Flexible virtual capacitance control method for stabilizing DC microgrid bus voltage fluctuation

Abstract

The invention provides a flexible virtual capacitance control method for stabilizing DC microgrid bus voltage fluctuation. The method is used for a DC microgrid formed by a new energy power generationunit, a storage battery energy storage unit, an AC and DC load unit and an AC main network, and is characterized by, to begin with, constructing a stable operation constraint set according to actualsituations of the system, and establishing a stable operation index set meeting multiple constraints under virtual capacitance control and calculating a system stable operation boundary; and then, calculating a key control parameter value in real time within the boundary by utilizing a constructed function and importing the key control parameter value into the virtual capacitance control, therebyrealizing flexible real-time adjustment of virtual capacitance and achieving a purpose of suppressing voltage leap of the DC microgrid. The method reasonably calculates the key control parameter valueon the premise of meeting the system safe and stable operation constraint conditions, and flexibly adjusts the virtual capacitance in real time according to fluctuation of voltage change rate of a DCbus. The method can better suppress the DC voltage leap and provides flexible and reliable inertia support for the DC micro-grid.

Description

technical field [0001] The invention relates to a control method for stabilizing bus voltage fluctuations, and belongs to the technical field of control. Background technique [0002] With the deterioration of the ecological environment and the change of energy structure, distributed power generation technology has gradually attracted people's attention. Compared with the AC microgrid, the DC microgrid is more efficient in terms of distributed power access, and there are no problems such as frequency, phase synchronization, and three-phase imbalance. It has a simple structure and high reliability. However, due to the intermittent nature of distributed energy sources and frequent changes in loads, the system power will fluctuate, which will affect the stability of the DC bus voltage and the normal operation of the system. In order to solve this problem, virtual capacitor control came into being. Virtual capacitor control is also virtual inertia control in DC power grid, and ...

AI Technical Summary

Problems solved by technology

The existing virtual capacitor control methods cannot meet the above requirements. Therefore, the flexible virtual capacitor control method under the constraints of multiple indicators is studied, and the key control parameters of the virtual capacitor are adjusted in real time according to the system disturbance to provide flexible inertial support for the DC microgrid. It will be of great significance to the safe and stable operation of the DC microgrid

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