Method for islanding microgrid control and optimization based on rotating coordinate virtual impedance
A technology of virtual impedance and rotating coordinates, which is applied in the field of microgrid to achieve power decoupling, improve accuracy, and improve impedance characteristics
A technology of virtual impedance and rotating coordinates, which is applied in the field of microgrid to achieve power decoupling, improve accuracy, and improve impedance characteristics
CN102623992AInactive Publication Date: 2012-08-01SHANDONG UNIV
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[0034] The present invention will be further described below in conjunction with accompanying drawings and examples.
[0035] figure 1 It is a schematic diagram of a typical microgrid structure, which includes three typical distributed power sources (DG1-DG3) of wind turbines, photovoltaic cells, and fuel cells, and three loads in different positions. The impedance of each line is z 1 -z 5 . In this paper, each distributed power source is assumed to be a DC source or a rectified DC source, which is converted into a three-phase AC by the SVPWM inverter and filtered by an LCL low-pass filter, and then connected in parallel to the AC of the microgrid. It is connected to the main grid at the point of common connection PCC through a static transfer switch. figure 2Thevenin equivalent circuit for distributed generation connected to microgrid AC bus. In the figure, E∠φ is the open circuit voltage of the inverter, U∠0 is the AC bus voltage, Z and θ are the amplitude and phase an...
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The invention discloses a method for islanding microgrid control and optimization based on rotating coordinate virtual impedance. Aiming to a fact that the actual microgrids have complicated impedance characteristics, the method for islanding microgrid control and optimization based on the rotating coordinate virtual impedance includes utilizing the coordinate rotation orthogonal transformation to design the coordinate rotation virtual impedance, improving the impedance characteristics of the microgrid, compensating errors of power distribution and improving power decoupling performance; establishing a complete small-signal dynamic model of the microgrid, wherein the small-signal dynamic model comprises distributed energy sources, power converters, loads and power grids, and guiding the selection of an optimal value on the basis of the small-signal dynamic analytical method; and simultaneously, providing a theoretical basis for the optimization selection of islanding microgrid control parameters by using the small-signal dynamic analytical method, wherein the islanding microgrid control parameters comprise droop control coefficients of the power distribution, process identifier (PI) parameters of a voltage current feedback controller, feedforward control coefficients and the like. The microgrid after being subjected to optimization design in an islanded operational mode is capable of effectively achieving power decoupling and improving the accuracy of the power distribution, the stability of the system and the dynamic performances.
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technical field [0001] The invention belongs to the technical field of micro-grids, and in particular relates to an island micro-grid control and optimization method based on rotating coordinate virtual impedance. Background technique [0002] Under the dual pressure of energy demand and environmental protection, distributed energy supply technology that can not only improve the utilization rate of traditional energy but also make full use of various renewable energy sources has gained more and more attention and application. The microgrid is composed of distributed generators (Distributed Generators, DGs), energy storage devices, energy conversion devices, related loads and monitoring and protection devices, which can give full play to the technology, economy and environment that DG brings to the power system and users. It is an important part of smart grid construction to further improve the flexibility, efficiency and cleanliness of power system operation, and better meet...
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Patent Timeline
01 Aug 2012
Publication
CN102623992A
- IPC
- H02J3/00; H02J3/38
- CPC
- Y02P80/14
- Inventors
- 张承慧; 王瑞琪