Research On Switching Control Strategy Of Grid-connected/Off-grid For Microgrid Energy Storage Inverter

With the large-scale use of new energy sources,energy storage devices,as a kind of controllable power supply,play a decisive role in ensuring the normal operation of microgrid.For example,For intermittent distributed power sources such as photovoltaic or wind power,energy storage devices are required to balance energy production.It will not only eliminate the peak of energy output,but also fill the valley of output.So this paper studies some key technologies of energy storage devices in microgrid:Firstly,the problems of the traditional PID in engineering application are analyzed,and then the Active Disturbance Rejection Controller technology is introduced.The overall composition of the ADRC is introduced,and the relevant working principles and effects of various parts are analyzed in detail.Aiming at the complexity of the practical application of the ADRC,the improved linear ADRC is introduced.Subsequently,the energy storage inverter control in the energy storage system is studied.Firstly,the structure and working principle of energy storage inverter are introduced,and then its mathematical model is established.When the microgrid energy storage system operates in the grid-connected operation mode and the islanding operation mode,the LADRC controller is designed to control the energy storage inverter.Comparing with traditional PID under the same conditions.Build a simulation model under MATLAB/Simulink simulation platform.The consequence prove that the LADRC has better control manifestation than the PID conetroller.Finally,the main research is on mode switching of energy storage inverters.By installing the circuit breaker module and controlling it,the dual mode switching is completed,and the switching of the control method in the corresponding mode is completed.Researched the specific steps of mutual switching and conducted corresponding analysis.The simulation model of grid-connected/off-grid switching of microgrid energy storage system was built under MATLAB/Simulink simulation platform,and compared with the traditional PID control method.The results show that the control method proposed in this paper can effectively control the mode switching of the microgrid.The comparison shows that the LADRC control method is superior to the traditional PID in terms of overshoot size,response speed,and steady-state error.