High precision impedance measuring device based on UPQC and switching control method thereof

Abstract

The invention discloses a high precision impedance measuring device based on UPQC and a switching control method thereof. The abovementioned device comprises a UPQC disturbance injection unit, a signal processing unit, a broadband impedance calculating and monitoring unit, and a control unit. The serial connection side of the UPQC disturbance injection unit is serially connected with a to be measured system by a coupling transformer, and the parallel connection side thereof is directly parallely connected with the to be measured system. When impedance of a power grid is higher than impedance of to be measured equipment, current disturbances are injected in the parallel connection side, and the serial connection side is used to stabilize direct current side voltage; when the impedance of the power grid is lower than the impedance of the to be measured equipment, the current disturbances are injected in the serial connection side, and the parallel connection side is used to stabilize thedirect current side voltage, and then the disturbances are distributed on the side of the to be measured equipment at high proportion to improve impedance measuring precision.

Description

technical field [0001] The invention relates to the technical field of impedance measurement in new energy power generation, in particular to a switching control method of a high-precision broadband impedance measurement device. Background technique [0002] With the depletion of fossil energy and the intensification of environmental problems such as global warming, the development and utilization of new energy has become the best choice for people to seek energy structure adjustment and achieve sustainable development. When analyzing large-scale new energy power generation equipment connected to the grid, the impedance characteristics of the grid have an important impact on the stable operation and control of power electronic equipment such as wind power and photovoltaic grid-connected inverters. Ideally, the grid should behave as an ideal voltage source, and the new energy power generation equipment should be controlled as an ideal current source to avoid any impedance int...

AI Technical Summary

Problems solved by technology

When performing impedance frequency sweeping, especially when measuring the impedance of the grid-connected interface unit of new energy power generation equipment, the impedance of the high-frequency power grid will be higher than the impedance of the equipment to be tested. In this case, the accuracy of the wide-band frequency sweeping results cannot be taken into account. sex

Considering that in the low frequency band, the impedance of the equipment to be tested is higher than that of the grid; To solve the problem of wide-frequency domain impedance measurement equipment, the present invention proposes a switching control method for high-precision impedance measurement devices based on UPQC

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