Island detection method of high-power photovoltaic grid-connected converter

An island detection and converter technology, which is applied in the field of photovoltaic power generation system control and island detection, to achieve the effect of being conducive to power stability, ensuring rapidity and reliability

Active Publication Date: 2012-05-02
WUHAN NEW ENERGY INST OF ACCESS EQUIP & TECH
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Problems solved by technology

However, the above-mentioned various detection methods have advantages and disadvantages, a

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  • Island detection method of high-power photovoltaic grid-connected converter
  • Island detection method of high-power photovoltaic grid-connected converter
  • Island detection method of high-power photovoltaic grid-connected converter

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Embodiment Construction

[0029] In order to make the content of the present invention more clearly understood, the technical solutions of the present invention will be further described in detail below according to the specific embodiments of the present invention and in conjunction with the accompanying drawings.

[0030] In this embodiment, a 250kW photovoltaic grid-connected power generation converter is taken as an example to illustrate the islanding detection method and actual implementation proposed by the present invention. Such as figure 2 Shown, this method is realized according to the following steps in digital signal processor DSP:

[0031] Step (1), in the photovoltaic grid-connected three-phase converter, the three-phase voltage Ua, Ub, Uc of the grid is locked in real time by using a software phase-locked loop (SPLL) based on a digital delay signal cancellation algorithm (DSC) Grid frequency f and positive sequence phase angle θ;

[0032] Step (2), judging whether the system is workin...

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Abstract

The invention discloses an island detection method of a high-power photovoltaic grid-connected converter. The method comprises the following steps of: determining whether a system operates at a grid-connected power generation state, and starting up an island detection algorithm instantly if the system is at the grid-connected power generation state; detecting whether the frequency of the voltage of a port power grid is within the normal range in real time, if the frequency is not within the normal range, considering that the system is at the island state, and carrying out automatic safety stop on the system; adding reactive current Iqdisturb with the duration of td periodically within the normal range; and superposing the reactive current Iqdisturb and reactive control Icqset of the converter, thus an axis q component reference Icqref of grid-connected current of the converter is formed finally. The contradiction between two aspects of reliability of detection and the quality after grid-connected electric energy reduction for the traditional island detection algorithm is effectively solved by the method provided by the invention, and the implementation method is simple and effective.

Description

technical field [0001] The invention relates to an island detection method, in particular to an island detection method for a high-power photovoltaic grid-connected converter, and belongs to the application field of photovoltaic power generation system control technology. Background technique [0002] Solar energy is widely distributed and easy to be used by people. Among many new energy sources, solar energy has become the focus of people's attention due to its unique advantages. The development and utilization of solar energy will help mankind gradually get rid of dependence on traditional energy sources and embark on the road of sustainable development, which has important strategic significance. [0003] As the capacity and number of photovoltaic grid-connected power generation systems using solar energy continue to increase, the problem of isolated islands is becoming more and more prominent. Power islands may bring the following hazards: on the one hand, because the g...

Claims

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Application Information

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IPC IPC(8): H02J3/38G01R31/00
CPCY02E10/563Y02E10/56
Inventor 揭贵生吴振兴汪光森胡安林城美周亮阳习党朱威杨华
Owner WUHAN NEW ENERGY INST OF ACCESS EQUIP & TECH
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