Capacitor multiplexing type modular multilevel converter and control method thereof

A modular multi-level converter technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve complex control strategies, and is not suitable for multiple methods to be used together, etc. problems, to achieve high operational reliability, save the number of capacitor assemblies, and reduce the effect of unbalance and fluctuation

Active Publication Date: 2022-05-27
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, some new topologies have their own parameter design or complex control strategies, which are not suitable for the use of multiple methods

Method used

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  • Capacitor multiplexing type modular multilevel converter and control method thereof
  • Capacitor multiplexing type modular multilevel converter and control method thereof
  • Capacitor multiplexing type modular multilevel converter and control method thereof

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Embodiment 1

[0061] The modular multilevel converter MMC has a three-phase topology, and each phase has the same topology, including three phase units with the same structure, namely A-phase unit, B-phase unit and C-phase unit. The unit includes an upper bridge arm and a lower bridge arm, so the three-phase converter has a total of 6 bridge arms, and each bridge arm includes N sub-modules, so each phase includes 2N capacitors. During normal operation, N capacitors are in charge and discharge state at every moment, and the remaining N capacitors are in the cutoff state, and the capacitor utilization rate is low, only 50%. Therefore, in order to improve the utilization rate of capacitors and reduce the number of capacitor assemblies, this embodiment proposes a capacitor multiplexing type modular multilevel converter, so that each phase has one sub-module on the upper bridge arm and one sub-module corresponding to the lower bridge arm. Sharing the same capacitor, on the premise of ensuring hi...

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PUM

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Abstract

The invention discloses a capacitor multiplexing type modular multilevel converter and a control method thereof, and relates to the technical field of power supply power systems. The capacitor multiplexing type modular multilevel converter comprises an upper bridge arm, a lower bridge arm and a multiplexing capacitor; each of the upper bridge arm and the lower bridge arm comprises a plurality of cascaded sub-modules, a direct current side port of any sub-module of the upper bridge arm is connected in parallel with a direct current side port of the corresponding sub-module in the lower bridge arm, and the direct current side port of any sub-module of the upper bridge arm and the direct current side port of the corresponding sub-module in the lower bridge arm are connected in parallel with the same multiplexing capacitor; the working states of the two sub-modules sharing the multiplexing capacitor are opposite; one sub-module of each phase of upper bridge arm and one corresponding sub-module of each phase of lower bridge arm share the same capacitor, so that on the premise of ensuring high operation reliability and simple control strategy, the assembling number of the capacitors is reduced, and the weight, volume and occupied area of the converter station are reduced.

Description

technical field [0001] The invention relates to the technical field of power supply systems, in particular to a capacitor multiplexing type modular multilevel converter and a control method thereof. Background technique [0002] Modular multilevel converter (MMC) is composed of multiple sub-modules (Sub-module, SM) cascaded with the same structure. MMC has high voltage quality, high scalability, low harmonic content and control It has many advantages such as flexibility and is widely used in many flexible DC projects. [0003] Compared with the traditional two-level and three-level converters that have large capacitors in parallel on the DC side, MMC is equipped with a large number of capacitors distributed in the sub-modules. The huge number of sub-modules of MMC can increase the number of output levels and make the output voltage ladder wave approach a sine wave, but the disadvantage is that it needs to assemble a large number of power switching devices and capacitors. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/00H02M7/483H02M7/5387H02M1/14
CPCH02M7/00H02M7/483H02M7/53871H02M1/14Y02E60/60
Inventor 王毅余祖泳王琛魏子文张振余欣洋
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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