Research On Control Strategy Of Energy Router Based On Virtual Synchronous Genreator

With the rapid development of renewable energy power generation and the emergence of new load,the power network structure has become more and more complex.In order to cope with the complex and diverse condition in power demand,experts from various countries put forward the idea of creating the Energy Internet.It is necessary to study the connecting equipment of various energy networks for realizing the structure of the Energy Internet.This article explores the energy router that the key equipment in researching.The energy router system can operate safely and steadily,via the research and design of topology,the AC/DC interface control strategy and energy management strategy for distributed power supply in the paper.In this paper,a bidirectional energy router topology structure is used.First of all,its topology is studied in detail.An isolated bidirectional full bridge DC/DC chopper is used for the power electronic converter at the DC side port of the topology structure to realize the two-way flow of energy.A three-phase bridge inverter is used at AC side port to output three-phase power frequency power for the AC interface.In this paper,the working principle and control mode of each port converter are analyzed in detail,and the mathematical model of each port converter is deduced in detail.The Virtual Synchronous Generator(VSG)is introduced for the power electronic converter of the energy router's AC interface.By listing the mathematical model of synchronous generator,the VSG control ontology control algorithm is designed by analogy and the key parameters are analyzed.The corresponding virtual governor and virtual exciter are designed on this basis.The AC inverter has the characteristics of inertia and damping,and can participate the system voltage regulation and frequency modulation by using the improvement control algorithm.Then,a full order sliding mode control loop is proposed to enhance the stability and robustness of the system based on the VSG algorithm.The simulation results show that the frequency support performance of VSG control is better than that of droop control.The output of sliding mode control has higher power quality compared with the traditional PI loop.In order to maintain the stable operation of the DC port,DC virtual motor control is introduced in this paper to control the DC/DC chopper at the energy storage interface.By listing the mathematical model of the DC motor,an analog control algorithm for the virtual DC motor is designed analogously,simultaneously a corresponding voltage and current loop are designed so that it can achieve)the control target of the stable DC bus voltage.Through the comparison and analysis with DC side droop control algorithm,it can be known that the DC virtual motor control algorithm has DC bus voltage inertia characteristics and strong disturbance suppression capability,which is conducive to the safe operation of the power system.Finally,this paper studies the DC port energy management strategy of energy router system.This strategy uses the photovoltaic power generation system as the main output module,the wind power generation system assists the power generation module,and the energy storage system suppresses power fluctuations to realize the orderly distribution of the output energy of each distributed power supply.The simulation results verify the correctness and effectiveness of the strategy.