Grid-connected inverter control method and system based on grid asymmetrical fault

An inverter and asymmetric technology, which is applied in the field of grid-connected inverter control based on grid asymmetric faults, can solve the problems of safe operation restrictions endangering the safety of the converter itself, reducing the maximum active power output capability, etc. Easy to apply online, ensure normal operation and longevity, wide range of effects
CN108923456BActive Publication Date: 2021-07-23CHONGQING UNIV
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Patents(China)
Current Assignee / Owner
CHONGQING UNIV
Publication Date
2021-07-23

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Abstract

The present invention provides a grid-connected inverter control method and system based on grid-connected asymmetrical faults, controlling the grid-connected inverter connected between the new energy module and the grid, including: The parameter limit value of safe power transmission by the grid, including the limit value of active power fluctuation range and the maximum phase current limit value; according to the type of fault and the degree of drop, the upper limit value of active power output of the grid-connected inverter and the positive and negative The proportion of the active power of the grid-connected inverter; the PI adjustment of the DC bus voltage of the grid-connected inverter and its reference value to obtain the active power reference; the reference value of the output current of the grid-connected inverter is determined according to the proportion of the active power reference and the positive-sequence active power ; Drive the grid-connected inverter to output current according to the current reference value. The method and system can ensure the safe operation of the grid-connected inverter in the case of an asymmetric fault of the grid, and ensure the normal operation and service life of the grid-connected converter.
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Description

technical field

[0001] The present invention relates to the technical field of grid equipment control, and more specifically, to a grid-connected inverter control method and system based on grid asymmetric faults. Background technique

[0002] In recent years, with the rapid increase of the proportion of new energy in the power generation capacity of the power grid, its impact on the stable operation of the power grid has become increasingly significant. In order to ensure the stability of the grid, many grid standards require wind turbine converters or photovoltaic systems to have low-voltage ride-through capabilities during faults, and some grid standards also require active power injection for support. Injecting active power can reduce the active power deficit of the power grid and reduce the risk of large-scale collapse of the power grid. In addition, in the case of low-voltage microgrid, the transmission line is resistive, the traditional relationship between voltage a...

Claims

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