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

Abstract

The invention provides a grid-connected inverter control method and system based on power grid asymmetry fault. The grid-connected inverter control method is used for controlling a grid-connected inverter connected between a new energy module and a power grid and comprises the steps that parameter limiting values of new energy for safely transmitting the electric quantity to the power grid throughthe grid-connected inverter is determined and comprises the active power fluctuation amplitude limiting value and the maximum-phase current limiting value; the proportion of the active power output upper limit value and the positive sequence active power of the grid-connected inverter during the fault is obtained through the parameter limiting values according to the fault type and the dropping degree; PI adjusting is conducted on the direct current bus voltage of the grid-connected inverter and reference values of the direct current bus voltage to obtain active power reference; output current reference values of the grid-connected inverter are determined according to the proportion of the active power reference and the positive sequence active power; and the grid-connected inverter is driven to output the current according to the current reference values. According to the grid-connected inverter control method and system based on the power grid asymmetry fault, it can be ensured thatthe grid-connected inverter operates safely under the situation of the asymmetry fault of the power grid, and normal work and the service life of the grid-connected inverter are ensured.

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...

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Problems solved by technology

Insufficient consideration of safe operation constraints may endanger the safety of the converter itself; strictly limiting the instantaneo

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