Control method of low voltage microgrid inverter based on adaptive virtual impedance

Abstract

The invention belongs to the field of the inverter power supply in the field of microgrid, relates to inverter power output control and protection under the low voltage impedance environment, particularly relates to a control method of a low voltage microgrid inverter based on adaptive virtual impedance, and solves the problems in the background technology. The rectangular pulse trigger signals ofthe a, b and c phases of all the switching tubes obtained by cooperative control of the PQ power decoupling control, the transient current limiting control, the steady-state current sharing control and the power angle cooperative control act on a three-phase chopping bridge, thereby realizing the power control of the inverter under the low voltage microgrid. The adaptive virtual impedance is constructed on the basis of decoupling and drooping control of the inverter, and the power angle is adjusted according to the change intensity of the adaptive virtual impedance to perform cooperative control so as to improve the power equalization degree and the current limiting stability in case of grid connection of the inverter.

Description

technical field [0001] The invention belongs to the field of inverter power sources in the field of micro-grids, and relates to inverter power output control and protection in a low-voltage resistive environment, in particular to a control method for a low-voltage micro-grid inverter based on adaptive virtual impedance. Background technique [0002] With the development of distributed energy, a microgrid (referred to as a microgrid) that integrates micro-sources, energy storage, and local loads suppresses power fluctuations during grid connection and improves the reliability of power supply for local loads. The microgrid can be disconnected from the main grid during operation and independently meet the local load demand. In the case of off-grid, it is necessary to distribute the output of each micro-source according to the change of load or characteristic quantity in the grid, and at least one micro-source can quickly respond to load changes to suppress voltage and frequency...

AI Technical Summary

Problems solved by technology

In order to make the microgrid have better control performance, in the dual-loop control of the original feedback current using the voltage outer loop and the current inner loop, an adaptive virtual impedance is added, that is, the output voltage is changed to achieve the effect of the actual impedance. In the inverter Adding adaptive virtual impedance to dual-loop control is relatively mature in the existing technology, but there are still some problems. For example, in traditional control, the setting value of adaptive virtual impedance is a fixed value, which cannot effectively deal with various situations or can only consider high voltage. Power control in an inductive environment, the resistive inductive environment of low-voltage feeders often leads to the failure of traditional droop control

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