Grid-connected power recovery method and device for controlling photovoltaic inverter

Abstract

The invention discloses a grid-connected power recovery method and device for controlling a photovoltaic inverter. The method comprises the following steps of: after low-voltage ride through is over, setting the voltage given value Vtarget of a photovoltaic panel group string to be smaller or equal to opening voltage Vopen; taking the voltage given value Vtarget of the photovoltaic panel group string and the output voltage Vpv of the photovoltaic panel group string as a deviation to control the output voltage Vpv of the photovoltaic panel group string to be stabilized at the voltage given value Vtarget; reducing the voltage given value Vtarget of the photovoltaic panel group string to a voltage given value VMppSet corresponding to a maximum power point before low-voltage ride through; and controlling the output voltage Vpv of the photovoltaic panel group string to be stabilized at the voltage given value VMppSet. According to the method the device, the grid-connected power can be quickly recovered after the low-voltage ride through is over, the problem of inverter bus breakdown caused when the power is reduced is effectively solved, and the method and the device have the advantage of being easy to realize.

Description

technical field [0001] The invention relates to a photovoltaic control technology, in particular to a method and a device for controlling the rapid recovery of grid-connected power of a photovoltaic inverter after a low voltage ride-through occurs. Background technique [0002] Low-Voltage Ride Through (LVRT, Low-Voltage Ride Through) means that when the voltage at the grid-connected point drops, the photovoltaic inverter can maintain grid-connection, and even provide a certain amount of reactive power to the grid to support the recovery of the grid until the grid returns to normal , thus "passing through" this low voltage time (area). LVRT is a specific operational functional requirement for photovoltaic inverters to remain connected to the grid even when the grid voltage drops. Different countries (and regions) have different requirements for LVRT. When the voltage is in the concave part, the inverter should provide reactive power. [0003] At the same time, when the lo...

AI Technical Summary

Problems solved by technology

[0005] The present invention proposes a method and device for controlling the rapid recovery of the grid-connected power of the photovoltaic inverter after the end of the low-voltage ride-through, so as to solve the problem that the existing technology cannot recover to the maximum power point and may cause the bus voltage of the inverter to collapse question

Images