

technical field [0001] The invention relates to the technical field of flexible direct current transmission, in particular to a control method and a controller for connecting an MMC converter station to a direct current power grid. Background technique [0002] With the depletion of fossil energy and the weakening of environmental carrying capacity, renewable energy power generation has developed rapidly, such as wind power generation and solar power generation. These power generation devices have the characteristics of small installed capacity, relatively scattered distribution, and the principle of AC power grid. When connected to the AC main grid, due to the shortcomings of the traditional current source converter station, which can only work in the active inverter state and the short-circuit capacity of the converter station is small, it cannot meet the grid-connected requirements of these new energy sources. [0003] The voltage source converter station based on high-v...

Claims

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Application Information

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IPC IPC(8): H02J1/10H02J3/36
Inventor 吴亚楠杨杰李帅朱思丞韩乃峥
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
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