A Control Method of Average DC Voltage of Commutation Chain Based on Negative Sequence Current

A negative-sequence current and DC voltage technology, applied in the field of power electronic device control, can solve problems such as unclear control effect and unclear control principle, and achieve the effect of excellent control performance, wide application range, and simple and clear control principle

Active Publication Date: 2014-10-08
CHINA ELECTRIC POWER RES INST +1
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  • Claims
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Problems solved by technology

Three-phase balance control using reactive current feedback, the control principle is not clear, and the control effect is not obvious

Method used

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  • A Control Method of Average DC Voltage of Commutation Chain Based on Negative Sequence Current
  • A Control Method of Average DC Voltage of Commutation Chain Based on Negative Sequence Current
  • A Control Method of Average DC Voltage of Commutation Chain Based on Negative Sequence Current

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Embodiment Construction

[0018] The control method of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0019] The system voltage, link DC voltage, and converter output current in the content are all obtained by the measurement link. When the electrical quantity signal is used to achieve the control target, it has been filtered and reduced.

[0020] In order to more clearly explain the working principle of the method for controlling the average DC voltage of the converter chain based on the negative sequence current of the present invention, the cascaded H-bridge STATCOM converter system is taken as an example for analysis and explanation. The STATCOM structure is as attached figure 1 Shown. Each phase is composed of N cascaded single-phase inverters with independent DC capacitors connected in series. The three-phase commutation chain adopts star connection. Whether the neutral point n of the converter is grounded or not will not affect the con...

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Abstract

The invention particularly relates to a negative-sequence-current-based control method of conversion chain average direct voltage. The method comprises the following steps: comparing the average direct voltage of any two phases of three phases of conversion chain with the average value of direct current of all chain nodes to obtain average direct voltage deviation of the two phases of conversion chain, and processing by a PI (Proportional Integral) controller to obtain the active power deviation of the corresponding phase of conversion chain; combining the active power deviation and the effective value of alternating current side system voltage to obtain the negative-sequence current component instruction of the three phases of conversion chain through the negative-sequence current instruction calculation; transforming the of three-phase negative-sequence current component instruction into dq axis component of negative-sequence current instruction through Park Transform; obtaining the dq axis component of negative-sequence modulation wave voltage through negative-sequence current decoupling control; then carrying out inverse Park Transformation to obtain the reference value of the three-phase negative-sequence modulation wave voltage; and controlling the output of a converter to form a closed-loop control. The method can effectively solve the problem of conversion chain average direct voltage unbalance and has the characteristics of excellent control performance and wide application range.

Description

Technical field [0001] The invention belongs to the technical field of power electronic device control, and specifically relates to a method for controlling the average DC voltage of a converter chain based on a negative sequence current, which can be applied to control the DC voltage of a chain converter. Background technique [0002] The chain converter is widely used in engineering. It is composed of multiple single-phase converter chains, and each single-phase converter chain consists of at least one single-phase module (ie figure 1 In the cascade module 1...n) constitute, each single-phase module includes at least one chain link, the chain link and the chain link can be connected in series or parallel, and each chain link includes H Bridge type voltage source converter. [0003] The chain converter has many advantages, which can realize independent phase separation control, which is helpful to solve the problem of system phase balance. The basic unit structure of all links is...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/48
Inventor 周飞邓占锋宗波蔡林海荆平刘隽胡为进包海龙吴家华
Owner CHINA ELECTRIC POWER RES INST
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