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Modular multilevel converter level number multiplication method and starting method

A modular multi-level, inverter 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 complex control

Active Publication Date: 2014-09-24
XJ ELECTRIC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to provide a kind of, in order to solve the prior art needs to improve by means of hardware, the problem of complex control

Method used

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  • Modular multilevel converter level number multiplication method and starting method
  • Modular multilevel converter level number multiplication method and starting method
  • Modular multilevel converter level number multiplication method and starting method

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Embodiment 1

[0028] As an embodiment of the present invention, such as figure 1 For the half-bridge sub-module multi-level converter, when redundant control is not considered, the present invention only needs to control the three sub-modules at half of the rated voltage of the full-voltage sub-module, thereby relying on outputting half of the sub-module voltage to achieve level Number doubling effect.

[0029] Due to the presence of a certain DC component in the bridge arm current, the amount of electricity charged and discharged for the half-voltage sub-module is different during the positive and negative half cycles of the current. When the system works at a no-load modulation degree of 0.85, and the system operates under the worst working condition of rated active power and zero reactive power, the ratio of the bridge arm current to the charging and discharging power of a single sub-module will reach more than 4 times. In the voltage equalization control of the half-voltage sub-modules...

Embodiment 2

[0047] Such as image 3 Shown is the control block diagram of the redundant system, due to the need to apply redundant design to increase system reliability. The redundant control of the full voltage sub-module has been applied in the traditional method, and the present invention only analyzes the redundant control method of the half-voltage sub-module.

[0048] The control method is basically the same as in Embodiment 1, the difference is that the number of half-voltage sub-modules is M, more than 3, of which 3 are controlled according to the method of the embodiment, and M-3 are used as redundant half-voltage modules.

[0049] Use the redundant half-voltage module together with the working half-voltage module for control, voltage equalization, redundant method (see image 3 ) is improved on the basis of the above method, and only the improved part is described below.

[0050] The redundant half-voltage module participates in the overall voltage equalization control of the ...

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Abstract

The invention relates to a modular multilevel converter level number multiplication method and a starting method. According to the control method, when redundancy control is not considered, what a user needs to do is to control at least three sub-modules of each bridge arm to be one half of a rated module capacitor voltage (module voltage for short), so that the level number double effect can be realized by outputting output one half of the sub-module voltages. The half-voltage sub-module (HVSM) set participates in the voltage balancing control of full-voltage sub-modules (FVSM), and at the same time, voltage balancing is performed in the half-voltage sub-modules to maintain the voltage stability of the two kinds of sub-modules. The method is easy to implement, the topology and the modulation strategy do not need to be changed, and the control and the voltage balancing effect of the full-voltage sub-modules will not be influenced. Under the control of the method, the level number of the converter of N sub-modules of a single bridge arm can be improved from (N+1) levels to (2N-2) levels, and the level number is nearly doubled.

Description

technical field [0001] The invention relates to a level number multiplication method and a start-up method of a half-bridge sub-module modularized multilevel converter. Background technique [0002] With the development of fully-controlled power electronic devices and the application of power electronic technology in power systems, the flexible DC transmission technology based on voltage source converters has been paid more and more attention. Modular multilevel converter is a kind of voltage source converter in the application of flexible DC transmission system. It is composed of multiple half-bridge or full-bridge sub-modules connected in a certain way, and each sub-module is controlled separately The switch-on and switch-off states of the IGBT components make the AC voltage output by the converter approach to a sine wave, realizing efficient energy transmission. [0003] The application of modular multilevel converters in low-power applications will encounter the problem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/483H02M1/36
Inventor 张建张浩吴金龙刘欣和王先为杨美娟李道洋
Owner XJ ELECTRIC
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