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Judgment method of oscillation stability of converter grid-connected system based on complex circuit modal power

A technology of converters and modeling methods, applied in the direction of reducing/preventing power oscillation, circuit devices, AC network circuits, etc., can solve the problem of no analysis influence, no explanation of complex circuit series-parallel resonance mechanism, difficult small interference stability improvement Strategy and other issues to achieve clear physical mechanism and ensure safe and stable operation

Active Publication Date: 2020-08-11
ZHEJIANG UNIV
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this theory does not explain the mechanism of series-parallel resonance in complex circuits, nor does it analyze the influence of each generalized admittance on resonance, which makes it difficult to evaluate the small disturbance stability of the system based on complex circuits and propose corresponding improvement strategies

Method used

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  • Judgment method of oscillation stability of converter grid-connected system based on complex circuit modal power
  • Judgment method of oscillation stability of converter grid-connected system based on complex circuit modal power
  • Judgment method of oscillation stability of converter grid-connected system based on complex circuit modal power

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specific Embodiment

[0034] According to the specific embodiment that the content of the method of the present invention is fully implemented is as follows:

[0035] Build the grid-connected model of the converter in Matlab / Simulink software, such as figure 1 shown. The converter adopts a dual-loop vector control strategy based on a phase-locked loop, such as figure 2 As shown, and the power factor of the output power of the converter is 1. figure 1 and figure 2 The physical meaning of each variable is shown in Table 1 below:

[0036] Table 1 Correspondence table of converter grid-connected system variables

[0037]

[0038]

[0039] The parameter values ​​of the variables in the converter grid-connected system are shown in Table 2 below:

[0040] Table 2 The parameter values ​​of the converter variables in the simulation verification of the embodiment

[0041] parameter Example 1 Example 2 System capacity base value S b

1500kVA 1500kVA Reference volt...

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Abstract

The invention discloses a converter grid-connected system oscillation stability judgment method based on complex circuit modal power. The method includes adopting a broad sense impedance modeling method to establish an equivalent primal-dual complex circuit of a converter grid-connected system, calculating the generalized admittance modal power according to a voltage equation at a node in the equivalent primal-dual complex circuit of the converter grid-connected system, then calculating the sum of the real parts of the modal power of the generalized admittances and judging the stability of theoscillating resonance of the equivalent primal-dual complex circuit according to plus or minus state as the stability of the converter grid-connected system. According to the method, the physical mechanism is clear, and the modal power can correctly judge the stability of the system and can be applied to analyze the small interference stability of the converter grid-connected system to ensure safe and stable operation of the system.

Description

technical field [0001] The invention relates to a method for judging the stability of a converter grid-connected system, in particular to a method for analyzing the stability of small disturbances of the system by calculating the complex circuit modal power of the converter grid-connected system. Background technique [0002] As global energy problems and environmental pollution problems continue to intensify, renewable energy represented by photovoltaics and wind energy has been applied on a large scale. As renewable energy is connected to the AC grid relying on power electronic equipment, the coupling between power electronic equipment and the grid system is intensified, resulting in a decrease in the voltage support capacity of the AC grid, which in turn causes problems such as system oscillation, posing a major threat to the safe and stable operation of the system. . Therefore, it is urgent to propose a method for analyzing the grid-connected stability of the converter,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38H02J3/24
CPCH02J3/24H02J3/382H02J2203/20
Inventor 辛焕海董炜杨超然宫泽旭
Owner ZHEJIANG UNIV