Modeling And Stability Analysis Of Network-based Microgrid

With the over-exploitation of fossil energy and the deterioration of the environment,more and more countries have begun to vigorously develop power generation technology using renewable energy.As one of the effective carriers,the microgrid has attracted great attention.From the initial independent distributed power generation unit to the intelligent network operation of multiple microgrids,microgrids have become an indispensable part of modern power systems that urgently need to improve the reliability and flexibility of power supply.Therefore,the research and application of microgrids is imminent.This thesis takes the microgrid as the research object to study the access and removal of the microgrid and the stability and control strategy of the microgrid control system under networked.The main contents are as follows:(1)In view of the random access or exit of distributed power generation units in intelligent microgrids,a pluggable control strategy is given,and the method is only required to design the controller with limited global parameters,so the design process of the controller is decentralized and more suitable for the dispersion characteristics of the micro-source units in microgrid.In addition,the stability of the closed-loop system is proved by the Lyapunov method.Finally,simulation verification was carried out by MATLAB/Simulink.(2)A microgrid event trigger optimization and control method based on asynchronous sampling data system is proposed for network control problems,such as delay and bandwidth limitation,which result from the network of micro-source units or distributed power generation units in microgrid,and the event triggering system is established,taking into account the delay caused by the network in the channel and interference in the model.Set the cost threshold as the trigger condition,use the particle swarm optimization algorithm to balance the control cost and communication cost,reduce the event rate and save communication resources.Finally,the effectiveness of the design is verified by using the MATLAB/Simulink simulation platform.(3)In view of the packet loss problem existing in the network-based microgrid system,a robust_∞control method of microgrid networked control system in the case of random packet loss is given.Assuming that there is a drop-packet phenomenon in the sensor-to-controller,controller-to-actuator,the idea of robust control is adopted and the drop process is modeled as the Bernoulli drop-packet model,and the stability analysis is carried out using the Lyapunov function and the network control system is index-stabilized in the mean meaning.Finally,the validity of the method given is verified by the MATLAB/Simulink simulation example.Finally,this thesis makes a corresponding summary of the work done and looks forward to the future development of microgrid.