Research On Coordinated Control Strategy For Multi-port Energy Router

With the wide application of distributed energy generation and its matching energy storage devices,the penetration of new loads such as electric vehicles into the electrical grid and the introducing of electricity marketing reformation,the form of power supply and the direction of energy flow begin to diversify,and traditional power networks and its equipment can not meet the demands of diversity and complexity of power control.To solve this problem,the concept of energy Internet was born.As the key equipment of the energy Internet,the energy router has important research value.In this paper,how to realize coordinated control and stable operation of multi-port energy routers in the case of multiple types of energy access and multi-directional energy flow is deeply studied.For the needs of multiple types of energy access and power allocation,a multiport energy router topology is choosen in this paper,combined with the energy transfer characteristics of the system,the circuit parameters design of the interface converter for photovoltaic,battery and power grid is completed.Around the DC bus voltage regulation,maximum power tracking,multi-target AC grid connection and other control objectives,the characteristics of the access energy and the control methods of each interface converter are deeply studied.Through the research on photovoltaic cells,the control method of photovoltaic power generation unit to realize maximum power point tracking and bus voltage control based on photovoltaic characteristics is designed.Through the research on the battery characteristic model and the common charge and discharge modes,a multi-objective control method for realizing charge and discharge control of the energy storage unit and DC bus voltage regulation is designed.By analyzing the working mode of AC/DC converter unit,a multi-target control method for DC voltage regulation and power control of bidirectional DC/AC converter is designed.The simulation results show that the control methods selected in this paper can effectively complete the preset control objectives,and the steady st ate and dynamic performance are perfect.The advantages and disadvantages of the traditional control strategy are analyzed,and based on the research on the characteristics of the energy access to each functional unit and the control method of the converter,a coordinated control strategy combining master-slave control and hierarchical control is proposed.The system is divided into the underlying control layer and the central management layer.The underlying control layer is responsible for controlling each converter,and the control method is determined by the central management layer;the central management layer summarizes the system information for modal judgment,and issues control commands to the bottom layer only when switching is required;in each working mode,the converters cooperate harmoniously,and one of the converters controls the bus voltage.The typical working mode is simulated in software.The simulation results show that the coordinated control strategy can realize the flexible flow of multi-port energy and the stable operation of the system,which is feasible.The hardware platform suitable for this subject is designed and set up.On this platform,the experiment of converter-level control method and system-level coordinated control strategy proposed in this paper is carried out under typical working mode.The experimental results verify its effectiveness.