Mode-dependent micro grid multi-mode operation switching control method

Abstract

Provided is a mode-dependent micro grid multi-mode operation switching control method. The output characteristics of various distributed power supplies and the characteristics of signal transmission between the distributed power supplies are analyzed. A micro grid system is decomposed into a dynamic model of subsystems in a hierarchical decomposition approach according to the multi-path power flow of energy inside the micro grid. A networked control model of an inverting micro source and comprehensive state space static and dynamic models of the micro grid under various operation states are built based on a small signal stability method. The stability of the micro grid system in all states and at the moment of state switching and the switching control law for ensuring smooth transition between the states are studied based on a switching system theory. The stability of the micro grid system is well guaranteed at the moment of operation mode switching. The stability control problem and the energy balance and power balance tracking control problem in multi-mode operation of the micro grid are solved. Stable operation of the micro grid and seamless switching between modes are realized to the maximum.

Description

technical field [0001] The invention relates to the fields of power electronics, communication and control, in particular to a mode-dependent micro-grid multi-state operation switching control method. Background technique [0002] The rapid development of the world economy and industry has made the global energy supply continue to be tense. The traditional energy sources such as oil, natural gas, coal and other non-renewable energy are gradually being exhausted. Rational development and utilization of clean and efficient green energy and distributed power generation based on flexible economy DG (Distributed Generation)'s microgrid technology (Microgrid) has become the main way to solve the energy problems in the next century, and has been put on the agenda by various countries. The micro-grid technology based on distributed power generation not only has the advantages of environmental protection, high efficiency, and adapting to local conditions, but also can save the invest...

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Problems solved by technology

[0005] (1) Distributed energy has small capacity, unstable power, uncontrollability and randomness, and is easy to cause fluctuations to the power grid;

[0006] (2) When the micro-grid is connected to the grid, it will cause steady-state voltage fluctuations, transient voltage fluctuations (voltage dips and sags), voltage flicker and the injection of a large number of harmonic pollution, which will seriously affect the stability of grid voltage and frequency;

[0007] (3) When operating in an isolated island, it is difficult for a variety of micro-power sources to quickly track the changes in the load in the micro-grid. The voltage and frequency in the micro-grid will fluctuate greatly without the support of the power grid, and the power quality will decline. electrical equipment and user equipment;

[0008] (4) Due to the plug-and-play flexibility of the distributed power supply and the uncertainty of the grid line impedance, it leads to the imbalance of various parameters in the grid, resulting in a large inductive current circulation between the power sources, so it must be Rapid response to changes in system parameters

[0009] Therefore, in order to maximize the advantages of the micro-grid, improve the acceptance capacity of the grid for distributed new energy, maximize the use of renewable energy and clean energy, realize the multi-objective operation of the micro-grid, and ensure the stability of the multi-state of the micro-grid, It is necessary to solve the problem of power quality deterioration caused by overcurrent and transient voltage peak mutations during mode switching. It is necessary to address the complex dynamic characteristics of the microgrid, variable operating structures, and diverse control targets. Based on the inverter micro-source Distributed control realizes bumpless switching of multi-objective microgrid multi-state operation

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