Research On Hybrid Micro-grid Based On Simultaneous AC And DC Distribution Network And Its Power Router

With the contradiction between the development and the demand of traditional energy and the pressure of environmental protection,the research and application of renewables are more and more concerned.The distribution of new energy power generation is generally fluctuating;randomness and uncertainty have put forward new requirements for distribution system.At the same time,with the change of energy consumption structure,the distribution network based on "source-Net-load-storage"becomes one of the future development directions of power grid,and the electric power multi-directional flow and power network intelligent control is the development requirement of distribution network.The traditional AC distribution network is more and more unable to meet the diversified power distribution requirements;this paper applies the AC-DC coaxial power transmission technology to the distribution network and then the micro-grid architecture,and analyzes the key problems.Based on the research of simultaneous AC-DC power transmission technology and the development requirement of distribution system,this paper uses this technology to upgrade the traditional AC distribution network,and analyzes the rationality and superiority of the principle structure of the AC/DC line distribution system,and compares the various schemes that can be used to realize the AC/DC line distribution.Based on the key equipment,the principle structure and performance of three kinds of schemes are compared and analyzed;z-type transformer can effectively avoid the transformer iron core saturation caused by DC injection,and ensure reliable electrical isolation.The influence of electrical constraints and DC power superposition on power distribution performance of AC/DC power transmission is analyzed.In order to introduce the micro-grid technology into the AC-DC line distribution,the topology of the hybrid micro-network in AC-DC line is proposed,and the basic principle and operation mode of the micro-power network are analyzed,and the fundamental operation principle and the corresponding control target of the micro-power grid under different operating modes are The hybrid energy storage system and control strategy based on battery and super capacitor are analyzed,which is used to realize power balance control and to stabilize DC bus voltage fluctuation.The rationality and validity of the hybrid energy storage system are verified by MATLAB/simulink simulation.Combined with power electronic technology,a modular multi interface structure of power routers is proposed,which is suitable for AC/DC hybrid micro-network,which guarantees the general expansibility of AC-DC hybrid micro-network,and realizes the power routing control of Micro-grid.In view of the requirements for the structure and performance of power routers in AC-DC parallel hybrid micro-grid,the main circuit structure of power router based on three-phase H-bridge AC-DC transform circuit and dual active DC-DC converter is proposed,and the corresponding control strategy for each power electronic device is put forward to realize the reliable operation control In the MATLAB/simulink simulation software,the AC-DC hybrid micro-grid and its power router model are built,and the rationality and validity of the power router to the micro-network routing control are verified by simulation.