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A control method and system for a modular multilevel converter

A modular multi-level and control 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 such as stability and insufficient fault transient recovery characteristics

Active Publication Date: 2021-04-30
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing MMC circuits based on constant voltage and constant frequency control, which have insufficient stability and fault transient recovery characteristics, thereby providing a modular multi-level converter Flow control method and system

Method used

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  • A control method and system for a modular multilevel converter
  • A control method and system for a modular multilevel converter
  • A control method and system for a modular multilevel converter

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Embodiment 1

[0038] An embodiment of the present invention provides a control method for a modular multilevel converter, which is applied in the field of power electronic control of a power system, such as figure 1 As shown, the MMC connected to the three-phase grid on the AC side includes six bridge arms, each bridge arm contains multiple sub-modules, and each bridge arm controls the output voltage of the bridge arm by controlling the number of input sub-modules, so the figure 1 The shown MMC circuit structure is simplified as figure 2 The MMC circuit structure shown. exist figure 2 In , all sub-modules on each bridge arm are regarded as controlled voltage sources, and 10 nodes are set.

[0039] Such as image 3 As shown, the control method of the modular multilevel converter provided by the embodiment of the present invention includes:

[0040] Step S1: Obtain the instantaneous parameters of the state quantities of the modular multilevel converter and the reference parameters of th...

Embodiment 2

[0091] An embodiment of the present invention provides a control system for a modular multilevel converter, such as Figure 14 shown, including:

[0092] The parameter acquisition module 1 is used to acquire the instantaneous parameters of the state quantities of the modular multilevel converter and the reference parameters of the preset state quantities; this module executes the method described in step S1 in Embodiment 1, which will not be repeated here.

[0093] The DC side constant current control module 2 is used to control the DC side of the modular multilevel converter with a constant current by using the instantaneous parameters of the state quantity and the preset state quantity reference parameters to obtain the instantaneous reference voltage of the first DC side node and The instantaneous reference voltage of the second DC side node; this module executes the method described in step S2 in Embodiment 1, which will not be repeated here.

[0094] The constant voltage...

Embodiment 3

[0099] An embodiment of the present invention provides a controller, such as Figure 15 As shown, it includes: at least one processor 401 , such as a CPU (Central Processing Unit, central processing unit), at least one communication interface 403 , memory 404 , and at least one communication bus 402 . Wherein, the communication bus 402 is used to realize connection and communication between these components. Wherein, the communication interface 403 may include a display screen (Display) and a keyboard (Keyboard), and the optional communication interface 403 may also include a standard wired interface and a wireless interface. The memory 404 may be a high-speed RAM memory (Ramdom Access Memory, volatile random access memory), or a non-volatile memory (non-volatile memory), such as at least one disk memory. Optionally, the memory 404 may also be at least one storage device located away from the aforementioned processor 401 . The processor 401 can execute the control method of ...

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Abstract

The invention discloses a control method and system for a modularized multilevel converter. The method includes: controlling the constant current on the DC side to obtain the instantaneous reference voltage of the first DC side node and the instantaneous reference voltage of the second DC side node; By tracking the flux linkage of each bridge arm node, the constant voltage and constant frequency control is performed on the AC side to obtain the instantaneous reference node voltage of each bridge arm; the instantaneous reference voltage of the first DC side node and the second DC side node instantaneous Reference voltage and the instantaneous reference node voltage of each bridge arm to obtain the reference voltage of each bridge arm; according to the reference voltage of each bridge arm, use the preset modulation method to determine the input sub-module of each bridge arm to generate a modular multi- Level shifter trigger signal. The invention converts the control of the DC side current into the control of the node voltage by controlling the constant current of the DC side, and realizes the control of the node voltage by tracking the node flux linkage, thereby improving the stability of the converter and the recovery of fault transients characteristic.

Description

technical field [0001] The invention relates to the field of power electronics technology and power system control, in particular to a control method and system for a modular multilevel converter. Background technique [0002] Modular Multilevel Converter (MMC) has flexible control, strong scalability, low harmonic order, no commutation voltage, and can independently adjust active power and reactive power at the same time. A little bit, which makes it have a broad application prospect in the HVDC neighborhood of passive network power supply. When the MMC supplies power to the passive network, it is often necessary for the MMC to provide a stable AC voltage. At this time, it is necessary to control the MMC at a constant voltage and constant frequency; in addition, in a wind farm that needs to transmit power through the MMC flexible DC transmission, because the fan is often for To achieve maximum power tracking, MMC is required to provide AC voltage with stable frequency and ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/483H02M1/32H02M7/5387H02M1/12
CPCH02M1/12H02M1/32H02M7/483H02M7/53871H02M1/0038H02M7/4835
Inventor 纪锋胡祥楠高路谷怀广刘栋林畅
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD