Research On Energy Router Control Strategy Of AC/DC Distribution Network

Energy Internet helps to achieve in-place consumption of distributed power sources,multiple access of load types and reduce consumption of fossil energy.AC/DC distribution network is one of the applications of energy internet.The energy router in AC/DC distribution network uses a multi-port structure to provide flexible access to different types of power sources and loads.The integrated control strategy of energy router is one of the important research directions.This thesis mainly studies the virtual motor control strategy of energy router in AC/DC distribution network.On the basis of studying the structure of AC/DC distribution network,this thesis combines the characteristics of AC/DC distribution network to determine the circuit topology of the energy router and further determines the components of the energy router.Among them,the medium voltage AC input stage uses MMC rectifier structure to meet the voltage level requirements;the medium voltage DC input stage uses MMC-BDC structure;the intermediate isolation stage uses DAB-based input-seriesoutput parallel structure to achieve voltage isolation and energy transmission;the low voltage output stage DC interface uses BDC structure and the AC interface uses LC three-phase inverter circuit.In order to improve the dynamic performance of the energy router,virtual synchronous motor control strategy and virtual direct current motor control strategy are used in the control link of AC inverter and DC converter,respectively.Based on the flexibility of virtual parameters in virtual motor control strategy,the selection principle of virtual parameters is studied and put forward.Based on the RLS algorithm,a parameter adaptive controller is designed on the basis of theoretical research and a virtual motor control schematic diagram based on the parameter adaptive controller is built to actively participate in power grid voltage,frequency and power regulation by the energy router.In this thesis,a simulation model of energy router for AC/DC distribution network is built under the MATALB/Simulink environment and the simulation analysis is carried out with the control strategy.The simulation results show that when load switching,voltage fluctuation and grid connection occur at the interface of the energy router and the virtual motor control strategy studied in this paper is more helpful to improve the stability of bus voltage,grid frequency and power in AC/DC distribution network than the PQ control strategy and the double-loop control strategy.