MMC-based megawatt-level broadband impedance measurement device and its control method

Abstract

The invention discloses a megawatt-grade broadband impedance measuring apparatus based on MMC, and a control method thereof. The impedance measuring apparatus includes a current disturbance injectionunit, wherein the current disturbance injection unit includes an MMC converter and an isolation branch circuit which is connected with the MMC converter; each phase half-bridge arm of the MMC converter includes one reactor and four sub modules in series; the reactor is connected with the sub modules in series; the isolation branch unit includes a Y-Y type isolation transformer with respective phase change ratio 1; the auxiliary edge of the Y-Y type isolation transformer is connected with an RC circuit in parallel; and each phase original edge of the Y-Y type isolation transformer is connectedwith the corresponding phase bridge arm of the MMC converter. The megawatt-grade broadband impedance measuring apparatus based on MMC satisfies the refinement requirement of a generating equipment simulation model in a new energy generating base, and fills the gap on an accurate measuring method and equipment for high voltage, megawatt-grade and broadband impedance characteristic.

Description

technical field [0001] The invention relates to the technical field of impedance measurement in new energy power generation, in particular to an MMC-based megawatt-level broadband impedance measurement device and a control method thereof. Background technique [0002] In order to cope with the depletion of fossil energy, wind, light and other new energy power generation has achieved large-scale and rapid development in recent years. When large-scale new energy power generation devices are connected to the grid, the impedance characteristics of the grid have an important impact on the control and stable operation of power electronic equipment such as wind power and photovoltaic grid-connected inverters. In an ideal situation, the new energy power generation equipment should be controlled as an ideal current source, and the power grid should behave as an ideal voltage source to avoid the problem of impedance interaction coupling. However, in reality, the areas rich in new ene...

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Problems solved by technology

At present, the number of diversified new energy power generation equipment is huge, the control is complex, and there are multi-time scale couplings. The external characteristics of different power generation equipment are very different, and factors such as energy fluctuations of new energy and grid disturbances make the measurement of impedance characteristics of power generation equipment more complicated. , there is a lack of impedance characteristic data for power generation equipment such as megawatt-level wind turbines and photovoltaic power generation units, and it is difficult to meet the refinement requirements required for the simulation model of power generation equipment in new energy power generation bases. Accurate measurement methods and equipment are blank at home and abroad, and key technologies need to be broken through

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