Power coupling circuit in unbalanced power grid and control method

A technology of power coupling and control method, applied in the direction of reducing/preventing power oscillation, reducing asymmetry of multi-phase network, eliminating/reducing asymmetry of multi-phase network, etc. Sub-oscillation power, reducing power grid reliability and other issues, to improve power quality and maintain normal operation

Active Publication Date: 2019-08-09
HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the grid voltage is unbalanced, there will be low sub-oscillating power in the DC side of the three-phase converter system
This oscillation work will greatly affect the operation of the DC side equipment, deteriorate the power quality and even reduce the reliability of the power grid.

Method used

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  • Power coupling circuit in unbalanced power grid and control method
  • Power coupling circuit in unbalanced power grid and control method
  • Power coupling circuit in unbalanced power grid and control method

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Embodiment Construction

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] see figure 1 As shown, the embodiment of the present invention provides a power coupling circuit in an unbalanced power grid, a power grid, a main circuit, a power coupling circuit and a DC side circuit.

[0030] Among them, the grid-side circuit has a star-connected three-phase power supply and each phase has a leakage inductance L g The main circuit has a first bridge arm, a second bridge arm and a third bridge arm connected in parallel in sequence, and the first bridge arm, the second bridge arm, and the third bridge arm each include two switching devices, and the first bridge arm and the third bridge arm each include two switching devices. The bridge arms, the center points of the second bridge arm and the third bridge arm are respectively connected to the three-phase grid; the power coupling circuit has a fourth bridge ar...

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Abstract

The invention discloses a power coupling circuit in an unbalanced power grid and a control method, and the power coupling circuit comprises a power grid side circuit which is provided with a three-phase power supply in star connection and each phase is provided with a leakage inductor Lg; a main circuit which is provided with a first bridge arm, a second bridge arm and a third bridge arm which aresequentially connected in parallel, wherein each of the first bridge arm, the second bridge arm and the third bridge arm comprises two switching devices, and central points of the first bridge arm, the second bridge arm and the third bridge arm are respectively connected to a three-phase power grid; a power coupling circuit which is provided with a fourth bridge arm connected to the right side ofthe main circuit in parallel, wherein the coupling bridge arm comprises two switching devices, and a coupling inductor and a coupling capacitor are sequentially connected between the midpoint of thebridge arm and a ground wire in series; and a DC-side circuit having a DC-side capacitor and a load connected in parallel with the main circuit. Oscillation power generated due to imbalance of a powergrid can be completely transferred to the power coupling circuit, the DC-side voltage is maintained to be free of fluctuation, and the electric energy quality is improved.

Description

technical field [0001] The invention relates to the field of power electronic control, in particular to a power coupling circuit and a control method in an unbalanced power grid. Background technique [0002] The widespread use of three-phase three-wire converters makes the smart grid more flexible and controllable, and can obtain a higher power factor, thereby improving power quality. However, when the grid voltage is unbalanced, low sub-oscillating power will appear in the DC side of the three-phase converter system. This oscillation work will greatly affect the work of the DC side equipment, deteriorate the power quality and even reduce the reliability of the power grid. Contents of the invention [0003] The object of the present invention is to provide a power coupling circuit and a control method in an unbalanced power grid in order to overcome the problems raised in the above-mentioned background technology. The present invention adds a power coupling circuit on t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/24H02J3/26
CPCH02J3/24H02J3/26Y02E40/50
Inventor 李俊茆华风张俊敏卢晶沈显顺吴亚楠许留伟傅鹏
Owner HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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