Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM

A control method and voltage balancing technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., can solve the problem of not completely solving the space vector midpoint potential balance small vector, etc., to achieve voltage The effects of small stress, increased application voltage level, and small change in voltage slope

Inactive Publication Date: 2014-09-10
STATE GRID CORP OF CHINA +2
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Problems solved by technology

However, the neutral point voltage offset is the main shortcoming of the neutral point clamped three-level converter. According to the current research, it is known that the small and medium vectors in the space vector have an impact on the neutral point potential, but the current research has not completely solved the problem of the entire space Vector Midpoint Potential Equilibrium and Effect of Small Vectors on Midpoint Potential

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  • Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM
  • Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM
  • Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM

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Embodiment Construction

[0035] The SVPWM-based midpoint voltage balance control method on the DC side of the three-level converter of the present invention comprises the following steps:

[0036] 1) Analysis of the SVPWM control mechanism and the influence of the switching state on the midpoint potential: Through the analysis of various switching states of the three-level converter, it can be known that the medium vector and the small vector have an impact on the midpoint current, and the zero vector and the large vector have an impact on the midpoint potential. The midpoint current has no effect;

[0037] 2) Space voltage vector partition judgment: Aiming at the problem that each small vector corresponds to the opposite effect of the load current on the neutral point current under two switch-like bodies, a method of canceling the medium vector is proposed, and the small vector and large vector are used to synthesize Participate in vector and sector division methods;

[0038] 3) Determine the action...

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Abstract

The invention discloses a three-level converter direct-current side neutral-point voltage balance control method based on SVPWM, and belongs to the technical field of electric system power electronics. According to the method, median vectors are eliminated, and small vectors and large vectors are combined to form a reference voltage vector. The method comprises the steps of analyzing the influence of an SVPWM control mechanism and the on-off state on the neutral-point potential, partition judgment is carried out on voltage space vectors, determining the action time of each space vector, and determining the vector sending sequence. By means of the method, change of the on-off state of a power device and loss of a converter are reduced, neither a voltage sharing circuit nor a hardware circuit is needed, and the dynamic balance performance of the direct-current side voltage of the three-level converter is improved. The control method is simple and has great reference value for engineering application.

Description

technical field [0001] The invention belongs to the technical field of electric power electronics. Background technique [0002] With the continuous development of power electronics technology, large capacity, high efficiency, and high performance have become the mainstream of development. In high-voltage and large-capacity applications, traditional two-level converters need to step up or down the voltage through intermediate transformers, which not only increases equipment investment, but also reduces system efficiency. In order to overcome these disadvantages, the converter switching devices are required to have higher voltage stress, but this method has static and dynamic voltage equalization problems, so the application of multi-level converters arises. [0003] Due to the increase in the number of output voltage levels of the multi-level converter, the output waveform of the converter is closer to a sine wave, and the switching stress on the device is reduced. There is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/487
Inventor 李卫李卫国王吉陈厚合辛业春邵刚陈雪松
Owner STATE GRID CORP OF CHINA
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