GRID-CONNECTED INVERTER AND OVERVOLTAGE SUPPRESSION METHOD THEREFOR

Abstract

Provided in the present application are a grid-connected inverter and an overvoltage suppression method therefor. In the overvoltage suppression method, when an alternating-current port voltage of a grid-connected inverter does not exceed a preset threshold value, the grid-connected inverter is controlled to perform grid-connected operation in a current source mode; when the alternating-current port voltage exceeds the preset threshold value, the grid-connected inverter is controlled to perform grid-connected operation in a voltage source mode, such that a response to a reactive current or reactive power, which is outputted by an alternating-current port of the grid-connected inverter, is realized within a preset duration; and the grid-connected inverter is controlled to resume the current source mode until the reactive current or the reactive power is greater than or equal to a corresponding preset reactive instruction value. Therefore, when a temporary overvoltage occurs in an electric power system, transient voltage source characteristics are constructed, and a power supply characteristic of a grid-connected inverter is used to enable the grid-connected inverter to perform spontaneous reactive injection, so as to greatly reduce a reactive response time so that same is synchronous with a rising speed of an alternating-current port voltage, that is, an instantaneous reactive power support can be achieved, and rapid suppression of an instantaneous overvoltage can thus be achieved.

IPC Classifications