Modular multilevel converter (MMC) circulating current suppression method

A modular multi-level, circulating current suppression technology, applied in the direction of converting AC power input to DC power output, irreversible DC power input to AC power output, electrical components, etc., can solve the incompatibility of single-phase and three-phase The system and control method are complicated, and the circulation suppression ability is poor, so as to reduce the circulation current, improve the circulation suppression ability, and reduce the switching loss.

Inactive Publication Date: 2013-10-02
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In order to solve the problem that the existing multi-level converter circulation suppression method cannot be compatible with single-phase and three-phase sy

Method used

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  • Modular multilevel converter (MMC) circulating current suppression method
  • Modular multilevel converter (MMC) circulating current suppression method
  • Modular multilevel converter (MMC) circulating current suppression method

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specific Embodiment approach 1

[0038] Specific implementation mode one: combine figure 1 , figure 2 , image 3 , Figure 4 Describe this embodiment, the method for suppressing the circulating current of a modular multilevel converter described in this embodiment is realized based on a modular multilevel converter, and the modular multilevel converter based on three Each phase circuit is composed of upper and lower bridge arm inductors and n sub-modules in series, where 1≤n<+∞, each sub-module is composed of a half-bridge converter and an energy storage capacitor 1-1, The half bridge converter includes No. 1 diode 1-2, No. 1 controllable switch 1-3, No. 2 controllable switch 1-4 and No. 2 diode 1-5; the cathode of No. 1 diode 1-2 is connected to No. 1 The collector of the controllable switch 1-3 and one end of the energy storage capacitor 1-1; the emitter of the first controllable switch 1-3, the collector of the second controllable switch 1-4 and the second diode 1-5 The cathodes are connected, and the...

specific Embodiment approach 2

[0058] Embodiment 2: This embodiment is a further description of the method for suppressing the circulating current of a modular multilevel converter described in Embodiment 1. The notch filter described in step 71 adopts an infinite impulse response digital filter. The transfer function of the digital filter is:

[0059] N ( s ) = s 2 + ω 0 2 s 2 + 2 τ 0 ω 0 + ω 0 2 - - - ( 1 )

[0060] where ω 0 is the...

specific Embodiment approach 3

[0065] Embodiment 3: This embodiment is a further description of the method for suppressing the circulating current of a modular multilevel converter described in Embodiment 1. The transfer function of the proportional resonance controller is: The transfer function of the proportional resonance controller is:

[0066] F PR _ quasi ( s ) = K p + 2 K r s s 2 + 2 ω c s + ω 0 2 - - - ( 3 ...

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Abstract

A modular multilevel converter (MMC) circulating current suppression method is provided. The invention belongs to the technical field of electrical engineering, specifically relates to a suppression method for suppressing internal circulating current of an MMC, and solves problems of incompatibility with single phase and three phase systems, poor circulating current suppression capability and a complicated control method in conventional MMC circulating current suppression methods. According to the MMC circulating current suppression method, a wave trap is used for acquiring secondary harmonic signals in phase current; the harmonic signals in the phase current are subtracted from the average current of the phase current so that average current signals of an upper bridge arm and a lower bridge arm in which secondary harmonic waves are subtracted are acquired; the average current signals of an upper bridge arm and a lower bridge arm in which secondary harmonic waves are subtracted is taken to do subtraction with a reference current, and thus secondary harmonic signals of the circulating current is acquired; a proportional resonant controller is used for performing current tracing on the secondary harmonic waves of the circulating current, and thus voltage compensation signals are acquired; the compensation signals are processed and then are given back to sub-modules of the upper bridge arm of the MMC, and thus circulating current suppression is realized. The MMC circulating current suppression method is suitable for the technical field of electrical engineering.

Description

technical field [0001] The invention belongs to the field of electrotechnical technology, and in particular relates to a suppression method for suppressing internal circulation of a modular multilevel converter. Background technique [0002] With the increasing number of new energy supply channels, Voltage Sourced Converter Based HVDC (VSC-HVDC) technology has attracted more and more attention. The traditional two-level or three-level VSC topology has problems such as high switching loss, high current harmonics, and low reliability. Compared with other converters, the modular multilevel converter (MMC) proposed by German scholar Rainer Marquardt has advantages such as redundant control, more output levels, and common DC Advantages such as bus bars provide a new solution for high-voltage and high-power energy conversion applications. However, due to the large number of modules in the modular multilevel converter, there are technical obstacles such as complex control strateg...

Claims

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Application Information

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IPC IPC(8): H02M7/49
CPCH02M7/4835
Inventor 申科班明飞赵丹
Owner HARBIN INST OF TECH
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